#define _XOPEN_SOURCE 700
#include <libgen.h>
#include <limits.h>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>

#include "maje.h"

#ifndef PATH_MAX
#ifdef _XOPEN_PATH_MAX
#define PATH_MAX _XOPEN_PATH_MAX
#else
#define PATH_MAX _POSIX_PATH_MAX
#endif
#endif

static void make_header(FILE *makefile, const char *target, struct majeflag *flags, int lib)
{
	fprintf(makefile, ".POSIX:\n\n");
	fprintf(makefile, "# This Makefile was generated by maje\n");
	fprintf(makefile, "# See https://src.kaivo.net/dev/maje/ for more information\n");
	fprintf(makefile, "# Do not edit this Makefile by hand\n\n");

	fprintf(makefile, "CC=c99\n");
	fprintf(makefile, "LD=$(CC)\n");

	fprintf(makefile, "CFLAGS=-Wall -Wextra -Wpedantic -Werror -g");
	for (struct majeflag *flag = flags; flag != NULL; flag = flag->next) {
		if (flag->type == MAJE_CFLAG) {
			fprintf(makefile, " %s", flag->flag);
		}
	}
	fprintf(makefile, "\n");

	fprintf(makefile, "LDFLAGS=");
	for (struct majeflag *flag = flags; flag != NULL; flag = flag->next) {
		if (flag->type == MAJE_LDFLAG) {
			fprintf(makefile, " %s", flag->flag);
		}
	}
	fprintf(makefile, "\n");

	fprintf(makefile, "LDLIBS=");
	for (struct majeflag *flag = flags; flag != NULL; flag = flag->next) {
		if (flag->type == MAJE_LDLIB) {
			fprintf(makefile, " %s", flag->flag);
		}
	}
	fprintf(makefile, "\n");

	fprintf(makefile, "SRCDIR=.\n");
	fprintf(makefile, "OBJDIR=.\n");
	fprintf(makefile, "BINDIR=$(OBJDIR)\n");
	fprintf(makefile, "LIBDIR=$(OBJDIR)\n");
	fprintf(makefile, "DESTDIR=/usr/local\n");
	fprintf(makefile, "\n");

	fprintf(makefile, "all: ");
	if (lib) {
		fprintf(makefile, "$(LIBDIR)/lib%s.a $(LIBDIR)/lib%s.so", target, target);
	} else {
		fprintf(makefile, "$(BINDIR)/%s", target);
	}
	fprintf(makefile, "\n\n");

	fprintf(makefile, "clean:\n");
	fprintf(makefile, "\trm -f $(BINDIR)/%s $(OBJDIR)/*.o\n\n", target);

	fprintf(makefile, "install: $(BINDIR)/%s\n", target);
	if (lib) {
		fprintf(makefile, "\tmkdir -p $(DESTDIR)/lib\n");
		fprintf(makefile, "\tcp $(LIBDIR)/lib%s.{a,so} $(DESTDIR)/lib\n\n", target);
	} else {
		fprintf(makefile, "\tmkdir -p $(DESTDIR)/bin\n");
		fprintf(makefile, "\tcp $(BINDIR)/%s $(DESTDIR)/bin\n\n", target);
	}
}

static void add_object(FILE *makefile, const struct majefile *src, const char *target, int lib)
{
	char *fullobj = strdup(src->path);
	char *obj = basename(fullobj);
	obj[strlen(obj) - 1] = 'o';

	if (lib) {
		fprintf(makefile, "$(LIBDIR)/lib%s.a $(LIBDIR)/lib%s.so: $(OBJDIR)/%s\n", target, target, obj);
	} else {
		fprintf(makefile, "$(BINDIR)/%s: $(OBJDIR)/%s\n", target, obj);
	}

	for (struct majefile *inc = find_includes(src); inc != NULL; inc = inc->next) {
		fprintf(makefile, "$(OBJDIR)/%s: $(SRCDIR)/%s\n",
			obj, inc->path);
	}
	fprintf(makefile, "$(OBJDIR)/%s: $(SRCDIR)/%s\n", obj, src->path);
	fprintf(makefile, "\t@mkdir -p $(@D)\n");
	fprintf(makefile, "\t$(CC) $(CFLAGS) -o $@ -c $(SRCDIR)/%s\n\n", src->path);

	free(fullobj);
}

static char *cwd_basename(void)
{
	static char path[PATH_MAX];
	if (getcwd(path, sizeof(path)) == NULL) {
		return NULL;
	}

	return basename(path);
}

void make_makefile(const char *makepath, struct majefile *sources, const char *target)
{
	FILE *makefile = fopen(makepath, "w");
	if (makefile == NULL) {
		perror("fopen: Makefile");
		return;
	}

	struct majeflag *flags = NULL;
	for (struct majefile *src = sources; src != NULL; src = src->next) {
		flags = add_flags(src, flags);
	}

	int lib = 0;
	if (target == NULL) {
		lib = 1;
		for (struct majeflag *flag = flags; flag != NULL; flag = flag->next) {
			if (flag->type == MAJE_LIB) {
				if (target) {
					fprintf(stderr, "maje: only one MAJE_LIB is supported\n");
					exit(1);
				}
				target = flag->flag;
			}
		}
	}

	if (lib == 1 && target == NULL) {
		target = cwd_basename();
		if (target == NULL) {
			fprintf(stderr, "maje: couldn't determine binary or library name\n");
			exit(1);
		}
	}

	make_header(makefile, target, flags, lib);
	for (struct majefile *src = sources; src != NULL; src = src->next) {
		add_object(makefile, src, target, lib);
	}

	if (lib) {
		fprintf(makefile, "$(LIBDIR)/lib%s.a:\n", target);
		fprintf(makefile, "\t@mkdir -p $(@D)\n");
		fprintf(makefile, "\t$(AR) $(ARFLAGS) $@ $(OBJDIR)/*.o\n\n");

		fprintf(makefile, "$(LIBDIR)/lib%s.so:\n", target);
		fprintf(makefile, "\t@mkdir -p $(@D)\n");
		fprintf(makefile, "\t$(LD) -shared $(LDFLAGS) -o $@ $(OBJDIR)/*.o $(LDLIBS)\n\n");
	} else {
		fprintf(makefile, "$(BINDIR)/%s:\n", target);
		fprintf(makefile, "\t@mkdir -p $(@D)\n");
		fprintf(makefile, "\t$(LD) $(LDFLAGS) -o $@ $(OBJDIR)/*.o $(LDLIBS)\n");
	}

	fclose(makefile);
}