package org.broadinstitute.sting.gatk.traversals;

import edu.mit.broad.picard.filter.SamRecordFilter;
import edu.mit.broad.picard.reference.ReferenceSequence;
import edu.mit.broad.picard.sam.SamFileHeaderMerger;
import net.sf.samtools.SAMFileHeader;
import net.sf.samtools.SAMFileReader;
import net.sf.samtools.SAMFileReader.ValidationStringency;
import net.sf.samtools.SAMRecord;
import net.sf.samtools.util.RuntimeIOException;
import org.apache.log4j.Logger;
import org.broadinstitute.sting.gatk.iterators.*;
import org.broadinstitute.sting.gatk.refdata.RefMetaDataTracker;
import org.broadinstitute.sting.gatk.refdata.ReferenceOrderedData;
import org.broadinstitute.sting.gatk.refdata.ReferenceOrderedDatum;
import org.broadinstitute.sting.gatk.walkers.Walker;
import org.broadinstitute.sting.utils.*;
import org.broadinstitute.sting.utils.fasta.FastaSequenceFile2;

import java.io.File;
import java.io.FileNotFoundException;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

public abstract class TraversalEngine {
    // list of reference ordered data objects
    protected List<ReferenceOrderedData<? extends ReferenceOrderedDatum>> rods = null;

    // Iterator over rods
    List<Pair<String, ReferenceOrderedData<? extends ReferenceOrderedDatum>.RODIterator>> rodIters;

    // How strict should we be with SAM/BAM parsing?
    protected ValidationStringency strictness = ValidationStringency.STRICT;

    // Time in milliseconds since we initialized this engine
    protected long startTime = -1;
    protected long lastProgressPrintTime = -1;                // When was the last time we printed our progress?

    // How long can we go without printing some progress info?
    protected long MAX_PROGRESS_PRINT_TIME = 10 * 1000;        // 10 seconds in millisecs

    // Maximum number of reads to process before finishing
    protected long maxReads = -1;

    // Name of the reads file, in BAM/SAM format
    protected File readsFile = null;                          // the name of the reads file
    protected SAMFileReader samReader = null;
    // iterator over the sam records in the readsFile
    protected Iterator<SAMRecord> samReadIter = null;

    // The verifying iterator, it does checking
    protected VerifyingSamIterator verifyingSamReadIter = null;

    // The reference data -- filename, refSeqFile, and iterator
    protected File refFileName = null;                        // the name of the reference file
    //private ReferenceSequenceFile refFile = null;
    protected FastaSequenceFile2 refFile = null;              // todo: merge FastaSequenceFile2 into picard!
    protected ReferenceIterator refIter = null;

    // Progress tracker for the sam file
    protected FileProgressTracker samReadingTracker = null;

    protected boolean DEBUGGING = false;
    protected boolean beSafeP = true;
    protected boolean SORT_ON_FLY = false;
    protected boolean DOWNSAMPLE_BY_FRACTION = false;
    protected boolean DOWNSAMPLE_BY_COVERAGE = false;
    protected boolean FILTER_UNSORTED_READS = false;
    protected boolean walkOverAllSites = false;
    protected int maxOnFlySorts = 100000;
    protected double downsamplingFraction = 1.0;
    protected int downsamplingCoverage = 0;
    protected long N_RECORDS_TO_PRINT = 100000;
    protected boolean THREADED_IO = false;
    protected int THREADED_IO_BUFFER_SIZE = 10000;

    /**
     * our log, which we want to capture anything from this class
     */
    protected static Logger logger = Logger.getLogger(TraversalEngine.class);


    // Locations we are going to process during the traversal
    private ArrayList<GenomeLoc> locs = null;

    // --------------------------------------------------------------------------------------------------------------
    //
    // Setting up the engine
    //
    // --------------------------------------------------------------------------------------------------------------

    /**
     * Creates a new, uninitialized TraversalEngine
     *
     * @param reads SAM/BAM file of reads
     * @param ref   Reference file in FASTA format, assumes a .dict file is also available
     * @param rods  Array of reference ordered data sets
     */
    public TraversalEngine(File reads, File ref, List<ReferenceOrderedData<? extends ReferenceOrderedDatum>> rods) {
        readsFile = reads;
        refFileName = ref;
        this.rods = rods;
    }

    // --------------------------------------------------------------------------------------------------------------
    //
    // Manipulating the underlying engine parameters
    //
    // --------------------------------------------------------------------------------------------------------------
    //public void setRegion(final String reg) { regionStr = regionStr; }
    //public void setTraversalType(final String type) { traversalType = type; }
    public void setStrictness(final ValidationStringency s) {
        strictness = s;
    }

    public void setMaxReads(final int maxReads) {
        this.maxReads = maxReads;
    }

    public void setThreadedIO(final boolean threadedIO) {
        this.THREADED_IO = threadedIO;
    }

    public void setWalkOverAllSites(final boolean walkOverAllSites) {
        this.walkOverAllSites = walkOverAllSites;
    }

    public void setDebugging(final boolean d) {
        DEBUGGING = d;
    }

    public void setSafetyChecking(final boolean beSafeP) {
        if (!beSafeP)
            logger.warn("*** Turning off safety checking, I hope you know what you are doing.  Errors will result in debugging assert failures and other inscrutable messages...");
        this.beSafeP = beSafeP;
    }

    public void setFilterUnsortedReads(final boolean filterUnsorted) {
        if (!filterUnsorted)
            logger.warn("*** Turning on filtering of out of order reads, I *really* hope you know what you are doing, as you are removing data...");
        this.FILTER_UNSORTED_READS = filterUnsorted;
    }

    public void setSortOnFly(final int maxReadsToSort) {
        logger.info("Sorting read file on the fly: max reads allowed is " + maxReadsToSort);
        SORT_ON_FLY = true;
        maxOnFlySorts = maxReadsToSort;
    }

    public void setSortOnFly() { setSortOnFly(100000); }

    public void setDownsampleByFraction(final double fraction) {
        logger.info("Downsampling to approximately " + (fraction * 100.0) + "% of filtered reads");
        DOWNSAMPLE_BY_FRACTION = true;
        downsamplingFraction = fraction;
    }

    public void setDownsampleByCoverage(final int coverage) {
        logger.info("Downsampling to coverage " + coverage);
        DOWNSAMPLE_BY_COVERAGE = true;
        downsamplingCoverage = coverage;
    }

    // --------------------------------------------------------------------------------------------------------------
    //
    // functions for dealing locations (areas of the genome we're traversing over)
    //
    // --------------------------------------------------------------------------------------------------------------

    /**
     * Parses the location string locStr and sets the traversal engine to only process
     * regions specified by the location string.  The string is of the form:
     * Of the form: loc1;loc2;...
     * Where each locN can be:
     * 'chr2', 'chr2:1000000' or 'chr2:1,000,000-2,000,000'
     *
     * @param locStr
     */
    public void setLocation(final String locStr) {
        this.locs = GenomeLoc.parseGenomeLocs(locStr);
    }

    /**
     * Read a file of genome locations to process.
     * regions specified by the location string.  The string is of the form:
     * Of the form: loc1;loc2;...
     * Where each locN can be:
     * 'chr2', 'chr2:1000000' or 'chr2:1,000,000-2,000,000'
     *
     * @param file_name
     */
    public void setLocationFromFile(final String file_name) {

      this.locs = GenomeLoc.IntervalFileToList(file_name);
    }



    public boolean hasLocations() {
        return this.locs != null;
    }

    // --------------------------------------------------------------------------------------------------------------
    //
    // printing
    //
    // --------------------------------------------------------------------------------------------------------------

    /**
     * @param curTime (current runtime, in millisecs)
     * @return true if the maximum interval (in millisecs) has passed since the last printing
     */
    protected boolean maxElapsedIntervalForPrinting(final long curTime) {
        return (curTime - this.lastProgressPrintTime) > MAX_PROGRESS_PRINT_TIME;
    }

    /**
     * Forward request to printProgress
     *
     * @param type
     * @param loc
     */
    public void printProgress(final String type, GenomeLoc loc) {
        printProgress(false, type, loc);
    }

    /**
     * Utility routine that prints out process information (including timing) every N records or
     * every M seconds, for N and M set in global variables.
     *
     * @param mustPrint If true, will print out info, regardless of nRecords or time interval
     * @param type      String to print out describing our atomic traversal type ("read", "locus", etc)
     * @param loc       Current location
     */
    public void printProgress(boolean mustPrint, final String type, GenomeLoc loc) {
        final long nRecords = TraversalStatistics.nRecords;
        final long curTime = System.currentTimeMillis();
        final double elapsed = (curTime - startTime) / 1000.0;
        //System.out.printf("Cur = %d, last print = %d, elapsed=%.2f, nRecords=%d, met=%b%n", curTime, lastProgressPrintTime, elapsed, nRecords, maxElapsedIntervalForPrinting(curTime));

        if (mustPrint || nRecords % N_RECORDS_TO_PRINT == 0 || maxElapsedIntervalForPrinting(curTime)) {
            this.lastProgressPrintTime = curTime;
            final double secsPer1MReads = (elapsed * 1000000.0) / nRecords;
            if (loc != null)
                logger.info(String.format("[PROGRESS] Traversed to %s, processing %,d %s in %.2f secs (%.2f secs per 1M %s)", loc, nRecords, type, elapsed, secsPer1MReads, type));
            else
                logger.info(String.format("[PROGRESS] Traversed %,d %s in %.2f secs (%.2f secs per 1M %s)", nRecords, type, elapsed, secsPer1MReads, type));

            // Currently samReadingTracker will print misleading info if we're not processing the whole file

            // If an index is enabled, file read progress is meaningless because a linear
            // traversal is not being performed.  For now, don't bother printing progress.
            // TODO: Create a sam indexed read tracker that tracks based on percentage through the query.
            if (samReadingTracker != null && this.locs == null)
                logger.info(String.format("[PROGRESS]   -> %s", samReadingTracker.progressMeter()));
        }
    }

    /**
     * Called after a traversal to print out information about the traversal process
     *
     * @param type String describing this type of traversal ("loci", "read")
     * @param sum  The reduce result of the traversal
     * @param <T>  ReduceType of the traversal
     */
    public <T> void printOnTraversalDone(final String type, T sum) {
        printProgress(true, type, null);
        logger.info("Traversal reduce result is " + sum);
        final long curTime = System.currentTimeMillis();
        final double elapsed = (curTime - startTime) / 1000.0;
        logger.info(String.format("Total runtime %.2f secs, %.2f min, %.2f hours%n", elapsed, elapsed / 60, elapsed / 3600));
        logger.info(String.format("Traversal skipped %d reads out of %d total (%.2f%%)",
                    TraversalStatistics.nSkippedReads,
                    TraversalStatistics.nReads,
                    (TraversalStatistics.nSkippedReads * 100.0) / TraversalStatistics.nReads));
        logger.info(String.format("  -> %d unmapped reads", TraversalStatistics.nUnmappedReads));
        logger.info(String.format("  -> %d non-primary reads", TraversalStatistics.nNotPrimary));
        logger.info(String.format("  -> %d reads with bad alignments", TraversalStatistics.nBadAlignments));
        logger.info(String.format("  -> %d reads with indels", TraversalStatistics.nSkippedIndels));
    }

    // --------------------------------------------------------------------------------------------------------------
    //
    // Initialization
    //
    // --------------------------------------------------------------------------------------------------------------

    /**
     * Initialize the traversal engine.  After this point traversals can be run over the data
     *
     * @return true on success
     */
    public boolean initialize() {
        lastProgressPrintTime = startTime = System.currentTimeMillis();
        initializeReference();
        // Initial the reference ordered data iterators
        initializeRODs();

        return true;
    }

    protected Iterator<SAMRecord> initializeReads() {
        samReader = initializeSAMFile(readsFile);
        return WrapReadsIterator(getReadsIterator(samReader), true);
    }

    protected Iterator<SAMRecord> getReadsIterator(final SAMFileReader samReader) {
        // If the file has an index, querying functions are available.  Use them if possible...
        if ( samReader == null && readsFile.toString().endsWith(".list") ) {
            SAMFileHeader.SortOrder SORT_ORDER = SAMFileHeader.SortOrder.coordinate;

            List<SAMFileReader> readers = new ArrayList<SAMFileReader>();
            try {
                for ( String fileName : new xReadLines(readsFile) ) {
                    SAMFileReader reader = initializeSAMFile(new File(fileName));
                    readers.add(reader);
                }

                SamFileHeaderMerger headerMerger = new SamFileHeaderMerger(readers, SORT_ORDER);
                return new MergingSamRecordIterator2(headerMerger);
            }
            catch ( FileNotFoundException e ) {
                logger.fatal("Couldn't open file in sam file list: " + readsFile);
            }
        }
        //if (samReader.hasIndex()) {
        //    return new SamQueryIterator(samReader, locs);
        //} else {
        return samReader.iterator();
        //}
    }

    protected Iterator<SAMRecord> WrapReadsIterator( final Iterator<SAMRecord> rawIterator, final boolean enableVerification ) {
        Iterator<SAMRecord> wrappedIterator = rawIterator;

        // NOTE: this (and other filtering) should be done before on-the-fly sorting
        //  as there is no reason to sort something that we will end of throwing away
        if (DOWNSAMPLE_BY_FRACTION)
            wrappedIterator = new DownsampleIterator(wrappedIterator, downsamplingFraction);

        if (SORT_ON_FLY)
            wrappedIterator = new SortSamIterator(wrappedIterator, maxOnFlySorts);

        if (beSafeP && enableVerification)
            wrappedIterator = new VerifyingSamIterator(wrappedIterator);

        if (THREADED_IO) {
            logger.info(String.format("Enabling threaded I/O with buffer of %d reads", THREADED_IO_BUFFER_SIZE));
            wrappedIterator = new ThreadedIterator<SAMRecord>(wrappedIterator, THREADED_IO_BUFFER_SIZE);
        }

        return wrappedIterator;
    }

    protected SAMFileReader initializeSAMFile(final File samFile) {
        // todo: fixme, this is a hack to try out dynamic merging
        if ( samFile.toString().endsWith(".list") ) {
            return null;
            // todo: omg, this is just scary, just it's just for testing purposes.  fix with the new DataSource system
        } else {
            SAMFileReader samReader = new SAMFileReader(samFile, true);
            samReader.setValidationStringency(strictness);

            final SAMFileHeader header = samReader.getFileHeader();
            logger.info(String.format("Sort order is: " + header.getSortOrder()));

            return samReader;
        }
    }

    /**
     * Prepare the reference for stream processing
     */
    protected void initializeReference() {
        if (refFileName != null) {
            //this.refFile = ReferenceSequenceFileFactory.getReferenceSequenceFile(refFileName);
            this.refFile = new FastaSequenceFile2(refFileName);   // todo: replace when FastaSequenceFile2 is in picard
            this.refIter = new ReferenceIterator(this.refFile);
            if (!GenomeLoc.setupRefContigOrdering(this.refFile)) {
              // We couldn't process the reference contig ordering, fail since we need it
                Utils.scareUser(String.format("We couldn't load the contig dictionary associated with %s.  At the current time we require this dictionary file to efficiently access the FASTA file.  Please use /seq/software/picard/current/bin/CreateSequenceDictionary.jar to create a sequence dictionary for your file", refFileName));
            }
        }
    }

    /**
     * Prepare the list of reference ordered data iterators for each of the rods
     *
     * @return A list of ROD iterators for getting data from each ROD
     */
    protected void initializeRODs() {
        // set up reference ordered data
        rodIters = new ArrayList<Pair<String, ReferenceOrderedData<? extends ReferenceOrderedDatum>.RODIterator>>();
        for (ReferenceOrderedData<? extends ReferenceOrderedDatum> data : rods) {
            rodIters.add(new Pair<String, ReferenceOrderedData<? extends ReferenceOrderedDatum>.RODIterator>(data.getName(), data.iterator()));
        }
    }

    /**
     * An inappropriately placed testing of reading the reference
     */
    protected void testReference() {
        while (true) {
            ReferenceSequence ref = refFile.nextSequence();
            logger.debug(String.format("%s %d %d", ref.getName(), ref.length(), System.currentTimeMillis()));
            printProgress(true, "loci", new GenomeLoc("foo", 1));
        }
    }

    // --------------------------------------------------------------------------------------------------------------
    //
    // shutdown
    //
    // --------------------------------------------------------------------------------------------------------------

    public boolean shutdown() {
        // todo: actually shutdown the resources
        
        return true;
    }


    // --------------------------------------------------------------------------------------------------------------
    //
    // dealing with reference ordered data
    //
    // --------------------------------------------------------------------------------------------------------------

    /**
     * Builds a list of the reference ordered datum at loc from each of the iterators.  This function
     * assumes you are accessing the data in order.  You can't use this function for random access.  Each
     * successive call moves you along the file, consuming all data before loc.
     *
     * @param loc      The location to get the rods at
     * @return A list of ReferenceOrderDatum at loc.  ROD without a datum at loc will be null in the list
     */
    protected RefMetaDataTracker getReferenceOrderedDataAtLocus(final GenomeLoc loc) {
        RefMetaDataTracker tracks = new RefMetaDataTracker();
        for (Pair<String, ReferenceOrderedData<? extends ReferenceOrderedDatum>.RODIterator> pair : rodIters) {
            String name = pair.getFirst();
            tracks.bind(name, pair.getSecond().seekForward(loc));
        }
        return tracks;
    }

    // --------------------------------------------------------------------------------------------------------------
    //
    // processing
    //
    // --------------------------------------------------------------------------------------------------------------

    public <M, T> T traverse(Walker<M, T> walker) {
        ArrayList<GenomeLoc> l = new ArrayList<GenomeLoc>();
        if ( hasLocations() )
            l = locs;

        return traverse(walker, l);
    }

    public <M, T> T traverse(Walker<M, T> walker, ArrayList<GenomeLoc> locations) {
        return null;
    }
    
    // --------------------------------------------------------------------------------------------------------------
    //
    // traversal by loci functions
    //
    // --------------------------------------------------------------------------------------------------------------

    /**
     * Class to filter out un-handle-able reads from the stream.  We currently are skipping
     * unmapped reads, non-primary reads, unaligned reads, and those with indels.  We should
     * really change this to handle indel containing reads.
     */
    class locusStreamFilterFunc implements SamRecordFilter {
        SAMRecord lastRead = null;
        public boolean filterOut(SAMRecord rec) {
            boolean result = false;
            String why = "";
            if (rec.getReadUnmappedFlag()) {
                TraversalStatistics.nUnmappedReads++;
                result = true;
                why = "Unmapped";
            } else if (rec.getNotPrimaryAlignmentFlag()) {
                TraversalStatistics.nNotPrimary++;
                result = true;
                why = "Not Primary";
            } else if (rec.getAlignmentStart() == SAMRecord.NO_ALIGNMENT_START) {
                TraversalStatistics.nBadAlignments++;
                result = true;
                why = "No alignment start";
            }
            else {
                result = false;
            }

            if (result) {
                TraversalStatistics.nSkippedReads++;
                //System.out.printf("  [filter] %s => %b %s", rec.getReadName(), result, why);
            } else {
                TraversalStatistics.nReads++;
            }
            return result;
        }
    }

    public void verifySortOrder(final boolean requiresSortedOrder) {
        if (beSafeP && !SORT_ON_FLY && samReader.getFileHeader().getSortOrder() != SAMFileHeader.SortOrder.coordinate) {
            final String msg = "SAM file is not sorted in coordinate order (according to header) Walker type with given arguments requires a sorted file for correct processing";
            if (requiresSortedOrder || strictness == SAMFileReader.ValidationStringency.STRICT)
                throw new RuntimeIOException(msg);
            else if (strictness == SAMFileReader.ValidationStringency.LENIENT)
                logger.warn(msg);
        }
    }

    public SAMFileReader getSamReader() { return this.samReader; }
}