From cf3c3a0f9e3beb73b3d7a8f1f49dfe76b458a60b Mon Sep 17 00:00:00 2001
From: "branislav.radivojevic" <wafflemynxyt@gmail.com>
Date: Mon, 28 Nov 2022 23:35:55 +0100
Subject: Prva iteracije recommended algoritma

---
 Backend/Api/Api/Controllers/PostController.cs |  7 +++
 Backend/Api/Api/Interfaces/IPostService.cs    |  1 +
 Backend/Api/Api/Models/Post.cs                |  6 +++
 Backend/Api/Api/Services/PostService.cs       | 63 +++++++++++++++++++++++++++
 4 files changed, 77 insertions(+)

(limited to 'Backend/Api')

diff --git a/Backend/Api/Api/Controllers/PostController.cs b/Backend/Api/Api/Controllers/PostController.cs
index 88c1c99..6970d28 100644
--- a/Backend/Api/Api/Controllers/PostController.cs
+++ b/Backend/Api/Api/Controllers/PostController.cs
@@ -171,5 +171,12 @@ namespace Api.Controllers
             return Ok(await _postService.Get10Best());
         }
 
+        [HttpGet("posts/recommended")]
+        [Authorize(Roles = "User")]
+        public async Task<ActionResult<List<PostSend>>> Recommended()
+        {
+            var userid = await _userService.UserIdFromJwt();
+            return Ok(await _postService.Recommended(userid));
+        }
     }
 }
diff --git a/Backend/Api/Api/Interfaces/IPostService.cs b/Backend/Api/Api/Interfaces/IPostService.cs
index a9adb05..96786bd 100644
--- a/Backend/Api/Api/Interfaces/IPostService.cs
+++ b/Backend/Api/Api/Interfaces/IPostService.cs
@@ -26,5 +26,6 @@ namespace Api.Interfaces
         Task<List<PostSend>> Get10MostViewed();
 
         Task<List<PostSend>> Get10Newest();
+        Task<List<PostSend>> Recommended(string userid);
     }
 }
\ No newline at end of file
diff --git a/Backend/Api/Api/Models/Post.cs b/Backend/Api/Api/Models/Post.cs
index 78b4705..dd007ec 100644
--- a/Backend/Api/Api/Models/Post.cs
+++ b/Backend/Api/Api/Models/Post.cs
@@ -108,4 +108,10 @@ namespace Api.Models
         public int totalposts { get; set; }
         public List<PostSend> posts { get; set; }
     }
+
+    public class TagR
+    {
+        public int counter { get; set; }
+        public string tag { get; set; } 
+    }
 }
diff --git a/Backend/Api/Api/Services/PostService.cs b/Backend/Api/Api/Services/PostService.cs
index c57cfec..855b231 100644
--- a/Backend/Api/Api/Services/PostService.cs
+++ b/Backend/Api/Api/Services/PostService.cs
@@ -467,5 +467,68 @@ namespace Api.Services
             List<PostSend> newest = temp.OrderByDescending(o => o.createdAt).Take(10).ToList();
             return newest;
         }
+
+        public async Task<List<PostSend>> Recommended(string userid) // momgodb bloat bleh
+        {
+            List<PostSend> posts = await UserHistory(userid);
+            //TODO-LIMIT RECOMMENDED FOR POSTS FROM THIS MONTH ONLY
+            List<TagR> tags = new List<TagR>();
+            foreach (var post in posts)
+            {
+                if (post.tags != null)
+                {
+
+                    foreach (var tagitem in post.tags)
+                    {
+                        if (!tags.Any(x => x.tag == tagitem))
+                        {
+                            var newtag = new TagR();
+                            newtag.tag = tagitem;
+                            newtag.counter = 1;
+                            tags.Add(newtag);
+                        }
+                        else
+                        {
+                            var replace = tags.Find(x => x.tag == tagitem);
+                            tags.Remove(replace);
+                            replace.counter += 1;
+                            tags.Add(replace);
+                        }
+                    }
+                }
+            }
+            var top5tags = tags.OrderByDescending(x => x.counter).Take(5).ToList();
+            
+            var all = await _posts.Find(_ => true).ToListAsync();
+            var recent30 = new List<PostSend>();
+            var fiveoftop5tags = new List<PostSend>();
+            foreach (var elem in all)
+            {
+                if ((DateTime.Now - elem.createdAt).TotalDays < 30)
+                    recent30.Add(await postToPostSend(elem));
+            }
+            recent30 = recent30.OrderByDescending(x => x.createdAt).ToList();
+            foreach (var tag in top5tags) 
+            {
+                var five = new List<PostSend>();
+                foreach (var elem in recent30)
+                {
+                    if (elem.tags != null)
+                    {
+                        if (elem.tags.Any(x => x == tag.tag))
+                            five.Add(elem);
+                    }
+                }
+                five = five.Take(5).ToList();
+                foreach(var elem in five)
+                {
+                    fiveoftop5tags.Add(elem);
+                }
+            }
+
+            var taggedposts = new List<PostSend>();
+            taggedposts = fiveoftop5tags.Distinct().OrderByDescending(x => x.createdAt).ToList();
+            return taggedposts;
+        }
     }
 }
-- 
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