package brain_test

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

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

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

func readIndex(t *testing.T, brainDir, wing string) string {
	t.Helper()
	b, _ := os.ReadFile(filepath.Join(brainDir, "wiki", wing, "_index.md"))
	return string(b)
}

// hyperguild#157 slice 5: BuildWingIndex listed wiki/<wing>/<hall>/ with
// os.ReadDir and opened each note by path, so a symlinked note put the
// target's title into _index.md, and a FIFO hung every brain_write.
func TestBuildWingIndexRefusesSymlinkedNotesAndSurvivesSwapRaces(t *testing.T) {
	b := t.TempDir()
	facts := filepath.Join(b, "wiki", "w", "facts")
	require.NoError(t, os.MkdirAll(facts, 0o755))
	require.NoError(t, os.WriteFile(filepath.Join(facts, "ok.md"), []byte("---\ntitle: zqinside\n---\n"), 0o644))
	require.NoError(t, os.Symlink(brainfstest.Outside(t), filepath.Join(facts, "leak.md")))
	inBrain := brainfstest.WriteSentinelAt(t, filepath.Join(b, "raw", "s.md"))
	require.NoError(t, os.Symlink(filepath.Join("..", "..", "..", "raw", "s.md"), filepath.Join(facts, "inlink.md")))

	require.NoError(t, brain.BuildWingIndex(b, "w"))
	idx := readIndex(t, b, "w")
	assert.Contains(t, idx, "zqinside", "positive control")
	assert.NotContains(t, idx, brainfstest.Sentinel)
	assert.NotContains(t, idx, "leak")
	assert.NotContains(t, idx, "inlink")

	p := filepath.Join(facts, "r.md")
	read := func() string {
		_ = brain.BuildWingIndex(b, "w")
		return readIndex(t, b, "w")
	}
	brainfstest.AssertNoLeak(t, p, "---\ntitle: zqinside\n---\n", 1500*time.Millisecond, read)
	brainfstest.AssertNoLeakFrom(t, p, "---\ntitle: zqinside\n---\n", inBrain, 1500*time.Millisecond, read)
	brainfstest.AssertNoHang(t, p, "---\ntitle: zqinside\n---\n", 1500*time.Millisecond, 6*time.Second, func() { _ = read() })
}

// A wing or hall directory that is a symlink is not listed, and nothing is
// written into its target.
func TestBuildWingIndexDoesNotFollowASymlinkedWingOrHall(t *testing.T) {
	b := t.TempDir()
	require.NoError(t, os.MkdirAll(filepath.Join(b, "raw", "facts"), 0o755))
	require.NoError(t, os.WriteFile(filepath.Join(b, "raw", "facts", "r.md"), []byte("---\ntitle: zqrawonly\n---\n"), 0o644))
	require.NoError(t, os.MkdirAll(filepath.Join(b, "wiki", "w"), 0o755))
	require.NoError(t, os.Symlink(filepath.Join("..", "..", "raw", "facts"), filepath.Join(b, "wiki", "w", "facts")))
	require.NoError(t, os.Symlink(filepath.Join("..", "raw"), filepath.Join(b, "wiki", "alias")))

	_ = brain.BuildWingIndex(b, "w")
	assert.NotContains(t, readIndex(t, b, "w"), "zqrawonly", "symlinked hall")

	assert.Error(t, brain.BuildWingIndex(b, "alias"))
	_, err := os.Stat(filepath.Join(b, "raw", "_index.md"))
	assert.True(t, os.IsNotExist(err), "an index was written into the symlinked wing's target")
}

// A link to a symlinked note does not resolve: only regular files count as
// entries, so StripUnresolvedLinks unwraps it.
func TestStripUnresolvedLinksDoesNotCountASymlinkedNoteAsAnEntry(t *testing.T) {
	b := t.TempDir()
	facts := filepath.Join(b, "wiki", "w", "facts")
	require.NoError(t, os.MkdirAll(facts, 0o755))
	require.NoError(t, os.WriteFile(filepath.Join(facts, "real.md"), []byte("x"), 0o644))
	brainfstest.WriteSentinelAt(t, filepath.Join(b, "raw", "s.md"))
	require.NoError(t, os.Symlink(filepath.Join("..", "..", "..", "raw", "s.md"), filepath.Join(facts, "ghost.md")))
	out, unlinked, err := brain.StripUnresolvedLinks(b, "see [[real]] and [[ghost]]")
	require.NoError(t, err)
	assert.Contains(t, out, "[[real]]", "positive control")
	assert.NotContains(t, out, "[[ghost]]")
	assert.Contains(t, unlinked, "ghost")
}