#!/bin/bash

export PLATFORM

has() {
    which "$1" >/dev/null 2>&1
    return $?
}

ink() {
    if [ "$#" -eq 0 -o "$#" -gt 2 ]; then
        return 1
    fi

    local open="\033["
    local close="${open}0m"
    local black="0;30m"
    local red="1;31m"
    local green="1;32m"
    local yellow="1;33m"
    local blue="1;34m"
    local purple="1;35m"
    local cyan="1;36m"
    local gray="0;37m"
    local white="$close"

    local text="$1"
    local color="$close"

    if [ "$#" -eq 2 ]; then
        text="$2"
        case "$1" in
            black | red | green | yellow | blue | purple | cyan | gray | white)
                eval color="\$$1"
                ;;
        esac
    fi

    printf "${open}${color}${text}${close}"
}

log() {
    if [ "$#" -eq 0 -o "$#" -gt 2 ]; then
        return 1
    fi

    local color=
    local text="$2"

    case "$1" in
        TITLE)
            color=yellow
            ;;
        ERROR | WARN)
            color=red
            ;;
        INFO)
            color=green
            ;;
        SUCCESS)
            color=green
            ;;
        *)
            text="$1"
    esac

    timestamp() {
        ink gray "["
        ink purple "$(date +%H:%M:%S)"
        ink gray "] "
    }

    timestamp; ink "$color" "$text"; echo
}

ok() {
    log SUCCESS "$1"
}

die() {
    log ERROR "$1" 1>&2
}

lower() {
    if [ $# -eq 0 ]; then
        cat <&0
    elif [ $# -eq 1 ]; then
        if [ -f "$1" -a -r "$1" ]; then
            cat "$1"
        else
            echo "$1"
        fi
    else
        return 1
    fi | tr "[:upper:]" "[:lower:]"
}

ostype() {
    uname | lower
}

# os_detect export the PLATFORM variable as you see fit
os_detect() {
    export PLATFORM
    case "$(ostype)" in
        *'linux'*)  PLATFORM='linux'   ;;
        *'darwin'*) PLATFORM='darwin'  ;;
        *'bsd'*)    PLATFORM='bsd'     ;;
        *)          PLATFORM='unknown' ;;
    esac
}

extract() {
    if [ -f "$1" ] ; then
        case "$1" in
            *.tar.bz2) tar xvjf   "$1" ;;
            *.tar.gz)  tar xvzf   "$1" ;;
            *.bz2)     bunzip2    "$1" ;;
            *.rar)     unrar x    "$1" ;;
            *.gz)      gunzip     "$1" ;;
            *.tar)     tar xvf    "$1" ;;
            *.tbz2)    tar xvjf   "$1" ;;
            *.tgz)     tar xvzf   "$1" ;;
            *.zip)     unzip      "$1" ;;
            *.Z)       uncompress "$1" ;;
            *.7z)      7z x       "$1" ;;
            *)         return 1        ;;
        esac
    else
        echo "missing file" 1>&2
        return 1
    fi
}

check_dependencies() {
    local err
    err=0

    sleep 1

    if ! has "wget"; then
        err=1
        die "wget: not found"
    fi

    if ! has "curl"; then
        err=1
        die "wget: not found"
    fi

    if [ "$err" -ne 0 ]; then
        exit 1
    fi
}

main() {
    log TITLE "== Bootstraping enhancd =="

    # check dependencies
    check_dependencies

    log INFO "Installing dependencies..."
    sleep 1

    # include blank $L and check user/repo
    echo "$L" | grep -q "^[A-Za-z0-9_-]\+/[A-Za-z0-9_-]\+$"
    if [ $? -ne 0 ]; then
        die "sets the L environment variable to the repository URL (username/reponame) you want to install"
        exit 1
    fi

    USER="$(echo "$L" | awk -F"/" '{print $1}')"
    REPO="$(echo "$L" | awk -F"/" '{print $2}')"

    # detect os
    os_detect
    cd /tmp

    local releases i path bin re ok

    # Same as
    # curl --fail -X GET https://api.github.com/repos/b4b4r07/gomi/releases/latest | jq '.assets[0].browser_download_url' | xargs curl -L -O
    # http://stackoverflow.com/questions/24987542/is-there-a-link-to-github-for-downloading-a-file-in-the-latest-release-of-a-repo
    # http://stackoverflow.com/questions/18384873/how-to-list-the-releases-of-a-repository
    # http://stackoverflow.com/questions/5207269/releasing-a-build-artifact-on-github
    #if has "jq"; then
    #    curl --fail -X GET https://api.github.com/repos/b4b4r07/gomi/releases/latest | jq -r '.assets[].browser_download_url' | grep $PLATFORM | wget -i -
    #fi

    log INFO "Getting releases information and scraping it...\n"
    releases="$(curl -sSf -L https://github.com/"${USER}"/"${REPO}"/releases/latest \
        | egrep -o '/'"${USER}"'/'"${REPO}"'/releases/download/[^"]*' \
        | grep $PLATFORM
    )"

    # github releases not available
    if [ -z "$releases" ]; then
        die "URL that can be used as Github releases was not found"
        exit 1
    fi

    # download github releases for USER's platform
    log INFO "downloading $releases\n"
    echo "$releases" | wget --base=http://github.com/ -i -

    # Main processing
    #
    # check machine architecture
    ok=0
    re=$(uname -m | grep -o "..$")
    for i in $releases
    do
        bin="$(basename "$i" | grep "$re")"
        if [ -n "$bin" -a -f "$bin" ]; then
            if extract "$bin" 2>/dev/null; then
                log INFO "extract ${bin}..."
                if [ -f "$REPO" -a -x "$REPO" ]; then
                    # do nothing
                    bin=""
                else
                    dir="$(ls -1 -F | grep "$REPO" | grep "/$" | head)"
                    if [ -z "$dir" ]; then
                        die "$REPO: not found"
                        exit 1
                    fi

                    if [ -f "$dir/$REPO" -a -x "$dir/$REPO" ]; then
                        bin="$dir/$REPO"
                    fi
                fi
            fi

            # Make a copy of REPO and rename to REPO
            cp "$bin" "$REPO" 2>/dev/null
            chmod 755 "$REPO"

            # Find the directory that you can install from $PATH
            for path in ${PATH//:/ }
            do
                log INFO "installing to $path..."
                install -m 0755 "$REPO" "$path" >/dev/null 2>&1
                if [ $? -eq 0 ]; then
                    ok "installed $REPO to $path successfully"
                    ok=1
                    break
                fi
            done

            # One binary is enough to complete this installation
            break
        fi
    done

    # no binary can execute
    if [ $ok -eq 0 ]; then
        die "there is no binary that can execute on this platform"
        die "or, the all PATHs require sudoer; please add new path to the PATH"
        exit 1
    fi

    # Cleanup!
    # remove the intermediate files
    # thus complete the installation
    for i in $releases
    do
        rm -f "$(basename "$i")"
    done

    # Notification log
    if has "$REPO"; then
        ok "Now finished!"
        # cleanup
        rm -f "$REPO"
    else
        die "$REPO: incomplete or unsuccessful installations"
        echo "please put ./$REPO to somewhere you want" 1>&2
        echo "(on UNIX-ly systems, /usr/local/bin or the like)" 1>&2
        echo "you should run 'mv ./$REPO /usr/local/bin' now" 1>&2
        exit 1
    fi
}

if echo "$-" | grep -q "i"; then
    # -> source a.sh
    return

else
    # three patterns
    # -> cat a.sh | bash
    # -> bash -c "$(cat a.sh)"
    # -> bash a.sh
    if [ -z "$BASH_VERSION" ]; then
        die "This installation requires bash"
        exit 1
    fi

    if [ "$0" = "${BASH_SOURCE:-}" ]; then
        # -> bash a.sh
        exit
    fi

    if [ -n "${BASH_EXECUTION_STRING:-}" ] || [ -p /dev/stdin ]; then
        trap "die 'terminated $0:$LINENO'; exit 1" INT ERR
        # -> cat a.sh | bash
        # -> bash -c "$(cat a.sh)"
        main
    fi
fi