#include "lua_dependency_tree.h"
#include "lua_platform.h"
#include "lua_filesystem.h"
#include <iostream>
#include <filesystem>

// From lua
static int msghandler(lua_State* L) {
	if (!lua_isstring(L, 1))  /* 'message' not a string? */
		return 1;  /* keep it intact */
	lua_getfield(L, LUA_GLOBALSINDEX, "debug");
	if (!lua_istable(L, -1)) {
		lua_pop(L, 1);
		return 1;
	}
	lua_getfield(L, -1, "traceback");
	if (!lua_isfunction(L, -1)) {
		lua_pop(L, 2);
		return 1;
	}
	lua_pushvalue(L, 1);  /* pass error message */
	lua_pushinteger(L, 2);  /* skip this function and traceback */
	lua_call(L, 2, 1);  /* call debug.traceback */
	return 1;
}

int main(int argc, char** argv)
{
	const char* exec_file = "lbs.lua";
	int argstart = 1;
	if (argc > 2 && (
		strcmp(argv[1], "--buildscript") == 0 ||
		strcmp(argv[1], "-s") == 0))
	{
		exec_file = argv[2];
		argstart += 2;
	}
	if (!std::filesystem::exists(exec_file))
	{
		fprintf(stderr, "Failed to find buildscript %s to execute\n", exec_file);
		return EXIT_FAILURE;
	}
	
	lua_State* L = luaL_newstate();
	luaL_openlibs(L);
	luaopen_dependency_tree(L);
	luaopen_platform(L);
	luaopen_filesystem(L);
	
	
	luaL_loadfile(L, exec_file);
	for (int i = (argstart+1); i < argc; ++i)
		lua_pushstring(L, argv[i]);
	int err = LUA_OK;
	int msg_base = lua_gettop(L) - argc - argstart - 1;
	lua_pushcfunction(L, msghandler);
	lua_insert(L, msg_base);
	if ( (err = lua_pcall(L, argc - argstart - 1, LUA_MULTRET, msg_base)) != LUA_OK)
	{
		if (err == LUA_ERRRUN)
			fprintf(stderr, "A runtime error when running the script %s has occured\n%s\n", exec_file, lua_tostring(L, -1));
		else if (err == LUA_ERRMEM)
			fprintf(stderr, "A memory allocation error when running the script %s has occured\n%s\n", exec_file, lua_tostring(L, -1));
		else if (err == LUA_ERRERR)
			fprintf(stderr, "A error handling function has errored when running the script %s\n%s\n", exec_file, lua_tostring(L, -1));
		else
			fprintf(stderr, "An unknown error has occured when running the script %s\n%s\n", exec_file, lua_tostring(L, -1));
		lua_close(L);
		return EXIT_FAILURE;
	}
	lua_remove(L, msg_base);


	const char* lbs_cmd = argv[argstart];
	if (argstart >= argc)
		lbs_cmd = "main";
	lua_getglobal(L, lbs_cmd);
	if (lua_isnil(L, -1))
	{
		fprintf(stderr, "Failed to find command %s in buildscript %s to execute\n", lbs_cmd, exec_file);
		lua_close(L);
		return EXIT_FAILURE;
	}
	for (int i = (argstart + 1); i < argc; ++i)
		lua_pushstring(L, argv[i]);

	msg_base = lua_gettop(L) - argc - argstart - 1;
	lua_pushcfunction(L, msghandler);
	lua_insert(L, msg_base);
	if ( (err = lua_pcall(L, argc - argstart - 1, LUA_MULTRET, msg_base)) != LUA_OK)
	{
		if (err == LUA_ERRRUN)
			fprintf(stderr, "A runtime error when running the command %s in the script %s has occured\n%s\n", lbs_cmd, exec_file, lua_tostring(L, -1));
		else if (err == LUA_ERRMEM)
			fprintf(stderr, "A memory allocation error when running the command %s in the script %s has occured\n%s\n", lbs_cmd, exec_file, lua_tostring(L, -1));
		else if (err == LUA_ERRERR)
			fprintf(stderr, "A error handling function has errored when running the command %s in the script %s\n%s\n", lbs_cmd, exec_file, lua_tostring(L, -1));
		else
			fprintf(stderr, "An unknown error has occured when running the command %s in the script %s\n%s\n", lbs_cmd, exec_file, lua_tostring(L, -1));
		lua_close(L);
		return EXIT_FAILURE;
	}
	lua_remove(L, msg_base);

	// If a return value was provided, return it
	if (lua_isnumber(L, -1))
	{
		int rc = lua_tointeger(L, -1);
		lua_close(L);
		return rc;
	}

	// Otherwise return success
	lua_close(L);
	return EXIT_SUCCESS;
}