#!/bin/bash
################################################################################
# Update the local binary files with the uversion files from the fossil repo.
################################################################################
# 
# Exit Error Codes:
# 
# The exit error codes are based on the /usr/include/sysexits.h for all
# non-zero errors.  An exit code of '0' is success.
#
###############################################################################
#
# Bugs:
# - Nothing to admit
#
###############################################################################
#
# Todo:
# - Removing files is a destructive and should be done only by request (-r)
# - Add more Todo items
#
###############################################################################


###############################################################################
# Variables: Read-Only

########################################
# Error Codes
readonly Error_Data=65        # EX_DATAERR
readonly Error_NoInput=66     # EX_NOINPUT
readonly Error_NoPerm=77      # EX_NOPERM
readonly Error_TempFail=75    # EX_TEMPFAIL
readonly Error_Unavailable=69 # EX_UNAVAILABLE
readonly Error_Usage=64       # EX_USAGE

########################################
# Grep Exit Codes
readonly Grep_Found_Match=0
readonly Grep_No_Match=1
readonly Grep_Error=2

########################################
# Page Viewer
if [ -n "`command -v less 2> /dev/null`" ]
then
	readonly page_viewer="less --no-init --quit-if-one-screen"
elif [ -n "`command -v more 2> /dev/null`" ]
then
	readonly page_viewer="more"
else
	readonly page_viewer=""
fi

########################################
# Project Values
readonly program_name=`basename $0`
readonly project_path=$(fossil info | grep 'local-root:' | sed 's/.*: *\(.*\)[\/]/\1/')


###############################################################################
# Variables: Internal
action=""
export_list=()
file_list=""

###############################################################################
# Variables: Arg Configurable
category_list=""
debug_mode=""
dest_path=""
dry_run=""
make_dirs=""
separator=":"


###############################################################################
main()
{
	for category in $category_list
	do
		export_list=( $(fossil uv ls | grep "$category$separator") )
	done

	if [ -n "$dry_run" ]
	then
		action=ignore
	fi

	if [ -n "$debug_mode" ]
	then
		echo "--- Internally Defined Values ---"
		echo "   page_viewer: \"$page_viewer\""
		echo "  program_name: \"$program_name\""
		echo "  project_path: \"$project_path\""
		echo "        action: \"$action\""
		echo ""
		echo "--- Argument Based Values ---"
		echo " category_list: \"$category_list\""
		echo "     dest_path: \"$dest_path\""
		echo "       dry_run: \"$dry_run\""
		echo "     make_dirs: \"$make_dirs\""
		echo "     separator: \"$separator\""
		exit $Error_TempFail
	fi

	if [ ! -d "$dest_path" ]
	then
		$action mkdir -p "$dest_path"
	fi

	remove_files
	update_files
	export_files
}


################################################################################
# Parse the export name to get the file name
get_export_file()
{
	echo $1 | sed "s_.*$separator\(.*\)_\1_"
}


################################################################################
# Do nothing and do it well
ignore()
{
	echo -n
}


################################################################################
# Compare the currently existing files with the unversioned files (uv_list).
# Any file that is not in the uv_list, should be removed unless those files are
# in the fossil repo.  This covers the use-case of unversioned files being
# deleted or renamed.
remove_files()
{
	if [ ! -d "$dest_path" ]
	then
		return
	fi

	uv_list=$(fossil uv ls)

	for file_path in `find "$dest_path" -not -name '.*' -type f | sed 's|^\./||'`
	do
		# Get the path relative to the project root
		#file=${file_path:${#project_path}+1}

		# if $file_path is in the repo, skip it
		fossil finfo "$file_path" &> /dev/null
		if [ "$?" == "0" -o -L "$file_path" ]
		then
			continue
		fi

		# if $file is not in the $uv_list
		file=$(basename $file_path)
		echo $uv_list | grep "$separator$file" &> /dev/null
		if [ "$?" == "$Grep_No_Match" ]
		then
			echo "Removing  \"$file_path\""
			$action rm -f "$file_path"
		fi
	done
}


################################################################################
# Check the unversioned file list to see if there are any missing files in the
# check-out.  If a file is missing, export it into existance.
export_files()
{
	if [ ! -d "$dest_path" ]
	then
		return
	fi

	for export_file in ${export_list[@]}
	do
		file=$(get_export_file $export_file)
		if [ ! -f "$file" ]
		then
			echo "Exporting \"$export_file\""
			$action fossil uv export "$export_file" "$dest_path/$file"
		fi
	done
}


################################################################################
# If an unversion file already exists, check the timestamps and if the file in
# the repo is newer, replace the old file with a freshly exported file.
update_files()
{
	if [ ! -d "$dest_path" ]
	then
		return
	fi

	cd $dest_path

	for export_file in ${export_list[@]}
	do
		file=$(get_export_file $export_file)

		if [ -f "$file" ]
		then
			timestamp=$(fossil uv list --like "$export_file" | sed 's/.* \(....-..-.. ..:..:..\) .*/\1/')
			repo_time=$(date +"%s" -u -d "$timestamp")

			timestamp=$(stat --format="%y" $file)
			file_time=$(date +"%s" -u -d "$timestamp")

			if [ $repo_time -gt $file_time ]
			then
				echo "Updating  \"$dest_path/$file\""
				$action fossil uv export "$export_file" "$dest_path/$file"
			fi
		fi
	done

	cd - &> /dev/null
}


################################################################################
show_usage()
{
	if [ -n "$page_viewer" ]
	then
		usage | $page_viewer
	else
		usage
	fi
}


################################################################################
usage()
{
	cat <<- USAGE_END
	Usage: $program_name [Options] Category [Category [Category ...]] Dest

	Options:
	  --debug
	    Display the internal values that would be used to create the
	    requested class then exit.

	  -h, --help
	    Show this message and exit.

	  -n, --dry-run
	    Only print what would be done.  No file changes will be made.
	    Note: The destination directory must exist to use this option.

	  -p, --parents
	    Make parent directories as needed.

	  -s, --separator CHAR
	    Specify the character that separates the category name from the
	    file name in the repository.
	    Default: ":"

	Arguments:
	  Category
	    All the files with this category will be exported from the
	    repository.  Multiple categories can be provided.

	  Dest
	    The location of where to place the exported files.  This path can
	    be absolute or relative to the project root directory.  However,
	    the destination MUST be somewhere within the project.

	USAGE_END
}


###############################################################################
# Parse the args
arg_list=()

while [ "$1" != "" ]
do
	case $1 in
		--debug)
			debug_mode="yes"
			;;
		-h|--help)
			show_usage
			exit 0
			;;
		-n|--dry-run)
			dry_run="yes"
			;;
		-p|--parents)
			make_dirs="yes"
			;;
		-s|--separator)
			shift
			separator="$1"
			;;
		-*)
			echo "Error: Option \"$1\" is not supported."
			echo "Use \"-h\" for help:"
			echo "  $program_name -h"
			exit $Error_Usage
			;;
		*)
			arg_list+=($1)
			;;
	esac
	shift
done

# Bash Array Syntax
# ${array_name[@]}       Get all elements
# ${#array_name[@]}      Count all elements
# ${array_name[@]:I:N}   Get N elements starting at I

category_list=${arg_list[@]:0:${#arg_list[@]}-1}
dest_path=${arg_list[@]:${#arg_list[@]}-1:1}

###############################################################################
# Make sure that all required information is present and valid

### Category ###

if [ -z "$category_list" ]
then
	echo "Error: No categories were provided"
	echo "Use \"-h\" for help:"
	echo "	$program_name -h"
	exit $Error_Usage
fi

uv_list=$(fossil uv ls)
for category in $category_list
do
	echo $uv_list | grep "$category$separator" &> /dev/null
	if [ "$?" == "$Grep_No_Match" ]
	then
		echo "Error: Category Not Found: $category"
		echo "Use \"-h\" for help:"
		echo "	$program_name -h"
		exit $Error_Usage
	fi
done

### Destination ###

if [ -z "$dest_path" ]
then
	echo "Error: No destination path was provided"
	echo "Use \"-h\" for help:"
	echo "	$program_name -h"
	exit $Error_Usage
fi

if [[ $dest_path != /* ]]
then
	dest_path="$project_path/$dest_path"
fi

dest_path=$(readlink --canonicalize $dest_path)

echo $dest_path | grep "^$project_path" &> /dev/null
if [ "$?" == "$Grep_No_Match" ]
then
	echo "Error: Invalid destination, not within project root"
	echo "Use \"-h\" for help:"
	echo "	$program_name -h"
	exit $Error_Usage
fi

if [ ! -d "$dest_path" -a -z "$make_dirs" ]
then
	echo "Error: Invalid destination, \"$dest_path\" does not exist"
	echo "Use \"-h\" for help:"
	echo "	$program_name -h"
	exit $Error_Usage
fi

### Dry Run ###

if [ ! -d "$dest_path" -a -n "$dry_run" ]
then
	echo "Error: Destination must exist to use --dry-run (-n)"
	echo "Use \"-h\" for help:"
	echo "	$program_name -h"
	exit $Error_Usage
fi

###############################################################################
# Everything is now ready
main
exit 0