import { Injectable, OnModuleDestroy } from '@nestjs/common';
import { PrismaPg } from '@prisma/adapter-pg';
import { PrismaClient } from '@prisma/client';
import { Pool } from 'pg';
import { requestContext } from '../common/request-context';

@Injectable()
export class PrismaService extends PrismaClient implements OnModuleDestroy {
  private readonly databasePool: Pool;
  private readonly databasePoolMax: number;

  constructor() {
    const processRole = process.env.CMPP_PROCESS_ROLE?.trim() || 'api';
    const workerRole = processRole === 'worker';
    const outboxRole = processRole === 'outbox';
    const callbackRole = processRole === 'callback';
    const protocolLogRole = processRole === 'protocol-log-worker';
    const databaseUrl = protocolLogRole
      ? process.env.API_PROTOCOL_LOG_DATABASE_URL || process.env.DATABASE_URL
      : outboxRole
      ? process.env.API_OUTBOX_DATABASE_URL || process.env.DATABASE_URL
      : callbackRole
        ? process.env.API_CALLBACK_DATABASE_URL || process.env.DATABASE_URL
        : workerRole
          ? process.env.API_WORKER_DATABASE_URL || process.env.DATABASE_URL
          : process.env.DATABASE_URL;
    const configuredPoolMax = Number(protocolLogRole
      ? process.env.API_PROTOCOL_LOG_DB_POOL_MAX ?? 4
      : outboxRole
      ? process.env.API_OUTBOX_DB_POOL_MAX ?? 6
      : callbackRole
        ? process.env.API_CALLBACK_DB_POOL_MAX ?? 16
        : workerRole
          ? process.env.API_WORKER_DB_POOL_MAX ?? 8
          : process.env.API_DB_POOL_MAX ?? 32);
    const poolMax = Number.isInteger(configuredPoolMax) && configuredPoolMax > 0
      ? configuredPoolMax
      : protocolLogRole ? 4 : outboxRole ? 6 : callbackRole ? 16 : workerRole ? 8 : 32;
    const allowDevelopmentDefault = process.env.NODE_ENV === 'development' || process.env.NODE_ENV === 'test';
    if (!databaseUrl && !allowDevelopmentDefault) {
      throw new Error(`DATABASE_URL is required for CMPP process role ${processRole}`);
    }
    const databasePool = new Pool({
      connectionString: databaseUrl
        ?? 'postgresql://cmpp:cmpp_password@localhost:5432/cmpp_platform?schema=public',
      // API capacity must be reserved independently from the heavier Worker
      // transactions; explicit bounds also protect PostgreSQL max_connections.
      max: poolMax,
    });
    super({ adapter: new PrismaPg(databasePool, { disposeExternalPool: true }) });
    this.databasePool = databasePool;
    this.databasePoolMax = poolMax;
    const operationLog = this.operationLog;
    Object.defineProperty(this, 'operationLog', {
      value: new Proxy(operationLog, {
        get(target, property, receiver) {
          if (property === 'create') {
            return (args: { data: Record<string, unknown> }) => {
              const ipAddress = requestContext.getStore()?.ipAddress;
              return (target.create as (input: unknown) => unknown)({
                ...args,
                data: { ...args.data, ipAddress: typeof args.data.ipAddress === 'string' ? args.data.ipAddress : ipAddress },
              });
            };
          }
          const value = Reflect.get(target, property, receiver);
          return typeof value === 'function' ? value.bind(target) : value;
        },
      }),
      configurable: true,
    });
  }

  getPoolState() {
    return {
      max: this.databasePoolMax,
      total: this.databasePool.totalCount,
      idle: this.databasePool.idleCount,
      waiting: this.databasePool.waitingCount,
    };
  }

  async onModuleDestroy() {
    await this.$disconnect();
  }
}