require('./toolBar.less');
const React = require('react');
const { useState, useEffect } = React;
const _ = require('lodash')

const MAX_ZOOM = 300;
const MIN_ZOOM = 10;

const ToolBar = ({ onZoomChange, currentPage, onPageChange, totalPages })=>{

	const [zoomLevel, setZoomLevel] = useState(100);
	const [pageInput, setPageInput] = useState(currentPage);

	useEffect(()=>{
		onZoomChange(zoomLevel);
	}, [zoomLevel]);

	useEffect(()=>{
		setPageInput(currentPage);
	}, [currentPage])

	const handleZoomChange = (delta)=>{
		const zoomChange = _.clamp(zoomLevel + delta, MIN_ZOOM, MAX_ZOOM);

		setZoomLevel(zoomChange);
	};

	const handlePageChange = (page)=>{
		setPageInput(page);
	};

	const scrollToPage = (pageNumber) => {
		pageNumber = _.clamp(pageNumber - 1, 0, totalPages - 1);
		const iframe = document.getElementById('BrewRenderer');
		if(iframe && iframe.contentWindow) {
			const brewRenderer = iframe.contentWindow.document.querySelector('.brewRenderer');
			if(brewRenderer) {
				const pages = brewRenderer.querySelectorAll('.page');
				pages[pageNumber]?.scrollIntoView({ block: 'start' });
			}
		}
	};


	const toFit = ()=>{
		const iframe = document.getElementById('BrewRenderer');
		const iframeWidth = iframe.getBoundingClientRect().width;
		const pages = iframe.contentWindow.document.getElementsByClassName('page');

		// find widest page, in case pages are different widths, so that the zoom is adapted to not cut the widest page off screen.
		let widestPage = 0;
		[...pages].forEach((page)=>{
			const width = page.offsetWidth;
			if(width > widestPage)
				widestPage = width;
		});

		const margin = 5;  // extra space so page isn't edge to edge (not truly "to fit")
		const desiredZoom = (iframeWidth / widestPage) * 100;
		const deltaZoom = (desiredZoom - zoomLevel) - margin;
		return deltaZoom;
	}

	return (
		<div className='toolBar'>
			<div className='group'>
				<button
					id='zoom-to-fit'
					className='tool'
					onClick={()=>handleZoomChange(toFit())}
				>
					toFit
				</button>
				<button
					id='zoom-out'
					className='tool'
					onClick={()=>handleZoomChange(-20)}
					disabled={zoomLevel <= MIN_ZOOM}
				>
					<i className='fas fa-magnifying-glass-minus' />
				</button>
				<input
					id='zoom-slider'
					className='range-input tool'
					type='range'
					name='zoom'
					list='zoomLevels'
					min={MIN_ZOOM}
					max={MAX_ZOOM}
					step='1'
					value={zoomLevel}
					onChange={(e)=>{setZoomLevel(parseInt(e.target.value));}}
				/>
				<datalist id='zoomLevels'>
					<option value='100' />
				</datalist>

				<button
					id='zoom-in'
					className='tool'
					onClick={()=>handleZoomChange(20)}
					disabled={zoomLevel >= MAX_ZOOM}
				>
					<i className='fas fa-magnifying-glass-plus' />
				</button>
			</div>

			<div className='group'>
				<button
					id='previous-page'
					className='previousPage tool'
					onClick={()=>scrollToPage(pageInput - 1)}
					disabled={pageInput <= 1}
				>
					<i className='fas fa-arrow-left'></i>
				</button>

				<div className='tool'>
					<input
						id='page-input'
						className='text-input'
						type='text'
						name='page'
						inputMode='numeric'
						pattern='[0-9]'
						value={pageInput}
						onChange={(e)=>{
							handlePageChange(e.target.value == false ? e.target.value : parseInt(e.target.value));}}
						onBlur={()=>scrollToPage(pageInput)}
						onKeyDown={(e)=>{e.key == 'Enter' ? scrollToPage(pageInput) : null;}}
					/>

					<span id='page-count'>/ {totalPages}</span>
				</div>


				<button
					id='next-page'
					className='tool'
					onClick={()=>scrollToPage(pageInput + 1)}
					disabled={pageInput >= totalPages}
				>
					<i className='fas fa-arrow-right'></i>
				</button>
			</div>
		</div>

	);
};

module.exports = ToolBar;