package database

import (
	"database/sql"
	"time"
	"weatherstation/pkg/types"
)

// GetOnlineDevicesCount 获取在线设备数量
func GetOnlineDevicesCount(db *sql.DB) int {
	query := `
		SELECT COUNT(DISTINCT station_id) 
		FROM rs485_weather_data 
		WHERE timestamp > NOW() - INTERVAL '5 minutes'`

	var count int
	if err := db.QueryRow(query).Scan(&count); err != nil {
		return 0
	}
	return count
}

// GetStations 获取所有WH65LP站点列表
func GetStations(db *sql.DB) ([]types.Station, error) {
	query := `
		SELECT DISTINCT s.station_id, 
			COALESCE(s.password, '') as station_name,
			'WH65LP' as device_type,
			COALESCE(MAX(r.timestamp), '1970-01-01'::timestamp) as last_update,
			COALESCE(s.latitude, 0) as latitude,
			COALESCE(s.longitude, 0) as longitude,
			COALESCE(s.name, '') as name,
			COALESCE(s.location, '') as location
		FROM stations s
		LEFT JOIN rs485_weather_data r ON s.station_id = r.station_id
		WHERE s.station_id LIKE 'RS485-%'
		GROUP BY s.station_id, s.password, s.latitude, s.longitude, s.name, s.location
		ORDER BY s.station_id`

	rows, err := db.Query(query)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	var stations []types.Station
	for rows.Next() {
		var station types.Station
		var lastUpdate time.Time
		err := rows.Scan(
			&station.StationID,
			&station.StationName,
			&station.DeviceType,
			&lastUpdate,
			&station.Latitude,
			&station.Longitude,
			&station.Name,
			&station.Location,
		)
		if err != nil {
			continue
		}
		station.LastUpdate = lastUpdate.Format("2006-01-02 15:04:05")
		stations = append(stations, station)
	}

	return stations, nil
}

// GetWeatherData 获取指定站点的历史天气数据
func GetWeatherData(db *sql.DB, stationID string, startTime, endTime time.Time, interval string) ([]types.WeatherPoint, error) {
	// 构建查询SQL（统一风向矢量平均，雨量为累计量的正增量求和）
	var query string
	var intervalStr string
	switch interval {
	case "10min":
		intervalStr = "10 minutes"
	case "30min":
		intervalStr = "30 minutes"
	default: // 1hour
		intervalStr = "1 hour"
	}
	query = buildWeatherDataQuery(intervalStr)

	rows, err := db.Query(query, intervalStr, stationID, startTime, endTime)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	var points []types.WeatherPoint
	for rows.Next() {
		var point types.WeatherPoint
		err := rows.Scan(
			&point.DateTime,
			&point.Temperature,
			&point.Humidity,
			&point.Pressure,
			&point.WindSpeed,
			&point.WindDir,
			&point.Rainfall,
			&point.Light,
			&point.UV,
		)
		if err != nil {
			continue
		}
		points = append(points, point)
	}

	return points, nil
}

// GetSeriesFrom10Min 基于10分钟聚合表返回 10m/30m/1h 数据（风向向量平均、降雨求和、加权平均）
func GetSeriesFrom10Min(db *sql.DB, stationID string, startTime, endTime time.Time, interval string) ([]types.WeatherPoint, error) {
	var query string
	switch interval {
	case "10min":
		query = `
			SELECT 
				to_char(bucket_start, 'YYYY-MM-DD HH24:MI:SS') AS date_time,
				ROUND(temp_c_x100/100.0, 2) AS temperature,
				ROUND(humidity_pct::numeric, 2) AS humidity,
				ROUND(pressure_hpa_x100/100.0, 2) AS pressure,
				ROUND(wind_speed_ms_x1000/1000.0, 3) AS wind_speed,
				ROUND(wind_dir_deg::numeric, 2) AS wind_direction,
				ROUND(rain_10m_mm_x1000/1000.0, 3) AS rainfall,
				ROUND(solar_wm2_x100/100.0, 2) AS light,
				ROUND(uv_index::numeric, 2) AS uv
			FROM rs485_weather_10min
			WHERE station_id = $1 AND bucket_start >= $2 AND bucket_start <= $3
			ORDER BY bucket_start`
	case "30min":
		query = buildAggFrom10MinQuery("30 minutes")
	default: // 1hour
		query = buildAggFrom10MinQuery("1 hour")
	}

	rows, err := db.Query(query, stationID, startTime, endTime)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	var points []types.WeatherPoint
	for rows.Next() {
		var p types.WeatherPoint
		if err := rows.Scan(&p.DateTime, &p.Temperature, &p.Humidity, &p.Pressure, &p.WindSpeed, &p.WindDir, &p.Rainfall, &p.Light, &p.UV); err != nil {
			continue
		}
		points = append(points, p)
	}
	return points, nil
}

// buildAggFrom10MinQuery 返回从10分钟表再聚合的SQL（interval 支持 '30 minutes' 或 '1 hour'）
func buildAggFrom10MinQuery(interval string) string {
	return `
	WITH base AS (
		SELECT * FROM rs485_weather_10min
		WHERE station_id = $1 AND bucket_start >= $2 AND bucket_start <= $3
	), g AS (
		SELECT
			date_trunc('hour', bucket_start) + floor(extract(epoch from (bucket_start - date_trunc('hour', bucket_start)))/extract(epoch from '` + interval + `'::interval)) * '` + interval + `'::interval AS grp,
			SUM(temp_c_x100 * sample_count)::bigint        AS w_temp,
			SUM(humidity_pct * sample_count)::bigint       AS w_hum,
			SUM(pressure_hpa_x100 * sample_count)::bigint  AS w_p,
			SUM(solar_wm2_x100 * sample_count)::bigint     AS w_solar,
			SUM(uv_index * sample_count)::bigint           AS w_uv,
			SUM(wind_speed_ms_x1000 * sample_count)::bigint AS w_ws,
			MAX(wind_gust_ms_x1000)                        AS gust_max,
			SUM(sin(radians(wind_dir_deg)) * sample_count)::double precision AS sin_sum,
			SUM(cos(radians(wind_dir_deg)) * sample_count)::double precision AS cos_sum,
			SUM(rain_10m_mm_x1000)                         AS rain_sum,
			SUM(sample_count)                              AS n_sum
		FROM base
		GROUP BY 1
	)
	SELECT
		to_char(grp, 'YYYY-MM-DD HH24:MI:SS') AS date_time,
		ROUND((w_temp/NULLIF(n_sum,0))/100.0, 2)   AS temperature,
		ROUND((w_hum/NULLIF(n_sum,0))::numeric, 2) AS humidity,
		ROUND((w_p/NULLIF(n_sum,0))/100.0, 2)      AS pressure,
		ROUND((w_ws/NULLIF(n_sum,0))/1000.0, 3)    AS wind_speed,
		ROUND((CASE WHEN degrees(atan2(sin_sum, cos_sum)) < 0
			THEN degrees(atan2(sin_sum, cos_sum)) + 360
			ELSE degrees(atan2(sin_sum, cos_sum)) END)::numeric, 2) AS wind_direction,
		ROUND((rain_sum/1000.0)::numeric, 3)       AS rainfall,
		ROUND((w_solar/NULLIF(n_sum,0))/100.0, 2)  AS light,
		ROUND((w_uv/NULLIF(n_sum,0))::numeric, 2)  AS uv
	FROM g
	ORDER BY grp`
}

// buildWeatherDataQuery 构建天气数据查询SQL
func buildWeatherDataQuery(interval string) string {
	return `
		WITH base AS (
			SELECT 
				date_trunc('hour', timestamp) + 
				(floor(date_part('minute', timestamp) / extract(epoch from $1::interval) * 60) * $1::interval) as time_group,
				timestamp as ts,
				temperature, humidity, pressure, wind_speed, wind_direction, rainfall, light, uv
			FROM rs485_weather_data
			WHERE station_id = $2 AND timestamp BETWEEN $3 AND $4
		),
		rain_inc AS (
			SELECT time_group, GREATEST(rainfall - LAG(rainfall) OVER (PARTITION BY time_group ORDER BY ts), 0) AS inc
			FROM base
		),
		rain_sum AS (
			SELECT time_group, SUM(inc) AS rainfall
			FROM rain_inc
			GROUP BY time_group
		),
		grouped_data AS (
			SELECT 
				time_group,
				AVG(temperature) as temperature,
				AVG(humidity) as humidity,
				AVG(pressure) as pressure,
				AVG(wind_speed) as wind_speed,
				DEGREES(ATAN2(AVG(SIN(RADIANS(wind_direction))), AVG(COS(RADIANS(wind_direction))))) AS wind_direction_raw,
				AVG(light) as light,
				AVG(uv) as uv
			FROM base
			GROUP BY time_group
		)
		SELECT 
			to_char(g.time_group, 'YYYY-MM-DD HH24:MI:SS') as date_time,
			ROUND(g.temperature::numeric, 2) as temperature,
			ROUND(g.humidity::numeric, 2) as humidity,
			ROUND(g.pressure::numeric, 2) as pressure,
			ROUND(g.wind_speed::numeric, 2) as wind_speed,
			ROUND((CASE WHEN g.wind_direction_raw < 0 THEN g.wind_direction_raw + 360 ELSE g.wind_direction_raw END)::numeric, 2) AS wind_direction,
			ROUND(COALESCE(r.rainfall, 0)::numeric, 3) as rainfall,
			ROUND(g.light::numeric, 2) as light,
			ROUND(g.uv::numeric, 2) as uv
		FROM grouped_data g
		LEFT JOIN rain_sum r ON r.time_group = g.time_group
		ORDER BY g.time_group`
}