import React from "react";
import { findDOMNode } from "react-dom";

import { snapToMany, snapWithin, applySnap } from "../snapUtils";

const WINDOW_HEIGHT = 116;
const WINDOW_WIDTH = 275;

class WindowManager extends React.Component {
  constructor(props) {
    super(props);
    this.windowNodes = [];
    this.state = {};
    this.getRef = this.getRef.bind(this);
    this.handleMouseDown = this.handleMouseDown.bind(this);
  }

  componentDidMount() {
    window.addEventListener("resize", this.centerWindows.bind(this));
    const { innerHeight, innerWidth } = window;
    if (innerHeight || innerWidth) {
      this.centerWindows();
    }
  }

  centerWindows() {
    const { innerHeight, innerWidth } = window;
    const state = {};
    const children = this.validChildren();
    const totalHeight = children.length * WINDOW_HEIGHT;
    children.forEach((child, i) => {
      const offset = WINDOW_HEIGHT * i;
      state[i] = {
        left: innerWidth / 2 - WINDOW_WIDTH / 2,
        top: innerHeight / 2 - totalHeight / 2 + offset
      };
    });
    this.setState(state);
  }

  getRef(node) {
    this.windowNodes.push(node);
  }

  otherWindows(element) {
    const domNodes = this.windowNodes.map(findDOMNode);
    return domNodes.filter(node => node !== element);
  }

  nodeInfo(node) {
    const child = node.childNodes[0];
    const { height, width } = child.getBoundingClientRect();
    const { offsetLeft, offsetTop } = node;
    return {
      x: offsetLeft,
      y: offsetTop,
      height,
      width
    };
  }

  handleMouseDown(i, e) {
    if (!e.target.classList.contains("draggable")) {
      return;
    }
    const mouseStart = {
      x: e.clientX,
      y: e.clientY
    };

    const windowStart = this.nodeInfo(e.currentTarget);

    const otherWindowNodes = this.otherWindows(e.currentTarget).map(
      this.nodeInfo
    );

    const browserSize = {
      width: window.innerWidth,
      height: window.innerHeight
    };

    const handleMouseMove = ee => {
      const diff = {
        x: ee.clientX - mouseStart.x,
        y: ee.clientY - mouseStart.y
      };

      const proposedWindow = {
        ...windowStart,
        x: windowStart.x + diff.x,
        y: windowStart.y + diff.y
      };

      const snappedToOthers = snapToMany(proposedWindow, otherWindowNodes);
      const snappedToBrowser = snapWithin(proposedWindow, browserSize);

      const newPosition = applySnap(
        proposedWindow,
        snappedToBrowser,
        snappedToOthers
      );

      this.setState({ [i]: { top: newPosition.y, left: newPosition.x } });
    };

    window.addEventListener("mouseup", () => {
      window.removeEventListener("mousemove", handleMouseMove);
    });
    window.addEventListener("mousemove", handleMouseMove);
  }

  validChildren() {
    return React.Children.toArray(this.props.children).filter(child => child);
  }

  render() {
    const style = {
      position: "absolute"
    };

    const parentStyle = {
      position: "absolute",
      width: 0,
      height: 0,
      top: 0,
      left: 0
    };
    return (
      <div style={parentStyle}>
        {this.validChildren().map((child, i) => {
          const position = this.state[i];
          /* eslint-disable react/jsx-no-bind */
          return (
            position &&
            <div
              onMouseDown={e => this.handleMouseDown(i, e)}
              ref={this.getRef}
              style={{ ...style, ...position }}
              key={i}
            >
              {child}
            </div>
          );
          /* eslint-enable react/jsx-no-bind */
        })}
      </div>
    );
  }
}
export default WindowManager;