#!/usr/bin/env bash

# Copyright (c) 2019, 2023  Teddy Wing
#
# This file is part of Code Review.
#
# Code Review is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# Code Review is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with Code Review. If not, see <https://www.gnu.org/licenses/>.

GIT_ROOT="$(git rev-parse --show-toplevel)"
DATABASE="${GIT_ROOT}/.git/info/code-review.sqlite"

function create_database () {
	sqlite3 "$DATABASE" <<-SQL
		BEGIN TRANSACTION;

		CREATE TABLE IF NOT EXISTS merge_bases (
			id INTEGER PRIMARY KEY,
			head TEXT NOT NULL,
			base TEXT NOT NULL
		);

		COMMIT;
	SQL
}

function create_database_if_not_exists () {
	if [ ! -f "$DATABASE" ]; then
		create_database
	fi
}

function create_merge_base () {
	local head="$1"
	local base="$2"

	sqlite3 "$DATABASE" <<-SQL
		BEGIN TRANSACTION;

		UPDATE merge_bases
		SET base = '$base'
		WHERE head = '$head';

		INSERT INTO merge_bases
			(head, base)
		SELECT
			'$head',
			'$base'
		WHERE (SELECT changes() = 0);

		COMMIT;
	SQL
}

function create_merge_base_from_current () {
	local base="$1"

	create_merge_base "$(current_branch)" "$base"
}

function get_merge_base () {
	local head="$(current_branch)"
	local default_base='master'

	if [ -n "$CODE_REVIEW_BASE" ]; then
		echo "$CODE_REVIEW_BASE"...
		return 0
	fi

	if git config remote.origin.url > /dev/null; then
		default_base='origin/master'
	fi

	sqlite3 "$DATABASE" <<-SQL
		BEGIN TRANSACTION;

		SELECT ifnull(max(base), '$default_base') || '...'
		FROM merge_bases
		WHERE head = '$head'
		LIMIT 1;

		COMMIT;
	SQL
}

function current_branch () {
	git rev-parse --abbrev-ref HEAD
}


create_database_if_not_exists