'use strict';

const obsidian = require('obsidian');

const MIN_SCALE = 1;
const MAX_SCALE = 10;
const DOUBLE_TAP_MS = 350;

class ImageFullPlugin extends obsidian.Plugin {
	onload() {
		this.lastTapTime = 0;
		this.lastTapTarget = null;
		this.openViewers = new Set();
		this.registerDomEvent(document, 'dblclick', this.handleDblClick.bind(this), { capture: true });
		this.registerDomEvent(document, 'touchend', this.handleTouchEnd.bind(this), { capture: true });
	}

	onunload() {
		for (const closeFn of this.openViewers) closeFn();
		this.openViewers.clear();
	}

	handleDblClick(evt) {
		const target = evt.target;
		if (!(target instanceof HTMLImageElement)) return;
		if (!this.isEmbeddedImage(target)) return;
		if (target.closest('.imagefull-overlay')) return;

		evt.preventDefault();
		evt.stopPropagation();
		this.openFullscreen(target);
	}

	handleTouchEnd(evt) {
		if (evt.touches.length > 0) return;
		const target = evt.target;
		if (!(target instanceof HTMLImageElement)) return;
		if (!this.isEmbeddedImage(target)) return;
		if (target.closest('.imagefull-overlay')) return;

		const now = Date.now();
		if (now - this.lastTapTime < DOUBLE_TAP_MS && this.lastTapTarget === target) {
			evt.preventDefault();
			evt.stopPropagation();
			this.lastTapTime = 0;
			this.lastTapTarget = null;
			this.openFullscreen(target);
		} else {
			this.lastTapTime = now;
			this.lastTapTarget = target;
		}
	}

	isEmbeddedImage(img) {
		if (!img.src) return false;
		return !!img.closest(
			'.markdown-preview-view, .markdown-rendered, .markdown-source-view, .cm-editor, .internal-embed'
		);
	}

	openFullscreen(sourceImg) {
		const overlay = document.createElement('div');
		overlay.className = 'imagefull-overlay';

		const img = document.createElement('img');
		img.className = 'imagefull-image';
		img.src = sourceImg.currentSrc || sourceImg.src;
		img.alt = sourceImg.alt || '';
		img.draggable = false;

		const hint = document.createElement('div');
		hint.className = 'imagefull-hint';
		hint.textContent = 'Pinch to zoom · Two-finger swipe to pan · Double-click to close';

		overlay.appendChild(img);
		overlay.appendChild(hint);
		document.body.appendChild(overlay);

		const state = {
			scale: 1,
			tx: 0,
			ty: 0,
			pinching: false,
			suppressClick: false,
			startDist: 0,
			startScale: 1,
			startMidX: 0,
			startMidY: 0,
			startTx: 0,
			startTy: 0,
			panStartX: 0,
			panStartY: 0,
		};

		const apply = () => {
			img.setCssProps({
				'--imagefull-tx': `${state.tx}px`,
				'--imagefull-ty': `${state.ty}px`,
				'--imagefull-scale': `${state.scale}`,
			});
			img.toggleClass('imagefull-zoomed', state.scale > 1.01);
		};

		const reset = () => {
			state.scale = 1;
			state.tx = 0;
			state.ty = 0;
			apply();
		};

		const clampPan = () => {
			const rect = img.getBoundingClientRect();
			const maxX = Math.max(window.innerWidth * 0.4, (rect.width - window.innerWidth) / 2 + 60);
			const maxY = Math.max(window.innerHeight * 0.4, (rect.height - window.innerHeight) / 2 + 60);
			state.tx = Math.max(-maxX, Math.min(maxX, state.tx));
			state.ty = Math.max(-maxY, Math.min(maxY, state.ty));
		};

		const onTouchStart = (e) => {
			if (e.touches.length === 2) {
				e.preventDefault();
				state.pinching = true;
				state.suppressClick = true;
				const t1 = e.touches[0], t2 = e.touches[1];
				const dx = t1.clientX - t2.clientX;
				const dy = t1.clientY - t2.clientY;
				state.startDist = Math.hypot(dx, dy) || 1;
				state.startScale = state.scale;
				state.startMidX = (t1.clientX + t2.clientX) / 2;
				state.startMidY = (t1.clientY + t2.clientY) / 2;
				state.startTx = state.tx;
				state.startTy = state.ty;
			}
		};

		const onTouchMove = (e) => {
			if (!state.pinching || e.touches.length !== 2) return;
			e.preventDefault();
			const t1 = e.touches[0], t2 = e.touches[1];
			const dx = t1.clientX - t2.clientX;
			const dy = t1.clientY - t2.clientY;
			const dist = Math.hypot(dx, dy) || 1;
			const newScale = Math.max(
				MIN_SCALE,
				Math.min(MAX_SCALE, state.startScale * (dist / state.startDist))
			);
			const midX = (t1.clientX + t2.clientX) / 2;
			const midY = (t1.clientY + t2.clientY) / 2;
			const cx = window.innerWidth / 2;
			const cy = window.innerHeight / 2;
			const k = newScale / state.startScale;
			state.tx = state.startTx + (midX - state.startMidX) + (state.startMidX - cx) * (1 - k);
			state.ty = state.startTy + (midY - state.startMidY) + (state.startMidY - cy) * (1 - k);
			state.scale = newScale;
			clampPan();
			apply();
		};

		const onTouchEnd = (e) => {
			if (e.touches.length < 2) state.pinching = false;
			setTimeout(() => { state.suppressClick = false; }, 250);
		};

		const onWheel = (e) => {
			e.preventDefault();
			if (e.ctrlKey) {
				const delta = -e.deltaY * 0.02;
				const newScale = Math.max(MIN_SCALE, Math.min(MAX_SCALE, state.scale * (1 + delta)));
				if (newScale === state.scale) return;
				const cx = window.innerWidth / 2;
				const cy = window.innerHeight / 2;
				const k = newScale / state.scale;
				state.tx = (state.tx + (e.clientX - cx)) * k - (e.clientX - cx);
				state.ty = (state.ty + (e.clientY - cy)) * k - (e.clientY - cy);
				state.scale = newScale;
				clampPan();
				apply();
			} else {
				state.tx -= e.deltaX;
				state.ty -= e.deltaY;
				clampPan();
				apply();
			}
		};

		let mouseDown = false;
		const onMouseDown = (e) => {
			if (state.scale <= 1.01) return;
			mouseDown = true;
			state.panStartX = e.clientX;
			state.panStartY = e.clientY;
			state.startTx = state.tx;
			state.startTy = state.ty;
			img.addClass('imagefull-dragging');
		};
		const onMouseMove = (e) => {
			if (!mouseDown) return;
			state.tx = state.startTx + (e.clientX - state.panStartX);
			state.ty = state.startTy + (e.clientY - state.panStartY);
			if (Math.abs(e.clientX - state.panStartX) + Math.abs(e.clientY - state.panStartY) > 4) {
				state.suppressClick = true;
			}
			clampPan();
			apply();
		};
		const onMouseUp = () => {
			if (mouseDown) {
				mouseDown = false;
				img.removeClass('imagefull-dragging');
				setTimeout(() => { state.suppressClick = false; }, 50);
			}
		};

		const close = () => {
			overlay.remove();
			document.removeEventListener('keydown', onKey);
			this.openViewers.delete(close);
		};

		const onOverlayDblClick = () => {
			if (state.pinching) return;
			close();
		};

		let lastTap = 0;
		const onOverlayTap = (e) => {
			if (e.touches && e.touches.length > 0) return;
			if (state.pinching) { lastTap = 0; return; }
			if (state.suppressClick) { lastTap = 0; return; }
			const now = Date.now();
			if (now - lastTap < DOUBLE_TAP_MS) {
				lastTap = 0;
				e.preventDefault();
				close();
			} else {
				lastTap = now;
			}
		};

		const onKey = (e) => {
			if (e.key === 'Escape') close();
			else if (e.key === '0') reset();
		};

		overlay.addEventListener('dblclick', onOverlayDblClick);
		overlay.addEventListener('wheel', onWheel, { passive: false });
		overlay.addEventListener('mousedown', onMouseDown);
		overlay.addEventListener('mousemove', onMouseMove);
		overlay.addEventListener('mouseup', onMouseUp);
		overlay.addEventListener('mouseleave', onMouseUp);
		overlay.addEventListener('touchstart', onTouchStart, { passive: false });
		overlay.addEventListener('touchmove', onTouchMove, { passive: false });
		overlay.addEventListener('touchend', onTouchEnd);
		overlay.addEventListener('touchcancel', onTouchEnd);
		overlay.addEventListener('touchend', onOverlayTap);
		document.addEventListener('keydown', onKey);

		this.openViewers.add(close);
		apply();
	}
}

module.exports = ImageFullPlugin;