package proxmox

import (
	"context"
	"fmt"
	"time"

	"github.com/pkg/errors"
)

// Client represents a Proxmox API client
type Client struct {
	endpoint string
	username string
	password string
	token    string
}

// NewClient creates a new Proxmox API client
func NewClient(endpoint, username, password string) *Client {
	return &Client{
		endpoint: endpoint,
		username: username,
		password: password,
	}
}

// RetryConfig defines retry behavior
type RetryConfig struct {
	MaxRetries int
	BaseDelay  time.Duration
	MaxDelay   time.Duration
}

// DefaultRetryConfig returns default retry configuration
func DefaultRetryConfig() RetryConfig {
	return RetryConfig{
		MaxRetries: 3,
		BaseDelay:  time.Second,
		MaxDelay:   30 * time.Second,
	}
}

// RetryableError indicates an error that should be retried
type RetryableError struct {
	Err        error
	RetryAfter time.Duration
}

func (e *RetryableError) Error() string {
	return e.Err.Error()
}

// IsRetryable checks if an error is retryable
func IsRetryable(err error) bool {
	if err == nil {
		return false
	}
	_, ok := err.(*RetryableError)
	return ok
}

// Retry executes a function with retry logic
func Retry(ctx context.Context, fn func() error, config RetryConfig) error {
	var lastErr error

	for attempt := 0; attempt <= config.MaxRetries; attempt++ {
		if attempt > 0 {
			delay := config.BaseDelay * time.Duration(1<<uint(attempt-1))
			if delay > config.MaxDelay {
				delay = config.MaxDelay
			}

			select {
			case <-ctx.Done():
				return ctx.Err()
			case <-time.After(delay):
			}
		}

		err := fn()
		if err == nil {
			return nil
		}

		lastErr = err

		if !IsRetryable(err) {
			return err
		}

		if attempt < config.MaxRetries {
			if retryErr, ok := err.(*RetryableError); ok && retryErr.RetryAfter > 0 {
				select {
				case <-ctx.Done():
					return ctx.Err()
				case <-time.After(retryErr.RetryAfter):
				}
			}
		}
	}

	return errors.Wrapf(lastErr, "failed after %d retries", config.MaxRetries)
}

// CreateVM creates a virtual machine
func (c *Client) CreateVM(ctx context.Context, spec VMSpec) (*VM, error) {
	config := DefaultRetryConfig()

	var vm *VM
	err := Retry(ctx, func() error {
		var retryErr error
		vm, retryErr = c.createVM(ctx, spec)
		if retryErr != nil {
			// Check if error is retryable (network errors, temporary failures)
			if isNetworkError(retryErr) || isTemporaryError(retryErr) {
				return &RetryableError{Err: retryErr}
			}
			return retryErr
		}
		return nil
	}, config)

	return vm, err
}

// createVM performs the actual VM creation
func (c *Client) createVM(ctx context.Context, spec VMSpec) (*VM, error) {
	// TODO: Implement actual Proxmox API call
	return nil, fmt.Errorf("not implemented")
}

// UpdateVM updates a virtual machine
func (c *Client) UpdateVM(ctx context.Context, vmID int, spec VMSpec) (*VM, error) {
	config := DefaultRetryConfig()

	var vm *VM
	err := Retry(ctx, func() error {
		var retryErr error
		vm, retryErr = c.updateVM(ctx, vmID, spec)
		if retryErr != nil {
			if isNetworkError(retryErr) || isTemporaryError(retryErr) {
				return &RetryableError{Err: retryErr}
			}
			return retryErr
		}
		return nil
	}, config)

	return vm, err
}

func (c *Client) updateVM(ctx context.Context, vmID int, spec VMSpec) (*VM, error) {
	// TODO: Implement actual Proxmox API call
	return nil, fmt.Errorf("not implemented")
}

// DeleteVM deletes a virtual machine
func (c *Client) DeleteVM(ctx context.Context, vmID int) error {
	config := DefaultRetryConfig()

	return Retry(ctx, func() error {
		err := c.deleteVM(ctx, vmID)
		if err != nil {
			if isNetworkError(err) || isTemporaryError(err) {
				return &RetryableError{Err: err}
			}
			return err
		}
		return nil
	}, config)
}

func (c *Client) deleteVM(ctx context.Context, vmID int) error {
	// TODO: Implement actual Proxmox API call
	return fmt.Errorf("not implemented")
}

// GetVMStatus gets the status of a virtual machine
func (c *Client) GetVMStatus(ctx context.Context, vmID int) (*VMStatus, error) {
	config := DefaultRetryConfig()

	var status *VMStatus
	err := Retry(ctx, func() error {
		var retryErr error
		status, retryErr = c.getVMStatus(ctx, vmID)
		if retryErr != nil {
			if isNetworkError(retryErr) || isTemporaryError(retryErr) {
				return &RetryableError{Err: retryErr}
			}
			return retryErr
		}
		return nil
	}, config)

	return status, err
}

func (c *Client) getVMStatus(ctx context.Context, vmID int) (*VMStatus, error) {
	// TODO: Implement actual Proxmox API call
	return nil, fmt.Errorf("not implemented")
}

// Helper functions
func isNetworkError(err error) bool {
	if err == nil {
		return false
	}
	errStr := err.Error()
	return contains(errStr, "network") || contains(errStr, "timeout") || contains(errStr, "connection")
}

func isTemporaryError(err error) bool {
	if err == nil {
		return false
	}
	errStr := err.Error()
	return contains(errStr, "temporary") || contains(errStr, "503") || contains(errStr, "502")
}

func contains(s, substr string) bool {
	return len(s) >= len(substr) && (s == substr || len(substr) == 0 || indexOfSubstring(s, substr) >= 0)
}

func indexOfSubstring(s, substr string) int {
	for i := 0; i <= len(s)-len(substr); i++ {
		if s[i:i+len(substr)] == substr {
			return i
		}
	}
	return -1
}

// VMSpec represents VM specification
type VMSpec struct {
	Node    string
	Name    string
	CPU     int
	Memory  string
	Disk    string
	Storage string
	Network string
	Image   string
}

// VM represents a virtual machine
type VM struct {
	ID      int
	Name    string
	Status  string
	IP      string
	Node    string
	Created time.Time
}

// VMStatus represents VM status
type VMStatus struct {
	State     string
	IPAddress string
	CPU       float64
	Memory    int64
}