#!/bin/bash

if [ ${DIB_DEBUG_TRACE:-0} -gt 1 ]; then
    set -x
fi
set -eu
set -o pipefail

# Don't provide any source repositories in environments where they are not allowed
if [ -n "${NO_SOURCE_REPOSITORIES:-}" ]; then
    exit 0
fi

# If the old cache exists, move it to the new name
function make_new_cache(){
    local OLD_CACHE_BASE=$1
    local CACHE_BASE=$2

    # If the old cache name exists, move it to the new cache name
    if [ -e "$OLD_CACHE_BASE" ] ; then
        if [ ! -e "$CACHE_BASE" ] ; then
            mv -n $OLD_CACHE_BASE $CACHE_BASE
        else
            echo "Not replacing new cache location with old cache"
        fi
    fi
}

# Gets repositories or individual files listed in the a repository file
# and places them in the specified destination path.
# The format of the repository file is one or more lines matching
# <name> <type> <destination> <location> [<ref>]
function get_repos_for_element(){
    local REPO_SOURCES=$1
    local CACHE_URL=$TMP_HOOKS_PATH/bin/cache-url

    local REGEX="^([^ ]+) (git|tar|file|package) ?(/[^ ]+)? ?([^ ]+)? ?([^ ]*)$"

    # this can be a rather long list (e.g. caching ~1000 openstack
    # repos), so we make a rough count for progress display
    local COUNT=1
    local REPO_SOURCES_COUNT=$(grep -v '^$\|^\s*\#' $REPO_SOURCES | wc -l)

    while read line; do

        # temporarily turn off globbing '*' (since it may be used as
        # the REPOREF for tarballs) and expand variables
        set -f; line=$(eval echo $line); set +f

        # ignore blank lines and lines beginning in '#'
        [[ "$line" == \#* ]] || [[ -z "$line" ]] && continue

        # rough progress counter
        printf "(%04d / %04d)\n" ${COUNT} ${REPO_SOURCES_COUNT}
        COUNT=$(( COUNT + 1))

        if [[ "$line" =~ $REGEX ]]  ; then
            local REPONAME=${BASH_REMATCH[1]}
            local REPOTYPE=${BASH_REMATCH[2]}
            local REPOPATH=${BASH_REMATCH[3]}
            local REPOLOCATION=${BASH_REMATCH[4]}
            local REPO_ORIG_LOCATION=$REPOLOCATION

            if [ $REPONAME = "tar" -a -z "${BASH_REMATCH[5]:-}" ] ; then
                echo "Warning: Default tarball REPOREF of '*' is deprecated; do not rely on it."
            fi

            # Default of '*' for tar repositories is deprecated; do not rely on it.
            local REPOREF_DEFAULT_TAR=*
            local REPOREF_DEFAULT_GIT=master
            local REPOREF_LOOKUP_DEFAULT=REPOREF_DEFAULT_${REPOTYPE^^}

            local REPOREF=${BASH_REMATCH[5]:-${!REPOREF_LOOKUP_DEFAULT:-}}

            local REPO_DEST=$TMP_MOUNT_PATH$REPOPATH
            local REPO_SUB_DIRECTORY=$(dirname $REPO_DEST)

            # REPOTYPE can be overridden with DIB_REPOTYPE_{name}
            local REPOTYPE_OVERRIDE=DIB_REPOTYPE_${REPONAME//[^A-Za-z0-9]/_}
            REPOTYPE=${!REPOTYPE_OVERRIDE:-$REPOTYPE}

            # REPOLOCATION can be overridden with DIB_REPOLOCATION_{name}
            local REPOLOCATION_OVERRIDE=DIB_REPOLOCATION_${REPONAME//[^A-Za-z0-9]/_}
            REPOLOCATION=${!REPOLOCATION_OVERRIDE:-$REPOLOCATION}

            # REPOREF can be overridden with DIB_REPOREF_{name}
            local REPOREF_OVERRIDE=DIB_REPOREF_${REPONAME//[^A-Za-z0-9]/_}
            REPOREF=${!REPOREF_OVERRIDE:-$REPOREF}

            # Determine a unique cache path for this repo
            CACHE_NAME=$(echo "${REPOTYPE}_${REPOLOCATION}" | sha1sum | awk '{ print $1 }' )
            OLD_CACHE_PATH=${CACHE_BASE}/${CACHE_NAME}
            # Add the repo name to the sha1sum for readability
            CACHE_NAME=${REPONAME//[^A-Za-z0-9]/_}_${CACHE_NAME}
            CACHE_PATH=${CACHE_BASE}/$CACHE_NAME
            make_new_cache $OLD_CACHE_PATH $CACHE_PATH

            # Return if install type is not source
            local INSTALL_TYPE_VAR=DIB_INSTALLTYPE_${REPONAME//[^A-Za-z0-9]/_}
            local INSTALL_TYPE=${!INSTALL_TYPE_VAR:-$DIB_DEFAULT_INSTALLTYPE}
            if [ ! $INSTALL_TYPE = "source" ]; then
                echo "$REPONAME install type not set to source"
                continue
            fi

            case $REPOTYPE in
            git)
                if [ -z "${!REPOLOCATION_OVERRIDE:-""}" -a -n "${DIB_GITREPOBASE:-""}" ] ; then
                    # Transform the current repo base to the new one
                    local NEW_REPOLOCATION=$(echo $REPOLOCATION |\
                        sed "s,^[^:]\+://[^/]\+/\(~[^/]\+\)\?\(.*\)$,${DIB_GITREPOBASE}\2,g")
                    echo "Transformed ${REPOLOCATION} to ${NEW_REPOLOCATION}"
                    REPOLOCATION=$NEW_REPOLOCATION
                    # Also update the cache location
                    CACHE_NAME=$(echo "${REPOTYPE}_${REPOLOCATION}" | sha1sum | awk '{ print $1 }' )
                    CACHE_PATH=~/.cache/image-create/repository-sources/$CACHE_NAME
                fi
                sudo mkdir -p $REPO_SUB_DIRECTORY

                if [ ! -e "$CACHE_PATH" ] ; then
                    echo "Caching $REPONAME from $REPOLOCATION in $CACHE_PATH"
                    git clone -q $REPOLOCATION $CACHE_PATH.tmp
                    mv ${CACHE_PATH}{.tmp,}
                fi

                if [ "$REPOREF" != "*" ] ; then
                    HAS_REF=$(git --git-dir=$CACHE_PATH/.git name-rev $REPOREF 2>/dev/null || true)
                fi
                if [ -z "$DIB_OFFLINE" -o -z "$HAS_REF" ] ; then
                    echo "Updating cache of $REPOLOCATION in $CACHE_PATH with ref $REPOREF"
                    # Copy named refs (which might be outside the usual heads
                    # pattern) - e.g. gerrit
                    if [ "$REPOREF" == "*" ] || ! git --git-dir=$CACHE_PATH/.git fetch -q --prune --update-head-ok $REPOLOCATION \
                            +${REPOREF}:${REPOREF} ; then
                        # Copy all heads from the remote repository - this permits
                        # using a SHA1 object reference so long as the object
                        # reference is reachable from one of the heads. git does
                        # not permit arbitrary sha fetching from remote servers.
                        # This is a separate fetch to the prior one as the prior
                        # one will fail when REPOREF is a SHA1.
                        git --git-dir=$CACHE_PATH/.git fetch -q --prune --update-head-ok $REPOLOCATION \
                            +refs/heads/*:refs/heads/* +refs/tags/*:refs/tags/*
                    fi
                    # Ensure that we have a reference to the revision.
                    if [ "$REPOREF" != "*" ] ; then
                        if ! git --git-dir=$CACHE_PATH/.git rev-parse -q --verify $REPOREF^{commit} > /dev/null; then
                            echo "Failed to find reference to $REPOREF"
                            exit 1
                        fi
                    fi
                fi

                echo "Cloning from $REPONAME cache and applying ref $REPOREF"
                # If the local dir is already used, see if the pertinent details differ
                if [[ -d $REPO_DEST ]]; then
                    DESIRED="$(sudo git --git-dir=$REPO_DEST/.git config remote.origin.url)"
                    if [[ "$CACHE_PATH" != "$DESIRED" ]]; then
                        echo "REPOLOCATIONS don't match ("$CACHE_PATH" != "$DESIRED")" >&2
                        exit 1
                    elif [[ "$REPOREF" != "*" ]]; then
                        pushd $REPO_DEST > /dev/null
                        # When we first clone we create a branch naming what we fetched
                        # that must match, or we are asking for two different references from the
                        # same repo, which is an error
                        if ! git rev-parse fetch_$REPOREF; then
                            echo "REPOREFS don't match - failed to get sha1 of fetch_$REPOREF" >&2
                            exit 1
                        fi
                        popd > /dev/null
                    fi
                else
                    sudo git clone -q $CACHE_PATH $REPO_DEST
                    pushd $REPO_DEST > /dev/null
                    if [[ "$REPOREF" == "*" ]]; then
                        sudo git fetch -q --prune --update-head-ok $CACHE_PATH \
                            +refs/heads/*:refs/heads/* +refs/tags/*:refs/tags/*
                        git_sha=$(git rev-parse HEAD)
                    else
                        sudo git fetch -q $CACHE_PATH $REPOREF:fetch_$REPOREF
                        sudo git reset --hard FETCH_HEAD
                        # Get the sha in use
                        git_sha=$(git rev-parse FETCH_HEAD)
                    fi
                    popd > /dev/null

                    # Write the sha being used into the source-repositories manifest
                    echo "$REPONAME git $REPOPATH $REPOLOCATION $git_sha" >> $GIT_MANIFEST
                fi
                ;;
            tar)
                # The top level directory of the tarball mightn't have a fixed name i.e.
                # it could contain version numbers etc... so we write it to a tmpdir
                # for inspection before transferring the contents into the target directory
                local tmpdir=$(mktemp --tmpdir=$TMP_MOUNT_PATH/tmp -d)
                if [ -n "$CACHE_PATH" ] ; then
                    echo "Caching $REPONAME tarball from $REPOLOCATION in $CACHE_PATH"
                    if [ ! -f "$CACHE_PATH" -o -z "$DIB_OFFLINE" ] ; then
                        $CACHE_URL $REPOLOCATION $CACHE_PATH
                    fi
                    tar -C $tmpdir -xzf $CACHE_PATH
                else
                    echo "Fetching $REPONAME tarball from $REPOLOCATION"
                    curl $REPOLOCATION | tar -C $tmpdir -xzf -
                fi

                sudo mkdir -p $REPO_DEST

                # A REPOREF of '.' will select the entire contents of the tarball,
                # while '*' will select only the contents of its subdirectories.
                sudo rsync -a --remove-source-files $tmpdir/$REPOREF/. $REPO_DEST

                rm -rf $tmpdir

                ;;
            file)
                sudo mkdir -p $REPO_SUB_DIRECTORY
                if [ -n "$CACHE_PATH" ] ; then
                    echo "Caching $REPONAME file from $REPOLOCATION in $CACHE_PATH"
                    if [ ! -f "$CACHE_PATH" -o -z "$DIB_OFFLINE" ] ; then
                        $CACHE_URL $REPOLOCATION $CACHE_PATH
                    fi
                    sudo cp $CACHE_PATH $REPO_DEST
                else
                    echo "Fetching $REPONAME file from $REPOLOCATION"
                    sudo curl $REPOLOCATION -o $REPO_DEST
                fi
                ;;
            *)
                echo "Unsupported repository type: $REPOTYPE"
                return 1
                ;;
            esac

            # Capture the in-instance repository path for later review / other
            # elements (like a pypi dependency cache).
            echo "$REPOPATH" | sudo tee -a $TMP_MOUNT_PATH/etc/dib-source-repositories > /dev/null

        else
            echo "Couldn't parse '$line' as a source repository"
            return 1
        fi
    done < $REPO_SOURCES
}

CACHE_BASE=$DIB_IMAGE_CACHE/source-repositories
OLD_CACHE_BASE=$DIB_IMAGE_CACHE/repository-sources
make_new_cache $OLD_CACHE_BASE $CACHE_BASE
mkdir -p $CACHE_BASE
# Use the IMAGE_NAME from the calling script, and make it unique with the temporary path
GIT_MANIFEST_NAME=dib-manifest-git-$(basename ${IMAGE_NAME})
GIT_MANIFEST_CACHE_NAME=${GIT_MANIFEST_NAME}_$(dirname ${TMP_MOUNT_PATH##*.})
GIT_MANIFEST=$CACHE_BASE/${GIT_MANIFEST_CACHE_NAME}
rm -f $GIT_MANIFEST

# Get source repositories for the target
for _SOURCEREPO in $(find $TMP_HOOKS_PATH -maxdepth 1 -name "source-repository-*" -not -name '*~'); do
    repo_flock=$CACHE_BASE/repositories_flock
    (
        echo "Getting $repo_flock: $(date) for $_SOURCEREPO"
        if ! flock -w 600 9 ; then
            echo "Did not get $repo_flock: $(date)"
            exit 1
        fi
        get_repos_for_element $_SOURCEREPO
    ) 9> $repo_flock
done

# Copy the manifest into the image if it exists (there may be no git repositories used)
if [ -e "$GIT_MANIFEST" ] ; then
    sudo mv $GIT_MANIFEST $TMP_MOUNT_PATH/${DIB_MANIFEST_IMAGE_DIR}/$GIT_MANIFEST_NAME
fi