package com.example.reporting.services.impl.pdf;

import static com.example.reporting.util.DateUtil.formatDate;
import static com.example.reporting.util.Constants.MARGIN_2;
import static com.example.reporting.util.Constants.MARGIN_2_9;
import static com.example.reporting.util.Constants.WHITE_COLOR;
import static com.example.reporting.util.Constants.GREEN_COLOR;
import static com.example.reporting.util.Constants.LIGHTEST_GREEN_COLOR;
import static com.example.reporting.util.PdfUtil.getPdfPTable;
import static com.example.reporting.util.PdfUtil.getPdfPCellSpaningAcross;
import static com.example.reporting.util.PdfUtil.getPdfPCell;

import java.awt.Color;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.text.SimpleDateFormat;
import java.util.Date;

import javax.imageio.ImageIO;

import org.springframework.http.ResponseEntity;

import com.lowagie.text.BadElementException;
import com.lowagie.text.Document;
import com.lowagie.text.DocumentException;
import com.lowagie.text.Element;
import com.lowagie.text.Font;
import com.lowagie.text.Image;
import com.lowagie.text.Paragraph;
import com.lowagie.text.pdf.BaseFont;
import com.lowagie.text.pdf.PdfContentByte;
import com.lowagie.text.pdf.PdfPTable;
import com.lowagie.text.pdf.PdfPageEventHelper;
import com.lowagie.text.pdf.PdfTemplate;
import com.lowagie.text.pdf.PdfWriter;

import com.example.reporting.dto.database.ReportDto;
import com.example.reporting.dto.database.TeamDto;
import com.example.reporting.services.database.ITeamService;
import com.example.reporting.util.DateUtil;
import com.example.reporting.util.ReportUtil;
import com.example.reporting.util.NumberUtils;
import com.example.reporting.util.SessionUtil;

/**
 * Abstract class for PDF conversion.
 *
 * @param <P> the type of the parameter used for conversion
 */
public abstract class PdfConverter<P extends PdfParameter> {

	protected final SimpleDateFormat dateFormat = new SimpleDateFormat("dd.MM.yyyy HH:mm:ss");
	protected final SimpleDateFormat dateFormatSimple = new SimpleDateFormat("dd.MM.yyyy");
	protected final SimpleDateFormat timeFormatSimple = new SimpleDateFormat("HH:mm");
	protected final SimpleDateFormat dateTimeFormatSimple = new SimpleDateFormat("dd.MM.yyyy HH:mm");

	protected BaseFont baseFont;
	protected final Font fontBold22;
	protected final Font fontBold16;
	protected final Font fontBold14;
	protected final Font font14;
	protected final Font font12;
	protected final Font fontBold9;
	protected final Font fontBold10;
	protected final Font font10;

	protected Color conditionalColorStatus;
	protected Color conditionalColorTeam;
	protected Color conditionalColorUnit;
	protected Color conditionalColorId;

	protected final Document document = new Document();
	protected final ByteArrayOutputStream baos = new ByteArrayOutputStream();

	protected PdfConverter() throws DocumentException, IOException {
		try {
			// loading DejaVu from resources
			this.baseFont = BaseFont.createFont("font/DejaVuSans.ttf", BaseFont.IDENTITY_H, BaseFont.EMBEDDED);
		} catch (DocumentException | IOException e) {
			// fallback to Helvetica if loading of DejaVu fails
			this.baseFont = BaseFont.createFont(BaseFont.HELVETICA, BaseFont.IDENTITY_H, BaseFont.EMBEDDED);
		}
		this.fontBold22 = new Font(this.baseFont, 22, Font.BOLD);
		this.fontBold16 = new Font(this.baseFont, 16, Font.BOLD);
		this.fontBold14 = new Font(this.baseFont, 14, Font.BOLD);
		this.font14 = new Font(this.baseFont, 14, Font.NORMAL);
		this.font12 = new Font(this.baseFont, 12, Font.NORMAL);
		this.fontBold9 = new Font(this.baseFont, 9, Font.BOLD);
		this.fontBold10 = new Font(this.baseFont, 10, Font.BOLD);
		this.font10 = new Font(this.baseFont, 10, Font.NORMAL);
	}

	/**
	 * This class is used to create a header and footer for the PDF document.
	 */
	public static class HeaderFooterPageEvent extends PdfPageEventHelper {

		private String headerText;
		private Image headerImage;
		private int currentPageNumber;
		private BaseFont baseFont;
		private PdfTemplate totalPageTemplate;
		private String entityId;

		/**
		 * Constructor for HeaderFooterPageEvent.
		 * 
		 * @param headerText the text to be displayed in the header
		 * @param baseFont the font to be used for the header text
		 * @param headerImage the image to be displayed in the header
		 * @param entityId the ID of the entity
		 * @throws BadElementException if there is an error
		 */
		public HeaderFooterPageEvent(String headerText, BaseFont baseFont, Image headerImage, String entityId) {
			this.headerText = headerText;
			this.headerImage = headerImage;
			this.currentPageNumber = 0;
			this.baseFont = baseFont;
			this.entityId = entityId;
		}

		@Override
		public void onOpenDocument(PdfWriter writer, Document document) {
			this.totalPageTemplate = writer.getDirectContent().createTemplate(50, 50);
		}

		@Override
		public void onEndPage(PdfWriter writer, Document document) {
			PdfContentByte cb = writer.getDirectContent();
			// Increment the current page number
			this.currentPageNumber++;

			String[] lines = headerText.split("\\|");

			// Split the header text if it contains a pipe character
			if (currentPageNumber == 1) {

				// Page text for title page
				cb.beginText();
				cb.setFontAndSize(this.baseFont, 8);
				String entityText = "Entity-ID: " + this.entityId;
				cb.setTextMatrix(MARGIN_2, (MARGIN_2_9 / 2));
				cb.showText(entityText);
				cb.endText();

			} else {

				// Header for regular pages - first line
				cb.beginText();
				cb.setFontAndSize(this.baseFont, 10);
				cb.setTextMatrix(MARGIN_2, document.getPageSize().getHeight() - (MARGIN_2_9 / 2));
				cb.showText(lines[0]);
				cb.endText();

				// Second line (if exists)
				if (lines.length > 1) {
					cb.beginText();
					cb.setFontAndSize(this.baseFont, 10);
					cb.setTextMatrix(MARGIN_2, document.getPageSize().getHeight() - (MARGIN_2_9 / 2) - 12);
					cb.showText(lines[1]);
					cb.endText();
				}

				// Header image for regular pages
				float imageX = document.getPageSize().getWidth() - headerImage.getScaledWidth() - MARGIN_2;
				headerImage.setAbsolutePosition(imageX, document.getPageSize().getHeight() - (MARGIN_2_9 / 2 + 10));
				cb.addImage(headerImage);

				// Footer for regular pages
				cb.beginText();
				cb.setFontAndSize(this.baseFont, 8);
				String footerText = "Page " + currentPageNumber + " of ";
				// Calculate the width of the footer text
				float textWidth = baseFont.getWidthPoint(footerText, 8);
				float rightAlignX = document.getPageSize().getWidth() - textWidth - MARGIN_2 - 11;
				cb.setTextMatrix(rightAlignX, (MARGIN_2_9 / 2));
				cb.showText(footerText);
				cb.endText();
				cb.addTemplate(totalPageTemplate, rightAlignX + textWidth, (MARGIN_2_9 / 2));
				cb.beginText();
				cb.setFontAndSize(this.baseFont, 8);
				String entityText = "Entity-ID: " + this.entityId;
				cb.setTextMatrix(MARGIN_2, (MARGIN_2_9 / 2));
				cb.showText(entityText);
				cb.endText();
			}
		}

		@Override
		public void onCloseDocument(PdfWriter writer, Document document) {
			totalPageTemplate.beginText();
			totalPageTemplate.setFontAndSize(baseFont, 8);
			totalPageTemplate.setTextMatrix(0, 0);
			totalPageTemplate.showText(String.valueOf(currentPageNumber));
			totalPageTemplate.endText();
		}
	}

	protected void generateTitlePage(ReportDto reportDto, PdfWriter writer) throws IOException {
		try (InputStream imageStream = getClass().getClassLoader().getResourceAsStream("logo/logo.png")) {
			Image logoImage = Image.getInstance(ImageIO.read(imageStream), null);
			logoImage.scaleToFit(154, 25); // Resize the image if necessary

			// Create a clone of the image for the header/footer
			Image headerLogoImage = Image.getInstance(logoImage);

			writer.setPageEvent(new HeaderFooterPageEvent(getHeaderText(reportDto), this.baseFont,
				headerLogoImage, reportDto.getEntityId())); // Pass the logo image
			document.setMargins(MARGIN_2, MARGIN_2, MARGIN_2_9, MARGIN_2);

			document.open();

			logoImage.setAlignment(Element.ALIGN_LEFT);
			document.add(logoImage);
			document.add(new Paragraph("\n", fontBold22));

			// Title
			Paragraph title = getPdfTitle(reportDto);
			title.setAlignment(Element.ALIGN_CENTER);
			document.add(title);
			document.add(new Paragraph("\n", font14)); // Add a blank line

			// Owner
			generateParagraphWithBlankLine("Owner: " + reportDto.getOwnerName());

			// Location
			generateParagraphWithBlankLine("Location: " + reportDto.getLocationName());

			// Entity name
			generateParagraphWithBlankLine("Entity Name: " + reportDto.getEntityName());

			// Unit type
			generateParagraphWithBlankLine("Unit Type: " + reportDto.getUnitType());

			// Version
			generateParagraphWithBlankLine("Version: " + reportDto.getVersion());

			getTeamDetails(reportDto);

			// Query date
			generateParagraphWithBlankLine("Query Date: " + formatDate(new Date(), dateFormat));

			// Query by
			generateParagraphWithBlankLine("Query By: " + SessionUtil.getCurrentSession().getCurrentUser().getFullname());

			// Force a new page
			document.newPage();
		}
	}

	protected void generateStatusPage(ReportDto reportDto) {

		// Status title
		Paragraph statusTitle = new Paragraph("STATUS", fontBold16);
		statusTitle.setAlignment(Element.ALIGN_LEFT);
		document.add(statusTitle);

		// Status Table
		PdfPTable statusTable = getPdfPTable(2);

		// Add headers to the table
		statusTable.addCell(getPdfPCellSpaningAcross("Processing Status", fontBold14, GREEN_COLOR, 2)); // header

		// row 1
		statusTable.addCell(getPdfPCell("Version", fontBold10, WHITE_COLOR));
		statusTable.addCell(
			getPdfPCell(NumberUtils.getStringFromBigDecimal(reportDto.getVersion()), font10, WHITE_COLOR));

		// row 2
		statusTable.addCell(getPdfPCell("Status", fontBold10, LIGHTEST_GREEN_COLOR));
		getReportStatus(reportDto, statusTable);

		this.conditionalColorStatus = WHITE_COLOR;
		this.conditionalColorTeam = WHITE_COLOR;

		// row 3
		getTeamDetails(reportDto, statusTable, conditionalColorTeam);

		statusTable.addCell(getPdfPCell("Submission Date", fontBold10, conditionalColorStatus));
		statusTable.addCell(getPdfPCell(DateUtil.formatDate(reportDto.getSubmissionDate(), dateTimeFormatSimple),
			font10, conditionalColorStatus));

		document.add(statusTable);

		// Force a new page
		document.newPage();
	}

	protected void getReportStatus(ReportDto reportDto, PdfPTable statusTable) {
		statusTable.addCell(getPdfPCell(ReportUtil.convertStatusToString(reportDto.getStatus()),
			font10, LIGHTEST_GREEN_COLOR));
	}

	protected void getTeamDetails(ReportDto reportDto, PdfPTable statusTable, Color conditionalColorTeam) {
		// to override in subclass
	}

	protected void addTeamDetails(ReportDto reportDto, PdfPTable statusTable,
			ITeamService teamService, Color conditionalColorTeam) {
		TeamDto teamDto = teamService.getTeamByRootRef(reportDto.getRootRef());
		String teamName = teamDto != null ? teamDto.getTeamName() : "No team assigned/found";
		statusTable.addCell(getPdfPCell("Assigned Team", fontBold10, conditionalColorTeam));
		statusTable.addCell(getPdfPCell(teamName, font10, conditionalColorTeam));

		this.conditionalColorStatus = LIGHTEST_GREEN_COLOR;
		this.conditionalColorUnit = WHITE_COLOR;
		this.conditionalColorId = WHITE_COLOR;
	}

	/**
	 * This method is used to convert into PDF
	 * 
	 * @param param the parameter to be converted to a PDF document and returns it as a byte array.
	 * 
	 * @return a ResponseEntity containing the PDF document as a byte array
	 * 
	 * @throws IOException possible exception
	 */
	public abstract ResponseEntity<byte[]> convert(P param) throws IOException;

	abstract String getHeaderText(ReportDto reportDto);

	protected void getTeamDetails(ReportDto reportDto) {
		// implementation for specific types
	}

	protected void generateParagraphWithBlankLine(String text) {
		Paragraph paragraph = new Paragraph(text, font14);
		paragraph.setAlignment(Element.ALIGN_CENTER);
		document.add(paragraph);
		document.add(new Paragraph("\n", font14)); // Add a blank line
	}

	abstract Paragraph getPdfTitle(ReportDto reportDto);
}