package tests

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

	tests "github.com/jfraeys/fetch_ml/tests/fixtures"
)

const (
	statusRunning   = "running"
	statusCompleted = "completed"
)

// TestIntegrationE2E tests the complete end-to-end workflow
func TestIntegrationE2E(t *testing.T) {
	t.Parallel() // Enable parallel execution

	testDir := t.TempDir()
	ctx := context.Background()

	// Create test job directory structure
	jobBaseDir := filepath.Join(testDir, "jobs")
	pendingDir := filepath.Join(jobBaseDir, "pending")
	runningDir := filepath.Join(jobBaseDir, "running")
	finishedDir := filepath.Join(jobBaseDir, "finished")

	for _, dir := range []string{pendingDir, runningDir, finishedDir} {
		if err := os.MkdirAll(dir, 0750); err != nil {
			t.Fatalf("Failed to create directory %s: %v", dir, err)
		}
	}

	// Create standard ML experiment (zero-install style)
	jobDir := filepath.Join(pendingDir, "test_job")
	if err := os.MkdirAll(jobDir, 0750); err != nil {
		t.Fatalf("Failed to create job directory: %v", err)
	}

	// Create standard ML project files
	trainScript := filepath.Join(jobDir, "train.py")
	requirementsFile := filepath.Join(jobDir, "requirements.txt")
	readmeFile := filepath.Join(jobDir, "README.md")

	// Create train.py (standard ML script)
	trainCode := `#!/usr/bin/env python3
import argparse
import json
import logging
import time
from pathlib import Path

def main():
    parser = argparse.ArgumentParser(description="Train ML model")
    parser.add_argument("--epochs", type=int, default=10, help="Number of epochs")
    parser.add_argument("--lr", type=float, default=0.001, help="Learning rate")
    parser.add_argument("--batch_size", type=int, default=32, help="Batch size")
    parser.add_argument("--output_dir", type=str, required=True, help="Output directory")
    parser.add_argument("--data_dir", type=str, help="Data directory")
    parser.add_argument("--datasets", type=str, help="Comma-separated datasets")
    
    args = parser.parse_args()
    
    # Setup logging
    logging.basicConfig(level=logging.INFO, format='%(asctime)s - %(levelname)s - %(message)s')
    logger = logging.getLogger(__name__)
    
    # Create output directory
    output_dir = Path(args.output_dir)
    output_dir.mkdir(parents=True, exist_ok=True)
    
    logger.info(f"Starting training: {args.epochs} epochs, lr={args.lr}, batch_size={args.batch_size}")
    
    if args.datasets:
        logger.info(f"Using datasets: {args.datasets}")
    
    # Simulate training
    for epoch in range(args.epochs):
        loss = 1.0 - (epoch * 0.08)
        accuracy = 0.4 + (epoch * 0.055)
        
        logger.info(f"Epoch {epoch + 1}/{args.epochs}: loss={loss:.4f}, accuracy={accuracy:.4f}")
        time.sleep(0.01)  # Minimal delay for testing
    
    # Save results
    results = {
        "model_type": "test_model",
        "epochs_trained": args.epochs,
        "learning_rate": args.lr,
        "batch_size": args.batch_size,
        "final_accuracy": accuracy,
        "final_loss": loss,
        "datasets": args.datasets.split(",") if args.datasets else []
    }
    
    results_file = output_dir / "results.json"
    with open(results_file, 'w') as f:
        json.dump(results, f, indent=2)
    
    logger.info(f"Training completed! Results saved to {results_file}")

if __name__ == "__main__":
    main()
`

	//nolint:gosec // G306: Script needs execute permissions
	if err := os.WriteFile(trainScript, []byte(trainCode), 0750); err != nil {
		t.Fatalf("Failed to create train.py: %v", err)
	}

	// Create requirements.txt
	requirements := `torch>=1.9.0
numpy>=1.21.0
scikit-learn>=1.0.0
`

	if err := os.WriteFile(requirementsFile, []byte(requirements), 0600); err != nil {
		t.Fatalf("Failed to create requirements.txt: %v", err)
	}

	// Create README.md
	readme := `# Test Experiment

This is a test experiment for integration testing.

## Usage
python train.py --epochs 2 --lr 0.01 --output_dir ./results
`

	if err := os.WriteFile(readmeFile, []byte(readme), 0600); err != nil {
		t.Fatalf("Failed to create README.md: %v", err)
	}

	// Setup test Redis using fixtures
	redisHelper, err := tests.NewRedisHelper("localhost:6379", 15)
	if err != nil {
		t.Skipf("Redis not available, skipping integration test: %v", err)
	}
	defer func() { _ = redisHelper.Close() }()

	// Test Redis connection
	if err := redisHelper.GetClient().Ping(ctx).Err(); err != nil {
		t.Skipf("Redis not available, skipping integration test: %v", err)
	}

	// Create task queue
	taskQueue, err := tests.NewTaskQueue(&tests.Config{
		RedisAddr: "localhost:6379",
		RedisDB:   15,
	})
	if err != nil {
		t.Fatalf("Failed to create task queue: %v", err)
	}
	defer func() { _ = taskQueue.Close() }()

	// Create ML server (local mode)
	mlServer := tests.NewMLServer()

	// Test 1: Enqueue task (as would happen from TUI)
	task, err := taskQueue.EnqueueTask("test_job", "--epochs 2 --lr 0.01", 5)
	if err != nil {
		t.Fatalf("Failed to enqueue task: %v", err)
	}

	if task.ID == "" {
		t.Fatal("Task ID should not be empty")
	}

	if task.JobName != "test_job" {
		t.Errorf("Expected job name 'test_job', got '%s'", task.JobName)
	}

	if task.Status != "queued" {
		t.Errorf("Expected status 'queued', got '%s'", task.Status)
	}

	// Test 2: Get next task (as worker would)
	nextTask, err := taskQueue.GetNextTask()
	if err != nil {
		t.Fatalf("Failed to get next task: %v", err)
	}

	if nextTask == nil {
		t.Fatal("Should have retrieved a task")
	}

	if nextTask.ID != task.ID {
		t.Errorf("Expected task ID %s, got %s", task.ID, nextTask.ID)
	}

	// Test 3: Update task status to running
	now := time.Now()
	nextTask.Status = statusRunning
	nextTask.StartedAt = &now

	if err := taskQueue.UpdateTask(nextTask); err != nil {
		t.Fatalf("Failed to update task: %v", err)
	}

	// Test 4: Execute job (zero-install style)
	if err := executeZeroInstallJob(mlServer, nextTask, jobBaseDir, trainScript); err != nil {
		t.Fatalf("Failed to execute job: %v", err)
	}

	// Test 5: Update task status to completed
	endTime := time.Now()
	nextTask.Status = statusCompleted
	nextTask.EndedAt = &endTime

	if err := taskQueue.UpdateTask(nextTask); err != nil {
		t.Fatalf("Failed to update final task status: %v", err)
	}

	// Test 6: Verify results
	retrievedTask, err := taskQueue.GetTask(nextTask.ID)
	if err != nil {
		t.Fatalf("Failed to retrieve completed task: %v", err)
	}

	if retrievedTask.Status != statusCompleted {
		t.Errorf("Expected status 'completed', got '%s'", retrievedTask.Status)
	}

	if retrievedTask.StartedAt == nil {
		t.Error("StartedAt should not be nil")
	}

	if retrievedTask.EndedAt == nil {
		t.Error("EndedAt should not be nil")
	}

	// Test 7: Check job status
	jobStatus, err := taskQueue.GetJobStatus("test_job")
	if err != nil {
		t.Fatalf("Failed to get job status: %v", err)
	}

	if jobStatus["status"] != statusCompleted {
		t.Errorf("Expected job status 'completed', got '%s'", jobStatus["status"])
	}

	// Test 8: Record and check metrics
	if err := taskQueue.RecordMetric("test_job", "accuracy", 0.95); err != nil {
		t.Fatalf("Failed to record metric: %v", err)
	}

	metrics, err := taskQueue.GetMetrics("test_job")
	if err != nil {
		t.Fatalf("Failed to get metrics: %v", err)
	}

	if metrics["accuracy"] != "0.95" {
		t.Errorf("Expected accuracy '0.95', got '%s'", metrics["accuracy"])
	}

	t.Log("End-to-end test completed successfully")
}

// executeZeroInstallJob simulates zero-install job execution
func executeZeroInstallJob(server *tests.MLServer, task *tests.Task, baseDir, trainScript string) error {
	// Move job to running directory
	pendingPath := filepath.Join(baseDir, "pending", task.JobName)
	runningPath := filepath.Join(baseDir, statusRunning, task.JobName)

	if err := os.Rename(pendingPath, runningPath); err != nil {
		return fmt.Errorf("failed to move job to running: %w", err)
	}

	// Execute the job (zero-install style - direct Python execution)
	outputDir := filepath.Join(runningPath, "results")
	if err := os.MkdirAll(outputDir, 0750); err != nil {
		return fmt.Errorf("failed to create output directory: %w", err)
	}

	cmd := fmt.Sprintf("cd %s && python3 %s --output_dir %s %s",
		runningPath,
		filepath.Base(trainScript),
		outputDir,
		task.Args,
	)

	output, err := server.Exec(cmd)
	if err != nil {
		return fmt.Errorf("job execution failed: %w, output: %s", err, output)
	}

	// Move to finished directory
	finishedPath := filepath.Join(baseDir, "finished", task.JobName)
	if err := os.Rename(runningPath, finishedPath); err != nil {
		return fmt.Errorf("failed to move job to finished: %w", err)
	}

	return nil
}