using System;
using System.IO;
using System.Threading.Tasks;
using Kill.Network;
using UnityEngine;

namespace Kill.Video
{
    /// <summary>
    /// 下载 .264 -> 转封装 MP4(Android MediaCodec+MediaMuxer) -> 返回本地 mp4 路径
    /// 不直接控制 VideoPlayer,由调用方拿到路径后自行 Init
    /// </summary>
    public class VideoDownloadPlayService
    {
        /// <summary>
        /// 完整流程:下载 → 转码
        /// </summary>
        /// <param name="url">视频源 url(.264 裸流)</param>
        /// <param name="onDownloadProgress">下载进度回调(0~1)</param>
        /// <param name="onConvertStart">下载完成,即将开始转码(可更新 UI 提示)</param>
        /// <param name="onComplete">(success, mp4Path) success=false 时 mp4Path 为 null/错误信息</param>
        public async Task<bool> DownloadConvertAndPlay(
            string url,
            Action<DownloadProgress> onDownloadProgress,
            Action<string> onConvertStart,
            Action<bool, string> onComplete)
        {
            if (string.IsNullOrEmpty(url))
            {
                onComplete?.Invoke(false, "url is empty");
                return false;
            }

            string mp4Path = VideoCacheManager.GetCachedMp4Path(url);

            // 1) 已缓存(mp4 直接缓存 / h264 转码后缓存),直接返回
            if (File.Exists(mp4Path) && new FileInfo(mp4Path).Length > 0)
            {
                onComplete?.Invoke(true, mp4Path);
                return true;
            }

            // 2a) 链接是 .mp4:直接下载即得,无需转码
            if (!IsH264Url(url))
            {
                SafeDelete(mp4Path);
                HttpResponse<string> respMp4 = null;
                try
                {
                    respMp4 = await NetworkCtrl.Instance.DownloadFile(url, mp4Path, onDownloadProgress);
                }
                catch (Exception e)
                {
                    Debug.LogError("[VideoDownloadPlayService] mp4 download exception: " + e);
                    SafeDelete(mp4Path);
                    onComplete?.Invoke(false, e.Message);
                    return false;
                }

                if (respMp4 == null || !respMp4.IsSuccess || !File.Exists(mp4Path) || new FileInfo(mp4Path).Length <= 0)
                {
                    SafeDelete(mp4Path);
                    onComplete?.Invoke(false, "mp4 download fail: " + (respMp4?.ErrorMessage ?? "unknown"));
                    return false;
                }

                onComplete?.Invoke(true, mp4Path);
                return true;
            }

            // 2b) 链接是 .h264:先下载再转码
            string h264Path = VideoCacheManager.GetTempH264Path(url);
            SafeDelete(h264Path);
            SafeDelete(mp4Path);

            HttpResponse<string> resp = null;
            try
            {
                resp = await NetworkCtrl.Instance.DownloadFile(url, h264Path, onDownloadProgress);
            }
            catch (Exception e)
            {
                Debug.LogError("[VideoDownloadPlayService] download exception: " + e);
                SafeDelete(h264Path);
                onComplete?.Invoke(false, e.Message);
                return false;
            }

            if (resp == null || !resp.IsSuccess || !File.Exists(h264Path))
            {
                SafeDelete(h264Path);
                onComplete?.Invoke(false, "download fail: " + (resp?.ErrorMessage ?? "unknown"));
                return false;
            }

            onConvertStart?.Invoke(h264Path);

            // 3) 转码 .264 -> .mp4(ffmpeg-kit,libx264 重编码)
            bool convertOk = await FFmpegKitBridge.ConvertH264ToMp4Async(h264Path, mp4Path);
            if (!convertOk)
            {
                Debug.LogError("[VideoDownloadPlayService] ffmpeg convert fail");
            }

            #region debug-point vf-2 (调试图: 记录源/产物文件大小 + 生成的 mp4 媒体信息)
            try
            {
                var hi = new FileInfo(h264Path);
                var mi = new FileInfo(mp4Path);
                Debug.Log("[vf-2] h264Size=" + (hi.Exists ? hi.Length.ToString() : "missing")
                    + " mp4Size=" + (mi.Exists ? mi.Length.ToString() : "missing")
                    + " convertOk=" + convertOk);
                if (mi.Exists && mi.Length > 0)
                {
                    #if UNITY_ANDROID && !UNITY_EDITOR
                        FFmpegKitBridge.ProbeMp4Info(mp4Path);
                    #endif
                }

            }
            catch (Exception e) { Debug.LogError("[vf-2] " + e); }
            #endregion

            // 转码完成,删除 .h264 临时文件
            SafeDelete(h264Path);
            // 失败时清理未完成 mp4
            if (!convertOk || !File.Exists(mp4Path))
            {
                SafeDelete(mp4Path);
                onComplete?.Invoke(false, "convert fail");
                return false;
            }

            onComplete?.Invoke(true, mp4Path);
            return true;
        }

        private static void SafeDelete(string p)
        {
            if (string.IsNullOrEmpty(p)) return;
            try { if (File.Exists(p)) File.Delete(p); } catch { }
        }

        /// <summary>判断链接是否为 .h264/.264 裸流(mp4 等其他一律按可直接下载处理)</summary>
        public static bool IsH264Url(string url)
        {
            if (string.IsNullOrEmpty(url)) return false;
            var l = url.ToLowerInvariant();
            return l.EndsWith(".h264") || l.EndsWith(".264", StringComparison.Ordinal);
        }
    }
}