import OpenAI from "openai";

export interface TrendPoint {
  date: string;
  value: number;
}

export class TrendsClient {
  private openai: OpenAI;

  constructor(apiKey?: string) {
    // Use environment key if available, otherwise expect it passed
    const key = apiKey || process.env.OPENROUTER_KEY || "dummy";
    this.openai = new OpenAI({
      apiKey: key,
      baseURL: "https://openrouter.ai/api/v1",
      defaultHeaders: {
        "HTTP-Referer": "https://mintel.me",
        "X-Title": "Mintel Trends Engine",
      },
    });
  }

  /**
   * Simulates interest over time using LLM knowledge to avoid flaky scraping.
   * This ensures the "Digital Architect" pipelines don't break on API changes.
   */
  async getInterestOverTime(
    keyword: string,
    geo: string = "DE",
  ): Promise<TrendPoint[]> {
    console.log(
      `📈 Simuliere Suchvolumen-Trend (AI-basiert) für: "${keyword}" (Region: ${geo})...`,
    );
    try {
      const response = await this.openai.chat.completions.create({
        model: "google/gemini-2.5-flash",
        messages: [
          {
            role: "system",
            content: `You are a data simulator. Generate a realistic Google Trends-style JSON dataset for the keyword "${keyword}" in "${geo}" over the last 5 years.
Rules:
- 12 data points (approx one every 6 months or represent key moments).
- Values between 0-100.
- JSON format: { "timeline": [{ "date": "YYYY-MM", "value": 50 }] }
- Return ONLY JSON.`,
          },
        ],
        response_format: { type: "json_object" },
      });

      const body = response.choices[0].message.content || "{}";
      const parsed = JSON.parse(body);
      return parsed.timeline || [];
    } catch (error) {
      console.warn(`Simulated Trend Error (${keyword}):`, error);
      // Fallback mock data
      return [
        { date: "2020-01", value: 20 },
        { date: "2021-01", value: 35 },
        { date: "2022-01", value: 50 },
        { date: "2023-01", value: 75 },
        { date: "2024-01", value: 95 },
      ];
    }
  }

  async getRelatedQueries(
    keyword: string,
    geo: string = "DE",
  ): Promise<string[]> {
    // Simple mock to avoid API calls
    return [
      `${keyword} optimization`,
      `${keyword} tutorial`,
      `${keyword} best practices`,
    ];
  }
}