/**
 * Services: Business logic layer.
 * 
 * This module contains the business logic for the application.
 * Services coordinate between controllers and repositories.
 */

import type { AgentRequest, AgentResponse, AgentConnection } from '../models'

/**
 * Build OpenAI client and full prompt from request body.
 * Returns { openai, modelId, fullPrompt } or { error }.
 */
export function buildAgentRequest(body: AgentRequest): { openai: unknown; modelId: string; fullPrompt: string } | { error: string } {
  const { prompt, context, contextNodes, connection: conn, reasoning } = body ?? {}
  const reasoningEnabled = Boolean(reasoning)
  let baseURL = process.env.AI_BASE_URL?.trim() || null
  let apiKey = process.env.OPENAI_API_KEY?.trim() || null
  let modelId = process.env.AI_MODEL?.trim() || (baseURL ? 'local-model' : 'gpt-4o-mini')
  
  if (conn && typeof conn === 'object') {
    const c = conn as AgentConnection
    const provider = c.provider === 'openai' ? 'openai' : 'local'
    if (provider === 'local') {
      baseURL = (typeof c.baseURL === 'string' && c.baseURL.trim()) ? c.baseURL.trim() : baseURL
      apiKey = (typeof c.apiKey === 'string' && c.apiKey.trim()) ? c.apiKey.trim() : (apiKey || 'lm-studio')
    } else {
      baseURL = null
      apiKey = (typeof c.apiKey === 'string' && c.apiKey.trim()) ? c.apiKey.trim() : apiKey
    }
    if (typeof c.model === 'string' && c.model.trim()) modelId = c.model.trim()
  }
  
  if (!baseURL && !apiKey) {
    return { error: 'No AI configured. Set connection in Settings (AI) or env: OPENAI_API_KEY or AI_BASE_URL.' }
  }
  
  const basePrompt = [
    typeof prompt === 'string' ? prompt : 'No prompt provided.',
    context && typeof context === 'string' ? `\n\nAdditional context:\n${context}` : '',
    Array.isArray(contextNodes) && contextNodes.length > 0
      ? `\n\nContext from connected nodes:\n${contextNodes.map((n) => (n.content != null ? n.content : `${n.id}: (no content)`)).join('\n\n')}`
      : '',
  ].join('')
  
  const fullPrompt = reasoningEnabled
    ? basePrompt + '\n\nRespond in exactly two markdown sections. First: "## Reasoning" with your step-by-step reasoning. Then: "## Output" with only the final answer. No preamble.'
    : basePrompt + '\n\nRespond with structured markdown only. No preamble.'
  
  const { createOpenAI } = require('@ai-sdk/openai')
  const openai = createOpenAI({
    apiKey: apiKey || 'lm-studio',
    ...(baseURL && { baseURL, compatibility: 'compatible' }),
  })
  
  return { openai, modelId, fullPrompt }
}

/**
 * Process agent response
 */
export function processAgentResponse(result: { text?: string }): AgentResponse {
  const markdown = result?.text ?? ''
  return { markdown }
}