/**
 * Summarize Handler - Stop
 *
 * Runs in the Stop hook (120s timeout, not capped like SessionEnd).
 * This is the ONLY place where we can reliably wait for async work.
 *
 * Flow:
 * 1. Queue summarize request to worker
 * 2. Poll worker until summary processing completes
 * 3. Call /api/sessions/complete to clean up session
 *
 * SessionEnd (1.5s cap from Claude Code) is just a lightweight fallback —
 * all real work must happen here in Stop.
 */

import type { EventHandler, NormalizedHookInput, HookResult } from '../types.js';
import { ensureWorkerRunning, workerHttpRequest } from '../../shared/worker-utils.js';
import { logger } from '../../utils/logger.js';
import { extractLastMessage } from '../../shared/transcript-parser.js';
import { HOOK_EXIT_CODES, HOOK_TIMEOUTS, getTimeout } from '../../shared/hook-constants.js';

const SUMMARIZE_TIMEOUT_MS = getTimeout(HOOK_TIMEOUTS.DEFAULT);
const POLL_INTERVAL_MS = 500;
const MAX_WAIT_FOR_SUMMARY_MS = 110_000; // 110s — fits within Stop hook's 120s timeout

export const summarizeHandler: EventHandler = {
  async execute(input: NormalizedHookInput): Promise<HookResult> {
    // Ensure worker is running before any other logic
    const workerReady = await ensureWorkerRunning();
    if (!workerReady) {
      // Worker not available - skip summary gracefully
      return { continue: true, suppressOutput: true, exitCode: HOOK_EXIT_CODES.SUCCESS };
    }

    const { sessionId, transcriptPath } = input;

    // Validate required fields before processing
    if (!transcriptPath) {
      // No transcript available - skip summary gracefully (not an error)
      logger.debug('HOOK', `No transcriptPath in Stop hook input for session ${sessionId} - skipping summary`);
      return { continue: true, suppressOutput: true, exitCode: HOOK_EXIT_CODES.SUCCESS };
    }

    // Extract last assistant message from transcript (the work Claude did)
    // Note: "user" messages in transcripts are mostly tool_results, not actual user input.
    // The user's original request is already stored in user_prompts table.
    let lastAssistantMessage = '';
    try {
      lastAssistantMessage = extractLastMessage(transcriptPath, 'assistant', true);
    } catch (err) {
      logger.warn('HOOK', `Stop hook: failed to extract last assistant message for session ${sessionId}: ${err instanceof Error ? err.message : err}`);
      return { continue: true, suppressOutput: true, exitCode: HOOK_EXIT_CODES.SUCCESS };
    }

    // Skip summary if transcript has no assistant message (prevents repeated
    // empty summarize requests that pollute logs — upstream bug)
    if (!lastAssistantMessage || !lastAssistantMessage.trim()) {
      logger.debug('HOOK', 'No assistant message in transcript - skipping summary', {
        sessionId,
        transcriptPath
      });
      return { continue: true, suppressOutput: true, exitCode: HOOK_EXIT_CODES.SUCCESS };
    }

    logger.dataIn('HOOK', 'Stop: Requesting summary', {
      hasLastAssistantMessage: !!lastAssistantMessage
    });

    // 1. Queue summarize request — worker returns immediately with { status: 'queued' }
    const response = await workerHttpRequest('/api/sessions/summarize', {
      method: 'POST',
      headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify({
        contentSessionId: sessionId,
        last_assistant_message: lastAssistantMessage
      }),
      timeoutMs: SUMMARIZE_TIMEOUT_MS
    });

    if (!response.ok) {
      return { continue: true, suppressOutput: true };
    }

    logger.debug('HOOK', 'Summary request queued, waiting for completion');

    // 2. Poll worker until pending work for this session is done.
    //    This keeps the Stop hook alive (120s timeout) so the SDK agent
    //    can finish processing the summary before SessionEnd kills the session.
    const waitStart = Date.now();
    let summaryStored: boolean | null = null;
    while ((Date.now() - waitStart) < MAX_WAIT_FOR_SUMMARY_MS) {
      await new Promise(resolve => setTimeout(resolve, POLL_INTERVAL_MS));
      try {
        const statusResponse = await workerHttpRequest(`/api/sessions/status?contentSessionId=${encodeURIComponent(sessionId)}`, {
          timeoutMs: 5000
        });
        const status = await statusResponse.json() as { queueLength?: number; summaryStored?: boolean | null };
        const queueLength = status.queueLength ?? 0;
        // Only treat an empty queue as completion when the session exists (non-404).
        // A 404 means the session was not found — not that processing finished.
        if (queueLength === 0 && statusResponse.status !== 404) {
          summaryStored = status.summaryStored ?? null;
          logger.info('HOOK', 'Summary processing complete', {
            waitedMs: Date.now() - waitStart,
            summaryStored
          });
          // Warn when the agent processed a summarize request but produced no storable summary.
          // This is the silent-failure path described in #1633: queue empties but no summary record exists.
          if (summaryStored === false) {
            logger.warn('HOOK', 'Summary was not stored: LLM response likely lacked valid <summary> tags (#1633)', {
              sessionId,
              waitedMs: Date.now() - waitStart
            });
          }
          break;
        }
      } catch {
        // Worker may be busy — keep polling
      }
    }

    // 3. Complete the session — clean up active sessions map.
    //    This runs here in Stop (120s timeout) instead of SessionEnd (1.5s cap)
    //    so it reliably fires after summary work is done.
    try {
      await workerHttpRequest('/api/sessions/complete', {
        method: 'POST',
        headers: { 'Content-Type': 'application/json' },
        body: JSON.stringify({ contentSessionId: sessionId }),
        timeoutMs: 10_000
      });
      logger.info('HOOK', 'Session completed in Stop hook', { contentSessionId: sessionId });
    } catch (err) {
      logger.warn('HOOK', `Stop hook: session-complete failed: ${err instanceof Error ? err.message : err}`);
    }

    return { continue: true, suppressOutput: true };
  }
};