package game

import (
	"fmt"
	"image/color"
	"sort"
	"strings"

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

	"gitea.brasse-pc.eu/brasse/metro-puzzle-jp/internal/progress"
)

// SkillsScene är skillträdet: grenar med noder, kostnad i skillpoäng och krav.
type SkillsScene struct {
	back   Scene
	skills []progress.Skill
	sel    int
	top    int
	msg    string
}

const skillRows = 8

// NewSkillsScene listar skills gren för gren.
func NewSkillsScene(g *Game, back Scene) *SkillsScene {
	sk := append([]progress.Skill(nil), g.Catalog.Skills...)
	sort.SliceStable(sk, func(i, j int) bool {
		if sk[i].Branch != sk[j].Branch {
			return sk[i].Branch < sk[j].Branch
		}
		return len(sk[i].Requires) < len(sk[j].Requires)
	})
	return &SkillsScene{back: back, skills: sk}
}

func (s *SkillsScene) Update(g *Game) error {
	if backJustPressed() || skillsJustPressed() {
		g.SetScene(s.back)
		return nil
	}
	if n := len(s.skills); n > 0 {
		s.sel = (s.sel + menuMove() + n) % n
		if s.sel < s.top {
			s.top = s.sel
		}
		if s.sel >= s.top+skillRows {
			s.top = s.sel - skillRows + 1
		}
		if confirmJustPressed() {
			sk := s.skills[s.sel]
			switch {
			case g.Progress.Has(sk.ID):
				s.msg = g.Assets.T("skills.already")
			case g.Progress.Unlock(g.Catalog, sk.ID):
				s.msg = fmt.Sprintf(g.Assets.T("skills.unlocked"), sk.Name.Get(UILang))
				g.Save()
			case g.Progress.SkillPoints < sk.Cost:
				s.msg = fmt.Sprintf(g.Assets.T("skills.need_points"), sk.Cost)
			default:
				s.msg = g.Assets.T("skills.need_req")
			}
		}
	}
	return nil
}

func (s *SkillsScene) Draw(g *Game, screen *ebiten.Image) {
	a := g.Assets
	p := g.Progress
	screen.Fill(color.RGBA{24, 20, 37, 255})
	vector.DrawFilledRect(screen, 0, 0, ScreenW, 22, color.RGBA{38, 43, 68, 255}, false)
	a.DrawBig(screen, a.T("skills.title"), 8, 5, colText)
	hdr := fmt.Sprintf("%s %d   %s %d  %s %d", a.T("map.skill_points"), p.SkillPoints, a.T("map.level"), p.Level(), a.T("skills.to_next"), progress_XPToNext(p.XP))
	a.Draw(screen, hdr, ScreenW-8-a.Width(hdr), 6, colKnown)

	y0 := 30
	for i := s.top; i < len(s.skills) && i < s.top+skillRows; i++ {
		sk := s.skills[i]
		y := y0 + (i-s.top)*LineH
		if i == s.sel {
			vector.DrawFilledRect(screen, 4, float32(y-1), ScreenW-8, LineH, colBar, false)
		}
		col, status := colDim, strings.Repeat("●", sk.Cost)
		switch {
		case p.Has(sk.ID):
			col, status = colGood, "✓"
		case p.CanUnlock(g.Catalog, sk.ID):
			col = colKnown
		}
		a.Draw(screen, sk.Branch, 8, y, colDim)
		a.Draw(screen, sk.Name.Get(UILang), 80, y, col)
		if len(sk.Requires) > 0 {
			req := make([]string, len(sk.Requires))
			for k, r := range sk.Requires {
				req[k] = g.Catalog.Skill(r).Name.Get(UILang)
			}
			a.Draw(screen, "← "+strings.Join(req, ", "), 190, y, colDim)
		}
		a.Draw(screen, status, ScreenW-8-a.Width(status), y, col)
	}
	if len(s.skills) > 0 {
		sel := s.skills[s.sel]
		for i, l := range a.wrapLine(plainLine(sel.Desc.Get(UILang), colText), ScreenW-16) {
			a.drawLines(screen, []line{l}, 8, 130+i*LineH)
		}
	}
	if s.msg != "" {
		a.Draw(screen, s.msg, 8, ScreenH-26, colKnown)
	}
	a.Draw(screen, a.T("skills.hint"), 8, ScreenH-13, colDim)
}