#!/usr/bin/awk -f

# TODO
#  custom compilers
#  allow overrides
#  compilation options
#  configuration options

BEGIN {
	default_conf = "release"
	configs["debug"] = "-Og -g3"
	configs["release"] = "-Os -s -flto"
}

$1 == "default" { default_conf = $2 }

$1 == "bin" { type[$2] = "bin" }
$2 == "deps" {
	for (i = 3; i <= NF; i++) {
		deps[$i] = 1
		depend[$1] = depend[$1] " " $i
	}
}
$2 == "cc" || $2 == "cxx" {
	for (i = 3; i <= NF; i++) {
		build[$i] = $2
		need[$1, $i] = 1
	}
}

END {
	print "#!/bin/sh"
	print "# this file is automatically generated by cconf; do not edit it by hand"
	print "set -e"
	print "error=false"
	printf "\n"

	print "printf 'Searching dependencies...\\n'"
	printf "for dep in"
	for (dep in deps) printf " %s", dep
	print "; do"
	print "  if ! pkg-config \"$dep\"; then"
	print "    printf 'Error: dependency %s not found\\n' \"$dep\""
	print "    error=true"
	print "  fi"
	print "done"
	printf "\n"

	print "found=false"
	print "printf 'Selecting C compiler... '"
	print "for cc in \"$CC\" gcc clang; do"
	print "  if which \"$cc\"; then"
	print "    CC=$cc"
	print "    BIN=$cc # may be overriden by $CXX later"
	print "    found=true"
	print "    break"
	print "  fi"
	print "done"
	print "if ! $found; then"
	print "  printf 'no GNU-style C compiler found.\\nYou may want to set $CC.\\n'"
	print "  error=true"
	print "fi"
	printf "\n"

	print "found=false"
	print "printf 'Selecting C++ compiler... '"
	print "for cxx in \"$CXX\" g++ clang++; do"
	print "  if which \"$cxx\"; then"
	print "    CXX=$cxx"
	print "    BIN=$cxx"
	print "    found=true"
	print "    break"
	print "  fi"
	print "done"
	print "if ! $found; then"
	print "  printf 'no GNU-style C++ compiler found.\\nYou may want to set $CXX.\\n'"
	print "  error=true"
	print "fi"
	printf "\n"

	print "$error && exit 1"
	printf "\n"

	for (target in depend) {
		print "CFLAGS_DEPS_" target "=$(pkg-config --cflags" depend[target] ")"
		print "LDFLAGS_DEPS_" target "=$(pkg-config --cflags" depend[target] ")"
	}
	printf "\n"

	print "cat > build.ninja <<EOF"
	print "# this file is generated by configure; do not edit"
	print "builddir = build"
	printf "\n"

	print "rule cc"
	print "  description = $CC \\$in"
	print "  command = $CC -MD -MF \\$out.d \\$cflags -o \\$out -c \\$in"
	print "  deps = gcc"
	print "  depfile = \\$out.d"
	printf "\n"

	print "rule cxx"
	print "  description = $CXX \$in"
	print "  command = $CXX -MD -MF \\$out.d \\$cflags -o \\$out -c \\$in"
	print "  deps = gcc"
	print "  depfile = \\$out.d"
	printf "\n"

	print "rule bin"
	print "  description = $BIN \\$out"
	print "  command = $BIN -o \\$out \\$in \\$ldflags"
	printf "\n"

	print "rule clean"
	print "  description = CLEAN"
	print "  command = rm -r \\$in"
	printf "\n"

	print "rule configure"
	print "  command = $0"
	print "  generator = true"
	printf "\n"

	print "build build.ninja: configure $0"
	printf "\n"

	printf "build clean: clean \\$builddir"
	for (config in configs) for (target in type) printf " %s.%s", target, config
	printf "\n"

	for (config in configs) {
		printf "build %s: phony", config
		for (target in type) printf " %s.%s", target, config
		printf "\n"
		if (config == default_conf) print "default " config
		printf "\n"

		for (target in type) {
			for (i in srcs) delete srcs[i]

			printf "build %s.%s: %s", target, config, type[target]
			for (source in build) {
				if (!((target, source) in need)) continue
				object = "\\$builddir/" config "/" target "/" source
				sub(/\.c(pp)?$/, ".o", object)
				srcs[source] = object
				printf " %s", object
			}
			printf "\n"
			print "  ldflags = $LDFLAGS_" config " $LDFLAGS_DEPS_" target
			printf "\n"
			for (source in srcs) {
				object = srcs[source]
				print "build " object ": " build[source] " " source
				print "  cflags = $CFLAGS_" config " $CFLAGS_DEPS_" target
				printf "\n"
			}
		}
	}

	print "EOF"
}