#!/bin/bash

DEFAULT_DOCKCROSS_IMAGE=dockcross/linux-armv6

#------------------------------------------------------------------------------
# Helpers
#
err() {
    echo -e >&2 ERROR: $@\\n
}

die() {
    err $@
    exit 1
}

has() {
    # eg. has command update
    local kind=$1
    local name=$2

    type -t $kind:$name | grep -q function
}

#------------------------------------------------------------------------------
# Command handlers
#
command:update-image() {
    docker pull $FINAL_IMAGE
}

help:update-image() {
    echo Pull the latest $FINAL_IMAGE .
}

command:update-script() {
    if cmp -s <( docker run $FINAL_IMAGE ) $0; then
        echo $0 is up to date
    else
        echo -n Updating $0 '... '
        docker run $FINAL_IMAGE > $0 && echo ok
    fi
}

help:update-image() {
    echo Update $0 from $FINAL_IMAGE .
}

command:update() {
    command:update-image
    command:update-script
}

help:update() {
    echo Pull the latest $FINAL_IMAGE, and then update $0 from that.
}

command:help() {
    if [[ $# != 0 ]]; then
        if ! has command $1; then
            err \"$1\" is not an dockcross command
            command:help
        elif ! has help $1; then
            err No help found for \"$1\"
        else
            help:$1
        fi
    else
        cat >&2 <<ENDHELP
Usage: dockcross [options] [--] command [args]

By default, run the given *command* in an dockcross Docker container.

The *options* can be one of:

    --args|-a           Extra args to the *docker run* command
    --image|-i          Docker cross-compiler image to use
    --config|-c         Bash script to source before running this script


Additionally, there are special update commands:

    update-image
    update-script
    update

For update command help use: $0 help <command>
ENDHELP
        exit 1
    fi
}

#------------------------------------------------------------------------------
# Option processing
#
special_update_command=''
while [[ $# != 0 ]]; do
    case $1 in

        --)
            break
            ;;

        --args|-a)
            ARG_ARGS="$2"
            shift 2
            ;;

        --config|-c)
            ARG_CONFIG="$2"
            shift 2
            ;;

        --image|-i)
            ARG_IMAGE="$2"
            shift 2
            ;;
        update|update-image|update-script)
            special_update_command=$1
            break
            ;;
        -*)
            err Unknown option \"$1\"
            command:help
            exit
            ;;

        *)
            break
            ;;

    esac
done

# The precedence for options is:
# 1. command-line arguments
# 2. environment variables
# 3. defaults

# Source the config file if it exists
DEFAULT_DOCKCROSS_CONFIG=~/.dockcross
FINAL_CONFIG=${ARG_CONFIG-${DOCKCROSS_CONFIG-$DEFAULT_DOCKCROSS_CONFIG}}

[[ -f "$FINAL_CONFIG" ]] && source "$FINAL_CONFIG"

# Set the docker image
FINAL_IMAGE=${ARG_IMAGE-${DOCKCROSS_IMAGE-$DEFAULT_DOCKCROSS_IMAGE}}

# Handle special update command
if [ "$special_update_command" != "" ]; then
    case $special_update_command in

        update)
            command:update
            exit $?
            ;;

        update-image)
            command:update-image
            exit $?
            ;;

        update-script)
            command:update-script
            exit $?
            ;;

    esac
fi

# Set the docker run extra args (if any)
FINAL_ARGS=${ARG_ARGS-${DOCKCROSS_ARGS}}

# If we are not running via boot2docker
if [ -z $DOCKER_HOST ]; then
    USER_IDS="-e BUILDER_UID=$( id -u ) -e BUILDER_GID=$( id -g ) -e BUILDER_USER=$( id -un ) -e BUILDER_GROUP=$( id -gn )"
fi

#------------------------------------------------------------------------------
# Now, finally, run the command in a container
#
docker run --rm \
    -v $PWD:/work \
    $USER_IDS \
    $FINAL_ARGS \
    $FINAL_IMAGE "$@"

################################################################################
#
# This image is not intended to be run manually.
#
# To create a dockcross helper script for the
# dockcross/linux-armv7 image, run:
#
# docker run --rm dockcross/linux-armv7 > dockcross-linux-armv7
# chmod +x dockcross-linux-armv7
#
# You may then wish to move the dockcross script to your PATH.
#
################################################################################