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

package lint

import (
	"os"
	"os/exec"
	"path/filepath"
	"strings"
	"testing"

	"sourcedock.dev/petrbalvin/gasm-devkit/arch"
	"sourcedock.dev/petrbalvin/gasm-devkit/parser"
)

// TestGoRuntimeCorpus parses and lints every runtime .s file the local Go
// toolchain ships for all four supported architectures.  This is the
// real-world regression net: it exercises the full breadth of each
// architecture's syntax (macros, addressing modes, branch aliases) against
// production assembly.  It is skipped when the toolchain source is absent.
//
// The bar is zero parse errors and zero error-severity diagnostics; i.e. no
// false "unknown instruction" / "undefined label" findings on code the real
// assembler accepts.  Advisory warnings are reported but not fatal, since they
// are heuristics that may legitimately differ across Go versions.
func TestGoRuntimeCorpus(t *testing.T) {
	out, err := exec.Command("go", "env", "GOROOT").Output()
	if err != nil {
		t.Skipf("cannot locate GOROOT: %v", err)
	}
	dir := filepath.Join(strings.TrimSpace(string(out)), "src", "runtime")
	var files []string
	for _, suffix := range []string{"_amd64.s", "_arm64.s", "_riscv64.s", "_loong64.s"} {
		matches, _ := filepath.Glob(filepath.Join(dir, "*"+suffix))
		files = append(files, matches...)
	}
	if len(files) == 0 {
		t.Skip("Go toolchain source (src/runtime/*.s) not present")
	}

	warnings := 0
	for _, path := range files {
		src, err := os.ReadFile(path)
		if err != nil {
			t.Fatalf("read %s: %v", path, err)
		}
		f, errs := parser.Parse(path, string(src))
		if len(errs) > 0 {
			t.Errorf("parse %s: %v", filepath.Base(path), errs)
			continue
		}
		diags := File(f, Config{Arch: arch.FromFilename(path)})
		for _, d := range diags {
			if d.Severity == Error {
				t.Errorf("%s:%d: error %s: %s", filepath.Base(path), d.Pos.Line, d.Code, d.Message)
			} else {
				warnings++
			}
		}
	}
	if warnings > 0 {
		t.Logf("%d advisory warnings across %d files (non-fatal)", warnings, len(files))
	}
}