package ui

import (
	"slices"
	"strings"

	"github.com/rivo/tview"

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

// attrFilter narrows the library by properties of the downloaded files. An
// empty field means "any". All fields must match the same file; a series
// matches when any of its files does.
type attrFilter struct {
	res, codec, hdr, audio, lang string
}

const anyOption = "any"

var (
	resOptions   = []string{"2160p", "1080p", "720p", "SD"}
	codecOptions = []string{arr.CodecX265, arr.CodecX264, arr.CodecAV1}
	hdrOptions   = []string{"HDR", "DV", "SDR"}
	audioOptions = []string{arr.AudioAtmos, arr.AudioTrueHD, arr.AudioDTSX, arr.AudioDTSHD, arr.AudioDTS,
		arr.AudioDDPlus, arr.AudioDD, arr.AudioAAC, arr.AudioFLAC, arr.AudioOpus}
)

func (f attrFilter) active() bool { return f != attrFilter{} }

// String lists the active criteria for the header, e.g. "1080p x265 DV".
func (f attrFilter) String() string {
	var parts []string
	for _, p := range []string{f.res, f.codec, f.hdr, f.audio, f.lang} {
		if p != "" {
			parts = append(parts, p)
		}
	}
	return strings.Join(parts, " ")
}

func (f attrFilter) matchFile(a arr.FileAttrs) bool {
	switch f.res {
	case "":
	case "SD":
		if a.Resolution <= 0 || a.Resolution > 576 {
			return false
		}
	default:
		if f.res != itoa(a.Resolution)+"p" {
			return false
		}
	}
	if f.codec != "" && f.codec != a.Codec {
		return false
	}
	switch f.hdr {
	case "HDR":
		if !a.HDR {
			return false
		}
	case "DV":
		if !a.DV {
			return false
		}
	case "SDR":
		if a.HDR || a.DV {
			return false
		}
	}
	if f.audio != "" && !slices.Contains(a.Audio, f.audio) {
		return false
	}
	if f.lang != "" && !slices.ContainsFunc(a.Languages, func(l string) bool { return strings.EqualFold(l, f.lang) }) {
		return false
	}
	return true
}

// match reports whether any of the files matches. Without files nothing matches.
func (f attrFilter) match(files []arr.FileAttrs) bool {
	return slices.ContainsFunc(files, f.matchFile)
}

// languagesOf collects the languages of all known files, sorted.
func languagesOf(items ...[]libItem) []string {
	seen := map[string]bool{}
	var out []string
	for _, list := range items {
		for _, it := range list {
			for _, a := range it.attrs {
				for _, l := range a.Languages {
					if !seen[l] {
						seen[l] = true
						out = append(out, l)
					}
				}
			}
		}
	}
	slices.Sort(out)
	return out
}

func indexOf(options []string, v string) int {
	if i := slices.Index(options, v); i >= 0 {
		return i + 1 // option 0 is "any"
	}
	return 0
}

// openAttrFilter shows the dialog to pick quality, codec, HDR, audio and
// language. Every change is passed to set immediately so the list behind the
// dialog follows along; Cancel and Esc restore cur.
func (a *App) openAttrFilter(cur attrFilter, languages []string, set func(attrFilter)) {
	if cur.lang != "" && !slices.Contains(languages, cur.lang) {
		languages = append([]string{cur.lang}, languages...)
	}
	withAny := func(o []string) []string { return append([]string{anyOption}, o...) }
	const (
		lRes   = "Quality"
		lCodec = "Codec"
		lHDR   = "HDR"
		lAudio = "Audio"
		lLang  = "Language"
	)
	form := tview.NewForm().
		AddDropDown(lRes, withAny(resOptions), indexOf(resOptions, cur.res), nil).
		AddDropDown(lCodec, withAny(codecOptions), indexOf(codecOptions, cur.codec), nil).
		AddDropDown(lHDR, withAny(hdrOptions), indexOf(hdrOptions, cur.hdr), nil).
		AddDropDown(lAudio, withAny(audioOptions), indexOf(audioOptions, cur.audio), nil).
		AddDropDown(lLang, withAny(languages), indexOf(languages, cur.lang), nil)

	pick := func(label string, options []string) string {
		i := selected(form, label)
		if i <= 0 {
			return ""
		}
		return options[i-1]
	}
	current := func() attrFilter {
		return attrFilter{
			res:   pick(lRes, resOptions),
			codec: pick(lCodec, codecOptions),
			hdr:   pick(lHDR, hdrOptions),
			audio: pick(lAudio, audioOptions),
			lang:  pick(lLang, languages),
		}
	}
	for _, label := range []string{lRes, lCodec, lHDR, lAudio, lLang} {
		form.GetFormItemByLabel(label).(*tview.DropDown).SetSelectedFunc(func(string, int) { set(current()) })
	}

	cancel := func() {
		a.closeModal()
		set(cur)
	}
	form.AddButton("Apply", a.closeModal)
	form.AddButton("Reset", func() {
		a.closeModal()
		set(attrFilter{})
	})
	form.AddButton("Cancel", cancel)
	form.SetCancelFunc(cancel)
	arrowNavigation(form)
	form.SetBorder(true).SetTitle(" Filter by properties ")
	a.openSidePanel(form, 40, 17, "↑↓ move · ←→ change (applies live) · Enter apply · Esc cancel")
}