#!/bin/bash

if git rev-parse --verify HEAD &>/dev/null; then
    against=HEAD
else
    # Initial commit: diff against an empty tree object
    against=4b825dc642cb6eb9a060e54bf8d69288fbee4904
fi

check_puppet_manifest () {
    local file=$1

    local pp=${workdir}/${file}
    mkdir -p $(dirname ${pp})
    git cat-file blob :0:${file} | sed 's/^import .*/#&/' >${pp}
    trap "rm -f ${pp}" RETURN

    local output=$(puppet apply --noop ${pp} 2>&1)
    if [ $? -ne 0 ] || [ -n "${output}" ]; then
        echo '** Syntax check failed:' >&2
        echo "${output}" >&2
        return 1
    fi

    # Check manifests for exactly one class or define per file.
    case "${file}" in
        modules/*/manifests/*)
            if [[ "$(egrep -c '^(class|define) ' ${file})" != "1" ]]; then
                echo "** Multiple class/defines:" >&2
                egrep -n '^(class|define) ' ${file} >&2
                return 1
            fi
            ;;
    esac

    case "${file}" in
        manifests/site.pp|modules/*/manifests/*) ;;
        *) return
    esac

    if [ -x /usr/bin/pcregrep ]; then
        local wsfail=$({
            # grep -nPT would be nice. grep -P seems broken on gudeploy01.
            # Patterns checked for are (in this order):
            # - leading SPACE
            # - SPACE followed by TAB
            # - TAB followed by SPACE
            # - non-leading TAB (but allow around '#' comment leader)
            # - trailing whitespace
            pcregrep -n -e '^ ' -e ' \t' -e '\t ' -e '[^\t#]\t+(?!#)' -e '\s+$' ${pp}
        })
        if [[ $(wc -l <${pp}) > $(cat -s ${pp}|wc -l) ]]; then
            wsfail+="Excess blank line(s). 'cat -s' is your friend."
        fi
        if [[ -n "${wsfail}" ]]; then
            echo '** Bad whitespace (see Manifest Standards):' >&2
            echo "${wsfail}" >&2
            return 1
        fi
    else
        echo "Missing pcregrep: apt-get install pcregrep" >&2
    fi

    case "${file}" in
        manifests/site.pp|modules/*/manifests/*)
            puppet-lint --no-hard_tabs-check --no-80chars-check ${pp} >&2 | uniq
            ;;
        *)
            return
            ;;
    esac

    return 0
}

# Check a Puppet template.
#
check_puppet_template () {
    local file=$1

    # Beware of 'Syntax OK' message on success.
    local output=$((git cat-file blob :0:${file}|erb -x -P -T -|ruby -c >/dev/null) 2>&1)
    if [[ $? -ne 0 || -n "${output}" ]]; then
        echo '** Syntax check failed:' >&2
        echo "${output}" >&2
        return 1
    fi

    return 0
}

readonly failed=$(mktemp ${TMPDIR:-/tmp}/git.puppet.pre-commit.XXXXXXXXXX)
readonly missing=$(mktemp ${TMPDIR:-/tmp}/git.puppet.pre-commit.XXXXXXXXXX)
readonly parse=$(mktemp ${TMPDIR:-/tmp}/git.puppet.pre-commit.XXXXXXXXXX)
readonly retest=$(mktemp ${TMPDIR:-/tmp}/git.puppet.pre-commit.XXXXXXXXXX)
readonly workdir=$(mktemp -d ${TMPDIR:-/tmp}/git.puppet.pre-commit.XXXXXXXXXX)
trap "rm -f ${failed} ${missing} ${parse} ${retest}; rm -rf ${workdir}" EXIT

error=0
warning=0
for file in $(git diff-index --name-only --diff-filter=AM --cached ${against}); do
    output=""
    rc=0

    case "${file}" in
        manifests/site.pp)
            output=$(check_puppet_manifest ${file} 2>&1); rc=$?;;
        modules/*)

            case "${file}" in
                modules/*/manifests/*)
                    case "${file}" in
                        # FIXME: doing this so the whitespace check happens
                        *.pp) output=$(check_puppet_manifest ${file} 2>&1); rc=$?;;
                    esac
                    ;;
                modules/*/templates/*)
                    output=$(check_puppet_template ${file} 2>&1); rc=$?;;
            esac
            ;;

    esac

    if [[ ${rc} -ne 0 || -n "${output}" ]]; then
        echo "** ${file}" >&2
        echo "${output}" >&2
        if [[ ${file} != *.pp ]]; then
            error=1
        # puppet-lint warnings are acceptable.
        elif [[ -n "$(egrep -v '^WARNING: ' <<<${output})" ]]; then
            error=1
        else
            warning=1
        fi
    fi
done

if [ "$error" -ne 0 ]; then
    echo "** Please correct the above errors." >&2
    exit 1
fi

if [ "$warning" -ne 0 ]; then
    sleep 5
fi

exit 0