/*
 * 738_module_decl — sentinel for the `package <name>;` keyword.
 *
 * Pins three invariants from the module-system rewrite:
 *   1. The parser ACCEPTS `package foo;` as the first non-comment item.
 *   2. The parser ACCEPTS multiple `package X;` decls (concatenated
 *      multi-file streams from the driver) and stamps subsequent
 *      decls with whichever package is "current".
 *   3. Bare comments + a `package foo;` is still legal — the keyword
 *      may follow leading comments.
 *
 * The relaxed-or-strict missing-package check was softened to a
 * silent default (curmod=NULL) so legacy fragment-driven tests
 * still parse. That softening is documented at parsefile() in
 * cmd/wcc/parse.c.
 */
#include "ww.h"
#include <stdio.h>
#include <string.h>
#include <stdlib.h>

static int
parses_clean(const char *src)
{
	Arena *a = newarena();
	Lex l;
	Parser p;
	lexinit(&l, a, "<test>", src, strlen(src));
	parserinit(&p, a, &l);
	Node *n = parsefile(&p);
	int ok = (n != NULL && p.errs == 0 && l.errs == 0);
	freearena(a);
	return ok;
}

static const char *first_decl_module(Node *file) {
	if (file == NULL || file->list == NULL) return NULL;
	return file->list->module;
}

static int
check_module_stamps(const char *src, const char *want_first, const char *want_last)
{
	Arena *a = newarena();
	Lex l;
	Parser p;
	lexinit(&l, a, "<test>", src, strlen(src));
	parserinit(&p, a, &l);
	Node *n = parsefile(&p);
	int ok = (n != NULL && p.errs == 0 && l.errs == 0);
	if (ok) {
		const char *first = first_decl_module(n);
		Node *last = n->list;
		while (last && last->next) last = last->next;
		const char *lastmod = last ? last->module : NULL;
		int match_first = (first == NULL && want_first == NULL)
		    || (first != NULL && want_first != NULL
		        && strcmp(first, want_first) == 0);
		int match_last = (lastmod == NULL && want_last == NULL)
		    || (lastmod != NULL && want_last != NULL
		        && strcmp(lastmod, want_last) == 0);
		ok = match_first && match_last;
	}
	freearena(a);
	return ok;
}

int
main(void)
{
	int pass = 0, fail = 0;

	/* Row 1: `package foo;` accepted as first non-comment item. */
	if (parses_clean("package foo;\nfn x() void = {};\n")) pass++;
	else { fprintf(stderr, "738[1] basic package accept FAILED\n"); fail++; }

	/* Row 2: comments before `package foo;` legal. */
	if (parses_clean("// header\n// more\npackage foo;\nfn x() void = {};\n")) pass++;
	else { fprintf(stderr, "738[2] package after comments FAILED\n"); fail++; }

	/* Row 3: subsequent decls stamped with current package. */
	if (check_module_stamps(
	    "package foo;\nfn x() void = {};\nfn y() void = {};\n",
	    "foo", "foo")) pass++;
	else { fprintf(stderr, "738[3] decl module stamping FAILED\n"); fail++; }

	/* Row 4: concatenated multi-section stream — second package
	 * decl switches the stamp for subsequent decls. Mirrors driver-
	 * emitted multi-file modules. */
	if (check_module_stamps(
	    "package foo;\nfn a() void = {};\n"
	    "package bar;\nfn b() void = {};\n",
	    "foo", "bar")) pass++;
	else { fprintf(stderr, "738[4] mid-stream package switch FAILED\n"); fail++; }

	/* Row 5: dotted import accepted with leaf stored on N_USE. */
	if (parses_clean(
	    "package foo;\nimport encoding.utf8;\nfn x() void = {};\n")) pass++;
	else { fprintf(stderr, "738[5] dotted import accept FAILED\n"); fail++; }

	/* Row 6: dotted import stores only the leaf identifier on
	 * N_USE.str (post-task-#22 — the driver translates the full
	 * dotted path to a directory walk; the checker only needs the
	 * package bareword for n_use → decl disambiguation). */
	{
		Arena *a = newarena();
		Lex l;
		Parser p;
		const char *src = "package foo;\nimport encoding.utf8;\n";
		lexinit(&l, a, "<test>", src, strlen(src));
		parserinit(&p, a, &l);
		Node *n = parsefile(&p);
		int ok = 0;
		if (n != NULL && p.errs == 0 && l.errs == 0 && n->list != NULL) {
			Node *u = n->list;
			ok = (u->kind == N_USE
			    && u->str != NULL
			    && strcmp(u->str, "utf8") == 0);
		}
		freearena(a);
		if (ok) pass++;
		else { fprintf(stderr, "738[6] dotted import leaf-store FAILED\n"); fail++; }
	}

	printf("738_module_decl: %d pass, %d fail\n", pass, fail);
	return fail == 0 ? 0 : 1;
}