package claudewatcher

import (
	"context"
	"os"
	"path/filepath"
	"strings"
	"sync"
	"testing"
	"time"

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

// memSink captures batches without touching postgres. Thread-safe so
// TickOnce can run from any goroutine in concurrent tests.
type memSink struct {
	mu      sync.Mutex
	batches []Batch
	failOn  string // file basename to error on
}

func (m *memSink) Ingest(_ context.Context, b Batch) error {
	m.mu.Lock()
	defer m.mu.Unlock()
	if m.failOn != "" && strings.Contains(b.FilePath, m.failOn) {
		return assert.AnError
	}
	m.batches = append(m.batches, b)
	return nil
}

func writeSession(t *testing.T, dir, sessionID string, lines []string) string {
	t.Helper()
	path := filepath.Join(dir, sessionID+".jsonl")
	body := strings.Join(lines, "\n") + "\n"
	require.NoError(t, os.WriteFile(path, []byte(body), 0o644))
	return path
}

func TestTickOnce_NoCursorReingestsEverythingEveryTick(t *testing.T) {
	tmp := t.TempDir()
	projectDir := filepath.Join(tmp, "-home-mathias-dev")
	require.NoError(t, os.MkdirAll(projectDir, 0o755))
	writeSession(t, projectDir, "sess1", []string{
		`{"type":"user","sessionId":"sess1","message":"first prompt"}`,
		`{"type":"assistant","sessionId":"sess1","message":{"content":[{"type":"text","text":"first answer"}]}}`,
	})

	sink := &memSink{}
	cfg := Config{
		SessionsDir: tmp,
		Host:        "koala",
		Sink:        sink,
	}
	require.NoError(t, TickOnce(context.Background(), cfg))
	require.NoError(t, TickOnce(context.Background(), cfg))

	require.Len(t, sink.batches, 2, "no cursor => re-emits same batch every tick")
	assert.Equal(t, "sess1", sink.batches[0].SessionID)
	assert.Equal(t, "koala", sink.batches[0].Host)
	assert.Equal(t, "-home-mathias-dev", sink.batches[0].ProjectID)
	assert.Len(t, sink.batches[0].Turns, 2)
}

func TestTickOnce_FiltersSkipTurnsAndScrubberMatches(t *testing.T) {
	tmp := t.TempDir()
	proj := filepath.Join(tmp, "-home-mathias-dev")
	require.NoError(t, os.MkdirAll(proj, 0o755))
	writeSession(t, proj, "sess-scrub", []string{
		`{"type":"queue-operation","sessionId":"sess-scrub","content":"x"}`, // Skip
		`{"type":"user","sessionId":"sess-scrub","message":"normal prompt"}`,
		`{"type":"assistant","sessionId":"sess-scrub","message":{"content":[{"type":"text","text":"value POSTGRES_PASSWORD=hunter2supersecretvalue"}]}}`, // scrubbed
	})
	sink := &memSink{}
	require.NoError(t, TickOnce(context.Background(), Config{
		SessionsDir: tmp, Host: "koala", Sink: sink,
	}))
	require.Len(t, sink.batches, 1)
	turns := sink.batches[0].Turns
	require.Len(t, turns, 1, "skip + scrubbed turns must not reach the sink")
	assert.Equal(t, "user", turns[0].Type)
}

func TestTickOnce_AllScrubbedNoBatchEmitted(t *testing.T) {
	tmp := t.TempDir()
	proj := filepath.Join(tmp, "-home-mathias-dev")
	require.NoError(t, os.MkdirAll(proj, 0o755))
	writeSession(t, proj, "all-bad", []string{
		`{"type":"user","sessionId":"all-bad","message":"Authorization: Bearer abcdef1234567890ghijklmnop"}`,
	})
	sink := &memSink{}
	require.NoError(t, TickOnce(context.Background(), Config{
		SessionsDir: tmp, Host: "koala", Sink: sink,
	}))
	assert.Empty(t, sink.batches, "no usable turns => no batch")
}

func TestTickOnce_IgnoresNonJsonlFiles(t *testing.T) {
	tmp := t.TempDir()
	proj := filepath.Join(tmp, "-home-mathias-dev")
	require.NoError(t, os.MkdirAll(proj, 0o755))
	require.NoError(t, os.WriteFile(filepath.Join(proj, "README.md"), []byte("ignore me"), 0o644))
	require.NoError(t, os.WriteFile(filepath.Join(proj, "config.json"), []byte("{}"), 0o644))
	sink := &memSink{}
	require.NoError(t, TickOnce(context.Background(), Config{
		SessionsDir: tmp, Host: "koala", Sink: sink,
	}))
	assert.Empty(t, sink.batches)
}

func TestTickOnce_HandlesMultipleProjectsAndSessions(t *testing.T) {
	tmp := t.TempDir()
	projA := filepath.Join(tmp, "-home-mathias-dev")
	projB := filepath.Join(tmp, "-home-mathias-AI-infra")
	require.NoError(t, os.MkdirAll(projA, 0o755))
	require.NoError(t, os.MkdirAll(projB, 0o755))
	writeSession(t, projA, "a1", []string{`{"type":"user","sessionId":"a1","message":"q1"}`})
	writeSession(t, projA, "a2", []string{`{"type":"user","sessionId":"a2","message":"q2"}`})
	writeSession(t, projB, "b1", []string{`{"type":"user","sessionId":"b1","message":"q3"}`})

	sink := &memSink{}
	require.NoError(t, TickOnce(context.Background(), Config{
		SessionsDir: tmp, Host: "koala", Sink: sink,
	}))
	require.Len(t, sink.batches, 3)

	projects := map[string]int{}
	for _, b := range sink.batches {
		projects[b.ProjectID]++
	}
	assert.Equal(t, 2, projects["-home-mathias-dev"])
	assert.Equal(t, 1, projects["-home-mathias-AI-infra"])
}

func TestTickOnce_SinkErrorDoesNotKillOtherFiles(t *testing.T) {
	tmp := t.TempDir()
	proj := filepath.Join(tmp, "-home-mathias-dev")
	require.NoError(t, os.MkdirAll(proj, 0o755))
	writeSession(t, proj, "good", []string{`{"type":"user","sessionId":"good","message":"q"}`})
	writeSession(t, proj, "bad-session", []string{`{"type":"user","sessionId":"bad-session","message":"q"}`})

	sink := &memSink{failOn: "bad-session"}
	require.NoError(t, TickOnce(context.Background(), Config{
		SessionsDir: tmp, Host: "koala", Sink: sink,
	}))
	require.Len(t, sink.batches, 1, "good session still ingested")
	assert.Equal(t, "good", sink.batches[0].SessionID)
}

func TestWatch_RespectsContextCancel(t *testing.T) {
	tmp := t.TempDir()
	require.NoError(t, os.MkdirAll(filepath.Join(tmp, "-home-mathias-dev"), 0o755))
	sink := &memSink{}
	ctx, cancel := context.WithCancel(context.Background())
	done := make(chan error, 1)
	go func() {
		done <- Watch(ctx, Config{
			SessionsDir: tmp,
			Host:        "koala",
			Interval:    10 * time.Millisecond,
			Sink:        sink,
		})
	}()
	time.Sleep(50 * time.Millisecond)
	cancel()
	select {
	case err := <-done:
		assert.ErrorIs(t, err, context.Canceled)
	case <-time.After(2 * time.Second):
		t.Fatal("Watch did not return after cancel")
	}
}