import {
  BadRequestException,
  Injectable,
  NotFoundException,
} from '@nestjs/common';
import { Prisma } from '@prisma/client';
import type {
  CreateTeamRequest,
  SetTeamMembersRequest,
  TeamDto,
  TeamMemberDto,
  TeamMemberRole,
  UpdateTeamRequest,
} from '@mento/shared';
import { PrismaService } from '../prisma/prisma.service';

@Injectable()
export class TeamsService {
  constructor(private readonly prisma: PrismaService) {}

  async list(organizationId: string): Promise<TeamDto[]> {
    const rows = await this.prisma.team.findMany({
      where: { organizationId },
      include: {
        members: {
          include: {
            user: {
              select: {
                id: true,
                fullName: true,
                avatarStorageKey: true,
              },
            },
          },
          orderBy: [{ role: 'asc' }, { user: { fullName: 'asc' } }],
        },
      },
      orderBy: { name: 'asc' },
    });
    return rows.map((row) => this.toDto(row));
  }

  async create(
    organizationId: string,
    dto: CreateTeamRequest,
  ): Promise<TeamDto> {
    const name = dto.name?.trim();
    if (!name) throw new BadRequestException('نام تیم الزامی است');

    const managerIds = new Set((dto.managerIds ?? []).filter(Boolean));
    const memberIds = [
      ...new Set([
        ...(dto.memberIds ?? []).filter(Boolean),
        ...managerIds,
      ]),
    ];

    if (memberIds.length) {
      await this.assertMembersInOrg(organizationId, memberIds);
    }

    try {
      const row = await this.prisma.team.create({
        data: {
          organizationId,
          name,
          description: dto.description?.trim() ?? '',
          members: memberIds.length
            ? {
                create: memberIds.map((userId) => ({
                  userId,
                  role: managerIds.has(userId) ? 'manager' : 'member',
                })),
              }
            : undefined,
        },
        include: {
          members: {
            include: {
              user: {
                select: {
                  id: true,
                  fullName: true,
                  avatarStorageKey: true,
                },
              },
            },
          },
        },
      });
      return this.toDto(row);
    } catch (e) {
      if (e instanceof Prisma.PrismaClientKnownRequestError && e.code === 'P2002') {
        throw new BadRequestException('تیمی با این نام از قبل وجود دارد');
      }
      throw e;
    }
  }

  async update(
    organizationId: string,
    id: string,
    dto: UpdateTeamRequest,
  ): Promise<TeamDto> {
    await this.ensureTeam(organizationId, id);
    const data: Prisma.TeamUpdateInput = {};
    if (dto.name !== undefined) {
      const name = dto.name.trim();
      if (!name) throw new BadRequestException('نام تیم الزامی است');
      data.name = name;
    }
    if (dto.description !== undefined) {
      data.description = dto.description.trim();
    }
    try {
      await this.prisma.team.update({ where: { id }, data });
    } catch (e) {
      if (e instanceof Prisma.PrismaClientKnownRequestError && e.code === 'P2002') {
        throw new BadRequestException('تیمی با این نام از قبل وجود دارد');
      }
      throw e;
    }
    return this.get(organizationId, id);
  }

  async remove(organizationId: string, id: string): Promise<void> {
    await this.ensureTeam(organizationId, id);
    await this.prisma.team.delete({ where: { id } });
  }

  async setMembers(
    organizationId: string,
    id: string,
    dto: SetTeamMembersRequest,
  ): Promise<TeamDto> {
    await this.ensureTeam(organizationId, id);
    const members = dto.members ?? [];
    const userIds = [...new Set(members.map((m) => m.userId).filter(Boolean))];
    if (userIds.length) {
      await this.assertMembersInOrg(organizationId, userIds);
    }

    const byUser = new Map<string, TeamMemberRole>();
    for (const m of members) {
      if (!m.userId) continue;
      byUser.set(m.userId, m.role === 'manager' ? 'manager' : 'member');
    }

    await this.prisma.$transaction([
      this.prisma.teamMember.deleteMany({ where: { teamId: id } }),
      ...(byUser.size
        ? [
            this.prisma.teamMember.createMany({
              data: [...byUser.entries()].map(([userId, role]) => ({
                teamId: id,
                userId,
                role,
              })),
            }),
          ]
        : []),
    ]);

    return this.get(organizationId, id);
  }

  private async get(organizationId: string, id: string): Promise<TeamDto> {
    const row = await this.prisma.team.findFirst({
      where: { id, organizationId },
      include: {
        members: {
          include: {
            user: {
              select: {
                id: true,
                fullName: true,
                avatarStorageKey: true,
              },
            },
          },
          orderBy: [{ role: 'asc' }, { user: { fullName: 'asc' } }],
        },
      },
    });
    if (!row) throw new NotFoundException('تیم پیدا نشد');
    return this.toDto(row);
  }

  private async ensureTeam(organizationId: string, id: string) {
    const row = await this.prisma.team.findFirst({
      where: { id, organizationId },
      select: { id: true },
    });
    if (!row) throw new NotFoundException('تیم پیدا نشد');
  }

  private async assertMembersInOrg(
    organizationId: string,
    userIds: string[],
  ) {
    const count = await this.prisma.membership.count({
      where: {
        organizationId,
        userId: { in: userIds },
        isActive: true,
      },
    });
    if (count !== userIds.length) {
      throw new BadRequestException('برخی کاربران عضو فعال این محیط نیستند');
    }
  }

  private toDto(row: {
    id: string;
    name: string;
    description: string;
    createdAt: Date;
    updatedAt: Date;
    members: Array<{
      role: string;
      user: {
        id: string;
        fullName: string;
        avatarStorageKey: string | null;
      };
    }>;
  }): TeamDto {
    const members: TeamMemberDto[] = row.members.map((m) => ({
      userId: m.user.id,
      fullName: m.user.fullName,
      role: m.role === 'manager' ? 'manager' : 'member',
      hasAvatar: Boolean(m.user.avatarStorageKey),
    }));
    return {
      id: row.id,
      name: row.name,
      description: row.description,
      memberCount: members.length,
      members,
      createdAt: row.createdAt.toISOString(),
      updatedAt: row.updatedAt.toISOString(),
    };
  }
}