/**
 * Session retrieval functions
 * Database-first parameter pattern for functional composition
 */

import type { Database } from 'bun:sqlite';
import { logger } from '../../../utils/logger.js';
import type {
  SessionBasic,
  SessionFull,
  SessionWithStatus,
  SessionSummaryDetail,
} from './types.js';

/**
 * Get session by ID (basic fields only)
 */
export function getSessionById(db: Database, id: number): SessionBasic | null {
  const stmt = db.prepare(`
    SELECT id, content_session_id, memory_session_id, project,
           COALESCE(platform_source, 'claude') as platform_source,
           user_prompt, custom_title
    FROM sdk_sessions
    WHERE id = ?
    LIMIT 1
  `);

  return (stmt.get(id) as SessionBasic | undefined) || null;
}

/**
 * Get SDK sessions by memory session IDs
 * Used for exporting session metadata
 */
export function getSdkSessionsBySessionIds(
  db: Database,
  memorySessionIds: string[]
): SessionFull[] {
  if (memorySessionIds.length === 0) return [];

  const placeholders = memorySessionIds.map(() => '?').join(',');
  const stmt = db.prepare(`
    SELECT id, content_session_id, memory_session_id, project,
           COALESCE(platform_source, 'claude') as platform_source,
           user_prompt, custom_title,
           started_at, started_at_epoch, completed_at, completed_at_epoch, status
    FROM sdk_sessions
    WHERE memory_session_id IN (${placeholders})
    ORDER BY started_at_epoch DESC
  `);

  return stmt.all(...memorySessionIds) as SessionFull[];
}

/**
 * Get recent sessions with their status and summary info
 * Returns sessions ordered oldest-first for display
 */
export function getRecentSessionsWithStatus(
  db: Database,
  project: string,
  limit: number = 3
): SessionWithStatus[] {
  const stmt = db.prepare(`
    SELECT * FROM (
      SELECT
        s.memory_session_id,
        s.status,
        s.started_at,
        s.started_at_epoch,
        s.user_prompt,
        CASE WHEN sum.memory_session_id IS NOT NULL THEN 1 ELSE 0 END as has_summary
      FROM sdk_sessions s
      LEFT JOIN session_summaries sum ON s.memory_session_id = sum.memory_session_id
      WHERE s.project = ? AND s.memory_session_id IS NOT NULL
      GROUP BY s.memory_session_id
      ORDER BY s.started_at_epoch DESC
      LIMIT ?
    )
    ORDER BY started_at_epoch ASC
  `);

  return stmt.all(project, limit) as SessionWithStatus[];
}

/**
 * Get full session summary by ID (includes request_summary and learned_summary)
 */
export function getSessionSummaryById(
  db: Database,
  id: number
): SessionSummaryDetail | null {
  const stmt = db.prepare(`
    SELECT
      id,
      memory_session_id,
      content_session_id,
      project,
      user_prompt,
      request_summary,
      learned_summary,
      status,
      created_at,
      created_at_epoch
    FROM sdk_sessions
    WHERE id = ?
    LIMIT 1
  `);

  return (stmt.get(id) as SessionSummaryDetail | undefined) || null;
}