import { FastifyInstance } from "fastify";
import crypto from "crypto";
import bcrypt from "bcryptjs";
import prisma from "../../config/database";
import { requireAuth, requirePermission } from "../../middleware/auth";
import { success, error } from "../../utils/response";
import { encrypt } from "../../utils/encryption";
import { getSystemSettings } from "../../services/system-settings";
import { OTPAuth } from "../../utils/totp";
import * as OTPAuthLib from "otpauth";
import { logAudit } from "../../services/audit";
import { parseBody } from "../../schemas/common";
import { TotpBackupSchema } from "../../schemas/auth.schema";

export default async function totpRoutes(
  fastify: FastifyInstance,
): Promise<void> {
  // GET - generate new TOTP secret
  fastify.get("/setup", { preHandler: requireAuth }, async (request, reply) => {
    const settings = await getSystemSettings();
    const companyName =
      (
        await prisma.company_settings.findFirst({
          select: { company_name: true },
        })
      )?.company_name ||
      settings.smtp_from_name ||
      "System";
    const secret = new OTPAuthLib.Secret();
    const totp = new OTPAuthLib.TOTP({
      issuer: companyName,
      label: request.authData!.email,
      secret,
      algorithm: "SHA1",
      digits: 6,
      period: 30,
    });

    return success(reply, {
      secret: secret.base32,
      uri: totp.toString(),
    });
  });

  // POST - enable TOTP
  fastify.post(
    "/enable",
    { preHandler: requireAuth, bodyLimit: 10240 },
    async (request, reply) => {
      const body = request.body as Record<string, unknown>;
      const { secret, code } = body;

      if (!secret || !code) {
        return error(reply, "Secret a kód jsou povinné", 400);
      }

      const totp = new OTPAuthLib.TOTP({
        secret: OTPAuthLib.Secret.fromBase32(String(secret)),
        algorithm: "SHA1",
        digits: 6,
        period: 30,
      });

      const delta = totp.validate({ token: String(code), window: 1 });
      if (delta === null) {
        return error(reply, "Neplatný TOTP kód", 400);
      }

      // Generate 8 backup codes
      const backupCodesPlain: string[] = [];
      const backupCodesHashed: string[] = [];
      for (let i = 0; i < 8; i++) {
        const code = crypto.randomBytes(4).toString("hex").toUpperCase();
        backupCodesPlain.push(code);
        backupCodesHashed.push(bcrypt.hashSync(code, 10));
      }

      const encryptedSecret = encrypt(String(secret));
      await prisma.users.update({
        where: { id: request.authData!.userId },
        data: {
          totp_secret: encryptedSecret,
          totp_enabled: true,
          totp_backup_codes: JSON.stringify(backupCodesHashed),
        },
      });

      await logAudit({
        request,
        authData: request.authData,
        action: "update",
        entityType: "user",
        entityId: request.authData!.userId,
        description: "2FA aktivováno",
      });
      return success(
        reply,
        { backup_codes: backupCodesPlain },
        200,
        "2FA aktivováno",
      );
    },
  );

  // PUT - disable TOTP
  fastify.put(
    "/disable",
    { preHandler: requireAuth },
    async (request, reply) => {
      const body = request.body as Record<string, unknown>;

      if (!body.code) {
        return error(reply, "TOTP kód je povinný pro deaktivaci", 400);
      }

      const user = await prisma.users.findUnique({
        where: { id: request.authData!.userId },
      });
      if (!user?.totp_secret) {
        return error(reply, "2FA není aktivní", 400);
      }

      const isValid = OTPAuth.verify(user.totp_secret, String(body.code));
      if (!isValid) {
        return error(reply, "Neplatný TOTP kód", 400);
      }

      await prisma.users.update({
        where: { id: request.authData!.userId },
        data: {
          totp_secret: null,
          totp_enabled: false,
          totp_backup_codes: null,
        },
      });

      await logAudit({
        request,
        authData: request.authData,
        action: "update",
        entityType: "user",
        entityId: request.authData!.userId,
        description: "2FA deaktivováno",
      });
      return success(reply, null, 200, "2FA deaktivováno");
    },
  );

  // GET - TOTP status for current user
  fastify.get(
    "/status",
    { preHandler: requireAuth },
    async (request, reply) => {
      const user = await prisma.users.findUnique({
        where: { id: request.authData!.userId },
        select: { totp_enabled: true },
      });

      return success(reply, { totp_enabled: user?.totp_enabled ?? false });
    },
  );

  // GET - check if 2FA is required company-wide
  fastify.get(
    "/required",
    { preHandler: [requireAuth, requirePermission("settings.manage")] },
    async (request, reply) => {
      const settings = await prisma.company_settings.findFirst({
        select: { require_2fa: true },
      });

      return success(reply, { require_2fa: settings?.require_2fa ?? false });
    },
  );

  // POST - toggle mandatory 2FA
  fastify.post(
    "/required",
    {
      preHandler: [requireAuth, requirePermission("settings.manage")],
      bodyLimit: 10240,
    },
    async (request, reply) => {
      const body = request.body as Record<string, unknown>;

      const required =
        body.required === true || body.required === 1 || body.required === "1";
      await prisma.company_settings.updateMany({
        data: { require_2fa: required },
      });

      const message = required
        ? "2FA je nyní povinné pro všechny uživatele"
        : "2FA již není povinné";

      return success(reply, null, 200, message);
    },
  );

  // POST - verify backup code (pre-auth, no requireAuth)
  fastify.post(
    "/backup-verify",
    { bodyLimit: 10240 },
    async (request, reply) => {
      const parsed = parseBody(TotpBackupSchema, request.body);
      if ("error" in parsed) return error(reply, parsed.error, 400);
      const { login_token, backup_code: code } = parsed.data;

      const tokenHash = crypto
        .createHash("sha256")
        .update(login_token)
        .digest("hex");

      const storedToken = await prisma.totp_login_tokens.findFirst({
        where: { token_hash: tokenHash },
      });

      if (!storedToken || new Date(storedToken.expires_at) < new Date()) {
        return error(reply, "Neplatný nebo expirovaný login token", 401);
      }

      const user = await prisma.users.findUnique({
        where: { id: storedToken.user_id },
        include: { roles: true },
      });

      if (!user || !user.totp_backup_codes) {
        return error(reply, "Uživatel nenalezen", 401);
      }

      const backupCodes: string[] = JSON.parse(
        user.totp_backup_codes as string,
      );
      let matchIndex = -1;

      for (let i = 0; i < backupCodes.length; i++) {
        const isMatch = await bcrypt.compare(String(code), backupCodes[i]);
        if (isMatch) {
          matchIndex = i;
          break;
        }
      }

      if (matchIndex === -1) {
        return error(reply, "Neplatný záložní kód", 401);
      }

      backupCodes.splice(matchIndex, 1);
      await prisma.users.update({
        where: { id: user.id },
        data: {
          totp_backup_codes: JSON.stringify(backupCodes),
          failed_login_attempts: 0,
          locked_until: null,
          last_login: new Date(),
        },
      });

      await prisma.totp_login_tokens.delete({ where: { id: storedToken.id } });

      // Create tokens (same as /login/totp flow)
      const { loadAuthData } = await import("../../services/auth");
      const authData = await loadAuthData(user.id);
      if (!authData) {
        return error(reply, "Chyba načítání uživatele", 500);
      }

      const jwt = await import("jsonwebtoken");
      const { config } = await import("../../config/env");

      const accessToken = jwt.default.sign(
        {
          sub: user.id,
          username: user.username,
          role: user.roles?.name ?? null,
        },
        config.jwt.secret,
        { expiresIn: config.jwt.accessTokenExpiry },
      );

      const refreshTokenRaw = crypto.randomBytes(32).toString("hex");
      const refreshTokenHash = crypto
        .createHash("sha256")
        .update(refreshTokenRaw)
        .digest("hex");

      await prisma.refresh_tokens.create({
        data: {
          user_id: user.id,
          token_hash: refreshTokenHash,
          expires_at: new Date(
            Date.now() + config.jwt.refreshTokenSessionExpiry * 1000,
          ),
          remember_me: false,
          ip_address: request.ip,
          user_agent: request.headers["user-agent"] ?? null,
        },
      });

      reply.setCookie("refresh_token", refreshTokenRaw, {
        httpOnly: true,
        secure: config.isProduction,
        sameSite: "strict",
        path: "/api/admin",
        maxAge: config.jwt.refreshTokenSessionExpiry,
      });

      return success(reply, { access_token: accessToken, user: authData });
    },
  );
}