// VNC client capture for remote desktop access.
package backends

import (
	"fmt"
	"image"
	"net"
	"time"

	"git.cloonar.com/openclawd/iso-bot/pkg/engine/capture"
)

// VNCConfig holds configuration for VNC client capture.
type VNCConfig struct {
	// Host is the VNC server hostname or IP address.
	Host string `yaml:"host"`

	// Port is the VNC server port (default 5900).
	Port int `yaml:"port"`

	// Password for VNC authentication.
	Password string `yaml:"password"`

	// Shared allows multiple VNC clients to connect simultaneously.
	Shared bool `yaml:"shared"`

	// Encodings specifies preferred pixel encodings (e.g., "raw", "copyrect", "hextile").
	Encodings []string `yaml:"encodings"`

	// ConnectTimeout is the timeout for initial connection.
	ConnectTimeoutMs int `yaml:"connect_timeout_ms"`

	// ReadTimeout is the timeout for frame updates.
	ReadTimeoutMs int `yaml:"read_timeout_ms"`
}

// VNCSource captures frames from a VNC server.
type VNCSource struct {
	config     VNCConfig
	conn       net.Conn
	width      int
	height     int
	pixelFormat VNCPixelFormat
	connected  bool
}

// VNCPixelFormat describes the pixel format used by the VNC server.
type VNCPixelFormat struct {
	BitsPerPixel  uint8
	Depth         uint8
	BigEndian     bool
	TrueColor     bool
	RedMax        uint16
	GreenMax      uint16
	BlueMax       uint16
	RedShift      uint8
	GreenShift    uint8
	BlueShift     uint8
}

// NewVNCSource creates a VNC client capture source.
func NewVNCSource(configMap map[string]interface{}) (capture.Source, error) {
	var config VNCConfig

	// Extract config from map
	if host, ok := configMap["host"].(string); ok {
		config.Host = host
	} else {
		return nil, fmt.Errorf("vnc host is required")
	}

	if port, ok := configMap["port"].(int); ok {
		config.Port = port
	} else {
		config.Port = 5900 // Default VNC port
	}

	if password, ok := configMap["password"].(string); ok {
		config.Password = password
	}

	if shared, ok := configMap["shared"].(bool); ok {
		config.Shared = shared
	} else {
		config.Shared = true // Default to shared access
	}

	if encodings, ok := configMap["encodings"].([]string); ok {
		config.Encodings = encodings
	} else {
		config.Encodings = []string{"raw", "copyrect", "hextile", "rre"} // Default encodings
	}

	if connectTimeout, ok := configMap["connect_timeout_ms"].(int); ok {
		config.ConnectTimeoutMs = connectTimeout
	} else {
		config.ConnectTimeoutMs = 10000 // 10 seconds
	}

	if readTimeout, ok := configMap["read_timeout_ms"].(int); ok {
		config.ReadTimeoutMs = readTimeout
	} else {
		config.ReadTimeoutMs = 5000 // 5 seconds
	}

	return &VNCSource{
		config: config,
	}, nil
}

// Name returns a description of this capture source.
func (v *VNCSource) Name() string {
	return fmt.Sprintf("VNC: %s:%d", v.config.Host, v.config.Port)
}

// Capture grabs a single frame from the VNC server.
func (v *VNCSource) Capture() (image.Image, error) {
	if !v.connected {
		if err := v.connect(); err != nil {
			return nil, fmt.Errorf("failed to connect to VNC server: %w", err)
		}
	}

	// TODO: Implement VNC frame capture
	// 1. Send FramebufferUpdateRequest message
	// 2. Read FramebufferUpdate response
	// 3. Process rectangles with different encodings (Raw, RRE, CoRRE, Hextile, etc.)
	// 4. Update local framebuffer
	// 5. Convert framebuffer to Go image.Image
	return nil, fmt.Errorf("VNC capture not implemented yet")
}

// CaptureRegion grabs a sub-region of the VNC framebuffer.
func (v *VNCSource) CaptureRegion(r capture.Region) (image.Image, error) {
	// TODO: Implement region capture
	// Send FramebufferUpdateRequest for specific region
	return nil, fmt.Errorf("VNC region capture not implemented yet")
}

// Size returns the VNC framebuffer dimensions.
func (v *VNCSource) Size() (width, height int) {
	return v.width, v.height
}

// Close disconnects from the VNC server.
func (v *VNCSource) Close() error {
	v.connected = false
	if v.conn != nil {
		return v.conn.Close()
	}
	return nil
}

// connect establishes a connection to the VNC server and performs handshake.
func (v *VNCSource) connect() error {
	// TODO: Implement VNC connection and handshake
	// 1. Connect to host:port
	// 2. Read protocol version
	// 3. Perform authentication (if required)
	// 4. Send ClientInit message
	// 5. Read ServerInit (framebuffer size, pixel format, etc.)
	// 6. Set pixel format and encodings
	
	addr := fmt.Sprintf("%s:%d", v.config.Host, v.config.Port)
	conn, err := net.DialTimeout("tcp", addr, time.Duration(v.config.ConnectTimeoutMs)*time.Millisecond)
	if err != nil {
		return fmt.Errorf("failed to connect to %s: %w", addr, err)
	}

	v.conn = conn
	v.connected = true

	return fmt.Errorf("VNC handshake not implemented")
}

// performHandshake handles VNC protocol negotiation.
func (v *VNCSource) performHandshake() error {
	// TODO: Implement VNC handshake
	// 1. Protocol version negotiation
	// 2. Security type negotiation
	// 3. Authentication (VNC, None, etc.)
	// 4. ClientInit/ServerInit exchange
	return fmt.Errorf("VNC handshake not implemented")
}

// readFramebufferUpdate reads and processes a framebuffer update.
func (v *VNCSource) readFramebufferUpdate() error {
	// TODO: Implement framebuffer update processing
	// 1. Read FramebufferUpdate message header
	// 2. Process each rectangle based on encoding type
	// 3. Update local framebuffer bitmap
	return fmt.Errorf("VNC framebuffer update not implemented")
}

// requestFramebufferUpdate sends a request for screen updates.
func (v *VNCSource) requestFramebufferUpdate(x, y, width, height int, incremental bool) error {
	// TODO: Send FramebufferUpdateRequest message
	// Message format:
	// - Type: 3 (FramebufferUpdateRequest)
	// - Incremental: 0/1
	// - X, Y, Width, Height: region to update
	return fmt.Errorf("VNC framebuffer request not implemented")
}

// decodeRawEncoding processes Raw encoding (uncompressed pixel data).
func (v *VNCSource) decodeRawEncoding(x, y, width, height int) error {
	// TODO: Read raw pixel data and update framebuffer
	return fmt.Errorf("VNC Raw encoding not implemented")
}

// decodeRREEncoding processes RRE (Rise-and-Run-length Encoding).
func (v *VNCSource) decodeRREEncoding(x, y, width, height int) error {
	// TODO: Decode RRE compressed data
	return fmt.Errorf("VNC RRE encoding not implemented")
}

// decodeHextileEncoding processes Hextile encoding.
func (v *VNCSource) decodeHextileEncoding(x, y, width, height int) error {
	// TODO: Decode Hextile compressed data
	return fmt.Errorf("VNC Hextile encoding not implemented")
}