#!/usr/bin/env python

# Executable files.  Please update these to match the installed locations of your tools.
samtools_exe='/seq/dirseq/samtools/current/samtools'
java_exe='/broad/tools/Linux/x86_64/pkgs/jdk_1.6.0_12/bin/java'
R_exe="/broad/tools/apps/R-2.6.0/bin/Rscript"

# Location of the resource files distributed with the recalibration tool.  
# If editing, please end this variable with a trailing slash.
resources='resources/'

# Where does the reference live?
reference_base = resources + 'Homo_sapiens_assembly18'
reference      = reference_base + '.fasta'
reference_dict = reference_base + '.dict'
reference_fai  = reference_base + '.fasta.fai'

# Where does DBSNP live?
dbsnp = resources + 'dbsnp.rod.out'

# Where are the application files required to run the recalibration
gatk = resources + 'gatk/GenomeAnalysisTK.jar'
logistic_regression_script = resources + 'logistic_regression.R'

import sys,os
import LogisticRegressionByReadGroup

def exit(msg,errorcode):
    print msg
    sys.exit(errorcode)

def check_input_file_available(filename,description):
    if not os.access(filename,os.R_OK):
        exit('Unable to access %s %s' % (description,filename),1)

if len(sys.argv) < 3:
    exit('Usage: python RecalQual.py <input bam file> <calibrated output bam file>',1)

# check that the input bam file exists, and that the bam is indexed.
bam = sys.argv[1]
bam_index = bam + '.bai'

check_input_file_available(bam,'reads file')
check_input_file_available(bam_index,'reads index file')

# parse the user's calibration output file requirements
calibrated_bam = sys.argv[2]
calibrated_bam_index = calibrated_bam + '.bai'

# check that the fasta and supporting files are available
check_input_file_available(reference,'reference file')
check_input_file_available(reference_dict,'reference dictionary')
check_input_file_available(reference_fai,'reference index file')

# check that the dbsnp is available
check_input_file_available(dbsnp,'dbsnp file')

# sanity check that the software is available
check_input_file_available(samtools_exe,'samtools')
check_input_file_available(java_exe,'java')
check_input_file_available(R_exe,'R')
check_input_file_available(gatk,'Genome Analysis Toolkit')
check_input_file_available(logistic_regression_script,'logistic regression script')

# make an output directory for temporary files
if not os.path.isdir('output'):
    os.mkdir('output')

# assemble the required program arguments
gatk_base_cmdline = ' '.join((java_exe,'-ea','-jar',gatk,'-R',reference,'--DBSNP',dbsnp,'-l INFO'))
generate_covariates         = ' '.join((gatk_base_cmdline,'-T CountCovariates','-I',bam,'-mqs 40','--OUTPUT_FILEROOT output/initial','--CREATE_TRAINING_DATA','--MIN_MAPPING_QUALITY 1'))
apply_logistic_regression   = ' '.join((gatk_base_cmdline,'-T LogisticRecalibration','-I',bam,'-logisticParams output/linear_regression_results.out','-outputBAM',calibrated_bam))
index_calibrated_bamfile    = ' '.join((samtools_exe,'index',calibrated_bam))

# generate the covariates
print 'generating covariates'
returncode = os.system(generate_covariates)
if returncode != 0:
    exit('Unable to generate covariates',1)

# compute the logistic regression
print 'computing the logistic regression'
LogisticRegressionByReadGroup.compute_logistic_regression('output/initial.covariate_counts.csv','output/linear_regression_results.out',R_exe,logistic_regression_script)

# apply the logistic regression, writing the output data to calibrated_bam
print 'applying the correction to the reads'
returncode = os.system(apply_logistic_regression)
if returncode != 0:
    exit('Unable to apply logistic regression',1)

# index the calibrated bam
print 'indexing the calibrated bam'
returncode = os.system(index_calibrated_bamfile)
if returncode != 0:
    exit('Unable to index calibrated bamfile',1)

print 'Recalibration complete!  Calibrated bam is available here: ' + calibrated_bam