#!/usr/bin/env bash
#
#  BLIS    
#  An object-based framework for developing high-performance BLAS-like
#  libraries.
#
#  Copyright (C) 2014, The University of Texas at Austin
#
#  Redistribution and use in source and binary forms, with or without
#  modification, are permitted provided that the following conditions are
#  met:
#   - Redistributions of source code must retain the above copyright
#     notice, this list of conditions and the following disclaimer.
#   - Redistributions in binary form must reproduce the above copyright
#     notice, this list of conditions and the following disclaimer in the
#     documentation and/or other materials provided with the distribution.
#   - Neither the name(s) of the copyright holder(s) nor the names of its
#     contributors may be used to endorse or promote products derived
#     from this software without specific prior written permission.
#
#  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
#  "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
#  LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
#  A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
#  HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
#  SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
#  LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
#  DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
#  THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
#  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
#  OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#
#

#
# -- Helper functions ----------------------------------------------------------
#

print_usage()
{
	# Echo usage info.
	echo " "
	echo " ${script_name}"
	echo " "
	echo " Field G. Van Zee"
	echo " "
	echo " Generate a monolithic header by recursively replacing all #include"
	echo " directives in a selected file with the contents of the header files"
	echo " they reference."
	echo " "
	echo " Usage:"
	echo " "
	echo "   ${script_name} header header_out temp_dir dir_list"
	echo " "
	echo " Arguments:"
	echo " "
	echo "   header        The filepath to the top-level header, which is the file"
	echo "                 that will #include all other header files."
	echo " "
	echo "   header_out    The filepath of the file into which the script will output"
	echo "                 the monolithic header."
	echo " "
	echo "   temp_dir      A directory in which temporary files may be created."
	echo " "
	echo "   dir_list      The list of directory paths in which to search for the"
	echo "                 headers that are #included by 'header'. By default, these"
	echo "                 directories are scanned for .h files, but sub-directories"
	echo "                 within the various directories are not inspected. If the"
	echo "                 -r option is given, these directories are recursively"
	echo "                 scanned. In either case, the subset of directories scanned"
	echo "                 that actually contains .h files is then searched whenever"
	echo "                 a #include directive is encountered in 'header' (or any"
	echo "                 file subsequently #included). If a referenced header file"
	echo "                 is not found, the #include directive is left untouched and"
	echo "                 translated directly into 'header_out'."
	echo " "
	echo " The following options are accepted:"
	echo " "
	echo "   -r          recursive"
	echo "                 Scan the directories listed in 'dir_list' recursively when"
	echo "                 searching for .h header files. By default, the directories"
	echo "                 are not searched recursively."
	echo " "
	echo "   -c          strip C-style comments"
	echo "                 Strip comments enclosed in /* */ delimiters from the"
	echo "                 output, including multi-line comments. By default, C-style"
	echo "                 comments are not stripped."
	echo " "
	echo "   -o SCRIPT   output script name"
	echo "                 Use SCRIPT as a prefix when outputting messages instead"
	echo "                 the script's actual name. Useful when the current script"
	echo "                 is going to be called from within another, higher-level"
	echo "                 driver script and seeing the current script's name might"
	echo "                 unnecessarily confuse the user."
	echo " "
	echo "   -v [0|1|2]  verboseness level"
	echo "                 level 0: silent  (no output)"
	echo "                 level 1: default (single character '.' per header)"
	echo "                 level 2: verbose (several lines per header)."
	echo " "
	echo "   -h          help"
	echo "                 Output this information and exit."
	echo " "

	# Exit with non-zero exit status
	exit 1
}

canonicalize_ws()
{
	local str="$1"

	# Remove leading and trailing whitespace.
	str=$(echo -e "${str}" | sed -e 's/^[[:space:]]*//' -e 's/[[:space:]]*$//')

	# Remove duplicate spaces between words.
	str=$(echo -e "${str}" | tr -s " ")

	# Update the input argument.
	echo "${str}"
}

is_word_in_list()
{
    word="$1"
    list="$2"
    rval=""

    for item in ${list}; do

        if [ "${item}" == "${word}" ]; then
            rval="${word}"
            break
        fi
    done

    echo "${rval}"
}

echovo()
{
	if [ "${verbose_flag}" == "1" ]; then

		# Echo the argument string to stderr instead of stdout.
		echo "${output_name}: $1" 1>&2;
	fi
}

echovo_n()
{
	if [ "${verbose_flag}" == "1" ]; then

		# Echo the argument string to stderr instead of stdout.
		echo -n "$1" 1>&2;
	fi
}

echovo_n2()
{
	if [ "${verbose_flag}" == "1" ]; then

		# Echo the argument string to stderr instead of stdout.
		echo "$1" 1>&2;
	fi
}

# ---

echovt()
{
	if [ "${verbose_flag}" == "2" ]; then

		# Echo the argument string to stderr instead of stdout.
		echo "${output_name}: $1" 1>&2;
	fi
}

echovt_n()
{
	if [ "${verbose_flag}" == "2" ]; then

		# Echo the argument string to stderr instead of stdout.
		echo -n "${output_name}: $1" 1>&2;
	fi
}

echovt_n2()
{
	if [ "${verbose_flag}" == "2" ]; then

		# Echo the argument string to stderr instead of stdout.
		echo "$1" 1>&2;
	fi
}

find_header_dirs()
{
	local cur_dirpath sub_items result cur_list item child_list

	# Extract the argument: the current directory, and the list of
	# directories found so far that contain headers.
	cur_dirpath="$1"

	echovt_n "scanning contents of ${cur_dirpath}"

	# Acquire a list of the directory's contents.
	sub_items=$(ls ${cur_dirpath})

	# If there is at least one header present, add the current directory to
	# the list header of directories. Otherwise, the current directory does
	# not contribute to the list returned to the caller.
	result=$(echo ${sub_items} | grep "\.h")

	if [ -n "${result}" ]; then
		cur_list="${cur_dirpath}"
		echovt_n2 " ...found headers"
	else
		cur_list=""
		echovt_n2 ""
	fi

	# Iterate over the list of directory contents.
	for item in ${sub_items}; do

		# Check whether the current item is in the ignore_list. If so, we
		# ignore it.
		result=$(is_word_in_list "${item}" "${ignore_list}")
		if [ -n "${result}" ]; then
			echovt "ignoring directory '${item}'."
			continue
		fi

		# If the current item is a directory, recursively accumulate header
		# directories for that sub-directory.
		if [ -d "${cur_dirpath}/${item}" ]; then

			# Recursively find header directories within the sub-directory
			# ${item} and store the directory list to child_list.
			child_list=$(find_header_dirs "${cur_dirpath}/${item}")

			# Accumulate the sub-directory's header list with the running list
			# of header directories
			cur_list="${cur_list} ${child_list}"
		fi

	done

	# Return the list of header directories.
	echo "${cur_list}"
}

get_header_path()
{
	local filename dirpaths filepath

	filename="$1"
	dirpaths="$2"
	filepath=""

	# Search each directory path for the filename given.
	for dirpath in ${dirpaths}; do

		if [ -f "${dirpath}/${filename}" ]; then

			filepath="${dirpath}/${filename}"
			break
		fi
	done

	# Return the filepath that was found. Note that if no filepath was found
	# in the loop above, the empty string gets returned.
	echo "${filepath}"
}

replace_pass()
{
	local inputfile dirpaths intermfile skipstr commstr result
	local header headerlist header_filepath header_esc subintermfile

	inputfile="$1"
	dirpaths="$2"
	cursp="$3"

	# Set the output filename, which we will return to the caller. Starting
	# with the input filepath, we strip it down to just the filename and
	# reconstruct it with the .interm suffix in temp_dir.
	intermfile="${inputfile##*/}"
	intermfile="${temp_dir}/${intermfile}.interm"

	# This string is inserted after #include directives after having
	# determined that they are not present in the directory tree.
	skipstr="\/\/ skipped"

	# Initialize the list of headers referenced in #include directives
	# found in the current header file.
	headerlist=""

	result=$(grep '^[[:space:]]*#include ' ${inputfile})

	# Only iterate through the file line-by-line if it contains at least
	# one #include directive. If it does not contain any #include directives,
	# then we can leave headerlist initialized to empty and proceed.
	if [ -n "${result}" ]; then

		# Iterate through each line of the header file, accumulating the names of
		# header files referenced in #include directives.
		while read -r curline
		do

			# Check whether the line begins with a #include directive, but ignore
			# the line if it contains the skip string.
			result=$(echo ${curline} | grep '^[[:space:]]*#include ')

			# If the #include directive was found...
			if [ -n "${result}" ]; then

				# Isolate the header filename. We must take care to include all
				# characters that might appear between the "" or <>.
				header=$(echo ${curline} | sed -e "s/#include [\"<]\([a-zA-Z0-9\_\.\/\-]*\)[\">].*/\1/g")

				# Add the header file to a list.
				headerlist=$(canonicalize_ws "${headerlist} ${header}")

			fi
		done < "${inputfile}"
	fi

	if [ -n "${headerlist}" ]; then
		echovt "${cursp}found references to: ${headerlist}"
	else
		echovt "${cursp}no header references found."
	fi

	# Before we go any further, we strip C-style comments from the file,
	# if requested.
	if [ -n "${strip_comments}" ]; then

		# Make a copy of inputfile stripped of its C-style comments and
		# save it to intermfile. This substitution leaves behind a single
		# blank line.
		cat ${inputfile} \
		    | perl -0777 -pe "s/\/\*.*?\*\///gs" \
		    > "${intermfile}"
	else

		# Otherwise, just copy inputfile to intermfile verbatim.
		cp ${inputfile} ${intermfile}
	fi


	# Iterate over each header file found in the previous loop.
	for header in ${headerlist}; do

		# Find the path to the header.
		header_filepath=$(get_header_path ${header} "${dirpaths}")

		# If the header has a slash, escape it so that sed doesn't get confused
		# (since we use '/' as our search-and-replace delimiter).
		header_esc=$(echo "${header}" | sed -e 's/\//\\\//g')

		# If the header file was not found, get_header_path() returns an
		# empty string. This probably means that the header file is a
		# system header and thus we skip it since we don't want to inline
		# the contents of system headers anyway.
		if [ -z "${header_filepath}" ]; then

			echovt "${cursp}could not locate file '${header}'; marking as skipped."

			# Insert a comment after the #include so we know it was ignored.
			# Notice that we mimic the quotes or angle brackets around the
			# header name, whichever pair was used in the input.

			cat ${intermfile} \
			    | sed -e "s/^[[:space:]]*#include \([\"<]\)\(${header_esc}\)\([\">]\).*/#include \1\2\3 ${skipstr}/" \
			    > "${intermfile}.tmp"

			mv "${intermfile}.tmp" ${intermfile}

		else

			echovt "${cursp}located file '${header_filepath}'; recursing."

			# Recursively produce an inlined/flattened intermediate file at
			# ${header_filepath}.
			subintermfile=$(replace_pass ${header_filepath} "${dirpaths}" "${cursp}${nestsp}")

			echovt "${cursp}inserting '${subintermfile}'."

			# Replace the #include directive for the current header file with the
			# contents of that header file, saving the result to a temporary file.
			# We also insert begin and end markers to allow for more readability.
			# NOTE: We use the 'i\...' and 'a\...' notation with '$', which causes
			# bash to interpret '\n' as a newline, as needed for the 'a\' and 'i\'
			# commands in POSIX (e.g. OS X) sed. (GNU sed allows a much more
			# natural usage that does not require the backslash or newline.)
			cat ${intermfile} \
			    | sed -e "/^[[:space:]]*#include \"${header_esc}\"/ {" \
			          -e 'i\'$'\n'"// begin ${header}"$'\n' \
			          -e "r ${subintermfile}" \
			          -e 'a\'$'\n'"// end ${header}"$'\n' \
			          -e "d" \
			          -e "}" \
			    > "${intermfile}.tmp"

			mv "${intermfile}.tmp" ${intermfile}

			echovt "${cursp}removing intermediate file '${subintermfile}'."

			# Remove the recursive call's intermediate file now that it has been
			# inserted into this level's intermediate.
			rm "${subintermfile}"
		fi
	done

	# works, but leaves blank line:
	#cat "test.h" | sed -e "/^#include \"foo.h\"/r foo.h" -e "s///" > "test.new.h"
	# works:
	#cat "test.h" | sed -e '/^#include \"foo.h\"/ {' -e 'r foo.h' -e 'd' -e '}' > "test.new.h"
	# works:
	#cat "test.h" | sed -e '/^#include \"foo.h\"/r foo.h' -e '/^#include \"foo.h\"/d' > "test.new.h"
	#cat zorn/header.h | sed -e '/^#include \"header1.h\"/ {' -e 'i // begin insertion' -e 'r alice/header1.h' -e 'a // end insertion' -e 'd' -e '}'

	echovt "${cursp}header file '${inputfile}' fully processed."
	echovt "${cursp}returning via '${intermfile}'."

	echovo_n "."

	# Return the intermediate filename so the caller knows the name of this
	# invocation's output file.
	echo "${intermfile}"
}

#
# -- main function -------------------------------------------------------------
#

main()
{
	# The name of the script, stripped of any preceding path.
	script_name=${0##*/}

	# The script name to use in informational output. Defaults to ${script_name}.
	output_name=${script_name}

	# Whether or not we should strip C-style comments from the output. (Default
	# is to not strip C-style comments.)
	strip_comments=""

	# Whether or not we search the directories in dir_list recursively. (Default
	# is to not search recursively.)
	recursive_flag=""

	# The list of directories to ignore
	ignore_list="old other temp test testsuite windows"

	# The amount to nest each level of recursion in the output.
	nestsp="  "

	# Process our command line options.
	while getopts ":o:rchv:" opt; do
	    case $opt in
	        o  ) output_name=$OPTARG ;;
	        r  ) recursive_flag="1" ;;
	        c  ) strip_comments="1" ;;
			v  ) verbose_flag=$OPTARG ;;
	        h  ) print_usage ;;
	        \? ) print_usage
	    esac
	done
	shift $(($OPTIND - 1))

	# Make sure that the verboseness level is valid.
	if [ "${verbose_flag}" != "0" ] &&
	   [ "${verbose_flag}" != "1" ] &&
	   [ "${verbose_flag}" != "2" ]; then
		echo "${output_name}: Invalid verboseness argument '${verbose_flag}'." 1>&2;
		exit 1
	fi

	# Print usage if we don't have exactly two arguments.
	if [ $# != "4" ]; then

		print_usage
	fi

	# Acquire the four required arguments:
	# - the input header file,
	# - the output header file,
	# - the temporary directory in which we can write intermediate files,
	# - the list of directories in which to search for the headers
	inputfile="$1"
	outputfile="$2"
	temp_dir="$3"
	dir_list="$4"

	# First, confirm that the directories in dir_list are valid.
	dir_list2=""
	for item in ${dir_list}; do

		# Strip a trailing slash from the path, if it has one.
		item=${item%/}

		echovt_n "checking ${item} "

		if [ -d ${item} ]; then
			echovt_n2 " ...directory exists."
			dir_list2="${dir_list2} ${item}"
		else
			echovt_n2 " ...invalid directory; omitting."
		fi
	done
	dir_list2=$(canonicalize_ws "${dir_list2}")

	# Overwrite the original dir_list with the updated copy that omits
	# invalid directories.
	dir_list="${dir_list2}"

	echovt "check summary:"
	echovt "  accessible directories:"
	echovt "  ${dir_list}"

	# Generate a list of directories (dirpaths) which will be searched whenever
	# a #include directive is encountered. The method by which dirpaths is
	# compiled will depend on whether the recursive flag was given.
	if [ -n "${recursive_flag}" ]; then

		# If the recursive flag was given, we need to recursively scan each
		# directory in dir_list for directories with headers via the
		# function find_header_dirs().

		dirpaths=""
		for item in ${dir_list}; do

			item_dirpaths=$(find_header_dirs ${item})
			dirpaths="${dirpaths} ${item_dirpaths}"
		done
		dirpaths=$(canonicalize_ws "${dirpaths}")

	else

		# If the recursive flag was not given, we can just use dir_list
		# as-is, though we opt to filter out the directories that don't
		# contain .h files.

		dirpaths=""
		for item in ${dir_list}; do

			echovt_n "scanning ${item}"

			# Acquire a list of the directory's contents.
			sub_items=$(ls ${item})

			# If there is at least one header present, add the current directory to
			# the list header of directories.
			result=$(echo ${sub_items} | grep "\.h")
			if [ -n "${result}" ]; then
				dirpaths="${dirpaths} ${item}"
				echovt_n2 " ...found headers."
			else
				echovt_n2 " ...no headers found."
			fi
		done
		dirpaths=$(canonicalize_ws "${dirpaths}")
	fi

	echovt "scan summary:"
	echovt "  headers found in:"
	echovt "  ${dirpaths}"

	echovt "preparing to monolithify '${inputfile}'."

	# Make a copy of the inputfile.
	#cp ${inputfile} ${outputfile}

	echovt "new header will be saved to '${outputfile}'."

	echovo_n "."

	# Recursively substitute headers for occurrences of #include directives.
	intermfile=$(replace_pass ${inputfile} "${dirpaths}" "${nestsp}")

	# Rename the intermediate file(path) to the output file(path).
	mv ${intermfile} ${outputfile}

	echovt "substitution complete."
	echovt "monolithic header saved as '${outputfile}'."

	echovo_n2 "."

	# Exit peacefully.
	return 0
}


# The script's main entry point, passing all parameters given.
main "$@"