#!/usr/bin/env bash
#
# This function retries Git operations to avoid failure in case remote is borked
#
improved_git() {
	local real_git
	real_git="$(command -v git)"
	local retries=3
	local delay=10
	local count=0
	while [ $count -lt $retries ]; do
		run_host_command_logged_raw "$real_git" --no-pager "$@" && return 0 # this gobbles up errors, but returns if OK, so everything after is error
		count=$((count + 1))
		display_alert "improved_git try $count failed, retrying in ${delay} seconds" "git $*" "warn"
		sleep $delay
	done
	display_alert "improved_git, too many retries" "git $*" "err"
	return 17 # explode with error if this is reached, "too many retries"
}

# Not improved, just regular, but logged "correctly".
regular_git() {
	run_host_command_logged_raw git --no-pager "$@"
}

# avoid repeating myself too much
function improved_git_fetch() {
	improved_git fetch --progress --verbose --no-auto-maintenance "$@"
}

# workaround new limitations imposed by CVE-2022-24765 fix in git, otherwise  "fatal: unsafe repository"
function git_ensure_safe_directory() {
	if [[ -n "$(command -v git)" ]]; then
		local git_dir="$1"
		display_alert "git: Marking directory as safe" "$git_dir" "debug"
		run_host_command_logged git config --global --add safe.directory "$git_dir"
	else
		display_alert "git not installed" "a true wonder how you got this far without git - it will be installed for you" "warn"
	fi
}

# fetch_from_repo <url> <directory> <ref> <ref_subdir>
# <url>: remote repository URL
# <directory>: local directory; subdir for branch/tag will be created
# <ref>:
#	branch:name
#	tag:name
#	head(*)
#	commit:hash
#
# *: Implies ref_subdir=no
#
# <ref_subdir>: "yes" to create subdirectory for tag or branch name
#
fetch_from_repo() {
	display_alert "fetch_from_repo" "$*" "git"
	local url=$1
	local dir=$2
	local ref=$3
	local ref_subdir=$4
	local git_work_dir

	# Set GitHub mirror before anything else touches $url
	url=${url//'https://github.com/'/$GITHUB_SOURCE'/'}

	# The 'offline' variable must always be set to 'true' or 'false'
	local offline=false
	if [[ "${OFFLINE_WORK}" == "yes" ]]; then
		offline=true
	fi

	[[ -z $ref || ($ref != tag:* && $ref != branch:* && $ref != head && $ref != commit:*) ]] && exit_with_error "Error in configuration"
	local ref_type=${ref%%:*} ref_name=${ref##*:}
	if [[ $ref_type == head ]]; then
		ref_name=HEAD
	fi

	display_alert "Getting sources from Git" "$dir $ref_name" "info"

	local workdir=$dir
	if [[ $ref_subdir == yes ]]; then
		workdir=$dir/$ref_name
	fi

	git_work_dir="${SRC}/cache/sources/${workdir}"

	# if GIT_FIXED_WORKDIR has something, ignore above logic and use that directly.
	if [[ "${GIT_FIXED_WORKDIR}" != "" ]]; then
		display_alert "GIT_FIXED_WORKDIR is set to" "${GIT_FIXED_WORKDIR}" "git"
		git_work_dir="${SRC}/cache/sources/${GIT_FIXED_WORKDIR}"
	fi

	mkdir -p "${git_work_dir}" || exit_with_error "No path or no write permission" "${git_work_dir}"

	cd "${git_work_dir}" || exit

	display_alert "Git working dir" "${git_work_dir}" "git"

	git_ensure_safe_directory "${git_work_dir}"

	local expected_origin_url actual_origin_url
	expected_origin_url="$(echo -n "${url}" | sed 's/^.*@//' | sed 's/^.*\/\///')"

	# Make sure the origin matches what is expected. If it doesn't, clean up and start again.
	if [[ "$(git rev-parse --git-dir)" == ".git" ]]; then
		actual_origin_url="$(git config remote.origin.url | sed 's/^.*@//' | sed 's/^.*\/\///')"
		if [[ "${expected_origin_url}" != "${actual_origin_url}" ]]; then
			display_alert "Remote git URL does not match, deleting working copy" "${git_work_dir} expected: '${expected_origin_url}' actual: '${actual_origin_url}'" "warn"
			cd "${SRC}" || exit 3                                                                            # free up cwd
			run_host_command_logged rm -rf "${git_work_dir}"                                                 # delete the dir
			mkdir -p "${git_work_dir}" || exit_with_error "No path or no write permission" "${git_work_dir}" # recreate
			cd "${git_work_dir}" || exit                                                                     #reset cwd
		fi
	fi

	local do_add_origin="no"

	if [[ "$(git rev-parse --git-dir)" != ".git" ]]; then
		# Dir is not a git working copy. Make it so;
		# If callback is defined, call it. Give it the dir as param. The rest it will read from environment.
		# If not callback defined, do an init, and schedule a fetch.

		if [[ $(type -t ${GIT_INIT_REPO_HOOK} || true) == function ]]; then
			display_alert "Delegating to ${GIT_INIT_REPO_HOOK}()" "git init: $dir $ref_name" "debug"
			${GIT_INIT_REPO_HOOK} "${git_work_dir}"
		else
			display_alert "Initializing empty git local copy" "git init: $dir $ref_name"
			regular_git init -q --initial-branch="armbian_unused_initial_branch" .
		fi

		offline=false          # Force online, we'll need to fetch.
		do_add_origin="yes"    # Just created the repo, it needs an origin later.
	fi

	local changed=false

	# get local hash; might fail
	local local_hash
	local_hash=$(git rev-parse @ 2> /dev/null || true) # Don't fail nor output anything if failure

	# when we work offline we simply return the sources to their original state
	if ! $offline; then

		case $ref_type in
			branch)
				# TODO: grep refs/heads/$name
				local remote_hash
				remote_hash=$(git ls-remote -h "${url}" "$ref_name" | head -1 | cut -f1)
				[[ -z $local_hash || "${local_hash}" != "a${remote_hash}" ]] && changed=true
				;;
			tag)
				local remote_hash
				remote_hash=$(git ls-remote -t "${url}" "$ref_name" | cut -f1)
				if [[ -z $local_hash || "${local_hash}" != "${remote_hash}" ]]; then
					remote_hash=$(git ls-remote -t "${url}" "$ref_name^{}" | cut -f1)
					[[ -z $remote_hash || "${local_hash}" != "${remote_hash}" ]] && changed=true
				fi
				;;
			head)
				local remote_hash
				remote_hash=$(git ls-remote "${url}" HEAD | cut -f1)
				[[ -z $local_hash || "${local_hash}" != "${remote_hash}" ]] && changed=true
				;;
			commit)
				[[ -z $local_hash || $local_hash == "@" ]] && changed=true
				;;
		esac

		display_alert "Git local_hash vs remote_hash" "${local_hash} vs ${remote_hash}" "git"

	fi # offline

	local checkout_from="HEAD" # Probably best to use the local revision?

	if [[ "${changed}" == "true" ]]; then

		if [[ $(type -t ${GIT_PRE_FETCH_HOOK} || true) == function ]]; then
			display_alert "Delegating to ${GIT_PRE_FETCH_HOOK}()" "before git fetch" "debug"
			${GIT_PRE_FETCH_HOOK} "${git_work_dir}" "${url}" "$ref_type" "$ref_name"
		fi

		if [[ "${do_add_origin}" == "yes" ]]; then
			regular_git remote add origin "${url}"
		fi

		# remote was updated, fetch and check out updates, but not tags; tags pull their respective commits too, making it a huge fetch.
		display_alert "Fetching updates from origin" "$dir $ref_name"
		case $ref_type in
			branch | commit) improved_git_fetch --no-tags origin "${ref_name}" ;;
			tag) improved_git_fetch --no-tags origin tags/"${ref_name}" ;;
			head) improved_git_fetch --no-tags origin HEAD ;;
		esac
		display_alert "Origin fetch completed, working copy size" "$(du -h -s | awk '{print $1}')" "git"
		checkout_from="FETCH_HEAD"
	fi

	# should be declared in outside scope, so can be read.
	checked_out_revision_ts="$(git log -1 --pretty=%ct "${checkout_from}")"             # unix timestamp of the commit date
	checked_out_revision_mtime="$(date +%Y%m%d%H%M%S -d "@${checked_out_revision_ts}")" # convert timestamp to local date/time
	display_alert "checked_out_revision_mtime set!" "${checked_out_revision_mtime} - ${checked_out_revision_ts}" "git"

	display_alert "Cleaning git dir" "$(git status -s 2> /dev/null | wc -l) files" # working directory is not clean, show it

	#fasthash_debug "before git checkout of $dir $ref_name" # fasthash interested in this
	regular_git checkout -f -q "${checkout_from}" # Return the files that are tracked by git to the initial state.

	#fasthash_debug "before git clean of $dir $ref_name"
	regular_git clean -q -d -f # Files that are not tracked by git and were added when the patch was applied must be removed.

	if [[ -f .gitmodules ]]; then
		if [[ "${GIT_SKIP_SUBMODULES}" == "yes" ]]; then
			display_alert "Skipping submodules" "GIT_SKIP_SUBMODULES=yes" "debug"
		else
			display_alert "Updating submodules" "" "ext"
			# FML: http://stackoverflow.com/a/17692710
			for i in $(git config -f .gitmodules --get-regexp path | awk '{ print $2 }'); do
				cd "${git_work_dir}" || exit
				local surl sref
				surl=$(git config -f .gitmodules --get "submodule.$i.url")
				sref=$(git config -f .gitmodules --get "submodule.$i.branch" || true)
				if [[ -n $sref ]]; then
					sref="branch:$sref"
				else
					sref="head"
				fi
				# @TODO: in case of the bundle stuff this will fail terribly
				fetch_from_repo "$surl" "$workdir/$i" "$sref"
			done
		fi
	fi

	display_alert "Final working copy size" "$(du -h -s | awk '{print $1}')" "git"
	#fasthash_debug "at the end of fetch_from_repo $dir $ref_name"
}