using System.Threading.Tasks;
using F9MES.Application.Im;
using F9MES.Common.Auth;
using F9MES.Common.Result;
using Microsoft.AspNetCore.Authorization;
using Microsoft.AspNetCore.Mvc;

namespace F9MES.Api.Controllers;

/// <summary>轻量 IM：单聊 + 系统通知（SSE 长连接实时推送）</summary>
[ApiController]
[Route("api/im")]
[Authorize]
public class ImController : ControllerBase
{
    private readonly ImService _im;
    private readonly ImEventHub _hub;
    private readonly CurrentUserService _currentUser;

    public ImController(ImService im, ImEventHub hub, CurrentUserService currentUser)
    {
        _im = im;
        _hub = hub;
        _currentUser = currentUser;
    }

    /// <summary>
    /// SSE 长连接：订阅新消息/通知的实时推送。
    /// 客户端用 fetch 流式读取（EventSource 无法携带 Authorization header），
    /// 收到 message 事件后刷新会话/消息列表即可，无需再轮询。
    /// </summary>
    [HttpGet("events")]
    public async Task Events(CancellationToken ct)
    {
        var me = _currentUser.UserId;
        if (me <= 0)
        {
            Response.StatusCode = StatusCodes.Status401Unauthorized;
            return;
        }
        _im.TouchActive();
        Response.ContentType = "text/event-stream";
        Response.Headers.CacheControl = "no-cache";
        Response.Headers.Append("Connection", "keep-alive");
        await _hub.SubscribeAsync(me, Response, ct);
    }

    /// <summary>会话列表</summary>
    [HttpGet("sessions")]
    public async Task<ActionResult> Sessions()
    {
        var list = await _im.GetSessionsAsync();
        return Ok(ApiResult.Ok(list));
    }

    /// <summary>与某人的聊天记录</summary>
    [HttpGet("messages")]
    public async Task<ActionResult> Messages([FromQuery] long peerId, [FromQuery] int page = 1, [FromQuery] int size = 20)
    {
        var (items, total) = await _im.GetMessagesAsync(peerId, page, size);
        return Ok(ApiResult.Ok(new { items, total, page, size }));
    }

    /// <summary>发送单聊消息</summary>
    [HttpPost("send")]
    public async Task<ActionResult> Send([FromBody] ImSendInput input)
    {
        await _im.SendAsync(input.PeerId, input.Content);
        return Ok(ApiResult.Ok(true, "发送成功"));
    }

    /// <summary>标记与某人的会话已读</summary>
    [HttpPost("read")]
    public async Task<ActionResult> Read([FromBody] ImReadInput input)
    {
        await _im.ReadAsync(input.PeerId);
        return Ok(ApiResult.Ok(true));
    }

    /// <summary>未读消息总数（顶栏角标）</summary>
    [HttpGet("unread-count")]
    public async Task<ActionResult> UnreadCount()
    {
        var count = await _im.GetUnreadCountAsync();
        return Ok(ApiResult.Ok(count));
    }

    /// <summary>系统/业务通知群发（工单/工艺单变更等）</summary>
    [HttpPost("notify")]
    public async Task<ActionResult> Notify([FromBody] ImNotifyInput input)
    {
        var count = await _im.NotifyAsync(input);
        return Ok(ApiResult.Ok(count, $"已发送 {count} 条通知"));
    }
}