import {
  Body,
  ConflictException,
  Controller,
  DefaultValuePipe,
  ForbiddenException,
  Get,
  Headers,
  HttpException,
  NotFoundException,
  Param,
  ParseIntPipe,
  Patch,
  Post,
  Query,
  Req,
} from '@nestjs/common';
import { InjectRepository } from '@nestjs/typeorm';
import { Repository } from 'typeorm';
import * as bcrypt from 'bcryptjs';
import { randomBytes } from 'crypto';
import { GuildNode } from '../entities/guild-node.entity';
import { AuditService } from '../audit/audit.service';
import { RegisterNodeDto } from './dto.register-node.dto';
import { UpdateNodeStatusDto } from './dto.update-node-status.dto';
import { FABRIC_PROTOCOL_VERSION, normalizeVersion } from '../common/version';

@Controller('nodes')
export class NodesController {
  constructor(
    @InjectRepository(GuildNode)
    private readonly nodeRepo: Repository<GuildNode>,
    private readonly audit: AuditService,
  ) {}

  @Post('register')
  async register(
    @Req() req: { ip?: string; socket?: { remoteAddress?: string } },
    @Body() body: RegisterNodeDto,
    @Headers('x-fabric-version') fabricVersion?: string,
  ) {
    const remoteAddress = (req.ip ?? req.socket?.remoteAddress ?? '').toLowerCase();
    const isLoopback =
      remoteAddress === '127.0.0.1' ||
      remoteAddress === '::1' ||
      remoteAddress === '::ffff:127.0.0.1';
    if (!isLoopback) {
      throw new ForbiddenException('register endpoint only allows localhost caller');
    }

    const requestedVersion = normalizeVersion(fabricVersion);
    if (requestedVersion !== FABRIC_PROTOCOL_VERSION) {
      throw new HttpException(
        {
          error: {
            code: 'FABRIC_VERSION_NOT_SUPPORTED',
            message: `unsupported protocol version: ${requestedVersion}`,
            retryable: false,
          },
          supportedVersion: FABRIC_PROTOCOL_VERSION,
        },
        400,
      );
    }

    const existedByNodeId = await this.nodeRepo.findOne({
      where: { nodeId: body.nodeId },
    });
    if (existedByNodeId) {
      throw new ConflictException('nodeId already exists');
    }

    const existedByEndpoint = await this.nodeRepo.findOne({
      where: { endpoint: body.endpoint },
    });
    if (existedByEndpoint) {
      throw new ConflictException('endpoint already exists');
    }

    const node = this.nodeRepo.create({
      nodeId: body.nodeId,
      name: body.name,
      endpoint: body.endpoint,
      status: 'active',
      apiKeyHash: null,
    });
    const rawApiKey = `gk_${randomBytes(24).toString('hex')}`;
    node.apiKeyHash = await bcrypt.hash(rawApiKey, 10);
    const saved = await this.nodeRepo.save(node);
    await this.audit.write({
      action: 'node.register',
      targetType: 'node',
      targetId: saved.nodeId,
      detail: JSON.stringify({ endpoint: saved.endpoint }),
    });

    return {
      status: 'accepted',
      negotiatedVersion: FABRIC_PROTOCOL_VERSION,
      node: {
        id: saved.id,
        nodeId: saved.nodeId,
        name: saved.name,
        endpoint: saved.endpoint,
        status: saved.status,
      },
      apiKey: rawApiKey,
    };
  }

  @Post(':nodeId/heartbeat')
  async heartbeat(@Param('nodeId') nodeId: string) {
    const node = await this.nodeRepo.findOne({ where: { nodeId } });
    if (!node) {
      throw new NotFoundException('node not found');
    }

    node.lastHeartbeatAt = new Date();
    if (node.status !== 'revoked') {
      node.status = 'active';
    }

    const saved = await this.nodeRepo.save(node);
    await this.audit.write({
      action: 'node.heartbeat',
      targetType: 'node',
      targetId: saved.nodeId,
      detail: JSON.stringify({ status: saved.status }),
    });
    return {
      status: 'ok',
      nodeId: saved.nodeId,
      nodeStatus: saved.status,
      lastHeartbeatAt: saved.lastHeartbeatAt,
    };
  }

  @Patch(':nodeId/status')
  async updateStatus(
    @Param('nodeId') nodeId: string,
    @Body() body: UpdateNodeStatusDto,
  ) {
    const node = await this.nodeRepo.findOne({ where: { nodeId } });
    if (!node) {
      throw new NotFoundException('node not found');
    }

    node.status = body.status;
    const saved = await this.nodeRepo.save(node);
    await this.audit.write({
      action: 'node.status.update',
      targetType: 'node',
      targetId: saved.nodeId,
      detail: JSON.stringify({ status: saved.status }),
    });
    return {
      id: saved.id,
      nodeId: saved.nodeId,
      name: saved.name,
      endpoint: saved.endpoint,
      status: saved.status,
    };
  }

  @Get()
  async list(
    @Query('page', new DefaultValuePipe(1), ParseIntPipe) page: number,
    @Query('pageSize', new DefaultValuePipe(20), ParseIntPipe) pageSize: number,
  ) {
    const safePage = page < 1 ? 1 : page;
    const safePageSize = pageSize < 1 ? 20 : Math.min(pageSize, 100);

    const [items, total] = await this.nodeRepo.findAndCount({
      order: { createdAt: 'DESC' },
      skip: (safePage - 1) * safePageSize,
      take: safePageSize,
    });

    return {
      items,
      page: safePage,
      pageSize: safePageSize,
      total,
      totalPages: Math.max(1, Math.ceil(total / safePageSize)),
    };
  }
}