import type { FastifyInstance } from 'fastify';
import type { Config } from '../config.js';
import type { ModelInfo } from '../types/api.js';

interface ApiModelsResponse {
  data?: ModelInfo[];
}

const DEEPSEEK_STATIC_MODELS: ModelInfo[] = [
  { id: 'deepseek-v4-flash', object: 'model', created: 0, owned_by: 'deepseek' },
  { id: 'deepseek-v4-pro', object: 'model', created: 0, owned_by: 'deepseek' },
];

export function registerModelRoutes(app: FastifyInstance, config: Config): void {
  app.get('/api/models', async (_req, reply) => {
    const models: ModelInfo[] = [];

    // 1. Fetch llama-swap models
    try {
      const res = await fetch(`${config.LLAMA_SWAP_URL}/v1/models`);
      if (res.ok) {
        const parsed = (await res.json()) as ApiModelsResponse;
        if (parsed.data) models.push(...parsed.data);
      }
    } catch {
      // llama-swap unreachable — proceed with whatever we have
    }

    // 2. If DeepSeek is configured, fetch live models from their API
    if (config.DEEPSEEK_API_KEY) {
      try {
        const baseURL = (config.DEEPSEEK_BASE_URL ?? 'https://api.deepseek.com').replace(/\/+$/, '');
        const res = await fetch(`${baseURL}/v1/models`, {
          headers: { Authorization: `Bearer ${config.DEEPSEEK_API_KEY}` },
          signal: AbortSignal.timeout(5_000),
        });
        if (res.ok) {
          const parsed = (await res.json()) as ApiModelsResponse;
          if (parsed.data) models.push(...parsed.data);
        } else {
          // API call failed — fall back to static model list
          models.push(...DEEPSEEK_STATIC_MODELS);
        }
      } catch {
        // Network error — fall back to static model list
        models.push(...DEEPSEEK_STATIC_MODELS);
      }
    }

    if (models.length === 0) {
      reply.code(502);
      return { error: 'no models available from any provider' };
    }
    return models;
  });
}