antifacet 0.1.0

//! Color generation utilities for pretty-printing

use core::hash::{
	Hash,
	Hasher,
};
type DefaultHasher = siphasher::sip::SipHasher;

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

impl RGB {
	/// Create a new RGB color
	pub fn new(
		r: u8,
		g: u8,
		b: u8,
	) -> Self {
		Self { r, g, b }
	}

	/// Write the RGB color as ANSI foreground color code to the formatter
	pub fn write_fg<W: core::fmt::Write>(
		&self,
		f: &mut W,
	) -> core::fmt::Result {
		write!(f, "\x1b[38;2;{};{};{}m", self.r, self.g, self.b)
	}

	/// Write the RGB color as ANSI background color code to the formatter
	pub fn write_bg<W: core::fmt::Write>(
		&self,
		f: &mut W,
	) -> core::fmt::Result {
		write!(f, "\x1b[48;2;{};{};{}m", self.r, self.g, self.b)
	}
}

/// A color generator that produces unique colors based on a hash value
pub struct ColorGenerator {
	base_hue: f32,
	saturation: f32,
	lightness: f32,
}

impl Default for ColorGenerator {
	fn default() -> Self {
		Self {
			base_hue: 210.0,
			saturation: 0.7,
			lightness: 0.6,
		}
	}
}

impl ColorGenerator {
	/// Create a new color generator with default settings
	pub fn new() -> Self {
		Self::default()
	}

	/// Set the base hue (0-360)
	pub fn with_base_hue(
		mut self,
		hue: f32,
	) -> Self {
		self.base_hue = hue;
		self
	}

	/// Set the saturation (0.0-1.0)
	pub fn with_saturation(
		mut self,
		saturation: f32,
	) -> Self {
		self.saturation = saturation.clamp(0.0, 1.0);
		self
	}

	/// Set the lightness (0.0-1.0)
	pub fn with_lightness(
		mut self,
		lightness: f32,
	) -> Self {
		self.lightness = lightness.clamp(0.0, 1.0);
		self
	}

	/// Generate an RGB color based on a hash value
	pub fn generate_color(
		&self,
		hash: u64,
	) -> RGB {
		// Use the hash to generate a hue offset
		let hue_offset = (hash % 360) as f32;
		let hue = (self.base_hue + hue_offset) % 360.0;

		// Convert HSL to RGB
		self.hsl_to_rgb(hue, self.saturation, self.lightness)
	}

	/// Generate an RGB color based on a hashable value
	pub fn generate_color_for<T: Hash>(
		&self,
		value: &T,
	) -> RGB {
		let mut hasher = DefaultHasher::new();
		value.hash(&mut hasher);
		let hash = hasher.finish();
		self.generate_color(hash)
	}

	/// Convert HSL color values to RGB
	fn hsl_to_rgb(
		&self,
		h: f32,
		s: f32,
		l: f32,
	) -> RGB {
		let c = (1.0 - (2.0 * l - 1.0).abs()) * s;
		let x = c * (1.0 - ((h / 60.0) % 2.0 - 1.0).abs());
		let m = l - c / 2.0;

		let (r, g, b) = match h as u32 {
			0..=59 => (c, x, 0.0),
			60..=119 => (x, c, 0.0),
			120..=179 => (0.0, c, x),
			180..=239 => (0.0, x, c),
			240..=299 => (x, 0.0, c),
			_ => (c, 0.0, x),
		};

		RGB::new(
			((r + m) * 255.0) as u8,
			((g + m) * 255.0) as u8,
			((b + m) * 255.0) as u8,
		)
	}
}

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

	#[test]
	fn test_color_generator_default() {
		let generator = ColorGenerator::default();
		assert_eq!(generator.base_hue, 210.0);
		assert_eq!(generator.saturation, 0.7);
		assert_eq!(generator.lightness, 0.6);
	}

	#[test]
	fn test_color_generator_with_methods() {
		let generator = ColorGenerator::new()
			.with_base_hue(180.0)
			.with_saturation(0.5)
			.with_lightness(0.7);

		assert_eq!(generator.base_hue, 180.0);
		assert_eq!(generator.saturation, 0.5);
		assert_eq!(generator.lightness, 0.7);
	}

	#[test]
	fn test_saturation_clamping() {
		let generator = ColorGenerator::new().with_saturation(1.5);
		assert_eq!(generator.saturation, 1.0);

		let generator = ColorGenerator::new().with_saturation(-0.5);
		assert_eq!(generator.saturation, 0.0);
	}

	#[test]
	fn test_lightness_clamping() {
		let generator = ColorGenerator::new().with_lightness(1.5);
		assert_eq!(generator.lightness, 1.0);

		let generator = ColorGenerator::new().with_lightness(-0.5);
		assert_eq!(generator.lightness, 0.0);
	}

	#[test]
	fn test_generate_color() {
		let generator = ColorGenerator::default();

		// Same hash should produce same color
		let color1 = generator.generate_color(42);
		let color2 = generator.generate_color(42);
		assert_eq!(color1, color2);

		// Different hashes should produce different colors
		let color3 = generator.generate_color(100);
		assert_ne!(color1, color3);
	}

	#[test]
	fn test_generate_color_for() {
		let generator = ColorGenerator::default();

		// Same value should produce same color
		let color1 = generator.generate_color_for(&"test");
		let color2 = generator.generate_color_for(&"test");
		assert_eq!(color1, color2);

		// Different values should produce different colors
		let color3 = generator.generate_color_for(&"other");
		assert_ne!(color1, color3);
	}
}