#!/usr/bin/env bash
set -e

# COLOURS
red='\033[1;31m'
green='\033[1;32m'
blue='\033[1;34m'
yellow='\033[1;33m'
nc='\033[0m'

# USAGE GUIDE
# displays the help menu if arguments are missing or incorrect
show_help() {
    printf "${blue}usage:${nc} archivectl <command> <arguments>\n\n"
    printf "commands:\n"
    printf "  compress <source> [output]  compresses a file or directory\n"
    printf "  extract <file>              extracts a supported archive\n\n"
    printf "examples:\n"
    printf "  archivectl compress myfolder\n"
    printf "  archivectl compress myfolder data.zip\n"
    printf "  archivectl extract data.tar.gz\n"
    exit 1
}

# COMPRESSION ROUTINE
# handles the creation of new archives
do_compress() {
    if [ -z "$1" ]; then
        printf "${red}error: target missing for compression.${nc}\n"
        exit 1
    fi

    local source_path="${1%/}"
    if [ ! -e "$source_path" ]; then
        printf "${red}error: source '%s' not found.${nc}\n" "$source_path"
        exit 1
    fi

    local output
    if [ -n "$2" ]; then
        output="$2"
    else
        output="${source_path}.tar.gz"
    fi

    printf "${blue}compressing ${yellow}%s${nc} into ${yellow}%s${nc}...\n" "$source_path" "$output"

    case "$output" in
        *.tar.gz | *.tgz) tar -czf "$output" "$source_path" ;;
        *.tar.xz) tar -cJf "$output" "$source_path" ;;
        *.tar.bz2) tar -cjf "$output" "$source_path" ;;
        *.tar) tar -cf "$output" "$source_path" ;;
        *.zip) zip -r "$output" "$source_path" ;;
        *.7z) 7z a "$output" "$source_path" ;;
        *.rar) rar a "$output" "$source_path" ;;
        *)
            printf "${red}error: format not recognised.${nc}\n"
            exit 1
            ;;
    esac

    printf "${green}compression complete.${nc}\n"
    du -h "$output" | awk '{print $1 "  " $2}'
}

# EXTRACTION ROUTINE
# handles the unpacking of existing archives
do_extract() {
    if [ -z "$1" ]; then
        printf "${red}error: target missing for extraction.${nc}\n"
        exit 1
    fi

    local file="$1"
    if [ ! -f "$file" ]; then
        printf "${red}error: file '%s' not found.${nc}\n" "$file"
        exit 1
    fi

    printf "${blue}extracting: ${yellow}%s${nc}...\n" "$file"

    case "$file" in
        *.tar.bz2 | *.tbz2) tar xjf "$file" ;;
        *.tar.gz | *.tgz) tar xzf "$file" ;;
        *.tar.xz) tar xJf "$file" ;;
        *.tar) tar xf "$file" ;;
        *.lzma) unlzma "$file" ;;
        *.bz2) bunzip2 "$file" ;;
        *.rar) unrar x "$file" ;;
        *.gz) gunzip "$file" ;;
        *.zip) unzip "$file" ;;
        *.Z) uncompress "$file" ;;
        *.7z) 7z x "$file" ;;
        *.xz) unxz "$file" ;;
        *.exe) cabextract "$file" ;;
        *)
            printf "${red}error: format not recognised.${nc}\n"
            exit 1
            ;;
    esac

    printf "${green}extraction complete.${nc}\n"
}

# COMMAND ROUTER
# parses the first argument to determine execution path
case "$1" in
    compress)
        do_compress "$2" "$3"
        ;;
    extract)
        do_extract "$2"
        ;;
    *)
        show_help
        ;;
esac