import type { ThemeExtractionResult } from '@/schema/theme-extraction';
import { baseCSS } from '@/server/lib/styles/base-css';
import { themeVariableGenerator } from '@/server/lib/styles/theme-variables';

export interface ThemeCustomizationOptions {
  enableCache?: boolean;
  validateColors?: boolean;
  checkAccessibility?: boolean;
  performanceMode?: boolean;
}

export interface ThemeValidationResult {
  isValid: boolean;
  errors: string[];
  warnings: string[];
}

export interface CSSGenerationResult {
  fullCSS: string;
  themeCSS: string;
  baseCSS: string;
  cacheHit: boolean;
  generationTimeMs: number;
}

interface ThemeCacheEntry {
  css: string;
  themeCSS: string;
  timestamp: number;
  cacheKey: string;
}

export class ThemeCustomizer {
  private cache = new Map<string, ThemeCacheEntry>();
  private readonly CACHE_TTL_MS = 1000 * 60 * 60; // 1時間
  private readonly MAX_CACHE_SIZE = 100;

  constructor(private options: ThemeCustomizationOptions = {}) {
    this.options = {
      enableCache: true,
      validateColors: true,
      checkAccessibility: true,
      performanceMode: false,
      ...options,
    };
  }

  generateThemedCSS(theme: ThemeExtractionResult): CSSGenerationResult {
    const startTime = performance.now();

    try {
      // バリデーション実行
      if (this.options.validateColors) {
        const validation = this.validateTheme(theme);
        if (!validation.isValid) {
          throw new Error(`テーマバリデーションエラー: ${validation.errors.join(', ')}`);
        }
      }

      // キャッシュキー生成
      const cacheKey = this.generateCacheKey(theme);

      // キャッシュチェック
      if (this.options.enableCache) {
        const cached = this.getCachedResult(cacheKey);
        if (cached) {
          return {
            fullCSS: cached.css,
            themeCSS: cached.themeCSS,
            baseCSS,
            cacheHit: true,
            generationTimeMs: performance.now() - startTime,
          };
        }
      }

      // CSS生成
      const themeCSS = themeVariableGenerator.generateThemeCSS(theme);
      const fullCSS = this.combineCSS(baseCSS, themeCSS);

      // キャッシュ保存
      if (this.options.enableCache) {
        this.setCachedResult(cacheKey, fullCSS, themeCSS);
      }

      const generationTimeMs = performance.now() - startTime;

      return {
        fullCSS,
        themeCSS,
        baseCSS,
        cacheHit: false,
        generationTimeMs,
      };
    } catch (error) {
      console.error('[ThemeCustomizer] CSS生成エラー:', error);

      // フォールバック: ベースCSSのみ返す
      return {
        fullCSS: baseCSS,
        themeCSS: '',
        baseCSS,
        cacheHit: false,
        generationTimeMs: performance.now() - startTime,
      };
    }
  }

  validateTheme(theme: ThemeExtractionResult): ThemeValidationResult {
    const errors: string[] = [];
    const warnings: string[] = [];

    try {
      // カラーコード形式の検証
      const colorEntries = Object.entries(theme.colors);

      for (const [key, color] of colorEntries) {
        if (!this.isValidHexColor(color)) {
          errors.push(`${key}: 無効なカラーコード形式 (${color})`);
        }
      }

      // アクセシビリティチェック
      if (this.options.checkAccessibility) {
        const accessibilityWarnings = this.checkColorAccessibility(theme);
        warnings.push(...accessibilityWarnings);
      }

      return {
        isValid: errors.length === 0,
        errors,
        warnings,
      };
    } catch (error) {
      console.error('[ThemeCustomizer] バリデーションエラー:', error);
      return {
        isValid: false,
        errors: ['バリデーション処理中にエラーが発生しました'],
        warnings: [],
      };
    }
  }

  private isValidHexColor(color: string): boolean {
    const hexColorRegex = /^#[0-9A-Fa-f]{6}$/;
    return hexColorRegex.test(color);
  }

  private checkColorAccessibility(theme: ThemeExtractionResult): string[] {
    const warnings: string[] = [];

    try {
      // 主要な色の組み合わせのコントラスト比をチェック
      const contrastPairs = [
        { fg: theme.colors.primary_text_color, bg: theme.colors.primary_background_color, name: 'プライマリテキスト/背景' },
        { fg: theme.colors.secondary_text_color, bg: theme.colors.secondary_background_color, name: 'セカンダリテキスト/背景' },
        { fg: theme.colors.inverse_text_color, bg: theme.colors.tertiary_background_color, name: '反転テキスト/背景' },
      ];

      for (const pair of contrastPairs) {
        const contrast = this.calculateContrastRatio(pair.fg, pair.bg);
        if (contrast < 4.5) {
          warnings.push(`${pair.name}: コントラスト比が低すぎます (${contrast.toFixed(2)}:1)`);
        }
      }
    } catch (error) {
      console.warn('[ThemeCustomizer] アクセシビリティチェック中のエラー:', error);
    }

    return warnings;
  }

  private calculateContrastRatio(color1: string, color2: string): number {
    try {
      const luminance1 = this.getLuminance(color1);
      const luminance2 = this.getLuminance(color2);

      const lighter = Math.max(luminance1, luminance2);
      const darker = Math.min(luminance1, luminance2);

      return (lighter + 0.05) / (darker + 0.05);
    } catch (error) {
      console.warn('コントラスト比計算エラー:', error);
      return 1;
    }
  }

  private getLuminance(hex: string): number {
    try {
      const rgb = this.hexToRgb(hex);
      if (!rgb) return 0;

      const [r, g, b] = [rgb.r, rgb.g, rgb.b].map((c) => {
        c = c / 255;
        return c <= 0.03928 ? c / 12.92 : Math.pow((c + 0.055) / 1.055, 2.4);
      });

      return 0.2126 * r + 0.7152 * g + 0.0722 * b;
    } catch (error) {
      console.warn('輝度計算エラー:', error);
      return 0;
    }
  }

  private hexToRgb(hex: string): { r: number; g: number; b: number } | null {
    const result = /^#?([a-f\d]{2})([a-f\d]{2})([a-f\d]{2})$/i.exec(hex);
    return result
      ? {
          r: parseInt(result[1], 16),
          g: parseInt(result[2], 16),
          b: parseInt(result[3], 16),
        }
      : null;
  }

  private generateCacheKey(theme: ThemeExtractionResult): string {
    // テーマの内容をハッシュ化してキャッシュキーを生成
    const themeString = JSON.stringify(theme.colors);
    return this.simpleHash(themeString);
  }

  private simpleHash(str: string): string {
    let hash = 0;
    for (let i = 0; i < str.length; i++) {
      const char = str.charCodeAt(i);
      hash = (hash << 5) - hash + char;
      hash = hash & hash; // 32bit整数に変換
    }
    return Math.abs(hash).toString(36);
  }

  private getCachedResult(cacheKey: string): ThemeCacheEntry | null {
    const entry = this.cache.get(cacheKey);

    if (!entry) {
      return null;
    }

    // TTL チェック
    if (Date.now() - entry.timestamp > this.CACHE_TTL_MS) {
      this.cache.delete(cacheKey);
      return null;
    }

    return entry;
  }

  private setCachedResult(cacheKey: string, fullCSS: string, themeCSS: string): void {
    // キャッシュサイズ制限
    if (this.cache.size >= this.MAX_CACHE_SIZE) {
      // 最も古いエントリを削除
      const oldestKey = this.cache.keys().next().value;
      if (oldestKey) {
        this.cache.delete(oldestKey);
      }
    }

    this.cache.set(cacheKey, {
      css: fullCSS,
      themeCSS,
      timestamp: Date.now(),
      cacheKey,
    });
  }

  private combineCSS(base: string, theme: string): string {
    return `${theme}\n\n${base}`;
  }

  // キャッシュ管理メソッド
  clearCache(): void {
    this.cache.clear();
  }

  getCacheStats(): { size: number; maxSize: number; hitRate?: number } {
    return {
      size: this.cache.size,
      maxSize: this.MAX_CACHE_SIZE,
    };
  }

  // デバッグ用メソッド
  debugTheme(theme: ThemeExtractionResult): {
    validation: ThemeValidationResult;
    cacheKey: string;
    generatedVariables: string;
  } {
    const validation = this.validateTheme(theme);
    const cacheKey = this.generateCacheKey(theme);
    const generatedVariables = themeVariableGenerator.generateThemeCSS(theme);

    return {
      validation,
      cacheKey,
      generatedVariables,
    };
  }
}

// デフォルトインスタンス
export const defaultThemeCustomizer = new ThemeCustomizer();