package templates

import "fmt"

// CalendarSummary is one of the user's own calendars, listed on the
// calendar home page.
type CalendarSummary struct {
	Name  string
	Color string // hex color like "#3b82f6", "" if unset
}

// EventSummary is a single event shown inside a month-view day cell.
type EventSummary struct {
	ID       string
	Summary  string
	TimeText string // e.g. "14:00" or "" for all-day events
	AllDay   bool
}

// MonthDay is one day cell in the month grid.
type MonthDay struct {
	Date     string // "YYYY-MM-DD", used for links and the "new event" date
	Day      int    // day-of-month number shown in the cell
	InMonth  bool   // false for the leading/trailing days of neighboring months
	IsToday  bool
	Events   []EventSummary
}

// MonthViewData is everything the month grid template needs to render one
// month of a single calendar.
type MonthViewData struct {
	Cal          string
	Color        string
	MonthLabel   string // e.g. "August 2026"
	Weeks        [][]MonthDay
	PrevMonthURL string
	NextMonthURL string
	TodayURL     string
}

// EventFormData pre-fills the create/edit event form.
type EventFormData struct {
	Cal         string
	ID          string // empty when creating a new event
	Summary     string
	Description string
	Location    string
	AllDay      bool
	StartDate   string // "YYYY-MM-DD"
	StartTime   string // "HH:MM", empty when AllDay
	EndDate     string // "YYYY-MM-DD"
	EndTime     string // "HH:MM", empty when AllDay
}

templ CalendarsHome(username string, calendars []CalendarSummary) {
	@Layout("Calendar", username) {
		<h1 class="text-2xl font-semibold mb-6">Calendar</h1>
		if len(calendars) == 0 {
			<p class="text-sm text-gray-500">
				You don't have any calendars yet — create one from the
				<a href="/web/" class="text-indigo-600 hover:underline">dashboard</a> first.
			</p>
		} else {
			<ul class="divide-y divide-gray-200 bg-white rounded-lg border border-gray-200">
				for _, c := range calendars {
					<li class="px-4 py-3 flex items-center gap-3 text-sm">
						<span class="w-3 h-3 rounded-full shrink-0" style={ "background-color: " + colorOrDefault(c.Color) }></span>
						<a href={ templ.URL("/web/calendar/" + c.Name) } class="font-medium text-indigo-600 hover:underline">{ c.Name }</a>
					</li>
				}
			</ul>
		}
	}
}

templ MonthView(username string, data MonthViewData) {
	@Layout("Calendar", username) {
		<div class="flex items-center justify-between mb-6 gap-4 flex-wrap">
			<div>
				<a href="/web/calendar" class="text-sm text-indigo-600 hover:underline">&larr; Calendars</a>
				<h1 class="text-2xl font-semibold flex items-center gap-2">
					<span class="w-3 h-3 rounded-full shrink-0" style={ "background-color: " + colorOrDefault(data.Color) }></span>
					{ data.Cal }
				</h1>
			</div>
			<div class="flex gap-2 items-center flex-wrap">
				<a href={ templ.URL(data.PrevMonthURL) } class="bg-white border border-gray-300 rounded-md px-3 py-1.5 text-sm font-medium text-gray-700 hover:bg-gray-50">&larr;</a>
				<a href={ templ.URL(data.TodayURL) } class="bg-white border border-gray-300 rounded-md px-3 py-1.5 text-sm font-medium text-gray-700 hover:bg-gray-50">Today</a>
				<a href={ templ.URL(data.NextMonthURL) } class="bg-white border border-gray-300 rounded-md px-3 py-1.5 text-sm font-medium text-gray-700 hover:bg-gray-50">&rarr;</a>
				<span class="text-lg font-medium ml-2">{ data.MonthLabel }</span>
				<a href={ templ.URL("/web/calendar/" + data.Cal + "/new") }
					class="bg-indigo-600 text-white rounded-md px-3 py-1.5 text-sm font-medium hover:bg-indigo-700 ml-2">
					New event
				</a>
			</div>
		</div>

		<div class="grid grid-cols-7 gap-px bg-gray-200 border border-gray-200 rounded-lg overflow-hidden text-sm">
			for _, wd := range weekdayLabels() {
				<div class="bg-gray-50 px-2 py-1.5 font-medium text-gray-500 text-xs text-center">{ wd }</div>
			}
			for _, week := range data.Weeks {
				for _, day := range week {
					@monthDayCell(data.Cal, day)
				}
			}
		</div>
	}
}

templ monthDayCell(cal string, day MonthDay) {
	<div class={ "bg-white min-h-[6rem] p-1.5 flex flex-col gap-1", templ.KV("bg-gray-50 text-gray-400", !day.InMonth) }>
		<div class="flex items-center justify-between">
			<a
				href={ templ.URL("/web/calendar/" + cal + "/new?date=" + day.Date) }
				class={ "text-xs font-medium rounded-full w-5 h-5 flex items-center justify-center", templ.KV("bg-indigo-600 text-white", day.IsToday), templ.KV("hover:bg-gray-100", !day.IsToday) }
				title="New event"
			>
				{ fmt.Sprint(day.Day) }
			</a>
		</div>
		for _, ev := range day.Events {
			<a
				href={ templ.URL("/web/calendar/" + cal + "/" + ev.ID + "/edit") }
				class="block truncate rounded bg-indigo-50 text-indigo-700 px-1.5 py-0.5 text-xs hover:bg-indigo-100"
				title={ ev.Summary }
			>
				if !ev.AllDay && ev.TimeText != "" {
					<span class="font-medium">{ ev.TimeText }</span>
				}
				{ " " + ev.Summary }
			</a>
		}
	</div>
}

templ EventForm(username string, data EventFormData, errMsg string) {
	@Layout("Calendar", username) {
		<a href={ templ.URL("/web/calendar/" + data.Cal) } class="text-sm text-indigo-600 hover:underline">&larr; { data.Cal }</a>
		<h1 class="text-2xl font-semibold mt-2 mb-6">
			if data.ID == "" {
				New event
			} else {
				Edit event
			}
		</h1>
		if errMsg != "" {
			<p class="mb-4 text-sm text-red-600 bg-red-50 border border-red-200 rounded px-3 py-2">{ errMsg }</p>
		}
		<form
			method="POST"
			action={ eventFormAction(data) }
			class="bg-white rounded-lg border border-gray-200 p-6 space-y-6 max-w-xl"
		>
			<div>
				<label class="block text-sm font-medium text-gray-700">Title</label>
				<input name="summary" type="text" required value={ data.Summary }
					class="mt-1 block w-full rounded-md border-gray-300 border px-3 py-2 shadow-sm"/>
			</div>

			<label class="flex items-center gap-2 text-sm text-gray-700">
				<input id="all-day" name="all_day" type="checkbox" value="1" checked?={ data.AllDay }/>
				All-day event
			</label>

			<div class="grid grid-cols-2 gap-4">
				<div>
					<label class="block text-sm font-medium text-gray-700">Start date</label>
					<input name="start_date" type="date" required value={ data.StartDate }
						class="mt-1 block w-full rounded-md border-gray-300 border px-3 py-2 shadow-sm"/>
				</div>
				<div id="start-time-field" class={ templ.KV("hidden", data.AllDay) }>
					<label class="block text-sm font-medium text-gray-700">Start time</label>
					<input name="start_time" type="time" value={ data.StartTime }
						class="mt-1 block w-full rounded-md border-gray-300 border px-3 py-2 shadow-sm"/>
				</div>
				<div>
					<label class="block text-sm font-medium text-gray-700">End date</label>
					<input name="end_date" type="date" required value={ data.EndDate }
						class="mt-1 block w-full rounded-md border-gray-300 border px-3 py-2 shadow-sm"/>
				</div>
				<div id="end-time-field" class={ templ.KV("hidden", data.AllDay) }>
					<label class="block text-sm font-medium text-gray-700">End time</label>
					<input name="end_time" type="time" value={ data.EndTime }
						class="mt-1 block w-full rounded-md border-gray-300 border px-3 py-2 shadow-sm"/>
				</div>
			</div>

			<div>
				<label class="block text-sm font-medium text-gray-700">Location</label>
				<input name="location" type="text" value={ data.Location }
					class="mt-1 block w-full rounded-md border-gray-300 border px-3 py-2 shadow-sm"/>
			</div>
			<div>
				<label class="block text-sm font-medium text-gray-700">Description</label>
				<textarea name="description" rows="4"
					class="mt-1 block w-full rounded-md border-gray-300 border px-3 py-2 shadow-sm">{ data.Description }</textarea>
			</div>

			<div class="flex items-center justify-between pt-2">
				<button type="submit" class="bg-indigo-600 text-white rounded-md px-4 py-2 text-sm font-medium hover:bg-indigo-700">
					Save
				</button>
				if data.ID != "" {
					<form method="POST" action={ templ.URL("/web/calendar/" + data.Cal + "/" + data.ID + "/delete") } onsubmit="return confirm('Delete this event?')">
						<button type="submit" class="text-red-600 hover:underline text-sm">Delete event</button>
					</form>
				}
			</div>
		</form>

		<script type="module" src="/web/static/calendar.js"></script>
	}
}

func eventFormAction(data EventFormData) templ.SafeURL {
	if data.ID == "" {
		return templ.URL("/web/calendar/" + data.Cal + "/new")
	}
	return templ.URL("/web/calendar/" + data.Cal + "/" + data.ID + "/edit")
}

func weekdayLabels() []string {
	return []string{"Mon", "Tue", "Wed", "Thu", "Fri", "Sat", "Sun"}
}