#include "Patient.hpp"
#include <algorithm>
#include <fstream>
#include <functional>
#include <iostream>
#include <optional>
#include <sstream>
#include <sys/types.h>

#ifndef CLINIC_
#define CLINIC_

enum class MenuChoice {
  NewPatient = 1,
  NewVisit = 2,
  DisplayPatient = 3,
  Quit = 4,
};

struct Clinic {
public:
  std::vector<Patient> patients;
  std::string filename;

private:
  // C++ types are getting crazy here :( I really miss Rust
  // `std::optional` needed because a patient might not be found
  // `std::reference_wrapper` because `std::optional` deoesn't accept references
  // I want to reference because (I want to save cpu cycles from memory copies)
  std::optional<std::reference_wrapper<Patient>>
  find_patient(u_int32_t patient_id) {
    auto it = std::find_if(patients.begin(), patients.end(),
                           [&id = patient_id](const Patient &p) -> bool {
                             return p.get_id() == id;
                           });
    if (it != patients.end())
      return *it;
    return std::nullopt;
  };

public:
  Clinic(std::string filename) : filename(filename) {
    ///  this file contains a list of patient IDs.
    // 1
    // 2
    // 4  (could be non-sequential
    //     but always sorted!)
    u_int32_t patient_id;
    std::ifstream file{filename};
    if (!file.is_open()) {
      std::cerr << "File " << filename << " couldn't be opened :(\n";
      exit(1);
    }

    while (file >> patient_id)
      patients.push_back(Patient(patient_id));
  }

  // writes the patients.txt file containing patient IDs.
  void write_file() {
    std::ofstream file{filename};
    for (auto p : patients)
      file << p.get_id() << "\n";
  }
  u_int32_t generate_id() {
    u_int32_t id{};
    // O(n), could be improved by using UUIDs, or store max_id in Clinic
    for (auto p : patients)
      id = std::max(id, p.get_id());
    id++;
    return id;
  }

  MenuChoice menu_main() {
    int choice{};
    std::cout << "==============================================\n";
    std::cout << "Please choose a command:\n";
    std::cout << "1. add new patient\n";
    std::cout << "2. add new visit\n";
    std::cout << "3. display patient information\n";
    std::cout << "4. quit\n";
    std::cout << ">> ";

    std::cin >> choice;

    while (choice < int(MenuChoice::NewPatient) ||
           choice > int(MenuChoice::Quit)) {
      std::cout << "Invalid input! Try again :)\n";
      std::cout << "Please choose a command:\n";
      std::cout << "1. add new patient\n";
      std::cout << "2. add new visit\n";
      std::cout << "3. display patient information\n";
      std::cout << "4. quit\n";
      std::cout << ">> ";
      std::cin >> choice;
    }
    return static_cast<MenuChoice>(choice);
  }

  void menu_patient_info() {
    int patient_id;
    std::cout << "Patient file number: ";
    std::cin >> patient_id;
    auto patient = find_patient(patient_id);
    if (patient.has_value())
      std::cout << patient.value();
    else
      std::cout << "No Patient exists with id= " << patient_id << "\n";
    std::cout << "--------------------\n\n";
  }

  void menu_add_new_patient() {
    std::string reading_string;
    std::string input_string;
    Patient patient{};
    std::stringstream patient_stream;

    // not the most optimal way, but the lazy way
    // see: https://ammar.engineer/posts/2023/06/03/laziness/
    // this "emulates" a file so that I can resuse my >> operator
    reading_string += std::to_string(generate_id()) + "\n";
    std::cout << "Generate " << reading_string;
    std::cout << "First name (no spaces): ";
    std::cin >> input_string;
    reading_string += input_string + "\n";
    std::cout << "Last name (no spaces): ";
    std::cin >> input_string;
    reading_string += input_string + "\n";
    std::cout << "Gender (M or F): ";
    std::cin >> input_string;
    reading_string += input_string + "\n";
    std::cout << "Age: ";
    std::cin >> input_string;
    reading_string += input_string + "\n";
    std::cout << reading_string;
    patient_stream = std::stringstream(reading_string);

    // all of that just for this moment:
    patient_stream >> patient;
    patients.push_back(patient); // save in memory
    patient.write_patient();     // write to file
    write_file();
  }
  void menu_add_vist() {
    std::string reading_string;
    std::string input_string;
    int patient_id;

    std::cout << "Patient file number: ";
    std::cin >> patient_id;
    std::cout << "Date:";
    std::cin >> input_string;
    reading_string += input_string + " ";
    std::cout << "Doctor's First Name: ";
    std::cin >> input_string;
    reading_string += input_string + " ";
    std::cout << "Doctors's Last Name: ";
    std::cin >> input_string;
    reading_string += input_string + " ";

    std::stringstream visit_stream = std::stringstream(reading_string);
    Visit visit;
    visit_stream >> visit;
    auto patient = find_patient(patient_id);
    if (patient.has_value())
      patient.value().get().add_visit(visit);
    else
      std::cout << "No Patient exists with id= " << patient_id << "\n";
  }
};

#endif