package gioui

import (
	"fmt"
	"image"
	"strings"

	"gioui.org/f32"
	"gioui.org/io/pointer"
	"gioui.org/layout"
	"gioui.org/op"
	"gioui.org/op/clip"
	"gioui.org/op/paint"
	"gioui.org/text"
	"gioui.org/unit"
	"gioui.org/widget"
	"github.com/vsariola/sointu/tracker"
)

const patternCellHeight = 16
const patternCellWidth = 16
const patternRowMarkerWidth = 30

var patternPointerTag = false

func (t *Tracker) layoutPatterns(gtx C) D {
	defer op.Save(gtx.Ops).Load()
	clip.Rect{Max: gtx.Constraints.Max}.Add(gtx.Ops)
	for _, ev := range gtx.Events(&patternPointerTag) {
		e, ok := ev.(pointer.Event)
		if !ok {
			continue
		}
		if e.Type == pointer.Press {
			t.SetEditMode(tracker.EditPatterns)
		}
	}
	rect := image.Rect(0, 0, gtx.Constraints.Max.X, gtx.Constraints.Max.Y)
	pointer.Rect(rect).Add(gtx.Ops)
	pointer.InputOp{Tag: &patternPointerTag,
		Types: pointer.Press,
	}.Add(gtx.Ops)
	patternRect := tracker.SongRect{
		Corner1: tracker.SongPoint{SongRow: tracker.SongRow{Pattern: t.Cursor().Pattern}, Track: t.Cursor().Track},
		Corner2: tracker.SongPoint{SongRow: tracker.SongRow{Pattern: t.SelectionCorner().Pattern}, Track: t.SelectionCorner().Track},
	}

	// draw the single letter titles for tracks
	{
		gtx := gtx
		curVoice := 0
		stack := op.Save(gtx.Ops)
		op.Offset(f32.Pt(patternRowMarkerWidth, 0)).Add(gtx.Ops)
		gtx.Constraints = layout.Exact(image.Pt(patternCellWidth, patternCellHeight))
		for _, track := range t.Song().Score.Tracks {
			instr, err := t.Song().Patch.InstrumentForVoice(curVoice)
			var title string
			if err == nil && len(t.Song().Patch[instr].Name) > 0 {
				title = string(t.Song().Patch[instr].Name[0])
			} else {
				title = "I"
			}
			LabelStyle{Alignment: layout.N, Text: title, FontSize: unit.Dp(12), Color: mediumEmphasisTextColor}.Layout(gtx)
			op.Offset(f32.Pt(patternCellWidth, 0)).Add(gtx.Ops)
			curVoice += track.NumVoices
		}
		stack.Load()
	}
	op.Offset(f32.Pt(0, patternCellHeight)).Add(gtx.Ops)
	gtx.Constraints.Max.Y -= patternCellHeight
	gtx.Constraints.Min.Y -= patternCellHeight
	element := func(gtx C, j int) D {
		if playPos, ok := t.player.Position(); ok && j == playPos.Pattern {
			paint.FillShape(gtx.Ops, patternPlayColor, clip.Rect{Max: image.Pt(gtx.Constraints.Max.X, patternCellHeight)}.Op())
		}
		paint.ColorOp{Color: rowMarkerPatternTextColor}.Add(gtx.Ops)
		widget.Label{}.Layout(gtx, textShaper, trackerFont, trackerFontSize, strings.ToUpper(fmt.Sprintf("%02x", j)))
		stack := op.Save(gtx.Ops)
		op.Offset(f32.Pt(patternRowMarkerWidth, 0)).Add(gtx.Ops)
		for i, track := range t.Song().Score.Tracks {
			paint.FillShape(gtx.Ops, patternCellColor, clip.Rect{Min: image.Pt(1, 1), Max: image.Pt(patternCellWidth-1, patternCellHeight-1)}.Op())
			paint.ColorOp{Color: patternTextColor}.Add(gtx.Ops)
			if j >= 0 && j < len(track.Order) && track.Order[j] >= 0 {
				gtx := gtx
				gtx.Constraints.Max.X = patternCellWidth
				op.Offset(f32.Pt(0, -2)).Add(gtx.Ops)
				widget.Label{Alignment: text.Middle}.Layout(gtx, textShaper, trackerFont, trackerFontSize, patternIndexToString(track.Order[j]))
				op.Offset(f32.Pt(0, 2)).Add(gtx.Ops)
			}
			point := tracker.SongPoint{Track: i, SongRow: tracker.SongRow{Pattern: j}}
			if t.EditMode() == tracker.EditPatterns || t.EditMode() == tracker.EditTracks {
				if patternRect.Contains(point) {
					color := inactiveSelectionColor
					if t.EditMode() == tracker.EditPatterns {
						color = selectionColor
						if point.Pattern == t.Cursor().Pattern && point.Track == t.Cursor().Track {
							color = cursorColor
						}
					}
					paint.FillShape(gtx.Ops, color, clip.Rect{Max: image.Pt(patternCellWidth, patternCellHeight)}.Op())
				}
			}
			op.Offset(f32.Pt(patternCellWidth, 0)).Add(gtx.Ops)
		}
		stack.Load()
		return D{Size: image.Pt(gtx.Constraints.Max.X, patternCellHeight)}
	}
	return layout.Stack{Alignment: layout.NE}.Layout(gtx,
		layout.Expanded(func(gtx C) D {
			return t.PatternOrderList.Layout(gtx, t.Song().Score.Length, element)
		}),
		layout.Expanded(func(gtx C) D {
			return t.PatternOrderScrollBar.Layout(gtx, unit.Dp(10), t.Song().Score.Length, &t.PatternOrderList.Position)
		}),
	)
}

func patternIndexToString(index int) string {
	if index < 0 {
		return ""
	} else if index < 10 {
		return string('0' + byte(index))
	}
	return string('A' + byte(index-10))
}