#!/bin/sh
# Copyright (c) 2012 Jani Nikula
# License: same as notmuch

# Predefined queries. See http://nmbug.tethera.net/status/
QUERY_MAYBE_READY="tag:notmuch::patch and not tag:notmuch::pushed and not tag:notmuch::obsolete and not tag:notmuch::wip and not tag:notmuch::stale and not tag:notmuch::contrib and not tag:notmuch::moreinfo and not tag:notmuch::python and not tag:notmuch::vim and not tag:notmuch::wontfix and not tag:notmuch::needs-review"

QUERY_REVIEW="tag:notmuch::patch and not tag:notmuch::pushed and not tag:notmuch::obsolete and not tag:notmuch::stale and not tag:notmuch::wontfix and (tag:notmuch::moreinfo or tag:notmuch::needs-review)"

# Defaults for command line options
# local
LOCAL_BRANCH="firehose-`date +%F.%H%M%S`"
FORCE_LOCAL=
GIT_CHECKOUT_MODE="-b"
QUERY="$QUERY_MAYBE_READY"
# upstream
DO_FETCH=
UPSTREAM_NAME="origin"
UPSTREAM_BRANCH="master"
# pushing
DO_PUSH=
GIT_PUSH_FORCE=
REMOTE_BRANCH="firehose"
REMOTE_NAME="firehose"
# conflict management
DO_NON_INCREMENTAL=
DO_KEEP_GOING=
DO_TAG=
CONFLICT_TAG="maybe-stale"

usage()
{
    cat <<EOF
nmfirehose [options ...]

Apply patches on top of an upstream repository from a notmuch mail store based
on notmuch queries.

Run in a git tree with suitable remote(s) set ($UPSTREAM_NAME is the default
upstream remote).

An email thread is expected to contain exactly one patch series. Multiple series
in a thread are considered one series. The patch order in a series is based on
notmuch search --sort=oldest-first.

Local:
  -l LOCAL_BRANCH     local branch to use (default: $LOCAL_BRANCH)
  -F                  force use local branch even if existing
  -q QUERY_NAME       predefined query to use, see below (default: maybe-ready)
  -Q QUERY            query to use (default: same as -q maybe-ready)

Upstream baseline to apply patches on:
  -f                  fetch upstream first
  -u UPSTREAM_BRANCH  upstream branch (default: $UPSTREAM_BRANCH)
  -U UPSTREAM_NAME    upstream remote name (default: $UPSTREAM_NAME)

Pushing the result:
  -p                  push the result afterwards
  -P                  force push the result afterwards
  -r REMOTE_BRANCH    remote branch to push to (default: $REMOTE_BRANCH)
  -R REMOTE_NAME      remote name to push to (default: $REMOTE_NAME)

Conflict management:
  -n                  non-incremental, apply each series on upstream
  -k                  keep going after conflicts without reverting series
  -t                  tag conflicting patches
  -T TAG              tag for conflicting patches (default: $CONFLICT_TAG)

Predefined queries:

maybe-ready = $QUERY_MAYBE_READY

review = $QUERY_REVIEW
EOF
    exit 0
}

error()
{
    echo "nmfirehose: $*" >&2
    exit 1
}

set -eu

while getopts l:Fq:Q:fu:U:pPr:R:nktT:h opt; do
    case "$opt" in
	# local
	l) LOCAL_BRANCH="$OPTARG";;
	F) FORCE_LOCAL=1; GIT_CHECKOUT_MODE="-B";;
	q)
	    if [ "$OPTARG" = "maybe-ready" ]; then
		QUERY="$QUERY_MAYBE_READY"
	    elif [ "$OPTARG" = "review" ]; then
		QUERY="$QUERY_REVIEW"
	    else
		error "unknown predefined query '$OPTARG'"
	    fi
	    ;;
	Q) QUERY="$OPTARG";;
	# upstream
	f) DO_FETCH=1;;
	u) UPSTREAM_BRANCH="$OPTARG";;
	U) UPSTREAM_NAME="$OPTARG";;
	# pushing
	p) DO_PUSH=1;;
	P) DO_PUSH=1; GIT_PUSH_FORCE="--force";;
	r) REMOTE_BRANCH="$OPTARG";;
	R) REMOTE_NAME="$OPTARG";;
	# conflict management
	n) DO_NON_INCREMENTAL=1;;
	k) DO_KEEP_GOING=1;;
	t) DO_TAG=1;;
	T) CONFLICT_TAG="$OPTARG";;
	# help
	h) usage;;
	\?) error "try -h for usage";;
    esac
done
shift `expr $OPTIND - 1`

if [ "$#" != "0" ]; then
    error "unsupported positional argument(s) '$*'; try -h for usage"
fi

if [ -n "$DO_PUSH" -a -n "$DO_NON_INCREMENTAL" ]; then
    error "non-incremental push is not supported"
fi

# NOTE: This does not catch all the ways users can shoot themselves in the feet.
if ! git diff --quiet || ! git diff --cached --quiet; then
    error "uncommitted local changes"
fi

# FIXME: Check that we're in a git-dir and work-dir and not bare. git rev-parse.

if [ -n "$DO_FETCH" ]; then
    git fetch $UPSTREAM_NAME
fi

RESET_HEAD=$UPSTREAM_NAME/$UPSTREAM_BRANCH

# NOTE: This does not catch all the ways users can shoot themselves in the feet.
if [ "`git name-rev --name-only HEAD`" = "$LOCAL_BRANCH" ]; then
    if [ -n "$FORCE_LOCAL" ]; then
	git reset --hard $RESET_HEAD
    else
	error "already on branch $LOCAL_BRANCH, try -F to force"
    fi
else
    git checkout $GIT_CHECKOUT_MODE $LOCAL_BRANCH $UPSTREAM_NAME/$UPSTREAM_BRANCH
fi

cleanup()
{
    rv=$?
    # FIXME: could do more clever things here
    git am --abort >/dev/null 2>&1
    exit $rv
}
trap cleanup 1 2 3 6 15

THREADS=`notmuch search --output=threads --sort=oldest-first $QUERY`

for thread in $THREADS; do
    MESSAGES=`notmuch search --output=messages --sort=oldest-first $QUERY AND $thread`
    subject=

    for message in $MESSAGES; do
	if [ -z "$subject" ]; then
	    subject=`notmuch show --format=raw $message | grep -m 1 "^Subject: " | sed 's/^Subject: //'`
	    echo "$thread: \"$subject\":"
	fi

	if notmuch show --format=mbox $message | git am - >/dev/null 2>&1; then
	    echo "+ $message applied."
	else
	    git am --abort

	    if [ -n "$DO_TAG" -a -n "$CONFLICT_TAG" ]; then
		notmuch tag +$CONFLICT_TAG -- $message
	    fi

	    if [ -n "$DO_KEEP_GOING" ]; then
		echo "$message conflicts, skipping."
	    else
		if [ -n "$DO_NON_INCREMENTAL" ]; then
		    echo "- $message conflicts."
		    # branch will be reset anyway
		else
		    echo "- $message conflicts, reverting thread."
		    git reset --hard $RESET_HEAD
		fi
		break
	    fi
	fi
    done

    if [ -n "$DO_NON_INCREMENTAL" ]; then
	echo "non-incremental mode, reverting to $RESET_HEAD."
	git reset --hard $RESET_HEAD
    else
	RESET_HEAD=`git rev-parse HEAD`
    fi
done

if [ -n "$DO_PUSH" ]; then
    git push $GIT_PUSH_FORCE $REMOTE_NAME $LOCAL_BRANCH:$REMOTE_BRANCH
fi