use crate::render::{Color, LineStyle};

/// Comprehensive theme system for consistent plot styling
///
/// Themes control the visual appearance of all plot elements including colors,
/// fonts, spacing, and other visual properties.
///
/// # Available Themes
///
/// | Theme | Description |
/// |-------|-------------|
/// | [`Theme::light()`] | Default light theme with white background |
/// | [`Theme::dark()`] | Dark mode with dark background |
/// | [`Theme::seaborn()`] | Seaborn-inspired styling |
/// | [`Theme::publication()`] | Publication-ready, high contrast |
///
/// # Example
///
/// ```rust,no_run
/// use ruviz::prelude::*;
///
/// let x: Vec<f64> = (0..100).map(|i| i as f64 * 0.1).collect();
/// let y: Vec<f64> = x.iter().map(|&v| v.sin()).collect();
///
/// // Using dark theme
/// Plot::new()
///     .theme(Theme::dark())
///     .line(&x, &y)
///     .end_series()
///     .save("dark_plot.png")?;
/// # Ok::<(), Box<dyn std::error::Error>>(())
/// ```
///
/// # Visual Comparison
///
/// | Default | Dark | Seaborn | Publication |
/// |---------|------|---------|-------------|
/// | ![Default](https://raw.githubusercontent.com/Ameyanagi/ruviz/main/docs/images/theme_default.png) | ![Dark](https://raw.githubusercontent.com/Ameyanagi/ruviz/main/docs/images/theme_dark.png) | ![Seaborn](https://raw.githubusercontent.com/Ameyanagi/ruviz/main/docs/images/theme_seaborn.png) | ![Publication](https://raw.githubusercontent.com/Ameyanagi/ruviz/main/docs/images/theme_publication.png) |
#[derive(Debug, Clone)]
pub struct Theme {
    /// Background color of the plot area
    pub background: Color,
    /// Foreground color for text and axes
    pub foreground: Color,
    /// Grid line color
    pub grid_color: Color,
    /// Default line width for plot elements (in points, 1pt = 1/72 inch)
    pub line_width: f32,
    /// Default line style
    pub line_style: LineStyle,
    /// Primary font family name
    pub font_family: String,
    /// Default font size for labels and text (in points)
    pub font_size: f32,
    /// Title font size (in points)
    pub title_font_size: f32,
    /// Legend font size (in points)
    pub legend_font_size: f32,
    /// Axis label font size (in points)
    pub axis_label_font_size: f32,
    /// Tick label font size (in points)
    pub tick_label_font_size: f32,
    /// Default color palette for automatic color cycling
    pub color_palette: Vec<Color>,
    /// Margin around the plot (as fraction of canvas size)
    pub margin: f32,
    /// Padding between plot elements (in points)
    pub padding: f32,
    /// Use colorblind-friendly palette
    pub colorblind_friendly: bool,
}

impl Theme {
    /// Create a new theme builder
    ///
    /// # Example
    ///
    /// ```rust,no_run
    /// use ruviz::prelude::*;
    ///
    /// let custom_theme = Theme::builder()
    ///     .background(Color::from_hex("#1a1a2e").unwrap())
    ///     .foreground(Color::WHITE)
    ///     .font_size(12.0)
    ///     .build();
    /// ```
    pub fn builder() -> ThemeBuilder {
        ThemeBuilder::default()
    }

    /// Create default light theme
    ///
    /// White background with black text, suitable for documents and light mode interfaces.
    ///
    /// # Example
    ///
    /// ```rust,no_run
    /// use ruviz::prelude::*;
    ///
    /// Plot::new()
    ///     .theme(Theme::light())
    ///     .line(&[1.0, 2.0, 3.0], &[1.0, 4.0, 9.0])
    ///     .end_series()
    ///     .save("light_plot.png")?;
    /// # Ok::<(), Box<dyn std::error::Error>>(())
    /// ```
    pub fn light() -> Self {
        Self {
            background: Color::WHITE,
            foreground: Color::BLACK,
            grid_color: Color::LIGHT_GRAY,
            line_width: 1.5, // matplotlib default: 1.5pt
            line_style: LineStyle::Solid,
            font_family: "sans-serif".to_string(),
            font_size: 10.0,            // matplotlib default: 10pt
            title_font_size: 14.0,      // 1.4x base
            legend_font_size: 9.0,      // 0.9x base
            axis_label_font_size: 10.0, // 1.0x base
            tick_label_font_size: 9.0,  // 0.9x base
            color_palette: Color::default_palette().to_vec(),
            margin: 0.1,
            padding: 8.0,
            colorblind_friendly: false,
        }
    }

    /// Create dark theme
    ///
    /// Dark background with light text, ideal for dark mode interfaces and reducing eye strain.
    ///
    /// # Example
    ///
    /// ```rust,no_run
    /// use ruviz::prelude::*;
    ///
    /// Plot::new()
    ///     .theme(Theme::dark())
    ///     .line(&[1.0, 2.0, 3.0], &[1.0, 4.0, 9.0])
    ///     .end_series()
    ///     .save("dark_plot.png")?;
    /// # Ok::<(), Box<dyn std::error::Error>>(())
    /// ```
    pub fn dark() -> Self {
        Self {
            background: Color::from_hex("#1e1e1e").unwrap(),
            foreground: Color::WHITE,
            grid_color: Color::DARK_GRAY,
            line_width: 1.5, // matplotlib default: 1.5pt
            line_style: LineStyle::Solid,
            font_family: "sans-serif".to_string(),
            font_size: 10.0,            // matplotlib default: 10pt
            title_font_size: 14.0,      // 1.4x base
            legend_font_size: 9.0,      // 0.9x base
            axis_label_font_size: 10.0, // 1.0x base
            tick_label_font_size: 9.0,  // 0.9x base
            color_palette: Self::dark_palette(),
            margin: 0.1,
            padding: 8.0,
            colorblind_friendly: false,
        }
    }

    /// Create publication-ready theme (high contrast, clean)
    ///
    /// Uses serif fonts and grayscale colors suitable for academic journals and print.
    ///
    /// # Example
    ///
    /// ```rust,no_run
    /// use ruviz::prelude::*;
    ///
    /// Plot::new()
    ///     .theme(Theme::publication())
    ///     .line(&[1.0, 2.0, 3.0], &[1.0, 4.0, 9.0])
    ///     .end_series()
    ///     .save("publication_plot.png")?;
    /// # Ok::<(), Box<dyn std::error::Error>>(())
    /// ```
    pub fn publication() -> Self {
        Self {
            background: Color::WHITE,
            foreground: Color::BLACK,
            grid_color: Color::from_hex("#E0E0E0").unwrap(),
            line_width: 1.5,
            line_style: LineStyle::Solid,
            font_family: "Times New Roman".to_string(),
            font_size: 10.0,
            title_font_size: 12.0,
            legend_font_size: 9.0,
            axis_label_font_size: 10.0,
            tick_label_font_size: 8.0,
            color_palette: Self::publication_palette(),
            margin: 0.08,
            padding: 6.0,
            colorblind_friendly: false,
        }
    }

    /// Create minimal theme (minimal visual elements)
    pub fn minimal() -> Self {
        Self {
            background: Color::WHITE,
            foreground: Color::BLACK,
            grid_color: Color::TRANSPARENT,
            line_width: 1.5,
            line_style: LineStyle::Solid,
            font_family: "Helvetica".to_string(),
            font_size: 11.0,
            title_font_size: 14.0,
            legend_font_size: 10.0,
            axis_label_font_size: 11.0,
            tick_label_font_size: 9.0,
            color_palette: Self::minimal_palette(),
            margin: 0.05,
            padding: 4.0,
            colorblind_friendly: false,
        }
    }

    /// Create colorblind-friendly theme
    pub fn colorblind_friendly() -> Self {
        let mut theme = Self::light();
        theme.color_palette = Self::colorblind_palette();
        theme.colorblind_friendly = true;
        theme
    }

    /// Create seaborn-style theme (matplotlib-inspired, clean and professional)
    ///
    /// Inspired by Python's seaborn library, with a clean, modern aesthetic.
    ///
    /// # Example
    ///
    /// ```rust,no_run
    /// use ruviz::prelude::*;
    ///
    /// Plot::new()
    ///     .theme(Theme::seaborn())
    ///     .line(&[1.0, 2.0, 3.0], &[1.0, 4.0, 9.0])
    ///     .end_series()
    ///     .save("seaborn_plot.png")?;
    /// # Ok::<(), Box<dyn std::error::Error>>(())
    /// ```
    pub fn seaborn() -> Self {
        Self {
            background: Color::WHITE,
            foreground: Color::from_hex("#262626").unwrap(), // Dark gray instead of pure black
            grid_color: Color::from_hex("#F0F0F0").unwrap(), // Light gray grid
            line_width: 1.5,
            line_style: LineStyle::Solid,
            font_family: "DejaVu Sans".to_string(), // Seaborn's preferred font
            font_size: 11.0,
            title_font_size: 14.0,
            legend_font_size: 10.0,
            axis_label_font_size: 11.0,
            tick_label_font_size: 9.0,
            color_palette: Self::seaborn_palette(),
            margin: 0.08,
            padding: 8.0,
            colorblind_friendly: false,
        }
    }

    /// Create IEEE publication-ready theme
    /// Optimized for IEEE journal column constraints and professional typography
    pub fn ieee() -> Self {
        Self {
            background: Color::WHITE,
            foreground: Color::BLACK,
            grid_color: Color::from_hex("#E5E5E5").unwrap(), // Subtle grid for print
            line_width: 0.75,                                // Match PlotStyle::IEEE data_width
            line_style: LineStyle::Solid,
            font_family: "serif".to_string(), // IEEE standard serif font
            font_size: 8.0,                   // Small size for column constraints
            title_font_size: 9.0,             // IEEE title sizing (1.125x base)
            legend_font_size: 6.0,            // Compact legend (0.75x base)
            axis_label_font_size: 8.0,        // 1.0x base
            tick_label_font_size: 7.0,        // 0.875x base
            color_palette: Self::wong_palette(), // Accessibility-first colorblind friendly
            margin: 0.12,                     // IEEE standard margins
            padding: 6.0,
            colorblind_friendly: true,
        }
    }

    /// Create Nature/Science journal theme
    /// Follows Nature journal style guidelines for multi-panel figures
    pub fn nature() -> Self {
        Self {
            background: Color::WHITE,
            foreground: Color::BLACK,
            grid_color: Color::TRANSPARENT, // Nature style: no grid
            line_width: 0.75,               // Match PlotStyle::Nature data_width
            line_style: LineStyle::Solid,
            font_family: "sans-serif".to_string(), // Nature standard sans-serif
            font_size: 7.0,                        // Small for multi-panel figures
            title_font_size: 8.05,                 // 1.15x base
            legend_font_size: 5.95,                // 0.85x base
            axis_label_font_size: 7.0,             // 1.0x base
            tick_label_font_size: 5.95,            // 0.85x base
            color_palette: Self::scientific_palette(), // Scientific standard colors
            margin: 0.08,                          // Tight margins for space efficiency
            padding: 4.0,
            colorblind_friendly: false,
        }
    }

    /// Create presentation theme for slides and projectors
    /// High contrast and large fonts for visibility from distance
    pub fn presentation() -> Self {
        Self {
            background: Color::WHITE,
            foreground: Color::BLACK,
            grid_color: Color::from_hex("#CCCCCC").unwrap(), // Visible but not dominant grid
            line_width: 2.5, // Thick lines for visibility (same as PlotStyle::Presentation)
            line_style: LineStyle::Solid,
            font_family: "sans-serif".to_string(), // High legibility sans-serif
            font_size: 14.0, // Large for distance viewing (same as PlotStyle::Presentation)
            title_font_size: 19.6, // 1.4x base
            legend_font_size: 11.9, // 0.85x base
            axis_label_font_size: 14.0, // 1.0x base
            tick_label_font_size: 11.9, // 0.85x base
            color_palette: Self::presentation_palette(), // High contrast colors
            margin: 0.15,    // Extra spacing for clean look
            padding: 12.0,
            colorblind_friendly: false,
        }
    }

    /// Create Paul Tol's accessibility theme
    /// Uses Paul Tol's scientifically-tested color schemes
    pub fn paul_tol() -> Self {
        Self {
            background: Color::WHITE,
            foreground: Color::BLACK,
            grid_color: Color::from_hex("#E0E0E0").unwrap(),
            line_width: 1.5,
            line_style: LineStyle::Solid,
            font_family: "Arial".to_string(),
            font_size: 11.0,
            title_font_size: 14.0,
            legend_font_size: 10.0,
            axis_label_font_size: 11.0,
            tick_label_font_size: 9.0,
            color_palette: Self::paul_tol_palette(),
            margin: 0.1,
            padding: 8.0,
            colorblind_friendly: true,
        }
    }

    /// Get a color from the theme's palette by index (cycles if needed)
    pub fn get_color(&self, index: usize) -> Color {
        if self.color_palette.is_empty() {
            Color::BLACK
        } else {
            self.color_palette[index % self.color_palette.len()]
        }
    }

    /// Get the effective grid color (returns transparent if grid should be hidden)
    pub fn effective_grid_color(&self) -> Color {
        self.grid_color
    }

    // Color palettes for different themes

    fn dark_palette() -> Vec<Color> {
        vec![
            Color::from_hex("#8dd3c7").unwrap(), // Light cyan
            Color::from_hex("#ffffb3").unwrap(), // Light yellow
            Color::from_hex("#bebada").unwrap(), // Light purple
            Color::from_hex("#fb8072").unwrap(), // Light red
            Color::from_hex("#80b1d3").unwrap(), // Light blue
            Color::from_hex("#fdb462").unwrap(), // Light orange
            Color::from_hex("#b3de69").unwrap(), // Light green
            Color::from_hex("#fccde5").unwrap(), // Light pink
        ]
    }

    fn publication_palette() -> Vec<Color> {
        vec![
            Color::BLACK,
            Color::DARK_GRAY,
            Color::from_hex("#404040").unwrap(),
            Color::from_hex("#606060").unwrap(),
            Color::from_hex("#808080").unwrap(),
            Color::from_hex("#A0A0A0").unwrap(),
        ]
    }

    fn minimal_palette() -> Vec<Color> {
        vec![
            Color::BLACK,
            Color::from_hex("#666666").unwrap(),
            Color::from_hex("#999999").unwrap(),
            Color::from_hex("#CCCCCC").unwrap(),
        ]
    }

    fn colorblind_palette() -> Vec<Color> {
        // Optimized for deuteranopia/protanopia (most common color blindness)
        vec![
            Color::from_hex("#1f77b4").unwrap(), // Blue
            Color::from_hex("#ff7f0e").unwrap(), // Orange
            Color::from_hex("#2ca02c").unwrap(), // Green
            Color::from_hex("#d62728").unwrap(), // Red
            Color::from_hex("#9467bd").unwrap(), // Purple
            Color::from_hex("#8c564b").unwrap(), // Brown
            Color::from_hex("#e377c2").unwrap(), // Pink
            Color::from_hex("#bcbd22").unwrap(), // Olive
            Color::from_hex("#17becf").unwrap(), // Cyan
        ]
    }

    /// Wong palette (Bang Wong's accessibility-tested colorblind-friendly palette)
    /// Reference: https://davidmathlogic.com/colorblind/
    fn wong_palette() -> Vec<Color> {
        vec![
            Color::from_hex("#000000").unwrap(), // Black
            Color::from_hex("#E69F00").unwrap(), // Orange
            Color::from_hex("#56B4E9").unwrap(), // Sky blue
            Color::from_hex("#009E73").unwrap(), // Bluish green
            Color::from_hex("#F0E442").unwrap(), // Yellow
            Color::from_hex("#0072B2").unwrap(), // Blue
            Color::from_hex("#D55E00").unwrap(), // Vermillion
            Color::from_hex("#CC79A7").unwrap(), // Reddish purple
        ]
    }

    /// Paul Tol's high-contrast palette
    /// Reference: https://personal.sron.nl/~pault/
    fn paul_tol_palette() -> Vec<Color> {
        vec![
            Color::from_hex("#004488").unwrap(), // Dark blue
            Color::from_hex("#DDAA33").unwrap(), // Gold
            Color::from_hex("#BB5566").unwrap(), // Rose
            Color::from_hex("#000000").unwrap(), // Black
            Color::from_hex("#999933").unwrap(), // Olive
            Color::from_hex("#DDDDDD").unwrap(), // Light gray
            Color::from_hex("#EE8866").unwrap(), // Orange
            Color::from_hex("#77AADD").unwrap(), // Light blue
        ]
    }

    /// Scientific palette (matplotlib v2+ accessibility tested)
    fn scientific_palette() -> Vec<Color> {
        vec![
            Color::from_hex("#1f77b4").unwrap(), // Blue
            Color::from_hex("#ff7f0e").unwrap(), // Orange
            Color::from_hex("#2ca02c").unwrap(), // Green
            Color::from_hex("#d62728").unwrap(), // Red
            Color::from_hex("#9467bd").unwrap(), // Purple
            Color::from_hex("#8c564b").unwrap(), // Brown
            Color::from_hex("#e377c2").unwrap(), // Pink
            Color::from_hex("#7f7f7f").unwrap(), // Gray
            Color::from_hex("#bcbd22").unwrap(), // Olive
            Color::from_hex("#17becf").unwrap(), // Cyan
        ]
    }

    /// High-contrast palette for presentations
    fn presentation_palette() -> Vec<Color> {
        vec![
            Color::from_hex("#1f77b4").unwrap(), // Blue
            Color::from_hex("#ff7f0e").unwrap(), // Orange
            Color::from_hex("#2ca02c").unwrap(), // Green
            Color::from_hex("#d62728").unwrap(), // Red
            Color::from_hex("#9467bd").unwrap(), // Purple
            Color::from_hex("#000000").unwrap(), // Black
        ]
    }

    fn seaborn_palette() -> Vec<Color> {
        // Seaborn's default color palette (muted colors, professional)
        vec![
            Color::from_hex("#1f77b4").unwrap(), // Muted blue
            Color::from_hex("#ff7f0e").unwrap(), // Muted orange
            Color::from_hex("#2ca02c").unwrap(), // Muted green
            Color::from_hex("#d62728").unwrap(), // Muted red
            Color::from_hex("#9467bd").unwrap(), // Muted purple
            Color::from_hex("#8c564b").unwrap(), // Muted brown
            Color::from_hex("#e377c2").unwrap(), // Muted pink
            Color::from_hex("#7f7f7f").unwrap(), // Muted gray
            Color::from_hex("#bcbd22").unwrap(), // Muted olive
            Color::from_hex("#17becf").unwrap(), // Muted cyan
        ]
    }

    /// Convert theme typography settings to a TypographyConfig
    ///
    /// This allows Theme to be used with the new PlotConfig system.
    /// All font sizes in Theme are in points.
    ///
    /// # Example
    ///
    /// ```rust,ignore
    /// let theme = Theme::presentation();
    /// let typography = theme.to_typography_config();
    /// ```
    pub fn to_typography_config(&self) -> crate::core::config::TypographyConfig {
        use super::FontFamily;
        use crate::core::config::TypographyConfig;

        // Determine FontFamily from font_family string
        let family = match self.font_family.to_lowercase().as_str() {
            s if s.contains("serif") && !s.contains("sans") => FontFamily::Serif,
            s if s.contains("mono") || s.contains("courier") || s.contains("consolas") => {
                FontFamily::Monospace
            }
            _ => FontFamily::SansSerif,
        };

        TypographyConfig {
            base_size: self.font_size,
            title_scale: self.title_font_size / self.font_size,
            label_scale: self.axis_label_font_size / self.font_size,
            tick_scale: self.tick_label_font_size / self.font_size,
            legend_scale: self.legend_font_size / self.font_size,
            family,
            title_weight: super::FontWeight::Normal,
        }
    }

    /// Convert theme line settings to a LineConfig
    ///
    /// This allows Theme to be used with the new PlotConfig system.
    /// Line widths in Theme are in points.
    pub fn to_line_config(&self) -> crate::core::config::LineConfig {
        use crate::core::config::LineConfig;

        LineConfig {
            data_width: self.line_width,
            axis_width: self.line_width * 0.5,
            grid_width: self.line_width * 0.3,
            tick_width: self.line_width * 0.4,
            tick_length: 4.0, // Standard tick length
        }
    }
}

impl Default for Theme {
    /// Default theme is the light theme
    fn default() -> Self {
        Self::light()
    }
}

/// Builder pattern for creating custom themes
#[derive(Debug, Clone)]
pub struct ThemeBuilder {
    theme: Theme,
}

impl ThemeBuilder {
    /// Set background color
    pub fn background(mut self, color: Color) -> Self {
        self.theme.background = color;
        self
    }

    /// Set foreground color
    pub fn foreground(mut self, color: Color) -> Self {
        self.theme.foreground = color;
        self
    }

    /// Set grid color
    pub fn grid_color(mut self, color: Color) -> Self {
        self.theme.grid_color = color;
        self
    }

    /// Set default line width
    pub fn line_width(mut self, width: f32) -> Self {
        self.theme.line_width = width.max(0.1);
        self
    }

    /// Set default line style
    pub fn line_style(mut self, style: LineStyle) -> Self {
        self.theme.line_style = style;
        self
    }

    /// Set font family
    pub fn font<S: Into<String>>(mut self, font_family: S) -> Self {
        self.theme.font_family = font_family.into();
        self
    }

    /// Set default font size
    pub fn font_size(mut self, size: f32) -> Self {
        self.theme.font_size = size.max(6.0);
        self
    }

    /// Set title font size
    pub fn title_font_size(mut self, size: f32) -> Self {
        self.theme.title_font_size = size.max(6.0);
        self
    }

    /// Set legend font size
    pub fn legend_font_size(mut self, size: f32) -> Self {
        self.theme.legend_font_size = size.max(6.0);
        self
    }

    /// Set color palette
    pub fn palette<I>(mut self, colors: I) -> Self
    where
        I: IntoIterator<Item = Color>,
    {
        self.theme.color_palette = colors.into_iter().collect();
        self
    }

    /// Enable colorblind-friendly palette
    pub fn colorblind_palette(mut self, enabled: bool) -> Self {
        self.theme.colorblind_friendly = enabled;
        if enabled {
            self.theme.color_palette = Theme::colorblind_palette();
        }
        self
    }

    /// Set margin
    pub fn margin(mut self, margin: f32) -> Self {
        self.theme.margin = margin.clamp(0.0, 0.5);
        self
    }

    /// Set padding
    pub fn padding(mut self, padding: f32) -> Self {
        self.theme.padding = padding.max(0.0);
        self
    }

    /// Build the theme
    pub fn build(self) -> Theme {
        self.theme
    }
}

#[allow(clippy::derivable_impls)] // Theme::light() is the semantic default, not Theme::default()
impl Default for ThemeBuilder {
    fn default() -> Self {
        Self {
            theme: Theme::light(),
        }
    }
}

/// Predefined theme variants
#[allow(clippy::upper_case_acronyms)] // IEEE is the standard organization acronym
pub enum ThemeVariant {
    Light,
    Dark,
    Publication,
    Minimal,
    ColorblindFriendly,
    Seaborn,
    IEEE,
    Nature,
    Presentation,
    PaulTol,
}

impl ThemeVariant {
    /// Convert theme variant to actual theme
    pub fn to_theme(&self) -> Theme {
        match self {
            ThemeVariant::Light => Theme::light(),
            ThemeVariant::Dark => Theme::dark(),
            ThemeVariant::Publication => Theme::publication(),
            ThemeVariant::Minimal => Theme::minimal(),
            ThemeVariant::ColorblindFriendly => Theme::colorblind_friendly(),
            ThemeVariant::Seaborn => Theme::seaborn(),
            ThemeVariant::IEEE => Theme::ieee(),
            ThemeVariant::Nature => Theme::nature(),
            ThemeVariant::Presentation => Theme::presentation(),
            ThemeVariant::PaulTol => Theme::paul_tol(),
        }
    }
}

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

    #[test]
    fn test_default_theme() {
        let theme = Theme::default();
        assert_eq!(theme.background, Color::WHITE);
        assert_eq!(theme.foreground, Color::BLACK);
        assert!(theme.font_size > 0.0);
        assert!(!theme.color_palette.is_empty());
    }

    #[test]
    fn test_theme_variants() {
        let light = Theme::light();
        let dark = Theme::dark();
        let publication = Theme::publication();
        let minimal = Theme::minimal();
        let colorblind = Theme::colorblind_friendly();

        assert_eq!(light.background, Color::WHITE);
        assert_eq!(dark.background, Color::from_hex("#1e1e1e").unwrap());
        assert_eq!(publication.font_family, "Times New Roman");
        assert_eq!(minimal.font_family, "Helvetica");
        assert!(colorblind.colorblind_friendly);
    }

    #[test]
    fn test_scientific_themes() {
        let ieee = Theme::ieee();
        let nature = Theme::nature();
        let presentation = Theme::presentation();
        let paul_tol = Theme::paul_tol();

        // IEEE theme tests - uses serif font, 8pt base, 0.75pt lines
        assert_eq!(ieee.font_family, "serif");
        assert_eq!(ieee.font_size, 8.0);
        assert!(ieee.colorblind_friendly);
        assert!((ieee.line_width - 0.75).abs() < 0.01);

        // Nature theme tests - uses sans-serif, 7pt base, no grid
        assert_eq!(nature.font_family, "sans-serif");
        assert_eq!(nature.font_size, 7.0);
        assert_eq!(nature.grid_color, Color::TRANSPARENT);

        // Presentation theme tests - 14pt base, 2.5pt lines
        assert_eq!(presentation.font_size, 14.0);
        assert!((presentation.line_width - 2.5).abs() < 0.01);
        assert!((presentation.title_font_size - 19.6).abs() < 0.01);

        // Paul Tol theme tests
        assert!(paul_tol.colorblind_friendly);
        assert_eq!(paul_tol.color_palette.len(), 8);
    }

    #[test]
    fn test_scientific_color_palettes() {
        let wong = Theme::wong_palette();
        let paul_tol = Theme::paul_tol_palette();
        let scientific = Theme::scientific_palette();
        let presentation = Theme::presentation_palette();

        // Wong palette should have 8 colors
        assert_eq!(wong.len(), 8);
        assert_eq!(wong[0], Color::from_hex("#000000").unwrap()); // Black

        // Paul Tol palette should have 8 colors
        assert_eq!(paul_tol.len(), 8);
        assert_eq!(paul_tol[0], Color::from_hex("#004488").unwrap()); // Dark blue

        // Scientific palette should have 10 colors
        assert_eq!(scientific.len(), 10);

        // Presentation palette should have 6 high-contrast colors
        assert_eq!(presentation.len(), 6);
    }

    #[test]
    fn test_theme_builder() {
        let theme = Theme::builder()
            .background(Color::BLUE)
            .foreground(Color::WHITE)
            .font("Helvetica")
            .font_size(14.0)
            .line_width(3.0)
            .margin(0.05)
            .colorblind_palette(true)
            .build();

        assert_eq!(theme.background, Color::BLUE);
        assert_eq!(theme.foreground, Color::WHITE);
        assert_eq!(theme.font_family, "Helvetica");
        assert_eq!(theme.font_size, 14.0);
        assert_eq!(theme.line_width, 3.0);
        assert_eq!(theme.margin, 0.05);
        assert!(theme.colorblind_friendly);
    }

    #[test]
    fn test_color_cycling() {
        let theme = Theme::light();
        let color0 = theme.get_color(0);
        let color1 = theme.get_color(1);
        let color_cycle = theme.get_color(theme.color_palette.len());

        assert_eq!(color0, color_cycle); // Should cycle back to first color
        assert_ne!(color0, color1); // Different colors
    }

    #[test]
    fn test_builder_validation() {
        let theme = Theme::builder()
            .font_size(-5.0) // Invalid, should be clamped
            .line_width(-1.0) // Invalid, should be clamped
            .margin(-0.1) // Invalid, should be clamped
            .build();

        assert!(theme.font_size >= 6.0); // Minimum font size
        assert!(theme.line_width >= 0.1); // Minimum line width
        assert!(theme.margin >= 0.0); // Minimum margin
    }

    #[test]
    fn test_theme_variant_conversion() {
        let light = ThemeVariant::Light.to_theme();
        let dark = ThemeVariant::Dark.to_theme();
        let ieee = ThemeVariant::IEEE.to_theme();
        let nature = ThemeVariant::Nature.to_theme();
        let presentation = ThemeVariant::Presentation.to_theme();
        let paul_tol = ThemeVariant::PaulTol.to_theme();

        assert_eq!(light.background, Color::WHITE);
        assert_ne!(dark.background, Color::WHITE);

        // Test scientific theme variants
        assert_eq!(ieee.font_family, "serif");
        assert_eq!(nature.grid_color, Color::TRANSPARENT);
        assert_eq!(presentation.font_size, 14.0);
        assert!(paul_tol.colorblind_friendly);
    }

    #[test]
    fn test_empty_palette() {
        let mut theme = Theme::light();
        theme.color_palette.clear();

        // Should return black for empty palette
        assert_eq!(theme.get_color(0), Color::BLACK);
        assert_eq!(theme.get_color(5), Color::BLACK);
    }
}
