<?php
defined('BASEPATH') or exit('No direct script access allowed');

/**
 * Campaign Manager Library
 * Business logic untuk handle promotional campaigns
 * 
 */
class CampaignManager
{
    private $CI;
    private $session_key = 'promotional_campaign';
    private $cookie_name = 'promo_campaign';
    private $cookie_expiry = 86400; // 24 hours

    public function __construct()
    {
        $this->CI = &get_instance();
        $this->CI->load->model('Promotional_campaign_m');
        $this->CI->load->model('Promotional_campaign_log_m');
        $this->CI->load->model('Promotional_campaign_usage_m');
    }

    /**
     * Get active campaign by code
     * 
     * @param string $code
     * @return object|null
     */
    public function get_active_campaign($code)
    {
        $campaign = $this->CI->Promotional_campaign_m->get_by_code($code);

        // Check if campaign exists and active
        if (!$campaign || $campaign->is_active != 1 || $campaign->deleted_at !== null) {
            return null;
        }

        return $campaign;
    }

    /**
     * Check if campaign is within valid date range
     * 
     * @param object $campaign
     * @return bool
     */
    public function is_campaign_valid($campaign)
    {
        $now = new DateTime();
        $start = new DateTime($campaign->start_date);
        $end = new DateTime($campaign->end_date);

        return ($now >= $start && $now <= $end);
    }

    /**
     * Check if usage limit reached (global)
     * 
     * @param object $campaign
     * @return bool
     */
    public function is_usage_limit_reached($campaign)
    {
        // No limit set
        if ($campaign->max_usage === null) {
            return false;
        }

        // Check current usage
        return $campaign->current_usage >= $campaign->max_usage;
    }

    /**
     * Check if user has reached personal usage limit
     * 
     * @param int $campaign_id
     * @param int $user_id (null for guest)
     * @param string $session_id
     * @return bool
     */
    public function is_user_limit_reached($campaign_id, $user_id = null, $session_id = null)
    {
        $campaign = $this->CI->Promotional_campaign_m->get_by_id($campaign_id);

        // No per-user limit
        if ($campaign->max_usage_per_user === null) {
            return false;
        }

        $usage_count = $this->CI->Promotional_campaign_usage_m->get_user_usage_count(
            $campaign_id,
            $user_id,
            $session_id
        );

        return $usage_count >= $campaign->max_usage_per_user;
    }

    /**
     * Set campaign data to session
     * 
     * @param object $campaign
     * @return void
     */
    public function set_campaign_session($campaign)
    {
        $campaign_data = [
            'id' => $campaign->id,
            'code' => $campaign->code,
            'name' => $campaign->name,
            'discount_type' => $campaign->discount_type,
            'discount_value' => $campaign->discount_value,
            'min_purchase' => $campaign->min_purchase,
            'max_discount' => $campaign->max_discount,
            'started_at' => time(),
            'expires_at' => strtotime($campaign->end_date),
        ];

        // Set session
        $this->CI->session->set_userdata($this->session_key, $campaign_data);

        // Set cookie as backup (untuk persistent jika session expired)
        $cookie_value = $this->_encrypt_campaign_data($campaign_data);
        $this->CI->input->set_cookie([
            'name' => $this->cookie_name,
            'value' => $cookie_value,
            'expire' => $this->cookie_expiry,
            'path' => '/',
            'secure' => is_https(),
            'httponly' => true
        ]);
    }

    /**
     * Get campaign from session
     * 
     * @return object|null
     */
    public function get_campaign_from_session()
    {
        // Try to get from session first
        $campaign_data = $this->CI->session->userdata($this->session_key);

        // If not in session, try cookie
        if (!$campaign_data) {
            $campaign_data = $this->_restore_from_cookie();
        }

        if (!$campaign_data) {
            return null;
        }

        // Check if expired
        if (time() > $campaign_data['expires_at']) {
            $this->clear_campaign_session();
            return null;
        }

        return (object) $campaign_data;
    }

    /**
     * Clear campaign from session and cookie
     * 
     * @return void
     */
    public function clear_campaign_session()
    {
        $this->CI->session->unset_userdata($this->session_key);
        delete_cookie($this->cookie_name);
    }

    /**
     * Calculate discount for a product based on campaign
     * 
     * @param object $product
     * @param object $campaign
     * @return array [original_price, discount_amount, final_price]
     */
    public function calculate_discount($product, $campaign)
    {
        // Selalu gunakan harga asli (price) dari product_details
        $original_price = (float) $product->price;
        $discount_amount = 0;
        $final_price = $original_price;

        switch ($campaign->discount_type) {
            case 'percentage':
                $discount_amount = $original_price * ($campaign->discount_value / 100);

                // Apply max discount jika ada
                if (!empty($campaign->max_discount) && $discount_amount > $campaign->max_discount) {
                    $discount_amount = (float) $campaign->max_discount;
                }
                break;

            case 'fixed_amount':
                $discount_amount = (float) $campaign->discount_value;

                // Jangan biarkan diskon lebih besar dari harga
                if ($discount_amount > $original_price) {
                    $discount_amount = $original_price;
                }
                break;

            case 'free_shipping':
                // Ditangani di checkout
                $discount_amount = 0;
                break;
        }

        $final_price = $original_price - $discount_amount;

        return [
            'original_price'       => $original_price,
            'discount_amount'      => $discount_amount,
            'final_price'          => max(0, $final_price), // Tidak boleh negatif
            'discount_percentage'  => $original_price > 0 ? round(($discount_amount / $original_price) * 100) : 0
        ];
    }

    /**
     * Apply discount to array of products
     * 
     * @param array $products
     * @param object $campaign
     * @return array
     */
    public function apply_discount_to_products($products, $campaign)
    {
        foreach ($products as &$product) {
            $discount_data = $this->calculate_discount($product, $campaign);

            $product->original_price      = $discount_data['original_price'];
            $product->discount_amount     = $discount_data['discount_amount'];
            $product->discounted_price    = $discount_data['final_price'];
            $product->discount_percentage = $discount_data['discount_percentage'];
            $product->has_campaign        = true;
        }

        return $products;
    }

    /**
     * Apply discount to array of products (associative array format)
     * 
     * @param array $products (result_array format)
     * @param object $campaign
     * @return array
     */
    public function apply_discount_to_products_array($products, $campaign)
    {
        foreach ($products as &$product) {
            // Convert to object temporarily untuk calculate_discount
            $product_obj = (object) $product;

            $discount_data = $this->calculate_discount($product_obj, $campaign);

            // Update array
            $product['original_price'] = $discount_data['original_price'];
            $product['discount_amount'] = $discount_data['discount_amount'];
            $product['discounted_price'] = $discount_data['final_price'];
            $product['discount_percentage'] = $discount_data['discount_percentage'];
            $product['has_campaign'] = true;
        }

        return $products;
    }

    /**
     * Log campaign access for analytics
     * 
     * @param int $campaign_id
     * @param string $action_type (view, click_product, add_to_cart, checkout)
     * @param int $product_id (optional)
     * @return void
     */
    public function log_campaign_access($campaign_id, $action_type = 'view', $product_id = null)
    {
        $log_data = [
            'campaign_id' => $campaign_id,
            'user_id' => $this->CI->session->userdata('user_id'), // null if guest
            'session_id' => session_id(),
            'ip_address' => $this->CI->input->ip_address(),
            'user_agent' => $this->CI->input->user_agent(),
            'referrer' => $this->CI->input->server('HTTP_REFERER'),
            'action_type' => $action_type,
            'product_id' => $product_id,
        ];

        $this->CI->Promotional_campaign_log_m->insert($log_data);
    }

    /**
     * Record campaign usage (when order completed)
     * 
     * @param int $campaign_id
     * @param int $order_id
     * @param float $discount_amount
     * @return bool
     */
    public function record_usage($campaign_id, $order_id, $discount_amount)
    {
        $usage_data = [
            'campaign_id' => $campaign_id,
            'user_id' => $this->CI->session->userdata('user_id'),
            'session_id' => session_id(),
            'ip_address' => $this->CI->input->ip_address(),
            'order_id' => $order_id,
            'discount_amount' => $discount_amount,
        ];

        // Insert usage record
        $this->CI->Promotional_campaign_usage_m->insert($usage_data);

        // Increment campaign usage counter
        $this->CI->Promotional_campaign_m->increment_usage($campaign_id);

        return true;
    }

    /**
     * Encrypt campaign data for cookie
     * 
     * @param array $data
     * @return string
     */
    private function _encrypt_campaign_data($data)
    {
        $this->CI->load->library('encryption');
        return base64_encode($this->CI->encryption->encrypt(json_encode($data)));
    }

    /**
     * Decrypt campaign data from cookie
     * 
     * @return array|null
     */
    private function _restore_from_cookie()
    {
        $cookie_value = $this->CI->input->cookie($this->cookie_name);

        if (!$cookie_value) {
            return null;
        }

        try {
            $this->CI->load->library('encryption');
            $decrypted = $this->CI->encryption->decrypt(base64_decode($cookie_value));
            $campaign_data = json_decode($decrypted, true);

            // Restore to session
            if ($campaign_data) {
                $this->CI->session->set_userdata($this->session_key, $campaign_data);
            }

            return $campaign_data;
        } catch (Exception $e) {
            // Invalid cookie, delete it
            delete_cookie($this->cookie_name);
            return null;
        }
    }
}