package notes

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

	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"

	"github.com/mathiasbq/hyperguild/ingestion/internal/brainfs/brainfstest"
)

// hyperguild#157 slice 2: ReadScoped (brain_read) Lstat-checked the final
// component, then reopened by name with os.ReadFile: a swap after the check
// was followed, and a FIFO blocked the read. It now reads through brainfs.
func TestReadScopedRefusesSymlinksAndSurvivesSwapRaces(t *testing.T) {
	brain := t.TempDir()
	facts := filepath.Join(brain, "wiki", "w", "facts")
	require.NoError(t, os.MkdirAll(facts, 0o755))
	p := filepath.Join(facts, "r.md")
	read := func() string {
		b, _ := ReadScoped(brain, "wiki/w/facts/r.md", ScopeNotes)
		return string(b)
	}
	require.NoError(t, os.WriteFile(p, []byte("inside"), 0o644))
	assert.Equal(t, "inside", read())
	brainfstest.AssertNoLeak(t, p, "inside", 1500*time.Millisecond, read)
	brainfstest.AssertNoHang(t, p, "inside", 1500*time.Millisecond, 6*time.Second, func() { _ = read() })
}

func TestReadScopedRefusesANoteOverMaxNoteBytes(t *testing.T) {
	brain := t.TempDir()
	facts := filepath.Join(brain, "wiki", "w", "facts")
	require.NoError(t, os.MkdirAll(facts, 0o755))
	require.NoError(t, os.WriteFile(filepath.Join(facts, "big.md"), make([]byte, maxNoteBytes+1), 0o644))
	_, err := ReadScoped(brain, "wiki/w/facts/big.md", ScopeNotes)
	assert.ErrorIs(t, err, ErrTooLarge)
}

// hyperguild#171 (review of #172, finding 1): os.Root alone refuses links that
// leave the brain, so the outside-target race above stays green for a reader
// that skips brainfs's Lstat and SameFile checks. An in-brain target (raw/,
// outside ScopeNotes) is what tells them apart.
func TestReadScopedDoesNotReturnAnInBrainSymlinkTargetStaticallyOrDuringASampledSwapRace(t *testing.T) {
	brain := t.TempDir()
	facts := filepath.Join(brain, "wiki", "w", "facts")
	require.NoError(t, os.MkdirAll(facts, 0o755))
	target := brainfstest.WriteSentinelAt(t, filepath.Join(brain, "raw", "s.md"))

	require.NoError(t, os.Symlink(filepath.Join("..", "..", "..", "raw", "s.md"), filepath.Join(facts, "inlink.md")))
	b, err := ReadScoped(brain, "wiki/w/facts/inlink.md", ScopeNotes)
	assert.Error(t, err, "static in-brain link")
	assert.NotContains(t, string(b), brainfstest.Sentinel, "static in-brain link")

	p := filepath.Join(facts, "r.md")
	require.NoError(t, os.WriteFile(p, []byte("inside"), 0o644))
	b, err = ReadScoped(brain, "wiki/w/facts/r.md", ScopeNotes)
	require.NoError(t, err)
	assert.Equal(t, "inside", string(b), "positive control: a regular note reads")

	read := func() string {
		b, _ := ReadScoped(brain, "wiki/w/facts/r.md", ScopeNotes)
		return string(b)
	}
	brainfstest.AssertNoLeakFrom(t, p, "inside", target, 1500*time.Millisecond, read)
}