Cleanup argument parsing and delegation

[code/vcsh.git] / vcsh

#!/bin/sh

[ -n "$VCSH_DEBUG" ]      && set -x
[ -z "$XDG_CONFIG_HOME" ] && XDG_CONFIG_HOME="$HOME/.config"
[ -z "$VCSH_BASE" ]       && VCSH_BASE="$XDG_CONFIG_HOME/vcsh/repo.d"

SELF=$(basename $0)

help() {
        echo "usage: $SELF <args>

   clone <remote> \\
         [<repo>]       Clone from an existing repository
   help                 Display this help text
   delete               Delete an existing repository
   enter                Enter repository; spawn new $SHELL
   init <repo>          Initialize a new repository
   list                 List all repositories
   run <repo> \\
       <command>        Use this repository

   seed-gitignore \\
   <repo>               Seed .gitignore.d/<repo> from git ls-files
   setup                Set up repository with recommended settings

   <repo> <git command> Special command that allows you to run git commands
                        directly without having to type so much ;)" >&2
}

debug() {
        [ -n "$VCSH_DEBUG" ] && echo "$SELF: debug: $@"
}

verbose() {
        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
}

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
        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
}

delete () {
        old_dir="$PWD"
        cd "$HOME"
        use || exit $?
        info "This operation WILL DETROY DATA!"
        files=$(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
        rm -rf "$GIT_DIR" || info "could not delete '$GIT_DIR'"
        cd "$old_dir"
}

enter () {
        use || exit $?
        $SHELL
}

init() {
        [ ! -e "$GIT_DIR" ] || fatal "'$GIT_DIR' exists" 10
        export GIT_WORK_TREE="$HOME"
        mkdir -p "$GIT_WORK_TREE"
        cd "$GIT_WORK_TREE" || fatal "could not enter '$GIT_WORK_TREE'" 11
        cd "$GIT_WORK_TREE"
        git init
        setup
}

list () {
        for i in "$VCSH_BASE"/*.git; do
                echo $(basename "$i" .git)
        done
}

run () {
        use || exit $?
        $VCSH_EXTERNAL_COMMAND
}

seed_gitignore () {
        use || exit $?
        # Switching directory as this has to be executed from $HOME to be of any use.
        # Going back into old directory at the end in case `vcsh use` is reactivated.
        old_dir="$PWD"
        cd "$HOME"
        gitignores=$(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"
        for gitignore in $gitignores; do
                echo "$gitignore" | sed 's/^/!/' >> "$tempfile"
                [ -d "$gitignore" ] && echo "$gitignore/*" | sed 's/^/!/'>> "$tempfile"
        done
        diff -N "$tempfile" "$HOME/.gitignore.d/$VCSH_REPO_NAME" > /dev/null &&
                rm -f "$tempfile" &&
                exit
        if [ -e "$HOME/.gitignore.d/$VCSH_REPO_NAME" ]; then
                info "'$HOME/.gitignore.d/$VCSH_REPO_NAME' differs from new data, moving it to '$HOME/.gitignore.d/$VCSH_REPO_NAME.bak'"
                mv -f "$HOME/.gitignore.d/$VCSH_REPO_NAME" "$HOME/.gitignore.d/$VCSH_REPO_NAME.bak" ||
                        fatal "could not move '$HOME/.gitignore.d/$VCSH_REPO_NAME' to '$HOME/.gitignore.d/$VCSH_REPO_NAME.bak'" 53
        fi
        mv -f "$tempfile" "$HOME/.gitignore.d/$VCSH_REPO_NAME" ||
                fatal "could not move '$tempfile' to '$HOME/.gitignore.d/$VCSH_REPO_NAME'" 53
        cd "$old_dir"
}

setup() {
        use
        git config core.worktree     "$GIT_WORK_TREE"
        git config core.excludesfile ".gitignore.d/$VCSH_REPO_NAME"
        git config vcsh.vcsh         'true'
        touch   "$HOME/.gitignore.d/$VCSH_REPO_NAME"
        git add "$HOME/.gitignore.d/$VCSH_REPO_NAME"
}

use() {
        if [ ! -d "$GIT_DIR" ]; then
                error "no repository found for '$VCSH_REPO_NAME'"
                return 12
        fi
        export GIT_WORK_TREE="$(git config --get core.worktree)"
        export VCSH_DIRECTORY="$VCSH_REPO_NAME"
}

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_BASE/$VCSH_REPO_NAME.git"
elif [ "$1" = 'delete' ] ||
     [ "$1" = 'enter' ] ||
     [ "$1" = 'init' ] ||
     [ "$1" = 'run' ] ||
     [ "$1" = 'seed-gitignore' ] ||
     [ "$1" = 'setup' ]; then
        [ -z $2 ] && fatal "$1: please specify repository to work on" 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_BASE/$VCSH_REPO_NAME.git"
        [ "$1" = 'run' ] && shift 2 && export VCSH_EXTERNAL_COMMAND="$@"
        [ "$1" = 'seed-gitignore' ] && export VCSH_COMMAND=seed_gitignore
elif [ "$1" = 'list' ]; then
        export VCSH_COMMAND="$1"
elif [ -n "$1" ]; then
        export VCSH_COMMAND=run
        export VCSH_REPO_NAME="$1"
        export GIT_DIR="$VCSH_BASE/$VCSH_REPO_NAME.git"
        [ -d $GIT_DIR ] || { help; exit 1; }
        shift 1
        export VCSH_EXTERNAL_COMMAND="git $*"
else
        # $1 is empty, or 'help'
        help && exit
fi

for check_directory in "$VCSH_BASE" "$HOME/.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"
$VCSH_COMMAND
verbose "$VCSH_COMMAND end, exiting"