package controller

import (
	"bytes"
	"encoding/base64"
	"fmt"
	"image"
	"image/png"

	rdpengine "ezops/pkg/rdp"

	"github.com/gorilla/websocket"
)

// encodeRDPBitmapPNG 将实时 RGBA 脏矩形压缩为 PNG，避免原始整帧占满低带宽 WebSocket。 // Logan.Li
func encodeRDPBitmapPNG(frame rdpengine.ServerFrame) (rdpengine.ServerFrame, error) {
	if frame.Type != "bitmap" || len(frame.RGBA) == 0 {
		return frame, nil
	}
	if frame.Width <= 0 || frame.Height <= 0 {
		return rdpengine.ServerFrame{}, fmt.Errorf("RDP 位图尺寸无效: %dx%d", frame.Width, frame.Height)
	}
	required := frame.Width * frame.Height * 4
	if len(frame.RGBA) < required {
		return rdpengine.ServerFrame{}, fmt.Errorf("RDP 位图数据不足: got=%d want=%d", len(frame.RGBA), required)
	}

	img := image.NewRGBA(image.Rect(0, 0, frame.Width, frame.Height))
	copy(img.Pix, frame.RGBA[:required])
	var buf bytes.Buffer
	encoder := png.Encoder{CompressionLevel: png.BestSpeed}
	if err := encoder.Encode(&buf, img); err != nil {
		return rdpengine.ServerFrame{}, fmt.Errorf("压缩 RDP 位图失败: %w", err)
	}

	frame.Image = "data:image/png;base64," + base64.StdEncoding.EncodeToString(buf.Bytes())
	frame.RGBA = nil
	return frame, nil
}

// writeCompressedRDPBitmap 发送浏览器已支持的 JSON PNG 帧，兼容现有前端绘制逻辑。 // Logan.Li
func writeCompressedRDPBitmap(conn *websocket.Conn, frame rdpengine.ServerFrame) error {
	encoded, err := encodeRDPBitmapPNG(frame)
	if err != nil {
		return err
	}
	return conn.WriteJSON(encoded)
}