import PlainDraggable from 'plain-draggable';
import { onRemove, animateRectTransition } from './utils';

export class Layout {
  constructor(options = {}) {
    if (!options.name) throw Error('Layout name is not given');
    this.name = options.name;
    this.enterHandler = options.enterHandler;
    this.leaveHandler = options.leaveHandler;
  }
  valueOf = () => this.name;
}

export class SideBySide extends Layout {
  name = 'side-by-side';

  enterHandler = ({ container, htmlHolder, showcase }) => {
    const bar = document.createElement('div');
    bar.className = 'bar';
    bar.innerHTML = '<div class="bar-handle"></div>';
    const handle = bar.querySelector('.bar-handle');
    container.appendChild(bar);

    // Resize views by value
    const resizeByLeft = left => {
      htmlHolder.style.width = left + 'px';
      showcase.style.width =
        parseFloat(getComputedStyle(container).width) - left + 'px';
    };

    const draggable = new PlainDraggable(bar, {
      handle: handle,
      containment: { left: '25%', top: 0, right: '75%', height: 0 },
    });
    draggable.draggableCursor = 'grab';

    draggable.onDrag = pos => {
      handle.style.transform = 'unset';
      resizeByLeft(pos.left);
    };
    draggable.onDragEnd = _ => {
      handle.removeAttribute('style');
    };

    onRemove(bar, () => draggable.remove());
  };

  leaveHandler = ({ container }) => {
    container.querySelector('.bar')?.remove();
  };
}

export class Overlay extends Layout {
  name = 'overlay';

  saveLeftTopAsData = element => {
    const { left, top } = element.getBoundingClientRect();
    element.setAttribute('data-left', left);
    element.setAttribute('data-top', top);
  };

  addDraggable = element => {
    // Make sure current element always on top
    const siblings = Array.from(
      element.parentElement?.querySelectorAll(':scope > *') ?? [],
    );
    let popTimer = null;
    element.onmouseover = () => {
      popTimer = setTimeout(() => {
        siblings.forEach(e => e.style.removeProperty('z-index'));
        element.style.zIndex = '9001';
      }, 200);
    };
    element.onmouseout = () => {
      clearTimeout(popTimer);
    };

    // Add draggable part
    const draggablePart = document.createElement('div');
    element.appendChild(draggablePart);
    draggablePart.className = 'draggable-part';
    draggablePart.innerHTML = '<div class="handle">\u2630</div>';

    // Add draggable instance
    const { left, top } = element.getBoundingClientRect();
    const draggable = new PlainDraggable(element, {
      top: top,
      left: left,
      handle: draggablePart,
      snap: { x: { step: 20 }, y: { step: 20 } },
    });

    // FIXME use pure CSS to hide utils
    const utils = element.querySelector('.utils');
    draggable.onDragStart = () => {
      utils.style.display = 'none';
      element.classList.add('drag');
    };

    draggable.onDragEnd = () => {
      utils.style = '';
      element.classList.remove('drag');
      element.style.zIndex = '9000';
    };

    // Reposition draggable instance when resized
    new ResizeObserver(() => {
      try {
        draggable.position();
      } catch (_) {
        null;
      }
    }).observe(element);

    // Callback for remove
    onRemove(element, () => {
      draggable.remove();
    });
  };

  enterHandler = ({ htmlHolder, blocks }) => {
    // FIXME It is weird rect from this method and this scope are different...
    blocks.forEach(this.saveLeftTopAsData);

    // Create draggable blocks and set each position by previous one
    let [left, top] = [20, 20];
    blocks.forEach(block => {
      const originLeft = Number(block.getAttribute('data-left'));
      const originTop = Number(block.getAttribute('data-top'));

      // Create draggable block
      const wrapper = document.createElement('div');
      wrapper.classList.add('draggable-block');
      wrapper.innerHTML = `
        <div class="utils">
          <div id="close">\u274C</div>
          <div id="plus-font-size" ">\u2795</div>
          <div id="minus-font-size">\u2796</div>
        </div>
      `;
      wrapper.title = 'Middle-click to hide block';
      wrapper.onmouseup = e => {
        // Hide block with middle click
        if (e.button === 1) {
          wrapper.classList.add('hide');
        }
      };

      // Set DOMRect for wrapper
      wrapper.appendChild(block);
      wrapper.style.left = left + 'px';
      wrapper.style.top = top + 'px';
      htmlHolder.appendChild(wrapper);
      const { width } = wrapper.getBoundingClientRect();
      left += width + 30;
      if (left > window.innerWidth) {
        top += 200;
        left = left % window.innerWidth;
      }

      // Animation for DOMRect
      animateRectTransition(
        wrapper,
        { left: originLeft, top: originTop },
        { resume: true, duration: 300 },
      ).finished.finally(() => this.addDraggable(wrapper));

      // Trivial case:
      // This hack make sure utils remains at the same place even when wrapper resized
      // Prevent DOMRect changes when user clicking plus/minus button many times
      const utils = wrapper.querySelector('.utils');
      utils.onmouseover = () => {
        const { left, top } = utils.getBoundingClientRect();
        utils.style.cssText = `visibility: visible; z-index: 9000; position: fixed; transition: unset; left: ${left}px; top: ${top}px;`;
        document.body.appendChild(utils);
      };
      utils.onmouseout = () => {
        wrapper.appendChild(utils);
        utils.removeAttribute('style');
      };

      // Close button
      wrapper.querySelector('#close').onclick = () => {
        wrapper.classList.add('hide');
        utils.removeAttribute('style');
      };
      // Plus/Minus font-size of content
      wrapper.querySelector('#plus-font-size').onclick = () => {
        const fontSize = parseFloat(getComputedStyle(block).fontSize) / 16;
        block.style.fontSize = `${fontSize + 0.2}rem`;
      };
      wrapper.querySelector('#minus-font-size').onclick = () => {
        const fontSize = parseFloat(getComputedStyle(block).fontSize) / 16;
        block.style.fontSize = `${fontSize - 0.2}rem`;
      };
    });
  };

  leaveHandler = ({ htmlHolder, blocks }) => {
    const resumeFromDraggable = block => {
      const draggableContainer = block.closest('.draggable-block');
      if (!draggableContainer) return;
      htmlHolder.appendChild(block);
      draggableContainer.remove();
    };
    blocks.forEach(resumeFromDraggable);
  };
}