process GATK4_MERGEBAMALIGNMENT {
    tag "$meta.id"
    label 'process_low'

    conda (params.enable_conda ? "bioconda::gatk4=4.2.3.0" : null)
    container "${ workflow.containerEngine == 'singularity' && !task.ext.singularity_pull_docker_container ?
        'https://depot.galaxyproject.org/singularity/gatk4:4.2.3.0--hdfd78af_0' :
        'quay.io/biocontainers/gatk4:4.2.3.0--hdfd78af_0' }"

    input:
    tuple val(meta), path(aligned)
    path  unmapped
    path  fasta
    path  dict

    output:
    tuple val(meta), path('*.bam'), emit: bam
    path  "versions.yml"          , emit: versions

    script:
    def args = task.ext.args ?: ''
    def prefix = task.ext.prefix ?: "${meta.id}"
    """
    gatk MergeBamAlignment \\
        ALIGNED=$aligned \\
        UNMAPPED=$unmapped \\
        R=$fasta \\
        O=${prefix}.bam \\
        $args

    cat <<-END_VERSIONS > versions.yml
    "${task.process}":
        gatk4: \$(echo \$(gatk --version 2>&1) | sed 's/^.*(GATK) v//; s/ .*\$//')
    END_VERSIONS
    """
}