Wpized install script

#!/bin/sh

SCRIPT_NAME="wpized"
BASE_NAME="wpized_base"

# Location where wpized base is located.
# When there's an update, the compressed file in this URL must be updated.
# @TODO By using automatic build file, i.e Github, we can add VERSION constant
# and append it as suffix of URL_DOWNLOAD.
WPIZED_FILE="wpized_base.tar.gz"
URL_DOWNLOAD="http://my.dev/$WPIZED_FILE"
UNAME=`uname`
if [ "$UNAME" != "Linux" -a "$UNAME" != "Darwin" ] ; then
    echo "Your OS is NOT supported yet."
    exit 1
fi

set -e
trap "echo Installation failed." EXIT

if [ "$UNAME" = "Darwin" ] ; then
    # OSX

    # Path where wpized script and wpized-base will be copied into.
    PARENT_PATH="/usr/local"
    INSTALL_PATH="/usr/local/$BASE_NAME"

    # Check if wpized is already installed.
    if [ -e "$INSTALL_PATH" ] ; then
        echo "Updating $BASE_NAME in $INSTALL_PATH"
    else
        echo "Installing $BASE_NAME in $INSTALL_PATH"
    fi

    # If PARENT_PATH doesn't exist or isn't writeable, fix it with sudo.
    if [ ! -d "$PARENT_PATH" ] ; then
        echo
        echo "$PARENT_PATH does not exist. Creating it with 'sudo mkdir'."
        echo "This may prompt for your password."
        echo
        sudo /bin/mkdir "$PARENT_PATH"
        sudo /usr/bin/chgrp admin "$PARENT_PATH"
        sudo /bin/chmod 755 "$PARENT_PATH"
    elif [ ! -w "$PARENT_PATH" -o ! -w "$PARENT_PATH/bin" ] ; then
        echo
        echo "The install script needs to change the permissions on $PARENT_PATH "
        echo "so that administrators can write to it. This may prompt for your password."
        echo
        sudo /usr/bin/chgrp admin "$PARENT_PATH"
        sudo /bin/chmod g+rwx "$PARENT_PATH"
        if [ -d "$PARENT_PATH/bin" ] ; then
            sudo /usr/bin/chgrp admin "$PARENT_PATH/bin"
            sudo /bin/chmod g+rwx "$PARENT/bin"
        fi
    fi

    # Remove old version.
    if [ -e "$INSTALL_PATH" ] ; then
        rm -rf "$INSTALL_PATH"
    fi

    # Make sure INSTALL_PATH exists.
    mkdir -p "$INSTALL_PATH" || true
    if [ ! -d "$INSTALL_PATH" -o ! -w "$INSTALL_PATH" ] ; then
        echo "Can't write to $INSTALL_PATH"
        exit 1
    fi

    # Download and untar.
    echo "... downloading"
    curl --progress-bar $URL_DOWNLOAD | tar -C "$PARENT_PATH" -xzf -

    # Add to path.
    mkdir -p "$PARENT_PATH/bin"
    rm -f "$PARENT_PATH/bin/$SCRIPT_NAME"
    ln -s "$INSTALL_PATH/$SCRIPT_NAME" "$PARENT_PATH/bin/$SCRIPT_NAME"

    if [ ! -e "$INSTALL_PATH/$SCRIPT_NAME" ] ; then
        echo "The install script needs to change the permissions on $INSTALL_PATH/$SCRIPT_NAME "
        echo "so that the script executeable. This may prompt for your password."
        sudo /bin/chmod g+rwx "$INSTALL_PATH/$SCRIPT_NAME"
    fi

elif [ "$UNAME" = "Linux" ] ; then
    # Linux

    download_url() {
        if [ -x "/usr/bin/curl" ] ; then
            /usr/bin/curl -# -O $1
        elif [ -x "/usr/bin/wget" ] ; then
            /usr/bin/wget -q $1
        else
            echo "Unable to install $BASE_NAME: can't find"
        fi
    }

    do_with_root() {
        # Already have root. Just do it.
        if [ `whoami` = "root" ] ; then
            $*
        elif [ -x /bin/sudo -o -x /usr/bin/sudo ] ; then
            echo
            echo "Since this system includes sudo, $BASE_NAME will request root "
            echo "privileges to install. You may be prompted for a password. If "
            echo "you prefer to not use sudo, please re-run this script as root."
            echo "sudo $*"
            sudo $*
        else
            echo "$BASE_NAME requires root privileges to install. Please re-run "
            echo "this script as root."
            exit 1
        fi
    }

    TMP_DIR=`mktemp -d -t wpized-install-XXXXXXX`
    cd "$TMP_DIR"

    # Path where wpized script and wpized-base will be copied into.
    BIN_PATH="/usr/bin"
    PARENT_PATH="/usr/lib"
    INSTALL_PATH="/usr/lib/$BASE_NAME"

    # Download the file.
    download_url $URL_DOWNLOAD
    if [ ! -f "$WPIZED_FILE" ] ; then
        echo "Error: download $WPIZED_FILE in $TMP_DIR failed."
        exit 1
    fi

    # Installing.
    echo "Installing $TMP_DIR/$WPIZED_FILE"
    do_with_root tar -C "$PARENT_PATH" -xzf "$WPIZED_FILE"
    do_with_root rm -f "$BIN_PATH/$SCRIPT_NAME"
    do_with_root ln -s "$INSTALL_PATH/$SCRIPT_NAME" "$BIN_PATH/$SCRIPT_NAME"
fi

cat <<EOF

Wpized installed! To get started fast:
  $ wpized create ~/project_name
Or see the docs at:
  later

EOF

trap - EXIT