package main

import (
	"bytes"
	"embed"
	"encoding/json"
	"flag"
	"fmt"
	"image"
	"image/draw"
	"image/png"
	"log"
	"time"

	"github.com/sahilm/fuzzy"
	app "go.hasen.dev/shirei/app"
	. "go.hasen.dev/shirei"
	. "go.hasen.dev/shirei/widgets"
)

//go:embed data/gitmojis.json data/images
var data embed.FS

//go:embed Icon.png
var iconPNG []byte

var preferredTheme = flag.String("theme", "", "Specify the theme to be used. dark/light")
var linger = flag.String("linger", "", "If specified, linger for the given duration (e.g. 10s) before actually closing.")
var x11 = flag.Bool("x11", false, "Force the X11 backend (Linux, XWayland): uses the window manager's decorations instead of shirei's client-side titlebar")

type Gitmoji struct {
	Emoji       string
	Code        string
	Description string
	Name        string
}

type GitmojiData struct {
	Gitmojis []Gitmoji
}

type GitmojiEntry struct {
	Gitmoji
	Icon *image.RGBA
}

var (
	allEntries     []*GitmojiEntry
	allTerms       []string
	currentEntries []*GitmojiEntry
	filter         string
	appliedFilter  string
	selectedId     int
	listKey        = new(int)
	lingerDuration *time.Duration
	shuttingDown   bool
)

// minimum time to keep the process alive after a copy, so the current frame
// can finish and the backend can flush the clipboard request
const minQuitDelay = 100 * time.Millisecond

func main() {
	flag.Parse()

	gitmojiData, err := loadData()
	if err != nil {
		// TODO show dialog
		panic(err)
	}

	loadEntries(gitmojiData)
	currentEntries = allEntries

	switch *preferredTheme {
	case "dark":
		SetDarkMode(true)
	case "light":
		SetDarkMode(false)
	}

	if *linger != "" {
		if d, err := time.ParseDuration(*linger); err != nil {
			log.Fatalf("invalid linger time: %v\n", err)
		} else {
			lingerDuration = &d
		}
	}

	setupWindow("Gitmoji Picker", 300, 300)
	runWindow(RootView)
}

func loadEntries(gitmojiData *GitmojiData) {
	allEntries = make([]*GitmojiEntry, len(gitmojiData.Gitmojis))
	allTerms = make([]string, len(gitmojiData.Gitmojis))

	for i, gitmoji := range gitmojiData.Gitmojis {
		b, err := data.ReadFile("data/images/" + gitmoji.Name + ".png")
		if err != nil {
			panic(err)
		}
		allEntries[i] = &GitmojiEntry{
			Gitmoji: gitmoji,
			Icon:    decodePNG(b),
		}
		allTerms[i] = gitmoji.Name + " " + gitmoji.Description
	}
}

func decodePNG(b []byte) *image.RGBA {
	img, err := png.Decode(bytes.NewReader(b))
	if err != nil {
		panic(err)
	}
	if rgba, ok := img.(*image.RGBA); ok {
		return rgba
	}
	rgba := image.NewRGBA(img.Bounds())
	draw.Draw(rgba, rgba.Bounds(), img, img.Bounds().Min, draw.Src)
	return rgba
}

func RootView() {
	handleKeys()
	applyFilterChange()

	scheme := CurrentColorScheme
	Container(Attrs(Viewport, BackgroundVec(scheme.Surfaces.Canvas.Background)), func() {
		attrs := DefaultTextInputAttrs()
		attrs.NoUpDownLineEdges = true // leave Up/Down for list navigation
		TextInputExt(&filter, attrs)

		VirtualListView(listKey, len(currentEntries),
			func(i int) any { return i },
			nil, // auto-height via Measure
			rowView,
		)
	})
}

func applyFilterChange() {
	if filter == appliedFilter {
		return
	}
	appliedFilter = filter

	if filter == "" {
		currentEntries = allEntries
	} else {
		r := fuzzy.Find(filter, allTerms)
		currentEntries = make([]*GitmojiEntry, len(r))
		for i := range r {
			currentEntries[i] = allEntries[r[i].Index]
		}
	}

	if len(currentEntries) > 0 {
		selectedId = 0
		VirtualListScrollIntoView(listKey, selectedId)
	} else {
		selectedId = -1
	}
}

func handleKeys() {
	if shuttingDown {
		return
	}

	switch GetFrameInput().Key {
	case KeyDown:
		if selectedId < len(currentEntries)-1 {
			selectEntry(selectedId + 1)
		}
	case KeyUp:
		if selectedId > 0 {
			selectEntry(selectedId - 1)
		}
	case KeyEscape:
		app.Quit()
	case KeyEnter:
		if selectedId > -1 {
			pickGitmoji()
		}
	}
}

func selectEntry(idx int) {
	selectedId = idx
	VirtualListScrollIntoView(listKey, idx)
}

func rowView(idx int, width float32) {
	entry := currentEntries[idx]
	icon := UseImage("gitmoji:"+entry.Name, entry.Icon)

	scheme := CurrentColorScheme
	nameColor := scheme.Surfaces.Canvas.Text
	descColor := nameColor
	descColor[3] = 0.65
	hoverColor := nameColor
	hoverColor[3] = 0.08
	selectedColor := scheme.Buttons.Primary.Normal.Background
	selectedColor[3] = 0.35

	Container(Attrs(Row, CrossMid, Gap(8), Pad2(5, 10), Expand, Clip), func() {
		if idx == selectedId {
			ModAttrs(BackgroundVec(selectedColor))
		} else if IsHovered() {
			ModAttrs(BackgroundVec(hoverColor))
		}
		if IsClicked() {
			selectEntry(idx)
		}

		ImageView(icon, Vec2{20, 20})
		Container(Attrs(Expand), func() {
			Label(entry.Name, FontWeight(WeightBold), TextColorVec(nameColor))
			Label(entry.Description, FontSize(DefaultTextSize*8/10), TextColorVec(descColor))
		})
	})
}

func pickGitmoji() {
	if shuttingDown {
		return
	}
	shuttingDown = true

	RequestTextCopy(currentEntries[selectedId].Emoji)

	delay := minQuitDelay
	if lingerDuration != nil {
		delay = *lingerDuration
	}
	go func() {
		time.Sleep(delay)
		app.Quit()
	}()
}

func loadData() (*GitmojiData, error) {
	b, err := data.ReadFile("data/gitmojis.json")
	if err != nil {
		return nil, fmt.Errorf("cannot read gitmoji data: %w", err)
	}

	var result GitmojiData
	if err := json.Unmarshal(b, &result); err != nil {
		return nil, fmt.Errorf("cannot decode gitmoji data: %w", err)
	}

	return &result, nil
}