## vim:ft=zsh
## git support by: Frank Terbeck <ft@bewatermyfriend.org>
## Distributed under the same BSD-ish license as zsh itself.

setopt localoptions extendedglob NO_shwordsplit
local gitdir gitbase gitbranch gitaction gitunstaged gitstaged gitsha1 gitmisc
local -i querystaged queryunstaged
local -a git_patches_applied git_patches_unapplied
local -A hook_com

VCS_INFO_git_getaction () {
    local gitdir=$1
    local tmp

    for tmp in "${gitdir}/rebase-apply" \
               "${gitdir}/rebase"       \
               "${gitdir}/../.dotest" ; do
        if [[ -d ${tmp} ]] ; then
            if   [[ -f "${tmp}/rebasing" ]] ; then
                gitaction="rebase"
            elif [[ -f "${tmp}/applying" ]] ; then
                gitaction="am"
            else
                gitaction="am/rebase"
            fi
            return 0
        fi
    done

    for tmp in "${gitdir}/rebase-merge/interactive" \
               "${gitdir}/.dotest-merge/interactive" ; do
        if [[ -f "${tmp}" ]] ; then
            gitaction="rebase-i"
            return 0
        fi
    done

    for tmp in "${gitdir}/rebase-merge" \
               "${gitdir}/.dotest-merge" ; do
        if [[ -d "${tmp}" ]] ; then
            gitaction="rebase-m"
            return 0
        fi
    done

    if [[ -f "${gitdir}/MERGE_HEAD" ]] ; then
        gitaction="merge"
        return 0
    fi

    if [[ -f "${gitdir}/BISECT_LOG" ]] ; then
        gitaction="bisect"
        return 0
    fi

    if [[ -f "${gitdir}/CHERRY_PICK_HEAD" ]] ; then
        if [[ -d "${gitdir}/sequencer" ]] ; then
            gitaction=cherry-seq
        else
            gitaction=cherry
        fi
        return 0
    fi

    if [[ -d "${gitdir}/sequencer" ]] ; then
         gitaction="cherry-or-revert"
         return 0
    fi

    return 1
}

VCS_INFO_git_getbranch () {
    local gitdir=$1 tmp actiondir
    local gitsymref="${vcs_comm[cmd]} symbolic-ref HEAD"

    actiondir=''
    for tmp in "${gitdir}/rebase-apply" \
               "${gitdir}/rebase"       \
               "${gitdir}/../.dotest"; do
        if [[ -d ${tmp} ]]; then
            actiondir=${tmp}
            break
        fi
    done
    if [[ -n ${actiondir} ]]; then
        gitbranch="$(${(z)gitsymref} 2> /dev/null)"
        [[ -z ${gitbranch} ]] && [[ -r ${actiondir}/head-name ]] \
            && gitbranch="$(< ${actiondir}/head-name)"
        [[ -z ${gitbranch} || ${gitbranch} == 'detached HEAD' ]] \
            && gitbranch="$(< ${gitdir}/ORIG_HEAD)"

    elif [[ -f "${gitdir}/MERGE_HEAD" ]] ; then
        gitbranch="$(${(z)gitsymref} 2> /dev/null)"
        [[ -z ${gitbranch} ]] && gitbranch="$(< ${gitdir}/ORIG_HEAD)"

    elif [[ -d "${gitdir}/rebase-merge" ]] ; then
        gitbranch="$(< ${gitdir}/rebase-merge/head-name)"
        if [[ $gitbranch == 'detached HEAD' ]]; then
            # get a sha1
            gitbranch="$(< ${gitdir}/rebase-merge/orig-head)"
        fi

    elif [[ -d "${gitdir}/.dotest-merge" ]] ; then
        gitbranch="$(< ${gitdir}/.dotest-merge/head-name)"

    else
        gitbranch="$(${(z)gitsymref} 2> /dev/null)"

        if [[ $? -ne 0 ]] ; then
            gitbranch="refs/tags/$(${vcs_comm[cmd]} describe --all --exact-match HEAD 2>/dev/null)"

            if [[ $? -ne 0 ]] ; then
                gitbranch="${${"$(< $gitdir/HEAD)"}[1,7]}..."
            fi
        fi
    fi

    return 0
}

VCS_INFO_git_handle_patches () {
    local git_applied_s git_unapplied_s gitmsg git_all
    git_patches_applied=(${(Oa)git_patches_applied})
    git_patches_unapplied=(${(Oa)git_patches_unapplied})
    (( git_all = ${#git_patches_applied} + ${#git_patches_unapplied} ))

    if VCS_INFO_hook 'gen-applied-string' "${git_patches_applied[@]}"; then
        if (( ${#git_patches_applied} )); then
            git_applied_s=${git_patches_applied[1]}
        else
            git_applied_s=""
        fi
    else
        git_applied_s=${hook_com[applied-string]}
    fi
    hook_com=()
    if VCS_INFO_hook 'gen-unapplied-string' "${git_patches_unapplied[@]}"; then
        git_patches_unapplied=${#git_patches_unapplied}
    else
        git_patches_unapplied=${hook_com[unapplied-string]}
    fi

    if (( ${#git_patches_applied} )); then
        zstyle -s ":vcs_info:${vcs}:${usercontext}:${rrn}" patch-format gitmsg || gitmsg="%p (%n applied)"
    else
        zstyle -s ":vcs_info:${vcs}:${usercontext}:${rrn}" nopatch-format gitmsg || gitmsg="no patch applied"
    fi
    hook_com=( applied "${git_applied_s}"     unapplied "${git_patches_unapplied}"
               applied-n ${#git_patches_applied} unapplied-n ${#git_patches_unapplied} all-n ${git_all} )
    if VCS_INFO_hook 'set-patch-format' "${gitmsg}"; then
        zformat -f gitmisc "${gitmsg}" "p:${hook_com[applied]}" "u:${hook_com[unapplied]}" \
                                          "n:${#git_patches_applied}" "c:${#git_patches_unapplied}" "a:${git_all}"
    else
        gitmisc=${hook_com[patch-replace]}
    fi
    hook_com=()
}

gitdir=${vcs_comm[gitdir]}
VCS_INFO_git_getbranch ${gitdir}
gitbase=$( ${vcs_comm[cmd]} rev-parse --show-toplevel )
rrn=${gitbase:t}
if zstyle -t ":vcs_info:${vcs}:${usercontext}:${rrn}" get-revision ; then
    gitsha1=$(${vcs_comm[cmd]} rev-parse --quiet --verify HEAD)
else
    gitsha1=''
fi
gitbranch="${gitbranch##refs/[^/]##/}"

if [[ -z ${gitdir} ]] || [[ -z ${gitbranch} ]] ; then
    return 1
fi

if zstyle -t ":vcs_info:${vcs}:${usercontext}:${rrn}" "check-for-changes" ; then
    querystaged=1
    queryunstaged=1
elif zstyle -t ":vcs_info:${vcs}:${usercontext}:${rrn}" "check-for-staged-changes" ; then
    querystaged=1
fi
if (( querystaged || queryunstaged )) && \
   [[ "$(${vcs_comm[cmd]} rev-parse --is-inside-work-tree 2> /dev/null)" == 'true' ]] ; then
    # Default: off - these are potentially expensive on big repositories
    if (( queryunstaged )) ; then
        ${vcs_comm[cmd]} diff --no-ext-diff --ignore-submodules=dirty --quiet --exit-code ||
            gitunstaged=1
    fi
    if (( querystaged )) ; then
        if ${vcs_comm[cmd]} rev-parse --quiet --verify HEAD &> /dev/null ; then
            ${vcs_comm[cmd]} diff-index --cached --quiet --ignore-submodules=dirty HEAD 2> /dev/null
            (( $? && $? != 128 )) && gitstaged=1
        else
            # empty repository (no commits yet)
            # 4b825dc642cb6eb9a060e54bf8d69288fbee4904 is the git empty tree.
            ${vcs_comm[cmd]} diff-index --cached --quiet --ignore-submodules=dirty 4b825dc642cb6eb9a060e54bf8d69288fbee4904 2>/dev/null
            (( $? && $? != 128 )) && gitstaged=1
        fi
    fi
fi

VCS_INFO_adjust
VCS_INFO_git_getaction ${gitdir}

local patchdir=${gitdir}/patches/${gitbranch}
if [[ -d $patchdir ]] && [[ -f $patchdir/applied ]] \
   && [[ -f $patchdir/unapplied ]]
then
    git_patches_applied=(${(f)"$(< "${patchdir}/applied")"})
    git_patches_unapplied=(${(f)"$(< "${patchdir}/unapplied")"})
    VCS_INFO_git_handle_patches
elif [[ -d "${gitdir}/rebase-merge" ]]; then
    patchdir="${gitdir}/rebase-merge"
    local p
    [[ -f "${patchdir}/done" ]] &&
    for p in ${(f)"$(< "${patchdir}/done")"}; do
        # pick/edit/fixup/squash/reword: Add "$hash $subject" to $git_patches_applied.
        # exec: Add "exec ${command}" to $git_patches_applied.
        # (anything else): As 'exec'.
        p=${p/(#s)(p|pick|e|edit|r|reword|f|fixup|s|squash) /}
        p=${p/(#s)x /exec }
        git_patches_applied+=("$p")
    done
    if [[ -f "${patchdir}/git-rebase-todo" ]] ; then
        git_patches_unapplied=(${(f)"$(grep -v '^$' "${patchdir}/git-rebase-todo" | grep -v '^#')"})
    fi
    VCS_INFO_git_handle_patches
elif [[ -d "${gitdir}/rebase-apply" ]]; then
    # Fake patch names for all but current patch
    patchdir="${gitdir}/rebase-apply"
    local next="${patchdir}/next"
    if [[ -f $next ]]; then
        local cur=$(< $next)
        local p subject
        for ((p = 1; p < cur; p++)); do
            printf -v "git_patches_applied[$p]"  "%04d ?" "$p"
        done
        if [[ -f "${patchdir}/msg-clean" ]]; then
            subject="${$(< "${patchdir}/msg-clean")[(f)1]}"
        elif local this_patch_file
             printf -v this_patch_file "%s/%04d" "${patchdir}" "${cur}"
             [[ -f $this_patch_file ]]
        then
            () {
              local REPLY
              VCS_INFO_patch2subject "${this_patch_file}"
              subject=$REPLY
            }
        fi
        if [[ -f "${patchdir}/original-commit" ]]; then
            if [[ -n $subject ]]; then
                git_patches_applied+=("$(< ${patchdir}/original-commit) $subject")
            else
                git_patches_applied+=("$(< ${patchdir}/original-commit)")
            fi
        else
            if [[ -n $subject ]]; then
                git_patches_applied+=("? $subject")
            else
                git_patches_applied+=("?")
            fi
        fi
        local last="$(< "${patchdir}/last")"
        if (( cur+1 <= last )); then
          git_patches_unapplied=( {$((cur+1))..$last} )
        fi
    fi

    VCS_INFO_git_handle_patches
elif [[ -f "${gitdir}/MERGE_HEAD" ]]; then
    # This is 'git merge --no-commit'
    local -a heads=( ${(@f)"$(<"${gitdir}/MERGE_HEAD")"} )
    local subject;
    # TODO: maybe read up to the first blank line
    IFS='' read -r subject < "${gitdir}/MERGE_MSG"
    # $subject is the subject line of the would-be commit
    # Maybe we can get the subject lines of MERGE_HEAD's commits cheaply?

    local p
    for p in $heads[@]; do
      git_patches_applied+=("$p $subject")
    done
    unset p

    # Not touching git_patches_unapplied

    VCS_INFO_git_handle_patches
elif [[ -f "${gitdir}/CHERRY_PICK_HEAD" ]]; then
    # 'git cherry-pick' without -n, that conflicted.  (With -n, git doesn't
    # record the CHERRY_PICK_HEAD information anywhere, as of git 2.6.2.)
    #
    # ### 'git cherry-pick foo bar baz' only records the "remaining" part of
    # ### the queue in the .git dir: if 'bar' has a conflict, the .git dir 
    # ### has a record of 'baz' being queued, but no record of 'foo' having been
    # ### part of the queue as well.  Therefore, the %n/%c applied/unapplied
    # ### expandos will be memoryless: the "applied" counter will always
    # ### be "1".  The %u/%c tuple will assume the values [(1,2), (1,1), (1,0)],
    # ### whereas the correct sequence would be [(1,2), (2,1), (3,0)].
    local subject
    # TODO: maybe read up to the first blank line
    IFS='' read -r subject < "${gitdir}/MERGE_MSG"
    git_patches_applied=( "$(<${gitdir}/CHERRY_PICK_HEAD) ${subject}" )
    if [[ -f "${gitdir}/sequencer/todo" ]]; then
        # Get the next patches, and remove the one that's in CHERRY_PICK_HEAD.
        git_patches_unapplied=( ${${(M)${(f)"$(<"${gitdir}/sequencer/todo")"}:#pick *}#pick } )
        git_patches_unapplied[1]=()
    else
        git_patches_unapplied=()
    fi
    VCS_INFO_git_handle_patches
else
    gitmisc=''
fi

backend_misc[patches]="${gitmisc}"
VCS_INFO_formats "${gitaction}" "${gitbranch}" "${gitbase}" "${gitstaged}" "${gitunstaged}" "${gitsha1}" "${gitmisc}"
return 0
