package editor

import (
	"os"

	"git.akyoto.dev/cli/dash/core"
	"github.com/gdamore/tcell/v2"
	"github.com/rivo/tview"
)

type Editor struct {
	Pages    *tview.Pages
	Source   *tview.TextArea
	Result   *tview.TextView
	FilePath string
	IsDirty  bool
}

func New(app *tview.Application, filePath string) *Editor {
	e := &Editor{
		FilePath: filePath,
	}

	e.Pages = tview.NewPages()
	e.Pages.SetBackgroundColor(tcell.ColorDefault)

	source := e.newSourceEditor()
	result := e.newResult()

	e.Pages.AddPage("Source", source, true, false)
	e.Pages.AddPage("Result", result, true, true)

	return e
}

func (e *Editor) toggle() {
	front, _ := e.Pages.GetFrontPage()

	switch front {
	case "Source":
		e.Pages.SwitchToPage("Result")
	case "Result":
		e.Pages.SwitchToPage("Source")
	}
}

func (e *Editor) newSourceEditor() *tview.TextArea {
	e.Source = tview.NewTextArea()
	e.Source.SetBackgroundColor(tcell.ColorDefault)
	e.Source.SetTextStyle(tcell.StyleDefault)
	e.Source.SetBorderPadding(0, 0, 1, 1)
	e.load()

	e.Source.SetChangedFunc(func() {
		e.setDirty(true)
	})

	e.Source.SetInputCapture(func(event *tcell.EventKey) *tcell.EventKey {
		if event.Key() == tcell.KeyESC {
			e.updateResult()
			e.toggle()
			return nil
		}

		if event.Key() == tcell.KeyCtrlS {
			e.save()
			e.updateResult()
			e.toggle()
			return nil
		}

		return event
	})

	return e.Source
}

func (e *Editor) newResult() *tview.TextView {
	e.Result = tview.NewTextView()
	e.Result.SetBackgroundColor(tcell.ColorDefault)
	e.Result.SetTextStyle(tcell.StyleDefault)
	e.Result.SetBorderPadding(0, 0, 1, 1)

	e.Result.SetMouseCapture(func(action tview.MouseAction, event *tcell.EventMouse) (tview.MouseAction, *tcell.EventMouse) {
		if action == tview.MouseLeftClick {
			e.toggle()
		}

		return action, event
	})

	e.Result.SetInputCapture(func(event *tcell.EventKey) *tcell.EventKey {
		switch event.Key() {
		case tcell.KeyEnter:
			e.toggle()
			return nil

		case tcell.KeyRune:
			if event.Rune() == 'i' {
				e.toggle()
				return nil
			}

		case tcell.KeyCtrlS:
			e.save()
			return nil
		}

		return event
	})

	e.updateResult()
	return e.Result
}

func (e *Editor) updateResult() {
	source := e.Source.GetText()
	result := core.Process(source)
	e.Result.SetText(result)
}

func (e *Editor) setDirty(dirty bool) {
	e.IsDirty = dirty

	if dirty {
		e.Source.SetBackgroundColor(tcell.ColorRed)
	} else {
		e.Source.SetBackgroundColor(tcell.ColorDefault)
	}
}

func (e *Editor) load() {
	source := "Press Enter to edit.\nPress Esc to preview.\nPress Ctrl + S to save.\n\n{whoami}@{hostname}"
	data, err := os.ReadFile(e.FilePath)

	if err == nil {
		source = string(data)
	}

	e.Source.SetText(source, true)
}

func (e *Editor) save() {
	if !e.IsDirty {
		return
	}

	source := e.Source.GetText()
	err := os.WriteFile(e.FilePath, []byte(source), 0600)

	if err != nil {
		panic(err)
	}

	e.setDirty(false)
}