import {
  ConflictException,
  ForbiddenException,
  Injectable,
  NotFoundException,
  UnauthorizedException,
} from '@nestjs/common';
import { ConfigService } from '@nestjs/config';
import { Role, SyncOperation } from '@prisma/client';
import * as bcrypt from 'bcryptjs';
import * as jwt from 'jsonwebtoken';
import { PrismaClient } from '../prisma/prisma.module';
import { SyncService } from '../sync/sync.service';
import { AuthenticatedUser } from './authenticated-request';
import { toAuthenticatedUser } from './provision-user';

export interface TeamJwtPayload {
  sub: string;
  typ: 'team';
}

const TOKEN_TTL = '12h';
const BCRYPT_ROUNDS = 10;

/// Local (non-Authentik) auth for Gemeinde Teamer: password login plus
/// redemption of a TeamerInvite issued by a Gemeinde Verantwortliche/r. Team
/// tokens are signed with TEAM_JWT_SECRET and carry `typ: 'team'` so they are
/// never mistaken for a guest token.
@Injectable()
export class TeamAuthService {
  private readonly secret: string;

  constructor(
    private readonly prisma: PrismaClient,
    private readonly config: ConfigService,
    private readonly sync: SyncService,
  ) {
    this.secret = config.getOrThrow<string>('TEAM_JWT_SECRET');
  }

  /// Logs a Teamer in by email (legacy) OR by Gemeinde name — the normal
  /// path, since a Teamer thinks of their login as "meine Gemeinde" rather
  /// than an email address. A Gemeinde can have several Teamer accounts, so
  /// a name lookup tries the password against every active GEMEINDE_TEAMER
  /// membership for that Gemeinde (case-insensitive, trimmed name) until one
  /// matches, rather than assuming a 1:1 Gemeinde-to-account mapping.
  async login(
    credentials: { email?: string; gemeindeName?: string },
    password: string,
  ): Promise<{ accessToken: string }> {
    if (credentials.email) {
      const user = await this.prisma.user.findUnique({
        where: { email: credentials.email.toLowerCase() },
      });
      if (!user || !user.passwordHash || !(await bcrypt.compare(password, user.passwordHash))) {
        throw new UnauthorizedException('Invalid credentials');
      }
      return { accessToken: this.sign(user.id) };
    }

    const gemeindeName = credentials.gemeindeName?.trim();
    if (!gemeindeName) {
      throw new UnauthorizedException('Invalid credentials');
    }
    const memberships = await this.prisma.membership.findMany({
      where: {
        role: Role.GEMEINDE_TEAMER,
        status: 'ACTIVE',
        gemeinde: { name: { equals: gemeindeName, mode: 'insensitive' } },
      },
      include: { user: true },
    });
    for (const m of memberships) {
      if (m.user.passwordHash && (await bcrypt.compare(password, m.user.passwordHash))) {
        return { accessToken: this.sign(m.user.id) };
      }
    }
    throw new UnauthorizedException('Invalid credentials');
  }

  /// Redeems an invite token and creates the local Teamer account + its
  /// GEMEINDE_TEAMER membership for the invite's Gemeinde.
  async registerFromInvite(input: {
    token: string;
    firstName: string;
    lastName: string;
    password: string;
    email?: string;
  }): Promise<{ accessToken: string }> {
    const invite = await this.prisma.teamerInvite.findUnique({
      where: { token: input.token },
    });
    if (!invite || invite.revokedAt) {
      throw new NotFoundException('Unknown or revoked invite');
    }
    if (invite.expiresAt && invite.expiresAt.getTime() < Date.now()) {
      throw new ForbiddenException('Invite has expired');
    }
    if (invite.maxUses !== null && invite.usedCount >= invite.maxUses) {
      throw new ForbiddenException('Invite has already been used up');
    }

    if (
      invite.email &&
      input.email &&
      input.email.toLowerCase() !== invite.email.toLowerCase()
    ) {
      throw new ForbiddenException('Email does not match this invite');
    }
    const email = (invite.email ?? input.email ?? '').toLowerCase();
    if (!email) {
      throw new ConflictException('This invite requires an email address');
    }
    if (await this.prisma.user.findUnique({ where: { email } })) {
      throw new ConflictException('An account with this email already exists');
    }

    const passwordHash = await bcrypt.hash(input.password, BCRYPT_ROUNDS);
    const user = await this.prisma.user.create({
      data: {
        email,
        firstName: input.firstName,
        lastName: input.lastName,
        passwordHash,
        kcId: invite.kcId,
      },
    });
    const membership = await this.prisma.membership.create({
      data: {
        userId: user.id,
        kcId: invite.kcId,
        gemeindeId: invite.gemeindeId,
        role: Role.GEMEINDE_TEAMER,
      },
    });
    const updatedInvite = await this.prisma.teamerInvite.update({
      where: { id: invite.id },
      data: { usedCount: { increment: 1 } },
    });

    await this.sync.capture('User', SyncOperation.CREATE, user.id, user);
    await this.sync.capture('Membership', SyncOperation.CREATE, membership.id, membership);
    await this.sync.capture('TeamerInvite', SyncOperation.UPDATE, updatedInvite.id, updatedInvite);

    return { accessToken: this.sign(user.id) };
  }

  private sign(userId: string): string {
    const payload: TeamJwtPayload = { sub: userId, typ: 'team' };
    return jwt.sign(payload, this.secret, { expiresIn: TOKEN_TTL });
  }

  /// Verifies a raw team token (used by the WS handshake path, outside passport).
  async verify(token: string): Promise<AuthenticatedUser> {
    let payload: TeamJwtPayload;
    try {
      payload = jwt.verify(token, this.secret) as TeamJwtPayload;
    } catch {
      throw new UnauthorizedException('Invalid team token');
    }
    if (payload.typ !== 'team' || !payload.sub) {
      throw new UnauthorizedException('Not a team token');
    }
    return this.resolve(payload.sub);
  }

  async resolve(userId: string): Promise<AuthenticatedUser> {
    const user = await this.prisma.user.findFirst({
      where: { id: userId, passwordHash: { not: null } },
      include: { memberships: { where: { status: 'ACTIVE' } } },
    });
    if (!user) {
      throw new UnauthorizedException('Team account no longer exists');
    }
    // Same shape as the Authentik path, incl. the synthetic global
    // LEITUNGSTEAM membership when `isLeitungsteam` is set on the row.
    return toAuthenticatedUser(user);
  }
}