# bash/zsh git prompt support
#
# Copyright (C) 2006,2007 Shawn O. Pearce <spearce@spearce.org>
# Distributed under the GNU General Public License, version 2.0.
#
# This script allows you to see repository status in your prompt.
#
# To enable:
#
#    1) Copy this file to somewhere (e.g. ~/.git-prompt.sh).
#    2) Add the following line to your .bashrc/.zshrc:
#        source ~/.git-prompt.sh
#    3a) Change your PS1 to call __git_ps1 as
#        command-substitution:
#        Bash: PS1='[\u@\h \W$(__git_ps1 " (%s)")]\$ '
#        ZSH:  setopt PROMPT_SUBST ; PS1='[%n@%m %c$(__git_ps1 " (%s)")]\$ '
#        the optional argument will be used as format string.
#    3b) Alternatively, for a slightly faster prompt, __git_ps1 can
#        be used for PROMPT_COMMAND in Bash or for precmd() in Zsh
#        with two parameters, <pre> and <post>, which are strings
#        you would put in $PS1 before and after the status string
#        generated by the git-prompt machinery.  e.g.
#        Bash: PROMPT_COMMAND='__git_ps1 "\u@\h:\w" "\\\$ "'
#          will show username, at-sign, host, colon, cwd, then
#          various status string, followed by dollar and SP, as
#          your prompt.
#        ZSH:  precmd () { __git_ps1 "%n" ":%~$ " "|%s" }
#          will show username, pipe, then various status string,
#          followed by colon, cwd, dollar and SP, as your prompt.
#        Optionally, you can supply a third argument with a printf
#        format string to finetune the output of the branch status
#
# The repository status will be displayed only if you are currently in a
# git repository. The %s token is the placeholder for the shown status.
#
# The prompt status always includes the current branch name.
#
# In addition, if you set GIT_PS1_SHOWDIRTYSTATE to a nonempty value,
# unstaged (*) and staged (+) changes will be shown next to the branch
# name.  You can configure this per-repository with the
# bash.showDirtyState variable, which defaults to true once
# GIT_PS1_SHOWDIRTYSTATE is enabled.
#
# You can also see if currently something is stashed, by setting
# GIT_PS1_SHOWSTASHSTATE to a nonempty value. If something is stashed,
# then a '$' will be shown next to the branch name.
#
# If you would like to see if there're untracked files, then you can set
# GIT_PS1_SHOWUNTRACKEDFILES to a nonempty value. If there're untracked
# files, then a '%' will be shown next to the branch name.  You can
# configure this per-repository with the bash.showUntrackedFiles
# variable, which defaults to true once GIT_PS1_SHOWUNTRACKEDFILES is
# enabled.
#
# If you would like to see the difference between HEAD and its upstream,
# set GIT_PS1_SHOWUPSTREAM="auto".  A "<" indicates you are behind, ">"
# indicates you are ahead, "<>" indicates you have diverged and "="
# indicates that there is no difference. You can further control
# behaviour by setting GIT_PS1_SHOWUPSTREAM to a space-separated list
# of values:
#
#     verbose       show number of commits ahead/behind (+/-) upstream
#     name          if verbose, then also show the upstream abbrev name
#     legacy        don't use the '--count' option available in recent
#                   versions of git-rev-list
#     git           always compare HEAD to @{upstream}
#     svn           always compare HEAD to your SVN upstream
#
# By default, __git_ps1 will compare HEAD to your SVN upstream if it can
# find one, or @{upstream} otherwise.  Once you have set
# GIT_PS1_SHOWUPSTREAM, you can override it on a per-repository basis by
# setting the bash.showUpstream config variable.
#
# If you would like to see more information about the identity of
# commits checked out as a detached HEAD, set GIT_PS1_DESCRIBE_STYLE
# to one of these values:
#
#     contains      relative to newer annotated tag (v1.6.3.2~35)
#     branch        relative to newer tag or branch (master~4)
#     describe      relative to older annotated tag (v1.6.3.1-13-gdd42c2f)
#     default       exactly matching tag
#
# If you would like a colored hint about the current dirty state, set
# GIT_PS1_SHOWCOLORHINTS to a nonempty value. The colors are based on
# the colored output of "git status -sb" and are available only when
# using __git_ps1 for PROMPT_COMMAND or precmd.

# check whether printf supports -v
__git_printf_supports_v=
printf -v __git_printf_supports_v -- '%s' yes >/dev/null 2>&1

# stores the divergence from upstream in $p
# used by GIT_PS1_SHOWUPSTREAM
__git_ps1_show_upstream ()
{
    local key value
    local svn_remote svn_url_pattern count n
    local upstream=git legacy="" verbose="" name=""

    svn_remote=()
    # get some config options from git-config
    local output="$(git config -z --get-regexp '^(svn-remote\..*\.url|bash\.showupstream)$' 2>/dev/null | tr '\0\n' '\n ')"
    while read -r key value; do
        case "$key" in
        bash.showupstream)
            GIT_PS1_SHOWUPSTREAM="$value"
            if [[ -z "${GIT_PS1_SHOWUPSTREAM}" ]]; then
                p=""
                return
            fi
            ;;
        svn-remote.*.url)
            svn_remote[$((${#svn_remote[@]} + 1))]="$value"
            svn_url_pattern="$svn_url_pattern\\|$value"
            upstream=svn+git # default upstream is SVN if available, else git
            ;;
        esac
    done <<< "$output"

    # parse configuration values
    for option in ${GIT_PS1_SHOWUPSTREAM}; do
        case "$option" in
        git|svn) upstream="$option" ;;
        verbose) verbose=1 ;;
        legacy)  legacy=1  ;;
        name)    name=1 ;;
        esac
    done

    # Find our upstream
    case "$upstream" in
    git)    upstream="@{upstream}" ;;
    svn*)
        # get the upstream from the "git-svn-id: ..." in a commit message
        # (git-svn uses essentially the same procedure internally)
        local -a svn_upstream
        svn_upstream=($(git log --first-parent -1 \
                    --grep="^git-svn-id: \(${svn_url_pattern#??}\)" 2>/dev/null))
        if [[ 0 -ne ${#svn_upstream[@]} ]]; then
            svn_upstream=${svn_upstream[${#svn_upstream[@]} - 2]}
            svn_upstream=${svn_upstream%@*}
            local n_stop="${#svn_remote[@]}"
            for ((n=1; n <= n_stop; n++)); do
                svn_upstream=${svn_upstream#${svn_remote[$n]}}
            done

            if [[ -z "$svn_upstream" ]]; then
                # default branch name for checkouts with no layout:
                upstream=${GIT_SVN_ID:-git-svn}
            else
                upstream=${svn_upstream#/}
            fi
        elif [[ "svn+git" = "$upstream" ]]; then
            upstream="@{upstream}"
        fi
        ;;
    esac

    # Find how many commits we are ahead/behind our upstream
    if [[ -z "$legacy" ]]; then
        count="$(git rev-list --count --left-right \
                "$upstream"...HEAD 2>/dev/null)"
    else
        # produce equivalent output to --count for older versions of git
        local commits
        if commits="$(git rev-list --left-right "$upstream"...HEAD 2>/dev/null)"
        then
            local commit behind=0 ahead=0
            for commit in $commits
            do
                case "$commit" in
                "<"*) ((behind++)) ;;
                *)    ((ahead++))  ;;
                esac
            done
            count="$behind      $ahead"
        else
            count=""
        fi
    fi

    # calculate the result
    if [[ -z "$verbose" ]]; then
        case "$count" in
        "") # no upstream
            p="" ;;
        "0      0") # equal to upstream
            p="=" ;;
        "0      "*) # ahead of upstream
            p=">" ;;
        *"      0") # behind upstream
            p="<" ;;
        *)          # diverged from upstream
            p="<>" ;;
        esac
    else
        case "$count" in
        "") # no upstream
            p="" ;;
        "0      0") # equal to upstream
            p=" u=" ;;
        "0      "*) # ahead of upstream
            p=" u+${count#0     }" ;;
        *"      0") # behind upstream
            p=" u-${count%      0}" ;;
        *)          # diverged from upstream
            p=" u+${count#*     }-${count%      *}" ;;
        esac
        if [[ -n "$count" && -n "$name" ]]; then
            __git_ps1_upstream_name=$(git rev-parse \
                --abbrev-ref "$upstream" 2>/dev/null)
            if [ $pcmode = yes ] && [ $ps1_expanded = yes ]; then
                p="$p \${__git_ps1_upstream_name}"
            else
                p="$p ${__git_ps1_upstream_name}"
                # not needed anymore; keep user's
                # environment clean
                unset __git_ps1_upstream_name
            fi
        fi
    fi

}

# Helper function that is meant to be called from __git_ps1.  It
# injects color codes into the appropriate gitstring variables used
# to build a gitstring.
__git_ps1_colorize_gitstring ()
{
    if [[ -n ${ZSH_VERSION-} ]]; then
        local c_red='%F{red}'
        local c_green='%F{green}'
        local c_lblue='%F{blue}'
        local c_clear='%f'
    else
        # Using \[ and \] around colors is necessary to prevent
        # issues with command line editing/browsing/completion!
        local c_red='\[\e[31m\]'
        local c_green='\[\e[32m\]'
        local c_lblue='\[\e[1;34m\]'
        local c_clear='\[\e[0m\]'
    fi
    local bad_color=$c_red
    local ok_color=$c_green
    local flags_color="$c_lblue"

    local branch_color=""
    if [ $detached = no ]; then
        branch_color="$ok_color"
    else
        branch_color="$bad_color"
    fi
    c="$branch_color$c"

    z="$c_clear$z"
    if [ "$w" = "*" ]; then
        w="$bad_color$w"
    fi
    if [ -n "$i" ]; then
        i="$ok_color$i"
    fi
    if [ -n "$s" ]; then
        s="$flags_color$s"
    fi
    if [ -n "$u" ]; then
        u="$bad_color$u"
    fi
    r="$c_clear$r"
}

__git_eread ()
{
    f="$1"
    shift
    test -r "$f" && read "$@" <"$f"
}

# __git_ps1 accepts 0 or 1 arguments (i.e., format string)
# when called from PS1 using command substitution
# in this mode it prints text to add to bash PS1 prompt (includes branch name)
#
# __git_ps1 requires 2 or 3 arguments when called from PROMPT_COMMAND (pc)
# in that case it _sets_ PS1. The arguments are parts of a PS1 string.
# when two arguments are given, the first is prepended and the second appended
# to the state string when assigned to PS1.
# The optional third parameter will be used as printf format string to further
# customize the output of the git-status string.
# In this mode you can request colored hints using GIT_PS1_SHOWCOLORHINTS=true
__git_ps1 ()
{
    local pcmode=no
    local detached=no
    local ps1pc_start='\u@\h:\w '
    local ps1pc_end='\$ '
    local printf_format=' (%s)'

    case "$#" in
        2|3)    pcmode=yes
            ps1pc_start="$1"
            ps1pc_end="$2"
            printf_format="${3:-$printf_format}"
        ;;
        0|1)    printf_format="${1:-$printf_format}"
        ;;
        *)      return
        ;;
    esac

    # ps1_expanded:  This variable is set to 'yes' if the shell
    # subjects the value of PS1 to parameter expansion:
    #
    #   * bash does unless the promptvars option is disabled
    #   * zsh does not unless the PROMPT_SUBST option is set
    #   * POSIX shells always do
    #
    # If the shell would expand the contents of PS1 when drawing
    # the prompt, a raw ref name must not be included in PS1.
    # This protects the user from arbitrary code execution via
    # specially crafted ref names.  For example, a ref named
    # 'refs/heads/$(IFS=_;cmd=sudo_rm_-rf_/;$cmd)' might cause the
    # shell to execute 'sudo rm -rf /' when the prompt is drawn.
    #
    # Instead, the ref name should be placed in a separate global
    # variable (in the __git_ps1_* namespace to avoid colliding
    # with the user's environment) and that variable should be
    # referenced from PS1.  For example:
    #
    #     __git_ps1_foo=$(do_something_to_get_ref_name)
    #     PS1="...stuff...\${__git_ps1_foo}...stuff..."
    #
    # If the shell does not expand the contents of PS1, the raw
    # ref name must be included in PS1.
    #
    # The value of this variable is only relevant when in pcmode.
    #
    # Assume that the shell follows the POSIX specification and
    # expands PS1 unless determined otherwise.  (This is more
    # likely to be correct if the user has a non-bash, non-zsh
    # shell and safer than the alternative if the assumption is
    # incorrect.)
    #
    local ps1_expanded=yes
    [ -z "$ZSH_VERSION" ] || [[ -o PROMPT_SUBST ]] || ps1_expanded=no
    [ -z "$BASH_VERSION" ] || shopt -q promptvars || ps1_expanded=no

    local repo_info rev_parse_exit_code
    repo_info="$(git rev-parse --git-dir --is-inside-git-dir \
        --is-bare-repository --is-inside-work-tree \
        --short HEAD 2>/dev/null)"
    rev_parse_exit_code="$?"

    if [ -z "$repo_info" ]; then
        if [ $pcmode = yes ]; then
            #In PC mode PS1 always needs to be set
            PS1="$ps1pc_start$ps1pc_end"
        fi
        return
    fi

    local short_sha
    if [ "$rev_parse_exit_code" = "0" ]; then
        short_sha="${repo_info##*$'\n'}"
        repo_info="${repo_info%$'\n'*}"
    fi
    local inside_worktree="${repo_info##*$'\n'}"
    repo_info="${repo_info%$'\n'*}"
    local bare_repo="${repo_info##*$'\n'}"
    repo_info="${repo_info%$'\n'*}"
    local inside_gitdir="${repo_info##*$'\n'}"
    local g="${repo_info%$'\n'*}"

    local r=""
    local b=""
    local step=""
    local total=""
    if [ -d "$g/rebase-merge" ]; then
        __git_eread "$g/rebase-merge/head-name" b
        __git_eread "$g/rebase-merge/msgnum" step
        __git_eread "$g/rebase-merge/end" total
        if [ -f "$g/rebase-merge/interactive" ]; then
            r="|REBASE-i"
        else
            r="|REBASE-m"
        fi
    else
        if [ -d "$g/rebase-apply" ]; then
            __git_eread "$g/rebase-apply/next" step
            __git_eread "$g/rebase-apply/last" total
            if [ -f "$g/rebase-apply/rebasing" ]; then
                __git_eread "$g/rebase-apply/head-name" b
                r="|REBASE"
            elif [ -f "$g/rebase-apply/applying" ]; then
                r="|AM"
            else
                r="|AM/REBASE"
            fi
        elif [ -f "$g/MERGE_HEAD" ]; then
            r="|MERGING"
        elif [ -f "$g/CHERRY_PICK_HEAD" ]; then
            r="|CHERRY-PICKING"
        elif [ -f "$g/REVERT_HEAD" ]; then
            r="|REVERTING"
        elif [ -f "$g/BISECT_LOG" ]; then
            r="|BISECTING"
        fi

        if [ -n "$b" ]; then
            :
        elif [ -h "$g/HEAD" ]; then
            # symlink symbolic ref
            b="$(git symbolic-ref HEAD 2>/dev/null)"
        else
            local head=""
            if ! __git_eread "$g/HEAD" head; then
                if [ $pcmode = yes ]; then
                    PS1="$ps1pc_start$ps1pc_end"
                fi
                return
            fi
            # is it a symbolic ref?
            b="${head#ref: }"
            if [ "$head" = "$b" ]; then
                detached=yes
                b="$(
                case "${GIT_PS1_DESCRIBE_STYLE-}" in
                (contains)
                    git describe --contains HEAD ;;
                (branch)
                    git describe --contains --all HEAD ;;
                (describe)
                    git describe HEAD ;;
                (* | default)
                    git describe --tags --exact-match HEAD ;;
                esac 2>/dev/null)" ||

                b="$short_sha..."
                b="($b)"
            fi
        fi
    fi

    if [ -n "$step" ] && [ -n "$total" ]; then
        r="$r $step/$total"
    fi

    local w=""
    local i=""
    local s=""
    local u=""
    local c=""
    local p=""

    if [ "true" = "$inside_gitdir" ]; then
        if [ "true" = "$bare_repo" ]; then
            c="BARE:"
        else
            b="GIT_DIR!"
        fi
    elif [ "true" = "$inside_worktree" ]; then
        if [ -n "${GIT_PS1_SHOWDIRTYSTATE-}" ] &&
           [ "$(git config --bool bash.showDirtyState)" != "false" ]
        then
            git diff --no-ext-diff --quiet --exit-code || w="*"
            if [ -n "$short_sha" ]; then
                git diff-index --cached --quiet HEAD -- || i="+"
            else
                i="#"
            fi
        fi
        if [ -n "${GIT_PS1_SHOWSTASHSTATE-}" ] &&
           git rev-parse --verify --quiet refs/stash >/dev/null
        then
            s="$"
        fi

        if [ -n "${GIT_PS1_SHOWUNTRACKEDFILES-}" ] &&
           [ "$(git config --bool bash.showUntrackedFiles)" != "false" ] &&
           git ls-files --others --exclude-standard --error-unmatch -- '*' >/dev/null 2>/dev/null
        then
            u="%${ZSH_VERSION+%}"
        fi

        if [ -n "${GIT_PS1_SHOWUPSTREAM-}" ]; then
            __git_ps1_show_upstream
        fi
    fi

    local z="${GIT_PS1_STATESEPARATOR-" "}"

    # NO color option unless in PROMPT_COMMAND mode
    if [ $pcmode = yes ] && [ -n "${GIT_PS1_SHOWCOLORHINTS-}" ]; then
        __git_ps1_colorize_gitstring
    fi

    b=${b##refs/heads/}
    if [ $pcmode = yes ] && [ $ps1_expanded = yes ]; then
        __git_ps1_branch_name=$b
        b="\${__git_ps1_branch_name}"
    fi

    local f="$w$i$s$u"
    local gitstring="$c$b${f:+$z$f}$r$p"

    if [ $pcmode = yes ]; then
        if [ "${__git_printf_supports_v-}" != yes ]; then
            gitstring=$(printf -- "$printf_format" "$gitstring")
        else
            printf -v gitstring -- "$printf_format" "$gitstring"
        fi
        PS1="$ps1pc_start$gitstring$ps1pc_end"
    else
        printf -- "$printf_format" "$gitstring"
    fi
}