using System.Net.NetworkInformation;
using System.Net.Sockets;
using AgriculturalPlatform.Api.Services;
using Microsoft.AspNetCore.Authorization;
using Microsoft.AspNetCore.Mvc;

namespace AgriculturalPlatform.Api.Controllers;

/// <summary>
/// 附件上传（身份证正反面）：高拍仪/本地拍照直传 + 手机扫码上传。
/// 图片保存为附件（本地存储，OSS 配置后自动切换），并返回 OCR 识别结果。
/// </summary>
[ApiController]
[Route("api/uploads")]
public class UploadsController(
    IFileStorage storage,
    IOcrService ocr,
    MobileUploadSessionStore sessions,
    IConfiguration cfg) : ControllerBase
{
    /// <summary>
    /// 高拍仪/本地拍照：上传身份证单面图片（side = front 正面 | back 反面），
    /// 返回附件地址（url/key）与 OCR 识别结果。
    /// </summary>
    [HttpPost("idcard")]
    [Authorize]
    [RequestSizeLimit(15 * 1024 * 1024)]
    public async Task<ActionResult> UploadIdCard(IFormFile? file, [FromForm] string? side)
    {
        if (file is null || file.Length == 0)
            return BadRequest(new { message = "请先拍摄或选择身份证图片" });

        side = side == "back" ? "back" : "front";
        await using var ms = new MemoryStream();
        await file.CopyToAsync(ms);
        ms.Position = 0;

        StoredFile saved;
        try
        {
            saved = await storage.SaveAsync("idcard", ms, file.FileName, file.ContentType);
        }
        catch (InvalidOperationException ex)
        {
            return BadRequest(new { message = ex.Message });
        }

        // 反面仅存档至 OSS，不调用 OCR（OCR 只识别正面）
        IdCardOcrResult? result = null;
        if (side == "front")
            result = await ocr.RecognizeAsync(ms, side, file.FileName, saved.Key);
        return Ok(new { url = saved.Url, key = saved.Key, side, ocr = result });
    }

    /// <summary>
    /// 手机传图：创建上传会话，返回二维码内容（手机访问的 URL）。
    /// 电脑端展示二维码，手机扫码后访问 /mobile-upload.html?code=xxx 上传身份证正反面。
    /// 注意：端口固定取 Server:LanPort（默认 5246），不依赖请求 Host，
    /// 因为经 Vite 代理（5173）访问时 Host 端口可能是前端端口，手机无法访问该端口。
    /// </summary>
    [HttpGet("qr")]
    [Authorize]
    public ActionResult<object> CreateQr()
    {
        var code = sessions.Create();
        // 优先取 TCP 连接本端地址（后端监听 0.0.0.0 时即手机可直达的局域网 IP），回环则回退枚举网卡
        var localIp = HttpContext.Connection.LocalIpAddress?.ToString() ?? "";
        var lanIp = localIp.StartsWith("127.") || localIp.StartsWith("::1") || localIp.StartsWith("::ffff:127.")
            ? GetLanIp()
            : localIp;
        var port = cfg["Server:LanPort"] ?? "5246";
        var url = $"http://{lanIp}:{port}/mobile-upload.html?code={code}";
        return Ok(new { code, url, expiresAt = DateTime.Now.AddMinutes(10) });
    }

    /// <summary>
    /// 农户头像上传：摄像头/本地图片直传，返回附件地址。
    /// 图片保存于 avatar 目录，未来可用于人脸识别收购（届时在识别服务中引用 AvatarUrl）。
    /// </summary>
    [HttpPost("avatar")]
    [Authorize]
    [RequestSizeLimit(15 * 1024 * 1024)]
    public async Task<ActionResult> UploadAvatar(IFormFile? file)
    {
        if (file is null || file.Length == 0)
            return BadRequest(new { message = "请先拍摄或选择头像图片" });

        await using var ms = new MemoryStream();
        await file.CopyToAsync(ms);
        ms.Position = 0;

        StoredFile saved;
        try
        {
            saved = await storage.SaveAsync("avatar", ms, file.FileName, file.ContentType);
        }
        catch (InvalidOperationException ex)
        {
            return BadRequest(new { message = ex.Message });
        }

        return Ok(new { url = saved.Url, key = saved.Key });
    }

    /// <summary>手机上传身份证正反面（front/back 两张图，允许只传一张）</summary>
    [HttpPost("mobile")]
    [AllowAnonymous]
    [RequestSizeLimit(30 * 1024 * 1024)]
    public async Task<ActionResult> MobileUpload(
        [FromForm] string? code,
        IFormFile? front,
        IFormFile? back)
    {
        var session = sessions.Get(code ?? "");
        if (session is null || session.Done)
            return BadRequest(new { message = "二维码已失效，请回到电脑端重新生成" });

        if (front is not null && front.Length > 0)
        {
            await using var ms = new MemoryStream();
            await front.CopyToAsync(ms);
            ms.Position = 0;
            try
            {
                session.Front = await storage.SaveAsync("idcard", ms, front.FileName, front.ContentType);
                session.FrontOcr = await ocr.RecognizeAsync(ms, "front", front.FileName, session.Front.Key);
            }
            catch (InvalidOperationException ex)
            {
                return BadRequest(new { message = ex.Message });
            }
        }

        if (back is not null && back.Length > 0)
        {
            await using var ms = new MemoryStream();
            await back.CopyToAsync(ms);
            ms.Position = 0;
            try
            {
                // 反面仅存档，不调用 OCR
                session.Back = await storage.SaveAsync("idcard", ms, back.FileName, back.ContentType);
                session.BackOcr = null;
            }
            catch (InvalidOperationException ex)
            {
                return BadRequest(new { message = ex.Message });
            }
        }

        session.Done = true;
        return Ok(new { ok = true, message = "上传成功，请回到电脑端查看" });
    }

    /// <summary>电脑端轮询手机上传结果（done=false 表示手机还未传完）</summary>
    [HttpGet("mobile/{code}/result")]
    [Authorize]
    public ActionResult<object> MobileResult(string code)
    {
        var session = sessions.Get(code);
        if (session is null)
            return NotFound(new { message = "二维码已失效，请重新生成" });
        if (!session.Done)
            return Ok(new { done = false });

        // 反面不再识别，仅返回正面 OCR 结果（可能为 null）
        return Ok(new
        {
            done = true,
            frontUrl = session.Front?.Url,
            frontKey = session.Front?.Key,
            backUrl = session.Back?.Url,
            backKey = session.Back?.Key,
            ocr = session.FrontOcr
        });
    }

    /// <summary>
    /// 获取本机局域网 IP，供手机扫码访问。
    /// 优先选择物理网卡（排除 VMware/VirtualBox/Hyper-V/WSL/VPN 等虚拟网卡），
    /// 避免多网卡环境（虚拟机、VPN、Docker）下拿到错误的 IP 导致手机无法访问。
    /// </summary>
    private static string GetLanIp()
    {
        foreach (var ni in NetworkInterface.GetAllNetworkInterfaces())
        {
            if (ni.OperationalStatus != OperationalStatus.Up) continue;
            if (IsVirtualAdapter(ni)) continue;
            foreach (var ua in ni.GetIPProperties().UnicastAddresses)
            {
                if (ua.Address.AddressFamily != AddressFamily.InterNetwork) continue;
                var ip = ua.Address.ToString();
                if (ip.StartsWith("192.168.") || ip.StartsWith("10.") || ip.StartsWith("172."))
                    return ip;
            }
        }

        // 兜底：物理网卡找不到时，在虚拟网卡里再找一次
        foreach (var ni in NetworkInterface.GetAllNetworkInterfaces())
        {
            if (ni.OperationalStatus != OperationalStatus.Up) continue;
            foreach (var ua in ni.GetIPProperties().UnicastAddresses)
            {
                if (ua.Address.AddressFamily != AddressFamily.InterNetwork) continue;
                var ip = ua.Address.ToString();
                if (ip.StartsWith("192.168.") || ip.StartsWith("10.") || ip.StartsWith("172."))
                    return ip;
            }
        }
        return "127.0.0.1";
    }

    /// <summary>根据网卡描述判断是否为虚拟/隧道/环回网卡</summary>
    private static bool IsVirtualAdapter(NetworkInterface ni)
    {
        var desc = (ni.Description ?? "").ToLowerInvariant();
        return desc.Contains("virtual") || desc.Contains("vmware") || desc.Contains("virtualbox")
            || desc.Contains("hyper-v") || desc.Contains("tunnel") || desc.Contains("loopback")
            || desc.Contains("docker") || desc.Contains("wsl") || desc.Contains("tailscale")
            || desc.Contains("zerotier") || desc.Contains("vpn") || desc.Contains("tap-")
            || desc.Contains("tun-") || desc.Contains("hamachi");
    }
}