// Copyright (c) 2026 Petr Balvín <opensource@petrbalvin.org> (https://petrbalvin.org)
// SPDX-License-Identifier: BSD-3-Clause

package parser

import (
	"os"
	"path/filepath"
	"testing"
)

// FuzzParse hammers the parser with arbitrary input.  The contract: no panic,
// and always a usable file, whether or not diagnostics were reported.  The
// seed corpus carries the repository's kernels, so a plain `go test` run
// replays every seed as a regression case and CI exercises them without any
// fuzzing budget.
func FuzzParse(f *testing.F) {
	for _, pattern := range []string{
		"../testdata/*.s",
		"../testdata/verify/*.s",
	} {
		files, _ := filepath.Glob(pattern)
		for _, path := range files {
			if b, err := os.ReadFile(path); err == nil {
				f.Add(string(b))
			}
		}
	}
	f.Add("TEXT ·f(SB), NOSPLIT, $0\n\tRET\n")
	f.Add("garbage ### ??? ::: \xff\xfe\n")
	f.Add("#define A(x) x+1\nTEXT ·f(SB), $0\n\tA(2)\n\tRET\n")
	f.Add("DATA t<>+0(SB)/8, $1\nGLOBL t<>(SB), RODATA, $8\n")
	f.Add("TEXT ·f(SB), $0\n\tJMP (AX)\n\tCALL (BX)\n\tRET\n")

	f.Fuzz(func(t *testing.T, src string) {
		file, _ := Parse("fuzz.s", src)
		if file == nil {
			t.Fatal("Parse returned a nil file")
		}
	})
}