package gioui

import (
	"fmt"
	"image"
	"io"
	"path/filepath"
	"sync"
	"time"

	"gioui.org/app"
	"gioui.org/io/event"
	"gioui.org/io/key"
	"gioui.org/io/system"
	"gioui.org/io/transfer"
	"gioui.org/layout"
	"gioui.org/op"
	"gioui.org/op/clip"
	"gioui.org/op/paint"
	"gioui.org/text"
	"gioui.org/widget/material"
	"gioui.org/x/explorer"
	"github.com/vsariola/sointu/tracker"
)

var canQuit = true // set to false in init() if plugin tag is enabled

type (
	Tracker struct {
		Theme                 *material.Theme
		OctaveNumberInput     *NumberInput
		InstrumentVoices      *NumberInput
		TopHorizontalSplit    *Split
		BottomHorizontalSplit *Split
		VerticalSplit         *Split
		KeyPlaying            map[key.Name]tracker.NoteID
		MidiNotePlaying       []byte
		PopupAlert            *PopupAlert

		SaveChangesDialog *Dialog
		WaveTypeDialog    *Dialog

		ModalDialog      layout.Widget
		InstrumentEditor *InstrumentEditor
		OrderEditor      *OrderEditor
		TrackEditor      *NoteEditor
		Explorer         *explorer.Explorer
		Exploring        bool
		SongPanel        *SongPanel

		filePathString tracker.String

		quitWG      sync.WaitGroup
		execChan    chan func()
		preferences Preferences

		*tracker.Model
	}

	C = layout.Context
	D = layout.Dimensions
)

const (
	ConfirmQuit = iota
	ConfirmLoad
	ConfirmNew
)

func NewTracker(model *tracker.Model) *Tracker {
	t := &Tracker{
		Theme:             material.NewTheme(),
		OctaveNumberInput: NewNumberInput(model.Octave().Int()),
		InstrumentVoices:  NewNumberInput(model.InstrumentVoices().Int()),

		TopHorizontalSplit:    &Split{Ratio: -.5},
		BottomHorizontalSplit: &Split{Ratio: -.6},
		VerticalSplit:         &Split{Axis: layout.Vertical},

		KeyPlaying:        make(map[key.Name]tracker.NoteID),
		MidiNotePlaying:   make([]byte, 0, 32),
		SaveChangesDialog: NewDialog(model.SaveSong(), model.DiscardSong(), model.Cancel()),
		WaveTypeDialog:    NewDialog(model.ExportInt16(), model.ExportFloat(), model.Cancel()),
		InstrumentEditor:  NewInstrumentEditor(model),
		OrderEditor:       NewOrderEditor(model),
		TrackEditor:       NewNoteEditor(model),
		SongPanel:         NewSongPanel(model),

		Model: model,

		filePathString: model.FilePath().String(),
		preferences:    MakePreferences(),
	}
	t.Theme.Shaper = text.NewShaper(text.WithCollection(fontCollection))
	t.PopupAlert = NewPopupAlert(model.Alerts(), t.Theme.Shaper)
	if t.preferences.YmlError != nil {
		model.Alerts().Add(
			fmt.Sprintf("Preferences YML Error: %s", t.preferences.YmlError),
			tracker.Warning,
		)
	}
	t.Theme.Palette.Fg = primaryColor
	t.Theme.Palette.ContrastFg = black
	t.TrackEditor.scrollTable.Focus()
	t.quitWG.Add(1)
	return t
}

func (t *Tracker) Main() {
	titleFooter := ""
	w := t.newWindow()
	t.InstrumentEditor.Focus()
	recoveryTicker := time.NewTicker(time.Second * 30)
	t.Explorer = explorer.NewExplorer(w)
	// Make a channel to read window events from.
	events := make(chan event.Event)
	// Make a channel to signal the end of processing a window event.
	acks := make(chan struct{})
	go eventLoop(w, events, acks)
	var ops op.Ops
	for {
		select {
		case e := <-t.Broker().ToModel:
			t.ProcessMsg(e)
			w.Invalidate()
		case e := <-events:
			switch e := e.(type) {
			case app.DestroyEvent:
				acks <- struct{}{}
				if canQuit {
					t.Quit().Do()
				}
				if !t.Quitted() {
					// TODO: uh oh, there's no way of canceling the destroyevent in gioui? so we create a new window just to show the dialog
					w = t.newWindow()
					t.Explorer = explorer.NewExplorer(w)
					go eventLoop(w, events, acks)
				}
			case app.FrameEvent:
				if titleFooter != t.filePathString.Value() {
					titleFooter = t.filePathString.Value()
					if titleFooter != "" {
						w.Option(app.Title(fmt.Sprintf("Sointu Tracker - %v", titleFooter)))
					} else {
						w.Option(app.Title("Sointu Tracker"))
					}
				}
				gtx := app.NewContext(&ops, e)
				if t.SongPanel.PlayingBtn.Bool.Value() && t.SongPanel.FollowBtn.Bool.Value() {
					t.TrackEditor.scrollTable.RowTitleList.CenterOn(t.PlaySongRow())
				}
				t.Layout(gtx, w)
				e.Frame(gtx.Ops)
				acks <- struct{}{}
			default:
				acks <- struct{}{}
			}
		case <-recoveryTicker.C:
			t.SaveRecovery()
		}
		if t.Quitted() {
			break
		}
	}
	recoveryTicker.Stop()
	w.Perform(system.ActionClose)
	t.SaveRecovery()
	t.quitWG.Done()
}

func (t *Tracker) newWindow() *app.Window {
	w := new(app.Window)
	w.Option(app.Title("Sointu Tracker"))
	w.Option(app.Size(t.preferences.WindowSize()))
	if t.preferences.Window.Maximized {
		w.Option(app.Maximized.Option())
	}
	return w
}

func eventLoop(w *app.Window, events chan<- event.Event, acks <-chan struct{}) {
	// Iterate window events, sending each to the old event loop and waiting for
	// a signal that processing is complete before iterating again.
	for {
		ev := w.Event()
		events <- ev
		<-acks
		if _, ok := ev.(app.DestroyEvent); ok {
			return
		}
	}
}

func (t *Tracker) WaitQuitted() {
	t.quitWG.Wait()
}

func (t *Tracker) Layout(gtx layout.Context, w *app.Window) {
	paint.FillShape(gtx.Ops, backgroundColor, clip.Rect(image.Rect(0, 0, gtx.Constraints.Max.X, gtx.Constraints.Max.Y)).Op())
	if t.InstrumentEditor.enlargeBtn.Bool.Value() {
		t.layoutTop(gtx)
	} else {
		t.VerticalSplit.Layout(gtx,
			t.layoutTop,
			t.layoutBottom)
	}
	t.PopupAlert.Layout(gtx)
	t.showDialog(gtx)
	// this is the top level input handler for the whole app
	// it handles all the global key events and clipboard events
	// we need to tell gio that we handle tabs too; otherwise
	// it will steal them for focus switching
	for {
		ev, ok := gtx.Event(
			key.Filter{Name: "", Optional: key.ModAlt | key.ModCommand | key.ModShift | key.ModShortcut | key.ModSuper},
			key.Filter{Name: key.NameTab, Optional: key.ModShift},
			transfer.TargetFilter{Target: t, Type: "application/text"},
		)
		if !ok {
			break
		}
		switch e := ev.(type) {
		case key.Event:
			t.KeyEvent(e, gtx)
		case transfer.DataEvent:
			t.ReadSong(e.Open())
		}
	}

}

func (t *Tracker) showDialog(gtx C) {
	if t.Exploring {
		return
	}
	switch t.Dialog() {
	case tracker.NewSongChanges, tracker.OpenSongChanges, tracker.QuitChanges:
		dstyle := ConfirmDialog(gtx, t.Theme, t.SaveChangesDialog, "Save changes to song?", "Your changes will be lost if you don't save them.")
		dstyle.OkStyle.Text = "Save"
		dstyle.AltStyle.Text = "Don't save"
		dstyle.Layout(gtx)
	case tracker.Export:
		dstyle := ConfirmDialog(gtx, t.Theme, t.WaveTypeDialog, "", "Export .wav in int16 or float32 sample format?")
		dstyle.OkStyle.Text = "Int16"
		dstyle.AltStyle.Text = "Float32"
		dstyle.Layout(gtx)
	case tracker.OpenSongOpenExplorer:
		t.explorerChooseFile(t.ReadSong, ".yml", ".json")
	case tracker.NewSongSaveExplorer, tracker.OpenSongSaveExplorer, tracker.QuitSaveExplorer, tracker.SaveAsExplorer:
		filename := t.filePathString.Value()
		if filename == "" {
			filename = "song.yml"
		}
		t.explorerCreateFile(t.WriteSong, filename)
	case tracker.ExportFloatExplorer, tracker.ExportInt16Explorer:
		filename := "song.wav"
		if p := t.filePathString.Value(); p != "" {
			filename = p[:len(p)-len(filepath.Ext(p))] + ".wav"
		}
		t.explorerCreateFile(func(wc io.WriteCloser) {
			t.WriteWav(wc, t.Dialog() == tracker.ExportInt16Explorer)
		}, filename)
	}
}

func (t *Tracker) explorerChooseFile(success func(io.ReadCloser), extensions ...string) {
	t.Exploring = true
	go func() {
		file, err := t.Explorer.ChooseFile(extensions...)
		t.Broker().ToModel <- tracker.MsgToModel{Data: func() {
			t.Exploring = false
			if err == nil {
				success(file)
			} else {
				t.Cancel().Do()
			}
		}}
	}()
}

func (t *Tracker) explorerCreateFile(success func(io.WriteCloser), filename string) {
	t.Exploring = true
	go func() {
		file, err := t.Explorer.CreateFile(filename)
		t.Broker().ToModel <- tracker.MsgToModel{Data: func() {
			t.Exploring = false
			if err == nil {
				success(file)
			} else {
				t.Cancel().Do()
			}
		}}
	}()
}

func (t *Tracker) layoutBottom(gtx layout.Context) layout.Dimensions {
	return t.BottomHorizontalSplit.Layout(gtx,
		func(gtx C) D {
			return t.OrderEditor.Layout(gtx, t)
		},
		func(gtx C) D {
			return t.TrackEditor.Layout(gtx, t)
		},
	)
}

func (t *Tracker) layoutTop(gtx layout.Context) layout.Dimensions {
	return t.TopHorizontalSplit.Layout(gtx,
		func(gtx C) D {
			return t.SongPanel.Layout(gtx, t)
		},
		func(gtx C) D {
			return t.InstrumentEditor.Layout(gtx, t)
		},
	)
}

/// Event Handling (for UI updates when playing etc.)

func (t *Tracker) ProcessMessage(msg interface{}) {
	switch msg.(type) {
	case tracker.StartPlayMsg:
		fmt.Println("Tracker received StartPlayMsg")
	case tracker.RecordingMsg:
		fmt.Println("Tracker received RecordingMsg")
	default:
		break
	}
}

func (t *Tracker) ProcessEvent(event tracker.MIDINoteEvent) {
	// MIDINoteEvent can be only NoteOn / NoteOff, i.e. its On field
	if event.On {
		t.addToMidiNotePlaying(event.Note)
	} else {
		t.removeFromMidiNotePlaying(event.Note)
	}
	t.TrackEditor.HandleMidiInput(t)
}

func (t *Tracker) addToMidiNotePlaying(note byte) {
	for _, n := range t.MidiNotePlaying {
		if n == note {
			return
		}
	}
	t.MidiNotePlaying = append(t.MidiNotePlaying, note)
}

func (t *Tracker) removeFromMidiNotePlaying(note byte) {
	for i, n := range t.MidiNotePlaying {
		if n == note {
			t.MidiNotePlaying = append(
				t.MidiNotePlaying[:i],
				t.MidiNotePlaying[i+1:]...,
			)
		}
	}
}