/*
 * Copyright (C) 2021 Jo-Philipp Wich <jo@mein.io>
 *
 * Permission to use, copy, modify, and/or distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include <stdio.h>

#include <ucode/compiler.h>
#include <ucode/lib.h>
#include <ucode/vm.h>


#define MULTILINE_STRING(...) #__VA_ARGS__

static const char *program = MULTILINE_STRING(
	{%
		print("add() = " + add(5, 3.1, 2) + "\n");
		print("multiply() = " + multiply(7.3, 5) + "\n");
	%}
);

static uc_parse_config_t config = {
	.strict_declarations = false,
	.lstrip_blocks = true,
	.trim_blocks = true
};

static uc_value_t *
multiply_two_numbers(uc_vm_t *vm, size_t nargs)
{
	uc_value_t *x = uc_fn_arg(0);
	uc_value_t *y = uc_fn_arg(1);

	return ucv_double_new(ucv_to_double(x) * ucv_to_double(y));
}

static uc_value_t *
add_all_numbers(uc_vm_t *vm, size_t nargs)
{
	double res = 0.0;

	for (size_t n = 0; n < nargs; n++)
		res += ucv_to_double(uc_fn_arg(n));

	return ucv_double_new(res);
}

int main(int argc, char **argv)
{
	int exit_code = 0;

	/* create a source buffer containing the program code */
	uc_source_t *src = uc_source_new_buffer("my program", strdup(program), strlen(program));

	/* compile source buffer into function */
	char *syntax_error = NULL;
	uc_function_t *progfunc = uc_compile(&config, src, &syntax_error);

	/* release source buffer */
	uc_source_put(src);

	/* check if compilation failed */
	if (!progfunc) {
		fprintf(stderr, "Failed to compile program: %s\n", syntax_error);

		return 1;
	}

	/* initialize VM context */
	uc_vm_t vm = { 0 };
	uc_vm_init(&vm, &config);

	/* load standard library into global VM scope */
	uc_stdlib_load(uc_vm_scope_get(&vm));

	/* register our native functions as "add" and "multiply" */
	uc_function_register(uc_vm_scope_get(&vm), "add", add_all_numbers);
	uc_function_register(uc_vm_scope_get(&vm), "multiply", multiply_two_numbers);

	/* execute program function */
	int return_code = uc_vm_execute(&vm, progfunc, NULL);

	/* handle return status */
	if (return_code == ERROR_COMPILE || return_code == ERROR_RUNTIME) {
		printf("An error occurred while running the program\n");
		exit_code = 1;
	}

	/* free VM context */
	uc_vm_free(&vm);

	return exit_code;
}
