package froala.editor.video;

import java.io.File;
import java.io.IOException;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.tika.Tika;

/**
 * 동영상 스트리밍 전송
 * @since 2021. 6. 18.
 * @author 임종호
 * <PRE>
 * -----------------------
 * 개정이력
 * 2021. 6. 18. 임종호 : 최초작성
 * </PRE>
 */
public class StreamingResponse {
	public static final int DEFAULT_BUFFER_SIZE = 204800;

	private static final long DEFAULT_EXPIRE_TIME = 604800000L;

	public Range write(File file, HttpServletRequest request, HttpServletResponse response) throws IOException {
		Range range = null;
		String fileName = (String) request.getAttribute("originFileNm");
		String rangeStr = request.getHeader("range");

		if (rangeStr != null) {
			if (rangeStr.endsWith("-")) {
				rangeStr = rangeStr + (file.length() - 1);
			}

			int idxm = rangeStr.trim().indexOf("-");
			range = new Range(Long.parseLong(rangeStr.substring(6, idxm)), Long.parseLong(rangeStr.substring(idxm + 1)), file.length());
			long partSize = 0;
			if (range.getStart() > 0) {
				range.setPart(true);
			}
			range.setPartSize(partSize);
		} else {
			range = new Range(0L, file.length() - 1, file.length());
		}
		range.setPartSize(range.getEnd() - range.getStart() + 1);
		if (range.getEnd() == 0) {
			range.setEnd(range.getStart() + DEFAULT_BUFFER_SIZE - 1);
		}

		if (range.getEnd() > range.getTotal() - 1) {
			range.setEnd(range.getTotal() - 1);
		}

		String eTag = file.getName() + "_" + file.lastModified();

		// mime type 지정
		Tika tika = new Tika();
		String mime = tika.detect(file);
		response.setContentType(mime);

		response.reset();
		response.setStatus(range.isPart() ? HttpServletResponse.SC_PARTIAL_CONTENT : HttpServletResponse.SC_OK);
		response.setHeader("Content-Range", "bytes " + range.getStart() + "-" + range.getEnd() + "/" + range.getTotal());
		response.setHeader("Accept-Ranges", "bytes");
		response.setHeader("Content-Length", "" + range.getPartSize());
		response.setBufferSize(DEFAULT_BUFFER_SIZE);
		response.setHeader("Content-Disposition", "inline;filename=\"" + fileName + "\"");
		response.setHeader("ETag", eTag);
		response.setDateHeader("Last-Modified", file.lastModified());
		response.setDateHeader("Expires", System.currentTimeMillis() + DEFAULT_EXPIRE_TIME);

		return range;

	}
}