process STAR_GENOMEGENERATE {
    tag "$fasta"
    label 'process_high'

    // Note: 2.7X indices incompatible with AWS iGenomes.
    conda (params.enable_conda ? "bioconda::star=2.7.9a bioconda::samtools=1.13 conda-forge::gawk=5.1.0" : null)
    container "${ workflow.containerEngine == 'singularity' && !task.ext.singularity_pull_docker_container ?
        'https://depot.galaxyproject.org/singularity/mulled-v2-1fa26d1ce03c295fe2fdcf85831a92fbcbd7e8c2:a7908dfb0485a80ca94e4d17b0ac991532e4e989-0' :
        'quay.io/biocontainers/mulled-v2-1fa26d1ce03c295fe2fdcf85831a92fbcbd7e8c2:a7908dfb0485a80ca94e4d17b0ac991532e4e989-0' }"

    input:
    path fasta
    path gtf

    output:
    path "star"         , emit: index
    path "versions.yml" , emit: versions

    script:
    def args = task.ext.args ?: ''
    def args_list = args.tokenize()
    def memory   = task.memory ? "--limitGenomeGenerateRAM ${task.memory.toBytes() - 100000000}" : ''
    if (args_list.contains('--genomeSAindexNbases')) {
        """
        mkdir star
        STAR \\
            --runMode genomeGenerate \\
            --genomeDir star/ \\
            --genomeFastaFiles $fasta \\
            --sjdbGTFfile $gtf \\
            --runThreadN $task.cpus \\
            $memory \\
            $args

        cat <<-END_VERSIONS > versions.yml
        "${task.process}":
            star: \$(STAR --version | sed -e "s/STAR_//g")
            samtools: \$(echo \$(samtools --version 2>&1) | sed 's/^.*samtools //; s/Using.*\$//')
            gawk: \$(echo \$(gawk --version 2>&1) | sed 's/^.*GNU Awk //; s/, .*\$//')
        END_VERSIONS
        """
    } else {
        """
        samtools faidx $fasta
        NUM_BASES=`gawk '{sum = sum + \$2}END{if ((log(sum)/log(2))/2 - 1 > 14) {printf "%.0f", 14} else {printf "%.0f", (log(sum)/log(2))/2 - 1}}' ${fasta}.fai`

        mkdir star
        STAR \\
            --runMode genomeGenerate \\
            --genomeDir star/ \\
            --genomeFastaFiles $fasta \\
            --sjdbGTFfile $gtf \\
            --runThreadN $task.cpus \\
            --genomeSAindexNbases \$NUM_BASES \\
            $memory \\
            $args

        cat <<-END_VERSIONS > versions.yml
        "${task.process}":
            star: \$(STAR --version | sed -e "s/STAR_//g")
            samtools: \$(echo \$(samtools --version 2>&1) | sed 's/^.*samtools //; s/Using.*\$//')
            gawk: \$(echo \$(gawk --version 2>&1) | sed 's/^.*GNU Awk //; s/, .*\$//')
        END_VERSIONS
        """
    }
}