//go:build linux || darwin

package diagnostics

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

func TestTranscriptStreamDestinations(t *testing.T) {
	fifo := filepath.Join(t.TempDir(), "transcript.pipe")
	if err := syscall.Mkfifo(fifo, 0600); err != nil {
		t.Fatal(err)
	}
	for _, path := range []string{os.DevNull, fifo} {
		t.Run(filepath.Base(path), func(t *testing.T) {
			before, err := os.Stat(path)
			if err != nil {
				t.Fatal(err)
			}
			// Preparation must finish even though the pipe has no reader yet.
			session, err := PrepareOutput(OutputSelection{TranscriptPath: path})
			if err != nil {
				t.Fatal(err)
			}
			var reader *os.File
			if path == fifo {
				// Keep both ends open in the test so publication and reading can be
				// sequential; the small payload fits in the pipe buffer.
				reader, err = os.OpenFile(path, os.O_RDWR|syscall.O_NONBLOCK, 0)
				if err != nil {
					t.Fatal(err)
				}
				defer reader.Close()
			}
			payload := []byte("transcript")
			if failures := session.Finalize(payload, ReportBundle{}, nil); len(failures) != 0 {
				t.Fatal(failures)
			}
			after, err := os.Stat(path)
			if err != nil || !os.SameFile(before, after) || before.Mode() != after.Mode() {
				t.Fatalf("stream replaced: %v", err)
			}
			if reader != nil {
				got := make([]byte, len(payload))
				if _, err := io.ReadFull(reader, got); err != nil || string(got) != string(payload) {
					t.Fatalf("pipe delivery: %q %v", got, err)
				}
			}
		})
	}
}

func TestTranscriptStreamWriteFailure(t *testing.T) {
	if _, err := os.Stat("/dev/full"); os.IsNotExist(err) {
		t.Skip("/dev/full unavailable")
	}
	session, err := PrepareOutput(OutputSelection{TranscriptPath: "/dev/full"})
	if err != nil {
		t.Fatal(err)
	}
	failures := session.Finalize([]byte("transcript"), ReportBundle{}, nil)
	if len(failures) != 1 || failures[0].Kind != "transcript write" {
		t.Fatalf("write failure lost: %+v", failures)
	}
}