package theme

import "image"
import "bytes"
import _ "embed"
import _ "image/png"
import "image/color"
import "golang.org/x/image/font"
import "git.tebibyte.media/sashakoshka/tomo/artist"
import "git.tebibyte.media/sashakoshka/tomo/canvas"
import "git.tebibyte.media/sashakoshka/tomo/defaultfont"
import "git.tebibyte.media/sashakoshka/tomo/artist/patterns"

//go:embed assets/wintergreen.png
var defaultAtlasBytes []byte
var defaultAtlas      canvas.Canvas
var defaultTextures   [8][10]artist.Pattern

func atlasCell (col, row int, border artist.Inset) {
	bounds := image.Rect(0, 0, 16, 16).Add(image.Pt(col, row).Mul(16))
	defaultTextures[col][row] = patterns.Border {
		Canvas: canvas.Cut(defaultAtlas, bounds),
		Inset:  border,
	}
}

func atlasCol (col int, border artist.Inset) {
	for index, _ := range defaultTextures[col] {
		atlasCell(col, index, border)
	}
}

func init () {
	defaultAtlasImage, _, _ := image.Decode(bytes.NewReader(defaultAtlasBytes))
	defaultAtlas = canvas.FromImage(defaultAtlasImage)

	// PatternDead
	atlasCol(0, artist.Inset { })
	// PatternRaised
	atlasCol(1, artist.Inset { 6, 6, 6, 6 }) // broken
	// PatternSunken
	atlasCol(2, artist.Inset { 4, 4, 4, 4 })
	// PatternPinboard
	atlasCol(3, artist.Inset { 2, 2, 2, 2 })
	// PatternButton
	atlasCol(4, artist.Inset { 6, 6, 6, 6 }) // broken
	// PatternInput
	atlasCol(5, artist.Inset { 4, 4, 4, 4 })
	// PatternGutter
	atlasCol(6, artist.Inset { 4, 4, 4, 4 })
	// PatternHandle
	atlasCol(7, artist.Inset { 6, 6, 6, 6 }) // broken
}

// Default is the default theme.
type Default struct { }

// FontFace returns the default font face.
func (Default) FontFace (style FontStyle, size FontSize, c Case) font.Face {
	switch style {
	case FontStyleBold:
		return defaultfont.FaceBold
	case FontStyleItalic:
		return defaultfont.FaceItalic
	case FontStyleBoldItalic:
		return defaultfont.FaceBoldItalic
	default:
		return defaultfont.FaceRegular
	}
}

// Icon returns an icon from the default set corresponding to the given name.
func (Default) Icon (string, IconSize, Case) canvas.Image {
	// TODO
	return nil
}

// Pattern returns a pattern from the default theme corresponding to the given
// pattern ID.
func (Default) Pattern (id Pattern, state State, c Case) artist.Pattern {
	offset := 0; switch {
	case state.Disabled:                 offset = 1
	case state.Focused && state.Pressed: offset = 6
	case state.Focused && state.On:      offset = 7
	case state.Invalid && state.Pressed: offset = 8
	case state.Invalid && state.On:      offset = 9
	case state.Invalid:                  offset = 5
	case state.Focused:                  offset = 4
	case state.Pressed:                  offset = 2
	case state.On:                       offset = 3
	}

	switch id {
	case PatternBackground: return patterns.Uhex(0xaaaaaaFF)
	case PatternDead:       return defaultTextures[0][offset]
	case PatternRaised:     return defaultTextures[1][offset]
	case PatternSunken:     return defaultTextures[2][offset]
	case PatternPinboard:   return defaultTextures[3][offset]
	case PatternButton:     return defaultTextures[4][offset]
	case PatternInput:      return defaultTextures[5][offset]
	case PatternGutter:     return defaultTextures[6][offset]
	case PatternHandle:     return defaultTextures[7][offset]
	default:                return patterns.Uhex(0xFF00FFFF)
	}
}

func (Default) Color (id Color, state State, c Case) color.RGBA {
	if state.Disabled {
		return artist.Hex(0x444444FF)
	} else {
		switch id {
		case ColorAccent:     return artist.Hex(0x408090FF)
		case ColorForeground: return artist.Hex(0x000000FF)
		default:              return artist.Hex(0x888888FF)
		}
	}
}

// Padding returns the default padding value for the given pattern.
func (Default) Padding (id Pattern, c Case) artist.Inset {
	switch id {
	case PatternSunken:
		if c == C("basic", "list") {
			return artist.Inset { 2, 2, 2, 2 }
		} else {
			return artist.Inset { 8, 8, 8, 8 }
		}
	case PatternGutter:     return artist.Inset { }
	default:                return artist.Inset { 8, 8, 8, 8 }
	}
}

// Margin returns the default margin value for the given pattern.
func (Default) Margin (id Pattern, c Case) image.Point {
	return image.Pt(8, 8)
}

// Hints returns rendering optimization hints for a particular pattern.
// These are optional, but following them may result in improved
// performance.
func (Default) Hints (pattern Pattern, c Case) (hints Hints) {
	return
}

// Sink returns the default sink vector for the given pattern.
func (Default) Sink (pattern Pattern, c Case) image.Point {
	return image.Point { 1, 1 }
}