import { createHandler } from './_shared/middleware'
import { adminDb } from './_shared/db'
import { resolveTypeId, resolveAgentId, resolvePromptConfigId } from './_shared/resolve-ids'
import { runAgent } from './_shared/index'
import { create } from './admin-data'

/**
 * @module custom_support-solution
 * @layer custom/cortex
 * @stability custom
 *
 * Solution AI — internal AI collaborator for support agents working a case.
 * Powered by core's runAgent() with the 'solution_ai' prompt config.
 * Never visible to the customer (all messages are visibility='internal').
 *
 * Two actions:
 *   POST ?action=start   — ensures an internal AI thread exists for the ticket,
 *                          sends the first message, returns thread + agent message.
 *   POST ?action=message — sends a follow-up message on the existing AI thread.
 *
 * Response: { threadId, agentMessageId, content }
 *
 * The AI thread is distinct from the regular internal thread: it is tagged with
 * data.thread_purpose = 'solution_ai' so the UI can find it deterministically.
 */

// ─── ACTION: START ─────────────────────────────────────────────────────────────

async function handleStart(ctx: any, body: any) {
  const { ticket_id, message } = body
  if (!ticket_id) throw new Error('ticket_id is required')
  if (!message) throw new Error('message is required')

  const [threadTypeId, solutionAgentId, promptConfigId] = await Promise.all([
    resolveTypeId('thread', 'support_thread'),
    resolveAgentId('Solution AI Agent'),
    resolvePromptConfigId('solution_ai'),
  ])

  // Find existing solution AI thread for this ticket
  const { data: existing } = await adminDb
    .from('threads')
    .select('id')
    .eq('target_type', 'items')
    .eq('target_id', ticket_id)
    .eq('visibility', 'internal')
    .eq('data->>thread_purpose', 'solution_ai')
    .maybeSingle()

  let threadId = existing?.id

  if (!threadId) {
    const thread = await create(ctx, {
      entity: 'threads',
      type_id: threadTypeId,
      target_type: 'items',
      target_id: ticket_id,
      visibility: 'internal',
      status: 'active',
      data: {
        thread_purpose: 'solution_ai',
        agent_id: solutionAgentId,
        prompt_config_id: promptConfigId,
      }
    })
    if (!thread?.id) throw new Error('Failed to create solution AI thread')
    threadId = thread.id
  }

  const agentMsg = await runAgent(threadId, message, ctx)

  return {
    threadId,
    agentMessageId: agentMsg?.id,
    content: agentMsg?.content || '',
  }
}

// ─── ACTION: MESSAGE ───────────────────────────────────────────────────────────

async function handleMessage(ctx: any, body: any) {
  const { thread_id, message } = body
  if (!thread_id) throw new Error('thread_id is required')
  if (!message) throw new Error('message is required')

  const agentMsg = await runAgent(thread_id, message, ctx)

  return {
    threadId: thread_id,
    agentMessageId: agentMsg?.id,
    content: agentMsg?.content || '',
  }
}

// ─── HANDLER ──────────────────────────────────────────────────────────────────

export const handler = createHandler(async (ctx, body) => {
  const action = (ctx as any).query?.action
  switch (action) {
    case 'start':   return handleStart(ctx, body)
    case 'message': return handleMessage(ctx, body)
    default: throw new Error(`Unknown action: ${action}. Use 'start' or 'message'.`)
  }
})