package object_storage

import (
	"context"
	"database/sql"
	"fmt"
	"os"
	"os/exec"
	"path/filepath"
	"strings"
	"time"

	"github.com/atlasos/calypso/internal/common/database"
	"github.com/atlasos/calypso/internal/common/logger"
)

// SetupService handles object storage setup operations
type SetupService struct {
	db     *database.DB
	logger *logger.Logger
}

// NewSetupService creates a new setup service
func NewSetupService(db *database.DB, log *logger.Logger) *SetupService {
	return &SetupService{
		db:     db,
		logger: log,
	}
}

// PoolDatasetInfo represents a pool with its datasets
type PoolDatasetInfo struct {
	PoolID    string              `json:"pool_id"`
	PoolName  string              `json:"pool_name"`
	Datasets  []DatasetInfo       `json:"datasets"`
}

// DatasetInfo represents a dataset that can be used for object storage
type DatasetInfo struct {
	ID         string `json:"id"`
	Name       string `json:"name"`
	FullName   string `json:"full_name"` // pool/dataset
	MountPoint string `json:"mount_point"`
	Type       string `json:"type"`
	UsedBytes  int64  `json:"used_bytes"`
	AvailableBytes int64 `json:"available_bytes"`
}

// GetAvailableDatasets returns all pools with their datasets that can be used for object storage
func (s *SetupService) GetAvailableDatasets(ctx context.Context) ([]PoolDatasetInfo, error) {
	// Get all pools
	poolsQuery := `
		SELECT id, name
		FROM zfs_pools
		WHERE is_active = true
		ORDER BY name
	`

	rows, err := s.db.QueryContext(ctx, poolsQuery)
	if err != nil {
		return nil, fmt.Errorf("failed to query pools: %w", err)
	}
	defer rows.Close()

	var pools []PoolDatasetInfo
	for rows.Next() {
		var pool PoolDatasetInfo
		if err := rows.Scan(&pool.PoolID, &pool.PoolName); err != nil {
			s.logger.Warn("Failed to scan pool", "error", err)
			continue
		}

		// Get datasets for this pool
		datasetsQuery := `
			SELECT id, name, type, mount_point, used_bytes, available_bytes
			FROM zfs_datasets
			WHERE pool_name = $1 AND type = 'filesystem'
			ORDER BY name
		`

		datasetRows, err := s.db.QueryContext(ctx, datasetsQuery, pool.PoolName)
		if err != nil {
			s.logger.Warn("Failed to query datasets", "pool", pool.PoolName, "error", err)
			pool.Datasets = []DatasetInfo{}
			pools = append(pools, pool)
			continue
		}

		var datasets []DatasetInfo
		for datasetRows.Next() {
			var ds DatasetInfo
			var mountPoint sql.NullString

			if err := datasetRows.Scan(&ds.ID, &ds.Name, &ds.Type, &mountPoint, &ds.UsedBytes, &ds.AvailableBytes); err != nil {
				s.logger.Warn("Failed to scan dataset", "error", err)
				continue
			}

			ds.FullName = fmt.Sprintf("%s/%s", pool.PoolName, ds.Name)
			if mountPoint.Valid {
				ds.MountPoint = mountPoint.String
			} else {
				ds.MountPoint = ""
			}

			datasets = append(datasets, ds)
		}
		datasetRows.Close()

		pool.Datasets = datasets
		pools = append(pools, pool)
	}

	return pools, nil
}

// SetupRequest represents a request to setup object storage
type SetupRequest struct {
	PoolName    string `json:"pool_name" binding:"required"`
	DatasetName string `json:"dataset_name" binding:"required"`
	CreateNew   bool   `json:"create_new"` // If true, create new dataset instead of using existing
}

// SetupResponse represents the response after setup
type SetupResponse struct {
	DatasetPath string `json:"dataset_path"`
	MountPoint  string `json:"mount_point"`
	Message     string `json:"message"`
}

// SetupObjectStorage configures MinIO to use a specific ZFS dataset
func (s *SetupService) SetupObjectStorage(ctx context.Context, req SetupRequest) (*SetupResponse, error) {
	var datasetPath, mountPoint string

	// Normalize dataset name - if it already contains pool name, use it as-is
	var fullDatasetName string
	if strings.HasPrefix(req.DatasetName, req.PoolName+"/") {
		// Dataset name already includes pool name (e.g., "pool/dataset")
		fullDatasetName = req.DatasetName
	} else {
		// Dataset name is just the name (e.g., "dataset"), combine with pool
		fullDatasetName = fmt.Sprintf("%s/%s", req.PoolName, req.DatasetName)
	}

	if req.CreateNew {
		// Create new dataset for object storage
		
		// Check if dataset already exists
		checkCmd := exec.CommandContext(ctx, "sudo", "zfs", "list", "-H", "-o", "name", fullDatasetName)
		if err := checkCmd.Run(); err == nil {
			return nil, fmt.Errorf("dataset %s already exists", fullDatasetName)
		}

		// Create dataset
		createCmd := exec.CommandContext(ctx, "sudo", "zfs", "create", fullDatasetName)
		if output, err := createCmd.CombinedOutput(); err != nil {
			return nil, fmt.Errorf("failed to create dataset: %s - %w", string(output), err)
		}

		// Get mount point
		getMountCmd := exec.CommandContext(ctx, "sudo", "zfs", "get", "-H", "-o", "value", "mountpoint", fullDatasetName)
		mountOutput, err := getMountCmd.Output()
		if err != nil {
			return nil, fmt.Errorf("failed to get mount point: %w", err)
		}
		mountPoint = strings.TrimSpace(string(mountOutput))

		datasetPath = fullDatasetName
		s.logger.Info("Created new dataset for object storage", "dataset", fullDatasetName, "mount_point", mountPoint)
	} else {
		// Use existing dataset
		// fullDatasetName already set above
		
		// Verify dataset exists
		checkCmd := exec.CommandContext(ctx, "sudo", "zfs", "list", "-H", "-o", "name", fullDatasetName)
		if err := checkCmd.Run(); err != nil {
			return nil, fmt.Errorf("dataset %s does not exist", fullDatasetName)
		}

		// Get mount point
		getMountCmd := exec.CommandContext(ctx, "sudo", "zfs", "get", "-H", "-o", "value", "mountpoint", fullDatasetName)
		mountOutput, err := getMountCmd.Output()
		if err != nil {
			return nil, fmt.Errorf("failed to get mount point: %w", err)
		}
		mountPoint = strings.TrimSpace(string(mountOutput))

		datasetPath = fullDatasetName
		s.logger.Info("Using existing dataset for object storage", "dataset", fullDatasetName, "mount_point", mountPoint)
	}

	// Ensure mount point directory exists
	if mountPoint != "none" && mountPoint != "" {
		if err := os.MkdirAll(mountPoint, 0755); err != nil {
			return nil, fmt.Errorf("failed to create mount point directory: %w", err)
		}
	} else {
		// If no mount point, use default path
		mountPoint = filepath.Join("/opt/calypso/data/pool", req.PoolName, req.DatasetName)
		if err := os.MkdirAll(mountPoint, 0755); err != nil {
			return nil, fmt.Errorf("failed to create default directory: %w", err)
		}
	}

	// Update MinIO configuration to use the selected dataset
	if err := s.updateMinIOConfig(ctx, mountPoint); err != nil {
		s.logger.Warn("Failed to update MinIO configuration", "error", err)
		// Continue anyway, configuration is saved to database
	}

	// Save configuration to database
	_, err := s.db.ExecContext(ctx, `
		INSERT INTO object_storage_config (dataset_path, mount_point, pool_name, dataset_name, created_at, updated_at)
		VALUES ($1, $2, $3, $4, NOW(), NOW())
		ON CONFLICT (id) DO UPDATE
		SET dataset_path = $1, mount_point = $2, pool_name = $3, dataset_name = $4, updated_at = NOW()
	`, datasetPath, mountPoint, req.PoolName, req.DatasetName)

	if err != nil {
		// If table doesn't exist, just log warning
		s.logger.Warn("Failed to save configuration to database (table may not exist)", "error", err)
	}

	return &SetupResponse{
		DatasetPath: datasetPath,
		MountPoint:  mountPoint,
		Message:     fmt.Sprintf("Object storage configured to use dataset %s at %s. MinIO service needs to be restarted to use the new dataset.", datasetPath, mountPoint),
	}, nil
}

// GetCurrentSetup returns the current object storage configuration
func (s *SetupService) GetCurrentSetup(ctx context.Context) (*SetupResponse, error) {
	// Check if table exists first
	var tableExists bool
	checkQuery := `
		SELECT EXISTS (
			SELECT FROM information_schema.tables 
			WHERE table_schema = 'public' 
			AND table_name = 'object_storage_config'
		)
	`
	err := s.db.QueryRowContext(ctx, checkQuery).Scan(&tableExists)
	if err != nil {
		s.logger.Warn("Failed to check if object_storage_config table exists", "error", err)
		return nil, nil // Return nil if can't check
	}

	if !tableExists {
		s.logger.Debug("object_storage_config table does not exist")
		return nil, nil // No table, no configuration
	}

	query := `
		SELECT dataset_path, mount_point, pool_name, dataset_name
		FROM object_storage_config
		ORDER BY updated_at DESC
		LIMIT 1
	`

	var resp SetupResponse
	var poolName, datasetName string
	err = s.db.QueryRowContext(ctx, query).Scan(&resp.DatasetPath, &resp.MountPoint, &poolName, &datasetName)
	if err == sql.ErrNoRows {
		s.logger.Debug("No configuration found in database")
		return nil, nil // No configuration found
	}
	if err != nil {
		// Check if error is due to table not existing or permission denied
		errStr := err.Error()
		if strings.Contains(errStr, "does not exist") || strings.Contains(errStr, "permission denied") {
			s.logger.Debug("Table does not exist or permission denied, returning nil", "error", errStr)
			return nil, nil // Return nil instead of error
		}
		s.logger.Error("Failed to scan current setup", "error", err)
		return nil, fmt.Errorf("failed to get current setup: %w", err)
	}

	s.logger.Debug("Found current setup", "dataset_path", resp.DatasetPath, "mount_point", resp.MountPoint, "pool", poolName, "dataset", datasetName)
	// Use dataset_path directly since it already contains the full path
	resp.Message = fmt.Sprintf("Using dataset %s at %s", resp.DatasetPath, resp.MountPoint)
	return &resp, nil
}

// UpdateObjectStorage updates the object storage configuration to use a different dataset
// This will update the configuration but won't migrate existing data
func (s *SetupService) UpdateObjectStorage(ctx context.Context, req SetupRequest) (*SetupResponse, error) {
	// First check if there's existing configuration
	currentSetup, err := s.GetCurrentSetup(ctx)
	if err != nil {
		return nil, fmt.Errorf("failed to check current setup: %w", err)
	}

	if currentSetup == nil {
		// No existing setup, just do normal setup
		return s.SetupObjectStorage(ctx, req)
	}

	// There's existing setup, proceed with update
	var datasetPath, mountPoint string

	// Normalize dataset name - if it already contains pool name, use it as-is
	var fullDatasetName string
	if strings.HasPrefix(req.DatasetName, req.PoolName+"/") {
		// Dataset name already includes pool name (e.g., "pool/dataset")
		fullDatasetName = req.DatasetName
	} else {
		// Dataset name is just the name (e.g., "dataset"), combine with pool
		fullDatasetName = fmt.Sprintf("%s/%s", req.PoolName, req.DatasetName)
	}

	if req.CreateNew {
		// Create new dataset for object storage
		
		// Check if dataset already exists
		checkCmd := exec.CommandContext(ctx, "sudo", "zfs", "list", "-H", "-o", "name", fullDatasetName)
		if err := checkCmd.Run(); err == nil {
			return nil, fmt.Errorf("dataset %s already exists", fullDatasetName)
		}

		// Create dataset
		createCmd := exec.CommandContext(ctx, "sudo", "zfs", "create", fullDatasetName)
		if output, err := createCmd.CombinedOutput(); err != nil {
			return nil, fmt.Errorf("failed to create dataset: %s - %w", string(output), err)
		}

		// Get mount point
		getMountCmd := exec.CommandContext(ctx, "sudo", "zfs", "get", "-H", "-o", "value", "mountpoint", fullDatasetName)
		mountOutput, err := getMountCmd.Output()
		if err != nil {
			return nil, fmt.Errorf("failed to get mount point: %w", err)
		}
		mountPoint = strings.TrimSpace(string(mountOutput))

		datasetPath = fullDatasetName
		s.logger.Info("Created new dataset for object storage update", "dataset", fullDatasetName, "mount_point", mountPoint)
	} else {
		// Use existing dataset
		// fullDatasetName already set above
		
		// Verify dataset exists
		checkCmd := exec.CommandContext(ctx, "sudo", "zfs", "list", "-H", "-o", "name", fullDatasetName)
		if err := checkCmd.Run(); err != nil {
			return nil, fmt.Errorf("dataset %s does not exist", fullDatasetName)
		}

		// Get mount point
		getMountCmd := exec.CommandContext(ctx, "sudo", "zfs", "get", "-H", "-o", "value", "mountpoint", fullDatasetName)
		mountOutput, err := getMountCmd.Output()
		if err != nil {
			return nil, fmt.Errorf("failed to get mount point: %w", err)
		}
		mountPoint = strings.TrimSpace(string(mountOutput))

		datasetPath = fullDatasetName
		s.logger.Info("Using existing dataset for object storage update", "dataset", fullDatasetName, "mount_point", mountPoint)
	}

	// Ensure mount point directory exists
	if mountPoint != "none" && mountPoint != "" {
		if err := os.MkdirAll(mountPoint, 0755); err != nil {
			return nil, fmt.Errorf("failed to create mount point directory: %w", err)
		}
	} else {
		// If no mount point, use default path
		mountPoint = filepath.Join("/opt/calypso/data/pool", req.PoolName, req.DatasetName)
		if err := os.MkdirAll(mountPoint, 0755); err != nil {
			return nil, fmt.Errorf("failed to create default directory: %w", err)
		}
	}

	// Update configuration in database
	_, err = s.db.ExecContext(ctx, `
		UPDATE object_storage_config
		SET dataset_path = $1, mount_point = $2, pool_name = $3, dataset_name = $4, updated_at = NOW()
		WHERE id = (SELECT id FROM object_storage_config ORDER BY updated_at DESC LIMIT 1)
	`, datasetPath, mountPoint, req.PoolName, req.DatasetName)

	if err != nil {
		// If update fails, try insert
		_, err = s.db.ExecContext(ctx, `
			INSERT INTO object_storage_config (dataset_path, mount_point, pool_name, dataset_name, created_at, updated_at)
			VALUES ($1, $2, $3, $4, NOW(), NOW())
			ON CONFLICT (dataset_path) DO UPDATE
			SET mount_point = $2, pool_name = $3, dataset_name = $4, updated_at = NOW()
		`, datasetPath, mountPoint, req.PoolName, req.DatasetName)
		if err != nil {
			s.logger.Warn("Failed to update configuration in database", "error", err)
		}
	}

	// Update MinIO configuration to use the selected dataset
	if err := s.updateMinIOConfig(ctx, mountPoint); err != nil {
		s.logger.Warn("Failed to update MinIO configuration", "error", err)
		// Continue anyway, configuration is saved to database
	} else {
		// Restart MinIO service to apply new configuration
		if err := s.restartMinIOService(ctx); err != nil {
			s.logger.Warn("Failed to restart MinIO service", "error", err)
			// Continue anyway, user can restart manually
		}
	}

	return &SetupResponse{
		DatasetPath: datasetPath,
		MountPoint:  mountPoint,
		Message:     fmt.Sprintf("Object storage updated to use dataset %s at %s. Note: Existing data in previous dataset (%s) is not migrated automatically. MinIO service has been restarted.", datasetPath, mountPoint, currentSetup.DatasetPath),
	}, nil
}

// updateMinIOConfig updates MinIO configuration file to use dataset mount point directly
// Note: MinIO erasure coding requires direct directory paths, not symlinks
func (s *SetupService) updateMinIOConfig(ctx context.Context, datasetMountPoint string) error {
	configFile := "/opt/calypso/conf/minio/minio.conf"

	// Ensure dataset mount point directory exists and has correct ownership
	if err := os.MkdirAll(datasetMountPoint, 0755); err != nil {
		return fmt.Errorf("failed to create dataset mount point directory: %w", err)
	}

	// Set ownership to minio-user so MinIO can write to it
	if err := exec.CommandContext(ctx, "sudo", "chown", "-R", "minio-user:minio-user", datasetMountPoint).Run(); err != nil {
		s.logger.Warn("Failed to set ownership on dataset mount point", "path", datasetMountPoint, "error", err)
		// Continue anyway, might already have correct ownership
	}

	// Set permissions
	if err := exec.CommandContext(ctx, "sudo", "chmod", "755", datasetMountPoint).Run(); err != nil {
		s.logger.Warn("Failed to set permissions on dataset mount point", "path", datasetMountPoint, "error", err)
	}

	s.logger.Info("Prepared dataset mount point for MinIO", "path", datasetMountPoint)

	// Read current config file
	configContent, err := os.ReadFile(configFile)
	if err != nil {
		// If file doesn't exist, create it
		if os.IsNotExist(err) {
			configContent = []byte(fmt.Sprintf("MINIO_ROOT_USER=admin\nMINIO_ROOT_PASSWORD=HqBX1IINqFynkWFa\nMINIO_VOLUMES=%s\n", datasetMountPoint))
		} else {
			return fmt.Errorf("failed to read MinIO config file: %w", err)
		}
	} else {
		// Update MINIO_VOLUMES in config
		lines := strings.Split(string(configContent), "\n")
		updated := false
		for i, line := range lines {
			if strings.HasPrefix(strings.TrimSpace(line), "MINIO_VOLUMES=") {
				lines[i] = fmt.Sprintf("MINIO_VOLUMES=%s", datasetMountPoint)
				updated = true
				break
			}
		}
		if !updated {
			// Add MINIO_VOLUMES if not found
			lines = append(lines, fmt.Sprintf("MINIO_VOLUMES=%s", datasetMountPoint))
		}
		configContent = []byte(strings.Join(lines, "\n"))
	}

	// Write updated config using sudo
	// Write temp file to a location we can write to
	userTempFile := fmt.Sprintf("/tmp/minio.conf.%d.tmp", os.Getpid())
	if err := os.WriteFile(userTempFile, configContent, 0644); err != nil {
		return fmt.Errorf("failed to write temp config file: %w", err)
	}
	defer os.Remove(userTempFile) // Cleanup

	// Copy temp file to config location with sudo
	if err := exec.CommandContext(ctx, "sudo", "cp", userTempFile, configFile).Run(); err != nil {
		return fmt.Errorf("failed to update config file: %w", err)
	}

	// Set proper ownership and permissions
	if err := exec.CommandContext(ctx, "sudo", "chown", "minio-user:minio-user", configFile).Run(); err != nil {
		s.logger.Warn("Failed to set config file ownership", "error", err)
	}
	if err := exec.CommandContext(ctx, "sudo", "chmod", "644", configFile).Run(); err != nil {
		s.logger.Warn("Failed to set config file permissions", "error", err)
	}

	s.logger.Info("Updated MinIO configuration", "config_file", configFile, "volumes", datasetMountPoint)

	return nil
}

// restartMinIOService restarts the MinIO service to apply new configuration
func (s *SetupService) restartMinIOService(ctx context.Context) error {
	// Restart MinIO service using sudo
	cmd := exec.CommandContext(ctx, "sudo", "systemctl", "restart", "minio.service")
	if err := cmd.Run(); err != nil {
		return fmt.Errorf("failed to restart MinIO service: %w", err)
	}

	// Wait a moment for service to start
	time.Sleep(2 * time.Second)

	// Verify service is running
	checkCmd := exec.CommandContext(ctx, "sudo", "systemctl", "is-active", "minio.service")
	output, err := checkCmd.Output()
	if err != nil {
		return fmt.Errorf("failed to check MinIO service status: %w", err)
	}

	status := strings.TrimSpace(string(output))
	if status != "active" {
		return fmt.Errorf("MinIO service is not active after restart, status: %s", status)
	}

	s.logger.Info("MinIO service restarted successfully")
	return nil
}