package publicway;

import java.io.FileInputStream;
import java.io.IOException;
import java.util.Properties;

public class Gpstoxuzuobiao {
    private static final double METERS_PER_DEGREE_LAT = 111320.0d;
    
    // 缓存基准站坐标
    private static double cachedBaseLat = 0.0;
    private static double cachedBaseLon = 0.0;
    private static boolean baseStationLoaded = false;

    /**
     * 解析GNGGA数据并转换为XY坐标
     * @param gnggaData $GNGGA数据
     * @return double[]{x, y} 相对坐标，如果解析失败或无基站数据返回null
     */
    public static double[] processGNGGAToXY(String gnggaData) {
        ensureBaseStationLoaded();
        if (!baseStationLoaded) {
            return null;
        }
        return processGNGGAToXY(gnggaData, cachedBaseLat, cachedBaseLon);
    }

    /**
     * 解析GNGGA数据并转换为XY坐标
     * @param gnggaData $GNGGA数据
     * @param baseLat 基准站纬度
     * @param baseLon 基准站经度
     * @return double[]{x, y} 相对坐标
     */
    public static double[] processGNGGAToXY(String gnggaData, double baseLat, double baseLon) {
        if (gnggaData == null || !gnggaData.contains("$GNGGA")) {
            return null;
        }
        
        // 简单的解析逻辑，提取经纬度
        // 格式: $GNGGA,hhmmss.ss,lat,latDir,lon,lonDir,quality,sats,hdop,alt,units,sep,units,age,refID*cs
        
        String[] parts = gnggaData.split(",");
        // 找到$GNGGA的位置
        int index = -1;
        for(int i=0; i<parts.length; i++) {
            if (parts[i].contains("$GNGGA")) {
                index = i;
                break;
            }
        }
        
        // 确保有足够的字段: lat(2), latDir(3), lon(4), lonDir(5)
        if (index == -1 || index + 5 >= parts.length) {
            return null;
        }
        
        String latStr = parts[index + 2];
        String latDir = parts[index + 3];
        String lonStr = parts[index + 4];
        String lonDir = parts[index + 5];
        
        if (latStr.isEmpty() || lonStr.isEmpty()) {
            return null;
        }
        
        double lat = parseDMToDecimal(latStr, latDir);
        double lon = parseDMToDecimal(lonStr, lonDir);
        
        return convertLatLonToLocal(lat, lon, baseLat, baseLon);
    }

    /**
     * 将度分格式(DMM)转换为十进制格式(DD)
     * @param dmm 度分格式字符串 (e.g. "3015.1234")
     * @param direction 方向 (N/S/E/W)
     * @return 十进制经纬度
     */
    public static double parseDMToDecimal(String dmm, String direction) {
        if (dmm == null || dmm.isEmpty()) {
            return 0.0;
        }
        try {
            double val = Double.parseDouble(dmm);
            int degrees = (int) (val / 100);
            double minutes = val - degrees * 100;
            double decimal = degrees + minutes / 60.0;
            if (direction != null && (direction.equalsIgnoreCase("S") || direction.equalsIgnoreCase("W"))) {
                decimal = -decimal;
            }
            return decimal;
        } catch (NumberFormatException e) {
            return 0.0;
        }
    }

    /**
     * 将经纬度转换为相对坐标(XY)
     * @param lat 目标纬度
     * @param lon 目标经度
     * @param baseLat 基准站纬度
     * @param baseLon 基准站经度
     * @return double[]{x, y} (单位: 米)
     */
    public static double[] convertLatLonToLocal(double lat, double lon, double baseLat, double baseLon) {
        double deltaLat = lat - baseLat;
        double deltaLon = lon - baseLon;
        double meanLatRad = Math.toRadians((baseLat + lat) / 2.0);
        double eastMeters = deltaLon * METERS_PER_DEGREE_LAT * Math.cos(meanLatRad);
        double northMeters = deltaLat * METERS_PER_DEGREE_LAT;
        return new double[]{eastMeters, northMeters};
    }
    
    private static void ensureBaseStationLoaded() {
        if (baseStationLoaded) return;
        
        Properties props = new Properties();
        try (FileInputStream input = new FileInputStream("basestation.properties")) {
            props.load(input);
            String coords = props.getProperty("installationCoordinates");
            if (coords != null && !coords.isEmpty() && !"-1".equals(coords)) {
                String[] parts = coords.split(",");
                if (parts.length >= 4) {
                    cachedBaseLat = parseDMToDecimal(parts[0], parts[1]);
                    cachedBaseLon = parseDMToDecimal(parts[2], parts[3]);
                    baseStationLoaded = true;
                }
            }
        } catch (IOException e) {
            // ignore
        }
    }
    
    /**
     * 重新加载基准站信息
     */
    public static void reloadBaseStation() {
        baseStationLoaded = false;
        ensureBaseStationLoaded();
    }
}