main.cpp

// ============================================================
//  main.cpp  --  Freelance Marketplace System
//  Entry point: main menu, registration, login
//
//  Compile:
//    g++ -std=c++11 -o marketplace main.cpp
//
//  100% C++11:
//    string (not char[])  |  nullptr (not NULL)
//    stod / stoi          |  getline (not scanf)
//    vector<>             |  auto keyword
//    RAII file streams    |  range-based for loops
//
//  Compatible: VS Code, Dev C++, Code::Blocks
// ============================================================

#include <iostream>
#include <string>
#include "utils.h"
#include "FileManager.h"
#include "User.h"
#include "Freelancer.h"
#include "Client.h"
#include "Admin.h"
#include "Exceptions.h"
using namespace std;

// Global FileManager used during registration and login
FileManager gFM;

// Forward declarations
void showMainMenu();
void handleRegister();
void handleLogin();
void registerAsFreelancer(const string& uid, const string& uname);
void registerAsClient(const string& uid, const string& uname);




// ============================================================
//  ENTRY POINT
// ============================================================
int main() {
    try {
        showMainMenu();
    }
    catch (const FileException& e) {
        cerr << "\n[FILE ERROR] " << e.what() << endl;
    }
    catch (const ValidationException& e) {
        cerr << "\n[VALIDATION ERROR] " << e.what() << endl;
    }
    catch (const AuthenticationException& e) {
        cerr << "\n[AUTH ERROR] " << e.what() << endl;
    }
    catch (const exception& e) {
        cerr << "\n[UNEXPECTED ERROR] " << e.what() << endl;
    }
    return 0;
}

// ============================================================
//  MAIN MENU
// ============================================================
void showMainMenu() {
    while (true) {
        clearScreen();
        cout << "\n\n"
             << "  +============================================+\n"
             << "  |                                            |\n"
             << "  |      FREELANCE MARKETPLACE SYSTEM          |\n"
             << "  |         Console-Based Edition  (C++)       |\n"
             << "  |                                            |\n"
             << "  +============================================+\n\n"
             << "  [1] Register New Account\n"
             << "  [2] Login\n"
             << "  [3] Exit\n\n";

        int choice = getChoice(1, 3);
        switch (choice) {
            case 1: handleRegister(); break;
            case 2: handleLogin();    break;
            case 3:
                clearScreen();
                cout << "\n  Thank you for using Freelance Marketplace!\n\n";
                return;
        }
    }
}

// ============================================================
//  REGISTRATION
// ============================================================
void handleRegister() {
    clearScreen();
    printHeader("CREATE NEW ACCOUNT");

    cout << "  Select Account Type:\n\n"
         << "  [1] Freelancer  (I offer services)\n"
         << "  [2] Client      (I post projects)\n"
         << "  [3] Back\n\n";

    int typeChoice = getChoice(1, 3);
    if (typeChoice == 3) return;

    // ---- Common registration fields ----
    cout << "\n  Username: ";
    string username;
    getline(cin, username);
        if(username.empty()) throw ValidationException("Username cannot be empty");
    if (username.empty()) {
        cout << "  Username cannot be empty.\n";
        pressEnterToContinue();
        return;
    }
    if (gFM.usernameExists(username)) {
        cout << "  Username '" << username << "' is already taken.\n";
        pressEnterToContinue();
        return;
    }

    cout << "  Password (min 6 chars): ";
    string password;
    getline(cin, password);
    if (password.length() < 6) {
        cout << "  Password must be at least 6 characters.\n";
        pressEnterToContinue();
        return;
    }

    cout << "  Email: ";
    string email;
    getline(cin, email);
    if (email.empty() || email.find('@') == string::npos) {
        cout << "  Please enter a valid email address.\n";
        pressEnterToContinue();
        return;
    }

    string uid  = generateID("U", FileManager::getUsersFile());
    string type = (typeChoice == 1) ? "Freelancer" : "Client";
    gFM.saveUser(uid, username, password, email, type);

    if (typeChoice == 1)
        registerAsFreelancer(uid, username);
    else
        registerAsClient(uid, username);
}

// Collect extra Freelancer info after basic account is created
void registerAsFreelancer(const string& uid, const string& uname) {
    cout << "\n  Your Skills (e.g. C++ Python Web): ";
    string skills;
    getline(cin, skills);
    if (skills.empty()) skills = "General";

    double rate = getDouble("  Hourly Rate (Rs.): ");

    gFM.saveFreelancerProfile(uname, skills, rate);

    cout << "\n  ==========================================\n"
         << "  Account created successfully!\n"
         << "  User ID  : " << uid    << "\n"
         << "  Username : " << uname  << "\n"
         << "  Type     : Freelancer\n"
         << "  Skills   : " << skills << "\n"
         << "  ==========================================\n";
    pressEnterToContinue();
}

// Collect extra Client info after basic account is created
void registerAsClient(const string& uid, const string& uname) {
    cout << "\n  Company Name (press Enter to skip): ";
    string company;
    getline(cin, company);

    cout << "\n  ==========================================\n"
         << "  Account created successfully!\n"
         << "  User ID  : " << uid   << "\n"
         << "  Username : " << uname << "\n"
         << "  Type     : Client\n";
    if (!company.empty())
        cout << "  Company  : " << company << "\n";
    cout << "  ==========================================\n";
    pressEnterToContinue();
}

// ============================================================
//  LOGIN  --  demonstrates RUNTIME POLYMORPHISM
// ============================================================
void handleLogin() {
    clearScreen();
    printHeader("LOGIN");

    cout << "  Username: ";
    string username;
    getline(cin, username);

    cout << "  Password: ";
    string password;
    getline(cin, password);

    // loginUser now returns userType and fills outUserID + outEmail
    string outUserID, outEmail;
    string userType = gFM.loginUser(username, password, outUserID, outEmail);

    if (userType.empty()) {
        cout << "\n  Incorrect username or password. Please try again.\n";
        pressEnterToContinue();
        return;
    }

    cout << "\n  Login successful! Welcome, " << username << "!\n";

    // ================================================================
    //  POLYMORPHISM in action
    //
    //  'currentUser' is declared as User* (base-class pointer).
    //  But it actually POINTS TO a derived object:
    //    Freelancer  OR  Client  OR  Admin
    //
    //  When displayDashboard() is called on it:
    //    - C++ looks up the virtual function table (vtable)
    //    - Calls the CORRECT overridden version at RUNTIME
    //
    //  This means one line of code handles 3 different dashboards.
    //  Adding a new user type (e.g. Moderator) would need only:
    //    1. A new class inheriting User
    //    2. One more 'else if' below
    //  Nothing else changes.
    //
    //  'nullptr' is C++ (replaces C's NULL).
    // ================================================================
    User* currentUser = nullptr;

    if (userType == "Freelancer")
        currentUser = new Freelancer(outUserID, username, password, outEmail);
    else if (userType == "Client")
        currentUser = new Client(outUserID, username, password, outEmail, "");
    else if (userType == "Admin")
        currentUser = new Admin(outUserID, username, password, outEmail);

    if (currentUser != nullptr) {
        currentUser->displayDashboard();  // virtual dispatch
        delete currentUser;               // calls virtual destructor
        currentUser = nullptr;
    }
}