using System.Net.Http.Headers;
using System.Text;
using ErvProtocol;

namespace ErvCollector.Storage
{
    // InfluxDB v2 라인 프로토콜 기록 (외부 라이브러리 없이 HTTP /api/v2/write)
    //
    // measurement:
    //   erv_global,site=<site>  power,run_mode,auto_state,fan_mode,sub_mode,hood,
    //                           hyst_preset,hyst_pm25,hyst_pm10,hyst_voc,hyst_co2,error_code
    //   erv_room,site=<site>,room=<1..4>  damper,pm25,pm10,voc,co2,air_quality,led_dim,
    //                           load_score,final_volume
    public sealed class InfluxLineWriter : IDisposable
    {
        readonly HttpClient _http = new() { Timeout = TimeSpan.FromSeconds(10) };
        readonly string _writeUrl;

        public event Action<string>? OnError;

        public InfluxLineWriter(string url, string org, string bucket, string token)
        {
            _writeUrl = $"{url.TrimEnd('/')}/api/v2/write" +
                        $"?org={Uri.EscapeDataString(org)}&bucket={Uri.EscapeDataString(bucket)}&precision=ns";
            _http.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Token", token);
        }

        public async Task WriteAsync(string site, StatusRecord s, DateTime nowUtc)
        {
            long ts = ToUnixNanos(nowUtc);
            var sb = new StringBuilder(512);

            // erv_global
            sb.Append("erv_global,site=").Append(site).Append(' ')
              .Append("power=").Append(s.Power).Append("i,")
              .Append("run_mode=").Append(s.RunMode).Append("i,")
              .Append("auto_state=").Append(s.AutoState).Append("i,")
              .Append("fan_mode=").Append(s.FanMode).Append("i,")
              .Append("sub_mode=").Append(s.SubMode).Append("i,")
              .Append("hood=").Append(s.Hood).Append("i,")
              .Append("hyst_preset=").Append(s.HystPreset).Append("i,")
              .Append("hyst_pm25=").Append(s.HystPm25).Append("i,")
              .Append("hyst_pm10=").Append(s.HystPm10).Append("i,")
              .Append("hyst_voc=").Append(s.HystVoc).Append("i,")
              .Append("hyst_co2=").Append(s.HystCo2).Append("i,")
              .Append("error_code=").Append(s.ErrorCode).Append("i,")
              .Append("reset=").Append(s.Reset).Append('i')
              .Append(' ').Append(ts).Append('\n');

            // erv_room (4실)
            for (int r = 0; r < 4; r++)
            {
                var rm = s.Rooms[r];
                sb.Append("erv_room,site=").Append(site).Append(",room=").Append(r + 1).Append(' ')
                  .Append("damper=").Append(rm.Damper).Append("i,")
                  .Append("pm25=").Append(rm.Pm25).Append("i,")
                  .Append("pm10=").Append(rm.Pm10).Append("i,")
                  .Append("voc=").Append(rm.Voc).Append("i,")
                  .Append("co2=").Append(rm.Co2).Append("i,")
                  .Append("air_quality=").Append(rm.AirQuality).Append("i,")
                  .Append("led_dim=").Append(rm.LedDim).Append("i,")
                  .Append("load_score=").Append(rm.LoadScore).Append("i,")
                  .Append("final_volume=").Append(rm.FinalVolume).Append('i')
                  .Append(' ').Append(ts).Append('\n');
            }

            // erv_vsp (9엔트리: 환기1~4, 바이패스, 공청1~4)
            for (int i = 0; i < 9; i++)
            {
                var v = s.Vsp[i];
                sb.Append("erv_vsp,site=").Append(site).Append(",vsp=").Append(VspInfo.Keys[i]).Append(' ')
                  .Append("sa=").Append(v.Sa).Append("i,")
                  .Append("ea=").Append(v.Ea).Append('i')
                  .Append(' ').Append(ts).Append('\n');
            }

            // erv_hyst (프리셋별 임계값: eco/normal/turbo)
            string[] presetKey = { "eco", "normal", "turbo" };
            for (int i = 0; i < 3; i++)
            {
                var h = s.HystTable[i];
                sb.Append("erv_hyst,site=").Append(site).Append(",preset=").Append(presetKey[i]).Append(' ')
                  .Append("pm25=").Append(h.Pm25).Append("i,")
                  .Append("pm10=").Append(h.Pm10).Append("i,")
                  .Append("voc=").Append(h.Voc).Append("i,")
                  .Append("co2=").Append(h.Co2).Append('i')
                  .Append(' ').Append(ts).Append('\n');
            }

            try
            {
                using var content = new StringContent(sb.ToString(), Encoding.UTF8);
                using var resp = await _http.PostAsync(_writeUrl, content);
                if (!resp.IsSuccessStatusCode)
                {
                    string body = await resp.Content.ReadAsStringAsync();
                    OnError?.Invoke($"Influx write HTTP {(int)resp.StatusCode}: {body}");
                }
            }
            catch (Exception ex)
            {
                OnError?.Invoke($"Influx write FAIL: {ex.Message}");
            }
        }

        static long ToUnixNanos(DateTime utc)
        {
            long ticks = utc.ToUniversalTime().Ticks - DateTime.UnixEpoch.Ticks;  // 100ns ticks
            return ticks * 100L;
        }

        public void Dispose() => _http.Dispose();
    }
}