package errors

import (
	"fmt"
	"strings"
)

// ConnectionError represents SSH connection errors with helpful hints
type ConnectionError struct {
	Type    string // "auth", "network", "timeout", "config", "unknown"
	Message string
	Details string
	Hints   []string
}

// Error implements the error interface
func (e *ConnectionError) Error() string {
	return fmt.Sprintf("Connection Error (%s): %s\nDetails: %s", e.Type, e.Message, e.Details)
}

// NewConnectionError creates a new ConnectionError
func NewConnectionError(errType, message, details string, hints []string) *ConnectionError {
	return &ConnectionError{
		Type:    errType,
		Message: message,
		Details: details,
		Hints:   hints,
	}
}

// HandleSSHError processes SSH errors and returns user-friendly errors
func HandleSSHError(err error) *ConnectionError {
	if err == nil {
		return nil
	}

	errStr := err.Error()

	switch {
	case strings.Contains(errStr, "connection refused"):
		return &ConnectionError{
			Type:    "network",
			Message: "Cannot connect to server",
			Details: errStr,
			Hints:   []string{"Check if server is running", "Verify firewall rules", "Confirm hostname and port"},
		}

	case strings.Contains(errStr, "authentication failed"), strings.Contains(errStr, "unable to authenticate"):
		return &ConnectionError{
			Type:    "auth",
			Message: "Authentication failed",
			Details: errStr,
			Hints:   []string{"Verify username and password", "Check SSH key is loaded", "Test with native SSH client"},
		}

	case strings.Contains(errStr, "timeout"), strings.Contains(errStr, "timed out"):
		return &ConnectionError{
			Type:    "timeout",
			Message: "Connection timeout",
			Details: errStr,
			Hints:   []string{"Check network connectivity", "Try increasing timeout", "Verify server is reachable"},
		}

	case strings.Contains(errStr, "no such host"), strings.Contains(errStr, "hostname"):
		return &ConnectionError{
			Type:    "config",
			Message: "Invalid hostname",
			Details: errStr,
			Hints:   []string{"Verify hostname spelling", "Check DNS resolution", "Try IP address instead"},
		}

	case strings.Contains(errStr, "permission denied"):
		return &ConnectionError{
			Type:    "auth",
			Message: "Permission denied",
			Details: errStr,
			Hints:   []string{"Check user permissions on server", "Verify account is not locked", "Check authentication method"},
		}

	default:
		return &ConnectionError{
			Type:    "unknown",
			Message: "Connection failed",
			Details: errStr,
			Hints:   []string{"Check host configuration", "Verify network settings", "Test with standard SSH client"},
		}
	}
}

// FormatConnectionError formats connection error for user-friendly display
func FormatConnectionError(err *ConnectionError) string {
	var output strings.Builder

	output.WriteString(fmt.Sprintf("❌ Connection Error: %s\n\n", err.Message))
	output.WriteString(fmt.Sprintf("Details: %s\n\n", err.Details))

	if len(err.Hints) > 0 {
		output.WriteString("Possible solutions:\n")
		for i, hint := range err.Hints {
			output.WriteString(fmt.Sprintf("  %d. %s\n", i+1, hint))
		}
	}

	return output.String()
}