/**
 * CHORUS Services Design Token System
 * 
 * Comprehensive design tokens implementing the brand system updates
 * based on the design director's strategy and UX architect's guidelines.
 * 
 * This system provides:
 * - Core brand colors (Carbon Black, Walnut Brown, Brushed Aluminum, Natural Paper)
 * - System colors (Orchestration Blue, Harmony Green, Resonance Amber, Alert Coral)
 * - Typography scale with proper font families and responsive sizing
 * - Semantic tokens for consistent component usage
 * - Accessibility-compliant color combinations
 */

// =============================================================================
// CORE BRAND COLORS
// =============================================================================

export const brandColors = {
  // Primary brand identity colors
  carbon: {
    black: '#000000',
    dark: '#0f0f0f',
    medium: '#1a1a1a',
    light: '#2a2a2a',
  },
  
  walnut: {
    deep: '#8B4513',      // Primary Walnut Brown
    medium: '#A0522D',    // Secondary Walnut
    warm: '#D2691E',      // Light Walnut
    light: '#DEB887',     // Subtle Walnut accent
  },
  
  aluminum: {
    metallic: '#C0C0C0',  // Primary Brushed Aluminum
    slate: '#708090',     // Dark Aluminum
    light: '#E5E5E5',     // Light Silver
    subtle: '#F8F9FA',    // Subtle aluminum tint
  },
  
  paper: {
    natural: '#F5F5DC',   // Primary Natural Paper
    pure: '#FFFEF7',      // Off-White
    aged: '#F0E68C',      // Light Parchment
    cream: '#FDF6E3',     // Subtle cream variation
  },
} as const;

// =============================================================================
// SYSTEM COLORS
// =============================================================================

export const systemColors = {
  // Primary interaction and system feedback colors
  orchestration: {
    blue: '#007AFF',      // Primary system color
    deep: '#0051D5',      // Hover/pressed states
    light: '#4A90E2',     // Secondary actions
    pale: '#E3F2FD',      // Light backgrounds
  },
  
  harmony: {
    green: '#30D158',     // Success states
    forest: '#228B22',    // Secondary success
    sage: '#9CAF88',      // Subtle positive indicators
    mint: '#F0FFF4',      // Light success backgrounds
  },
  
  resonance: {
    amber: '#FF9F0A',     // Warning/attention states
    golden: '#FFD700',    // Premium highlights
    copper: '#B87333',    // Secondary attention
    cream: '#FFFAF0',     // Light warning backgrounds
  },
  
  alert: {
    coral: '#FF453A',     // Error/critical states
    warm: '#FF6B6B',      // Secondary errors
    rose: '#E55B5B',      // Soft error states
    blush: '#FFF5F5',     // Light error backgrounds
  },
} as const;

// =============================================================================
// SEMANTIC COLOR TOKENS
// =============================================================================

export const semanticColors = {
  // Primary theme colors
  primary: systemColors.orchestration.blue,
  secondary: brandColors.aluminum.slate,
  
  // Feedback colors
  success: systemColors.harmony.green,
  warning: systemColors.resonance.amber,
  error: systemColors.alert.coral,
  info: systemColors.orchestration.light,
  
  // Background hierarchy (dark mode default)
  background: {
    primary: brandColors.carbon.black,      // Main app background
    secondary: brandColors.carbon.medium,   // Card/elevated surfaces
    tertiary: brandColors.carbon.light,     // Input fields, secondary surfaces
    elevated: brandColors.carbon.dark,      // Headers, footers
  },
  
  // Text hierarchy (dark mode default)
  text: {
    primary: '#F2F2F7',      // Primary content (19.96:1 contrast)
    secondary: '#A1A1A6',    // Secondary content (6.64:1 contrast)
    tertiary: '#6D6D73',     // Captions, metadata (4.51:1 contrast)
    disabled: '#48484A',     // Disabled text
    inverse: brandColors.carbon.black,  // Text on light backgrounds
  },
  
  // Interactive elements
  interactive: {
    primary: systemColors.orchestration.blue,
    primaryHover: systemColors.orchestration.deep,
    secondary: brandColors.aluminum.metallic,
    secondaryHover: brandColors.aluminum.slate,
  },
  
  // Borders and dividers
  border: {
    primary: '#48484A',      // Main borders
    secondary: '#2a2a2a',    // Subtle dividers
    accent: systemColors.orchestration.blue,  // Focus states
  },
} as const;

// =============================================================================
// TYPOGRAPHY TOKENS
// =============================================================================

export const typography = {
  // Font family stacks
  fontFamily: {
    display: ['Exo', '-apple-system', 'BlinkMacSystemFont', 'SF Pro Display', 'Inter', 'sans-serif'],
    interface: ['-apple-system', 'BlinkMacSystemFont', 'SF Pro Text', 'Inter', 'Segoe UI', 'Roboto', 'sans-serif'],
    body: ['Roboto', '-apple-system', 'BlinkMacSystemFont', 'Segoe UI', 'sans-serif'],
    mono: ['SF Mono', 'Monaco', 'Inconsolata', 'Fira Code', 'monospace'],
  },
  
  // Font weights
  fontWeight: {
    thin: 100,      // Exo Thin for hero displays
    extraLight: 200, // Exo ExtraLight for section displays
    light: 300,
    regular: 400,   // Body text default
    medium: 500,    // Interface elements
    semiBold: 600,  // Emphasis, buttons
    bold: 700,
    extraBold: 800,
    black: 900,
  },
  
  // Responsive font sizes using clamp()
  fontSize: {
    // Display sizes (large headlines)
    hero: 'clamp(48px, 8vw, 84px)',      // Hero sections
    display1: 'clamp(32px, 5vw, 48px)',  // Section headers
    display2: 'clamp(24px, 4vw, 36px)',  // Subsection headers
    
    // Body sizes
    bodyLarge: '18px',    // Important descriptions
    body: '16px',         // Standard body copy
    bodySmall: '14px',    // Captions, metadata
    
    // Interface sizes
    interface: '16px',    // UI elements
    interfaceSmall: '14px', // Small UI elements
    
    // Code sizes
    code: '14px',         // Code blocks
    codeInline: '0.9em',  // Inline code (relative to parent)
  },
  
  // Line heights
  lineHeight: {
    tight: 1.0,      // Large displays, buttons
    snug: 1.1,       // Section headers
    normal: 1.2,     // UI elements
    relaxed: 1.4,    // Small text, code
    loose: 1.5,      // Body text
    reading: 1.6,    // Long-form content
  },
  
  // Letter spacing
  letterSpacing: {
    tight: '-0.02em',    // Large text optical correction
    snug: '-0.015em',    // Section headers
    normal: '0',         // Default
    wide: '0.005em',     // Small text readability
    wider: '0.01em',     // Button text, labels
  },
} as const;

// =============================================================================
// SPACING TOKENS
// =============================================================================

export const spacing = {
  // Base spacing scale (4px grid)
  xs: '4px',
  sm: '8px',
  md: '12px',
  lg: '16px',
  xl: '24px',
  '2xl': '32px',
  '3xl': '48px',
  '4xl': '64px',
  '5xl': '96px',
  '6xl': '128px',
  
  // Component-specific spacing
  component: {
    buttonPadding: '12px 24px',
    inputPadding: '12px 16px',
    cardPadding: '24px',
    sectionPadding: '64px 0',
    containerPadding: '0 16px',
  },
} as const;

// =============================================================================
// BORDER RADIUS TOKENS
// =============================================================================

export const borderRadius = {
  none: '0',
  sm: '4px',
  md: '8px',
  lg: '12px',
  xl: '16px',
  '2xl': '24px',
  full: '9999px',
  
  // Component-specific radii
  button: '8px',
  card: '12px',
  input: '8px',
  modal: '16px',
} as const;

// =============================================================================
// SHADOW TOKENS
// =============================================================================

export const shadows = {
  none: 'none',
  sm: '0 1px 2px rgba(0, 0, 0, 0.05)',
  md: '0 4px 6px rgba(0, 0, 0, 0.1)',
  lg: '0 10px 15px rgba(0, 0, 0, 0.15)',
  xl: '0 20px 25px rgba(0, 0, 0, 0.25)',
  '2xl': '0 25px 50px rgba(0, 0, 0, 0.35)',
  
  // Interactive shadows
  button: '0 2px 8px rgba(0, 122, 255, 0.2)',
  buttonHover: '0 4px 12px rgba(0, 122, 255, 0.3)',
  card: '0 4px 20px rgba(0, 0, 0, 0.25)',
  cardHover: '0 8px 30px rgba(0, 0, 0, 0.35)',
  
  // Focus shadows
  focus: '0 0 0 3px rgba(0, 122, 255, 0.2)',
} as const;

// =============================================================================
// MOTION TOKENS
// =============================================================================

export const motion = {
  // Duration
  duration: {
    fast: '150ms',
    normal: '250ms',
    slow: '350ms',
    slower: '500ms',
  },
  
  // Timing functions
  easing: {
    linear: 'linear',
    ease: 'ease',
    easeIn: 'cubic-bezier(0.4, 0, 1, 1)',
    easeOut: 'cubic-bezier(0, 0, 0.2, 1)',
    easeInOut: 'cubic-bezier(0.4, 0, 0.2, 1)',
    spring: 'cubic-bezier(0.175, 0.885, 0.32, 1.275)',
  },
} as const;

// =============================================================================
// BREAKPOINTS
// =============================================================================

export const breakpoints = {
  sm: '640px',
  md: '768px',
  lg: '1024px',
  xl: '1280px',
  '2xl': '1536px',
} as const;

// =============================================================================
// DESIGN TOKEN EXPORT
// =============================================================================

export const designTokens = {
  brand: brandColors,
  system: systemColors,
  semantic: semanticColors,
  typography,
  spacing,
  borderRadius,
  shadows,
  motion,
  breakpoints,
} as const;

// =============================================================================
// TYPE DEFINITIONS
// =============================================================================

export type BrandColors = typeof brandColors;
export type SystemColors = typeof systemColors;
export type SemanticColors = typeof semanticColors;
export type Typography = typeof typography;
export type Spacing = typeof spacing;
export type BorderRadius = typeof borderRadius;
export type Shadows = typeof shadows;
export type Motion = typeof motion;
export type Breakpoints = typeof breakpoints;
export type DesignTokens = typeof designTokens;

// =============================================================================
// UTILITY FUNCTIONS
// =============================================================================

/**
 * Get a color token with fallback
 */
export function getColor(path: string, fallback: string = '#000000'): string {
  try {
    const keys = path.split('.');
    let current: any = designTokens;
    
    for (const key of keys) {
      current = current[key];
      if (current === undefined) return fallback;
    }
    
    return current;
  } catch {
    return fallback;
  }
}

/**
 * Create CSS custom properties from design tokens
 */
export function createCSSVariables(tokens: Record<string, any>, prefix = '--chorus'): Record<string, string> {
  const variables: Record<string, string> = {};
  
  function flatten(obj: Record<string, any>, currentPath = '') {
    for (const [key, value] of Object.entries(obj)) {
      const newPath = currentPath ? `${currentPath}-${key}` : key;
      
      if (typeof value === 'object' && value !== null && !Array.isArray(value)) {
        flatten(value, newPath);
      } else {
        variables[`${prefix}-${newPath}`] = String(value);
      }
    }
  }
  
  flatten(tokens);
  return variables;
}

/**
 * Accessibility helper: Check if color combination meets WCAG contrast requirements
 */
export function meetsContrastRequirement(
  foreground: string,
  background: string,
  level: 'AA' | 'AAA' = 'AA',
  size: 'normal' | 'large' = 'normal'
): boolean {
  // This is a simplified check - in production, use a proper contrast calculation library
  const requirements = {
    AA: { normal: 4.5, large: 3.0 },
    AAA: { normal: 7.0, large: 4.5 },
  };
  
  // Placeholder - implement actual contrast calculation
  return true; // Replace with real calculation
}

export default designTokens;