import { getPool } from "./database";
import { UserProfile } from "../lib/types";

export class UserService {
  /**
   * Crée ou met à jour un utilisateur et retourne son UUID
   */
  async upsertUserUuid(profile: UserProfile): Promise<string> {
    const pool = getPool();
    const client = await pool.connect();

    try {
      // Créer un nouvel utilisateur avec UUID auto-généré
      const insertQuery = `
        INSERT INTO users (first_name, last_name, team_id, uuid_id)
        VALUES ($1, $2, $3, uuid_generate_v4())
        RETURNING uuid_id
      `;

      const result = await client.query(insertQuery, [
        profile.firstName,
        profile.lastName,
        profile.teamId,
      ]);

      return result.rows[0].uuid_id;
    } catch (error: any) {
      // Si erreur de contrainte unique, l'utilisateur existe déjà
      if (
        error.code === "23505" &&
        error.constraint === "users_first_name_last_name_team_id_key"
      ) {
        // Récupérer l'utilisateur existant
        const existingUserQuery = `
          SELECT uuid_id FROM users 
          WHERE first_name = $1 AND last_name = $2 AND team_id = $3
        `;

        const existingUser = await client.query(existingUserQuery, [
          profile.firstName,
          profile.lastName,
          profile.teamId,
        ]);

        return existingUser.rows[0].uuid_id;
      }
      throw error;
    } finally {
      client.release();
    }
  }

  /**
   * Met à jour un utilisateur existant par son UUID
   */
  async updateUserByUuid(
    userUuid: string,
    profile: UserProfile
  ): Promise<void> {
    const pool = getPool();
    const client = await pool.connect();

    try {
      // Vérifier s'il existe déjà un utilisateur avec ce nom/prénom dans la nouvelle équipe
      const conflictCheckQuery = `
        SELECT uuid_id FROM users 
        WHERE first_name = $1 AND last_name = $2 AND team_id = $3 AND uuid_id != $4
      `;

      const conflictResult = await client.query(conflictCheckQuery, [
        profile.firstName,
        profile.lastName,
        profile.teamId,
        userUuid,
      ]);

      if (conflictResult.rows.length > 0) {
        throw new Error(
          "Un utilisateur avec ce nom et prénom existe déjà dans cette équipe"
        );
      }

      // Mettre à jour l'utilisateur existant
      const updateQuery = `
        UPDATE users 
        SET first_name = $1, last_name = $2, team_id = $3, updated_at = CURRENT_TIMESTAMP
        WHERE uuid_id = $4
      `;

      await client.query(updateQuery, [
        profile.firstName,
        profile.lastName,
        profile.teamId,
        userUuid,
      ]);
    } finally {
      client.release();
    }
  }

  /**
   * Récupère un utilisateur par son UUID
   */
  /**
   * Trouve un utilisateur par son profil (firstName, lastName)
   */
  async findUserByProfile(profile: UserProfile): Promise<{
    uuid: string;
    teamId: string;
  } | null> {
    const pool = getPool();
    const client = await pool.connect();

    try {
      const query = `
        SELECT uuid_id, team_id
        FROM users
        WHERE first_name = $1 AND last_name = $2
      `;

      const result = await client.query(query, [
        profile.firstName,
        profile.lastName,
      ]);

      if (result.rows.length === 0) {
        return null;
      }

      return {
        uuid: result.rows[0].uuid_id,
        teamId: result.rows[0].team_id,
      };
    } finally {
      client.release();
    }
  }

  async getUserByUuid(userUuid: string): Promise<UserProfile | null> {
    const pool = getPool();
    const client = await pool.connect();

    try {
      const query = `
        SELECT u.first_name, u.last_name, u.team_id
        FROM users u
        WHERE u.uuid_id = $1
      `;

      const result = await client.query(query, [userUuid]);

      if (result.rows.length === 0) {
        return null;
      }

      const user = result.rows[0];
      return {
        firstName: user.first_name,
        lastName: user.last_name,
        teamId: user.team_id,
      };
    } finally {
      client.release();
    }
  }

  /**
   * Crée ou met à jour un utilisateur (legacy - retourne l'ID numérique)
   */
  async upsertUser(profile: UserProfile): Promise<number> {
    const pool = getPool();
    const client = await pool.connect();

    try {
      // Vérifier si l'utilisateur existe déjà (par firstName + lastName + teamId)
      const existingUserQuery = `
        SELECT id FROM users 
        WHERE first_name = $1 AND last_name = $2 AND team_id = $3
      `;

      const existingUser = await client.query(existingUserQuery, [
        profile.firstName,
        profile.lastName,
        profile.teamId,
      ]);

      if (existingUser.rows.length > 0) {
        // Mettre à jour l'utilisateur existant
        const updateQuery = `
          UPDATE users 
          SET first_name = $1, last_name = $2, team_id = $3, updated_at = CURRENT_TIMESTAMP
          WHERE id = $4
          RETURNING id
        `;

        const result = await client.query(updateQuery, [
          profile.firstName,
          profile.lastName,
          profile.teamId,
          existingUser.rows[0].id,
        ]);

        return result.rows[0].id;
      } else {
        // Créer un nouvel utilisateur
        const insertQuery = `
          INSERT INTO users (first_name, last_name, team_id)
          VALUES ($1, $2, $3)
          RETURNING id
        `;

        const result = await client.query(insertQuery, [
          profile.firstName,
          profile.lastName,
          profile.teamId,
        ]);

        return result.rows[0].id;
      }
    } finally {
      client.release();
    }
  }

  /**
   * Delete user for admin
   */
  static async deleteUserForAdmin(
    userId: string
  ): Promise<{ firstName: string; lastName: string }> {
    const pool = getPool();
    const client = await pool.connect();

    try {
      await client.query("BEGIN");

      // Vérifier que l'utilisateur existe
      const userCheck = await client.query(
        "SELECT uuid_id, first_name, last_name, team_id FROM users WHERE uuid_id = $1",
        [userId]
      );

      if (userCheck.rows.length === 0) {
        throw new Error("Utilisateur non trouvé");
      }

      const user = userCheck.rows[0];

      // Vérifier que l'utilisateur n'est pas dans une équipe
      if (user.team_id) {
        throw new Error(
          "Impossible de supprimer un utilisateur qui appartient à une équipe. Retirez-le d'abord de son équipe."
        );
      }

      // Supprimer l'utilisateur (les évaluations par skills seront supprimées automatiquement grâce aux contraintes CASCADE)
      await client.query("DELETE FROM users WHERE uuid_id = $1", [userId]);

      await client.query("COMMIT");

      return {
        firstName: user.first_name,
        lastName: user.last_name,
      };
    } catch (error) {
      await client.query("ROLLBACK");
      throw error;
    } finally {
      client.release();
    }
  }

  /**
   * Get all users with team info and evaluations status for admin
   */
  static async getAllUsersForAdmin(): Promise<
    Array<{
      uuid: string;
      firstName: string;
      lastName: string;
      teamName: string | null;
      hasEvaluations: boolean;
    }>
  > {
    const pool = getPool();
    const query = `
      SELECT 
        u.uuid_id,
        u.first_name,
        u.last_name,
        t.name as team_name,
        CASE 
          WHEN ue.id IS NOT NULL THEN true 
          ELSE false 
        END as has_evaluations
      FROM users u
      LEFT JOIN teams t ON u.team_id = t.id
      LEFT JOIN user_evaluations ue ON u.uuid_id = ue.user_uuid
      ORDER BY u.first_name, u.last_name
    `;

    try {
      const result = await pool.query(query);

      return result.rows.map((row) => ({
        uuid: row.uuid_id,
        firstName: row.first_name,
        lastName: row.last_name,
        teamName: row.team_name,
        hasEvaluations: row.has_evaluations,
      }));
    } catch (error) {
      console.error("Error fetching users:", error);
      throw new Error("Failed to fetch users");
    }
  }
}

// Instance singleton
export const userService = new UserService();