package ui

import (
	"cmp"
	"context"
	"fmt"
	"slices"

	"github.com/rivo/tview"

	"git.stinnesbeck.com/nils/arr-tui/internal/arr"
	"git.stinnesbeck.com/nils/arr-tui/internal/sonarr"
)

// seasonSummary counts the episodes of one season.
type seasonSummary struct {
	number, total, have int
}

// summarizeSeasons groups episodes by season, newest season first and specials last.
func summarizeSeasons(episodes []sonarr.Episode) []seasonSummary {
	byNumber := map[int]*seasonSummary{}
	for _, e := range episodes {
		s := byNumber[e.SeasonNumber]
		if s == nil {
			s = &seasonSummary{number: e.SeasonNumber}
			byNumber[e.SeasonNumber] = s
		}
		s.total++
		if e.HasFile {
			s.have++
		}
	}
	out := make([]seasonSummary, 0, len(byNumber))
	for _, s := range byNumber {
		out = append(out, *s)
	}
	slices.SortFunc(out, func(a, b seasonSummary) int {
		// specials (season 0) last, otherwise descending
		return cmp.Or(cmp.Compare(boolInt(a.number == 0), boolInt(b.number == 0)), cmp.Compare(b.number, a.number))
	})
	return out
}

func seasonLabel(n int) string {
	if n == 0 {
		return "Specials"
	}
	return fmt.Sprintf("Season %d", n)
}

// pickList shows a selectable list in a dialog; Esc closes it.
func (a *App) pickList(title string, labels []string, onPick func(i int)) {
	list := tview.NewList().ShowSecondaryText(false)
	for _, l := range labels {
		list.AddItem(l, "", 0, nil)
	}
	list.SetSelectedFunc(func(i int, _, _ string, _ rune) {
		a.closeModal()
		onPick(i)
	})
	list.SetDoneFunc(a.closeModal)
	list.SetBorder(true).SetTitle(" " + title + " ")
	a.openModal(list, 56, min(len(labels)+2, 22))
}

// pickSeason lets the user choose a season, then an episode or the whole season,
// and opens the interactive search for it.
func (a *App) pickSeason(c *sonarr.Client, s sonarr.Series, episodes []sonarr.Episode) {
	seasons := summarizeSeasons(episodes)
	if len(seasons) == 0 {
		a.SetMessage("[yellow]Sonarr has no episodes for " + tview.Escape(s.Title))
		return
	}
	labels := make([]string, len(seasons))
	for i, se := range seasons {
		labels[i] = fmt.Sprintf("%s  (%d/%d downloaded)", seasonLabel(se.number), se.have, se.total)
	}
	a.pickList("Search releases for "+tview.Escape(s.Title), labels, func(i int) {
		a.pickEpisode(c, s, seasons[i].number, episodes)
	})
}

func (a *App) pickEpisode(c *sonarr.Client, s sonarr.Series, season int, all []sonarr.Episode) {
	var episodes []sonarr.Episode
	for _, e := range all {
		if e.SeasonNumber == season {
			episodes = append(episodes, e)
		}
	}
	slices.SortFunc(episodes, func(x, y sonarr.Episode) int { return cmp.Compare(x.EpisodeNumber, y.EpisodeNumber) })

	labels := []string{"Whole season"}
	for _, e := range episodes {
		mark := ""
		if e.HasFile {
			mark = "  ✓"
		}
		labels = append(labels, fmt.Sprintf("E%02d  %s%s", e.EpisodeNumber, tview.Escape(e.Title), mark))
	}
	title := tview.Escape(s.Title) + ", " + seasonLabel(season)
	a.pickList(title, labels, func(i int) {
		if i == 0 {
			a.openReleases("Releases for "+title,
				func(ctx context.Context) ([]arr.Release, error) { return c.SeasonReleases(ctx, s.ID, season) },
				c.Grab)
			return
		}
		e := episodes[i-1]
		a.openReleases(fmt.Sprintf("Releases for %s S%02dE%02d", tview.Escape(s.Title), season, e.EpisodeNumber),
			func(ctx context.Context) ([]arr.Release, error) { return c.EpisodeReleases(ctx, e.ID) },
			c.Grab)
	})
}