using CampusErrand.Data;
using CampusErrand.Models;
using CampusErrand.Models.Dtos;
using CampusErrand.Helpers;
using Microsoft.EntityFrameworkCore;

namespace CampusErrand.Endpoints;

public static class MessageEndpoints
{
    public static void MapMessageEndpoints(this WebApplication app)
    {
        // 获取未读消息数
        app.MapGet("/api/messages/unread-count", async (HttpContext httpContext, AppDbContext db) =>
        {
            var userIdClaim = httpContext.User.FindFirst(System.Security.Claims.ClaimTypes.NameIdentifier);
            if (userIdClaim == null) return Results.Unauthorized();
            var userId = int.Parse(userIdClaim.Value);

            // 获取该用户可见的系统消息（按目标类型过滤）
            var user = await db.Users.FindAsync(userId);
            var visibleSystemMessages = await BusinessHelpers.GetVisibleSystemMessages(db, userId, user);
            var visibleSystemMessageIds = visibleSystemMessages.Select(m => m.Id).ToHashSet();

            // 已读的系统消息 ID
            var readSystemIds = await db.MessageReads
                .Where(r => r.UserId == userId && r.MessageType == MessageType.System)
                .Select(r => r.MessageId)
                .ToListAsync();

            var systemUnread = visibleSystemMessageIds.Count(id => !readSystemIds.Contains(id));

            // 订单通知：用户相关的订单中状态变更过的订单数
            var orderNotifications = await db.Orders
                .Where(o => (o.OwnerId == userId || o.RunnerId == userId) && o.Status != OrderStatus.Pending)
                .Select(o => o.Id)
                .ToListAsync();

            var readOrderNotificationIds = await db.MessageReads
                .Where(r => r.UserId == userId && r.MessageType == MessageType.OrderNotification)
                .Select(r => r.MessageId)
                .ToListAsync();

            var orderNotificationUnread = orderNotifications.Count(id => !readOrderNotificationIds.Contains(id));

            return Results.Ok(new UnreadCountResponse
            {
                SystemUnread = systemUnread,
                OrderNotificationUnread = orderNotificationUnread,
                TotalUnread = systemUnread + orderNotificationUnread
            });
        }).RequireAuthorization();

        // 获取系统消息列表
        app.MapGet("/api/messages/system", async (HttpContext httpContext, AppDbContext db) =>
        {
            var userIdClaim = httpContext.User.FindFirst(System.Security.Claims.ClaimTypes.NameIdentifier);
            if (userIdClaim == null) return Results.Unauthorized();
            var userId = int.Parse(userIdClaim.Value);

            var user = await db.Users.FindAsync(userId);
            var messages = await BusinessHelpers.GetVisibleSystemMessages(db, userId, user);

            // 获取已读记录
            var readIds = await db.MessageReads
                .Where(r => r.UserId == userId && r.MessageType == MessageType.System)
                .Select(r => r.MessageId)
                .ToListAsync();

            var result = messages
                .OrderByDescending(m => m.CreatedAt)
                .Select(m => new SystemMessageResponse
                {
                    Id = m.Id,
                    Title = m.Title,
                    ContentPreview = m.Content.Length > 100 ? m.Content[..100] + "…" : m.Content,
                    ThumbnailUrl = m.ThumbnailUrl,
                    CreatedAt = m.CreatedAt,
                    IsRead = readIds.Contains(m.Id)
                })
                .ToList();

            // 标记所有为已读
            foreach (var msg in messages.Where(m => !readIds.Contains(m.Id)))
            {
                db.MessageReads.Add(new MessageRead
                {
                    UserId = userId,
                    MessageType = MessageType.System,
                    MessageId = msg.Id,
                    ReadAt = DateTime.UtcNow
                });
            }
            await db.SaveChangesAsync();

            return Results.Ok(result);
        }).RequireAuthorization();

        // 获取系统消息详情
        app.MapGet("/api/messages/system/{id}", async (int id, HttpContext httpContext, AppDbContext db) =>
        {
            var userIdClaim = httpContext.User.FindFirst(System.Security.Claims.ClaimTypes.NameIdentifier);
            if (userIdClaim == null) return Results.Unauthorized();

            var message = await db.SystemMessages.FindAsync(id);
            if (message == null) return Results.NotFound(new { code = 404, message = "消息不存在" });

            return Results.Ok(new SystemMessageDetailResponse
            {
                Id = message.Id,
                Title = message.Title,
                Content = message.Content,
                ThumbnailUrl = message.ThumbnailUrl,
                CreatedAt = message.CreatedAt
            });
        }).RequireAuthorization();

        // 获取订单通知列表
        app.MapGet("/api/messages/order-notifications", async (string? category, HttpContext httpContext, AppDbContext db) =>
        {
            var userIdClaim = httpContext.User.FindFirst(System.Security.Claims.ClaimTypes.NameIdentifier);
            if (userIdClaim == null) return Results.Unauthorized();
            var userId = int.Parse(userIdClaim.Value);

            // 查询用户相关的订单（状态已变更的）
            var query = db.Orders
                .Where(o => (o.OwnerId == userId || o.RunnerId == userId) && o.Status != OrderStatus.Pending);

            // 按分类筛选
            if (!string.IsNullOrEmpty(category))
            {
                query = category.ToLower() switch
                {
                    "accepted" => query.Where(o => o.Status == OrderStatus.InProgress),
                    "completed" => query.Where(o => o.Status == OrderStatus.Completed),
                    "cancelled" => query.Where(o => o.Status == OrderStatus.Cancelled),
                    _ => query
                };
            }

            var orders = await query
                .OrderByDescending(o => o.AcceptedAt ?? o.CreatedAt)
                .Select(o => new OrderNotificationResponse
                {
                    Id = o.Id,
                    OrderNo = o.OrderNo,
                    OrderType = o.OrderType.ToString(),
                    Title = o.Status == OrderStatus.InProgress
                          ? (o.OwnerId == userId ? "订单已被接取" : "您已接取订单")
                          : o.Status == OrderStatus.Completed
                          ? (o.RunnerId == userId ? "单主已确认完成" : "订单已完成")
                          : o.Status == OrderStatus.Cancelled ? "订单已取消"
                          : o.Status == OrderStatus.WaitConfirm
                          ? (o.OwnerId == userId ? "跑腿已提交完成，请确认" : "等待单主确认完成")
                          : o.Status == OrderStatus.Appealing ? "订单申诉中"
                          : "订单状态变更",
                    ItemName = o.ItemName,
                    Status = o.Status.ToString(),
                    CreatedAt = o.AcceptedAt ?? o.CreatedAt
                })
                .ToListAsync();

            // 标记订单通知为已读
            var orderIds = orders.Select(o => o.Id).ToList();
            var readIds = await db.MessageReads
                .Where(r => r.UserId == userId && r.MessageType == MessageType.OrderNotification && orderIds.Contains(r.MessageId))
                .Select(r => r.MessageId)
                .ToListAsync();

            foreach (var orderId in orderIds.Where(id => !readIds.Contains(id)))
            {
                db.MessageReads.Add(new MessageRead
                {
                    UserId = userId,
                    MessageType = MessageType.OrderNotification,
                    MessageId = orderId,
                    ReadAt = DateTime.UtcNow
                });
            }
            await db.SaveChangesAsync();

            return Results.Ok(orders);
        }).RequireAuthorization();

        // 管理端获取已发送通知列表
        app.MapGet("/api/admin/notifications", async (AppDbContext db) =>
        {
            var list = await db.SystemMessages
                .OrderByDescending(m => m.CreatedAt)
                .Select(m => new
                {
                    m.Id,
                    m.Title,
                    ContentPreview = m.Content.Length > 80 ? m.Content.Substring(0, 80) + "…" : m.Content,
                    m.ThumbnailUrl,
                    TargetType = m.TargetType.ToString(),
                    m.TargetUserIds,
                    m.CreatedAt
                })
                .ToListAsync();

            return Results.Ok(list);
        }).RequireAuthorization("AdminOnly");

        // 管理端发布系统通知
        app.MapPost("/api/admin/notifications", async (CreateNotificationRequest request, AppDbContext db) =>
        {
            // 校验
            var errors = new List<object>();
            if (string.IsNullOrWhiteSpace(request.Title))
                errors.Add(new { field = "title", message = "标题不能为空" });
            if (string.IsNullOrWhiteSpace(request.Content))
                errors.Add(new { field = "content", message = "正文不能为空" });
            if (errors.Count > 0)
                return Results.BadRequest(new { code = 400, message = "校验失败", errors });

            if (!Enum.TryParse<MessageTargetType>(request.TargetType, true, out var targetType) || !Enum.IsDefined(targetType))
                return Results.BadRequest(new { code = 400, message = "目标类型不合法" });

            var message = new SystemMessage
            {
                Title = request.Title,
                Content = request.Content,
                ThumbnailUrl = request.ThumbnailUrl,
                TargetType = targetType,
                TargetUserIds = request.TargetUserIds != null
                    ? System.Text.Json.JsonSerializer.Serialize(request.TargetUserIds)
                    : null,
                CreatedAt = DateTime.UtcNow
            };

            db.SystemMessages.Add(message);
            await db.SaveChangesAsync();

            return Results.Created($"/api/admin/notifications/{message.Id}", new SystemMessageDetailResponse
            {
                Id = message.Id,
                Title = message.Title,
                Content = message.Content,
                ThumbnailUrl = message.ThumbnailUrl,
                CreatedAt = message.CreatedAt
            });
        }).RequireAuthorization("AdminOnly");

        // 管理端删除通知
        app.MapDelete("/api/admin/notifications/{id}", async (int id, AppDbContext db) =>
        {
            var msg = await db.SystemMessages.FindAsync(id);
            if (msg == null)
                return Results.NotFound(new { code = 404, message = "通知不存在" });

            // 删除关联的已读记录
            db.MessageReads.RemoveRange(
                db.MessageReads.Where(r => r.MessageType == MessageType.System && r.MessageId == id));
            db.SystemMessages.Remove(msg);
            await db.SaveChangesAsync();

            return Results.Ok(new { message = "已删除" });
        }).RequireAuthorization("AdminOnly");
    }
}