package style

import (
	"strings"

	"git.gophernest.net/azpect/TextEditor/internal/core"
	"github.com/alecthomas/chroma/v2"
	"github.com/alecthomas/chroma/v2/lexers"
	"github.com/charmbracelet/lipgloss"
)

// Styles holds all the visual styling for the editor.
type Styles struct {
	// Cursor styles by mode
	CursorNormal  lipgloss.Style
	CursorInsert  lipgloss.Style
	CursorCommand lipgloss.Style
	CursorReplace lipgloss.Style

	// Gutter (line numbers)
	Gutter            lipgloss.Style
	GutterCurrentLine lipgloss.Style

	// Visual mode
	VisualHighlight lipgloss.Style
	VisualAnchor    lipgloss.Style // debugging

	// Status bar
	StatusBar       lipgloss.Style
	StatusBarActive lipgloss.Style

	// Command line
	CommandError           lipgloss.Style
	CommandOutputBorder    lipgloss.Style
	CommandContinueMessage lipgloss.Style

	// General Styles
	LineStyle       lipgloss.Style // This is a simple background with no text coloring
	BackgroundStyle lipgloss.Style // This is just the background

	// Chroma data
	ChromaStyle *chroma.Style
}

// DefaultStyles: Returns the default editor color scheme.
func DefaultStyles() Styles {
	return Styles{
		CursorNormal:  lipgloss.NewStyle().Reverse(true),
		CursorInsert:  lipgloss.NewStyle().Underline(true),
		CursorCommand: lipgloss.NewStyle().Reverse(true),
		CursorReplace: lipgloss.NewStyle().Underline(true),

		Gutter: lipgloss.NewStyle().
			Background(lipgloss.Color("236")).
			Foreground(lipgloss.Color("243")),

		GutterCurrentLine: lipgloss.NewStyle().
			Background(lipgloss.Color("236")).
			Foreground(lipgloss.Color("#d69d00")),

		VisualHighlight: lipgloss.NewStyle().
			Background(lipgloss.Color("#7a6a00")),

		VisualAnchor: lipgloss.NewStyle().
			Background(lipgloss.Color("#a89020")),

		StatusBar: lipgloss.NewStyle().
			Background(lipgloss.Color("236")).
			Foreground(lipgloss.Color("243")),

		StatusBarActive: lipgloss.NewStyle().
			Background(lipgloss.Color("62")).
			Foreground(lipgloss.Color("230")),

		CommandError: lipgloss.NewStyle().
			Foreground(lipgloss.Color("#e3203a")),

		CommandOutputBorder: lipgloss.NewStyle().
			Background(lipgloss.Color("#000000")),

		CommandContinueMessage: lipgloss.NewStyle().
			Foreground(lipgloss.Color("#546fba")),

		ChromaStyle: nil,
	}
}

func ChromaStyles(chromaStyle *chroma.Style) Styles {
	bgString := chromaStyle.Get(chroma.Background).Background.String()
	lineNumbers := chromaStyle.Get(chroma.LineTableTD)
	lineHighlight := chromaStyle.Get(chroma.LineHighlight)

	return Styles{
		CursorNormal: lipgloss.NewStyle().
			Background(lipgloss.Color(bgString)).
			Reverse(true),

		CursorInsert: lipgloss.NewStyle().
			Background(lipgloss.Color(bgString)).
			Bold(true).
			Underline(true),

		CursorCommand: lipgloss.NewStyle().
			Background(lipgloss.Color(bgString)).
			Reverse(true),

		CursorReplace: lipgloss.NewStyle().
			Background(lipgloss.Color(bgString)).
			Underline(true),

		Gutter: lipgloss.NewStyle().
			Background(lipgloss.Color(
				darkenColor(lineNumbers.Background, 0.9).String()),
			).
			Foreground(lipgloss.Color(lineNumbers.Colour.String())),

		GutterCurrentLine: lipgloss.NewStyle().
			Background(lipgloss.Color(
				darkenColor(lineNumbers.Background, 0.9).String()),
			).
			Foreground(lipgloss.Color(lineNumbers.Colour.String())),

		VisualHighlight: lipgloss.NewStyle().
			Background(lipgloss.Color(lineHighlight.Background.String())).
			Foreground(lipgloss.Color(lineHighlight.Colour.String())),

		VisualAnchor: lipgloss.NewStyle().
			Background(lipgloss.Color(lineHighlight.Background.String())).
			Foreground(lipgloss.Color(lineHighlight.Colour.String())),

		StatusBar: lipgloss.NewStyle().
			Background(lipgloss.Color(bgString)).
			Foreground(lipgloss.Color("243")),

		StatusBarActive: lipgloss.NewStyle().
			Background(lipgloss.Color(bgString)).
			Foreground(lipgloss.Color("230")),

		CommandError: lipgloss.NewStyle().
			Background(lipgloss.Color(bgString)).
			Foreground(lipgloss.Color("#e3203a")),

		CommandOutputBorder: lipgloss.NewStyle().
			Background(
				lipgloss.Color(
					darkenColor(
						chromaStyle.Get(chroma.Background).Background, 0.5).
						String(),
				),
			),

		CommandContinueMessage: lipgloss.NewStyle().
			Background(lipgloss.Color(bgString)).
			Foreground(lipgloss.Color("#546fba")),

		LineStyle: lipgloss.NewStyle().
			Foreground(lipgloss.Color(chromaStyle.Get(chroma.Line).Colour.String())).
			Background(lipgloss.Color(bgString)),

		BackgroundStyle: lipgloss.NewStyle().Background(lipgloss.Color(bgString)),

		ChromaStyle: chromaStyle,
	}
}

// Styles.DefaultCursorStyle: Returns the appropriate cursor style for the given mode.
func (s Styles) DefaultCursorStyle(mode core.Mode) lipgloss.Style {
	switch mode {
	case core.InsertMode:
		return s.CursorInsert
	case core.CommandMode:
		return s.CursorCommand
	case core.ReplaceMode:
		return s.CursorReplace
	default:
		return s.CursorNormal
	}
}

// Styles.CursorStyle: Returns a cursor style derived from a chroma style. This function should preferred
// over the DefaultCursorStyle, but in cases where there is no style to apply, the DefaultCursorStyle
// will always work.
func (s Styles) CursorStyle(mode core.Mode, style lipgloss.Style) lipgloss.Style {
	switch mode {
	case core.NormalMode, core.VisualLineMode, core.VisualBlockMode, core.VisualMode:
		return lipgloss.NewStyle().
			Background(style.GetForeground()).
			Foreground(style.GetBackground())
	case core.ReplaceMode, core.WaitingMode:
		return lipgloss.NewStyle().
			Background(style.GetBackground()).
			Foreground(style.GetForeground()).
			Underline(true)
	default:
		return lipgloss.NewStyle().
			Background(s.BackgroundStyle.GetBackground()).
			Foreground(style.GetForeground()).
			Underline(true)
	}
}

// Styles.VisualHighlightWithTextColor: Works analogously to CursorStyle vs DefaultCursorStyle. When a
// style is available, this function should be used, so the text color will be rendered in front
// of the background. Otherwise, the VisualHighlight property will always work.
func (s Styles) VisualHighlightWithTextColor(style lipgloss.Style) lipgloss.Style {
	return lipgloss.NewStyle().
		Background(s.VisualHighlight.GetBackground()).
		Foreground(style.GetForeground())
}

// Styles.MakeStyleMap: Generates a style map for a single line. A style map is a mapping from
// column a lipgloss style. Cursor styles are not handled by this map, but they can be derived
// by inverting the background and foreground (and rolling back to the default).
func (s Styles) MakeStyleMap(lexer chroma.Lexer, line string) []lipgloss.Style {
	m := make([]lipgloss.Style, len(line))

	if s.ChromaStyle == nil {
		return m
	}

	iter, err := lexer.Tokenise(nil, line)
	if err != nil {
		panic(err)
	}

	col := 0
	for _, token := range iter.Tokens() {
		entry := s.ChromaStyle.Get(token.Type)
		s := lipgloss.NewStyle().
			Background(lipgloss.Color(entry.Background.String())).
			Foreground(lipgloss.Color(entry.Colour.String()))
		for _, char := range token.Value {
			if char == '\n' {
				continue
			}
			if col < len(m) {
				m[col] = s
			}
			col++
		}
	}

	return m
}

// darkenColor: Uses a factor (0.0 to 1.0) to darken a color using its opacity.
func darkenColor(c chroma.Colour, factor float64) chroma.Colour {
	r := uint8(float64(c.Red()) * factor)
	g := uint8(float64(c.Green()) * factor)
	b := uint8(float64(c.Blue()) * factor)
	return chroma.NewColour(r, g, b)
}

// GetLexer: Uses buffer meta data or content to pick a lexer for use in applying
// highlights.
func GetLexer(buf *core.Buffer) chroma.Lexer {
	var lexer chroma.Lexer

	if buf.Filetype != "" {
		lexer = lexers.Get(strings.TrimPrefix(buf.Filetype, "."))
	}

	if lexer == nil && buf.Filename != "" {
		lexer = lexers.Match(buf.Filename)
	}

	if lexer == nil && len(buf.Lines) > 0 {
		// Get first few lines for content analysis
		var content strings.Builder
		for i := 0; i < min(len(buf.Lines), 10); i++ {
			content.WriteString(buf.Lines[i].String() + "\n")
		}
		lexer = lexers.Analyse(content.String())
	}

	if lexer == nil {
		lexer = lexers.Fallback
	}

	lexer = chroma.Coalesce(lexer) // Merge tokens together
	return lexer
}