<?php
// models/User.php
require_once dirname(__DIR__) . '/config/database.php';

class User {
    private $conn;
    private $table_name = "users";

    public $id;
    public $username;
    public $password;
    public $full_name;
    public $role;
    public $department_id;
    public $status;

    public function __construct() {
        $this->conn = Database::getInstance();
    }

    public function login($username, $password) {
        $query = "SELECT id, username, password, full_name, role, department_id 
                  FROM " . $this->table_name . " 
                  WHERE username = :username LIMIT 0,1";
        
        $stmt = $this->conn->prepare($query);
        $stmt->bindParam(':username', $username);
        $stmt->execute();

        if ($stmt->rowCount() > 0) {
            $row = $stmt->fetch();
            if (password_verify($password, $row['password'])) {
                // Set object properties
                $this->id = $row['id'];
                $this->username = $row['username'];
                $this->full_name = $row['full_name'];
                $this->role = $row['role'];
                $this->department_id = $row['department_id'];
                
                // Update status to online
                $this->updateStatus($this->id, 'online');
                
                return true;
            }
        }
        return false;
    }

    public function updateStatus($user_id, $status) {
        $query = "UPDATE " . $this->table_name . " SET status = :status WHERE id = :id";
        $stmt = $this->conn->prepare($query);
        $stmt->bindParam(':status', $status);
        $stmt->bindParam(':id', $user_id);
        $stmt->execute();
    }

    public function getById($id) {
        $query = "SELECT * FROM " . $this->table_name . " WHERE id = :id LIMIT 1";
        $stmt = $this->conn->prepare($query);
        $stmt->bindParam(':id', $id);
        $stmt->execute();
        
        if ($stmt->rowCount() > 0) {
            return $stmt->fetch();
        }
        return false;
    }

    public function getAll() {
        $query = "SELECT u.*, d.name as department_name 
                  FROM " . $this->table_name . " u
                  LEFT JOIN departments d ON u.department_id = d.id 
                  ORDER BY u.created_at DESC";
        $stmt = $this->conn->prepare($query);
        $stmt->execute();
        return $stmt->fetchAll();
    }

    public function add($username, $password, $full_name, $role, $department_id = null) {
        $query = "INSERT INTO " . $this->table_name . " (username, password, full_name, role, department_id, status) 
                  VALUES (:username, :password, :full_name, :role, :department_id, 'offline')";
        
        $hashed_password = password_hash($password, PASSWORD_DEFAULT);
        
        $stmt = $this->conn->prepare($query);
        $stmt->bindParam(':username', $username);
        $stmt->bindParam(':password', $hashed_password);
        $stmt->bindParam(':full_name', $full_name);
        $stmt->bindParam(':role', $role);
        
        if ($department_id) {
            $stmt->bindParam(':department_id', $department_id);
        } else {
            $stmt->bindValue(':department_id', null, PDO::PARAM_NULL);
        }
        
        return $stmt->execute();
    }

    public function update($id, $full_name, $role, $department_id = null) {
        $query = "UPDATE " . $this->table_name . " 
                  SET full_name = :full_name, role = :role, department_id = :department_id 
                  WHERE id = :id";
        
        $stmt = $this->conn->prepare($query);
        $stmt->bindParam(':full_name', $full_name);
        $stmt->bindParam(':role', $role);
        $stmt->bindParam(':id', $id);
        
        if ($department_id) {
            $stmt->bindParam(':department_id', $department_id);
        } else {
            $stmt->bindValue(':department_id', null, PDO::PARAM_NULL);
        }
        
        return $stmt->execute();
    }

    public function updatePassword($id, $password) {
        $query = "UPDATE " . $this->table_name . " SET password = :password WHERE id = :id";
        $hashed_password = password_hash($password, PASSWORD_DEFAULT);
        
        $stmt = $this->conn->prepare($query);
        $stmt->bindParam(':password', $hashed_password);
        $stmt->bindParam(':id', $id);
        return $stmt->execute();
    }

    public function delete($id) {
        // Since we have foreign keys, we might want to just set status or delete.
        // Assuming delete for now based on schema constraints (SET NULL or CASCADE might be needed)
        // Schema has jobs.requester_id and jobs.assigned_to referencing users(id). 
        // Deleting a user with jobs will fail unless we handle it, or we can soft delete.
        // For simplicity, let's hard delete, but if it fails it throws PDOException.
        $query = "DELETE FROM " . $this->table_name . " WHERE id = :id";
        $stmt = $this->conn->prepare($query);
        $stmt->bindParam(':id', $id);
        return $stmt->execute();
    }

    public function getAvailableStaff() {
        // Find staff who are online and NOT currently handling an active job
        // Order by who has been idle the longest today
        $query = "
            SELECT u.id, u.full_name, MAX(j.completed_at) as last_job
            FROM " . $this->table_name . " u
            LEFT JOIN jobs j ON u.id = j.assigned_to 
                AND j.status = 'completed' 
                AND DATE(j.created_at) = CURDATE()
            WHERE u.role = 'staff' 
            AND u.status = 'online'
            AND u.id NOT IN (
                SELECT assigned_to 
                FROM jobs 
                WHERE status IN ('assigned', 'accepted', 'in_progress')
                AND assigned_to IS NOT NULL
            )
            GROUP BY u.id
            ORDER BY last_job ASC
            LIMIT 1
        ";
        
        $stmt = $this->conn->query($query);
        if ($stmt->rowCount() > 0) {
            return $stmt->fetch(PDO::FETCH_ASSOC);
        }
        return false;
    }
}