package mil.nga.giat.geowave.format.geotools.raster;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.ServiceLoader;

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

import com.beust.jcommander.Parameter;
import com.beust.jcommander.converters.DoubleConverter;

import mil.nga.giat.geowave.adapter.raster.adapter.RasterDataAdapter;
import mil.nga.giat.geowave.adapter.raster.adapter.merge.RasterTileMergeStrategy;
import mil.nga.giat.geowave.core.ingest.spi.IngestFormatOptionProvider;

public class RasterOptionProvider implements
		IngestFormatOptionProvider
{
	// for now, default to no merging
	private static final RasterTileMergeStrategy DEFAULT_MERGE_STRATEGY = null;
	private final static Logger LOGGER = LoggerFactory.getLogger(RasterOptionProvider.class);
	private static Map<String, RasterMergeStrategyProviderSpi> registeredMergeStrategies = null;
	@Parameter(names = "--pyramid", description = "Build an image pyramid on ingest for quick reduced resolution query")
	private final boolean buildPyramid = false;

	@Parameter(names = "--crs", description = "A CRS override for the provided raster file")
	private final String crs = null;

	@Parameter(names = "--histogram", description = "Build a histogram of samples per band on ingest for performing band equalization")
	private final boolean buildHistogream = false;

	@Parameter(names = "--tileSize", description = "Optional parameter to set the tile size stored (default is 256)")
	private final int tileSize = RasterDataAdapter.DEFAULT_TILE_SIZE;

	@Parameter(names = "--coverage", description = "Optional parameter to set the coverage name (default is the file name)")
	private final String coverageName = null;

	@Parameter(names = "--nodata", variableArity = true, description = "Optional parameter to set 'no data' values, if 1 value is giving it is applied for each band, if multiple are given then the first totalNoDataValues/totalBands are applied to the first band and so on, so each band can have multiple differing 'no data' values if needed", converter = DoubleConverter.class)
	private final List<Double> nodata = new ArrayList<>();

	@Parameter(names = "--separateBands", description = "Optional parameter to separate each band into its own coverage name. By default the coverage name will have '_Bn' appended to it where `n` is the band's index.")
	private final boolean separateBands = false;

	@Parameter(names = "--mergeStrategy", description = "Optional parameter to choose a tile merge strategy used for mosaic.  Default behavior will be `none`.  Alternatively 'no-data' will mosaic the most recent tile over previous tiles, except where there are no data values.")
	private final String mergeStrategy = NoMergeStrategyProvider.NAME;

	public RasterOptionProvider() {}

	public boolean isBuildPyramid() {
		return buildPyramid;
	}

	public int getTileSize() {
		return tileSize;
	}

	public boolean isSeparateBands() {
		return separateBands;
	}

	public String getCrs() {
		return crs;
	}

	public String getCoverageName() {
		if ((coverageName == null) || coverageName.trim().isEmpty()) {
			return null;
		}
		return coverageName;
	}

	public boolean isBuildHistogream() {
		return buildHistogream;
	}

	public double[][] getNodata(
			final int numBands ) {
		if (nodata.isEmpty() || (numBands <= 0)) {
			return null;
		}
		final double[][] retVal = new double[numBands][];
		final int nodataPerBand = nodata.size() / numBands;
		if (nodataPerBand <= 1) {
			for (int b = 0; b < numBands; b++) {
				retVal[b] = new double[] {
					nodata.get(Math.min(
							b,
							nodata.size() - 1))
				};
			}
		}
		else {
			for (int b = 0; b < retVal.length; b++) {
				retVal[b] = new double[nodataPerBand];
				for (int i = 0; i < nodataPerBand; i++) {
					retVal[b][i] = nodata.get((b * nodataPerBand) + i);
				}
			}
		}
		return retVal;
	}

	public RasterTileMergeStrategy<?> getMergeStrategy() {
		final Map<String, RasterMergeStrategyProviderSpi> internalMergeStrategies = getRegisteredMergeStrategies();
		if ((mergeStrategy == null) || mergeStrategy.trim().isEmpty()) {
			LOGGER.warn("Merge Strategy not found");
			return DEFAULT_MERGE_STRATEGY;
		}
		final RasterMergeStrategyProviderSpi provider = internalMergeStrategies.get(mergeStrategy);
		if (provider == null) {
			LOGGER.warn("Merge Strategy Provider not found for '" + mergeStrategy + "'");
			return DEFAULT_MERGE_STRATEGY;
		}
		return provider.getStrategy();
	}

	private synchronized Map<String, RasterMergeStrategyProviderSpi> getRegisteredMergeStrategies() {
		if (registeredMergeStrategies == null) {
			registeredMergeStrategies = new HashMap<String, RasterMergeStrategyProviderSpi>();
			final ServiceLoader<RasterMergeStrategyProviderSpi> converters = ServiceLoader
					.load(RasterMergeStrategyProviderSpi.class);
			final Iterator<RasterMergeStrategyProviderSpi> it = converters.iterator();
			while (it.hasNext()) {
				final RasterMergeStrategyProviderSpi converter = it.next();
				registeredMergeStrategies.put(
						converter.getName(),
						converter);
			}
		}
		return registeredMergeStrategies;
	}
}