# For details, see LICENSE. To submit patches, you have to agree to
 # license your code under the GNU GPL version 2 or later.
 
+# While the following is not legally binding, the author would like to
+# explain the choice of GPLv2+ over GPLv3+.
+# The author prefers GPLv3+ over GPLv2+ but feels it's better to maintain
+# full compability with git. In case git ever changes its licensing terms,
+# this software will most likely follow suit.
 
+SELF=$(basename $0)
+
+fatal() {
+       echo "$SELF: fatal: $1" >&2
+       exit $2
+}
+
+# We need to run getops as soon as possible so we catch -d and other
+# options that will modify our behaviour.
+# Commands are handled at the end of this script.
+while getopts  "c:dv" flag; do
+       if [ "$1" = '-d' ] || [ "$1" = '--debug' ]; then
+               set -vx
+               VCSH_DEBUG=1
+       elif [ "$1" = '-v' ];then
+               VCSH_VERBOSE=1
+       elif [ "$1" = '-c' ];then
+               VCSH_OPTION_CONFIG=$OPTARG
+       fi
+       shift 1
+done
+
+source_all() {
+       # Source file even if it's in $PWD and does not have any slashes in it
+       case "$1" in
+               */*) . "$1";;
+               *)   . "$PWD/$1";;
+       esac;
+}
+
+
+# Read configuration and set defaults if anything's not set
 [ -n "$VCSH_DEBUG" ]                  && set -vx
 [ -z "$XDG_CONFIG_HOME" ]             && XDG_CONFIG_HOME="$HOME/.config"
+
+# Read configuration files if there are any
+[ -r "/etc/vcsh/config" ]             && . "/etc/vcsh/config"
 [ -r "$XDG_CONFIG_HOME/vcsh/config" ] && . "$XDG_CONFIG_HOME/vcsh/config"
+if [ -n "$VCSH_OPTION_CONFIG" ]; then
+       # Source $VCSH_OPTION_CONFIG if it can be read and is in $PWD of $PATH
+       if [ -r "$VCSH_OPTION_CONFIG" ]; then
+               source_all "$VCSH_OPTION_CONFIG"
+       else
+               fatal "Can not read configuration file '$VCSH_OPTION_CONFIG'" 1
+       fi
+fi
 [ -n "$VCSH_DEBUG" ]                  && set -vx
+
+# Read defaults
 [ -z "$VCSH_REPO_D" ]                 && VCSH_REPO_D="$XDG_CONFIG_HOME/vcsh/repo.d"
 [ -z "$VCSH_HOOK_D" ]                 && VCSH_HOOK_D="$XDG_CONFIG_HOME/vcsh/hooks-enabled"
 [ -z "$VCSH_BASE" ]                   && VCSH_BASE="$HOME"
 [ -z "$VCSH_GITIGNORE" ]              && VCSH_GITIGNORE='exact'
 
-SELF=$(basename $0)
 
 help() {
-       echo "usage: $SELF <args>
+       echo "usage: $SELF <options> <command>
 
+   options:
+   -c <file>            Source file
+   -d                   Enable debug mode
+   -v                   Enable verbose mode
+
+   commands:
    clone <remote> \\
          [<repo>]       Clone from an existing repository
+   delete <repo>        Delete an existing repository
+   enter <repo>         Enter repository; spawn new instance of \$SHELL
    help                 Display this help text
-   delete               Delete an existing repository
-   enter                Enter repository; spawn new instance of \$SHELL
    init <repo>          Initialize a new repository
    list                 List all repositories
    list-tracked         List all files tracked by vcsh
           <newname>     Rename repository
    run <repo> \\
        <command>        Use this repository
-   setup                Set up repository with recommended settings
+   setup <repo>         Set up repository with recommended settings
+   which <substring>    Find substring in name of any tracked file
    write-gitignore \\
    <repo>               Write .gitignore.d/<repo> via git ls-files
 
        if [ -n "$VCSH_DEBUG" ] || [ -n "$VCSH_VERBOSE" ]; then echo "$SELF: verbose: $@"; fi
 }
 
-fatal() {
-       echo "$SELF: fatal: $1" >&2
-       exit $2
-}
-
 error() {
        echo "$SELF: error: $1" >&2
 }
 delete() {
        cd "$VCSH_BASE" || fatal "could not enter '$VCSH_BASE'" 11
        use
-       info "This operation WILL DETROY DATA!"
+       info "This operation WILL DESTROY DATA!"
        files=$(git ls-files)
        echo "These files will be deleted:
 
        for file in $files; do
                rm -f $file || info "could not delete '$file', continuing with deletion"
        done
-       rm -r "$GIT_DIR" || error "could not delete '$GIT_DIR'"
+       rm -rf "$GIT_DIR" || error "could not delete '$GIT_DIR'"
 }
 
 enter() {
 }
 
 list() {
-       for i in "$VCSH_REPO_D"/*.git; do
-               echo $(basename "$i" .git)
+       for repo in "$VCSH_REPO_D"/*.git; do
+               [ -d "$repo" ] && [ -r "$repo" ] && echo $(basename "$repo" .git)
        done
 }
 
 run() {
        hook pre-run
        use
-       $VCSH_EXTERNAL_COMMAND
+       "$@"
        hook post-run
 }
 
        export VCSH_DIRECTORY="$VCSH_REPO_NAME"
 }
 
+which() {
+       for VCSH_REPO_NAME in $(list); do
+               for VCSH_FILE in $(get_files); do
+                       echo $VCSH_FILE | grep -q "$VCSH_COMMAND_PARAMETER" && echo "$VCSH_REPO_NAME: $VCSH_FILE"
+               done
+       done | sort -u
+}
+
 write_gitignore() {
        use
        cd "$VCSH_BASE" || fatal "could not enter '$VCSH_BASE'" 11
 fi
 
 if [ "$1" = 'clone' ]; then
-       [ -z $2 ] && fatal "$1: please specify a remote" 1
+       [ -z "$2" ] && fatal "$1: please specify a remote" 1
        export VCSH_COMMAND="$1"
        GIT_REMOTE="$2"
        [ -n "$3" ] && VCSH_REPO_NAME="$3" || VCSH_REPO_NAME=$(basename "$GIT_REMOTE" .git)
        export VCSH_REPO_NAME
        export GIT_DIR="$VCSH_REPO_D/$VCSH_REPO_NAME.git"
-elif [ "$1" = 'delete' ]          ||
-     [ "$1" = 'enter' ]           ||
-     [ "$1" = 'init' ]            ||
-     [ "$1" = 'list-tracked-by' ] ||
-     [ "$1" = 'rename' ]          ||
-     [ "$1" = 'run' ]             ||
-     [ "$1" = 'setup' ]           ||
+elif [ "$1" = 'which' ]; then
+       [ -z "$2" ] && fatal "$1: please specify a filename" 1
+       [ -n "$3" ] && fatal "$1: too many parameters" 1
+       export VCSH_COMMAND="$1"
+       export VCSH_COMMAND_PARAMETER="$2"
+elif [ "$1" = 'delete' ]           ||
+     [ "$1" = 'enter' ]            ||
+     [ "$1" = 'init' ]             ||
+     [ "$1" = 'list-tracked-by' ]  ||
+     [ "$1" = 'rename' ]           ||
+     [ "$1" = 'run' ]              ||
+     [ "$1" = 'setup' ]            ||
      [ "$1" = 'write-gitignore' ]; then
        [ -z $2 ]                      && fatal "$1: please specify repository to work on" 1
        [ "$1" = 'rename' -a -z "$3" ] && fatal "$1: please specify a target name" 1
        export VCSH_REPO_NAME="$2"
        export GIT_DIR="$VCSH_REPO_D/$VCSH_REPO_NAME.git"
        [ "$VCSH_COMMAND" = 'rename' ]         && export GIT_DIR_NEW="$VCSH_REPO_D/$3.git"
-       [ "$VCSH_COMMAND" = 'run' ] && shift 2 && export VCSH_EXTERNAL_COMMAND="$*"
+       [ "$VCSH_COMMAND" = 'run' ] && shift 2
        [ "$VCSH_COMMAND" = 'write-gitignore' ]
 elif [ "$1" = 'list' ] ||
      [ "$1" = 'list-tracked' ]; then
        export GIT_DIR="$VCSH_REPO_D/$VCSH_REPO_NAME.git"
        [ -d $GIT_DIR ] || { help; exit 1; }
        shift 1
-       export VCSH_EXTERNAL_COMMAND="git $*"
+       set -- "git" "$@"
 elif [ -n "$1" ]; then
        export VCSH_COMMAND='enter'
        export VCSH_REPO_NAME="$1"
 
 verbose "$VCSH_COMMAND begin"
 export VCSH_COMMAND=$(echo $VCSH_COMMAND | sed 's/-/_/g')
-$VCSH_COMMAND
+hook pre-command
+$VCSH_COMMAND "$@"
+hook post-command
 verbose "$VCSH_COMMAND end, exiting"