feat(backend): global notices

Foxnouns.Backend/Controllers/Moderation/NoticesController.cs

@@ -0,0 +1,77 @@
+using Foxnouns.Backend.Database;
+using Foxnouns.Backend.Database.Models;
+using Foxnouns.Backend.Dto;
+using Foxnouns.Backend.Middleware;
+using Foxnouns.Backend.Services;
+using Microsoft.AspNetCore.Mvc;
+using Microsoft.EntityFrameworkCore;
+using NodaTime;
+
+namespace Foxnouns.Backend.Controllers.Moderation;
+
+[Route("/api/v2/notices")]
+[Authorize("user.moderation")]
+[Limit(RequireModerator = true)]
+public class NoticesController(
+    DatabaseContext db,
+    UserRendererService userRenderer,
+    ISnowflakeGenerator snowflakeGenerator,
+    IClock clock
+) : ApiControllerBase
+{
+    [HttpGet]
+    public async Task<IActionResult> GetNoticesAsync(CancellationToken ct = default)
+    {
+        List<Notice> notices = await db
+            .Notices.Include(n => n.Author)
+            .OrderByDescending(n => n.Id)
+            .ToListAsync(ct);
+        return Ok(notices.Select(RenderNotice));
+    }
+
+    [HttpPost]
+    public async Task<IActionResult> CreateNoticeAsync(CreateNoticeRequest req)
+    {
+        Instant now = clock.GetCurrentInstant();
+        if (req.StartTime < now)
+        {
+            throw new ApiError.BadRequest(
+                "Start time cannot be in the past",
+                "start_time",
+                req.StartTime
+            );
+        }
+
+        if (req.EndTime < now)
+        {
+            throw new ApiError.BadRequest(
+                "End time cannot be in the past",
+                "end_time",
+                req.EndTime
+            );
+        }
+
+        var notice = new Notice
+        {
+            Id = snowflakeGenerator.GenerateSnowflake(),
+            Message = req.Message,
+            StartTime = req.StartTime ?? clock.GetCurrentInstant(),
+            EndTime = req.EndTime,
+            Author = CurrentUser!,
+        };
+
+        db.Add(notice);
+        await db.SaveChangesAsync();
+
+        return Ok(RenderNotice(notice));
+    }
+
+    private NoticeResponse RenderNotice(Notice notice) =>
+        new(
+            notice.Id,
+            notice.Message,
+            notice.StartTime,
+            notice.EndTime,
+            userRenderer.RenderPartialUser(notice.Author)
+        );
+}