/** 会话与消息的读写（A3.7）。只碰平台库，不涉及业务数据（ADR-0008）。 */
import type { ChatMessage, SessionSummary } from '@aps/contracts';

import type { Database } from './db.js';

export interface StoredSession extends SessionSummary {
  owner: { userId: string; tenantId: string; displayName: string; clientKind: 'desktop' | 'browser' };
}

interface SessionRow {
  session_id: string;
  project_id: string | null;
  scope: string;
  status: string;
  title: string;
  owner_user_id: string;
  owner_tenant_id: string;
  owner_display_name: string;
  owner_client_kind: string;
  created_at: number;
}

interface MessageRow {
  message_id: string;
  session_id: string;
  role: string;
  text: string;
  ts: number;
}

const toSession = (row: SessionRow): StoredSession => ({
  sessionId: row.session_id,
  projectId: row.project_id,
  scope: row.scope as SessionSummary['scope'],
  status: row.status as SessionSummary['status'],
  title: row.title,
  createdAt: row.created_at,
  owner: {
    userId: row.owner_user_id,
    tenantId: row.owner_tenant_id,
    displayName: row.owner_display_name,
    clientKind: row.owner_client_kind as 'desktop' | 'browser',
  },
});

const toMessage = (row: MessageRow): ChatMessage => ({
  messageId: row.message_id,
  role: row.role as ChatMessage['role'],
  ts: row.ts,
  text: row.text,
});

export class SessionRepository {
  constructor(private readonly db: Database) {}

  insertSession(session: StoredSession): void {
    this.db
      .prepare(
        'insert into sessions (session_id, project_id, scope, status, title, owner_user_id, owner_tenant_id, owner_display_name, owner_client_kind, created_at) values (?, ?, ?, ?, ?, ?, ?, ?, ?, ?)',
      )
      .run(
        session.sessionId,
        session.projectId,
        session.scope,
        session.status,
        session.title,
        session.owner.userId,
        session.owner.tenantId,
        session.owner.displayName,
        session.owner.clientKind,
        session.createdAt,
      );
  }

  getSession(sessionId: string): StoredSession | undefined {
    const row = this.db.prepare('select * from sessions where session_id = ?').get(sessionId) as unknown as SessionRow | undefined;
    return row ? toSession(row) : undefined;
  }

  listSessions(projectId?: string): StoredSession[] {
    const rows = (
      projectId === undefined
        ? this.db.prepare('select * from sessions order by created_at desc').all()
        : this.db.prepare('select * from sessions where project_id = ? order by created_at desc').all(projectId)
    ) as unknown as SessionRow[];
    return rows.map(toSession);
  }

  appendMessage(sessionId: string, message: ChatMessage): void {
    this.db
      .prepare('insert into messages (message_id, session_id, role, text, ts) values (?, ?, ?, ?, ?)')
      .run(message.messageId, sessionId, message.role, message.text, message.ts);
  }

  listMessages(sessionId: string): ChatMessage[] {
    const rows = this.db
      .prepare('select * from messages where session_id = ? order by ts asc, rowid asc')
      .all(sessionId) as unknown as MessageRow[];
    return rows.map(toMessage);
  }

  rememberIdempotencyKey(key: string, sessionId: string, messageId: string, runId: string): void {
    this.db
      .prepare(
        'insert or ignore into idempotency_keys (idempotency_key, session_id, message_id, run_id, created_at) values (?, ?, ?, ?, ?)',
      )
      .run(key, sessionId, messageId, runId, Date.now());
  }

  findByIdempotencyKey(key: string): { sessionId: string; messageId: string; runId: string } | undefined {
    const row = this.db.prepare('select session_id, message_id, run_id from idempotency_keys where idempotency_key = ?').get(key) as
      | { session_id: string; message_id: string; run_id: string }
      | undefined;
    return row ? { sessionId: row.session_id, messageId: row.message_id, runId: row.run_id } : undefined;
  }
}