From 60cf54d80e62ea9180660e5a951c569f90bc4636 Mon Sep 17 00:00:00 2001
From: crupest <crupest@outlook.com>
Date: Thu, 26 Nov 2020 20:02:03 +0800
Subject: feat: Add highlight timeline entity and service.

---
 .../Timeline/Services/HighlightTimelineService.cs  | 112 +++++++++++++++++++++
 1 file changed, 112 insertions(+)
 create mode 100644 BackEnd/Timeline/Services/HighlightTimelineService.cs

(limited to 'BackEnd/Timeline/Services/HighlightTimelineService.cs')

diff --git a/BackEnd/Timeline/Services/HighlightTimelineService.cs b/BackEnd/Timeline/Services/HighlightTimelineService.cs
new file mode 100644
index 00000000..7528d9b0
--- /dev/null
+++ b/BackEnd/Timeline/Services/HighlightTimelineService.cs
@@ -0,0 +1,112 @@
+using Microsoft.EntityFrameworkCore;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading.Tasks;
+using Timeline.Entities;
+using Timeline.Services.Exceptions;
+
+namespace Timeline.Services
+{
+    public interface IHighlightTimelineService
+    {
+        /// <summary>
+        /// Get all highlight timelines.
+        /// </summary>
+        /// <returns>A list of all highlight timelines.</returns>
+        Task<List<Models.Timeline>> GetHighlightTimelines();
+
+        /// <summary>
+        /// Add a timeline to highlight list.
+        /// </summary>
+        /// <param name="timelineName">The timeline name.</param>
+        /// <param name="operatorId">The user id of operator.</param>
+        /// <exception cref="ArgumentNullException">Thrown when <paramref name="timelineName"/> is null.</exception>
+        /// <exception cref="ArgumentException">Thrown when <paramref name="timelineName"/> is not a valid timeline name.</exception>
+        /// <exception cref="TimelineNotExistException">Thrown when timeline with given name does not exist.</exception>
+        /// <exception cref="UserNotExistException">Thrown when user with given operator id does not exist.</exception>
+        Task AddHighlightTimeline(string timelineName, long? operatorId);
+
+        /// <summary>
+        /// Remove a timeline from highlight list.
+        /// </summary>
+        /// <param name="timelineName">The timeline name.</param>
+        /// <param name="operatorId">The user id of operator.</param>
+        /// <returns>True if deletion is actually performed. Otherwise false (timeline was not in the list).</returns>
+        /// <exception cref="ArgumentNullException">Thrown when <paramref name="timelineName"/> is null.</exception>
+        /// <exception cref="ArgumentException">Thrown when <paramref name="timelineName"/> is not a valid timeline name.</exception>
+        /// <exception cref="TimelineNotExistException">Thrown when timeline with given name does not exist.</exception>
+        /// <exception cref="UserNotExistException">Thrown when user with given operator id does not exist.</exception>
+        Task<bool> RemoveHighlightTimeline(string timelineName, long? operatorId);
+    }
+
+    public class HighlightTimelineService : IHighlightTimelineService
+    {
+        private readonly DatabaseContext _database;
+        private readonly IUserService _userService;
+        private readonly ITimelineService _timelineService;
+
+        public HighlightTimelineService(DatabaseContext database, IUserService userService, ITimelineService timelineService)
+        {
+            _database = database;
+            _userService = userService;
+            _timelineService = timelineService;
+        }
+
+        public async Task AddHighlightTimeline(string timelineName, long? operatorId)
+        {
+            if (timelineName == null)
+                throw new ArgumentNullException(nameof(timelineName));
+
+            var timelineId = await _timelineService.GetTimelineIdByName(timelineName);
+
+            if (operatorId.HasValue && !await _userService.CheckUserExistence(operatorId.Value))
+            {
+                throw new UserNotExistException(null, operatorId.Value, "User with given operator id does not exist.", null);
+            }
+
+            var alreadyIs = await _database.HighlightTimelines.AnyAsync(t => t.TimelineId == timelineId);
+
+            if (alreadyIs) return;
+
+            _database.HighlightTimelines.Add(new HighlightTimelineEntity { TimelineId = timelineId, OperatorId = operatorId });
+            await _database.SaveChangesAsync();
+        }
+
+        public async Task<List<Models.Timeline>> GetHighlightTimelines()
+        {
+            var entities = await _database.HighlightTimelines.Select(t => new { t.Id }).ToListAsync();
+
+            var result = new List<Models.Timeline>();
+
+            foreach (var entity in entities)
+            {
+                result.Add(await _timelineService.GetTimelineById(entity.Id));
+            }
+
+            return result;
+        }
+
+        public async Task<bool> RemoveHighlightTimeline(string timelineName, long? operatorId)
+        {
+            if (timelineName == null)
+                throw new ArgumentNullException(nameof(timelineName));
+
+            var timelineId = await _timelineService.GetTimelineIdByName(timelineName);
+
+            if (operatorId.HasValue && !await _userService.CheckUserExistence(operatorId.Value))
+            {
+                throw new UserNotExistException(null, operatorId.Value, "User with given operator id does not exist.", null);
+            }
+
+            var entity = await _database.HighlightTimelines.SingleOrDefaultAsync(t => t.TimelineId == timelineId);
+
+            if (entity == null) return false;
+
+            _database.HighlightTimelines.Remove(entity);
+            await _database.SaveChangesAsync();
+
+            return true;
+        }
+    }
+}
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