#!/bin/sh
 
-#set -x
+# This program is licensed under the GNU GPL version 2 or later.
+# (c) Richard "RichiH" Hartmann <richih.mailinglist@gmail.com>, 2011-2012
+# For details, see LICENSE. To submit patches, you have to agree to
+# license your code under the GNU GPL version 2 or later.
 
-SELF=$(basename $0)
 
-[ -z $XDG_CONFIG_HOME ] && XDG_CONFIG_HOME="$HOME/.config"
-for check_directory in $XDG_CONFIG_HOME $XDG_CONFIG_HOME/vcsh $XDG_CONFIG_HOME/vcsh/repo.d
-do
-       if [ ! -d $check_directory ]; then
-               if [ -e $check_directory ]; then
-                       echo "$SELF: error: $check_directory exists but is not a directory" >&2
-                       exit 2
-               else
-                       mkdir $check_directory || (echo "$SELF: error: could not create $check_directory" >&2; exit 2)
-               fi
-       fi
-done
+[ -n "$VCSH_DEBUG" ]                  && set -vx
+[ -z "$XDG_CONFIG_HOME" ]             && XDG_CONFIG_HOME="$HOME/.config"
+[ -r "$XDG_CONFIG_HOME/vcsh/config" ] && . "$XDG_CONFIG_HOME/vcsh/config"
+[ -n "$VCSH_DEBUG" ]                  && set -vx
+[ -z "$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'
 
-VCSH_BASE="$XDG_CONFIG_HOME/vcsh/repo.d"
+SELF=$(basename $0)
 
 help() {
        echo "usage: $SELF <args>
 
-   help           Display this help
+   clone <remote> \\
+         [<repo>]       Clone from an existing repository
+   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
+   list-tracked-by \\
+        <repo>          List files tracked by a repository
+   rename <repo> \\
+          <newname>     Rename repository
+   run <repo> \\
+       <command>        Use this repository
+   setup                Set up repository with recommended settings
+   which <substring>    Find substring in any tracked file name
+   write-gitignore \\
+   <repo>               Write .gitignore.d/<repo> via git ls-files
 
-   list           List all repos
+   <repo> <git command> Shortcut to run git commands directly
+   <repo>               Shortcut to enter repository" >&2
+}
 
-   use <repo>     Use this repository
-   run <repo>
-       <command>  Use this repository
+debug() {
+       [ -n "$VCSH_DEBUG" ] && echo "$SELF: debug: $@"
+}
 
-   init           Initialize a new repository
-   clone <remote>
-         [<repo>] Clone from an existing repository
+verbose() {
+       if [ -n "$VCSH_DEBUG" ] || [ -n "$VCSH_VERBOSE" ]; then echo "$SELF: verbose: $@"; fi
+}
 
-   exit           Exit vcsh mode" >&2
+fatal() {
+       echo "$SELF: fatal: $1" >&2
+       exit $2
 }
 
-use() {
-       REPO_NAME="$1"
-       GIT_DIR="$VCSH_BASE/$REPO_NAME.git"
+error() {
+       echo "$SELF: error: $1" >&2
+}
 
-       if [ ! -d "$GIT_DIR" ]; then
-               echo E: no repository found for "$REPO_NAME" >&2
-               return 2
+info() {
+       echo "$SELF: info: $1"
+}
+
+clone() {
+       init
+       git remote add origin "$GIT_REMOTE"
+       git config branch.master.remote origin
+       git config branch.master.merge  refs/heads/master
+       if [ $(git ls-remote origin master 2> /dev/null | wc -l ) -lt 1 ]; then
+               info "remote is empty, not merging anything"
+               exit
        fi
+       git fetch
+       for object in $(git ls-tree -r origin/master | awk '{print $4}'); do
+               [ -e "$object" ] &&
+                       error "'$object' exists." &&
+                       VCSH_CONFLICT=1;
+       done
+       [ "$VCSH_CONFLICT" = '1' ] &&
+               fatal "will stop after fetching and not try to merge!
+  Once this situation has been resolved, run 'vcsh run $VCSH_REPO_NAME git pull' to finish cloning.\n" 17
+       git merge origin/master
+}
 
-       export GIT_DIR
-       export GIT_WORK_TREE="$(git config --get core.worktree)"
-       export VCSH_DIRECTORY="$REPO_NAME"
+delete() {
+       cd "$VCSH_BASE" || fatal "could not enter '$VCSH_BASE'" 11
+       use
+       info "This operation WILL DETROY DATA!"
+       files=$(git ls-files)
+       echo "These files will be deleted:
+
+$files
+
+AGAIN, THIS WILL DELETE YOUR DATA!
+To continue, type 'Yes, do as I say'"
+       read answer
+       [ "x$answer" = 'xYes, do as I say' ] || exit 16
+       for file in $files; do
+               rm -f $file || info "could not delete '$file', continuing with deletion"
+       done
+       rmdir "$GIT_DIR" || error "could not delete '$GIT_DIR'"
+}
+
+enter() {
+       hook pre-enter
+       use
+       $SHELL
+       hook post-enter
+}
+
+git_dir_exists() {
+       [ -d "$GIT_DIR" ] || fatal "no repository found for '$VCSH_REPO_NAME'" 12
+}
+
+hook() {
+       for hook in $VCSH_HOOK_D/$1* $VCSH_HOOK_D/$VCSH_REPO_NAME.$1*; do
+               [ -x "$hook" ] || continue
+               info "executing '$hook'"
+               "$hook"
+       done
 }
 
 init() {
-       [[ -e $GIT_DIR ]] &&
-               echo "$SELF: fatal: $GIT_DIR exists" &&
-               return 21
-       export GIT_WORK_TREE="$HOME"
-       mkdir -p $GIT_WORK_TREE
-       cd $GIT_WORK_TREE ||
-               (echo "$SELF: fatal: could not enter $GIT_WORK_TREE" &&
-                exit 20) || exit 20
-       cd $GIT_WORK_TREE
+       [ ! -e "$GIT_DIR" ] || fatal "'$GIT_DIR' exists" 10
+       export GIT_WORK_TREE="$VCSH_BASE"
+       mkdir -p "$GIT_WORK_TREE" || fatal "could not create '$GIT_WORK_TREE'" 50
+       cd "$GIT_WORK_TREE" || fatal "could not enter '$GIT_WORK_TREE'" 11
        git init
-       git config core.worktree $GIT_WORK_TREE
+       setup
 }
 
-leave() {
-       unset GIT_DIR
-       unset GIT_WORK_TREE
-       unset VCSH_DIRECTORY
+list() {
+       for i in "$VCSH_REPO_D"/*.git; do
+               echo $(basename "$i" .git)
+       done
 }
 
-if [ "$1" = 'help' ] || [ $# -eq 0 ]; then
-       help
-       [ "$1" = 'help' ]
-       exit $?
+get_files() {
+       export GIT_DIR="$VCSH_REPO_D/$VCSH_REPO_NAME.git"
+       git ls-files
+}
 
-elif [ "$1" = 'list' ]; then
-       for i in $VCSH_BASE/*.git; do
-               echo $(basename $i .git)
-       done
-       exit 0
-
-elif [ "$1" = 'run' ]; then
-       use $2
-       shift 2
-       "$@"
-       leave
-       exit 0
-
-elif [ "$1" = 'use' ]; then
-       if [[ -o NO_IGNORE_EOF ]]; then
-               export VCSH_NO_IGNORE_EOF=1
-               setopt IGNORE_EOF
-               if [[ -n $ZSH_VERSION ]]; then
-                       vcsh_exit() {
-                               vcsh exit;
-                               zle reset-prompt;
-                       }
-               fi
-               zle -N vcsh_exit
-               bindkey '^d' 'vcsh_exit'
-       fi
-       use $2
-       buildPS1
-       exit 0
+list_tracked() {
+       for VCSH_REPO_NAME in $(list); do
+               get_files
+       done | sort -u
+}
 
-elif [ "$1" = 'clone' ]; then
-       GIT_REMOTE="$2"
-       REPO_NAME="$3"
-       [[ -z $REPO_NAME ]] && REPO_NAME=$(basename $GIT_REMOTE .git)
-       export REPO_NAME
-       export GIT_DIR="$VCSH_BASE/$REPO_NAME.git"
-       init
+list_tracked_by() {
+       use
+       git ls-files | sort -u
+}
 
-       git remote add origin $GIT_REMOTE
-       git config branch.master.remote origin
-       git config branch.master.merge  refs/heads/master
-       git fetch
-       for i in $(git ls-tree -r origin/master | awk '{print $4}'); do
-       [[ -e $i ]] &&
-               echo "$SELF: error: $i exists." &&
-               CONFLICT=1;
-       done
-       [[ -n $CONFLICT ]] &&
-               echo "$SELF: fatal: will stop after fetching and not try to merge!\n" &&
-               exit 3
-       git merge origin/master
-       vcsh use $REPO_NAME
+rename() {
+       git_dir_exists
+       [ -d "$GIT_DIR_NEW" ] && fatal "'$GIT_DIR_NEW' exists" 54
+       mv -f "$GIT_DIR" "$GIT_DIR_NEW" || fatal "Could not mv '$GIT_DIR' '$GIT_DIR_NEW'" 52
 
-elif [ "$1" = 'init' ]; then
-       export REPO_NAME="$2"
-       export GIT_DIR="$VCSH_BASE/$REPO_NAME.git"
-       init
-       vcsh use $REPO_NAME
+}
+
+run() {
+       hook pre-run
+       use
+       $VCSH_EXTERNAL_COMMAND
+       hook post-run
+}
+
+setup() {
+       hook pre-setup
+       use
+       git config core.worktree     "$GIT_WORK_TREE"
+       git config core.excludesfile ".gitignore.d/$VCSH_REPO_NAME"
+       git config vcsh.vcsh         'true'
+       [ -e "$VCSH_BASE/.gitignore.d/$VCSH_REPO_NAME" ] && git add -f "$VCSH_BASE/.gitignore.d/$VCSH_REPO_NAME"
+       hook post-setup
+}
+
+use() {
+       git_dir_exists
+       export GIT_WORK_TREE="$(git config --get core.worktree)"
+       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
+}
 
-elif [ "$1" = 'exit' ]; then
-       if [[ $VCSH_NO_IGNORE_EOF -gt 0 ]]; then
-               unset VCSH_NO_IGNORE_EOF
-               setopt NO_IGNORE_EOF
+write_gitignore() {
+       use
+       cd "$VCSH_BASE" || fatal "could not enter '$VCSH_BASE'" 11
+       gitignores=$(for file in $(git ls-files); do
+               while true; do
+                       echo $file; new="${file%/*}"
+                       [ "$file" = "$new" ] && break
+                       file="$new"
+               done;
+       done | sort -u)
+       tempfile=$(mktemp) || fatal "could not create tempfile" 51
+       echo '*' > "$tempfile" || fatal "could not write to '$tempfile'" 57
+       for gitignore in $gitignores; do
+               echo "$gitignore" | sed 's/^/!/' >> "$tempfile" || fatal "could not write to '$tempfile'" 57
+               if [ x$VCSH_GITIGNORE = x'recursive' ] && [ -d "$gitignore" ]; then
+                       { echo "$gitignore/*" | sed 's/^/!/' >> "$tempfile" || fatal "could not write to '$tempfile'" 57; }
+               fi
+       done
+       if diff -N "$tempfile" "$VCSH_BASE/.gitignore.d/$VCSH_REPO_NAME" > /dev/null; then
+               rm -f "$tempfile" || error "could not delete '$tempfile'"
+               exit
        fi
-       leave
-       buildPS1
-       exit 0
+       if [ -e "$VCSH_BASE/.gitignore.d/$VCSH_REPO_NAME" ]; then
+               info "'$VCSH_BASE/.gitignore.d/$VCSH_REPO_NAME' differs from new data, moving it to '$VCSH_BASE/.gitignore.d/$VCSH_REPO_NAME.bak'"
+               mv -f "$VCSH_BASE/.gitignore.d/$VCSH_REPO_NAME" "$VCSH_BASE/.gitignore.d/$VCSH_REPO_NAME.bak" ||
+                       fatal "could not move '$VCSH_BASE/.gitignore.d/$VCSH_REPO_NAME' to '$VCSH_BASE/.gitignore.d/$VCSH_REPO_NAME.bak'" 53
+       fi
+       mv -f "$tempfile" "$VCSH_BASE/.gitignore.d/$VCSH_REPO_NAME" ||
+               fatal "could not move '$tempfile' to '$VCSH_BASE/.gitignore.d/$VCSH_REPO_NAME'" 53
+}
+
+if [ ! "x$VCSH_GITIGNORE" = 'xexact' ] && [ ! "x$VCSH_GITIGNORE" = 'xrecursive' ]; then
+       fatal "'\$VCSH_GITIGNORE' must be either 'exact' or 'recursive'" 1
+fi
 
+if [ "$1" = 'clone' ]; then
+       [ -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" = '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
+       [ "$1" = 'run' -a -z "$3" ]    && fatal "$1: please specify a command" 1
+       export VCSH_COMMAND="$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" = 'write-gitignore' ]
+elif [ "$1" = 'list' ] ||
+     [ "$1" = 'list-tracked' ]; then
+       export VCSH_COMMAND="$1"
+elif [ -n "$2" ]; then
+       export VCSH_COMMAND='run'
+       export VCSH_REPO_NAME="$1"
+       export GIT_DIR="$VCSH_REPO_D/$VCSH_REPO_NAME.git"
+       [ -d $GIT_DIR ] || { help; exit 1; }
+       shift 1
+       export VCSH_EXTERNAL_COMMAND="git $*"
+elif [ -n "$1" ]; then
+       export VCSH_COMMAND='enter'
+       export VCSH_REPO_NAME="$1"
+       export GIT_DIR="$VCSH_REPO_D/$VCSH_REPO_NAME.git"
+       [ -d $GIT_DIR ] || { help; exit 1; }
 else
-       help
-       exit 3
+       # $1 is empty, or 'help'
+       help && exit
+fi
 
+# Did we receive a directory instead of a name?
+# Mangle the input to fit normal operation.
+if echo $VCSH_REPO_NAME | grep -q '/'; then
+       export GIT_DIR=$VCSH_REPO_NAME
+       export VCSH_REPO_NAME=$(basename "$VCSH_REPO_NAME" .git)
 fi
 
+
+for check_directory in "$VCSH_REPO_D" "$VCSH_BASE/.gitignore.d"
+do
+       if [ ! -d "$check_directory" ]; then
+               if [ -e "$check_directory" ]; then
+                       fatal "'$check_directory' exists but is not a directory" 13
+               else
+                       info "attempting to create '$check_directory'"
+                       mkdir -p "$check_directory" || fatal "could not create '$check_directory'" 50
+               fi
+       fi
+done
+
+verbose "$VCSH_COMMAND begin"
+export VCSH_COMMAND=$(echo $VCSH_COMMAND | sed 's/-/_/g')
+$VCSH_COMMAND
+verbose "$VCSH_COMMAND end, exiting"