/**
 * AI Service Factory
 *
 * Provider selection (priority order):
 *   1. VITE_AI_PROVIDER=openrouter  → OpenRouterAIService (requires VITE_OPENROUTER_API_KEY)
 *   2. VITE_AI_PROVIDER=mock        → MockAIService (deterministic, no API key required)
 *   3. VITE_USE_REAL_AI=true        → OpenRouterAIService (legacy flag, requires VITE_OPENROUTER_API_KEY)
 *   4. (default)                    → MockAIService
 *
 * If VITE_AI_PROVIDER=openrouter but VITE_OPENROUTER_API_KEY is missing, the factory
 * logs a warning and falls back to MockAIService — never silently fails.
 *
 * Optional: VITE_OPENROUTER_MODEL controls which model OpenRouter uses.
 * Default: anthropic/claude-3-5-haiku
 */
import { MockAIService } from './mock/MockAIService'
import { OpenRouterAIService } from './openrouter/OpenRouterAIService'
import type { IAIService } from './IAIService'

function resolveProvider(): IAIService {
  const provider = import.meta.env.VITE_AI_PROVIDER as string | undefined
  const legacyRealAI = import.meta.env.VITE_USE_REAL_AI === 'true'
  const apiKey = import.meta.env.VITE_OPENROUTER_API_KEY as string | undefined

  const wantsOpenRouter = provider === 'openrouter' || (legacyRealAI && !provider)

  if (wantsOpenRouter) {
    if (!apiKey) {
      console.warn(
        '[aiService] OpenRouter selected but VITE_OPENROUTER_API_KEY is missing — falling back to MockAIService.',
        'Set VITE_AI_PROVIDER=mock to suppress this warning.',
      )
      return MockAIService
    }
    return OpenRouterAIService
  }

  return MockAIService
}

export const aiService: IAIService = resolveProvider()

export { MockAIService, OpenRouterAIService }
export type { IAIService }