#!/usr/bin/env bash
# Desc: Runs gpg --verify on all .asc, .gpg, and .sig files in specified directory.
# Version: 0.0.1
# Depends: GNU parallel 20210822
# Assumes: File names do not contain newlines.

declare -Ag appRollCall # Associative array for storing app status
declare -Ag fileRollCall # Associative array for storing file status
declare -Ag dirRollCall # Associative array for storing dir status
find_pat_regex=".+\(sig\|asc\|gpg\)$";
find_depth="10";

yell() { echo "$0: $*" >&2; } # print script path and all args to stderr
die() { yell "$*"; exit 111; } # same as yell() but non-zero exit status
must() { "$@" || die "cannot $*"; } # runs args as command, reports args if command fails
checkapp() {
    # Desc: If arg is a command, save result in assoc array 'appRollCall'
    # Usage: checkapp arg1 arg2 arg3 ...
    # Version: 0.1.1
    # Input: global assoc. array 'appRollCall'
    # Output: adds/updates key(value) to global assoc array 'appRollCall'
    # Depends: bash 5.0.3
    local returnState    

    #===Process Args===
    for arg in "$@"; do
	if command -v "$arg" 1>/dev/null 2>&1; then # Check if arg is a valid command
	    appRollCall[$arg]="true";
	    if ! [ "$returnState" = "false" ]; then returnState="true"; fi;
	else
	    appRollCall[$arg]="false"; returnState="false";
	fi;
    done;

    #===Determine function return code===
    if [ "$returnState" = "true" ]; then
	return 0;
    else
	return 1;
    fi;
} # Check that app exists
checkfile() {
    # Desc: If arg is a file path, save result in assoc array 'fileRollCall'
    # Usage: checkfile arg1 arg2 arg3 ...
    # Version: 0.1.2
    # Input: global assoc. array 'fileRollCall'
    # Output: adds/updates key(value) to global assoc array 'fileRollCall';
    # Output: returns 0 if app found, 1 otherwise
    # Depends: bash 5.0.3
    local returnState

    #===Process Args===
    for arg in "$@"; do
	if [ -f "$arg" ]; then
	    fileRollCall["$arg"]="true";
	    if ! [ "$returnState" = "false" ]; then returnState="true"; fi;
        elif [ -z "$arg" ]; then
            fileRollCall["(no name)"]="false"; returnState="false";
	else
	    fileRollCall["$arg"]="false"; returnState="false";
	fi;
    done;
    
    #===Determine function return code===
    if [ "$returnState" = "true" ]; then
	return 0;
    else
	return 1;
    fi;
} # Check that file exists
checkdir() {
    # Desc: If arg is a dir path, save result in assoc array 'dirRollCall'
    # Usage: checkdir arg1 arg2 arg3 ...
    # Version 0.1.2
    # Input: global assoc. array 'dirRollCall'
    # Output: adds/updates key(value) to global assoc array 'dirRollCall';
    # Output: returns 0 if all args are dirs; 1 otherwise
    # Depends: Bash 5.0.3
    local returnState

    #===Process Args===
    for arg in "$@"; do
	if [ -z "$arg" ]; then
	    dirRollCall["(Unspecified Dirname(s))"]="false"; returnState="false";
	elif [ -d "$arg" ]; then
	    dirRollCall["$arg"]="true";
	    if ! [ "$returnState" = "false" ]; then returnState="true"; fi
	else
	    dirRollCall["$arg"]="false"; returnState="false";
	fi
    done
    
    #===Determine function return code===
    if [ "$returnState" = "true" ]; then
	return 0;
    else
	return 1;
    fi
} # Check that dir exists
displayMissing() {
    # Desc: Displays missing apps, files, and dirs
    # Usage: displayMissing
    # Version 1.0.0
    # Input: associative arrays: appRollCall, fileRollCall, dirRollCall
    # Output: stderr: messages indicating missing apps, file, or dirs
    # Output: returns exit code 0 if nothing missing; 1 otherwise
    # Depends: bash 5, checkAppFileDir()
    local missingApps value appMissing missingFiles fileMissing
    local missingDirs dirMissing

    #==BEGIN Display errors==
    #===BEGIN Display Missing Apps===
    missingApps="Missing apps  :";
    #for key in "${!appRollCall[@]}"; do echo "DEBUG:$key => ${appRollCall[$key]}"; done
    for key in "${!appRollCall[@]}"; do
	value="${appRollCall[$key]}";
	if [ "$value" = "false" ]; then
	    #echo "DEBUG:Missing apps: $key => $value";
	    missingApps="$missingApps""$key ";
	    appMissing="true";
	fi;
    done;
    if [ "$appMissing" = "true" ]; then  # Only indicate if an app is missing.
	echo "$missingApps" 1>&2;
    fi;
    unset value;
    #===END Display Missing Apps===

    #===BEGIN Display Missing Files===
    missingFiles="Missing files:";
    #for key in "${!fileRollCall[@]}"; do echo "DEBUG:$key => ${fileRollCall[$key]}"; done
    for key in "${!fileRollCall[@]}"; do
	value="${fileRollCall[$key]}";
	if [ "$value" = "false" ]; then
	    #echo "DEBUG:Missing files: $key => $value";
	    missingFiles="$missingFiles""$key ";
	    fileMissing="true";
	fi;
    done;
    if [ "$fileMissing" = "true" ]; then  # Only indicate if an app is missing.
	echo "$missingFiles" 1>&2;
    fi;
    unset value;
    #===END Display Missing Files===

    #===BEGIN Display Missing Directories===
    missingDirs="Missing dirs:";
    #for key in "${!dirRollCall[@]}"; do echo "DEBUG:$key => ${dirRollCall[$key]}"; done
    for key in "${!dirRollCall[@]}"; do
	value="${dirRollCall[$key]}";
	if [ "$value" = "false" ]; then
	    #echo "DEBUG:Missing dirs: $key => $value";
	    missingDirs="$missingDirs""$key ";
	    dirMissing="true";
	fi;
    done;
    if [ "$dirMissing" = "true" ]; then  # Only indicate if an dir is missing.
	echo "$missingDirs" 1>&2;
    fi;
    unset value;
    #===END Display Missing Directories===

    #==END Display errors==
    #==BEGIN Determine function return code===
    if [ "$appMissing" == "true" ] || [ "$fileMissing" == "true" ] || [ "$dirMissing" == "true" ]; then
	return 1;
    else
	return 0;
    fi
    #==END Determine function return code===
} # Display missing apps, files, dirs
verify_file() {
    # input: arg1: file path
    path_in="$1"

    # Verify sig file
    if gpg --verify "$path_in" 1>&2 2>/dev/random; then
        printf "STATUS:Good sig for:%s\n" "$path_in";
    else
        printf "STATUS:Bad sig for :%s\n" "$path_in";
    fi;
}; # verfiies one gpg file
main() {
    # Check args
    ## Note: Assume a single arg that is a dir
    if [[ ! $# -eq 1 ]]; then die "FATAL:Incorrect number of args (must be 1):$#"; fi;
    if [[ ! -d "$1" ]]; then die "FATAL:Not a dir:$1"; fi;
    
    # Check apps
    if ! checkapp find gpg parallel; then displayMissing; printf "FATAL:Missing apps."; exit 1; fi;

    # Export bash functions (for GNU parallel)
    export -f yell die must verify_file;

    # Generate file list
    list_paths="$( find "$1" -maxdepth "$find_depth" -type f -iregex "$find_pat_regex" )";

    # Verify files
    echo "$list_paths" | parallel --group verify_file '{}';
};  # main program

main "$@";

exit 0;

#    find "$1" -maxdepth "$find_depth" -type f -iregex "find_pat_regex" | parallel if gpg --verify '{}' 2>/dev/random \; then echo "STATUS:Good sig:" '{}' \; else echo "STATUS:Bad sig :" '{}' \; fi\;