package game

import (
	"fmt"
	"image"
	"image/color"
	"math"
	"path/filepath"
	"strings"

	"github.com/hajimehoshi/ebiten/v2"
	"github.com/hajimehoshi/ebiten/v2/vector"

	"gitea.brasse-pc.eu/brasse/metro-puzzle-jp/internal/lang"
	"gitea.brasse-pc.eu/brasse/metro-puzzle-jp/internal/level"
	"gitea.brasse-pc.eu/brasse/metro-puzzle-jp/internal/rng"
	"gitea.brasse-pc.eu/brasse/metro-puzzle-jp/internal/sim"
)

// Hur länge tillfälliga meddelanden visas.
const (
	deniedShowSec     = 2.0
	learnedShowSec    = 3.0
	progressedShowSec = 2.5
)

// LevelScene är själva spelandet av en bana. All spellogik ligger i sim.Run;
// scenen översätter input och ritar.
type LevelScene struct {
	id      string
	run     *sim.Run
	cam     *sim.Camera
	animT   float64
	hideMap bool // M döljer/visar minikartan
}

// NewLevelScene laddar banan och ställer spelaren på startrutan. know är
// spelarens japanska, som delas mellan banor; seed styr omgångens slump.
func NewLevelScene(a *Assets, id string, know *lang.Knowledge, seed rng.Seed) (*LevelScene, error) {
	lvl, err := level.LoadFile(filepath.Join(a.LevelsDir, id+".json"))
	if err != nil {
		return nil, err
	}
	s := &LevelScene{
		id:  id,
		run: sim.NewRun(lvl, sim.RunOptions{Dict: a.Dict, Know: know, Seed: seed}),
		cam: sim.NewCamera(ScreenW, ScreenH, float64(lvl.Width()*TileSize), float64(lvl.Height()*TileSize)),
	}
	s.followPlayer()
	return s, nil
}

// PlayerTile returnerar rutan spelaren står på/lämnar (används av skriptläget).
func (s *LevelScene) PlayerTile() level.Point { return s.run.Player.Tile }

// PlayerMoving rapporterar om spelaren är mellan två rutor (skriptläget).
func (s *LevelScene) PlayerMoving() bool { return s.run.Player.Moving() }

// TrainHere rapporterar om spelaren står på en perrong vars tåg är inne (skriptläget).
func (s *LevelScene) TrainHere() bool {
	tr, at, _ := s.run.PlatformHere()
	return tr != nil && at
}

func (s *LevelScene) followPlayer() {
	x, y := s.run.Player.WorldPos(TileSize)
	s.cam.Follow(x+TileSize/2, y+TileSize/2)
}

func (s *LevelScene) Update(g *Game) error {
	if backJustPressed() {
		m, err := NewMenuScene(g.Assets)
		if err != nil {
			return err
		}
		g.SetScene(m)
		return nil
	}
	if helpJustPressed() {
		s.run.AskHelp()
	}
	if mapJustPressed() {
		s.hideMap = !s.hideMap
	}
	s.run.Step(dt, dirInput(), confirmJustPressed())
	if s.run.Player.Moving() {
		s.animT += dt
	} else {
		s.animT = 0
	}
	s.followPlayer()
	if s.run.Outcome != sim.Ongoing {
		g.SetScene(NewResultScene(s))
	}
	return nil
}

// trainTile är rutan "bortom perrongkanten" där tågvagnen ritas: första
// väggruta nedanför, till höger, till vänster eller ovanför perrongen.
func (s *LevelScene) trainTile(p level.Point) level.Point {
	for _, d := range [...]level.Point{{X: 0, Y: 1}, {X: 1, Y: 0}, {X: -1, Y: 0}, {X: 0, Y: -1}} {
		n := level.Point{X: p.X + d.X, Y: p.Y + d.Y}
		if s.run.Level.At(n.X, n.Y) == level.Wall {
			return n
		}
	}
	return p
}

func (s *LevelScene) Draw(g *Game, screen *ebiten.Image) {
	screen.Fill(color.RGBA{24, 20, 37, 255})
	lvl := s.run.Level
	ox, oy := s.cam.Offset()
	ox, oy = math.Round(ox), math.Round(oy)

	// Rita bara rutor som syns.
	x0 := max(0, int(s.cam.X)/TileSize)
	y0 := max(0, int(s.cam.Y)/TileSize)
	x1 := min(lvl.Width(), int(s.cam.X+ScreenW)/TileSize+2)
	y1 := min(lvl.Height(), int(s.cam.Y+ScreenH)/TileSize+2)
	var op ebiten.DrawImageOptions
	for y := y0; y < y1; y++ {
		for x := x0; x < x1; x++ {
			op.GeoM.Reset()
			op.GeoM.Translate(ox+float64(x*TileSize), oy+float64(y*TileSize))
			screen.DrawImage(g.Assets.Tiles[lvl.At(x, y)], &op)
		}
	}
	// Tåg som står inne.
	for _, t := range []level.Tile{level.Platform, level.WrongPlatform} {
		if !s.run.TrainVisible(t) {
			continue
		}
		for _, p := range lvl.Find(t) {
			tt := s.trainTile(p)
			op.GeoM.Reset()
			op.GeoM.Translate(ox+float64(tt.X*TileSize), oy+float64(tt.Y*TileSize))
			screen.DrawImage(g.Assets.Train, &op)
		}
	}

	// Följarna ritas bakifrån så att ledaren hamnar överst.
	leader := s.run.Player
	followers := s.run.Party.Followers()
	for i := len(followers); i >= 1; i-- {
		from, to := s.run.Party.FollowerTiles(i)
		fx := float64(from.X*TileSize) + float64((to.X-from.X)*TileSize)*leader.Progress
		fy := float64(from.Y*TileSize) + float64((to.Y-from.Y)*TileSize)*leader.Progress
		facing := sim.Down
		switch {
		case to.X > from.X:
			facing = sim.Right
		case to.X < from.X:
			facing = sim.Left
		case to.Y < from.Y:
			facing = sim.Up
		}
		op.GeoM.Reset()
		op.GeoM.Translate(ox+math.Round(fx), oy+math.Round(fy))
		op.ColorScale.Reset()
		t := memberTints[i%len(memberTints)]
		op.ColorScale.Scale(t[0], t[1], t[2], 1)
		screen.DrawImage(g.Assets.PlayerFrame(facing, leader.Moving() && from != to, s.animT), &op)
		op.ColorScale.Reset()
		s.drawUrge(g, screen, followers[i-1], int(ox+math.Round(fx)), int(oy+math.Round(fy)))
	}

	px, py := leader.WorldPos(TileSize)
	op.GeoM.Reset()
	op.GeoM.Translate(ox+math.Round(px), oy+math.Round(py))
	screen.DrawImage(g.Assets.PlayerFrame(leader.Facing, leader.Moving(), s.animT), &op)
	s.drawUrge(g, screen, s.run.Party.Members[0], int(ox+math.Round(px)), int(oy+math.Round(py)))

	s.drawHUD(g, screen)
}

// memberTints färgar följarnas sprites tills de har egna.
var memberTints = [][3]float32{{1, 1, 1}, {1, 0.75, 0.55}, {0.7, 0.95, 0.75}, {0.8, 0.7, 1}, {1, 0.95, 0.55}}

// urgeMark är tecknet som visas över huvudet på någon med ett behov.
func urgeMark(u sim.Urge) (string, color.Color) {
	switch u {
	case sim.NeedToilet:
		return "WC", colBad
	case sim.Thirsty:
		return "飲", colEnglish
	case sim.Hungry:
		return "食", colWarn
	case sim.Distracted:
		return "?", colDim
	}
	return "", nil
}

func (s *LevelScene) drawUrge(g *Game, screen *ebiten.Image, m *sim.Member, x, y int) {
	mark, col := urgeMark(m.Urge)
	if mark == "" {
		if m.Meters.Min() <= 0 {
			mark, col = "!!", colBad
		} else {
			return
		}
	}
	w := g.Assets.Width(mark)
	vector.DrawFilledRect(screen, float32(x+8-w/2-1), float32(y-11), float32(w+2), 11, colPanel, false)
	g.Assets.Draw(screen, mark, x+8-w/2, y-12, col)
}

// drawHUD ritar den övre raden (bana, resmål, tid, kort, japanska-nivå) och
// inforutan (perrong, skylt, nekad spärr, nytt ord).
func (s *LevelScene) drawHUD(g *Game, screen *ebiten.Image) {
	r := s.run
	a := g.Assets
	vector.DrawFilledRect(screen, 0, 0, ScreenW, 24, color.RGBA{24, 20, 37, 200}, false)

	dest := r.Level.Destination.Get("romaji")
	if r.Know.ShowsDestinationJP() { // hint från nivå 1: resmålet på japanska, att matcha mot skyltarna
		dest += "  " + r.Level.Destination.Get("ja")
	}
	a.Draw(screen, r.Level.Name.Get(UILang), 4, 0, colText)
	a.Draw(screen, a.T("hud.destination")+": "+dest, 4+a.Width(r.Level.Name.Get(UILang))+12, 0, colKnown)
	a.Draw(screen, fmt.Sprintf("%s %3.0fs  %s %d  %s %d¥  %s Lv%d·%d", a.T("hud.time"), r.Time,
		a.T("hud.steps"), r.Steps, a.T("hud.card"), r.Card.Balance, a.T("hud.japanese"), r.Know.Level(), r.Know.Count()), 4, LineH, colDim)
	s.drawMeters(g, screen)

	if r.Outcome != sim.Ongoing {
		return // resultatpanelen tar över; ingen inforuta eller minikarta
	}
	lines, accent, bar := s.infoLines(a)
	if entry := a.Dict.Lookup(r.Learned); entry != nil && r.Time-r.LearnedAt < learnedShowSec {
		lines = append(lines, plainLine(fmt.Sprintf("%s: %s = %s (%s)", a.T("hud.learned"), r.Learned,
			entry.Translation(UILang), entry.Romaji), colKnown))
	}
	if len(r.Progressed) > 0 && r.Time-r.ProgressedAt < progressedShowSec {
		lines = append(lines, a.wrapLine(plainLine(a.T("hud.progress")+": "+strings.Join(r.Progressed, ", "), colWarn), ScreenW-8)...)
	}
	if urges := r.Party.Urges(); len(urges) > 0 {
		var parts []string
		for _, m := range urges {
			parts = append(parts, m.Name+": "+a.T("urge."+m.Urge.String()))
		}
		lines = append(lines, a.wrapLine(plainLine(strings.Join(parts, "   "), colWarn), ScreenW-8)...)
	}

	// Inforutans läge: nederkant, men flyttas upp under HUD:en om spelaren
	// (eller tåget under hen) annars skulle hamna bakom den.
	var box image.Rectangle
	hasBox := len(lines) > 0
	if hasBox {
		h := 8 + LineH*len(lines)
		if bar {
			h += 8
		}
		_, py := r.Player.WorldPos(TileSize)
		y := ScreenH - h
		if int(py-s.cam.Y)+2*TileSize > y {
			y = 24
		}
		box = image.Rect(0, y, ScreenW, y+h)
	}
	if !s.hideMap {
		s.drawMinimap(g, screen, box, hasBox)
	}
	if !hasBox {
		return
	}
	y, h := box.Min.Y, box.Dy()
	vector.DrawFilledRect(screen, 0, float32(y), ScreenW, float32(h), colPanel, false)
	vector.DrawFilledRect(screen, 0, float32(y), ScreenW, 2, accent, false)
	a.drawLines(screen, lines, 4, y+4)
	if bar {
		p := r.HelpProgress()
		if r.Facility.Active {
			p = r.FacilityProgress()
		}
		by := float32(y + h - 7)
		vector.DrawFilledRect(screen, 4, by, ScreenW-8, 4, colBar, false)
		vector.DrawFilledRect(screen, 4, by, float32((ScreenW-8)*p), 4, colKnown, false)
	}
}

// infoLines bygger inforutans rader: perronginfo, skylt eller nekad spärr.
func (s *LevelScene) infoLines(a *Assets) (lines []line, accent color.Color, bar bool) {
	r := s.run
	lvl := r.Level
	tile := r.Player.Tile
	accent = colBar
	maxW := ScreenW - 8
	english := lang.ShowEnglish(lvl.ID, tile.X, tile.Y, lvl.Difficulty)

	if tr, at, secs := r.PlatformHere(); tr != nil {
		// Avgångstavlan är en skylt som alla andra: japanska, sedd genom kunskapen.
		rd := lang.Render(a.Dict, r.Know, tr.BoardText(), UILang)
		lines = append(lines, a.wrapLine(shownLine(rd.Original, colText, r.Know.ShowsReadings()), maxW)...)
		lines = append(lines, a.wrapLine(shownLine(rd.Partial, colText, false), maxW)...)
		if english {
			lines = append(lines, a.wrapLine(plainLine(fmt.Sprintf("%s: Track %s  %s for %s", a.T("hud.english"), tr.Track,
				tr.Line.Get("en"), tr.Destination.Get("en")), colEnglish), maxW)...)
		}
		if at {
			accent = colGood
			lines = append(lines, plainLine(fmt.Sprintf("%s %.0f s     %s", a.T("hud.departs_in"), math.Ceil(secs), a.T("hud.board")), colGood))
		} else {
			accent = colWarn
			lines = append(lines, plainLine(fmt.Sprintf("%s %.0f s", a.T("hud.next_train_in"), math.Ceil(secs)), colWarn))
		}
		return lines, accent, false
	}

	if sg := r.SignHere(); sg != nil {
		know := r.Know
		revealed := r.SignRevealed(tile)
		if revealed {
			know = nil // allt känt
			accent = colKnown
		}
		rd := lang.Render(a.Dict, know, sg.Text["ja"], UILang)
		lines = append(lines, a.wrapLine(shownLine(rd.Original, colText, r.Know.ShowsReadings()), maxW)...)
		lines = append(lines, a.wrapLine(shownLine(rd.Partial, colText, false), maxW)...)
		if english {
			lines = append(lines, a.wrapLine(plainLine(a.T("hud.english")+": "+sg.Text.Get("en"), colEnglish), maxW)...)
		}
		switch {
		case r.Help.Active:
			lines = append(lines, plainLine(a.T("hud.help_progress"), colDim))
			bar = true
		case !revealed:
			lines = append(lines, plainLine(fmt.Sprintf(a.T("hud.help_prompt"), lang.HelpSeconds(r.Know.Level())), colDim))
		}
		return lines, accent, bar
	}

	switch lvl.At(tile.X, tile.Y) {
	case level.Toilet:
		if r.Facility.Active {
			return []line{plainLine(a.T("hud.toilet_busy"), colDim)}, colGood, true
		}
		if n := len(r.Party.NeedsToilet()); n > 0 {
			return []line{plainLine(fmt.Sprintf(a.T("hud.toilet_prompt"), n, sim.ToiletSecPerMember*float64(n)), colGood)}, colGood, false
		}
		return []line{plainLine(a.T("hud.toilet_none"), colDim)}, accent, false
	case level.Kiosk:
		if n := len(r.Party.NeedsKiosk()); n > 0 {
			return []line{plainLine(fmt.Sprintf(a.T("hud.kiosk_prompt"), n, sim.KioskPriceYen*n), colGood)}, colGood, false
		}
		return []line{plainLine(a.T("hud.kiosk_none"), colDim)}, accent, false
	}
	if r.DeniedAt >= 0 && r.Time-r.DeniedAt < deniedShowSec {
		return []line{plainLine(a.T("hud.gate_denied"), colBad)}, colBad, false
	}
	return nil, accent, false
}

// drawMeters ritar sällskapets mat/dryck/toa-mätare uppe till höger.
func (s *LevelScene) drawMeters(g *Game, screen *ebiten.Image) {
	members := s.run.Party.Members
	const w, gap = 14, 4
	x0 := ScreenW - 4 - len(members)*(w+gap)
	for i, m := range members {
		x := float32(x0 + i*(w+gap))
		g.Assets.Draw(screen, string([]rune(m.Name)[:1]), int(x)+3, 0, colDim)
		for j, v := range []struct {
			val float64
			col color.Color
		}{{m.Meters.Food, colWarn}, {m.Meters.Drink, colEnglish}, {m.Meters.Toilet, colGood}} {
			y := float32(13 + j*3)
			vector.DrawFilledRect(screen, x, y, w, 2, colBar, false)
			c := v.col
			if v.val < sim.UrgeThreshold {
				c = colBad
			}
			vector.DrawFilledRect(screen, x, y, float32(w*v.val/100), 2, c, false)
		}
	}
}