From 081854c35267d9d0ee51ba5858f32e26236077cf Mon Sep 17 00:00:00 2001
From: Mo Farouk <122031508+fmido88@users.noreply.github.com>
Date: Sat, 10 Feb 2024 03:24:22 +0200
Subject: [PATCH] Fix discount calculation logic

---
 classes/util/instance.php | 21 +++++++++----
 classes/util/offers.php   | 63 +++++++++++++++++++++++++++++++++++++--
 2 files changed, 75 insertions(+), 9 deletions(-)

diff --git a/classes/util/instance.php b/classes/util/instance.php
index 1f9d164a..26c1d2f7 100644
--- a/classes/util/instance.php
+++ b/classes/util/instance.php
@@ -252,7 +252,7 @@ private function get_offers_discount() {
                 break;
             case self::B_SEQ;
             default:
-                $discount = $this->calculate_sequential_discount($offers->get_available_discounts());
+                $discount = $this->calculate_sequential_discount($offers->get_available_discounts(), true);
         }
         return min(1, $discount / 100);
     }
@@ -326,7 +326,9 @@ private function calculate_cost_after_discount() {
         $discount = 0;
 
         if ($this->behavior === self::B_SUM) {
-            $discount = array_sum($discounts);
+            foreach ($discounts as $d) {
+                $discount += $d;
+            }
         } else if ($this->behavior === self::B_MAX) {
             $discount = max($discounts);
         } else {
@@ -339,16 +341,23 @@ private function calculate_cost_after_discount() {
     /**
      * sequentially calculate discount
      * @param array $discounts
+     * @param bool $percentage
      * @return float
      */
-    private function calculate_sequential_discount($discounts) {
-        $discount = 0;
+    private function calculate_sequential_discount($discounts, $percentage = false) {
         \core_collator::asort($discounts, \core_collator::SORT_NUMERIC);
         $discounts = array_reverse($discounts);
+
+        $discount = 0;
         foreach ($discounts as $d) {
-            $discount = $discount + $d * (1 - $discount);
+            $d = $percentage ? $d / 100 : $d;
+            $discount = 1 - (1 - $discount) * (1 - $d);
         }
-        return min(1, $discount);
+        $discount = min(1, $discount);
+        if ($percentage) {
+            return $discount * 100;
+        }
+        return $discount;
     }
     /**
      * Get the cost of the enrol instance after discount.
diff --git a/classes/util/offers.php b/classes/util/offers.php
index d98bc90a..27e0cd44 100644
--- a/classes/util/offers.php
+++ b/classes/util/offers.php
@@ -25,6 +25,7 @@
  */
 
 namespace enrol_wallet\util;
+use stdClass;
 
 defined('MOODLE_INTERNAL') || die();
 global $CFG;
@@ -143,7 +144,7 @@ public function __construct($instance, $userid = 0) {
             $this->userid = $USER->id;
         }
         if (!empty($instance->customtext3)) {
-            $this->offers = json_decode($instance->customtext3);
+            $this->offers = (array)json_decode($instance->customtext3);
         } else {
             $this->offers = [];
         }
@@ -227,7 +228,7 @@ public function get_detailed_offers() {
                         'op' => get_string('offers_pfop_'.$offer->op, 'enrol_wallet'),
                         'discount' => $offer->discount,
                         'field' => $fieldname,
-                        'value' => $offer->v,
+                        'value' => $offer->value,
                     ];
                     $descriptions[$key] = get_string('offers_pf_desc', 'enrol_wallet', $a);
                     break;
@@ -301,7 +302,11 @@ public function get_sum_discounts() {
                 return 0;
             }
         }
-        return min(array_sum($this->discounts), 1);
+        $sum = 0;
+        foreach ($this->discounts as $d) {
+            $sum += $d;
+        }
+        return min($sum, 100);
     }
     /**
      * Return array with available valid discounts for the passed user.
@@ -964,6 +969,58 @@ private function get_stored_offers() {
 
         return $return;
     }
+
+    /**
+     * Get all courses with offers and add it to course object $course->offers as array keyed with
+     * instance id and each contain array with offers details.
+     * @param int $categoryid
+     * @return array
+     */
+    public static function get_courses_with_offers($categoryid = 0) {
+        global $DB;
+        $sql = "SELECT e.id as instanceid, c.*, e.customtext3
+        From {course} c
+        JOIN {enrol} e ON  e.courseid = c.id
+            WHERE e.status = :stat
+              AND (e.enrolstartdate < :time1 OR e.enrolstartdate = 0)
+              AND (e.enrolenddate > :time2 OR e.enrolenddate = 0)
+              AND e.enrol = :wallet";
+        $params = [
+            'stat' => ENROL_INSTANCE_ENABLED,
+            'time1' => time(),
+            'time2' => time(),
+            'wallet' => 'wallet',
+        ];
+        if (!empty($categoryid)) {
+            $category = core_course_category::get($categoryid);
+            $catids = $category->get_all_children_ids();
+            $catids[] = $categoryid;
+            list($in, $inparams) = $DB->get_in_or_equal($catids, SQL_PARAMS_NAMED);
+            $sql .= " AND c.category $in";
+            $params = $params + $inparams;
+        }
+        $courses = $DB->get_records_sql($sql, $params);
+        $final = [];
+        foreach ($courses as $instanceid => $course) {
+            $instance = new stdClass;
+            $instance->id = $instanceid;
+            $instance->courseid = $course->id;
+            $instance->customtext3 = $course->customtext3;
+
+            $class = new self($instance);
+            if (empty($class->get_raw_offers())) {
+                continue;
+            }
+            if (!isset($final[$course->id])) {
+                $final[$course->id] = $course;
+                $final[$course->id]->offers = [];
+                unset($final[$course->id]->instanceid);
+                unset($final[$course->id]->customtext3);
+            }
+            $final[$course->id]->offers[$instanceid] = $class;
+        }
+        return $final;
+    }
 }
 
 /**