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

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

header_labels = ["Age", "Name", "Duration", "Difficulty", "Priority", "Tag"]

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

        super().__init__(parent)

        self.init_state()
        self.sort()

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

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

        # Menu
        self.setContextMenuPolicy(Qt.CustomContextMenu)
        self.customContextMenuRequested.connect(lambda position: gui.tasks.table.menu.open(self, 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 on_show(self):
        self._tags = db.tags.get(database.cursor())
        self.update_view()

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


    def init_header(self):
        h = QtWidgets.QHeaderView(Qt.Horizontal, self)
        self._header_model = QtGui.QStandardItemModel()
        self._header_model.setHorizontalHeaderLabels(header_labels)
        h.setModel(self._header_model)
        h.setSectionsClickable(True)
        h.sectionClicked.connect(self.on_header_click)
        self.setHorizontalHeader(h)
        # header.setSectionResizeMode(2, QtWidgets.QHeaderView.ResizeToContents)

    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.setItem(column, QtGui.QStandardItem('Hey!'))
        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]):
        # TODO: just update if sort order is not impacted
        # self._tasks[row] = task
        # task_ids = [t.id for t in self._tasks]
        # filtred_task_tags = [tt for tt in self._task_tags if tt.task_id in task_ids]
        # 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
        # self.update_row(row)
        self.delete_rows([row])
        row = self.insert(task, tags)
        self.selectRow(row)

    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)))
        self.setItem(row, 1, item(task.name))
        self.setCellWidget(row, 2, colored_label(self, gui.tasks.duration.format(task.duration), 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, 45)

    def insert(self, task: Task, tags: List[int]) -> int:
        is_rev = self.is_reversed()
        row = 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._task_tags += [TaskTag(task_id=task.id, tag_id=tag_id) for tag_id in tags]
        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)
                gui.tasks.dialog.update(self, self._update_task_signal, row, task, tags).exec_()
        elif event.key() == Qt.Key_Delete:
            rows = self.get_selected_rows()
            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]
        service.tasks.delete(database.cursor(), task_ids)
        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]]
        for row in sorted(rows, reverse=True):
            self.removeRow(row)

    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)
        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 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 gui.color.easy_difficulty
    elif d == Difficulty.NORMAL:
        return gui.color.normal_difficulty
    elif d == Difficulty.HARD:
        return gui.color.hard_difficulty

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