package agate

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

func TestSnapshotAsync(t *testing.T) {
	// Setup temporary work directory
	workDir, err := os.MkdirTemp("", "agate_async_test")
	if err != nil {
		t.Fatal(err)
	}
	defer os.RemoveAll(workDir)

	// Initialize Agate
	opts := AgateOptions{
		WorkDir: workDir,
		Logger:  nil, // Disable logging for test
	}

	ag, err := New(opts)
	if err != nil {
		t.Fatalf("Failed to initialize Agate: %v", err)
	}
	defer ag.Close()

	// Get active directory and create some dummy files
	activeDir := ag.GetActiveDir()
	if err := os.MkdirAll(activeDir, 0755); err != nil {
		t.Fatalf("Failed to create active dir: %v", err)
	}

	// Create a large-ish file to ensure it takes some time (though still fast)
	dummyFile := filepath.Join(activeDir, "data.bin")
	data := make([]byte, 1024*1024) // 1MB
	if err := os.WriteFile(dummyFile, data, 0644); err != nil {
		t.Fatalf("Failed to create dummy file: %v", err)
	}

	// Start async snapshot
	ctx := context.Background()
	snapshotID, err := ag.SnapshotAsync(ctx, "async-snap", "")
	if err != nil {
		t.Fatalf("SnapshotAsync failed: %v", err)
	}

	if snapshotID == "" {
		t.Fatal("SnapshotAsync returned empty ID")
	}

	// Check status immediately
	status, err := ag.GetSnapshotStatus(ctx, snapshotID)
	if err != nil {
		t.Fatalf("GetSnapshotStatus failed: %v", err)
	}

	// Status should be pending or running
	if status.Status != "pending" && status.Status != "running" {
		t.Errorf("Initial status should be pending or running, got: %s", status.Status)
	}

	// Poll for completion
	timeout := time.After(5 * time.Second)
	ticker := time.NewTicker(10 * time.Millisecond)
	defer ticker.Stop()

	done := false
	for !done {
		select {
		case <-timeout:
			t.Fatal("Timeout waiting for snapshot completion")
		case <-ticker.C:
			status, err := ag.GetSnapshotStatus(ctx, snapshotID)
			if err != nil {
				t.Fatalf("GetSnapshotStatus failed during polling: %v", err)
			}

			if status.Status == "done" {
				done = true
				if status.Progress != 1.0 {
					t.Errorf("Expected progress 1.0, got %f", status.Progress)
				}
			} else if status.Status == "failed" {
				t.Fatalf("Snapshot creation failed: %s", status.Error)
			}
		}
	}

	// Verify snapshot exists
	snaps, err := ag.ListSnapshots(ctx)
	if err != nil {
		t.Fatalf("ListSnapshots failed: %v", err)
	}

	found := false
	for _, s := range snaps {
		if s.ID == snapshotID {
			found = true
			break
		}
	}

	if !found {
		t.Errorf("Snapshot %s not found in list", snapshotID)
	}

	// Verify current snapshot ID is updated
	if ag.GetCurrentSnapshotID() != snapshotID {
		t.Errorf("Current snapshot ID not updated. Expected %s, got %s", snapshotID, ag.GetCurrentSnapshotID())
	}
}