package main

import (
	"fmt"
	"io"
	"log"
	"os"
	"slices"
	"strings"

	_ "embed"

	rg "github.com/gen2brain/raylib-go/raygui"
	rl "github.com/gen2brain/raylib-go/raylib"
	"github.com/ktr0731/go-fuzzyfinder/matching"
)

const windowWidth = 800
const fontSize = 20
const textBoxHeight = fontSize + 6

// TODO: move the raymenu function to its own package

//go:embed gomono-font/Go-Mono.ttf
var font_tff []byte

type State struct {
    Font rl.Font
}

func main() {
    input, err := io.ReadAll(os.Stdin)
    if err != nil {
        log.Fatalln(err)
    }
    lines := strings.Split(string(input), "\n")
    lines = slices.DeleteFunc(lines, func(l string) bool {
        return l == ""
    })
    choice, result := raymenu(lines)
    switch (result) {
        case RayMenuResult_NoChoice:
            return
        case RayMenuResult_Chosen:
            fmt.Println(choice)
            return
        default:
            log.Fatalln("Unhandled RayMenuResult", result)
    }
}

type RayMenuResult int

const (
    RayMenuResult_NoChoice RayMenuResult = iota
    RayMenuResult_Chosen
    Count_RayMenuResult int = iota
)


func isPressedRepeat(key int32) bool {
    return rl.IsKeyPressed(key) || rl.IsKeyPressedRepeat(key)
}


func raymenu(options []string) (choice string, result RayMenuResult) {
    state := initialize()
    rg.SetFont(state.Font)
    rg.SetStyle(rg.DEFAULT, rg.TEXT_SIZE, fontSize)
    // TODO kinda dumb with additional initialization here
    originalOrder := make([]matching.Matched, len(options))
    for i := range options {
        originalOrder[i].Idx=i
    }
    cursor := 0
    matched := originalOrder
    var prevInput string
    var input string
    for !rl.WindowShouldClose() {
        rl.BeginDrawing()
        rl.ClearBackground(rl.Black)
        resetBounds()
        bounds := nextBounds()

        isControlDown := rl.IsKeyDown(rl.KeyLeftControl) || rl.IsKeyDown(rl.KeyRightControl)
        alternativeBackspace := isPressedRepeat(rl.KeyH) && isControlDown
        enter := (rl.IsKeyPressed(rl.KeyY) && isControlDown) ||
            rl.IsKeyPressed(rl.KeyEnter)

        if alternativeBackspace && len(input) > 0 {
            input = input[:len(input)-1]
        }

        rg.TextBox(bounds, &input, 1024, true)
        if prevInput != input {
            if len(input) > 0 {
                matched = matching.FindAll(input, options)
            } else {
                matched = originalOrder
            }
            cursor = 0
            prevInput = input
        }

        { // cursor update
            moveCursorUp := isPressedRepeat(rl.KeyP) && isControlDown
            moveCursorDown := isPressedRepeat(rl.KeyN) && isControlDown
            if moveCursorUp {
                cursor -= 1
            }
            if moveCursorDown {
                cursor += 1
            }
            if cursor >= len(matched) {
                cursor = len(matched) - 1
            }
            if cursor < 0 {
                cursor = 0
            }
        }

        if enter {
            rl.CloseWindow()
            if cursor < len(matched) {
                return options[matched[cursor].Idx], RayMenuResult_Chosen
            }
            return "", RayMenuResult_NoChoice
        }

        for i, match := range matched {
            bounds := nextBounds()
            textBounds := bounds
            textBounds.X += textBounds.Height
            textBounds.Width -= textBounds.Height
            rg.DrawText(
                options[match.Idx],
                textBounds,
                int32(rg.TEXT_ALIGN_LEFT),
                rl.White,
            )

            if i == cursor {
                // TODO if cursor is not visible then keep some offset or make
                // 2d camera so you can scroll through all the options if you
                // want
                rl.DrawCircle(
                    int32(bounds.X)+int32(bounds.Height)/2,
                    int32(bounds.Y)+int32(bounds.Height)/2,
                    max(textBoxHeight / 8, 1),
                    rl.White,
                )
            }
        }
        rl.EndDrawing()
    }

    return "", RayMenuResult_NoChoice
}

var yOffset float32 = 0.0

func resetBounds() {
    yOffset = 0.0
}

func nextBounds() (bounds rl.Rectangle) {
    bounds = rl.Rectangle{X: 0, Y: yOffset, Width: float32(rl.GetScreenWidth()), Height: textBoxHeight}
    yOffset += textBoxHeight
    return
}

func initialize() State {
    rl.SetTraceLogLevel(rl.LogError)
    rl.InitWindow(windowWidth, 0, "raymenu")
    rl.SetWindowState(rl.FlagWindowUndecorated)
    rl.SetTargetFPS(
        int32(
            rl.GetMonitorRefreshRate(
                rl.GetCurrentMonitor(),
            ),
        ),
    )
    monitor := rl.GetCurrentMonitor()
    monitorWidth := rl.GetMonitorWidth(monitor)
    monitorHeight := rl.GetMonitorHeight(monitor)
    rl.SetWindowSize(
        windowWidth,
        monitorHeight/2,
    )
    rl.SetWindowPosition(
        monitorWidth/2-rl.GetScreenWidth()/2,
        monitorHeight/2-rl.GetScreenHeight()/2,
    )

    return State{
        Font: rl.LoadFontFromMemory(".ttf", font_tff, fontSize, nil),
    }
}