package gui

import (
	"fmt"
	"image"
	"log/slog"
	"os"
	"strings"
	"time"

	"github.com/hajimehoshi/ebiten/v2"
	"go.uber.org/fx"
	"tuxpa.in/t/erm/app/darktile/config"
	"tuxpa.in/t/erm/app/darktile/font"
	"tuxpa.in/t/erm/app/darktile/gui/popup"
	"tuxpa.in/t/erm/app/darktile/hinters"
	"tuxpa.in/t/erm/app/darktile/termutil"
	termutil2 "tuxpa.in/t/erm/app/darktile/termutil"
)

type GUI struct {
	mouseStateLeft      MouseState
	mouseStateRight     MouseState
	mouseStateMiddle    MouseState
	mouseDrag           bool
	size                image.Point // pixels
	terminal            *termutil2.Terminal
	updateChan          chan struct{}
	lastClick           time.Time
	clickCount          int
	fontManager         *font.Manager
	mousePos            termutil2.Position
	hinters             []hinters.Hinter
	activeHinter        int
	popupMessages       []popup.Message
	screenshotRequested bool
	screenshotFilename  string
	startupFuncs        []func(g *GUI)
	keyState            *keyState
	opacity             float64
	enableLigatures     bool
	cursorImage         *ebiten.Image

	log   *slog.Logger
	theme *termutil.Theme
	c     *config.Lark
}

type MouseState uint8

const (
	MouseStateNone MouseState = iota
	MouseStatePressed
)

func New(terminal *termutil2.Terminal, c *config.Lark, log *slog.Logger) (*GUI, error) {
	g := &GUI{
		terminal:        terminal,
		size:            image.Point{80, 30},
		updateChan:      make(chan struct{}),
		fontManager:     font.NewManager(),
		activeHinter:    -1,
		keyState:        newKeyState(),
		enableLigatures: true,
		c:               c,
		log:             log,
		theme:           termutil.ThemeFromLark(c),
	}
	terminal.SetWindowManipulator(NewManipulator(g))
	return g, nil
}

func (g *GUI) Run(s fx.Shutdowner) error {
	go func() {
		if err := g.terminal.Run(g.updateChan, uint16(g.size.X), uint16(g.size.Y)); err != nil {
			fmt.Fprintf(os.Stderr, "Fatal error: %s", err)
			s.Shutdown(fx.ExitCode(1))
		}
		s.Shutdown(fx.ExitCode(0))
	}()

	font, err := g.c.Font("font")
	if err != nil {
		return err
	}
	g.log.Info("running gui", "font", font)
	g.fontManager.SetFontByFamilyName(font.Family)
	if font.Size > 0 {
		g.fontManager.SetSize(font.Size)
	}
	if len(font.Style) > 0 {
		g.fontManager.SetFontStyle(font.Style)
	}
	g.fontManager.SetDPI(96)
	g.enableLigatures = font.Ligatures

	ebiten.SetWindowTitle("erm")
	ebiten.SetScreenClearedEveryFrame(true)
	ebiten.SetWindowResizingMode(ebiten.WindowResizingModeEnabled)
	ebiten.SetRunnableOnUnfocused(true)
	ebiten.SetTPS(144)
	ebiten.SetScreenClearedEveryFrame(false)
	if g.c.Truthy("vsync") {
		ebiten.SetVsyncEnabled(true)
	} else {
		ebiten.SetVsyncEnabled(false)
	}

	for _, f := range g.startupFuncs {
		go f(g)
	}

	return ebiten.RunGame(g)
}

func (g *GUI) CellSize() image.Point {
	return g.fontManager.CharSize()
}

func (g *GUI) Highlight(start termutil2.Position, end termutil2.Position, label string, img image.Image) {

	if label == "" && img == nil {
		g.terminal.GetActiveBuffer().Highlight(start, end, nil)
		return
	}

	annotation := &termutil2.Annotation{
		Text:  label,
		Image: img,
	}

	if label != "" {
		lines := strings.Split(label, "\n")
		annotation.Height = float64(len(lines))
		for _, line := range lines {
			if float64(len(line)) > annotation.Width {
				annotation.Width = float64(len(line))
			}
		}
	}

	if img != nil {
		annotation.Height += float64(img.Bounds().Dy() / g.fontManager.CharSize().Y)
		if label != "" {
			annotation.Height += 0.5 // half line spacing between image + text
		}
		imgCellWidth := img.Bounds().Dx() / g.fontManager.CharSize().X
		if float64(imgCellWidth) > annotation.Width {
			annotation.Width = float64(imgCellWidth)
		}
	}

	g.terminal.GetActiveBuffer().Highlight(start, end, annotation)
}

func (g *GUI) ClearHighlight() {
	g.terminal.GetActiveBuffer().ClearHighlight()
}