#!/bin/sh
# git-flow -- A collection of Git extensions to provide high-level
# repository operations for Vincent Driessen's branching model.
#
# Original blog post presenting this model is found at:
#    http://nvie.com/git-model
#
# Feel free to contribute to this project at:
#    http://github.com/nvie/gitreflow
#
# Copyright 2010 Vincent Driessen. All rights reserved.
# 
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are met:
# 
#    1. Redistributions of source code must retain the above copyright notice,
#       this list of conditions and the following disclaimer.
# 
#    2. Redistributions in binary form must reproduce the above copyright
#       notice, this list of conditions and the following disclaimer in the
#       documentation and/or other materials provided with the distribution.
# 
# THIS SOFTWARE IS PROVIDED BY VINCENT DRIESSEN ``AS IS'' AND ANY EXPRESS OR
# IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
# MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
# EVENT SHALL VINCENT DRIESSEN OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
# INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
# BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
# OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
# NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
# EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
# 
# The views and conclusions contained in the software and documentation are
# those of the authors and should not be interpreted as representing official
# policies, either expressed or implied, of Vincent Driessen.
#

#
# Common functionality
#

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

escape() {
  echo "$1" | sed 's/\([\.\+\$\*]\)/\\\1/g'
}

# set logic
has() {
  local item=$1; shift
  echo " $@ " | grep -q " $(escape $item) "
}

# basic math
min() { [ "$1" -le "$2" ] && echo "$1" || echo "$2"; }
max() { [ "$1" -ge "$2" ] && echo "$1" || echo "$2"; }

# basic string matching
startswith() { [ "$1" != "${1#$2}" ]; }
endswith() { [ "$1" != "${1%$2}" ]; }

#
# Git specific common functionality
#

git_local_branches() { git branch --no-color | sed 's/^[* ] //'; }
git_remote_branches() { git branch -r --no-color | sed 's/^[* ] //'; }
git_all_branches() { ( git branch --no-color; git branch -r --no-color) | sed 's/^[* ] //'; }
git_all_tags() { git tag; }

git_current_branch() {
  git branch --no-color | grep '^\* ' | grep -v 'no branch' | sed 's/^* //g'
}

git_is_clean_working_tree() {
  if ! git diff --no-ext-diff --ignore-submodules --quiet --exit-code; then
    return 1
  elif ! git diff-index --cached --quiet --ignore-submodules HEAD --; then
    return 2
  else
    return 0
  fi
}

git_repo_is_headless() {
  ! git rev-parse --quiet --verify HEAD >/dev/null 2>&1
}

git_local_branch_exists() {
  has $1 $(git_local_branches)
}

git_remote_branch_exists() {
  has $1 $(git_remote_branches)
}

git_branch_exists() {
  has $1 $(git_all_branches)
}

git_tag_exists() {
  has $1 $(git_all_tags)
}

#
# git_compare_branches()
#
# 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
# 4    There is no merge base, i.e. the branches have no common ancestors
#
git_compare_branches() {
  local commit1=$(git rev-parse "$1")
  local commit2=$(git rev-parse "$2")
  if [ "$commit1" != "$commit2" ]; then
    local base=$(git merge-base "$commit1" "$commit2")
    if [ $? -ne 0 ]; then
      return 4
    elif [ "$commit1" = "$base" ]; then
      return 1
    elif [ "$commit2" = "$base" ]; then
      return 2
    else
      return 3
    fi
  else
    return 0
  fi
}

#
# git_is_branch_merged_into()
#
# Checks whether branch $1 is succesfully merged into $2
#
git_is_branch_merged_into() {
  local subject=$1
  local base=$2
  local all_merges="$(git branch --no-color --contains $subject | sed 's/^[* ] //')"
  has $base $all_merges
}

#
# gitreflow specific common functionality
#

# check if this repo has been inited for gitreflow
gitreflow_has_master_configured() {
  local master=$(git config --get gitreflow.branch.master)
  [ "$master" != "" ] && git_local_branch_exists "$master"
}

gitreflow_has_develop_configured() {
  local develop=$(git config --get gitreflow.branch.develop)
  [ "$develop" != "" ] && git_local_branch_exists "$develop"
}

gitreflow_has_prefixes_configured() {
  git config --get gitreflow.prefix.feature >/dev/null 2>&1     && \
  git config --get gitreflow.prefix.release >/dev/null 2>&1     && \
  git config --get gitreflow.prefix.hotfix >/dev/null 2>&1      && \
  git config --get gitreflow.prefix.support >/dev/null 2>&1     && \
  git config --get gitreflow.prefix.versiontag >/dev/null 2>&1
}

gitreflow_is_initialized() {
  gitreflow_has_master_configured                    && \
  gitreflow_has_develop_configured                   && \
  [ "$(git config --get gitreflow.branch.master)" !=    \
    "$(git config --get gitreflow.branch.develop)" ] && \
  gitreflow_has_prefixes_configured
}

# loading settings that can be overridden using git config
gitreflow_load_settings() {
  export DOT_GIT_DIR=$(git rev-parse --git-dir 2>/dev/null)
  export MASTER_BRANCH=$(git config --get gitreflow.branch.master)
  export DEVELOP_BRANCH=$(git config --get gitreflow.branch.develop)
  export ORIGIN=$(git config --get gitreflow.origin || echo origin)
}

#
# gitreflow_resolve_nameprefix
#
# Inputs:
# $1 = name prefix to resolve
# $2 = branch prefix to use
#
# Searches branch names from git_local_branches() to look for a unique
# branch name whose name starts with the given name prefix.
#
# There are multiple exit codes possible:
# 0: The unambiguous full name of the branch is written to stdout
#    (success)
# 1: No match is found.
# 2: Multiple matches found. These matches are written to stderr
#
gitreflow_resolve_nameprefix() {
  local name=$1
  local prefix=$2
  local matches
  local num_matches

  # first, check if there is a perfect match
  if git_local_branch_exists "$prefix$name"; then
    echo "$name"
    return 0
  fi

  matches=$(echo "$(git_local_branches)" | grep "^$(escape "$prefix$name")")
  num_matches=$(echo "$matches" | wc -l)
  if [ -z "$matches" ]; then
    # no prefix match, so take it literally
    warn "No branch matches prefix '$name'"
    return 1
  else
    if [ $num_matches -eq 1 ]; then
      echo "${matches#$prefix}"
      return 0
    else
      # multiple matches, cannot decide
      warn "Multiple branches match prefix '$name':"
      for match in $matches; do
        warn "- $match"
      done
      return 2
    fi
  fi
}

#
# Assertions for use in git-flow subcommands
#

require_git_repo() {
  if ! git rev-parse --git-dir >/dev/null 2>&1; then
    die "fatal: Not a git repository"
  fi
}

require_gitreflow_initialized() {
  if ! gitreflow_is_initialized; then
    die "fatal: Not a gitreflow-enabled repo yet. Please run \"git flow init\" first."
  fi
}

require_clean_working_tree() {
  git_is_clean_working_tree
  local result=$?
  if [ $result -eq 1 ]; then
    die "fatal: Working tree contains unstaged changes. Aborting."
  fi
  if [ $result -eq 2 ]; then
    die "fatal: Index contains uncommitted changes. Aborting."
  fi
}

require_local_branch() {
  if ! git_local_branch_exists $1; then
    die "fatal: Local branch '$1' does not exist and is required."
  fi
}

require_remote_branch() {
  if ! has $1 $(git_remote_branches); then
    die "Remote branch '$1' does not exist and is required."
  fi
}

require_branch() {
  if ! has $1 $(git_all_branches); then
    die "Branch '$1' does not exist and is required."
  fi
}

require_branch_absent() {
  if has $1 $(git_all_branches); then
    die "Branch '$1' already exists. Pick another name."
  fi
}

require_tag_absent() {
  for tag in $(git_all_tags); do
    if [ "$1" = "$tag" ]; then
      die "Tag '$1' already exists. Pick another name."
    fi
  done
}

require_branches_equal() {
  require_local_branch "$1"
  require_remote_branch "$2"
  git_compare_branches "$1" "$2"
  local status=$?
  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
      # Warn here, since there is no harm in being ahead
      warn "And local branch '$1' is ahead of '$2'."
    else
      die "Branches need merging first."
    fi
  fi
}