/**
 * XFlow AI Utility — OpenRouter & Google Gemini Integration (Updated for May 2026 Models)
 */

const OPENROUTER_BASE_URL = 'https://openrouter.ai/api/v1/chat/completions'

/** Доступные модели с описанием для выбора в UI */
export const AI_MODELS = {
  /** Сложные инженерные и архитектурные задачи, высокая стабильность */
  laguna: 'poolside/laguna-m.1:free',
  /** MoE 120B тяжёлая аналитика, архитектурный анализ, сложные рассуждения */
  nemotron: 'nvidia/nemotron-3-super-120b-a12b:free',
  /** Прямой вызов Gemini 3.5 Flash */
  geminiFlash: 'gemini-3.5-flash',
  /** Прямой вызов Gemini 3.1 Pro Preview */
  geminiPro: 'gemini-3.1-pro-preview',
  /** Прямой вызов Gemini 3.1 Flash Lite */
  geminiLite: 'gemini-3.1-flash-lite'
} as const

export type AiModelKey = keyof typeof AI_MODELS

/** Дефолтная модель, если не указана */
const DEFAULT_MODEL: AiModelKey = 'geminiFlash'

export const generateAIResponse = async (
  prompt: string,
  systemPrompt = 'You are a helpful assistant.',
  modelKey?: AiModelKey | string,
): Promise<string> => {
  // Получаем ключи из окружения
  const openRouterKey = process.env.NUXT_OPEN_ROUTER_API_KEY || process.env.OPEN_ROUTER_API_KEY
  const geminiKey = process.env.GEMINI_API_KEY || process.env.NUXT_GEMINI_API_KEY || process.env.GOOGLE_API_KEY

  // Резолвим модель: принимаем как ключ ('laguna') так и полное имя
  const resolvedModel: string =
    modelKey && modelKey in AI_MODELS
      ? AI_MODELS[modelKey as AiModelKey]
      : modelKey && (modelKey.includes('/') || modelKey.startsWith('gemini'))
        ? modelKey
        : AI_MODELS[DEFAULT_MODEL]

  // Определяем, использовать ли Gemini напрямую
  const useGeminiDirect = resolvedModel.startsWith('gemini') || (!openRouterKey && geminiKey)

  if (useGeminiDirect) {
    if (!geminiKey) {
      throw new Error('Gemini API key (GEMINI_API_KEY or GOOGLE_API_KEY) is not configured')
    }
    const geminiModel = resolvedModel.startsWith('gemini') ? resolvedModel : 'gemini-3.5-flash'
    console.log(`[AI] Direct Google Gemini call: ${geminiModel}`)

    try {
      const url = `https://generativelanguage.googleapis.com/v1beta/models/${geminiModel}:generateContent?key=${geminiKey}`
      const response = await $fetch<any>(url, {
        method: 'POST',
        headers: {
          'Content-Type': 'application/json'
        },
        body: {
          contents: [
            {
              role: 'user',
              parts: [{ text: prompt }]
            }
          ],
          systemInstruction: {
            parts: [{ text: systemPrompt }]
          },
          generationConfig: {
            temperature: 0.3
          }
        }
      })

      const content = response?.candidates?.[0]?.content?.parts?.[0]?.text
      if (!content) {
        throw new Error('Empty response from Gemini API')
      }
      return content
    } catch (error: any) {
      console.error(`[AI] Gemini direct error:`, error?.data || error?.message)
      throw new Error(`Gemini direct generation failed: ${error?.message || error?.toString()}`)
    }
  }

  // Иначе используем OpenRouter
  if (!openRouterKey) {
    throw new Error('Neither OPEN_ROUTER_API_KEY nor GEMINI_API_KEY is configured')
  }

  console.log(`[AI] OpenRouter call: ${resolvedModel}`)

  try {
    const response = await $fetch<any>(OPENROUTER_BASE_URL, {
      method: 'POST',
      headers: {
        'Authorization': `Bearer ${openRouterKey}`,
        'Content-Type': 'application/json',
        'HTTP-Referer': 'https://a-crm.controlsystem.kz',
        'X-Title': 'XFlow AI Node',
      },
      body: {
        model: resolvedModel,
        messages: [
          { role: 'system', content: systemPrompt },
          { role: 'user', content: prompt },
        ],
        stream: false,
      },
    })

    const content = response?.choices?.[0]?.message?.content
    if (!content) {
      throw new Error('Empty response from OpenRouter model')
    }
    return content
  } catch (error: any) {
    console.error(`[AI] OpenRouter error with model ${resolvedModel}:`, error?.data || error?.message)
    throw new Error(`OpenRouter generation failed (${resolvedModel}): ${error?.message}`)
  }
}

/** Хелпер: список моделей для фронтенда */
export const getAvailableModels = () =>
  Object.entries(AI_MODELS).map(([key, modelId]) => ({
    key,
    modelId,
    label: modelLabels[key as AiModelKey],
  }))

const modelLabels: Record<AiModelKey, string> = {
  laguna: '🏊 Laguna M.1 — стабильная инженерная (Claude via OpenRouter)',
  nemotron: '🔬 Nemotron Super 120B — тяжёлая аналитика (NVIDIA via OpenRouter)',
  geminiFlash: '⚡ Gemini 3.5 Flash — быстрая и стабильная (Google Direct)',
  geminiPro: '🧠 Gemini 3.1 Pro — продвинутая аналитика (Google Direct)',
  geminiLite: '🍃 Gemini 3.1 Flash Lite — экономичная (Google Direct)'
}