#!/usr/bin/env nu
# Compare one shell script with bash. Keep both streams and exact exit codes.
def main [host: path, shell: path] {
    let base = '/tmp/s2-shell/comparison'
    mkdir $base
    for name in [native guest] {
        let root = ($base | path join $name)
        mkdir ($root | path join work sub) ($root | path join other) ($root | path join bin) ($root | path join dev)
        "alpha\n" | save -f ($root | path join work f)
        "one\ntwo\n" | save -f ($root | path join work file)
        '' | save -f ($root | path join work a.txt)
        '' | save -f ($root | path join work b.txt)
        "before\n" | save -f ($root | path join work log)
        '' | save -f ($root | path join dev 'null')
        for tool in [cat tr ls wc yes head] {
            cp --force ($env.FILE_PWD | path join userland target wasm32-wasip2 release s2-userland.wasm) ($root | path join bin $tool)
        }
    }
    let script = (open --raw ($env.FILE_PWD | path join corpus.sh))
    let native_root = ($base | path join native)
    let native = (do { cd $native_root; ^bash --noprofile --norc -c $script } | complete)
    let stdout = ($native.stdout | str replace --all $native_root '')
    $stdout | save -f ($base | path join native.stdout)
    $native.stderr | save -f ($base | path join native.stderr)
    print $'native exit=($native.exit_code)'
    let start = (date now)
    let guest = (^$host ($base | path join guest) $shell -c $script | complete)
    print $'guest elapsed=((date now) - $start)'
    $guest.stdout | save -f ($base | path join guest.stdout)
    $guest.stderr | save -f ($base | path join guest.stderr)
    print $'guest exit=($guest.exit_code)'
    print $'equal stdout=($stdout == $guest.stdout)'
    print '--- native stdout ---'
    print $stdout
    print '--- guest stdout ---'
    print $guest.stdout
    print '--- guest stderr ---'
    print $guest.stderr
    if $native.exit_code != $guest.exit_code or $stdout != $guest.stdout {
        error make {msg: 'shell comparison failed'}
    }
}