<template>
	<div class="gantt-chart box">
		<div class="filter-container">
			<div class="items">
				<button @click="showTaskFilter = !showTaskFilter" class="button">
					<span class="icon is-small">
						<icon icon="filter"/>
					</span>
					Filters
				</button>
			</div>
			<transition name="fade">
				<filters
					@change="loadTasks"
					v-if="showTaskFilter"
					v-model="params"
				/>
			</transition>
		</div>
		<div class="dates">
			<template v-for="(y, yk) in days">
				<div :key="yk + 'year'" class="months">
					<div :key="mk + 'month'" class="month" v-for="(m, mk) in days[yk]">
						{{ new Date((new Date(yk)).setMonth(mk)).toLocaleString('en-us', {month: 'long'}) }},
						{{ (new Date(yk)).getFullYear() }}
						<div class="days">
							<div
								:class="{'today': d.toDateString() === now.toDateString()}"
								:key="dk + 'day'"
								:style="{'width': dayWidth + 'px'}"
								class="day"
								v-for="(d, dk) in days[yk][mk]">
								<span class="theday" v-if="dayWidth > 25">
									{{ d.getDate() }}
								</span>
								<span class="weekday" v-if="dayWidth > 25">
									{{ d.toLocaleString('en-us', {weekday: 'short'}) }}
								</span>
							</div>
						</div>
					</div>
				</div>
			</template>
		</div>
		<div :style="{'width': fullWidth + 'px'}" class="tasks">
			<div
				:key="t.id"
				:style="{background: 'repeating-linear-gradient(90deg, #ededed, #ededed 1px, ' + (k % 2 === 0 ? '#fafafa 1px, #fafafa ' : '#fff 1px, #fff ') + dayWidth + 'px)'}"
				class="row"
				v-for="(t, k) in theTasks">
				<VueDragResize
					:class="{
							'done': t.done,
							'is-current-edit': taskToEdit !== null && taskToEdit.id === t.id,
							'has-light-text': !colorIsDark(t.hexColor),
							'has-dark-text': colorIsDark(t.hexColor)
						}"
					:gridX="dayWidth"
					:h="31"
					:isActive="canWrite"
					:minw="dayWidth"
					:parentLimitation="true"
					:parentW="fullWidth"
					:snapToGrid="true"
					:sticks="['mr', 'ml']"
					:style="{'border-color': t.hexColor, 'background-color': t.hexColor}"
					:w="t.durationDays * dayWidth"
					:x="t.offsetDays * dayWidth - 6"
					:y="0"
					@clicked="setTaskDragged(t)"
					@dragstop="resizeTask"
					@resizestop="resizeTask"
					axis="x"
					class="task"
				>
					<span :class="{
					'has-high-priority': t.priority >= priorities.HIGH,
					'has-not-so-high-priority': t.priority === priorities.HIGH,
					'has-super-high-priority': t.priority === priorities.DO_NOW
					}">{{ t.title }}</span>
					<priority-label :priority="t.priority"/>
					<!-- using the key here forces vue to use the updated version model and not the response returned by the api -->
					<a @click="editTask(theTasks[k])" class="edit-toggle">
						<icon icon="pen"/>
					</a>
				</VueDragResize>
			</div>
			<template v-if="showTaskswithoutDates">
				<div
					:key="t.id"
					:style="{background: 'repeating-linear-gradient(90deg, #ededed, #ededed 1px, ' + (k % 2 === 0 ? '#fafafa 1px, #fafafa ' : '#fff 1px, #fff ') + dayWidth + 'px)'}"
					class="row"
					v-for="(t, k) in tasksWithoutDates">
					<VueDragResize
						:gridX="dayWidth"
						:h="31"
						:isActive="canWrite"
						:minw="dayWidth"
						:parentLimitation="true"
						:parentW="fullWidth"
						:snapToGrid="true"
						:sticks="['mr', 'ml']"
						:x="dayOffsetUntilToday * dayWidth - 6"
						:y="0"
						@clicked="setTaskDragged(t)"
						@dragstop="resizeTask"
						@resizestop="resizeTask"
						axis="x"
						class="task nodate"
						v-tooltip="'This task has no dates set.'"
					>
						<span>{{ t.title }}</span>
					</VueDragResize>
				</div>
			</template>
		</div>
		<form @submit.prevent="addNewTask()" class="add-new-task" v-if="canWrite">
			<transition name="width">
				<input
					@blur="hideCrateNewTask"
					@keyup.esc="newTaskFieldActive = false"
					class="input"
					ref="newTaskTitleField"
					type="text"
					v-if="newTaskFieldActive"
					v-model="newTaskTitle"
				/>
			</transition>
			<button @click="showCreateNewTask" class="button is-primary noshadow">
				<span class="icon is-small">
					<icon icon="plus"/>
				</span>
				Add a new task
			</button>
		</form>
		<transition name="fade">
			<div class="card taskedit" v-if="isTaskEdit">
				<header class="card-header">
					<p class="card-header-title">
						Edit Task
					</p>
					<a @click="() => {isTaskEdit = false; taskToEdit = null}" class="card-header-icon">
						<span class="icon">
							<icon icon="times"/>
						</span>
					</a>
				</header>
				<div class="card-content">
					<div class="content">
						<edit-task :task="taskToEdit"/>
					</div>
				</div>
			</div>
		</transition>
	</div>
</template>

<script>
import VueDragResize from 'vue-drag-resize'
import EditTask from './edit-task'

import TaskService from '../../services/task'
import TaskModel from '../../models/task'
import priorities from '../../models/priorities'
import PriorityLabel from './partials/priorityLabel'
import TaskCollectionService from '../../services/taskCollection'
import {mapState} from 'vuex'
import Rights from '../../models/rights.json'
import Filters from '@/components/list/partials/filters'

export default {
	name: 'GanttChart',
	components: {
		Filters,
		PriorityLabel,
		EditTask,
		VueDragResize,
	},
	props: {
		listId: {
			type: Number,
			required: true,
		},
		showTaskswithoutDates: {
			type: Boolean,
			default: false,
		},
		dateFrom: {
			default: new Date((new Date()).setDate((new Date()).getDate() - 15)),
		},
		dateTo: {
			default: new Date((new Date()).setDate((new Date()).getDate() + 30)),
		},
		// The width of a day in pixels, used to calculate all sorts of things.
		dayWidth: {
			type: Number,
			default: 35,
		},
	},
	data() {
		return {
			days: [],
			startDate: null,
			endDate: null,
			theTasks: [], // Pretty much a copy of the prop, since we cant mutate the prop directly
			tasksWithoutDates: [],
			taskService: TaskService,
			taskDragged: null, // Saves to currently dragged task to be able to update it
			fullWidth: 0,
			now: null,
			dayOffsetUntilToday: 0,
			isTaskEdit: false,
			taskToEdit: null,
			newTaskTitle: '',
			newTaskFieldActive: false,
			priorities: {},
			taskCollectionService: TaskCollectionService,
			showTaskFilter: false,

			params: {
				sort_by: ['done', 'id'],
				order_by: ['asc', 'desc'],
				filter_by: ['done'],
				filter_value: ['false'],
				filter_comparator: ['equals'],
				filter_concat: 'and',
			},
		}
	},
	watch: {
		'dateFrom': 'buildTheGanttChart',
		'dateTo': 'buildTheGanttChart',
		'listId': 'parseTasks',
	},
	created() {
		this.now = new Date()
		this.taskCollectionService = new TaskCollectionService()
		this.taskService = new TaskService()
		this.priorities = priorities
	},
	mounted() {
		this.buildTheGanttChart()
	},
	computed: mapState({
		canWrite: state => state.currentList.maxRight > Rights.READ,
	}),
	methods: {
		buildTheGanttChart() {
			this.setDates()
			this.prepareGanttDays()
			this.parseTasks()
		},
		setDates() {
			this.startDate = new Date(this.dateFrom)
			this.endDate = new Date(this.dateTo)

			this.dayOffsetUntilToday = Math.floor((this.now - this.startDate) / 1000 / 60 / 60 / 24) + 1
		},
		prepareGanttDays() {
			// Layout: years => [months => [days]]
			let years = {}
			for (let d = this.startDate; d <= this.endDate; d.setDate(d.getDate() + 1)) {
				let date = new Date(d)
				if (years[date.getFullYear() + ''] === undefined) {
					years[date.getFullYear() + ''] = {}
				}
				if (years[date.getFullYear() + ''][date.getMonth() + ''] === undefined) {
					years[date.getFullYear() + ''][date.getMonth() + ''] = []
				}
				years[date.getFullYear() + ''][date.getMonth() + ''].push(date)
				this.fullWidth += this.dayWidth
			}
			this.$set(this, 'days', years)
		},
		parseTasks() {
			this.setDates()
			this.loadTasks()
		},
		loadTasks() {
			this.$set(this, 'theTasks', [])
			this.$set(this, 'tasksWithoutDates', [])

			const getAllTasks = (page = 1) => {
				return this.taskCollectionService.getAll({listId: this.listId}, this.params, page)
					.then(tasks => {
						if (page < this.taskCollectionService.totalPages) {
							return getAllTasks(page + 1)
								.then(nextTasks => {
									return tasks.concat(nextTasks)
								})
						} else {
							return tasks
						}
					})
					.catch(e => {
						return Promise.reject(e)
					})
			}

			getAllTasks()
				.then(tasks => {
					this.theTasks = tasks
						.filter(t => {
							if (t.startDate === null && !t.done) {
								this.tasksWithoutDates.push(t)
							}
							return t.startDate >= this.startDate && t.endDate <= this.endDate
						})
						.map(t => {
							return this.addGantAttributes(t)
						})
						.sort(function (a, b) {
							if (a.startDate < b.startDate)
								return -1
							if (a.startDate > b.startDate)
								return 1
							return 0
						})
				})
				.catch(e => {
					this.error(e, this)
				})
		},
		addGantAttributes(t) {
			t.endDate === null ? this.endDate : t.endDate
			t.durationDays = Math.floor((t.endDate - t.startDate) / 1000 / 60 / 60 / 24) + 1
			t.offsetDays = Math.floor((t.startDate - this.startDate) / 1000 / 60 / 60 / 24) + 1
			return t
		},
		setTaskDragged(t) {
			this.taskDragged = t
		},
		resizeTask(newRect) {

			// Timeout to definitly catch if the user clicked on taskedit
			setTimeout(() => {

				if (this.isTaskEdit) {
					return
				}

				let didntHaveDates = this.taskDragged.startDate === null ? true : false

				let startDate = new Date(this.startDate)
				startDate.setDate(startDate.getDate() + newRect.left / this.dayWidth)
				startDate.setUTCHours(0)
				startDate.setUTCMinutes(0)
				startDate.setUTCSeconds(0)
				startDate.setUTCMilliseconds(0)
				this.taskDragged.startDate = startDate
				let endDate = new Date(startDate)
				endDate.setDate(startDate.getDate() + newRect.width / this.dayWidth)
				this.taskDragged.startDate = startDate
				this.taskDragged.endDate = endDate


				// We take the task from the overall tasks array because the one in it has bad data after it was updated once.
				// FIXME: This is a workaround. We should use a better mechanism to get the task or, even better,
				// prevent it from containing outdated Data in the first place.
				for (const tt in this.theTasks) {
					if (this.theTasks[tt].id === this.taskDragged.id) {
						this.$set(this, 'taskDragged', this.theTasks[tt])
						break
					}
				}

				this.taskService.update(this.taskDragged)
					.then(r => {
						// If the task didn't have dates before, we'll update the list
						if (didntHaveDates) {
							for (const t in this.tasksWithoutDates) {
								if (this.tasksWithoutDates[t].id === r.id) {
									this.tasksWithoutDates.splice(t, 1)
									break
								}
							}
							this.theTasks.push(this.addGantAttributes(r))
						} else {
							for (const tt in this.theTasks) {
								if (this.theTasks[tt].id === r.id) {
									this.$set(this.theTasks, tt, this.addGantAttributes(r))
									break
								}
							}
						}
					})
					.catch(e => {
						this.error(e, this)
					})
			}, 100)
		},
		editTask(task) {
			this.taskToEdit = task
			this.isTaskEdit = true
		},
		showCreateNewTask() {
			if (!this.newTaskFieldActive) {
				// Timeout to not send the form if the field isn't even shown
				setTimeout(() => {
					this.newTaskFieldActive = true
					this.$nextTick(() => this.$refs.newTaskTitleField.focus())
				}, 100)
			}
		},
		hideCrateNewTask() {
			if (this.newTaskTitle === '') {
				this.$nextTick(() => this.newTaskFieldActive = false)
			}
		},
		addNewTask() {
			if (!this.newTaskFieldActive) {
				return
			}
			let task = new TaskModel({title: this.newTaskTitle, listId: this.listId})
			this.taskService.create(task)
				.then(r => {
					this.tasksWithoutDates.push(this.addGantAttributes(r))
					this.newTaskTitle = ''
					this.hideCrateNewTask()
				})
				.catch(e => {
					this.error(e, this)
				})
		},
	},
}
</script>
