package main

import (
	"fmt"
	"math/rand"
	"os"
	"sort"
	"strings"

	qt "github.com/mappu/miqt/qt6"
	"github.com/mappu/miqt/qt6/mainthread"
)

func formatButtonText(s string) string {
	// Escape & used as an alt-accelerator
	s = strings.ReplaceAll(s, `&`, `&&`)

	// Replace " - " with newlines
	s = strings.ReplaceAll(s, ` - `, "\n")
	return s
}

func main() {

	qt.NewQApplication(os.Args)
	appName := "SortVote"
	qt.QCoreApplication_SetApplicationName(appName)

	if len(os.Args) < 2 {
		qt.QMessageBox_Critical(nil, appName, "Usage: ./sortvote filename.txt")
		os.Exit(1)
	}

	b, err := os.ReadFile(os.Args[1])
	if err != nil {
		qt.QMessageBox_Critical(nil, appName, fmt.Sprintf("Error reading file %q: %s", os.Args[1], err.Error()))
		os.Exit(1)
	}

	file_lines := strings.Split(string(b), "\n")
	entries := make([]string, 0, len(file_lines))
	for _, line := range file_lines {
		if len(line) > 0 && line[0] != '#' {
			entries = append(entries, line)
		}
	}

	// Start with a randomized order for fairness

	for i := range entries {
		j := rand.Intn(i + 1)
		entries[i], entries[j] = entries[j], entries[i]
	}

	//

	ui := NewMainWindowUi()
	ui.MainWindow.SetWindowTitle(os.Args[1] + " - " + appName)

	ui.infoArea.AddItem(fmt.Sprintf("Sorting %d entries", len(entries)))
	ui.infoArea.AddItem("Use [Q] and [Z] to select with the keyboard")
	ui.infoArea.ScrollToBottom()

	active := true
	ret := make(chan bool, 0)
	ui.b1.OnClicked(func() { // Set up click handlers only once
		ret <- true
	})
	ui.b2.OnClicked(func() {
		ret <- false
	})

	ui.MainWindow.OnKeyPressEvent(func(super func(event *qt.QKeyEvent), event *qt.QKeyEvent) {
		if !active {
			super(event)
			return
		}

		keytext := strings.ToLower(event.Text())
		if keytext == `q` {
			ret <- true

		} else if keytext == `z` {
			ret <- false

		} else { // not our event
			super(event)
		}

	})

	ui.MainWindow.Show()

	ui.infoArea.SetFocusPolicy(qt.NoFocus) // prevent stealing keyboard input

	comparisons := 0

	go func() {
		sort.SliceStable(entries, func(i, j int) bool {

			// Towards the end, sort.SliceStable has the pattern of putting one
			// entry in the top button all the time
			// Maybe shuffle them
			shuf := (rand.Int()%2 == 0)
			if shuf {
				i, j = j, i
			}

			mainthread.Wait(func() {
				comparisons++

				ui.infoArea.AddItem(fmt.Sprintf("Comparison #%d", comparisons))
				ui.infoArea.ScrollToBottom()

				ui.b1.SetText(formatButtonText(entries[i]))
				ui.b2.SetText(formatButtonText(entries[j]))
			})

			if shuf {
				return !<-ret
			}
			return <-ret
		})
		active = false

		mainthread.Start(func() {
			ui.b1.SetVisible(false)
			ui.b2.SetVisible(false)

			// Sorting 39 entries took 77 comparisons
			// Finished sorting 37 entries in 219 comparisons
			// 37 x log_2(37) = 192 so we are 15% over(?)

			ui.infoArea.AddItem(fmt.Sprintf("Finished sorting %d entries in %d comparisons", len(entries), comparisons))

			for i, ent := range entries {
				ui.infoArea.AddItem(fmt.Sprintf("%02d. %s", i+1, ent))
				ui.infoArea.ScrollToBottom()
			}
		})
	}()

	qt.QApplication_Exec()
}