38 files changed, 1612 insertions, 0 deletions
diff --git a/common/src/Common/Message/Key.hs b/common/src/Common/Message/Key.hs
new file mode 100644
index 0000000..f3b0837
--- /dev/null
+++ b/common/src/Common/Message/Key.hs
@@ -0,0 +1,150 @@
+module Common.Message.Key
+  ( Key(..)
+  ) where
+
+import           Data.Text
+
+data Key =
+
+  App_Title
+
+  | Category_Add
+  | Category_Clone
+  | Category_Color
+  | Category_DeleteConfirm
+  | Category_Edit
+  | Category_Empty
+  | Category_Name
+  | Category_NotDeleted
+  | Category_Title
+  | Category_Used
+
+  | Date_Long Int Text Int
+  | Date_Short Int Int Int
+  | Date_ShortMonthAndYear Int Int
+
+  | Dialog_Confirm
+  | Dialog_Undo
+
+  | Error_CategoryCreate
+  | Error_CategoryDelete
+  | Error_CategoryEdit
+  | Error_IncomeCreate
+  | Error_IncomeDelete
+  | Error_IncomeEdit
+  | Error_PaymentCreate
+  | Error_PaymentDelete
+  | Error_PaymentEdit
+  | Error_SignOut
+
+  | Form_AlreadyExists
+  | Form_NonEmpty
+  | Form_MinChars Int
+  | Form_NonNullNumber
+  | Form_GreaterIntThan Int
+  | Form_InvalidCategory
+  | Form_InvalidColor
+  | Form_InvalidDate
+  | Form_InvalidInt
+  | Form_InvalidString
+  | Form_SmallerIntThan Int
+
+  | HttpError_BadPayload
+  | HttpError_BadUrl
+  | HttpError_NetworkError
+  | HttpError_Timeout
+
+  | Income_AddLong
+  | Income_AddShort
+  | Income_Name
+  | Income_Amount
+  | Income_Clone
+  | Income_CumulativeSince Text
+  | Income_Date
+  | Income_DeleteConfirm
+  | Income_Edit
+  | Income_Empty
+  | Income_MonthlyNet
+  | Income_Title
+
+  | Month_January
+  | Month_February
+  | Month_March
+  | Month_April
+  | Month_May
+  | Month_June
+  | Month_July
+  | Month_August
+  | Month_September
+  | Month_October
+  | Month_November
+  | Month_December
+
+  | PageNotFound_Title
+
+  | Payment_Add
+  | Payment_Balanced
+  | Payment_By Text Text
+  | Payment_Category
+  | Payment_CloneLong
+  | Payment_CloneShort
+  | Payment_Cost
+  | Payment_Date
+  | Payment_Delete
+  | Payment_DeleteConfirm
+  | Payment_EditLong
+  | Payment_EditShort
+  | Payment_Empty
+  | Payment_Frequency
+  | Payment_InvalidFrequency
+  | Payment_Many
+  | Payment_MonthlyFemale
+  | Payment_MonthlyMale
+  | Payment_Name
+  | Payment_NotDeleted
+  | Payment_One
+  | Payment_PunctualFemale
+  | Payment_PunctualMale
+  | Payment_Title
+  | Payment_User
+  | Payment_Worth Text Text
+
+  | Search_Monthly
+  | Search_Name
+  | Search_Punctual
+
+  | Secure_Forbidden
+  | Secure_Unauthorized
+
+  | SignIn_Button
+  | SignIn_DisconnectSuccess
+  | SignIn_InvalidCredentials
+  | SignIn_EmailLabel
+  | SignIn_PasswordLabel
+
+  | Statistics_Title
+  | Statistics_ByMonthsAndMean Text Text
+  | Statistics_TotalPayments
+  | Statistics_TotalIncomes
+
+  | WeeklyReport_Empty
+  | WeeklyReport_IncomesCreated Int
+  | WeeklyReport_IncomesDeleted Int
+  | WeeklyReport_IncomesEdited Int
+  | WeeklyReport_IncomeCreated Int
+  | WeeklyReport_IncomeDeleted Int
+  | WeeklyReport_IncomeEdited Int
+  | WeeklyReport_PayedFor Text Text Text Text
+  | WeeklyReport_PayedForNot Text Text Text Text
+  | WeeklyReport_PayedFrom Text Text Text
+  | WeeklyReport_PayedFromNot Text Text Text
+  | WeeklyReport_PaymentsCreated Int
+  | WeeklyReport_PaymentsDeleted Int
+  | WeeklyReport_PaymentsEdited Int
+  | WeeklyReport_PaymentCreated Int
+  | WeeklyReport_PaymentDeleted Int
+  | WeeklyReport_PaymentEdited Int
+  | WeeklyReport_Title
+
+  | NotFound_Message
+  | NotFound_LinkMessage
diff --git a/common/src/Common/Message/Lang.hs b/common/src/Common/Message/Lang.hs
new file mode 100644
index 0000000..0a32ede
--- /dev/null
+++ b/common/src/Common/Message/Lang.hs
@@ -0,0 +1,7 @@
+module Common.Message.Lang
+  ( Lang(..)
+  ) where
+
+data Lang =
+  English
+  | French
diff --git a/common/src/Common/Message/Translation.hs b/common/src/Common/Message/Translation.hs
new file mode 100644
index 0000000..222e669
--- /dev/null
+++ b/common/src/Common/Message/Translation.hs
@@ -0,0 +1,655 @@
+module Common.Message.Translation
+  ( get
+  ) where
+
+import           Data.Text           (Text)
+import qualified Data.Text           as T
+
+import           Common.Message.Key
+import           Common.Message.Lang (Lang (..))
+
+get :: Lang -> Key -> Text
+get = m
+
+m :: Lang -> Key -> Text
+
+m l App_Title =
+  case l of
+    English -> "Shared Cost"
+    French  -> "Partage des frais"
+
+m l Category_Add =
+  case l of
+    English -> "Add an category"
+    French  -> "Ajouter une catégorie"
+
+m l Category_Clone =
+  case l of
+    English -> "Clone an category"
+    French  -> "Cloner une catégorie"
+
+m l Category_Color =
+  case l of
+    English -> "Color"
+    French  -> "Couleur"
+
+m l Category_DeleteConfirm =
+  case l of
+    English -> "Are you sure to delete this category ?"
+    French  -> "Voulez-vous vraiment supprimer cette catégorie ?"
+
+m l Category_Edit =
+  case l of
+    English -> "Edit an category"
+    French  -> "Modifier une catégorie"
+
+m l Category_Empty =
+  case l of
+    English -> "No category."
+    French  -> "Aucune catégorie."
+
+m l Category_Name =
+  case l of
+    English -> "Name"
+    French  -> "Nom"
+
+m l Category_NotDeleted =
+  case l of
+    English -> "The category could not have been deleted."
+    French  -> "La catégorie n’a pas pu être supprimé."
+
+m l Category_Title =
+  case l of
+    English -> "Categories"
+    French  -> "Catégories"
+
+m l Category_Used =
+  case l of
+    English -> "This category is currently being used"
+    French  -> "Cette catégorie est actuellement utilisée"
+
+m l (Date_Short day month year) =
+  case l of
+    English ->
+      T.intercalate "-" [ padded year 4, padded month 2, padded day 2 ]
+    French ->
+      T.intercalate "/" [ padded day 2, padded month 2, padded year 4 ]
+  where padded num pad =
+          let str = show num
+          in  T.pack $ replicate (pad - length str) '0' ++ str
+
+m l (Date_ShortMonthAndYear month year) =
+  case l of
+    English ->
+      T.intercalate "-" . map (T.pack . show) $ [ year, month ]
+    French ->
+      T.intercalate "/" . map (T.pack . show) $ [ month, year ]
+
+m l (Date_Long day month year) =
+  case l of
+    English ->
+      T.concat [ month, " " , T.pack . show $ day, ", ", T.pack . show $ year ]
+    French ->
+      T.intercalate " " [ T.pack . show $ day, month, T.pack . show $ year ]
+
+m l Dialog_Confirm =
+  case l of
+    English -> "Confirm"
+    French  -> "Confirmer"
+
+m l Dialog_Undo =
+  case l of
+    English -> "Undo"
+    French  -> "Annuler"
+
+m l Error_CategoryCreate =
+  case l of
+    English -> "Error at category creation"
+    French  -> "Erreur lors de la création de la catégorie"
+
+m l Error_CategoryDelete =
+  case l of
+    English -> "Error at category deletion"
+    French  -> "Erreur lors de la suppression de la catégorie"
+
+m l Error_CategoryEdit =
+  case l of
+    English -> "Error at category edition"
+    French  -> "Erreur lors de la modification de la catégorie"
+
+m l Error_IncomeCreate =
+  case l of
+    English -> "Error at income creation"
+    French  -> "Erreur lors de la création du revenu"
+
+m l Error_IncomeDelete =
+  case l of
+    English -> "Error at income deletion"
+    French  -> "Erreur lors de la suppression du revenu"
+
+m l Error_IncomeEdit =
+  case l of
+    English -> "Error at income edition"
+    French  -> "Erreur lors de la modification du revenu"
+
+m l Error_PaymentCreate =
+  case l of
+    English -> "Error at payment creation"
+    French  -> "Erreur lors de la création du paiement"
+
+m l Error_PaymentDelete =
+  case l of
+    English -> "Error at payment deletion"
+    French  -> "Erreur lors de la suppression du paiement"
+
+m l Error_PaymentEdit =
+  case l of
+    English -> "Error at payment edition"
+    French  -> "Erreur lors de la modification du paiement"
+
+m l Error_SignOut =
+  case l of
+    English -> "Error at sign out"
+    French  -> "Erreur lors de la déconnexion"
+
+m l Form_AlreadyExists =
+  case l of
+    English -> "Dupplicate field"
+    French  -> "Doublon"
+
+m l Form_NonEmpty =
+  case l of
+    English -> "Required field"
+    French  -> "Champ requis"
+
+m l (Form_MinChars number) =
+  case l of
+    English -> T.concat [ "This field must contains at least ", T.pack . show $ number, " characters" ]
+    French  -> T.concat [ "Ce champ doit contenir au moins ", T.pack . show $ number, " caractères" ]
+
+m l Form_NonNullNumber =
+  case l of
+    English -> "Number must not be null"
+    French  -> "Le nombre ne doit pas être nul"
+
+m l (Form_GreaterIntThan number) =
+  case l of
+    English -> T.concat [ "Integer smaller than ", T.pack . show $ number, " or equal required" ]
+    French  -> T.concat [ "Entier inférieur ou égal à ", T.pack . show $ number, " requis" ]
+
+m l Form_InvalidCategory =
+  case l of
+    English -> "Invalid category"
+    French  -> "Catégorie invalide"
+
+m l Form_InvalidColor =
+  case l of
+    English -> "Invalid color"
+    French  -> "Couleur invalide"
+
+m l Form_InvalidDate =
+  case l of
+    English -> "Date required"
+    French  -> "Date requise"
+
+m l Form_InvalidInt =
+  case l of
+    English -> "Integer required"
+    French  -> "Entier requis"
+
+m l Form_InvalidString =
+  case l of
+    English -> "String required"
+    French  -> "Chaîne de caractères requise"
+
+m l (Form_SmallerIntThan number) =
+  case l of
+    English -> T.concat [ "Integer bigger than ", T.pack . show $ number, " or equal required" ]
+    French  -> T.concat [ "Entier supérieur ou égal à ", T.pack . show $ number, " requis" ]
+
+m l HttpError_BadPayload =
+  case l of
+    English -> "Bad payload server error"
+    French  -> "Contenu inattendu en provenance du serveur"
+
+m l HttpError_BadUrl =
+  case l of
+    English -> "URL not valid"
+    French  -> "l’URL n’est pas valide"
+
+m l HttpError_NetworkError =
+  case l of
+    English -> "Network can not be reached"
+    French  -> "Le serveur n’est pas accessible"
+
+m l HttpError_Timeout =
+  case l of
+    English -> "Timeout server error"
+    French  -> "Le serveur met trop de temps à répondre"
+
+m l Income_AddLong =
+  case l of
+    English -> "Add an income"
+    French  -> "Ajouter un revenu"
+
+m l Income_AddShort =
+  case l of
+    English -> "Add"
+    French  -> "Ajouter"
+
+m l Income_Name =
+  case l of
+    English -> "Name"
+    French  -> "Nom"
+
+m l Income_Amount =
+  case l of
+    English -> "Income"
+    French  -> "Revenu"
+
+m l Income_Clone =
+  case l of
+    English -> "Clone an income"
+    French  -> "Cloner un revenu"
+
+m l (Income_CumulativeSince since) =
+  case l of
+    English -> T.concat [ "Cumulative incomes since ", since ]
+    French  -> T.concat [ "Revenus nets cumulés depuis le ", since ]
+
+m l Income_Date =
+  case l of
+    English -> "Date"
+    French  -> "Date"
+
+m l Income_DeleteConfirm =
+  case l of
+    English -> "Are you sure to delete this income ?"
+    French  -> "Voulez-vous vraiment supprimer ce revenu ?"
+
+m l Income_Edit =
+  case l of
+    English -> "Edit an income"
+    French  -> "Modifier un revenu"
+
+m l Income_Empty =
+  case l of
+    English -> "No income."
+    French  -> "Aucun revenu."
+
+m l Income_MonthlyNet =
+  case l of
+    English -> "Net monthly incomes"
+    French  -> "Revenus mensuels nets"
+
+m l Income_Title =
+  case l of
+    English -> "Income"
+    French  -> "Revenu"
+
+m l Month_January =
+  case l of
+    English -> "january"
+    French  -> "janvier"
+
+m l Month_February =
+  case l of
+    English -> "february"
+    French  -> "février"
+
+m l Month_March =
+  case l of
+    English -> "march"
+    French  -> "mars"
+
+m l Month_April =
+  case l of
+    English -> "april"
+    French  -> "avril"
+
+m l Month_May =
+  case l of
+    English -> "may"
+    French  -> "mai"
+
+m l Month_June =
+  case l of
+    English -> "june"
+    French  -> "juin"
+
+m l Month_July =
+  case l of
+    English -> "july"
+    French  -> "juillet"
+
+m l Month_August =
+  case l of
+    English -> "august"
+    French  -> "août"
+
+m l Month_September =
+  case l of
+    English -> "september"
+    French  -> "septembre"
+
+m l Month_October =
+  case l of
+    English -> "october"
+    French  -> "octobre"
+
+m l Month_November =
+  case l of
+    English -> "november"
+    French  -> "novembre"
+
+m l Month_December =
+  case l of
+    English -> "december"
+    French  -> "décembre"
+
+m l PageNotFound_Title =
+  case l of
+    English -> "Page not found"
+    French  -> "Page introuvable"
+
+m l Payment_Add =
+  case l of
+    English -> "Add a payment"
+    French  -> "Ajouter un paiement"
+
+m l Payment_Balanced =
+  case l of
+    English -> "Payments are balanced."
+    French  -> "Les paiements sont équilibrés."
+
+m l (Payment_By key value) =
+  case l of
+    English -> T.concat [ key, ": ", value ]
+    French  -> T.concat [ key, " : ", value ]
+
+m l Payment_Category =
+  case l of
+    English -> "Category"
+    French  -> "Catégorie"
+
+m l Payment_CloneLong =
+  case l of
+    English -> "Clone a payment"
+    French  -> "Cloner un paiement"
+
+m l Payment_CloneShort =
+  case l of
+    English -> "Clone"
+    French  -> "Cloner"
+
+m l Payment_Cost =
+  case l of
+    English -> "Cost"
+    French  -> "Coût"
+
+m l Payment_Date =
+  case l of
+    English -> "Date"
+    French  -> "Date"
+
+m l Payment_Delete =
+  case l of
+    English -> "Delete"
+    French  -> "Supprimer"
+
+m l Payment_DeleteConfirm =
+  case l of
+    English -> "Are you sure to delete this payment ?"
+    French  -> "Voulez-vous vraiment supprimer ce paiement ?"
+
+m l Payment_EditLong =
+  case l of
+    English -> "Edit a payment"
+    French  -> "Modifier un paiement"
+
+m l Payment_EditShort =
+  case l of
+    English -> "Edit"
+    French  -> "Modifier"
+
+m l Payment_Empty =
+  case l of
+    English -> "No payment found from your search criteria."
+    French  -> "Aucun paiement ne correspond à vos critères de recherches."
+
+m l Payment_Frequency =
+  case l of
+    English -> "Frequency"
+    French  -> "Fréquence"
+
+m l Payment_InvalidFrequency =
+  case l of
+    English -> "Invalid frequency"
+    French  -> "Fréquence invalide"
+
+m l Payment_Many =
+  case l of
+    English -> "payments"
+    French  -> "paiements"
+
+m l Payment_MonthlyFemale =
+  case l of
+    English -> "Monthly"
+    French  -> "Mensuelle"
+
+m l Payment_MonthlyMale =
+  case l of
+    English -> "Monthly"
+    French  -> "Mensuel"
+
+m l Payment_Name =
+  case l of
+    English -> "Name"
+    French  -> "Nom"
+
+m l Payment_NotDeleted =
+  case l of
+    English -> "The payment could not have been deleted."
+    French  -> "Le paiement n’a pas pu être supprimé."
+
+m l Payment_One =
+  case l of
+    English -> "payment"
+    French  -> "paiement"
+
+m l Payment_PunctualFemale =
+  case l of
+    English -> "Punctual"
+    French  -> "Ponctuelle"
+
+m l Payment_PunctualMale =
+  case l of
+    English -> "Punctual"
+    French  -> "Ponctuel"
+
+m l Payment_Title =
+  case l of
+    English -> "Payments"
+    French  -> "Paiements"
+
+m l Payment_User =
+  case l of
+    English -> "Payer"
+    French  -> "Payeur"
+
+m l (Payment_Worth subject amount) =
+  case l of
+    English -> T.concat [ subject, " worth ", amount ]
+    French  -> T.concat [ subject, " comptabilisant ", amount ]
+
+m l Search_Monthly =
+  case l of
+    English -> "Monthly"
+    French  -> "Mensuel"
+
+m l Search_Name =
+  case l of
+    English -> "Search"
+    French  -> "Recherche"
+
+m l Search_Punctual =
+  case l of
+    English -> "Punctual"
+    French  -> "Ponctuel"
+
+m l Secure_Unauthorized =
+  case l of
+    English -> "You are not authorized to sign in."
+    French  -> "Tu n’es pas autorisé à te connecter."
+
+m l Secure_Forbidden =
+  case l of
+    English -> "You need to be logged in to perform this action"
+    French  -> "Tu dois te connecter pour effectuer cette action"
+
+m l SignIn_Button =
+  case l of
+    English -> "Sign in"
+    French  -> "Connexion"
+
+m l SignIn_DisconnectSuccess =
+  case l of
+    English -> "You have successfully disconnected"
+    French  -> "Vous êtes à présent déconnecté."
+
+m l SignIn_InvalidCredentials =
+  case l of
+    English -> "Your credentials are not valid."
+    French  -> "Vos identifiants de connexion ne sont pas valides."
+
+m l SignIn_EmailLabel =
+  case l of
+    English -> "Email"
+    French  -> "Courriel"
+
+m l SignIn_PasswordLabel =
+  case l of
+    English -> "Password"
+    French  -> "Mot de passe"
+
+m l (Statistics_ByMonthsAndMean paymentMean incomeMean ) =
+  case l of
+    English ->
+      T.concat [ "Payments by category (mean ", paymentMean, ") and income (mean ", incomeMean, ") by month" ]
+    French  ->
+      T.concat [ "Paiements par catégorie (moy. ", paymentMean, ") et revenu (moy. ", incomeMean, ") par mois" ]
+
+m l Statistics_Title =
+  case l of
+    English -> "Statistics"
+    French  -> "Statistiques"
+
+m l Statistics_TotalPayments =
+  case l of
+    English -> "Payment total"
+    French  -> "Total des paiements"
+
+m l Statistics_TotalIncomes =
+  case l of
+    English -> "Income total"
+    French  -> "Total des revenus"
+
+m l WeeklyReport_Empty =
+  case l of
+    English -> "No activity the previous week."
+    French  -> "Pas d’activité la semaine passée."
+
+m l (WeeklyReport_IncomesCreated count) =
+  case l of
+    English -> T.concat [ T.pack . show $ count, " incomes created:" ]
+    French  -> T.concat [ T.pack . show $ count, " revenus créés :" ]
+
+m l (WeeklyReport_IncomesDeleted count) =
+  case l of
+    English -> T.concat [ T.pack . show $ count, " incomes deleted:" ]
+    French  -> T.concat [ T.pack . show $ count, " revenus supprimés :" ]
+
+m l (WeeklyReport_IncomesEdited count) =
+  case l of
+    English -> T.concat [ T.pack . show $ count, " incomes edited:" ]
+    French  -> T.concat [ T.pack . show $ count, " revenus modifiés :" ]
+
+m l (WeeklyReport_IncomeCreated count) =
+  case l of
+    English -> T.concat [ T.pack . show $ count, " income created:" ]
+    French  -> T.concat [ T.pack . show $ count, " revenu créé :" ]
+
+m l (WeeklyReport_IncomeDeleted count) =
+  case l of
+    English -> T.concat [ T.pack . show $ count, " income deleted:" ]
+    French  -> T.concat [ T.pack . show $ count, " revenu supprimé :" ]
+
+m l (WeeklyReport_IncomeEdited count) =
+  case l of
+    English -> T.concat [ T.pack . show $ count, " income edited:" ]
+    French  -> T.concat [ T.pack . show $ count, " revenu modifié :" ]
+
+m l (WeeklyReport_PayedFor name amount for at) =
+  case l of
+    English -> T.concat [ name, " payed ", amount, " for “", for, "” at ", at ]
+    French  -> T.concat [ name, " a payé ", amount, " concernant « ", for, " » le ", at ]
+
+m l (WeeklyReport_PayedForNot name amount for at) =
+  case l of
+    English -> T.concat [ name, " didn’t pay ", amount, " for “", for, "” at ", at ]
+    French  -> T.concat [ name, " n’a pas payé ", amount, " concernant « ", for, " » le ", at ]
+
+m l (WeeklyReport_PayedFrom name amount for) =
+  case l of
+    English -> T.concat [ name, " is payed ", amount, " of net monthly income from ", for ]
+    French  -> T.concat [ name, " est payé ", amount, " net par mois à partir du ", for ]
+
+m l (WeeklyReport_PayedFromNot name amount for) =
+  case l of
+    English -> T.concat [ name, " isn’t payed ", amount, " of net monthly income from ", for ]
+    French  -> T.concat [ name, " n’est pas payé ", amount, " net par mois à partir du ", for ]
+
+m l (WeeklyReport_PaymentsCreated count) =
+  case l of
+    English -> T.concat [ T.pack . show $ count, " payments created:" ]
+    French  -> T.concat [ T.pack . show $ count, " paiements créés :" ]
+
+m l (WeeklyReport_PaymentsDeleted count) =
+  case l of
+    English -> T.concat [ T.pack . show $ count, " payments deleted:" ]
+    French  -> T.concat [ T.pack . show $ count, " paiements supprimés :" ]
+
+m l (WeeklyReport_PaymentsEdited count) =
+  case l of
+    English -> T.concat [ T.pack . show $ count, " payments edited:" ]
+    French  -> T.concat [ T.pack . show $ count, " paiements modifiés :" ]
+
+m l (WeeklyReport_PaymentCreated count) =
+  case l of
+    English -> T.concat [ T.pack . show $ count, " payment created:" ]
+    French  -> T.concat [ T.pack . show $ count, " paiement créé :" ]
+
+m l (WeeklyReport_PaymentDeleted count) =
+  case l of
+    English -> T.concat [ T.pack . show $ count, " payment deleted:" ]
+    French  -> T.concat [ T.pack . show $ count, " paiement supprimé :" ]
+
+m l (WeeklyReport_PaymentEdited count) =
+  case l of
+    English -> T.concat [ T.pack . show $ count, " payment edited:" ]
+    French  -> T.concat [ T.pack . show $ count, " paiement modifié :" ]
+
+m l WeeklyReport_Title =
+  case l of
+    English -> "Weekly report"
+    French  -> "Rapport hebdomadaire"
+
+m l NotFound_Message =
+  case l of
+    English -> "There is nothing here!"
+    French  -> "Il n’y a rien à voir ici."
+
+m l NotFound_LinkMessage =
+  case l of
+    English -> "Go back to the home page."
+    French  -> "Retour à l’accueil."
diff --git a/common/src/Common/Model.hs b/common/src/Common/Model.hs
new file mode 100644
index 0000000..979d876
--- /dev/null
+++ b/common/src/Common/Model.hs
@@ -0,0 +1,26 @@
+module Common.Model (module X) where
+
+import           Common.Model.Category           as X
+import           Common.Model.CategoryPage       as X
+import           Common.Model.CreateCategoryForm as X
+import           Common.Model.CreateIncomeForm   as X
+import           Common.Model.CreatePaymentForm  as X
+import           Common.Model.Currency           as X
+import           Common.Model.EditCategoryForm   as X
+import           Common.Model.EditIncome         as X
+import           Common.Model.EditIncomeForm     as X
+import           Common.Model.EditPaymentForm    as X
+import           Common.Model.Email              as X
+import           Common.Model.ExceedingPayer     as X
+import           Common.Model.Frequency          as X
+import           Common.Model.Income             as X
+import           Common.Model.IncomeHeader       as X
+import           Common.Model.IncomePage         as X
+import           Common.Model.Init               as X
+import           Common.Model.Password           as X
+import           Common.Model.Payment            as X
+import           Common.Model.PaymentHeader      as X
+import           Common.Model.PaymentPage        as X
+import           Common.Model.SignInForm         as X
+import           Common.Model.Stats              as X
+import           Common.Model.User               as X
diff --git a/common/src/Common/Model/Category.hs b/common/src/Common/Model/Category.hs
new file mode 100644
index 0000000..cc3f795
--- /dev/null
+++ b/common/src/Common/Model/Category.hs
@@ -0,0 +1,24 @@
+module Common.Model.Category
+  ( CategoryId
+  , Category(..)
+  ) where
+
+import           Data.Aeson   (FromJSON, ToJSON)
+import           Data.Int     (Int64)
+import           Data.Text    (Text)
+import           Data.Time    (UTCTime)
+import           GHC.Generics (Generic)
+
+type CategoryId = Int64
+
+data Category = Category
+  { _category_id        :: CategoryId
+  , _category_name      :: Text
+  , _category_color     :: Text
+  , _category_createdAt :: UTCTime
+  , _category_editedAt  :: Maybe UTCTime
+  , _category_deletedAt :: Maybe UTCTime
+  } deriving (Eq, Show, Generic)
+
+instance FromJSON Category
+instance ToJSON Category
diff --git a/common/src/Common/Model/CategoryPage.hs b/common/src/Common/Model/CategoryPage.hs
new file mode 100644
index 0000000..e20f49f
--- /dev/null
+++ b/common/src/Common/Model/CategoryPage.hs
@@ -0,0 +1,18 @@
+module Common.Model.CategoryPage
+  ( CategoryPage(..)
+  ) where
+
+import           Data.Aeson            (FromJSON, ToJSON)
+import           GHC.Generics          (Generic)
+
+import           Common.Model.Category (Category, CategoryId)
+
+data CategoryPage = CategoryPage
+  { _categoryPage_page           :: Int
+  , _categoryPage_categories     :: [Category]
+  , _categoryPage_usedCategories :: [CategoryId]
+  , _categoryPage_totalCount     :: Int
+  } deriving (Eq, Show, Generic)
+
+instance FromJSON CategoryPage
+instance ToJSON CategoryPage
diff --git a/common/src/Common/Model/CreateCategoryForm.hs b/common/src/Common/Model/CreateCategoryForm.hs
new file mode 100644
index 0000000..4668ef4
--- /dev/null
+++ b/common/src/Common/Model/CreateCategoryForm.hs
@@ -0,0 +1,15 @@
+module Common.Model.CreateCategoryForm
+  ( CreateCategoryForm(..)
+  ) where
+
+import           Data.Aeson   (FromJSON, ToJSON)
+import           Data.Text    (Text)
+import           GHC.Generics (Generic)
+
+data CreateCategoryForm = CreateCategoryForm
+  { _createCategoryForm_name  :: Text
+  , _createCategoryForm_color :: Text
+  } deriving (Show, Generic)
+
+instance FromJSON CreateCategoryForm
+instance ToJSON CreateCategoryForm
diff --git a/common/src/Common/Model/CreateIncomeForm.hs b/common/src/Common/Model/CreateIncomeForm.hs
new file mode 100644
index 0000000..e83bf0a
--- /dev/null
+++ b/common/src/Common/Model/CreateIncomeForm.hs
@@ -0,0 +1,15 @@
+module Common.Model.CreateIncomeForm
+  ( CreateIncomeForm(..)
+  ) where
+
+import           Data.Aeson   (FromJSON, ToJSON)
+import           Data.Text    (Text)
+import           GHC.Generics (Generic)
+
+data CreateIncomeForm = CreateIncomeForm
+  { _createIncomeForm_amount :: Text
+  , _createIncomeForm_date   :: Text
+  } deriving (Show, Generic)
+
+instance FromJSON CreateIncomeForm
+instance ToJSON CreateIncomeForm
diff --git a/common/src/Common/Model/CreatePaymentForm.hs b/common/src/Common/Model/CreatePaymentForm.hs
new file mode 100644
index 0000000..60c5423
--- /dev/null
+++ b/common/src/Common/Model/CreatePaymentForm.hs
@@ -0,0 +1,21 @@
+module Common.Model.CreatePaymentForm
+  ( CreatePaymentForm(..)
+  ) where
+
+import           Data.Aeson             (FromJSON, ToJSON)
+import           Data.Text              (Text)
+import           GHC.Generics           (Generic)
+
+import           Common.Model.Category  (CategoryId)
+import           Common.Model.Frequency (Frequency)
+
+data CreatePaymentForm = CreatePaymentForm
+  { _createPaymentForm_name      :: Text
+  , _createPaymentForm_cost      :: Text
+  , _createPaymentForm_date      :: Text
+  , _createPaymentForm_category  :: CategoryId
+  , _createPaymentForm_frequency :: Frequency
+  } deriving (Show, Generic)
+
+instance FromJSON CreatePaymentForm
+instance ToJSON CreatePaymentForm
diff --git a/common/src/Common/Model/Currency.hs b/common/src/Common/Model/Currency.hs
new file mode 100644
index 0000000..175aeba
--- /dev/null
+++ b/common/src/Common/Model/Currency.hs
@@ -0,0 +1,12 @@
+module Common.Model.Currency
+  ( Currency(..)
+  ) where
+
+import           Data.Aeson   (FromJSON, ToJSON)
+import           Data.Text    (Text)
+import           GHC.Generics (Generic)
+
+newtype Currency = Currency Text deriving (Show, Generic)
+
+instance FromJSON Currency
+instance ToJSON Currency
diff --git a/common/src/Common/Model/EditCategoryForm.hs b/common/src/Common/Model/EditCategoryForm.hs
new file mode 100644
index 0000000..a2ceca0
--- /dev/null
+++ b/common/src/Common/Model/EditCategoryForm.hs
@@ -0,0 +1,18 @@
+module Common.Model.EditCategoryForm
+  ( EditCategoryForm(..)
+  ) where
+
+import           Data.Aeson            (FromJSON, ToJSON)
+import           Data.Text             (Text)
+import           GHC.Generics          (Generic)
+
+import           Common.Model.Category (CategoryId)
+
+data EditCategoryForm = EditCategoryForm
+  { _editCategoryForm_id    :: CategoryId
+  , _editCategoryForm_name  :: Text
+  , _editCategoryForm_color :: Text
+  } deriving (Show, Generic)
+
+instance FromJSON EditCategoryForm
+instance ToJSON EditCategoryForm
diff --git a/common/src/Common/Model/EditIncome.hs b/common/src/Common/Model/EditIncome.hs
new file mode 100644
index 0000000..0e65f12
--- /dev/null
+++ b/common/src/Common/Model/EditIncome.hs
@@ -0,0 +1,17 @@
+module Common.Model.EditIncome
+  ( EditIncome(..)
+  ) where
+
+import           Data.Aeson          (FromJSON)
+import           Data.Time.Calendar  (Day)
+import           GHC.Generics        (Generic)
+
+import           Common.Model.Income (IncomeId)
+
+data EditIncome = EditIncome
+  { _editIncome_id     :: IncomeId
+  , _editIncome_date   :: Day
+  , _editIncome_amount :: Int
+  } deriving (Show, Generic)
+
+instance FromJSON EditIncome
diff --git a/common/src/Common/Model/EditIncomeForm.hs b/common/src/Common/Model/EditIncomeForm.hs
new file mode 100644
index 0000000..ff975fc
--- /dev/null
+++ b/common/src/Common/Model/EditIncomeForm.hs
@@ -0,0 +1,18 @@
+module Common.Model.EditIncomeForm
+  ( EditIncomeForm(..)
+  ) where
+
+import           Data.Aeson          (FromJSON, ToJSON)
+import           Data.Text           (Text)
+import           GHC.Generics        (Generic)
+
+import           Common.Model.Income (IncomeId)
+
+data EditIncomeForm = EditIncomeForm
+  { _editIncomeForm_id     :: IncomeId
+  , _editIncomeForm_amount :: Text
+  , _editIncomeForm_date   :: Text
+  } deriving (Show, Generic)
+
+instance FromJSON EditIncomeForm
+instance ToJSON EditIncomeForm
diff --git a/common/src/Common/Model/EditPaymentForm.hs b/common/src/Common/Model/EditPaymentForm.hs
new file mode 100644
index 0000000..168c9ff
--- /dev/null
+++ b/common/src/Common/Model/EditPaymentForm.hs
@@ -0,0 +1,23 @@
+module Common.Model.EditPaymentForm
+  ( EditPaymentForm(..)
+  ) where
+
+import           Data.Aeson             (FromJSON, ToJSON)
+import           Data.Text              (Text)
+import           GHC.Generics           (Generic)
+
+import           Common.Model.Category  (CategoryId)
+import           Common.Model.Frequency (Frequency)
+import           Common.Model.Payment   (PaymentId)
+
+data EditPaymentForm = EditPaymentForm
+  { _editPaymentForm_id        :: PaymentId
+  , _editPaymentForm_name      :: Text
+  , _editPaymentForm_cost      :: Text
+  , _editPaymentForm_date      :: Text
+  , _editPaymentForm_category  :: CategoryId
+  , _editPaymentForm_frequency :: Frequency
+  } deriving (Show, Generic)
+
+instance FromJSON EditPaymentForm
+instance ToJSON EditPaymentForm
diff --git a/common/src/Common/Model/Email.hs b/common/src/Common/Model/Email.hs
new file mode 100644
index 0000000..e938f83
--- /dev/null
+++ b/common/src/Common/Model/Email.hs
@@ -0,0 +1,12 @@
+module Common.Model.Email
+  ( Email(..)
+  ) where
+
+import           Data.Aeson   (FromJSON, ToJSON)
+import           Data.Text    (Text)
+import           GHC.Generics (Generic)
+
+newtype Email = Email Text deriving (Show, Generic)
+
+instance FromJSON Email
+instance ToJSON Email
diff --git a/common/src/Common/Model/ExceedingPayer.hs b/common/src/Common/Model/ExceedingPayer.hs
new file mode 100644
index 0000000..b7d3efb
--- /dev/null
+++ b/common/src/Common/Model/ExceedingPayer.hs
@@ -0,0 +1,16 @@
+module Common.Model.ExceedingPayer
+  ( ExceedingPayer(..)
+  ) where
+
+import           Data.Aeson        (FromJSON, ToJSON)
+import           GHC.Generics      (Generic)
+
+import           Common.Model.User (UserId)
+
+data ExceedingPayer = ExceedingPayer
+  { _exceedingPayer_userId :: UserId
+  , _exceedingPayer_amount :: Int
+  } deriving (Eq, Show, Generic)
+
+instance FromJSON ExceedingPayer
+instance ToJSON ExceedingPayer
diff --git a/common/src/Common/Model/Frequency.hs b/common/src/Common/Model/Frequency.hs
new file mode 100644
index 0000000..48e75ea
--- /dev/null
+++ b/common/src/Common/Model/Frequency.hs
@@ -0,0 +1,14 @@
+module Common.Model.Frequency
+  ( Frequency(..)
+  ) where
+
+import           Data.Aeson   (FromJSON, ToJSON)
+import           GHC.Generics (Generic)
+
+data Frequency =
+  Punctual
+  | Monthly
+  deriving (Eq, Read, Show, Generic, Ord)
+
+instance FromJSON Frequency
+instance ToJSON Frequency
diff --git a/common/src/Common/Model/Income.hs b/common/src/Common/Model/Income.hs
new file mode 100644
index 0000000..57d07f1
--- /dev/null
+++ b/common/src/Common/Model/Income.hs
@@ -0,0 +1,27 @@
+module Common.Model.Income
+  ( IncomeId
+  , Income(..)
+  ) where
+
+import           Data.Aeson         (FromJSON, ToJSON)
+import           Data.Int           (Int64)
+import           Data.Time          (UTCTime)
+import           Data.Time.Calendar (Day)
+import           GHC.Generics       (Generic)
+
+import           Common.Model.User  (UserId)
+
+type IncomeId = Int64
+
+data Income = Income
+  { _income_id        :: IncomeId
+  , _income_userId    :: UserId
+  , _income_date      :: Day
+  , _income_amount    :: Int
+  , _income_createdAt :: UTCTime
+  , _income_editedAt  :: Maybe UTCTime
+  , _income_deletedAt :: Maybe UTCTime
+  } deriving (Eq, Show, Generic)
+
+instance FromJSON Income
+instance ToJSON Income
diff --git a/common/src/Common/Model/IncomeHeader.hs b/common/src/Common/Model/IncomeHeader.hs
new file mode 100644
index 0000000..7e712e8
--- /dev/null
+++ b/common/src/Common/Model/IncomeHeader.hs
@@ -0,0 +1,18 @@
+module Common.Model.IncomeHeader
+  ( IncomeHeader(..)
+  ) where
+
+import           Data.Aeson         (FromJSON, ToJSON)
+import           Data.Map           (Map)
+import           Data.Time.Calendar (Day)
+import           GHC.Generics       (Generic)
+
+import           Common.Model.User  (UserId)
+
+data IncomeHeader = IncomeHeader
+  { _incomeHeader_since  :: Maybe Day
+  , _incomeHeader_byUser :: Map UserId Int
+  } deriving (Eq, Show, Generic)
+
+instance FromJSON IncomeHeader
+instance ToJSON IncomeHeader
diff --git a/common/src/Common/Model/IncomePage.hs b/common/src/Common/Model/IncomePage.hs
new file mode 100644
index 0000000..977b0ea
--- /dev/null
+++ b/common/src/Common/Model/IncomePage.hs
@@ -0,0 +1,19 @@
+module Common.Model.IncomePage
+  ( IncomePage(..)
+  ) where
+
+import           Data.Aeson                (FromJSON, ToJSON)
+import           GHC.Generics              (Generic)
+
+import           Common.Model.Income       (Income)
+import           Common.Model.IncomeHeader (IncomeHeader)
+
+data IncomePage = IncomePage
+  { _incomePage_page       :: Int
+  , _incomePage_header     :: IncomeHeader
+  , _incomePage_incomes    :: [Income]
+  , _incomePage_totalCount :: Int
+  } deriving (Eq, Show, Generic)
+
+instance FromJSON IncomePage
+instance ToJSON IncomePage
diff --git a/common/src/Common/Model/Init.hs b/common/src/Common/Model/Init.hs
new file mode 100644
index 0000000..5ef1535
--- /dev/null
+++ b/common/src/Common/Model/Init.hs
@@ -0,0 +1,18 @@
+module Common.Model.Init
+  ( Init(..)
+  ) where
+
+import           Data.Aeson            (FromJSON, ToJSON)
+import           GHC.Generics          (Generic)
+
+import           Common.Model.Currency (Currency)
+import           Common.Model.User     (User, UserId)
+
+data Init = Init
+  { _init_users       :: [User]
+  , _init_currentUser :: UserId
+  , _init_currency    :: Currency
+  } deriving (Show, Generic)
+
+instance FromJSON Init
+instance ToJSON Init
diff --git a/common/src/Common/Model/Password.hs b/common/src/Common/Model/Password.hs
new file mode 100644
index 0000000..1b51a47
--- /dev/null
+++ b/common/src/Common/Model/Password.hs
@@ -0,0 +1,12 @@
+module Common.Model.Password
+  ( Password(..)
+  ) where
+
+import           Data.Aeson   (FromJSON, ToJSON)
+import           Data.Text    (Text)
+import           GHC.Generics (Generic)
+
+newtype Password = Password Text deriving (Show, Generic)
+
+instance FromJSON Password
+instance ToJSON Password
diff --git a/common/src/Common/Model/Payment.hs b/common/src/Common/Model/Payment.hs
new file mode 100644
index 0000000..733a145
--- /dev/null
+++ b/common/src/Common/Model/Payment.hs
@@ -0,0 +1,33 @@
+module Common.Model.Payment
+  ( PaymentId
+  , Payment(..)
+  ) where
+
+import           Data.Aeson             (FromJSON, ToJSON)
+import           Data.Int               (Int64)
+import           Data.Text              (Text)
+import           Data.Time              (UTCTime)
+import           Data.Time.Calendar     (Day)
+import           GHC.Generics           (Generic)
+
+import           Common.Model.Category  (CategoryId)
+import           Common.Model.Frequency
+import           Common.Model.User      (UserId)
+
+type PaymentId = Int64
+
+data Payment = Payment
+  { _payment_id        :: PaymentId
+  , _payment_user      :: UserId
+  , _payment_name      :: Text
+  , _payment_cost      :: Int
+  , _payment_date      :: Day
+  , _payment_category  :: CategoryId
+  , _payment_frequency :: Frequency
+  , _payment_createdAt :: UTCTime
+  , _payment_editedAt  :: Maybe UTCTime
+  , _payment_deletedAt :: Maybe UTCTime
+  } deriving (Eq, Show, Generic)
+
+instance FromJSON Payment
+instance ToJSON Payment
diff --git a/common/src/Common/Model/PaymentHeader.hs b/common/src/Common/Model/PaymentHeader.hs
new file mode 100644
index 0000000..35f5e1a
--- /dev/null
+++ b/common/src/Common/Model/PaymentHeader.hs
@@ -0,0 +1,18 @@
+module Common.Model.PaymentHeader
+  ( PaymentHeader(..)
+  ) where
+
+import           Data.Aeson                  (FromJSON, ToJSON)
+import           Data.Map                    (Map)
+import           GHC.Generics                (Generic)
+
+import           Common.Model.ExceedingPayer (ExceedingPayer)
+import           Common.Model.User           (UserId)
+
+data PaymentHeader = PaymentHeader
+  { _paymentHeader_exceedingPayers :: [ExceedingPayer]
+  , _paymentHeader_repartition     :: Map UserId Int
+  } deriving (Eq, Show, Generic)
+
+instance FromJSON PaymentHeader
+instance ToJSON PaymentHeader
diff --git a/common/src/Common/Model/PaymentPage.hs b/common/src/Common/Model/PaymentPage.hs
new file mode 100644
index 0000000..88d9715
--- /dev/null
+++ b/common/src/Common/Model/PaymentPage.hs
@@ -0,0 +1,21 @@
+module Common.Model.PaymentPage
+  ( PaymentPage(..)
+  ) where
+
+import           Data.Aeson                 (FromJSON, ToJSON)
+import           GHC.Generics               (Generic)
+
+import           Common.Model.Frequency     (Frequency)
+import           Common.Model.Payment       (Payment)
+import           Common.Model.PaymentHeader (PaymentHeader)
+
+data PaymentPage = PaymentPage
+  { _paymentPage_page       :: Int
+  , _paymentPage_frequency  :: Frequency
+  , _paymentPage_header     :: PaymentHeader
+  , _paymentPage_payments   :: [Payment]
+  , _paymentPage_totalCount :: Int
+  } deriving (Eq, Show, Generic)
+
+instance FromJSON PaymentPage
+instance ToJSON PaymentPage
diff --git a/common/src/Common/Model/SignInForm.hs b/common/src/Common/Model/SignInForm.hs
new file mode 100644
index 0000000..7a25935
--- /dev/null
+++ b/common/src/Common/Model/SignInForm.hs
@@ -0,0 +1,15 @@
+module Common.Model.SignInForm
+  ( SignInForm(..)
+  ) where
+
+import           Data.Aeson   (FromJSON, ToJSON)
+import           Data.Text    (Text)
+import           GHC.Generics (Generic)
+
+data SignInForm = SignInForm
+  { _signInForm_email    :: Text
+  , _signInForm_password :: Text
+  } deriving (Show, Generic)
+
+instance FromJSON SignInForm
+instance ToJSON SignInForm
diff --git a/common/src/Common/Model/Stats.hs b/common/src/Common/Model/Stats.hs
new file mode 100644
index 0000000..86e6ab9
--- /dev/null
+++ b/common/src/Common/Model/Stats.hs
@@ -0,0 +1,23 @@
+module Common.Model.Stats
+  ( Stats
+  , MonthStats(..)
+  ) where
+
+import           Data.Aeson            (FromJSON, ToJSON)
+import           Data.Map              (Map)
+import           Data.Time.Calendar    (Day)
+import           GHC.Generics          (Generic)
+
+import           Common.Model.Category (CategoryId)
+import           Common.Model.User     (UserId)
+
+type Stats = [MonthStats]
+
+data MonthStats = MonthStats
+  { _monthStats_start              :: Day
+  , _monthStats_paymentsByCategory :: Map CategoryId Int
+  , _monthStats_incomeByUser       :: Map UserId Int
+  } deriving (Eq, Show, Generic)
+
+instance FromJSON MonthStats
+instance ToJSON MonthStats
diff --git a/common/src/Common/Model/User.hs b/common/src/Common/Model/User.hs
new file mode 100644
index 0000000..a30d104
--- /dev/null
+++ b/common/src/Common/Model/User.hs
@@ -0,0 +1,27 @@
+module Common.Model.User
+  ( UserId
+  , User(..)
+  , findUser
+  ) where
+
+import           Data.Aeson   (FromJSON, ToJSON)
+import           Data.Int     (Int64)
+import qualified Data.List    as L
+import           Data.Text    (Text)
+import           Data.Time    (UTCTime)
+import           GHC.Generics (Generic)
+
+type UserId = Int64
+
+data User = User
+  { _user_id       :: UserId
+  , _user_creation :: UTCTime
+  , _user_email    :: Text
+  , _user_name     :: Text
+  } deriving (Show, Generic)
+
+instance FromJSON User
+instance ToJSON User
+
+findUser :: UserId -> [User] -> Maybe User
+findUser userId users = L.find ((== userId) . _user_id) users
diff --git a/common/src/Common/Msg.hs b/common/src/Common/Msg.hs
new file mode 100644
index 0000000..9e4cfe2
--- /dev/null
+++ b/common/src/Common/Msg.hs
@@ -0,0 +1,13 @@
+module Common.Msg
+  ( get
+  , Key(..)
+  ) where
+
+import           Data.Text                  (Text)
+
+import           Common.Message.Key         (Key (..))
+import           Common.Message.Lang        (Lang (..))
+import qualified Common.Message.Translation as Translation
+
+get :: Key -> Text
+get = Translation.get French
diff --git a/common/src/Common/Util/Text.hs b/common/src/Common/Util/Text.hs
new file mode 100644
index 0000000..0f9c187
--- /dev/null
+++ b/common/src/Common/Util/Text.hs
@@ -0,0 +1,49 @@
+module Common.Util.Text
+  ( search
+  , formatSearch
+  , unaccent
+  ) where
+
+import           Data.Text (Text)
+import qualified Data.Text as T
+
+search :: Text -> Text -> Bool
+search s t = (formatSearch s) `T.isInfixOf` (formatSearch t)
+
+formatSearch :: Text -> Text
+formatSearch = T.toLower . unaccent
+
+unaccent :: Text -> Text
+unaccent = T.map unaccentChar
+
+unaccentChar :: Char -> Char
+unaccentChar c = case c of
+  'à' -> 'a'
+  'á' -> 'a'
+  'â' -> 'a'
+  'ã' -> 'a'
+  'ä' -> 'a'
+  'ç' -> 'c'
+  'è' -> 'e'
+  'é' -> 'e'
+  'ê' -> 'e'
+  'ë' -> 'e'
+  'ì' -> 'i'
+  'í' -> 'i'
+  'î' -> 'i'
+  'ï' -> 'i'
+  'ñ' -> 'n'
+  'ò' -> 'o'
+  'ó' -> 'o'
+  'ô' -> 'o'
+  'õ' -> 'o'
+  'ö' -> 'o'
+  'š' -> 's'
+  'ù' -> 'u'
+  'ú' -> 'u'
+  'û' -> 'u'
+  'ü' -> 'u'
+  'ý' -> 'y'
+  'ÿ' -> 'y'
+  'ž' -> 'z'
+  _   -> c
diff --git a/common/src/Common/Util/Time.hs b/common/src/Common/Util/Time.hs
new file mode 100644
index 0000000..6240720
--- /dev/null
+++ b/common/src/Common/Util/Time.hs
@@ -0,0 +1,26 @@
+module Common.Util.Time
+  ( timeToDay
+  , parseDay
+  ) where
+
+import           Data.Text           (Text)
+import qualified Data.Text           as T
+import           Data.Time           (UTCTime)
+import qualified Data.Time           as Time
+import           Data.Time.Calendar  (Day)
+import           Data.Time.LocalTime
+import qualified Text.Read           as T
+
+timeToDay :: UTCTime -> IO Day
+timeToDay time = localDay . (flip utcToLocalTime time) <$> getTimeZone time
+
+parseDay :: Text -> Maybe Day
+parseDay str = do
+  (y, m, d) <-
+    case T.splitOn "-" str of
+      [y, m, d] -> Just (y, m, d)
+      _         -> Nothing
+  d' <- T.readMaybe . T.unpack $ d
+  m' <- T.readMaybe . T.unpack $ m
+  y' <- T.readMaybe . T.unpack $ y
+  return $ Time.fromGregorian y' m' d'
diff --git a/common/src/Common/Util/Validation.hs b/common/src/Common/Util/Validation.hs
new file mode 100644
index 0000000..f195d95
--- /dev/null
+++ b/common/src/Common/Util/Validation.hs
@@ -0,0 +1,13 @@
+module Common.Util.Validation
+  ( isSuccess
+  , isFailure
+  ) where
+
+import           Data.Validation (Validation (Failure, Success))
+
+isSuccess :: forall a b. Validation a b -> Bool
+isSuccess (Failure _) = False
+isSuccess (Success _) = True
+
+isFailure :: forall a b. Validation a b -> Bool
+isFailure = not . isSuccess
diff --git a/common/src/Common/Validation/Atomic.hs b/common/src/Common/Validation/Atomic.hs
new file mode 100644
index 0000000..9c21e14
--- /dev/null
+++ b/common/src/Common/Validation/Atomic.hs
@@ -0,0 +1,61 @@
+module Common.Validation.Atomic
+  ( color
+  , day
+  , minLength
+  , nonEmpty
+  , nonNullNumber
+  , number
+  , password
+  ) where
+
+import qualified Data.Char          as Char
+import           Data.Text          (Text)
+import qualified Data.Text          as T
+import           Data.Time.Calendar (Day)
+import           Data.Validation    (Validation)
+import qualified Data.Validation    as V
+import qualified Text.Read          as T
+
+import qualified Common.Msg         as Msg
+import qualified Common.Util.Time   as Time
+
+minLength :: Int -> Text -> Validation Text Text
+minLength l =
+  V.validate
+    (Msg.get (Msg.Form_MinChars l))
+    (\t -> if T.length t >= l then Just t else Nothing)
+
+nonEmpty :: Text -> Validation Text Text
+nonEmpty =
+  V.validate
+    (Msg.get Msg.Form_NonEmpty)
+    (\t -> if (not . T.null $ t) then Just t else Nothing)
+
+number :: Text -> Validation Text Int
+number input =
+  case (T.readMaybe . T.unpack $ input) of
+    Just n -> V.Success n
+    _      -> V.Failure (Msg.get Msg.Form_InvalidInt)
+
+nonNullNumber :: Int -> Validation Text Int
+nonNullNumber =
+  V.validate
+    (Msg.get Msg.Form_NonNullNumber)
+    (\n -> if n /= 0 then Just n else Nothing)
+
+day :: Text ->  Validation Text Day
+day str =
+  case Time.parseDay str of
+    Just d  -> V.Success d
+    Nothing -> V.Failure $ Msg.get Msg.Form_InvalidDate
+
+color :: Text -> Validation Text Text
+color str =
+  if T.take 1 str == "#" && T.all Char.isHexDigit (T.drop 1 str) then
+    V.Success str
+
+  else
+    V.Failure (Msg.get Msg.Form_InvalidColor)
+
+password :: Text -> Validation Text Text
+password = minLength 8
diff --git a/common/src/Common/Validation/Category.hs b/common/src/Common/Validation/Category.hs
new file mode 100644
index 0000000..f9e6ab4
--- /dev/null
+++ b/common/src/Common/Validation/Category.hs
@@ -0,0 +1,15 @@
+module Common.Validation.Category
+  ( name
+  , color
+  ) where
+
+import           Data.Text                (Text)
+import           Data.Validation          (Validation)
+
+import qualified Common.Validation.Atomic as Atomic
+
+name :: Text -> Validation Text Text
+name = Atomic.nonEmpty
+
+color :: Text -> Validation Text Text
+color = Atomic.color
diff --git a/common/src/Common/Validation/Income.hs b/common/src/Common/Validation/Income.hs
new file mode 100644
index 0000000..7a58bab
--- /dev/null
+++ b/common/src/Common/Validation/Income.hs
@@ -0,0 +1,17 @@
+module Common.Validation.Income
+  ( amount
+  , date
+  ) where
+
+import           Data.Text                (Text)
+import           Data.Time.Calendar       (Day)
+import           Data.Validation          (Validation)
+import qualified Data.Validation          as V
+
+import qualified Common.Validation.Atomic as Atomic
+
+amount :: Text -> Validation Text Int
+amount input = V.bindValidation (Atomic.number input) Atomic.nonNullNumber
+
+date :: Text -> Validation Text Day
+date = Atomic.day
diff --git a/common/src/Common/Validation/Payment.hs b/common/src/Common/Validation/Payment.hs
new file mode 100644
index 0000000..e3c447a
--- /dev/null
+++ b/common/src/Common/Validation/Payment.hs
@@ -0,0 +1,31 @@
+module Common.Validation.Payment
+  ( name
+  , cost
+  , date
+  , category
+  ) where
+
+import           Data.Text                (Text)
+import           Data.Time.Calendar       (Day)
+import           Data.Validation          (Validation)
+import qualified Data.Validation          as V
+
+import           Common.Model             (CategoryId)
+import qualified Common.Msg               as Msg
+import qualified Common.Validation.Atomic as Atomic
+
+name :: Text -> Validation Text Text
+name = Atomic.nonEmpty
+
+cost :: Text -> Validation Text Int
+cost input = V.bindValidation (Atomic.number input) Atomic.nonNullNumber
+
+date :: Text -> Validation Text Day
+date = Atomic.day
+
+category :: [CategoryId] -> CategoryId -> Validation Text CategoryId
+category cs c =
+  if elem c cs then
+    V.Success c
+  else
+    V.Failure $ Msg.get Msg.Form_InvalidCategory
diff --git a/common/src/Common/Validation/SignIn.hs b/common/src/Common/Validation/SignIn.hs
new file mode 100644
index 0000000..ac9cc37
--- /dev/null
+++ b/common/src/Common/Validation/SignIn.hs
@@ -0,0 +1,17 @@
+module Common.Validation.SignIn
+  ( email
+  , password
+  ) where
+
+import           Data.Text                (Text)
+import           Data.Validation          (Validation)
+
+import           Common.Model.Email       (Email (..))
+import           Common.Model.Password    (Password (..))
+import qualified Common.Validation.Atomic as Atomic
+
+email :: Text -> Validation Text Email
+email = fmap Email . Atomic.minLength 5
+
+password :: Text -> Validation Text Password
+password = fmap Password . Atomic.minLength 8
diff --git a/common/src/Common/View/Format.hs b/common/src/Common/View/Format.hs
new file mode 100644
index 0000000..5d879fa
--- /dev/null
+++ b/common/src/Common/View/Format.hs
@@ -0,0 +1,78 @@
+module Common.View.Format
+  ( shortDay
+  , longDay
+  , price
+  , number
+  , monthAndYear
+  ) where
+
+import qualified Data.List          as L
+import qualified Data.Maybe         as Maybe
+import           Data.Text          (Text)
+import qualified Data.Text          as T
+import           Data.Time.Calendar (Day)
+import qualified Data.Time.Calendar as Calendar
+
+import           Common.Model       (Currency (..))
+import           Common.Msg         (Key)
+import qualified Common.Msg         as Msg
+
+shortDay :: Day -> Text
+shortDay date =
+  Msg.get $ Msg.Date_Short
+    day
+    month
+    (fromIntegral year)
+  where (year, month, day) = Calendar.toGregorian date
+
+longDay :: Day -> Text
+longDay date =
+  Msg.get $ Msg.Date_Long
+    day
+    (Maybe.fromMaybe "−" . fmap Msg.get . monthToKey $ month)
+    (fromIntegral year)
+  where (year, month, day) = Calendar.toGregorian date
+
+monthAndYear :: Day -> Text
+monthAndYear date =
+  T.intercalate " "
+    [ Maybe.fromMaybe "" . fmap ((\t -> T.concat [t, " "]) . Msg.get) . monthToKey $ month
+    , T.pack . show $ year
+    ]
+  where (year, month, _) = Calendar.toGregorian date
+
+monthToKey :: Int -> Maybe Key
+monthToKey 1  = Just Msg.Month_January
+monthToKey 2  = Just Msg.Month_February
+monthToKey 3  = Just Msg.Month_March
+monthToKey 4  = Just Msg.Month_April
+monthToKey 5  = Just Msg.Month_May
+monthToKey 6  = Just Msg.Month_June
+monthToKey 7  = Just Msg.Month_July
+monthToKey 8  = Just Msg.Month_August
+monthToKey 9  = Just Msg.Month_September
+monthToKey 10 = Just Msg.Month_October
+monthToKey 11 = Just Msg.Month_November
+monthToKey 12 = Just Msg.Month_December
+monthToKey _  = Nothing
+
+price :: Currency -> Int -> Text
+price (Currency currency) amount = T.concat [ number amount, " ", currency ]
+
+number :: Int -> Text
+number n =
+  T.pack
+  . (++) (if n < 0 then "-" else "")
+  . reverse
+  . concat
+  . L.intersperse " "
+  . group 3
+  . reverse
+  . show
+  . abs $ n
+
+group :: Int -> [a] -> [[a]]
+group n xs =
+  if length xs <= n
+    then [xs]
+    else (take n xs) : (group n (drop n xs))