fastapi-output 0.3.0

//! Theme system for fastapi_rust console output.
//!
//! Defines color palettes, icons, spacing, and box styles for consistent
//! visual output across all components. Colors follow the FastAPI
//! visual identity and Swagger UI conventions for familiarity.
//!
//! # Theme Presets
//!
//! - `FastApi` - Default theme inspired by FastAPI documentation
//! - `Neon` - High-contrast cyberpunk theme
//! - `Minimal` - Grayscale with subtle accents
//! - `Monokai` - Dark theme inspired by the Monokai color scheme
//! - `Light` - Optimized for light terminal backgrounds
//! - `Accessible` - High-contrast, WCAG-compliant colors
//!
//! # Components
//!
//! - [`FastApiTheme`] - Color palette for all UI elements
//! - [`ThemeIcons`] - Unicode icons with ASCII fallbacks
//! - [`ThemeSpacing`] - Consistent layout spacing values
//! - [`BoxStyle`] - Box drawing character sets
//!
//! # Example
//!
//! ```rust
//! use fastapi_output::themes::{FastApiTheme, ThemePreset, ThemeIcons, ThemeSpacing};
//!
//! // Get default theme
//! let theme = FastApiTheme::default();
//!
//! // Get theme by preset
//! let neon = FastApiTheme::from_preset(ThemePreset::Neon);
//!
//! // Use icons (with ASCII fallback)
//! let icons = ThemeIcons::unicode();
//! println!("{} Success!", icons.success);
//!
//! // Consistent spacing
//! let spacing = ThemeSpacing::default();
//! let indent = " ".repeat(spacing.indent);
//!
//! // Parse from environment variable
//! let preset: ThemePreset = "monokai".parse().unwrap();
//! ```

// Hex color literals (0xRRGGBB) are idiomatic and readable as-is
#![allow(clippy::unreadable_literal)]

use std::str::FromStr;

/// A color in RGB format.
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub struct Color {
    /// Red component (0-255).
    pub r: u8,
    /// Green component (0-255).
    pub g: u8,
    /// Blue component (0-255).
    pub b: u8,
}

impl Color {
    /// Create a new color from RGB values.
    #[must_use]
    pub const fn new(r: u8, g: u8, b: u8) -> Self {
        Self { r, g, b }
    }

    /// Create a color from a hex value (0xRRGGBB).
    #[must_use]
    pub const fn from_hex(hex: u32) -> Self {
        Self {
            r: ((hex >> 16) & 0xFF) as u8,
            g: ((hex >> 8) & 0xFF) as u8,
            b: (hex & 0xFF) as u8,
        }
    }

    /// Convert to hex string (e.g., "#009688").
    #[must_use]
    pub fn to_hex(&self) -> String {
        format!("#{:02x}{:02x}{:02x}", self.r, self.g, self.b)
    }

    /// Convert to RGB tuple.
    #[must_use]
    pub const fn to_rgb(&self) -> (u8, u8, u8) {
        (self.r, self.g, self.b)
    }

    /// Convert to ANSI 24-bit foreground escape code.
    #[must_use]
    pub fn to_ansi_fg(&self) -> String {
        format!("\x1b[38;2;{};{};{}m", self.r, self.g, self.b)
    }

    /// Convert to ANSI 24-bit background escape code.
    #[must_use]
    pub fn to_ansi_bg(&self) -> String {
        format!("\x1b[48;2;{};{};{}m", self.r, self.g, self.b)
    }

    /// Calculate relative luminance for contrast calculations.
    ///
    /// Uses the WCAG formula for relative luminance.
    #[must_use]
    pub fn luminance(&self) -> f64 {
        fn channel_luminance(c: u8) -> f64 {
            let c = f64::from(c) / 255.0;
            if c <= 0.03928 {
                c / 12.92
            } else {
                ((c + 0.055) / 1.055).powf(2.4)
            }
        }
        0.2126 * channel_luminance(self.r)
            + 0.7152 * channel_luminance(self.g)
            + 0.0722 * channel_luminance(self.b)
    }

    /// Calculate WCAG contrast ratio between this color and another.
    ///
    /// Returns a value between 1.0 (no contrast) and 21.0 (max contrast).
    /// WCAG AA requires 4.5:1 for normal text, 3:1 for large text.
    #[must_use]
    pub fn contrast_ratio(&self, other: &Color) -> f64 {
        let l1 = self.luminance();
        let l2 = other.luminance();
        let (lighter, darker) = if l1 > l2 { (l1, l2) } else { (l2, l1) };
        (lighter + 0.05) / (darker + 0.05)
    }
}

// ================================================================================================
// Theme Icons
// ================================================================================================

/// Icons used throughout the theme for visual feedback.
///
/// Provides both Unicode icons and ASCII fallbacks for terminals
/// that don't support extended Unicode characters.
///
/// # Example
///
/// ```rust
/// use fastapi_output::themes::ThemeIcons;
///
/// let icons = ThemeIcons::unicode();
/// println!("{} Success!", icons.success);
///
/// // For older terminals
/// let ascii = ThemeIcons::ascii();
/// println!("{} Success!", ascii.success);
/// ```
#[derive(Debug, Clone, PartialEq, Eq)]
pub struct ThemeIcons {
    /// Success indicator (e.g., checkmark).
    pub success: &'static str,
    /// Failure/error indicator (e.g., X).
    pub failure: &'static str,
    /// Warning indicator.
    pub warning: &'static str,
    /// Info indicator.
    pub info: &'static str,
    /// Right arrow for flow indication.
    pub arrow_right: &'static str,
    /// Left arrow.
    pub arrow_left: &'static str,
    /// Bullet point.
    pub bullet: &'static str,
    /// Lock/security indicator.
    pub lock: &'static str,
    /// Unlock indicator.
    pub unlock: &'static str,
    /// HTTP indicator.
    pub http: &'static str,
    /// Loading/in-progress indicator.
    pub loading: &'static str,
    /// Route/path indicator.
    pub route: &'static str,
    /// Database/storage indicator.
    pub database: &'static str,
    /// Time/clock indicator.
    pub time: &'static str,
    /// Size/memory indicator.
    pub size: &'static str,
}

impl ThemeIcons {
    /// Create icons using Unicode characters.
    ///
    /// Recommended for modern terminals with good Unicode support.
    #[must_use]
    pub const fn unicode() -> Self {
        Self {
            success: "\u{2713}",     // ✓
            failure: "\u{2717}",     // ✗
            warning: "\u{26A0}",     // ⚠
            info: "\u{2139}",        // ℹ
            arrow_right: "\u{2192}", // →
            arrow_left: "\u{2190}",  // ←
            bullet: "\u{2022}",      // •
            lock: "\u{1F512}",       // 🔒
            unlock: "\u{1F513}",     // 🔓
            http: "\u{1F310}",       // 🌐
            loading: "\u{25CF}",     // ●
            route: "\u{2192}",       // →
            database: "\u{1F5C4}",   // 🗄
            time: "\u{23F1}",        // ⏱
            size: "\u{1F4BE}",       // 💾
        }
    }

    /// Create icons using ASCII-only characters.
    ///
    /// Use for terminals without Unicode support or when
    /// consistent character widths are required.
    #[must_use]
    pub const fn ascii() -> Self {
        Self {
            success: "[OK]",
            failure: "[X]",
            warning: "[!]",
            info: "[i]",
            arrow_right: "->",
            arrow_left: "<-",
            bullet: "*",
            lock: "[#]",
            unlock: "[ ]",
            http: "[H]",
            loading: "...",
            route: "->",
            database: "[D]",
            time: "[T]",
            size: "[S]",
        }
    }

    /// Create compact Unicode icons (single-width preferred).
    ///
    /// Uses single-width Unicode where possible for better alignment.
    #[must_use]
    pub const fn compact() -> Self {
        Self {
            success: "\u{2713}", // ✓
            failure: "\u{2717}", // ✗
            warning: "!",
            info: "i",
            arrow_right: ">",
            arrow_left: "<",
            bullet: "\u{2022}", // •
            lock: "#",
            unlock: "o",
            http: "@",
            loading: ".",
            route: "/",
            database: "D",
            time: "T",
            size: "S",
        }
    }

    /// Auto-detect based on environment.
    ///
    /// Returns ASCII icons if TERM is "dumb" or if running in
    /// a known agent environment that prefers plain text.
    #[must_use]
    pub fn auto() -> Self {
        if std::env::var("TERM").is_ok_and(|t| t == "dumb")
            || std::env::var("CI").is_ok()
            || std::env::var("CLAUDE_CODE").is_ok()
            || std::env::var("CODEX_CLI").is_ok()
        {
            Self::ascii()
        } else {
            Self::unicode()
        }
    }
}

impl Default for ThemeIcons {
    fn default() -> Self {
        Self::unicode()
    }
}

// ================================================================================================
// Theme Spacing
// ================================================================================================

/// Spacing values for consistent layout across components.
///
/// All values are in character units for terminal output.
///
/// # Example
///
/// ```rust
/// use fastapi_output::themes::ThemeSpacing;
///
/// let spacing = ThemeSpacing::default();
/// let indent = " ".repeat(spacing.indent);
/// println!("{}Indented content", indent);
/// ```
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub struct ThemeSpacing {
    /// Standard indentation level (characters).
    pub indent: usize,
    /// Padding inside panels/boxes (characters).
    pub panel_padding: usize,
    /// Cell padding in tables (characters).
    pub table_cell_padding: usize,
    /// Gap between sections (blank lines).
    pub section_gap: usize,
    /// Gap between related items (blank lines).
    pub item_gap: usize,
    /// Width of method column in route tables.
    pub method_width: usize,
    /// Width of status code column.
    pub status_width: usize,
}

impl ThemeSpacing {
    /// Create default spacing suitable for most terminals.
    #[must_use]
    pub const fn default_spacing() -> Self {
        Self {
            indent: 2,
            panel_padding: 1,
            table_cell_padding: 1,
            section_gap: 1,
            item_gap: 0,
            method_width: 7, // "OPTIONS" is longest at 7 chars
            status_width: 3, // "500" is 3 chars
        }
    }

    /// Create compact spacing for dense output.
    #[must_use]
    pub const fn compact() -> Self {
        Self {
            indent: 1,
            panel_padding: 0,
            table_cell_padding: 1,
            section_gap: 0,
            item_gap: 0,
            method_width: 6,
            status_width: 3,
        }
    }

    /// Create spacious layout for readability.
    #[must_use]
    pub const fn spacious() -> Self {
        Self {
            indent: 4,
            panel_padding: 2,
            table_cell_padding: 2,
            section_gap: 2,
            item_gap: 1,
            method_width: 8,
            status_width: 4,
        }
    }
}

impl Default for ThemeSpacing {
    fn default() -> Self {
        Self::default_spacing()
    }
}

// ================================================================================================
// Box Styles
// ================================================================================================

/// Box drawing character sets for panels and tables.
///
/// Supports multiple styles from minimal ASCII to decorative Unicode.
///
/// # Example
///
/// ```rust
/// use fastapi_output::themes::BoxStyle;
///
/// let style = BoxStyle::rounded();
/// println!("{}{}{}", style.top_left, style.horizontal, style.top_right);
/// // ╭─╮
/// ```
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub struct BoxStyle {
    /// Top-left corner character.
    pub top_left: char,
    /// Top-right corner character.
    pub top_right: char,
    /// Bottom-left corner character.
    pub bottom_left: char,
    /// Bottom-right corner character.
    pub bottom_right: char,
    /// Horizontal line character.
    pub horizontal: char,
    /// Vertical line character.
    pub vertical: char,
    /// Left T-junction for tables.
    pub left_tee: char,
    /// Right T-junction for tables.
    pub right_tee: char,
    /// Top T-junction for tables.
    pub top_tee: char,
    /// Bottom T-junction for tables.
    pub bottom_tee: char,
    /// Cross/plus for table intersections.
    pub cross: char,
}

impl BoxStyle {
    /// Rounded corners using Unicode box drawing characters.
    #[must_use]
    pub const fn rounded() -> Self {
        Self {
            top_left: '\u{256D}',     // ╭
            top_right: '\u{256E}',    // ╮
            bottom_left: '\u{2570}',  // ╰
            bottom_right: '\u{256F}', // ╯
            horizontal: '\u{2500}',   // ─
            vertical: '\u{2502}',     // │
            left_tee: '\u{251C}',     // ├
            right_tee: '\u{2524}',    // ┤
            top_tee: '\u{252C}',      // ┬
            bottom_tee: '\u{2534}',   // ┴
            cross: '\u{253C}',        // ┼
        }
    }

    /// Square corners using Unicode box drawing characters.
    #[must_use]
    pub const fn square() -> Self {
        Self {
            top_left: '\u{250C}',     // ┌
            top_right: '\u{2510}',    // ┐
            bottom_left: '\u{2514}',  // └
            bottom_right: '\u{2518}', // ┘
            horizontal: '\u{2500}',   // ─
            vertical: '\u{2502}',     // │
            left_tee: '\u{251C}',     // ├
            right_tee: '\u{2524}',    // ┤
            top_tee: '\u{252C}',      // ┬
            bottom_tee: '\u{2534}',   // ┴
            cross: '\u{253C}',        // ┼
        }
    }

    /// Heavy/bold box drawing characters.
    #[must_use]
    pub const fn heavy() -> Self {
        Self {
            top_left: '\u{250F}',     // ┏
            top_right: '\u{2513}',    // ┓
            bottom_left: '\u{2517}',  // ┗
            bottom_right: '\u{251B}', // ┛
            horizontal: '\u{2501}',   // ━
            vertical: '\u{2503}',     // ┃
            left_tee: '\u{2523}',     // ┣
            right_tee: '\u{252B}',    // ┫
            top_tee: '\u{2533}',      // ┳
            bottom_tee: '\u{253B}',   // ┻
            cross: '\u{254B}',        // ╋
        }
    }

    /// Double-line box drawing characters.
    #[must_use]
    pub const fn double() -> Self {
        Self {
            top_left: '\u{2554}',     // ╔
            top_right: '\u{2557}',    // ╗
            bottom_left: '\u{255A}',  // ╚
            bottom_right: '\u{255D}', // ╝
            horizontal: '\u{2550}',   // ═
            vertical: '\u{2551}',     // ║
            left_tee: '\u{2560}',     // ╠
            right_tee: '\u{2563}',    // ╣
            top_tee: '\u{2566}',      // ╦
            bottom_tee: '\u{2569}',   // ╩
            cross: '\u{256C}',        // ╬
        }
    }

    /// ASCII-only box drawing using +, -, |.
    #[must_use]
    pub const fn ascii() -> Self {
        Self {
            top_left: '+',
            top_right: '+',
            bottom_left: '+',
            bottom_right: '+',
            horizontal: '-',
            vertical: '|',
            left_tee: '+',
            right_tee: '+',
            top_tee: '+',
            bottom_tee: '+',
            cross: '+',
        }
    }

    /// No visible borders (space characters).
    #[must_use]
    pub const fn none() -> Self {
        Self {
            top_left: ' ',
            top_right: ' ',
            bottom_left: ' ',
            bottom_right: ' ',
            horizontal: ' ',
            vertical: ' ',
            left_tee: ' ',
            right_tee: ' ',
            top_tee: ' ',
            bottom_tee: ' ',
            cross: ' ',
        }
    }

    /// Draw a horizontal line of the specified width.
    #[must_use]
    pub fn horizontal_line(&self, width: usize) -> String {
        std::iter::repeat_n(self.horizontal, width).collect()
    }

    /// Draw a complete top border with corners.
    #[must_use]
    pub fn top_border(&self, width: usize) -> String {
        format!(
            "{}{}{}",
            self.top_left,
            self.horizontal_line(width.saturating_sub(2)),
            self.top_right
        )
    }

    /// Draw a complete bottom border with corners.
    #[must_use]
    pub fn bottom_border(&self, width: usize) -> String {
        format!(
            "{}{}{}",
            self.bottom_left,
            self.horizontal_line(width.saturating_sub(2)),
            self.bottom_right
        )
    }
}

impl Default for BoxStyle {
    fn default() -> Self {
        Self::rounded()
    }
}

/// Preset for box style selection.
#[derive(Debug, Clone, Copy, PartialEq, Eq, Default)]
pub enum BoxStylePreset {
    /// Rounded corners (default).
    #[default]
    Rounded,
    /// Square corners.
    Square,
    /// Heavy/bold lines.
    Heavy,
    /// Double-line borders.
    Double,
    /// ASCII-only characters.
    Ascii,
    /// No visible borders.
    None,
}

impl BoxStylePreset {
    /// Get the `BoxStyle` for this preset.
    #[must_use]
    pub const fn style(&self) -> BoxStyle {
        match self {
            Self::Rounded => BoxStyle::rounded(),
            Self::Square => BoxStyle::square(),
            Self::Heavy => BoxStyle::heavy(),
            Self::Double => BoxStyle::double(),
            Self::Ascii => BoxStyle::ascii(),
            Self::None => BoxStyle::none(),
        }
    }
}

impl FromStr for BoxStylePreset {
    type Err = BoxStyleParseError;

    fn from_str(s: &str) -> Result<Self, Self::Err> {
        match s.to_lowercase().as_str() {
            "rounded" => Ok(Self::Rounded),
            "square" => Ok(Self::Square),
            "heavy" | "bold" => Ok(Self::Heavy),
            "double" => Ok(Self::Double),
            "ascii" | "plain" => Ok(Self::Ascii),
            "none" | "invisible" => Ok(Self::None),
            _ => Err(BoxStyleParseError(s.to_string())),
        }
    }
}

/// Error parsing box style name.
#[derive(Debug, Clone)]
pub struct BoxStyleParseError(String);

impl std::fmt::Display for BoxStyleParseError {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        write!(
            f,
            "unknown box style '{}', available: rounded, square, heavy, double, ascii, none",
            self.0
        )
    }
}

impl std::error::Error for BoxStyleParseError {}

/// Convert RGB tuple to hex string.
#[must_use]
pub fn rgb_to_hex(rgb: (u8, u8, u8)) -> String {
    format!("#{:02x}{:02x}{:02x}", rgb.0, rgb.1, rgb.2)
}

/// Parse hex color to RGB tuple.
///
/// Supports both 6-digit (#RRGGBB) and 3-digit (#RGB) formats.
/// The leading '#' is optional.
///
/// # Example
///
/// ```rust
/// use fastapi_output::themes::hex_to_rgb;
///
/// assert_eq!(hex_to_rgb("#009688"), Some((0, 150, 136)));
/// assert_eq!(hex_to_rgb("FF5500"), Some((255, 85, 0)));
/// assert_eq!(hex_to_rgb("#F00"), Some((255, 0, 0)));
/// ```
#[must_use]
pub fn hex_to_rgb(hex: &str) -> Option<(u8, u8, u8)> {
    let hex = hex.trim_start_matches('#');
    if hex.len() == 6 {
        let r = u8::from_str_radix(&hex[0..2], 16).ok()?;
        let g = u8::from_str_radix(&hex[2..4], 16).ok()?;
        let b = u8::from_str_radix(&hex[4..6], 16).ok()?;
        Some((r, g, b))
    } else if hex.len() == 3 {
        let r = u8::from_str_radix(&hex[0..1], 16).ok()? * 17;
        let g = u8::from_str_radix(&hex[1..2], 16).ok()? * 17;
        let b = u8::from_str_radix(&hex[2..3], 16).ok()? * 17;
        Some((r, g, b))
    } else {
        None
    }
}

/// FastAPI-inspired color theme for console output.
///
/// Contains colors for:
/// - Brand identity (primary, secondary, accent)
/// - Semantic meaning (success, warning, error, info)
/// - HTTP methods (GET, POST, PUT, DELETE, etc.)
/// - Status codes (1xx, 2xx, 3xx, 4xx, 5xx)
/// - Structural elements (border, header, muted, highlight)
#[derive(Debug, Clone, PartialEq, Eq)]
pub struct FastApiTheme {
    // === Brand Colors ===
    /// Primary brand color (teal, inspired by FastAPI docs).
    pub primary: Color,
    /// Secondary brand color.
    pub secondary: Color,
    /// Accent color for highlights.
    pub accent: Color,

    // === Semantic Colors ===
    /// Success indicator color (green).
    pub success: Color,
    /// Warning indicator color (orange/yellow).
    pub warning: Color,
    /// Error indicator color (red).
    pub error: Color,
    /// Info indicator color (blue).
    pub info: Color,

    // === HTTP Method Colors (Swagger UI conventions) ===
    /// GET method color (blue).
    pub http_get: Color,
    /// POST method color (green).
    pub http_post: Color,
    /// PUT method color (orange).
    pub http_put: Color,
    /// DELETE method color (red).
    pub http_delete: Color,
    /// PATCH method color (cyan).
    pub http_patch: Color,
    /// OPTIONS method color (gray).
    pub http_options: Color,
    /// HEAD method color (purple).
    pub http_head: Color,

    // === Status Code Colors ===
    /// 1xx informational (gray).
    pub status_1xx: Color,
    /// 2xx success (green).
    pub status_2xx: Color,
    /// 3xx redirect (cyan).
    pub status_3xx: Color,
    /// 4xx client error (yellow/orange).
    pub status_4xx: Color,
    /// 5xx server error (red).
    pub status_5xx: Color,

    // === Structural Colors ===
    /// Border color for boxes/panels.
    pub border: Color,
    /// Header text color.
    pub header: Color,
    /// Muted/secondary text color.
    pub muted: Color,
    /// Background highlight color.
    pub highlight_bg: Color,
}

impl FastApiTheme {
    /// Create a theme from a preset.
    #[must_use]
    pub fn from_preset(preset: ThemePreset) -> Self {
        match preset {
            ThemePreset::FastApi | ThemePreset::Default => Self::fastapi(),
            ThemePreset::Neon => Self::neon(),
            ThemePreset::Minimal => Self::minimal(),
            ThemePreset::Monokai => Self::monokai(),
            ThemePreset::Light => Self::light(),
            ThemePreset::Accessible => Self::accessible(),
        }
    }

    /// Create the default FastAPI-inspired theme.
    ///
    /// Colors chosen to match FastAPI documentation styling
    /// and Swagger UI conventions for familiarity.
    #[must_use]
    pub fn fastapi() -> Self {
        Self {
            // Brand colors (FastAPI teal/green)
            primary: Color::from_hex(0x009688),   // Teal 500
            secondary: Color::from_hex(0x4CAF50), // Green 500
            accent: Color::from_hex(0xFF9800),    // Orange 500

            // Semantic colors
            success: Color::from_hex(0x4CAF50), // Green
            warning: Color::from_hex(0xFF9800), // Orange
            error: Color::from_hex(0xF44336),   // Red
            info: Color::from_hex(0x2196F3),    // Blue

            // HTTP methods (Swagger UI)
            http_get: Color::from_hex(0x61AFFE),     // Blue
            http_post: Color::from_hex(0x49CC90),    // Green
            http_put: Color::from_hex(0xFCA130),     // Orange
            http_delete: Color::from_hex(0xF93E3E),  // Red
            http_patch: Color::from_hex(0x50E3C2),   // Cyan
            http_options: Color::from_hex(0x808080), // Gray
            http_head: Color::from_hex(0x9370DB),    // Purple

            // Status codes
            status_1xx: Color::from_hex(0x808080), // Gray
            status_2xx: Color::from_hex(0x4CAF50), // Green
            status_3xx: Color::from_hex(0x00BCD4), // Cyan
            status_4xx: Color::from_hex(0xFFC107), // Yellow/Amber
            status_5xx: Color::from_hex(0xF44336), // Red

            // Structural
            border: Color::from_hex(0x9E9E9E),       // Gray 500
            header: Color::from_hex(0x009688),       // Primary
            muted: Color::from_hex(0x757575),        // Gray 600
            highlight_bg: Color::from_hex(0x263238), // Blue Grey 900
        }
    }

    /// Create a neon/cyberpunk theme with high contrast.
    #[must_use]
    pub fn neon() -> Self {
        Self {
            primary: Color::from_hex(0x00FFFF),   // Cyan
            secondary: Color::from_hex(0xFF00FF), // Magenta
            accent: Color::from_hex(0xFFFF00),    // Yellow

            success: Color::from_hex(0x00FF80), // Neon green
            warning: Color::from_hex(0xFFFF00), // Yellow
            error: Color::from_hex(0xFF0040),   // Hot pink/red
            info: Color::from_hex(0x0080FF),    // Electric blue

            http_get: Color::from_hex(0x00FFFF),
            http_post: Color::from_hex(0x00FF80),
            http_put: Color::from_hex(0xFFA500),
            http_delete: Color::from_hex(0xFF0040),
            http_patch: Color::from_hex(0xFF00FF),
            http_options: Color::from_hex(0x808080),
            http_head: Color::from_hex(0x9400D3),

            status_1xx: Color::from_hex(0x808080),
            status_2xx: Color::from_hex(0x00FF80),
            status_3xx: Color::from_hex(0x00FFFF),
            status_4xx: Color::from_hex(0xFFFF00),
            status_5xx: Color::from_hex(0xFF0040),

            border: Color::from_hex(0x00FFFF),
            header: Color::from_hex(0xFF00FF),
            muted: Color::from_hex(0x646464),
            highlight_bg: Color::from_hex(0x141428),
        }
    }

    /// Create a minimal grayscale theme with accent colors.
    #[must_use]
    pub fn minimal() -> Self {
        Self {
            primary: Color::from_hex(0xC8C8C8),
            secondary: Color::from_hex(0xB4B4B4),
            accent: Color::from_hex(0xFF9800),

            success: Color::from_hex(0x64C864),
            warning: Color::from_hex(0xFFB400),
            error: Color::from_hex(0xFF6464),
            info: Color::from_hex(0x6496FF),

            http_get: Color::from_hex(0x9696C8),
            http_post: Color::from_hex(0x96C896),
            http_put: Color::from_hex(0xC8B464),
            http_delete: Color::from_hex(0xC86464),
            http_patch: Color::from_hex(0x64C8C8),
            http_options: Color::from_hex(0x808080),
            http_head: Color::from_hex(0xB496C8),

            status_1xx: Color::from_hex(0x808080),
            status_2xx: Color::from_hex(0x64C864),
            status_3xx: Color::from_hex(0x64C8C8),
            status_4xx: Color::from_hex(0xC8B464),
            status_5xx: Color::from_hex(0xC86464),

            border: Color::from_hex(0x646464),
            header: Color::from_hex(0xDCDCDC),
            muted: Color::from_hex(0x505050),
            highlight_bg: Color::from_hex(0x1E1E1E),
        }
    }

    /// Create a Monokai-inspired dark theme.
    #[must_use]
    pub fn monokai() -> Self {
        Self {
            primary: Color::from_hex(0xA6E22E),   // Monokai green
            secondary: Color::from_hex(0x66D9EF), // Monokai cyan
            accent: Color::from_hex(0xFD971F),    // Monokai orange

            success: Color::from_hex(0xA6E22E),
            warning: Color::from_hex(0xFD971F),
            error: Color::from_hex(0xF92672), // Monokai pink/red
            info: Color::from_hex(0x66D9EF),

            http_get: Color::from_hex(0x66D9EF),
            http_post: Color::from_hex(0xA6E22E),
            http_put: Color::from_hex(0xFD971F),
            http_delete: Color::from_hex(0xF92672),
            http_patch: Color::from_hex(0xAE81FF), // Monokai purple
            http_options: Color::from_hex(0x75715E),
            http_head: Color::from_hex(0xAE81FF),

            status_1xx: Color::from_hex(0x75715E),
            status_2xx: Color::from_hex(0xA6E22E),
            status_3xx: Color::from_hex(0x66D9EF),
            status_4xx: Color::from_hex(0xFD971F),
            status_5xx: Color::from_hex(0xF92672),

            border: Color::from_hex(0x75715E),
            header: Color::from_hex(0xF8F8F2),
            muted: Color::from_hex(0x75715E),
            highlight_bg: Color::from_hex(0x272822),
        }
    }

    /// Create a theme optimized for light terminal backgrounds.
    ///
    /// Uses darker, more saturated colors that maintain good contrast
    /// against white or light-colored terminal backgrounds.
    #[must_use]
    pub fn light() -> Self {
        Self {
            // Brand colors - darker for light backgrounds
            primary: Color::from_hex(0x00796B),   // Darker teal
            secondary: Color::from_hex(0x388E3C), // Darker green
            accent: Color::from_hex(0xE65100),    // Darker orange

            // Semantic colors - saturated for visibility
            success: Color::from_hex(0x2E7D32), // Dark green
            warning: Color::from_hex(0xE65100), // Dark orange
            error: Color::from_hex(0xC62828),   // Dark red
            info: Color::from_hex(0x1565C0),    // Dark blue

            // HTTP methods - darker versions of Swagger colors
            http_get: Color::from_hex(0x1976D2),    // Darker blue
            http_post: Color::from_hex(0x2E7D32),   // Dark green
            http_put: Color::from_hex(0xE65100),    // Dark orange
            http_delete: Color::from_hex(0xC62828), // Dark red
            http_patch: Color::from_hex(0x00838F),  // Dark cyan
            http_options: Color::from_hex(0x616161), // Medium gray
            http_head: Color::from_hex(0x6A1B9A),   // Dark purple

            // Status codes
            status_1xx: Color::from_hex(0x616161), // Gray
            status_2xx: Color::from_hex(0x2E7D32), // Dark green
            status_3xx: Color::from_hex(0x00838F), // Dark cyan
            status_4xx: Color::from_hex(0xE65100), // Dark orange
            status_5xx: Color::from_hex(0xC62828), // Dark red

            // Structural - dark for light backgrounds
            border: Color::from_hex(0x9E9E9E),       // Medium gray
            header: Color::from_hex(0x212121),       // Near black
            muted: Color::from_hex(0x757575),        // Medium gray
            highlight_bg: Color::from_hex(0xE3F2FD), // Very light blue
        }
    }

    /// Create a high-contrast accessible theme.
    ///
    /// Designed to meet WCAG 2.1 Level AA contrast requirements (4.5:1 minimum).
    /// Uses bright, saturated colors for maximum visibility.
    ///
    /// # Color Choices
    ///
    /// - All colors have >4.5:1 contrast ratio against dark backgrounds
    /// - Uses pure, saturated terminal colors for maximum compatibility
    /// - Semantic colors follow universal conventions (red=error, green=success)
    /// - Avoids colors that may be difficult for colorblind users
    #[must_use]
    pub fn accessible() -> Self {
        Self {
            // Brand colors - high contrast, saturated
            primary: Color::from_hex(0x00FFFF),   // Bright cyan
            secondary: Color::from_hex(0x00FF00), // Bright green
            accent: Color::from_hex(0xFFFF00),    // Bright yellow

            // Semantic colors - pure terminal colors
            success: Color::from_hex(0x00FF00), // Bright green
            warning: Color::from_hex(0xFFFF00), // Bright yellow
            error: Color::from_hex(0xFF0000),   // Bright red
            info: Color::from_hex(0x00FFFF),    // Bright cyan

            // HTTP methods - distinct, high-contrast colors
            http_get: Color::from_hex(0x00FFFF),     // Cyan
            http_post: Color::from_hex(0x00FF00),    // Green
            http_put: Color::from_hex(0xFFFF00),     // Yellow
            http_delete: Color::from_hex(0xFF0000),  // Red
            http_patch: Color::from_hex(0xFF00FF),   // Magenta
            http_options: Color::from_hex(0xFFFFFF), // White
            http_head: Color::from_hex(0xFF00FF),    // Magenta

            // Status codes - clear semantic mapping
            status_1xx: Color::from_hex(0xFFFFFF), // White
            status_2xx: Color::from_hex(0x00FF00), // Green
            status_3xx: Color::from_hex(0x00FFFF), // Cyan
            status_4xx: Color::from_hex(0xFFFF00), // Yellow
            status_5xx: Color::from_hex(0xFF0000), // Red

            // Structural - maximum contrast
            border: Color::from_hex(0xFFFFFF),       // White
            header: Color::from_hex(0xFFFFFF),       // White
            muted: Color::from_hex(0xC0C0C0),        // Silver/light gray
            highlight_bg: Color::from_hex(0x000080), // Navy blue
        }
    }

    // === Color Lookup Methods ===

    /// Get the color for an HTTP method.
    ///
    /// # Example
    ///
    /// ```rust
    /// use fastapi_output::themes::FastApiTheme;
    ///
    /// let theme = FastApiTheme::default();
    /// let get_color = theme.http_method_color("GET");
    /// let post_color = theme.http_method_color("post"); // case-insensitive
    /// ```
    #[must_use]
    pub fn http_method_color(&self, method: &str) -> Color {
        match method.to_uppercase().as_str() {
            "GET" => self.http_get,
            "POST" => self.http_post,
            "PUT" => self.http_put,
            "DELETE" => self.http_delete,
            "PATCH" => self.http_patch,
            "OPTIONS" => self.http_options,
            "HEAD" => self.http_head,
            _ => self.muted,
        }
    }

    /// Get the color for an HTTP status code.
    ///
    /// # Example
    ///
    /// ```rust
    /// use fastapi_output::themes::FastApiTheme;
    ///
    /// let theme = FastApiTheme::default();
    /// let success_color = theme.status_code_color(200);
    /// let error_color = theme.status_code_color(500);
    /// ```
    #[must_use]
    pub fn status_code_color(&self, code: u16) -> Color {
        match code {
            100..=199 => self.status_1xx,
            200..=299 => self.status_2xx,
            300..=399 => self.status_3xx,
            400..=499 => self.status_4xx,
            500..=599 => self.status_5xx,
            _ => self.muted,
        }
    }

    // === Hex String Helpers ===

    /// Get primary color as hex string.
    #[must_use]
    pub fn primary_hex(&self) -> String {
        self.primary.to_hex()
    }

    /// Get success color as hex string.
    #[must_use]
    pub fn success_hex(&self) -> String {
        self.success.to_hex()
    }

    /// Get error color as hex string.
    #[must_use]
    pub fn error_hex(&self) -> String {
        self.error.to_hex()
    }

    /// Get warning color as hex string.
    #[must_use]
    pub fn warning_hex(&self) -> String {
        self.warning.to_hex()
    }

    /// Get info color as hex string.
    #[must_use]
    pub fn info_hex(&self) -> String {
        self.info.to_hex()
    }

    /// Get accent color as hex string.
    #[must_use]
    pub fn accent_hex(&self) -> String {
        self.accent.to_hex()
    }

    /// Get color for HTTP method as hex string.
    #[must_use]
    pub fn http_method_hex(&self, method: &str) -> String {
        self.http_method_color(method).to_hex()
    }

    /// Get color for status code as hex string.
    #[must_use]
    pub fn status_code_hex(&self, code: u16) -> String {
        self.status_code_color(code).to_hex()
    }
}

impl Default for FastApiTheme {
    fn default() -> Self {
        Self::fastapi()
    }
}

/// Predefined theme presets.
///
/// Select a theme by name or environment variable.
#[derive(Debug, Clone, Copy, PartialEq, Eq, Default)]
pub enum ThemePreset {
    /// Default FastAPI-inspired theme.
    #[default]
    Default,
    /// Alias for Default - FastAPI-inspired theme.
    FastApi,
    /// Neon/cyberpunk high contrast theme.
    Neon,
    /// Minimal grayscale with accents.
    Minimal,
    /// Monokai dark theme.
    Monokai,
    /// Theme optimized for light terminal backgrounds.
    Light,
    /// High-contrast, WCAG-compliant accessible theme.
    Accessible,
}

impl ThemePreset {
    /// Get the `FastApiTheme` for this preset.
    #[must_use]
    pub fn theme(&self) -> FastApiTheme {
        FastApiTheme::from_preset(*self)
    }

    /// List all available preset names.
    #[must_use]
    pub fn available_presets() -> &'static [&'static str] {
        &[
            "default",
            "fastapi",
            "neon",
            "minimal",
            "monokai",
            "light",
            "accessible",
        ]
    }
}

impl std::fmt::Display for ThemePreset {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        match self {
            Self::Default => write!(f, "default"),
            Self::FastApi => write!(f, "fastapi"),
            Self::Neon => write!(f, "neon"),
            Self::Minimal => write!(f, "minimal"),
            Self::Monokai => write!(f, "monokai"),
            Self::Light => write!(f, "light"),
            Self::Accessible => write!(f, "accessible"),
        }
    }
}

impl FromStr for ThemePreset {
    type Err = ThemePresetParseError;

    fn from_str(s: &str) -> Result<Self, Self::Err> {
        match s.to_lowercase().as_str() {
            "default" | "fastapi" => Ok(Self::FastApi),
            "neon" | "cyberpunk" => Ok(Self::Neon),
            "minimal" | "gray" | "grey" => Ok(Self::Minimal),
            "monokai" | "dark" => Ok(Self::Monokai),
            "light" => Ok(Self::Light),
            "accessible" | "a11y" => Ok(Self::Accessible),
            _ => Err(ThemePresetParseError(s.to_string())),
        }
    }
}

/// Error parsing theme preset name.
#[derive(Debug, Clone)]
pub struct ThemePresetParseError(String);

impl ThemePresetParseError {
    /// Get the invalid preset name that was provided.
    #[must_use]
    pub fn invalid_name(&self) -> &str {
        &self.0
    }
}

impl std::fmt::Display for ThemePresetParseError {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        write!(
            f,
            "unknown theme preset '{}', available: {}",
            self.0,
            ThemePreset::available_presets().join(", ")
        )
    }
}

impl std::error::Error for ThemePresetParseError {}

#[cfg(test)]
mod tests {
    use super::*;

    fn is_not_black(c: Color) -> bool {
        c.r > 0 || c.g > 0 || c.b > 0
    }

    // === Color Tests ===

    #[test]
    fn test_color_from_hex() {
        let color = Color::from_hex(0xFF5500);
        assert_eq!(color.r, 0xFF);
        assert_eq!(color.g, 0x55);
        assert_eq!(color.b, 0x00);
    }

    #[test]
    fn test_color_to_hex() {
        let color = Color::new(255, 85, 0);
        assert_eq!(color.to_hex(), "#ff5500");
    }

    #[test]
    fn test_color_to_rgb() {
        let color = Color::new(100, 150, 200);
        assert_eq!(color.to_rgb(), (100, 150, 200));
    }

    #[test]
    fn test_color_to_ansi() {
        let color = Color::new(255, 128, 64);
        assert_eq!(color.to_ansi_fg(), "\x1b[38;2;255;128;64m");
        assert_eq!(color.to_ansi_bg(), "\x1b[48;2;255;128;64m");
    }

    // === Conversion Utility Tests ===

    #[test]
    fn test_rgb_to_hex() {
        assert_eq!(rgb_to_hex((0, 150, 136)), "#009688");
        assert_eq!(rgb_to_hex((255, 255, 255)), "#ffffff");
        assert_eq!(rgb_to_hex((0, 0, 0)), "#000000");
    }

    #[test]
    fn test_hex_to_rgb_6_digit() {
        assert_eq!(hex_to_rgb("#009688"), Some((0, 150, 136)));
        assert_eq!(hex_to_rgb("009688"), Some((0, 150, 136)));
        assert_eq!(hex_to_rgb("#FF5500"), Some((255, 85, 0)));
        assert_eq!(hex_to_rgb("#ffffff"), Some((255, 255, 255)));
    }

    #[test]
    fn test_hex_to_rgb_3_digit() {
        assert_eq!(hex_to_rgb("#F00"), Some((255, 0, 0)));
        assert_eq!(hex_to_rgb("0F0"), Some((0, 255, 0)));
        assert_eq!(hex_to_rgb("#FFF"), Some((255, 255, 255)));
    }

    #[test]
    fn test_hex_to_rgb_invalid() {
        assert_eq!(hex_to_rgb("invalid"), None);
        assert_eq!(hex_to_rgb("#12345"), None);
        assert_eq!(hex_to_rgb(""), None);
        assert_eq!(hex_to_rgb("#GGG"), None);
    }

    // === Theme Tests ===

    #[test]
    fn test_theme_default_has_all_colors() {
        let theme = FastApiTheme::default();

        // Brand colors
        assert!(is_not_black(theme.primary));
        assert!(is_not_black(theme.secondary));
        assert!(is_not_black(theme.accent));

        // Semantic colors
        assert!(is_not_black(theme.success));
        assert!(is_not_black(theme.warning));
        assert!(is_not_black(theme.error));
        assert!(is_not_black(theme.info));

        // HTTP method colors
        assert!(is_not_black(theme.http_get));
        assert!(is_not_black(theme.http_post));
        assert!(is_not_black(theme.http_put));
        assert!(is_not_black(theme.http_delete));
    }

    #[test]
    fn test_theme_presets_differ() {
        let fastapi = FastApiTheme::fastapi();
        let neon = FastApiTheme::neon();
        let minimal = FastApiTheme::minimal();
        let monokai = FastApiTheme::monokai();
        let light = FastApiTheme::light();
        let accessible = FastApiTheme::accessible();

        assert_ne!(fastapi, neon);
        assert_ne!(fastapi, minimal);
        assert_ne!(fastapi, monokai);
        assert_ne!(fastapi, light);
        assert_ne!(fastapi, accessible);
        assert_ne!(neon, minimal);
        assert_ne!(neon, monokai);
        assert_ne!(neon, light);
        assert_ne!(neon, accessible);
        assert_ne!(minimal, monokai);
        assert_ne!(minimal, light);
        assert_ne!(minimal, accessible);
        assert_ne!(monokai, light);
        assert_ne!(monokai, accessible);
        assert_ne!(light, accessible);
    }

    #[test]
    fn test_theme_from_preset() {
        assert_eq!(
            FastApiTheme::from_preset(ThemePreset::Default),
            FastApiTheme::fastapi()
        );
        assert_eq!(
            FastApiTheme::from_preset(ThemePreset::FastApi),
            FastApiTheme::fastapi()
        );
        assert_eq!(
            FastApiTheme::from_preset(ThemePreset::Neon),
            FastApiTheme::neon()
        );
        assert_eq!(
            FastApiTheme::from_preset(ThemePreset::Minimal),
            FastApiTheme::minimal()
        );
        assert_eq!(
            FastApiTheme::from_preset(ThemePreset::Monokai),
            FastApiTheme::monokai()
        );
        assert_eq!(
            FastApiTheme::from_preset(ThemePreset::Light),
            FastApiTheme::light()
        );
        assert_eq!(
            FastApiTheme::from_preset(ThemePreset::Accessible),
            FastApiTheme::accessible()
        );
    }

    // === HTTP Method Color Tests ===

    #[test]
    fn test_http_method_colors() {
        let theme = FastApiTheme::default();

        assert_eq!(theme.http_method_color("GET"), theme.http_get);
        assert_eq!(theme.http_method_color("get"), theme.http_get);
        assert_eq!(theme.http_method_color("POST"), theme.http_post);
        assert_eq!(theme.http_method_color("PUT"), theme.http_put);
        assert_eq!(theme.http_method_color("DELETE"), theme.http_delete);
        assert_eq!(theme.http_method_color("PATCH"), theme.http_patch);
        assert_eq!(theme.http_method_color("OPTIONS"), theme.http_options);
        assert_eq!(theme.http_method_color("HEAD"), theme.http_head);
        assert_eq!(theme.http_method_color("UNKNOWN"), theme.muted);
    }

    #[test]
    fn test_http_method_hex() {
        let theme = FastApiTheme::default();
        assert_eq!(theme.http_method_hex("GET"), theme.http_get.to_hex());
        assert_eq!(theme.http_method_hex("POST"), theme.http_post.to_hex());
    }

    // === Status Code Color Tests ===

    #[test]
    fn test_status_code_colors() {
        let theme = FastApiTheme::default();

        assert_eq!(theme.status_code_color(100), theme.status_1xx);
        assert_eq!(theme.status_code_color(199), theme.status_1xx);
        assert_eq!(theme.status_code_color(200), theme.status_2xx);
        assert_eq!(theme.status_code_color(201), theme.status_2xx);
        assert_eq!(theme.status_code_color(301), theme.status_3xx);
        assert_eq!(theme.status_code_color(404), theme.status_4xx);
        assert_eq!(theme.status_code_color(500), theme.status_5xx);
        assert_eq!(theme.status_code_color(503), theme.status_5xx);
        assert_eq!(theme.status_code_color(600), theme.muted);
        assert_eq!(theme.status_code_color(99), theme.muted);
    }

    #[test]
    fn test_status_code_hex() {
        let theme = FastApiTheme::default();
        assert_eq!(theme.status_code_hex(200), theme.status_2xx.to_hex());
        assert_eq!(theme.status_code_hex(500), theme.status_5xx.to_hex());
    }

    // === Hex Helper Tests ===

    #[test]
    fn test_hex_helpers() {
        let theme = FastApiTheme::default();

        assert_eq!(theme.primary_hex(), theme.primary.to_hex());
        assert_eq!(theme.success_hex(), theme.success.to_hex());
        assert_eq!(theme.error_hex(), theme.error.to_hex());
        assert_eq!(theme.warning_hex(), theme.warning.to_hex());
        assert_eq!(theme.info_hex(), theme.info.to_hex());
        assert_eq!(theme.accent_hex(), theme.accent.to_hex());
    }

    // === ThemePreset Tests ===

    #[test]
    fn test_theme_preset_display() {
        assert_eq!(ThemePreset::Default.to_string(), "default");
        assert_eq!(ThemePreset::FastApi.to_string(), "fastapi");
        assert_eq!(ThemePreset::Neon.to_string(), "neon");
        assert_eq!(ThemePreset::Minimal.to_string(), "minimal");
        assert_eq!(ThemePreset::Monokai.to_string(), "monokai");
        assert_eq!(ThemePreset::Light.to_string(), "light");
        assert_eq!(ThemePreset::Accessible.to_string(), "accessible");
    }

    #[test]
    fn test_theme_preset_from_str() {
        assert_eq!(
            "default".parse::<ThemePreset>().unwrap(),
            ThemePreset::FastApi
        );
        assert_eq!(
            "fastapi".parse::<ThemePreset>().unwrap(),
            ThemePreset::FastApi
        );
        assert_eq!(
            "FASTAPI".parse::<ThemePreset>().unwrap(),
            ThemePreset::FastApi
        );
        assert_eq!("neon".parse::<ThemePreset>().unwrap(), ThemePreset::Neon);
        assert_eq!(
            "cyberpunk".parse::<ThemePreset>().unwrap(),
            ThemePreset::Neon
        );
        assert_eq!(
            "minimal".parse::<ThemePreset>().unwrap(),
            ThemePreset::Minimal
        );
        assert_eq!("gray".parse::<ThemePreset>().unwrap(), ThemePreset::Minimal);
        assert_eq!("grey".parse::<ThemePreset>().unwrap(), ThemePreset::Minimal);
        assert_eq!(
            "monokai".parse::<ThemePreset>().unwrap(),
            ThemePreset::Monokai
        );
        assert_eq!("dark".parse::<ThemePreset>().unwrap(), ThemePreset::Monokai);
        assert_eq!("light".parse::<ThemePreset>().unwrap(), ThemePreset::Light);
        assert_eq!(
            "accessible".parse::<ThemePreset>().unwrap(),
            ThemePreset::Accessible
        );
        assert_eq!(
            "a11y".parse::<ThemePreset>().unwrap(),
            ThemePreset::Accessible
        );
    }

    #[test]
    fn test_theme_preset_from_str_invalid() {
        let err = "invalid".parse::<ThemePreset>().unwrap_err();
        assert_eq!(err.invalid_name(), "invalid");
        assert!(err.to_string().contains("invalid"));
        assert!(err.to_string().contains("available"));
    }

    #[test]
    fn test_theme_preset_theme() {
        assert_eq!(ThemePreset::FastApi.theme(), FastApiTheme::fastapi());
        assert_eq!(ThemePreset::Neon.theme(), FastApiTheme::neon());
        assert_eq!(ThemePreset::Light.theme(), FastApiTheme::light());
        assert_eq!(ThemePreset::Accessible.theme(), FastApiTheme::accessible());
    }

    #[test]
    fn test_available_presets() {
        let presets = ThemePreset::available_presets();
        assert!(presets.contains(&"default"));
        assert!(presets.contains(&"fastapi"));
        assert!(presets.contains(&"neon"));
        assert!(presets.contains(&"minimal"));
        assert!(presets.contains(&"monokai"));
        assert!(presets.contains(&"light"));
        assert!(presets.contains(&"accessible"));
    }

    // === ThemeIcons Tests ===

    #[test]
    fn test_theme_icons_unicode() {
        let icons = ThemeIcons::unicode();
        assert!(!icons.success.is_empty());
        assert!(!icons.failure.is_empty());
        assert!(!icons.warning.is_empty());
        assert!(!icons.info.is_empty());
    }

    #[test]
    fn test_theme_icons_ascii() {
        let icons = ThemeIcons::ascii();
        assert!(icons.success.is_ascii());
        assert!(icons.failure.is_ascii());
        assert!(icons.warning.is_ascii());
        assert!(icons.info.is_ascii());
    }

    #[test]
    fn test_theme_icons_compact() {
        let icons = ThemeIcons::compact();
        assert!(!icons.success.is_empty());
        assert!(!icons.arrow_right.is_empty());
    }

    // === ThemeSpacing Tests ===

    #[test]
    fn test_theme_spacing_default() {
        let spacing = ThemeSpacing::default();
        assert!(spacing.indent > 0);
        assert!(spacing.method_width >= 7); // "OPTIONS" is 7 chars
    }

    #[test]
    fn test_theme_spacing_compact() {
        let compact = ThemeSpacing::compact();
        let default = ThemeSpacing::default();
        assert!(compact.indent <= default.indent);
    }

    #[test]
    fn test_theme_spacing_spacious() {
        let spacious = ThemeSpacing::spacious();
        let default = ThemeSpacing::default();
        assert!(spacious.indent >= default.indent);
    }

    // === BoxStyle Tests ===

    #[test]
    fn test_box_style_rounded() {
        let style = BoxStyle::rounded();
        assert_ne!(style.top_left, style.horizontal);
        assert_ne!(style.vertical, style.horizontal);
    }

    #[test]
    fn test_box_style_ascii() {
        let style = BoxStyle::ascii();
        assert_eq!(style.top_left, '+');
        assert_eq!(style.horizontal, '-');
        assert_eq!(style.vertical, '|');
    }

    #[test]
    fn test_box_style_horizontal_line() {
        let style = BoxStyle::rounded();
        let line = style.horizontal_line(5);
        assert_eq!(line.chars().count(), 5);
    }

    #[test]
    fn test_box_style_borders() {
        let style = BoxStyle::rounded();
        let top = style.top_border(10);
        let bottom = style.bottom_border(10);
        assert!(top.starts_with(style.top_left));
        assert!(top.ends_with(style.top_right));
        assert!(bottom.starts_with(style.bottom_left));
        assert!(bottom.ends_with(style.bottom_right));
    }

    #[test]
    fn test_box_style_preset_parse() {
        assert_eq!(
            "rounded".parse::<BoxStylePreset>().unwrap(),
            BoxStylePreset::Rounded
        );
        assert_eq!(
            "heavy".parse::<BoxStylePreset>().unwrap(),
            BoxStylePreset::Heavy
        );
        assert_eq!(
            "ascii".parse::<BoxStylePreset>().unwrap(),
            BoxStylePreset::Ascii
        );
        assert!("invalid".parse::<BoxStylePreset>().is_err());
    }

    // === Color Contrast Tests ===

    #[test]
    fn test_color_luminance() {
        let black = Color::new(0, 0, 0);
        let white = Color::new(255, 255, 255);
        assert!(black.luminance() < 0.01);
        assert!(white.luminance() > 0.99);
    }

    #[test]
    fn test_color_contrast_ratio() {
        let black = Color::new(0, 0, 0);
        let white = Color::new(255, 255, 255);
        let ratio = black.contrast_ratio(&white);
        // Max contrast is 21:1
        assert!(ratio > 20.0);
        assert!(ratio <= 21.0);
    }

    #[test]
    fn test_accessible_theme_high_contrast() {
        let accessible = FastApiTheme::accessible();
        let black = Color::new(0, 0, 0);

        // All semantic colors should have good contrast against black background
        assert!(accessible.success.contrast_ratio(&black) >= 4.5);
        assert!(accessible.error.contrast_ratio(&black) >= 4.5);
        assert!(accessible.warning.contrast_ratio(&black) >= 4.5);
        assert!(accessible.info.contrast_ratio(&black) >= 4.5);
    }
}