#!/bin/bash
# I'm writing this in BASH because I hate myself, apparently.

list_branches() {
    git for-each-ref refs/heads --format="%(refname:short)"
}

list_remote_branches() {
    git for-each-ref refs/heads --format="%(refname:short)"
}

case "$1" in
"")
echo 'TODO: Display help, or git status if inside a repo'
;;

stage)
if [ -z "$2" ]; then
    echo Staging all modified files
    git add -u :/
else
    echo Staging "${@:2}"
    git add "${@:2}"
fi
;;

unstage)
echo Unstaging
if [ -z "$2" ]; then
    echo The stage has been reset.
    git reset HEAD
else
    git reset HEAD "${@:2}"
fi
;;

reset)
echo Resetting
if [ -z "$2" ]; then
    echo The working directory has been reset.
    git checkout -f HEAD
else
    git checkout "${@:2}"
fi
;;

commit)
echo Committing
if [ -z "$2" ]; then
    read -p 'Message: ' msg
    git commit -m "$msg"
else
    git commit -m "$2"
fi
;;

branch)
echo 'Switching to branch'
if [ -z "$2" ]; then
    echo '! Specify branch name'
else
    git stash # Save branch index state
    if git rev-parse --verify --quiet "$2" > /dev/null; then
        git checkout "$2"
    else
        git checkout -b "$2"
    fi
    git stash pop # Restore branch index state
fi
;;

rmbranch)
echo 'Delete branch'
if [ -z "$2" ]; then
    echo '! Specify branch name'
else
    git branch -d "$2"
fi
;;

fetch)
echo Updating
if [ -z "$2" ]; then
    git fetch --all
    branches="$(list_branches)"
else
    branches = "${@:2}"
    git fetch "$branches"
fi
# Fast-forward local branches. I owe a lot to http://stackoverflow.com/a/24451300/2168416
current_branch=$(git rev-parse --abbrev-ref HEAD)
for local_branch in $branches; do
    remote=$(git config --get branch.$local_branch.remote)
    remote_branch=$(git config --get branch.$local_branch.merge | sed 's:refs/heads/::')
    # Git throws an error if we try the fetch command on the current branch. Sheesh
    if [ "$current_branch" = "$local_branch" ]; then
        git merge --ff-only $remote/$remote_branch
    else
        git fetch $remote $remote_branch:$local_branch
    fi
done
;;

ignore)

;;

status)
# TODO: figure out how to git config --global color.status always automatically.
git status \
| grep -v '# On branch' \
| grep -v '#   (use "git push" to publish your local commits)' \
| grep -v '#   (use "git reset HEAD <file>..." to unstage)' \
| grep -v '#   (use "git add <file>..." to update what will be committed)' \
| grep -v '#   (use "git checkout -- <file>..." to discard changes in working directory)' \
| grep -v '#   (use "git add <file>..." to include in what will be committed)' \
| grep -v 'nothing added to commit but untracked files present (use "git add" to track)'
;;

diff)
if [ -z "$2" ]; then
    echo 'Compare working tree with HEAD'
    git diff HEAD
else
    if [ -z "$3" ]; then
        if [ "$2" = 'STAGE' ]; then
            echo 'Compare working tree with stage'
            git diff
        else
            echo "Compare working tree with $2"
            git diff "$2"
        fi
    else
        if [ "$2" = 'STAGE' ]; then
            echo "Compare stage with $3"
            git diff --cached "$3"
        else
            echo "Compare $2 with $3"
            git diff "$2" "$3"
        fi
    fi
fi
;;

review)
echo 'Compare stage with HEAD'
git diff --cached HEAD
;;

push)
echo 'Pushing'
# Check to see if upstream is set.
if git rev-parse --abbrev-ref @{upstream} >/dev/null ; then
    git push
else
    # Get local branch name
    local_branch=$(git rev-parse --abbrev-ref HEAD)
    # Check for multiple remotes
    remote_count=$(git remote show | wc -l)
    remotes=$(git remote show | tr '\n' ' ' | sed 's/\s*$//g')
    if [ "$remote_count" = "1" ]; then
        # If only one remote
        remote="$remotes"
    else
        read -p "Which remote to push? (${remotes}): " remote
    fi
    read -p "Choose name for branch on '${remote}' [${local_branch}]: " remote_branch
    if [ "$remote_branch" = "" ]; then
        remote_branch="$local_branch"
    fi
    echo "I will run git push --set-upstream ${remote} ${remote_branch}"
    git push --set-upstream ${remote} ${remote_branch}
fi
;;

esac