/*  OpenTally: Open-source election vote counting
 *  Copyright © 2021–2022 Lee Yingtong Li (RunasSudo)
 *
 *  This program is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU Affero General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU Affero General Public License for more details.
 *
 *  You should have received a copy of the GNU Affero General Public License
 *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */

async function printResult() {
	// Remove highlighted stage comment if any
	for (let elLi of document.getElementById('olStageComments').children) {
		elLi.classList.remove('highlight');
	}
	
	let printableWidth; // Printable width in CSS pixels
	let paperSize = document.getElementById('selPaperSize').value;
	if (paperSize === 'A4') {
		printableWidth = (29.7 - 2) * 96 / 2.54;
	} else if (paperSize === 'A3') {
		printableWidth = (42.0 - 2) * 96 / 2.54;
	} else if (paperSize === 'letter') {
		printableWidth = (27.9 - 2) * 96 / 2.54;
	}
	printableWidth = Math.round(printableWidth);
	
	let wprint = window.open('');
	wprint.document.title = 'OpenTally Report';
	
	// Add stylesheets
	let numToLoad = 0;
	let numLoaded = -1;
	
	function onLoadStylesheet() {
		numLoaded++;
		if (numLoaded == numToLoad) {
			wprint.print();
		}
	}
	
	for (let elCSSBase of document.querySelectorAll('head link')) {
		numToLoad++;
		let elCSS = wprint.document.createElement('link');
		elCSS.rel = elCSSBase.rel;
		elCSS.type = elCSSBase.type;
		if (elCSSBase.href.endsWith('?v=GITVERSION')) {
			elCSS.href = elCSSBase.href.replace('?v=GITVERSION', '?v=' + Math.random());
		} else {
			elCSS.href = elCSSBase.href;
		}
		
		elCSS.onload = onLoadStylesheet;
		wprint.document.head.appendChild(elCSS);
	}
	
	// Configure printing
	let elStyle = wprint.document.createElement('style');
	elStyle.innerHTML = '@page { size: ' + paperSize + ' landscape; margin: 1cm; } @media print { body { padding: 0; } }';
	wprint.document.head.appendChild(elStyle);
	
	let elContainer = wprint.document.createElement('div');
	elContainer.id = 'printContainer';
	elContainer.style.width = printableWidth + 'px';
	wprint.document.body.appendChild(elContainer);
	
	// Copy result logs 1
	let divResultLogs1 = document.getElementById('resultLogs1');
	let divResultLogs2 = wprint.document.createElement('div');
	divResultLogs2.innerHTML = divResultLogs1.innerHTML;
	elContainer.appendChild(divResultLogs2);
	
	// Parse table, accounting for colspan/rowspan
	let elTrs1 = document.getElementById('result').rows;
	let rows = [];
	for (let elTr1 of elTrs1) {
		rows.push([]);
	}
	for (let r = 0; r < elTrs1.length; r++) {
		for (let c = 0; c < elTrs1[r].cells.length; c++) {
			let elTd1 = elTrs1[r].cells[c];
			rows[r].push(elTd1);
			
			let colspan = elTd1.getAttribute('colspan');
			if (colspan !== null) {
				colspan = parseInt(colspan);
				// Add ghost cells
				for (let i = 1; i < colspan; i++) {
					rows[r].push(null);
				}
			}
			
			let rowspan = elTd1.getAttribute('rowspan');
			// NB: Only works for rowspan in first column
			if (rowspan !== null && c == 0) {
				rowspan = parseInt(rowspan);
				// Add ghost cells
				for (let i = 1; i < rowspan; i++) {
					rows[r + i].push(null);
				}
			}
		}
	}
	
	function copyColumn(c, elTrs2) {
		let tdsAdded = [];
		for (let r = 0; r < rows.length; r++) {
			if (c < rows[r].length) {
				let elTd1 = rows[r][c];
				if (elTd1 !== null) {
					let elTd2 = wprint.document.createElement('td');
					elTd2.innerHTML = elTd1.innerHTML;
					elTd2.className = elTd1.className;
					if (elTd1.getAttribute('rowspan') !== null) { elTd2.setAttribute('rowspan', elTd1.getAttribute('rowspan')); }
					if (elTd1.getAttribute('colspan') !== null) { elTd2.setAttribute('colspan', elTd1.getAttribute('colspan')); }
					if (elTd1.getAttribute('style') !== null) { elTd2.setAttribute('style', elTd1.getAttribute('style')); }
					elTrs2[r].appendChild(elTd2);
					tdsAdded.push(elTd2);
				}
			}
		}
		return tdsAdded;
	}
	
	async function copyTableColumns(startCol) {
		let modelRow = document.getElementById('selReport').value === 'ballots_votes' ? rows[4] : rows[3];
		
		// Add table
		let elTable2 = wprint.document.createElement('table');
		elTable2.className = 'result';
		if (startCol > 1) {
			elTable2.style.pageBreakBefore = 'always';
		}
		elContainer.appendChild(elTable2);
		
		// Add rows
		let elTrs2 = [];
		for (let elTr1 of elTrs1) {
			let elTr2 = wprint.document.createElement('tr');
			elTr2.className = elTr1.className;
			elTrs2.push(elTr2);
			elTable2.appendChild(elTr2);
		}
		
		// Copy first column
		copyColumn(0, elTrs2);
		
		// How many columns to copy?
		let totalWidth = modelRow[0].clientWidth;
		let endCol;
		for (endCol = startCol; endCol < modelRow.length; ) {
			// Check first column
			if (totalWidth + modelRow[endCol].clientWidth > printableWidth) {
				break;
			}
			
			if (
				(document.getElementById('selReport').value === 'ballots_votes' && endCol + 1 < modelRow.length) ||
				(document.getElementById('selReport').value === 'votes_transposed' && endCol != 1 && endCol + 1 < modelRow.length)
			) {
				// Check second column
				if (totalWidth + modelRow[endCol].clientWidth + modelRow[endCol + 1].clientWidth > printableWidth) {
					break;
				}
			}
			
			// Ok!
			totalWidth += modelRow[endCol].clientWidth;
			endCol++;
			
			if (
				(document.getElementById('selReport').value === 'ballots_votes' && endCol < modelRow.length) ||
				(document.getElementById('selReport').value === 'votes_transposed' && endCol != 2 && endCol + 1 < modelRow.length)
			) {
				// Second column
				totalWidth += modelRow[endCol].clientWidth;
				endCol++;
			}
		}
		
		// Copy columns
		let stages = [];
		for (let c = startCol; c < endCol; c++) {
			if (rows[0][c] !== null && rows[0][c].querySelector('a')) {
				// Track stage headings copied
				stages.push(parseInt(rows[0][c].querySelector('a').innerHTML));
			}
			copyColumn(c, elTrs2);
		}
		
		// Copy stage comments
		elContainer.insertAdjacentHTML('beforeend', '<p>Stage comments:</p>');
		let olStageComments2 = wprint.document.createElement('ol');
		olStageComments2.start = stages[0];
		elContainer.append(olStageComments2);
		for (let stage of stages) {
			olStageComments2.insertAdjacentHTML('beforeend', olStageComments.children[stage-1].outerHTML);
		}
		
		if (endCol < modelRow.length) {
			// Start new table if columns remain
			copyTableColumns(endCol);
		} else {
			// Copy winning candidates
			elContainer.insertAdjacentHTML('beforeend', '<p>Count complete. The winning candidates are, in order of election:</p>');
			elContainer.insertAdjacentHTML('beforeend', document.getElementById('resultLogs2').lastElementChild.outerHTML);
		}
	}
	
	// Adjust results table to width
	document.getElementById('resultsDiv').style.width = printableWidth + 'px';
	await new Promise(window.requestAnimationFrame); // Allow DOM to update
	
	// Copy table
	await copyTableColumns(1);
	
	// Restore original view
	document.getElementById('resultsDiv').style.width = 'auto';
	
	// Trigger print when ready
	onLoadStylesheet();
}