package benchmarks

import (
	"context"
	"fmt"
	"path/filepath"
	"testing"
	"time"

	"github.com/alicebob/miniredis/v2"
	"github.com/jfraeys/fetch_ml/internal/metrics"
	"github.com/jfraeys/fetch_ml/internal/storage"
	fixtures "github.com/jfraeys/fetch_ml/tests/fixtures"
	"github.com/redis/go-redis/v9"
)

// BenchmarkMLExperimentExecution measures ML experiment performance
func BenchmarkMLExperimentExecution(b *testing.B) {
	// Setup test environment
	tempDir := b.TempDir()
	rdb := setupBenchmarkRedis(b)
	if rdb == nil {
		b.Skip("Redis not available")
	}
	defer func() { _ = rdb.Close() }()

	db, err := storage.NewDBFromPath(filepath.Join(tempDir, "test.db"))
	if err != nil {
		b.Fatalf("Failed to create database: %v", err)
	}
	defer func() { _ = db.Close() }()

	// Initialize database schema
	err = db.Initialize(getMLSchema())
	if err != nil {
		b.Fatalf("Failed to initialize database: %v", err)
	}

	b.ResetTimer()
	b.ReportAllocs()

	// Benchmark different experiment types
	b.Run("SmallExperiment", func(b *testing.B) {
		benchmarkMLExperiment(b, db, rdb, "small", 100, 1024) // 100 jobs, 1KB each
	})

	b.Run("MediumExperiment", func(b *testing.B) {
		benchmarkMLExperiment(b, db, rdb, "medium", 50, 10240) // 50 jobs, 10KB each
	})

	b.Run("LargeExperiment", func(b *testing.B) {
		benchmarkMLExperiment(b, db, rdb, "large", 10, 102400) // 10 jobs, 100KB each
	})

	b.Run("ConcurrentExperiments", func(b *testing.B) {
		benchmarkConcurrentExperiments(b, db, rdb)
	})

	b.Run("ExperimentMetrics", func(b *testing.B) {
		benchmarkExperimentMetrics(b, db, rdb)
	})
}

// benchmarkMLExperiment tests ML experiment execution performance
func benchmarkMLExperiment(b *testing.B, db *storage.DB, rdb *redis.Client, expType string, numJobs, payloadSize int) {
	m := &metrics.Metrics{}

	for i := 0; i < b.N; i++ {
		expID := fmt.Sprintf("exp-%s-%d-%d", expType, i, time.Now().UnixNano())

		// Create experiment
		start := time.Now()
		err := createMLExperiment(db, rdb, expID, numJobs, payloadSize)
		if err != nil {
			b.Fatalf("Failed to create experiment: %v", err)
		}
		m.RecordTaskStart()

		// Simulate experiment execution
		err = executeMLExperiment(db, rdb, expID, numJobs)
		if err != nil {
			b.Fatalf("Failed to execute experiment: %v", err)
		}
		m.RecordTaskCompletion()

		executionTime := time.Since(start)
		m.RecordDataTransfer(int64(numJobs*payloadSize), 0)
		_ = executionTime // Use executionTime to avoid unused variable warning

		// Record experiment metrics
		for j := range 5 {
			metricName := fmt.Sprintf("metric_%d_%d", j, i)
			err := db.RecordJobMetric(expID, metricName, fmt.Sprintf("%.2f", float64(j)*1.5))
			if err != nil {
				b.Errorf("Failed to record metric %s: %v", metricName, err)
			}
		}
	}
}

// benchmarkConcurrentExperiments tests concurrent experiment execution
func benchmarkConcurrentExperiments(b *testing.B, db *storage.DB, rdb *redis.Client) {
	numExperiments := 5
	jobsPerExperiment := 20
	payloadSize := 5120 // 5KB

	b.ResetTimer()

	// Create experiments concurrently
	for i := 0; b.Loop(); i++ {
		done := make(chan bool, numExperiments)

		for exp := range numExperiments {
			go func(expID int) {
				defer func() { done <- true }()

				expName := fmt.Sprintf("concurrent-exp-%d-%d-%d", i, expID, time.Now().UnixNano())
				err := createMLExperiment(db, rdb, expName, jobsPerExperiment, payloadSize)
				if err != nil {
					b.Errorf("Failed to create experiment %d: %v", expID, err)
					return
				}

				err = executeMLExperiment(db, rdb, expName, jobsPerExperiment)
				if err != nil {
					b.Errorf("Failed to execute experiment %d: %v", expID, err)
				}
			}(exp)
		}

		// Wait for all experiments to complete
		for j := 0; j < numExperiments; j++ {
			<-done
		}
	}
}

// benchmarkExperimentMetrics tests metrics recording performance
func benchmarkExperimentMetrics(b *testing.B, db *storage.DB, _ *redis.Client) {
	metricsPerJob := 10
	numJobs := 100

	// Create test jobs
	jobIDs := make([]string, numJobs)
	for i := range jobIDs {
		jobIDs[i] = fmt.Sprintf("metrics-job-%d-%d", i, time.Now().UnixNano())

		job := &storage.Job{
			ID:       jobIDs[i],
			JobName:  fmt.Sprintf("Metrics Job %d", i),
			Status:   "completed",
			Priority: 0,
		}

		err := db.CreateJob(job)
		if err != nil {
			b.Fatalf("Failed to create job %d: %v", i, err)
		}
	}

	b.ResetTimer()
	b.ReportAllocs()

	// Record metrics for all jobs
	for i := 0; b.Loop(); i++ {
		for _, jobID := range jobIDs {
			for j := range metricsPerJob {
				metricName := fmt.Sprintf("metric_%d_%d", j, i)
				metricValue := fmt.Sprintf("%.6f", float64(i*j)*0.001)

				err := db.RecordJobMetric(jobID, metricName, metricValue)
				if err != nil {
					b.Errorf("Failed to record metric %s for job %s: %v", metricName, jobID, err)
				}
			}
		}
	}
}

// BenchmarkDatasetOperations tests dataset-related performance
func BenchmarkDatasetOperations(b *testing.B) {
	tempDir := b.TempDir()
	db, err := storage.NewDBFromPath(filepath.Join(tempDir, "test.db"))
	if err != nil {
		b.Fatalf("Failed to create database: %v", err)
	}
	defer func() { _ = db.Close() }()

	err = db.Initialize(getMLSchema())
	if err != nil {
		b.Fatalf("Failed to initialize database: %v", err)
	}

	b.ResetTimer()
	b.ReportAllocs()

	b.Run("DatasetCreation", func(b *testing.B) {
		benchmarkDatasetCreation(b, db)
	})

	b.Run("DatasetRetrieval", func(b *testing.B) {
		benchmarkDatasetRetrieval(b, db)
	})

	b.Run("DatasetUpdate", func(b *testing.B) {
		benchmarkDatasetUpdate(b, db)
	})
}

func benchmarkDatasetCreation(b *testing.B, db *storage.DB) {
	for i := 0; b.Loop(); i++ {
		datasetID := fmt.Sprintf("dataset-%d-%d", i, time.Now().UnixNano())

		// Create a job first for foreign key constraint
		job := &storage.Job{
			ID:       datasetID,
			JobName:  fmt.Sprintf("Dataset %d", i),
			Status:   "completed",
			Priority: 0,
		}
		err := db.CreateJob(job)
		if err != nil {
			b.Errorf("Failed to create dataset job %d: %v", i, err)
			continue
		}

		// Simulate dataset creation with metadata
		err = db.RecordJobMetric(datasetID, "dataset_size", fmt.Sprintf("%d", 1024*(i+1)))
		if err != nil {
			b.Errorf("Failed to create dataset %d: %v", i, err)
		}

		err = db.RecordJobMetric(datasetID, "dataset_type", "training")
		if err != nil {
			b.Errorf("Failed to set dataset type %d: %v", i, err)
		}

		err = db.RecordJobMetric(datasetID, "created_at", time.Now().Format(time.RFC3339))
		if err != nil {
			b.Errorf("Failed to set dataset timestamp %d: %v", i, err)
		}
	}
}

func benchmarkDatasetRetrieval(b *testing.B, db *storage.DB) {
	// Pre-create datasets
	numDatasets := 100
	for i := range numDatasets {
		datasetID := fmt.Sprintf("dataset-%d-%d", i, time.Now().UnixNano())

		// Create a job first
		job := &storage.Job{
			ID:       datasetID,
			JobName:  fmt.Sprintf("Dataset %d", i),
			Status:   "completed",
			Priority: 0,
		}
		_ = db.CreateJob(job)

		_ = db.RecordJobMetric(datasetID, "dataset_size", fmt.Sprintf("%d", 1024*(i+1)))
		_ = db.RecordJobMetric(datasetID, "dataset_type", "training")
	}

	for i := 0; b.Loop(); i++ {
		datasetID := fmt.Sprintf("dataset-%d", i%numDatasets)

		// Simulate dataset metadata retrieval
		// In a real implementation, this would query the database
		// For benchmarking, we'll simulate the lookup cost
		_ = datasetID
	}
}

func benchmarkDatasetUpdate(b *testing.B, db *storage.DB) {
	// Pre-create datasets
	numDatasets := 50
	datasetIDs := make([]string, numDatasets)
	for i := range numDatasets {
		datasetID := fmt.Sprintf("dataset-%d-%d", i, time.Now().UnixNano())
		datasetIDs[i] = datasetID

		// Create a job first
		job := &storage.Job{
			ID:       datasetID,
			JobName:  fmt.Sprintf("Dataset %d", i),
			Status:   "completed",
			Priority: 0,
		}
		_ = db.CreateJob(job)

		_ = db.RecordJobMetric(datasetID, "dataset_size", fmt.Sprintf("%d", 1024))
	}

	for i := 0; b.Loop(); i++ {
		datasetID := datasetIDs[i%numDatasets]

		// Update dataset metadata
		err := db.RecordJobMetric(datasetID, fmt.Sprintf("dataset_size_%d", i), fmt.Sprintf("%d", 2048))
		if err != nil {
			b.Errorf("Failed to update dataset %d: %v", i, err)
		}

		err = db.RecordJobMetric(datasetID, fmt.Sprintf("last_modified_%d", i), time.Now().Format(time.RFC3339))
		if err != nil {
			b.Errorf("Failed to update timestamp %d: %v", i, err)
		}
	}
}

// Helper functions

func setupBenchmarkRedis(b *testing.B) *redis.Client {
	// Start in-memory Redis server
	s, err := miniredis.Run()
	if err != nil {
		b.Fatalf("failed to start miniredis: %v", err)
	}

	rdb := redis.NewClient(&redis.Options{
		Addr: s.Addr(),
	})

	ctx := context.Background()
	if err := rdb.Ping(ctx).Err(); err != nil {
		b.Fatalf("miniredis ping failed: %v", err)
	}

	b.Cleanup(func() {
		rdb.Close()
		s.Close()
	})

	return rdb
}

func createMLExperiment(db *storage.DB, rdb *redis.Client, expID string, numJobs, payloadSize int) error {
	ctx := context.Background()

	// Create experiment metadata
	expJob := &storage.Job{
		ID:       expID,
		JobName:  fmt.Sprintf("ML Experiment %s", expID),
		Status:   "running",
		Priority: 1,
		Args:     fmt.Sprintf(`{"experiment_id": "%s", "num_jobs": %d}`, expID, numJobs),
	}

	err := db.CreateJob(expJob)
	if err != nil {
		return fmt.Errorf("failed to create experiment job: %w", err)
	}

	// Create individual jobs for the experiment
	for i := range numJobs {
		jobID := fmt.Sprintf("%s-job-%d", expID, i)

		payload := generateMLPayload(payloadSize, i)

		job := &storage.Job{
			ID:       jobID,
			JobName:  fmt.Sprintf("ML Job %s-%d", expID, i),
			Status:   "pending",
			Priority: 1,
			Args:     payload,
		}

		err = db.CreateJob(job)
		if err != nil {
			return fmt.Errorf("failed to create job %d: %w", i, err)
		}

		// Queue job in Redis
		err = rdb.LPush(ctx, "ml:queue", jobID).Err()
		if err != nil {
			return fmt.Errorf("failed to queue job %d: %w", i, err)
		}
	}

	return nil
}

func executeMLExperiment(db *storage.DB, rdb *redis.Client, expID string, numJobs int) error {
	ctx := context.Background()

	// Process all jobs in the experiment
	for i := range numJobs {
		jobID := fmt.Sprintf("%s-job-%d", expID, i)

		// Update job status to running
		err := db.UpdateJobStatus(jobID, "running", fmt.Sprintf("worker-%d", i%5), "")
		if err != nil {
			return fmt.Errorf("failed to start job %d: %w", i, err)
		}

		// Simulate processing time (in real scenario, this would be ML computation)
		time.Sleep(time.Microsecond * time.Duration(10+i%100))

		// Update job status to completed
		err = db.UpdateJobStatus(jobID, "completed", fmt.Sprintf("worker-%d", i%5), "")
		if err != nil {
			return fmt.Errorf("failed to complete job %d: %w", i, err)
		}

		// Record job metrics
		err = db.RecordJobMetric(jobID, "processing_time", fmt.Sprintf("%.3f", float64(10+i%100)*0.001))
		if err != nil {
			return fmt.Errorf("failed to record processing time for job %d: %w", i, err)
		}

		err = db.RecordJobMetric(jobID, "memory_usage", fmt.Sprintf("%d", 1024*(i+1)))
		if err != nil {
			return fmt.Errorf("failed to record memory usage for job %d: %w", i, err)
		}

		// Pop from queue
		_, err = rdb.LPop(ctx, "ml:queue").Result()
		if err != nil {
			return fmt.Errorf("failed to pop job %d: %w", i, err)
		}
	}

	// Update experiment status
	err := db.UpdateJobStatus(expID, "completed", "coordinator", "")
	if err != nil {
		return fmt.Errorf("failed to complete experiment: %w", err)
	}

	return nil
}

func generateMLPayload(size int, seed int) string {
	data := make([]byte, size)
	for i := range data {
		data[i] = byte((i + seed) % 256)
	}

	return fmt.Sprintf(`{
		"model": "test-model",
		"data": "%s",
		"parameters": {
			"learning_rate": 0.001,
			"batch_size": 32,
			"epochs": 10
		},
		"seed": %d
	}`, string(data[:minInt(len(data), 100)]), seed) // Truncate data for JSON safety
}

func getMLSchema() string {
	return fixtures.TestSchema
}

func minInt(a, b int) int {
	if a < b {
		return a
	}
	return b
}