#!/bin/sh
#
# gitflow -- A collection of Git wrapper scripts to provide high-level
# repository operations for Vincent Driessen's branching model:
# 
# Original blog post presenting this model is found at:
#    http://nvie.com/archives/323
# 
# Feel free to contribute to this project at:
#    http://github.com/nvie/gitflow
#
# Copyright (c) 2010 by Vincent Driessen
#

# Get the git dir
GIT_DIR=$(git rev-parse --git-dir)

# Get all available branches
LOCAL_BRANCHES=$(cd "$GIT_DIR/refs/heads"; find * -type f)
REMOTE_BRANCHES=$(cd "$GIT_DIR/refs/remotes"; find * -type f)
ALL_BRANCHES="$LOCAL_BRANCHES\n$REMOTE_BRANCHES"

warn() { echo "$@" >&2; }
die() { warn "$@"; exit 1; }

gitflow_check_clean_working_tree() {
	if [ "$(git status 2> /dev/null | tail -n1)" != "nothing to commit (working directory clean)" ]; then
		die "Working directory is dirty. Only use gitflow in clean working directories for your own safety."
	fi
}

gitflow_require_local_branch() {
	echo "$LOCAL_BRANCHES" | grep "^$1\$" 2>/dev/null >/dev/null
	if [ $? -ne 0 ]; then
		die "Local branch '$1' does not exist and is required."
	fi
}

gitflow_require_remote_branch() {
	echo "$REMOTE_BRANCHES" | grep "^$1\$" 2>/dev/null >/dev/null
	if [ $? -ne 0 ]; then
		die "Remote branch '$1' does not exist and is required."
	fi
}

gitflow_require_branch() {
	echo "$ALL_BRANCHES" | grep "^$1\$" 2>/dev/null >/dev/null
	if [ $? -ne 0 ]; then
		die "Branch '$1' does not exist and is required."
	fi
}

#
# gitflow_test_branches_equal()
# 
# Tests whether branches and their "origin" counterparts have diverged and need
# merging first. It returns error codes to provide more detail, like so:
# 
# 0		Branch heads point to the same commit
# 1		First given branch needs fast-forwarding
# 2		Second given branch needs fast-forwarding
# 3		Branch needs a real merge
#
gitflow_test_branches_equal() {
	commit1=$(git rev-parse "$1")
	commit2=$(git rev-parse "$2")
	if [ "$commit1" != "$commit2" ]; then
		base=$(git merge-base "$commit1" "$commit2")
		short_base=$(git rev-parse --short "$base")

		if [ "$commit1" = "$base" ]; then
			return 1
		elif [ "$commit2" = "$base" ]; then
			return 2
		else
			return 3
		fi
	else
		return 0
	fi
}

gitflow_require_branches_equal() {
	gitflow_require_local_branch "$1"
	gitflow_require_remote_branch "$2"
	gitflow_test_branches_equal "$1" "$2"
	status=$?
	if [ $status -gt 0 ]; then
		warn "Branches '$1' and '$2' have diverged."

		if [ $status -eq 1 ]; then
			die "And branch '$1' may be fast-forwarded."
		elif [ $status -eq 2 ]; then
			die "And local branch '$1' is ahead of '$2'."
		else
			die "Branches need merging first."
		fi
	fi
}