// Helper function to convert hex to RGB
export const hexToRgb = (hex: string): { r: number; g: number; b: number } => {
  // Remove the # if present
  hex = hex.replace("#", "")

  // Convert hex to RGB
  let r = 0,
    g = 0,
    b = 0
  if (hex.length === 3) {
    r = Number.parseInt(hex[0] + hex[0], 16)
    g = Number.parseInt(hex[1] + hex[1], 16)
    b = Number.parseInt(hex[2] + hex[2], 16)
  } else if (hex.length === 6) {
    r = Number.parseInt(hex.substring(0, 2), 16)
    g = Number.parseInt(hex.substring(2, 4), 16)
    b = Number.parseInt(hex.substring(4, 6), 16)
  }

  return { r, g, b }
}

// Helper function to convert RGB to HSL
export const rgbToHsl = (r: number, g: number, b: number): { h: number; s: number; l: number } => {
  r /= 255
  g /= 255
  b /= 255

  const max = Math.max(r, g, b)
  const min = Math.min(r, g, b)
  let h = 0,
    s = 0,
    l = (max + min) / 2

  if (max !== min) {
    const d = max - min
    s = l > 0.5 ? d / (2 - max - min) : d / (max + min)

    switch (max) {
      case r:
        h = (g - b) / d + (g < b ? 6 : 0)
        break
      case g:
        h = (b - r) / d + 2
        break
      case b:
        h = (r - g) / d + 4
        break
    }

    h /= 6
  }

  return {
    h: Math.round(h * 360),
    s: Math.round(s * 100),
    l: Math.round(l * 100),
  }
}

// Add this function if it doesn't exist
export function hexToHsl(hex: string): { h: number; s: number; l: number } {
  // Remove the # if present
  hex = hex.replace("#", "")

  // Convert hex to RGB
  let r = 0,
    g = 0,
    b = 0
  if (hex.length === 3) {
    r = Number.parseInt(hex[0] + hex[0], 16)
    g = Number.parseInt(hex[1] + hex[1], 16)
    b = Number.parseInt(hex[2] + hex[2], 16)
  } else if (hex.length === 6) {
    r = Number.parseInt(hex.substring(0, 2), 16)
    g = Number.parseInt(hex.substring(2, 4), 16)
    b = Number.parseInt(hex.substring(4, 6), 16)
  }

  // Convert RGB to HSL
  r /= 255
  g /= 255
  b /= 255

  const max = Math.max(r, g, b)
  const min = Math.min(r, g, b)
  let h = 0,
    s = 0,
    l = (max + min) / 2

  if (max !== min) {
    const d = max - min
    s = l > 0.5 ? d / (2 - max - min) : d / (max + min)

    switch (max) {
      case r:
        h = (g - b) / d + (g < b ? 6 : 0)
        break
      case g:
        h = (b - r) / d + 2
        break
      case b:
        h = (r - g) / d + 4
        break
    }

    h /= 6
  }

  return {
    h: Math.round(h * 360),
    s: Math.round(s * 100),
    l: Math.round(l * 100),
  }
}

// Calculate relative luminance using WCAG formula
export const calculateLuminance = (r: number, g: number, b: number): number => {
  // Normalize RGB values to 0-1
  const normalize = (value: number) => {
    const normalized = value / 255
    return normalized <= 0.03928 ? normalized / 12.92 : Math.pow((normalized + 0.055) / 1.055, 2.4)
  }

  const rNorm = normalize(r)
  const gNorm = normalize(g)
  const bNorm = normalize(b)

  return 0.2126 * rNorm + 0.7152 * gNorm + 0.0722 * bNorm
}

// Calculate luminance from hex color
export const hexToLuminance = (hex: string): number => {
  const { r, g, b } = hexToRgb(hex)
  return calculateLuminance(r, g, b)
}

// Convert luminance back to grayscale RGB values
export const luminanceToRgb = (luminance: number): { r: number; g: number; b: number } => {
  // Clamp luminance between 0.05 and 0.95 to avoid pure black/white
  const clampedLuminance = Math.max(0.05, Math.min(0.95, luminance))

  // Convert luminance to sRGB value
  const srgb =
    clampedLuminance <= 0.0031308 ? clampedLuminance * 12.92 : 1.055 * Math.pow(clampedLuminance, 1 / 2.4) - 0.055

  const value = Math.round(srgb * 255)
  return { r: value, g: value, b: value }
}

// Convert RGB to hex
export const rgbToHex = (r: number, g: number, b: number): string => {
  return `#${r.toString(16).padStart(2, "0")}${g.toString(16).padStart(2, "0")}${b.toString(16).padStart(2, "0")}`
}

// Main function to derive secondary text color from primary text color
export const deriveSecondaryTextColor = (primaryTextColor: string, backgroundColor: string): string => {
  const primaryLuminance = hexToLuminance(primaryTextColor)
  const backgroundLuminance = hexToLuminance(backgroundColor)

  // Determine if background is light or dark
  const isLightBackground = backgroundLuminance > 0.5

  // Calculate secondary luminance with 0.18 difference
  let secondaryLuminance: number
  if (isLightBackground) {
    // For light backgrounds, make secondary text lighter (higher luminance)
    secondaryLuminance = primaryLuminance + 0.18
  } else {
    // For dark backgrounds, make secondary text darker (lower luminance)
    secondaryLuminance = primaryLuminance - 0.18
  }

  // Convert back to RGB and then to hex
  const { r, g, b } = luminanceToRgb(secondaryLuminance)
  return rgbToHex(r, g, b)
}