package styles

import (
	"fmt"
	"image/color"
	"strings"

	"charm.land/bubbles/v2/filepicker"
	"charm.land/bubbles/v2/help"
	"charm.land/bubbles/v2/textarea"
	"charm.land/bubbles/v2/textinput"
	tea "charm.land/bubbletea/v2"
	"charm.land/glamour/v2/ansi"
	"charm.land/lipgloss/v2"
	"git.secluded.site/crush/internal/tui/exp/diffview"
	"github.com/charmbracelet/x/exp/charmtone"
	"github.com/lucasb-eyer/go-colorful"
	"github.com/rivo/uniseg"
)

const (
	defaultListIndent      = 2
	defaultListLevelIndent = 4
	defaultMargin          = 2
)

type Theme struct {
	Name   string
	IsDark bool

	Primary   color.Color
	Secondary color.Color
	Tertiary  color.Color
	Accent    color.Color

	BgBase        color.Color
	BgBaseLighter color.Color
	BgSubtle      color.Color
	BgOverlay     color.Color

	FgBase      color.Color
	FgMuted     color.Color
	FgHalfMuted color.Color
	FgSubtle    color.Color
	FgSelected  color.Color

	Border      color.Color
	BorderFocus color.Color

	Success color.Color
	Error   color.Color
	Warning color.Color
	Info    color.Color

	// Colors
	// White
	White color.Color

	// Blues
	BlueLight color.Color
	BlueDark  color.Color
	Blue      color.Color

	// Yellows
	Yellow color.Color
	Citron color.Color

	// Greens
	Green      color.Color
	GreenDark  color.Color
	GreenLight color.Color

	// Reds
	Red      color.Color
	RedDark  color.Color
	RedLight color.Color
	Cherry   color.Color

	// Markdown colors (theme-aware for accessibility).
	MdText          color.Color // Document text
	MdHeading       color.Color // Heading color
	MdH6            color.Color // H6 color
	MdHRule         color.Color // Horizontal rule
	MdLink          color.Color // Link URL
	MdLinkText      color.Color // Link text
	MdImage         color.Color // Image URL
	MdImageText     color.Color // Image alt text
	MdCodeFg        color.Color // Inline code foreground
	MdCodeBg        color.Color // Inline code background
	MdCodeBlockFg   color.Color // Code block text
	MdCodeBlockBg   color.Color // Code block background
	MdComment       color.Color // Code comment
	MdKeyword       color.Color // Keyword
	MdKeywordAlt    color.Color // Keyword reserved/namespace
	MdKeywordType   color.Color // Type keyword
	MdOperator      color.Color // Operator
	MdPunctuation   color.Color // Punctuation
	MdName          color.Color // Name/identifier
	MdNameBuiltin   color.Color // Builtin name
	MdNameTag       color.Color // Tag name
	MdNameAttr      color.Color // Attribute name
	MdNameClass     color.Color // Class name
	MdNameDecorator color.Color // Decorator
	MdNameFunc      color.Color // Function name
	MdNumber        color.Color // Literal number
	MdString        color.Color // Literal string
	MdStringEscape  color.Color // String escape
	MdDeleted       color.Color // Deleted text
	MdInserted      color.Color // Inserted text
	MdSubheading    color.Color // Subheading
	MdError         color.Color // Error foreground
	MdErrorBg       color.Color // Error background

	// Diff colors (theme-aware).
	DiffInsertFg     color.Color // Insert line number fg
	DiffInsertBg     color.Color // Insert line number bg
	DiffInsertSymBg  color.Color // Insert symbol bg
	DiffInsertCodeBg color.Color // Insert code bg
	DiffDeleteFg     color.Color // Delete line number fg
	DiffDeleteBg     color.Color // Delete line number bg
	DiffDeleteSymBg  color.Color // Delete symbol bg
	DiffDeleteCodeBg color.Color // Delete code bg

	// Text selection.
	TextSelection lipgloss.Style

	// LSP and MCP status indicators.
	ItemOfflineIcon lipgloss.Style
	ItemBusyIcon    lipgloss.Style
	ItemErrorIcon   lipgloss.Style
	ItemOnlineIcon  lipgloss.Style

	// Editor: Yolo Mode.
	YoloIconFocused lipgloss.Style
	YoloIconBlurred lipgloss.Style
	YoloDotsFocused lipgloss.Style
	YoloDotsBlurred lipgloss.Style

	// oAuth Chooser.
	AuthBorderSelected   lipgloss.Style
	AuthTextSelected     lipgloss.Style
	AuthBorderUnselected lipgloss.Style
	AuthTextUnselected   lipgloss.Style

	styles *Styles
}

type Styles struct {
	Base         lipgloss.Style
	SelectedBase lipgloss.Style

	Title        lipgloss.Style
	Subtitle     lipgloss.Style
	Text         lipgloss.Style
	TextSelected lipgloss.Style
	Muted        lipgloss.Style
	Subtle       lipgloss.Style

	Success lipgloss.Style
	Error   lipgloss.Style
	Warning lipgloss.Style
	Info    lipgloss.Style

	// Markdown & Chroma
	Markdown ansi.StyleConfig

	// Inputs
	TextInput textinput.Styles
	TextArea  textarea.Styles

	// Help
	Help help.Styles

	// Diff
	Diff diffview.Style

	// FilePicker
	FilePicker filepicker.Styles
}

func (t *Theme) S() *Styles {
	if t.styles == nil {
		t.styles = t.buildStyles()
	}
	return t.styles
}

func (t *Theme) buildStyles() *Styles {
	base := lipgloss.NewStyle().
		Foreground(t.FgBase)
	return &Styles{
		Base: base,

		SelectedBase: base.Background(t.Primary),

		Title: base.
			Foreground(t.Accent).
			Bold(true),

		Subtitle: base.
			Foreground(t.Secondary).
			Bold(true),

		Text:         base,
		TextSelected: base.Background(t.Primary).Foreground(t.FgSelected),

		Muted: base.Foreground(t.FgMuted),

		Subtle: base.Foreground(t.FgSubtle),

		Success: base.Foreground(t.Success),

		Error: base.Foreground(t.Error),

		Warning: base.Foreground(t.Warning),

		Info: base.Foreground(t.Info),

		TextInput: textinput.Styles{
			Focused: textinput.StyleState{
				Text:        base,
				Placeholder: base.Foreground(t.FgSubtle),
				Prompt:      base.Foreground(t.Tertiary),
				Suggestion:  base.Foreground(t.FgSubtle),
			},
			Blurred: textinput.StyleState{
				Text:        base.Foreground(t.FgMuted),
				Placeholder: base.Foreground(t.FgSubtle),
				Prompt:      base.Foreground(t.FgMuted),
				Suggestion:  base.Foreground(t.FgSubtle),
			},
			Cursor: textinput.CursorStyle{
				Color: t.Secondary,
				Shape: tea.CursorBlock,
				Blink: true,
			},
		},
		TextArea: textarea.Styles{
			Focused: textarea.StyleState{
				Base:             base,
				Text:             base,
				LineNumber:       base.Foreground(t.FgSubtle),
				CursorLine:       base,
				CursorLineNumber: base.Foreground(t.FgSubtle),
				Placeholder:      base.Foreground(t.FgSubtle),
				Prompt:           base.Foreground(t.Tertiary),
			},
			Blurred: textarea.StyleState{
				Base:             base,
				Text:             base.Foreground(t.FgMuted),
				LineNumber:       base.Foreground(t.FgMuted),
				CursorLine:       base,
				CursorLineNumber: base.Foreground(t.FgMuted),
				Placeholder:      base.Foreground(t.FgSubtle),
				Prompt:           base.Foreground(t.FgMuted),
			},
			Cursor: textarea.CursorStyle{
				Color: t.Secondary,
				Shape: tea.CursorBlock,
				Blink: true,
			},
		},

		Markdown: ansi.StyleConfig{
			Document: ansi.StyleBlock{
				StylePrimitive: ansi.StylePrimitive{
					// BlockPrefix: "\n",
					// BlockSuffix: "\n",
					Color: stringPtr(ToHex(t.MdText)),
				},
				// Margin: uintPtr(defaultMargin),
			},
			BlockQuote: ansi.StyleBlock{
				StylePrimitive: ansi.StylePrimitive{},
				Indent:         uintPtr(1),
				IndentToken:    stringPtr("│ "),
			},
			List: ansi.StyleList{
				LevelIndent: defaultListIndent,
			},
			Heading: ansi.StyleBlock{
				StylePrimitive: ansi.StylePrimitive{
					BlockSuffix: "\n",
					Color:       stringPtr(ToHex(t.MdHeading)),
					Bold:        boolPtr(true),
				},
			},
			H1: ansi.StyleBlock{
				StylePrimitive: ansi.StylePrimitive{
					Prefix:          " ",
					Suffix:          " ",
					Color:           stringPtr(charmtone.Zest.Hex()),
					BackgroundColor: stringPtr(charmtone.Charple.Hex()),
					Bold:            boolPtr(true),
				},
			},
			H2: ansi.StyleBlock{
				StylePrimitive: ansi.StylePrimitive{
					Prefix: "## ",
				},
			},
			H3: ansi.StyleBlock{
				StylePrimitive: ansi.StylePrimitive{
					Prefix: "### ",
				},
			},
			H4: ansi.StyleBlock{
				StylePrimitive: ansi.StylePrimitive{
					Prefix: "#### ",
				},
			},
			H5: ansi.StyleBlock{
				StylePrimitive: ansi.StylePrimitive{
					Prefix: "##### ",
				},
			},
			H6: ansi.StyleBlock{
				StylePrimitive: ansi.StylePrimitive{
					Prefix: "###### ",
					Color:  stringPtr(ToHex(t.MdH6)),
					Bold:   boolPtr(false),
				},
			},
			Strikethrough: ansi.StylePrimitive{
				CrossedOut: boolPtr(true),
			},
			Emph: ansi.StylePrimitive{
				Italic: boolPtr(true),
			},
			Strong: ansi.StylePrimitive{
				Bold: boolPtr(true),
			},
			HorizontalRule: ansi.StylePrimitive{
				Color:  stringPtr(ToHex(t.MdHRule)),
				Format: "\n--------\n",
			},
			Item: ansi.StylePrimitive{
				BlockPrefix: "• ",
			},
			Enumeration: ansi.StylePrimitive{
				BlockPrefix: ". ",
			},
			Task: ansi.StyleTask{
				StylePrimitive: ansi.StylePrimitive{},
				Ticked:         "[✓] ",
				Unticked:       "[ ] ",
			},
			Link: ansi.StylePrimitive{
				Color:     stringPtr(ToHex(t.MdLink)),
				Underline: boolPtr(true),
			},
			LinkText: ansi.StylePrimitive{
				Color: stringPtr(ToHex(t.MdLinkText)),
				Bold:  boolPtr(true),
			},
			Image: ansi.StylePrimitive{
				Color:     stringPtr(ToHex(t.MdImage)),
				Underline: boolPtr(true),
			},
			ImageText: ansi.StylePrimitive{
				Color:  stringPtr(ToHex(t.MdImageText)),
				Format: "Image: {{.text}} →",
			},
			Code: ansi.StyleBlock{
				StylePrimitive: ansi.StylePrimitive{
					Prefix:          " ",
					Suffix:          " ",
					Color:           stringPtr(ToHex(t.MdCodeFg)),
					BackgroundColor: stringPtr(ToHex(t.MdCodeBg)),
				},
			},
			CodeBlock: ansi.StyleCodeBlock{
				StyleBlock: ansi.StyleBlock{
					StylePrimitive: ansi.StylePrimitive{
						Color: stringPtr(ToHex(t.MdCodeBlockFg)),
					},
					Margin: uintPtr(defaultMargin),
				},
				Chroma: &ansi.Chroma{
					Text: ansi.StylePrimitive{
						Color: stringPtr(ToHex(t.MdText)),
					},
					Error: ansi.StylePrimitive{
						Color:           stringPtr(ToHex(t.MdError)),
						BackgroundColor: stringPtr(ToHex(t.MdErrorBg)),
					},
					Comment: ansi.StylePrimitive{
						Color: stringPtr(ToHex(t.MdComment)),
					},
					CommentPreproc: ansi.StylePrimitive{
						Color: stringPtr(ToHex(t.MdComment)),
					},
					Keyword: ansi.StylePrimitive{
						Color: stringPtr(ToHex(t.MdKeyword)),
					},
					KeywordReserved: ansi.StylePrimitive{
						Color: stringPtr(ToHex(t.MdKeywordAlt)),
					},
					KeywordNamespace: ansi.StylePrimitive{
						Color: stringPtr(ToHex(t.MdKeywordAlt)),
					},
					KeywordType: ansi.StylePrimitive{
						Color: stringPtr(ToHex(t.MdKeywordType)),
					},
					Operator: ansi.StylePrimitive{
						Color: stringPtr(ToHex(t.MdOperator)),
					},
					Punctuation: ansi.StylePrimitive{
						Color: stringPtr(ToHex(t.MdPunctuation)),
					},
					Name: ansi.StylePrimitive{
						Color: stringPtr(ToHex(t.MdName)),
					},
					NameBuiltin: ansi.StylePrimitive{
						Color: stringPtr(ToHex(t.MdNameBuiltin)),
					},
					NameTag: ansi.StylePrimitive{
						Color: stringPtr(ToHex(t.MdNameTag)),
					},
					NameAttribute: ansi.StylePrimitive{
						Color: stringPtr(ToHex(t.MdNameAttr)),
					},
					NameClass: ansi.StylePrimitive{
						Color:     stringPtr(ToHex(t.MdNameClass)),
						Underline: boolPtr(true),
						Bold:      boolPtr(true),
					},
					NameDecorator: ansi.StylePrimitive{
						Color: stringPtr(ToHex(t.MdNameDecorator)),
					},
					NameFunction: ansi.StylePrimitive{
						Color: stringPtr(ToHex(t.MdNameFunc)),
					},
					LiteralNumber: ansi.StylePrimitive{
						Color: stringPtr(ToHex(t.MdNumber)),
					},
					LiteralString: ansi.StylePrimitive{
						Color: stringPtr(ToHex(t.MdString)),
					},
					LiteralStringEscape: ansi.StylePrimitive{
						Color: stringPtr(ToHex(t.MdStringEscape)),
					},
					GenericDeleted: ansi.StylePrimitive{
						Color: stringPtr(ToHex(t.MdDeleted)),
					},
					GenericEmph: ansi.StylePrimitive{
						Italic: boolPtr(true),
					},
					GenericInserted: ansi.StylePrimitive{
						Color: stringPtr(ToHex(t.MdInserted)),
					},
					GenericStrong: ansi.StylePrimitive{
						Bold: boolPtr(true),
					},
					GenericSubheading: ansi.StylePrimitive{
						Color: stringPtr(ToHex(t.MdSubheading)),
					},
					Background: ansi.StylePrimitive{
						BackgroundColor: stringPtr(ToHex(t.MdCodeBlockBg)),
					},
				},
			},
			Table: ansi.StyleTable{
				StyleBlock: ansi.StyleBlock{
					StylePrimitive: ansi.StylePrimitive{},
				},
			},
			DefinitionDescription: ansi.StylePrimitive{
				BlockPrefix: "\n ",
			},
		},

		Help: help.Styles{
			ShortKey:       base.Foreground(t.FgMuted),
			ShortDesc:      base.Foreground(t.FgSubtle),
			ShortSeparator: base.Foreground(t.Border),
			Ellipsis:       base.Foreground(t.Border),
			FullKey:        base.Foreground(t.FgMuted),
			FullDesc:       base.Foreground(t.FgSubtle),
			FullSeparator:  base.Foreground(t.Border),
		},

		Diff: diffview.Style{
			DividerLine: diffview.LineStyle{
				LineNumber: lipgloss.NewStyle().
					Foreground(t.FgHalfMuted).
					Background(t.BgBaseLighter),
				Code: lipgloss.NewStyle().
					Foreground(t.FgHalfMuted).
					Background(t.BgBaseLighter),
			},
			MissingLine: diffview.LineStyle{
				LineNumber: lipgloss.NewStyle().
					Background(t.BgBaseLighter),
				Code: lipgloss.NewStyle().
					Background(t.BgBaseLighter),
			},
			EqualLine: diffview.LineStyle{
				LineNumber: lipgloss.NewStyle().
					Foreground(t.FgMuted).
					Background(t.BgBase),
				Code: lipgloss.NewStyle().
					Foreground(t.FgMuted).
					Background(t.BgBase),
			},
			InsertLine: diffview.LineStyle{
				LineNumber: lipgloss.NewStyle().
					Foreground(t.DiffInsertFg).
					Background(t.DiffInsertBg),
				Symbol: lipgloss.NewStyle().
					Foreground(t.DiffInsertFg).
					Background(t.DiffInsertSymBg),
				Code: lipgloss.NewStyle().
					Background(t.DiffInsertCodeBg),
			},
			DeleteLine: diffview.LineStyle{
				LineNumber: lipgloss.NewStyle().
					Foreground(t.DiffDeleteFg).
					Background(t.DiffDeleteBg),
				Symbol: lipgloss.NewStyle().
					Foreground(t.DiffDeleteFg).
					Background(t.DiffDeleteSymBg),
				Code: lipgloss.NewStyle().
					Background(t.DiffDeleteCodeBg),
			},
		},
		FilePicker: filepicker.Styles{
			DisabledCursor:   base.Foreground(t.FgMuted),
			Cursor:           base.Foreground(t.FgBase),
			Symlink:          base.Foreground(t.FgSubtle),
			Directory:        base.Foreground(t.Primary),
			File:             base.Foreground(t.FgBase),
			DisabledFile:     base.Foreground(t.FgMuted),
			DisabledSelected: base.Background(t.BgOverlay).Foreground(t.FgMuted),
			Permission:       base.Foreground(t.FgMuted),
			Selected:         base.Background(t.Primary).Foreground(t.FgBase),
			FileSize:         base.Foreground(t.FgMuted),
			EmptyDirectory:   base.Foreground(t.FgMuted).PaddingLeft(2).SetString("Empty directory"),
		},
	}
}

type Manager struct {
	themes  map[string]*Theme
	current *Theme
}

var defaultManager *Manager

func SetDefaultManager(m *Manager) {
	defaultManager = m
}

func DefaultManager() *Manager {
	if defaultManager == nil {
		defaultManager = NewManager()
	}
	return defaultManager
}

func CurrentTheme() *Theme {
	if defaultManager == nil {
		defaultManager = NewManager()
	}
	return defaultManager.Current()
}

func NewManager() *Manager {
	m := &Manager{
		themes: make(map[string]*Theme),
	}

	dark := NewCharmtoneTheme()
	light := NewLightTheme()
	m.Register(dark)
	m.Register(light)
	m.current = dark // default to dark theme

	return m
}

func (m *Manager) Register(theme *Theme) {
	m.themes[theme.Name] = theme
}

func (m *Manager) Current() *Theme {
	return m.current
}

func (m *Manager) SetTheme(name string) error {
	if theme, ok := m.themes[name]; ok {
		m.current = theme
		return nil
	}
	return fmt.Errorf("theme %s not found", name)
}

func (m *Manager) List() []string {
	names := make([]string, 0, len(m.themes))
	for name := range m.themes {
		names = append(names, name)
	}
	return names
}

// ParseHex converts hex string to color
func ParseHex(hex string) color.Color {
	var r, g, b uint8
	fmt.Sscanf(hex, "#%02x%02x%02x", &r, &g, &b)
	return color.RGBA{R: r, G: g, B: b, A: 255}
}

// ToHex converts a color.Color to hex string.
func ToHex(c color.Color) string {
	r, g, b, _ := c.RGBA()
	return fmt.Sprintf("#%02X%02X%02X", r>>8, g>>8, b>>8)
}

// Alpha returns a color with transparency
func Alpha(c color.Color, alpha uint8) color.Color {
	r, g, b, _ := c.RGBA()
	return color.RGBA{
		R: uint8(r >> 8),
		G: uint8(g >> 8),
		B: uint8(b >> 8),
		A: alpha,
	}
}

// Darken makes a color darker by percentage (0-100)
func Darken(c color.Color, percent float64) color.Color {
	r, g, b, a := c.RGBA()
	factor := 1.0 - percent/100.0
	return color.RGBA{
		R: uint8(float64(r>>8) * factor),
		G: uint8(float64(g>>8) * factor),
		B: uint8(float64(b>>8) * factor),
		A: uint8(a >> 8),
	}
}

// Lighten makes a color lighter by percentage (0-100)
func Lighten(c color.Color, percent float64) color.Color {
	r, g, b, a := c.RGBA()
	factor := percent / 100.0
	return color.RGBA{
		R: uint8(min(255, float64(r>>8)+255*factor)),
		G: uint8(min(255, float64(g>>8)+255*factor)),
		B: uint8(min(255, float64(b>>8)+255*factor)),
		A: uint8(a >> 8),
	}
}

func ForegroundGrad(input string, bold bool, color1, color2 color.Color) []string {
	if input == "" {
		return []string{""}
	}
	t := CurrentTheme()
	if len(input) == 1 {
		style := t.S().Base.Foreground(color1)
		if bold {
			style.Bold(true)
		}
		return []string{style.Render(input)}
	}
	var clusters []string
	gr := uniseg.NewGraphemes(input)
	for gr.Next() {
		clusters = append(clusters, string(gr.Runes()))
	}

	ramp := blendColors(len(clusters), color1, color2)
	for i, c := range ramp {
		style := t.S().Base.Foreground(c)
		if bold {
			style.Bold(true)
		}
		clusters[i] = style.Render(clusters[i])
	}
	return clusters
}

// ApplyForegroundGrad renders a given string with a horizontal gradient
// foreground.
func ApplyForegroundGrad(input string, color1, color2 color.Color) string {
	if input == "" {
		return ""
	}
	var o strings.Builder
	clusters := ForegroundGrad(input, false, color1, color2)
	for _, c := range clusters {
		fmt.Fprint(&o, c)
	}
	return o.String()
}

// ApplyBoldForegroundGrad renders a given string with a horizontal gradient
// foreground.
func ApplyBoldForegroundGrad(input string, color1, color2 color.Color) string {
	if input == "" {
		return ""
	}
	var o strings.Builder
	clusters := ForegroundGrad(input, true, color1, color2)
	for _, c := range clusters {
		fmt.Fprint(&o, c)
	}
	return o.String()
}

// blendColors returns a slice of colors blended between the given keys.
// Blending is done in Hcl to stay in gamut.
func blendColors(size int, stops ...color.Color) []color.Color {
	if len(stops) < 2 {
		return nil
	}

	stopsPrime := make([]colorful.Color, len(stops))
	for i, k := range stops {
		stopsPrime[i], _ = colorful.MakeColor(k)
	}

	numSegments := len(stopsPrime) - 1
	blended := make([]color.Color, 0, size)

	// Calculate how many colors each segment should have.
	segmentSizes := make([]int, numSegments)
	baseSize := size / numSegments
	remainder := size % numSegments

	// Distribute the remainder across segments.
	for i := range numSegments {
		segmentSizes[i] = baseSize
		if i < remainder {
			segmentSizes[i]++
		}
	}

	// Generate colors for each segment.
	for i := range numSegments {
		c1 := stopsPrime[i]
		c2 := stopsPrime[i+1]
		segmentSize := segmentSizes[i]

		for j := range segmentSize {
			var t float64
			if segmentSize > 1 {
				t = float64(j) / float64(segmentSize-1)
			}
			c := c1.BlendHcl(c2, t)
			blended = append(blended, c)
		}
	}

	return blended
}