#include <stdlib.h>
#include <string.h>
#include <limits.h>
#include <errno.h>

#include <posthaste/execute.h>
#include <posthaste/parser.h>
#include <posthaste/debug.h>
#include <posthaste/scope.h>
#include <posthaste/check.h>
#include <posthaste/lower.h>
#include <posthaste/core.h>
#include <posthaste/ast.h>

/**
 * Read whole file into a buffer and return pointer to buffer.
 * Possibly kind of silly to have both \p file and \p f.
 * Apparently there's no standardized way to get the file name of a
 * file pointer.
 *
 * @param fname Name of file to read.
 * @param f File pointer.
 * @return Pointer to buffer with file contents.
 */
static char *read_file(const char *fname, FILE *f)
{
	fseek(f, 0, SEEK_END);
	long s = ftell(f);
	if (s == LONG_MAX) {
		/** @todo should probably do this via fstat or something */
		error("%s might be a directory", fname);
		return NULL;
	}

	fseek(f, 0, SEEK_SET);

	char *buf = malloc(s + 1);
	if (!buf)
		return NULL;

	fread(buf, s + 1, 1, f);
	/* remember terminating null */
	buf[s] = 0;
	return buf;
}

int run(const char *fname)
{
	int ret = 0;
	const char *buf = NULL;
	struct scope *scope = NULL;
	struct parser *p = NULL;

	FILE *f = fopen(fname, "rb");
	if (!f) {
		error("failed opening %s: %s\n", fname, strerror(errno));
		return -1;
	}

	buf = read_file(fname, f);
	fclose(f);

	if (!buf) {
		ret = -1;
		goto out;
	}

	p = create_parser();
	if (!p) {
		ret = -1;
		goto out;
	}

	parse(p, fname, buf);
	if (p->failed) {
		ret = -1;
		goto out;
	}

	scope = create_scope();
	if (!scope) {
		ret = -1;
		goto out;
	}

	scope_set_file(scope, fname, buf);

	struct ast *ast = p->tree;
	if (check(scope, ast)) {
		ret = -1;
		goto out;
	}

	if (lower_ast(ast)) {
		ret = -1;
		goto out;
	}

	execute();

out:
	free((void *)buf);
	destroy_lowering();
	destroy_scopes();
	destroy_ast_nodes();
	destroy_parser(p);
	return ret;
}