#!/usr/bin/tclsh

# read include file
set include_pathname [lindex $argv 0]
if {[catch {
	set source [exec cat $include_pathname]
}]} {
	puts stderr ""
	puts stderr "Assign correct ifndef-define name to header file."
	puts stderr "The name is derived from the location of the"
	puts stderr "header file relative to directory from which"
	puts stderr "this program is executed."
	puts stderr ""
	puts stderr "\n  usage: fix_include_ifndef <include_file>\n"
	exit 0
}

puts stderr "Fixing ifndef header for $include_pathname"

# convert pathname to ifndef string
regsub {^./} $include_pathname "" ifndef_name
set ifndef_name [string toupper $ifndef_name]
regsub -all {/} $ifndef_name {__} ifndef_name
regsub -all {\.} $ifndef_name {_} ifndef_name
regsub -all {\-} $ifndef_name {_} ifndef_name
set ifndef_name "_$ifndef_name\_"

set lines [split $source "\n"]
set state comment_header_begin
set i 0
set output ""

proc out {txtline} {
	global output
	append output "$txtline\n"
}

foreach line $lines {
	incr i

	if {$state == "comment_header_begin"} {
		if {[regexp {^/*} $line]} {
			set state comment_header
			out $line
			continue
		} else {
			puts stderr "Error (line $i): missing comment header"
			exit -1;
		}
	}

	if {$state == "comment_header"} {
		if {[regexp {^ \*/} $line]} {
			set state empty_line_after_comment_header
			out $line
			continue;
		}
		if {[regexp {^ \*[^/]*} $line]} {
			out $line
			continue
		}
		puts "Error (line $i): non-complient comment header"
		exit -1;
	}

	if {$state == "empty_line_after_comment_header"} {
		if {![regexp {^$} $line]} {
			puts "Error (line $i): no empty line after comment header"
			exit -1;
		}
		set state license_header_begin
		out $line
		continue
	}

	if {$state == "license_header_begin"} {
		if {[regexp {^/*} $line]} {
			set state license_header
			out $line
			continue
		} else {
			puts stderr "Error (line $i): missing license header"
			exit -1;
		}
	}

	if {$state == "license_header"} {
		if {[regexp {^ \*/} $line]} {
			set state empty_line_after_license_header
			out $line
			continue;
		}
		if {[regexp {^ \*[^/]*} $line]} {
			out $line
			continue
		}
		puts "Error (line $i): non-complient license header"
		exit -1;
	}

	if {$state == "empty_line_after_license_header"} {
		if {![regexp {^$} $line]} {
			puts "Error (line $i): no empty line after license header"
			exit -1;
		}
		set state ifndef
		out $line
		continue
	}

	if {$state == "ifndef"} {
		if {![regexp {^#ifndef} $line]} {
			puts "Error (line $i): expected \"#ifndef\""
			exit -1;
		}

		regsub {^.*$} $line "#ifndef $ifndef_name" line
		out $line
		set state define
		continue
	}

	if {$state == "define"} {
		if {![regexp {^#define} $line]} {
			puts "Error (line $i): expected \"#define\""
			exit -1;
		}

		regsub {^.*$} $line "#define $ifndef_name" line
		out $line
		set state source_main
		continue
	}

	out $line
}

# remove empty lines at the end of the header file
while {[regexp "\n$" $output]} {
	regsub "\n$" $output "" output
}

if {![regexp "\n#endif\[^\n\]*\$" $output]} {
	puts stderr "Error: last line is no \"#endif\""
	exit -1
}

regsub "\n#endif\[^\n\]*\$" $output "\n#endif /* $ifndef_name */" output

# write result back to include file
set fh [open $include_pathname "w"]
puts $fh $output
close $fh