/*
 * This file is part of McIDAS-V
 *
 * Copyright 2007-2023
 * Space Science and Engineering Center (SSEC)
 * University of Wisconsin - Madison
 * 1225 W. Dayton Street, Madison, WI 53706, USA
 * https://www.ssec.wisc.edu/mcidas
 * 
 * All Rights Reserved
 * 
 * McIDAS-V is built on Unidata's IDV and SSEC's VisAD libraries, and
 * some McIDAS-V source code is based on IDV and VisAD source code.  
 * 
 * McIDAS-V is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Lesser Public License as published by
 * the Free Software Foundation; either version 3 of the License, or
 * (at your option) any later version.
 * 
 * McIDAS-V is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser Public License
 * along with this program.  If not, see http://www.gnu.org/licenses.
 */

package edu.wisc.ssec.mcidasv.data;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;

import java.util.ArrayList;
import java.util.List;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Representation of an AXFORM header file.
 */
public class AxformInfo extends HeaderInfo {

    private static final Logger logger = 
        LoggerFactory.getLogger(AxformInfo.class);
    
    /** The url */
    private String dataFile = "";
    private boolean isAxform = false;

    /**
     * Ctor for xml encoding
     */
    public AxformInfo() {}

    /**
     * CTOR
     *
     * @param thisFile File to use. Cannot be {@code null}.
     */
    public AxformInfo(File thisFile) {
        this(thisFile.getAbsolutePath());
    }

    /**
     * CTOR
     *
     * @param filename The filename
     */
    public AxformInfo(String filename) {
        super(filename);
    }

    /**
     * Is the file an AXFORM header file?
     * 
     * @return Whether or not the file is a valid AXFORM header file.
     */
    public boolean isAxformInfoHeader() {
        parseHeader();
        return isAxform;
    }

    /**
     * Which band number is latitude?
     * 
     * @return Always returns {@code 1} for this class.
     */
    public int getLatBandNum() {
        return 1;
    }

    /**
     * Get the latitude grid file.
     *
     * @return Either the latitude grid file or an empty {@code String}.
     */
    public String getLatBandFile() {
        parseHeader();
        List bandFiles = getParameter(NAVFILES, new ArrayList());
        if (bandFiles.size() != 2) {
            return "";
        }
        return (String)(bandFiles.get(0));
    }

    /**
     * Which band number is longitude?
     * 
     * @return Always returns {@code 1} for this class.
     */
    public int getLonBandNum() {
        return 1;
    }

    /**
     * Get the longitude grid file.
     * 
     * @return Either the longitude grid file or an empty {@code String}.
     */
    public String getLonBandFile() {
        parseHeader();
        List bandFiles = getParameter(NAVFILES, new ArrayList());
        if (bandFiles.size() != 2) {
            return "";
        }
        return (String)(bandFiles.get(1));
    }

    /**
     * Parse a potential AXFORM header file.
     */
    protected void parseHeader() {
        if (haveParsed()) return;
        if (!doesExist()) {
            isAxform = false;
            return;
        }

        try {
            BufferedReader br = new BufferedReader(new FileReader(getFilename()));
            int lineNum = 0;
            String line;
            String description = "";
            boolean gotFiles = false;

            List bandNames = new ArrayList();
            List bandFiles = new ArrayList();

            String latFile = "";
            String lonFile = "";
            File thisFile = new File(getFilename());
            String parent = thisFile.getParent();
            if (parent == null) parent=".";

            while ((line = br.readLine()) != null) {
                lineNum++;
                if (line.trim().equals("Space Science & Engineering Center")) {
                    isAxform = true;
                    continue;
                }
                
                if (!isAxform) {
                    break;
                }

                if (line.length() < 80) {
                    if (lineNum > 15) {
                        gotFiles = true;
                    }
                    continue;
                }

                // Process the description from lines 5 and 6
                if (lineNum == 5) {
                    description += line.substring(13, 41).trim();
                } else if (lineNum == 6) {
                    description += " " + line.substring(14, 23).trim() + " " + line.substring(59, 71).trim();
                    setParameter(DESCRIPTION, description);
                }

                // Process the file list starting at line 15
                else if (lineNum >= 15 && !gotFiles) {
                    String parameter = line.substring(0, 13).trim();
                    if (parameter.equals("Header")) {
                        isAxform = true;
                    } else if (parameter.equals("Latitude")) {
                        latFile = parent + "/" + line.substring(66).trim();
                    } else if (parameter.equals("Longitude")) {
                        lonFile = parent + "/" + line.substring(66).trim();
                    } else {
                        setParameter(LINES, Integer.parseInt(line.substring(24, 31).trim()));
                        setParameter(ELEMENTS, Integer.parseInt(line.substring(32, 40).trim()));
                        setParameter(UNIT, parameter);
                        String band = line.substring(19, 23).trim();
                        String format = line.substring(41, 59).trim();
                        logger.trace("looking at format line: {}", format);
                        if (format.indexOf("ASCII") >= 0) {
                            setParameter(DATATYPE, kFormatASCII);
                        } else if (format.indexOf("8 bit") >= 0) {
                            setParameter(DATATYPE, kFormat1ByteUInt);
                        } else if (format.indexOf("16 bit") >= 0) {
                            setParameter(DATATYPE, kFormat2ByteSInt);
                        } else if (format.indexOf("32 bit") >= 0) {
                            setParameter(DATATYPE, kFormat4ByteSInt);
                        }
                        String filename = line.substring(66).trim();
                        filename = parent + "/" + filename;
                        bandFiles.add(filename);
                        bandNames.add("Band " + band);
                    }
                }

                // Look for the missing value, bail when you find it
                else if (gotFiles) {
                    if (line.indexOf("Navigation files missing data value") >= 0) {
                        setParameter(MISSINGVALUE, Float.parseFloat(line.substring(44, 80).trim()));
                        break;
                    }
                }

                setParameter(BANDNAMES, bandNames);
                setParameter(BANDFILES, bandFiles);

                List latlonFiles = new ArrayList();
                latlonFiles.add(latFile);
                latlonFiles.add(lonFile);
                setParameter(NAVFILES, latlonFiles);

            }
            br.close();
        } catch (Exception e) {
            logger.error("Could not parse header!", e);
        }
    }
}