from PyQt5 import QtWidgets, QtCore, QtGui
from PyQt5.QtCore import Qt
from typing import List, Tuple
import time
import math

from todo.model import difficulty, priority
from todo.model.difficulty import Difficulty
from todo.model.priority import Priority
from todo.model.tag import Tag
from todo.model.task import Task
from todo.model.task_tag import TaskTag
from todo.model.status import Status
import todo.database
import todo.db.tags
import todo.db.task_tags
import todo.gui.color
import todo.gui.signal
import todo.gui.tasks.dialog
import todo.gui.tasks.duration
import todo.gui.tasks.signal
import todo.gui.tasks.signal
import todo.gui.tasks.table.menu
import todo.service.tasks
import todo.util.array

class Widget(QtWidgets.QTableWidget):
    def __init__(
            self,
            parent,
            on_show: todo.gui.signal.Reload,
            add_task_signal: todo.gui.tasks.signal.AddTask,
            status: Status):
        super().__init__(parent)

        self.init_state(status)
        self.sort()

        self.setSelectionBehavior(QtWidgets.QTableView.SelectRows)
        self.init_header()
        self.setRowCount(len(self._tasks))
        self.setColumnCount(len(self.header_labels()))
        self.setColumnWidth(1, 500)

        self.update_view()
        self.horizontalHeader().setStretchLastSection(True)

        # Menu
        self.setContextMenuPolicy(Qt.CustomContextMenu)
        self.customContextMenuRequested.connect(lambda position: todo.gui.tasks.table.menu.open(self, status, self._update_task_signal, position))

        self.doubleClicked.connect(lambda index: self.on_double_click(index.row()))
        add_task_signal.connect(lambda task, tags: self.insert(task, tags))
        self._update_task_signal.connect(lambda row, task, tags: self.update_task(row, task, tags))
        on_show.connect(lambda: self.on_show())

    def init_state(self, status: Status):
        self._update_task_signal = todo.gui.tasks.signal.UpdateTask()
        cursor = todo.database.cursor()
        self._status = status
        self._tasks = todo.service.tasks.get(cursor, self._status)
        self._task_tags = todo.db.task_tags.get(cursor)
        self._tags = todo.db.tags.get(cursor)
        self._sort_column = 0
        self._sort_is_ascending = True

    def init_header(self):
        self._header_view = QtWidgets.QHeaderView(Qt.Horizontal, self)
        self._header_model = QtGui.QStandardItemModel()
        self._header_model.setHorizontalHeaderLabels(self.header_labels())
        self._header_view.setModel(self._header_model)
        self._header_view.setSectionsClickable(True)
        self._header_view.sectionClicked.connect(self.on_header_click)
        self.setHorizontalHeader(self._header_view)

    def on_show(self):
        cursor = todo.database.cursor()
        self._tasks = todo.service.tasks.get(cursor, self._status)
        self._task_tags = todo.db.task_tags.get(cursor)
        self._tags = todo.db.tags.get(cursor)
        self.setRowCount(len(self._tasks))
        self.sort()
        self.update_view()

    def on_header_click(self, column):
        if self._sort_column == column:
            self._sort_is_ascending = not self._sort_is_ascending
        else:
            self._sort_is_ascending = True
        self._sort_column = column
        self.sort()
        self._header_model.setHorizontalHeaderLabels(self.header_labels())
        self.update_view()

    def sort(self):
        is_rev = self.is_reversed()
        self._tasks = sorted(
                self._tasks,
                key = lambda task: self.sort_key(task, is_rev),
                reverse = is_rev)

    def update_task(self, row, task: Task, tags: List[int]):
        self._tasks[row] = task
        filtred_task_tags = [tt for tt in self._task_tags if tt.task_id in [t.id for t in self._tasks if t.id != task.id]]
        new_task_tags = [TaskTag(task_id=task.id, tag_id=tag_id) for tag_id in tags]
        self._task_tags = filtred_task_tags + new_task_tags

        # Update task in table
        self.sort()
        row_after_sort = [i for i in range(len(self._tasks)) if self._tasks[i].id == task.id][0]
        if row_after_sort == row:
            self.update_row(row)
        else:
            self.removeRow(row)
            self.insertRow(row_after_sort)
            self.update_row(row_after_sort)
            self.selectRow(row_after_sort)

    def update_view(self):
        for row in range(len(self._tasks)):
            self.update_row(row)

    def update_row(self, row: int):
        task = self._tasks[row]
        self.setItem(row, 0, item(age_since(task.created_at)))
        if task.description:
            name = task.name + " *"
        else:
            name = task.name
        self.setItem(row, 1, item(name))
        self.setCellWidget(row, 2, colored_label(self, todo.gui.tasks.duration.format(task.duration), todo.gui.tasks.duration.color(task.duration)))
        self.setCellWidget(row, 3, colored_label(self, difficulty.format(task.difficulty), difficulty_color(task.difficulty)))
        self.setCellWidget(row, 4, colored_label(self, priority.format(task.priority), priority_color(task.priority)))
        tag_ids = [tt.tag_id for tt in self._task_tags if tt.task_id == task.id]
        res_tags = sorted([tag for tag in self._tags if tag.id in tag_ids], key=lambda t: t.name)
        self.setCellWidget(row, 5, render_tags(self, res_tags))
        self.setRowHeight(row, 50)

    def insert(self, task: Task, tags: List[int]) -> int:
        is_rev = self.is_reversed()
        row = todo.util.array.insert_position(
                self.sort_key(task, is_rev),
                [self.sort_key(t, is_rev) for t in self._tasks],
                is_rev)
        self._tasks.insert(row, task)
        self._task_tags += [TaskTag(task_id=task.id, tag_id=tag_id) for tag_id in tags]
        self.insertRow(row)
        self.update_row(row)
        self.setRowCount(len(self._tasks))
        return row

    def is_reversed(self) -> bool:
        if self._sort_column == 0:
            return self._sort_is_ascending
        else:
            return not self._sort_is_ascending

    def sort_key(self, task: Task, is_reversed: bool):
        row = self._sort_column
        if row == 0:
            return task.created_at
        elif row == 1:
            return task.name.lower()
        elif row == 2:
            if is_reversed:
                return task.duration
            else:
                return (task.duration == 0, task.duration)
        elif row == 3:
            return task.difficulty
        elif row == 4:
            return task.priority
        elif row == 5:
            tag_ids = [tt.tag_id for tt in self._task_tags if tt.task_id == task.id]
            tags = sorted([tag.name.lower() for tag in self._tags if tag.id in tag_ids])
            key = "".join(tags)
            if is_reversed:
                return key
            else:
                return (key == "", key)

    def keyPressEvent(self, event):
        super().keyPressEvent(event)
        if event.key() in (Qt.Key_Return, Qt.Key_Enter):
            rows = self.get_selected_rows()
            if len(rows) == 1:
                row = rows[0]
                (task, tags) = self.get_at(row)
                todo.gui.tasks.dialog.update(self, self._update_task_signal, row, task, tags).exec_()
        elif event.key() == Qt.Key_Delete:
            rows = self.get_selected_rows()
            todo.gui.tasks.dialog.show_delete(self, rows, lambda: self.delete_rows(rows))

    def delete_rows(self, rows: List[int]):
        task_ids = [task.id for i, task in enumerate(self._tasks) if i in rows]
        todo.service.tasks.delete(todo.database.cursor(), task_ids)
        self.remove_rows_from_table(rows, task_ids)

    def update_status(self, rows: List[int], status: Status):
        task_ids = [task.id for i, task in enumerate(self._tasks) if i in rows]
        todo.service.tasks.update_status(todo.database.cursor(), task_ids, status)
        self.remove_rows_from_table(rows, task_ids)

    def remove_rows_from_table(self, rows: List[int], task_ids: List[int]):
        for row in sorted(rows, reverse=True):
            self.removeRow(row)
        self._tasks = [t for t in self._tasks if t.id not in task_ids]
        self._task_tags = [tt for tt in self._task_tags if tt.task_id in [t.id for t in self._tasks]]
        self.setRowCount(len(self._tasks))

    def get_selected_rows(self):
        return list(set([index.row() for index in self.selectedIndexes()]))

    def on_double_click(self, row: int):
        (task, tags) = self.get_at(row)
        todo.gui.tasks.dialog.update(self, self._update_task_signal, row, task, tags).exec_()

    def get_at(self, row: int) -> Tuple[Task, List[int]]:
        task = self._tasks[row]
        tags = [tt.tag_id for tt in self._task_tags if tt.task_id == task.id]
        return (task, tags)

    def header_labels(self):
        labels = ["Age", "Name", "Duration", "Difficulty", "Priority", "Tag"]
        if self._sort_is_ascending:
            sign = "▼"
        else:
            sign = "▲"
        labels[self._sort_column] = labels[self._sort_column] + " " + sign
        return labels

def item(text: str):
    item = QtWidgets.QTableWidgetItem(text)
    item.setFlags(Qt.ItemIsSelectable | Qt.ItemIsEnabled)
    return item

def age_since(timestamp):
    diff = int(time.time()) - timestamp
    if diff >= 60 * 60 * 24:
        return "" + str(math.floor(diff / 60 / 60 / 24)) + "d"
    elif diff >= 60 * 60:
        return "" + str(math.floor(diff / 60 / 60)) + "h"
    elif diff >= 60:
        return "" + str(math.floor(diff / 60)) + "m"
    else:
        return "1m"

def colored_label(parent, text: str, color: QtGui.QColor):
    label = QtWidgets.QLabel(text)
    palette = QtGui.QPalette()
    palette.setColor(QtGui.QPalette.Text, color)
    label.setPalette(palette)
    return label

def render_tags(parent, tags: List[Tag]):
    widget = QtWidgets.QWidget(parent)

    layout = QtWidgets.QHBoxLayout(widget)
    widget.setLayout(layout)

    for tag in tags:
        label = QtWidgets.QLabel(tag.name)
        label.setContentsMargins(3, 3, 3, 3)
        palette = QtGui.QPalette()
        palette.setColor(QtGui.QPalette.Base, QtGui.QColor(tag.color))
        label.setAutoFillBackground(True)
        label.setPalette(palette)
        layout.addWidget(label)

    return widget

def difficulty_color(d: Difficulty) -> QtGui.QColor:
    if d == Difficulty.EASY:
        return todo.gui.color.easy_difficulty
    elif d == Difficulty.NORMAL:
        return todo.gui.color.normal_difficulty
    elif d == Difficulty.HARD:
        return todo.gui.color.hard_difficulty

def priority_color(p: Priority) -> QtGui.QColor:
    if p == Priority.LOW:
        return todo.gui.color.low_priority
    elif p == Priority.MIDDLE:
        return todo.gui.color.middle_priority
    elif p == Priority.HIGH:
        return todo.gui.color.high_priority