components: prepare components for multiple line selections

src/components/App/App.tsx

@@ -14,6 +14,7 @@ export default function App(): JSX.Element {
         <Board
           numRows={10}
           numCols={10}
+          numLines={1}
         />
       </div>
       <div />

src/components/Board/Board.scss

@@ -19,19 +19,13 @@ $LetterHoverColor: #d9d9ff;
   height: 100%;
 }
 
-.Line {
-  stroke: red;
-  stroke-width: 10px;
-  opacity: 0.3;
-}
-
 .Board {
   display: grid;
   justify-content: center;
   grid-template-columns: repeat(10, 60px);
 }
 
-.Letter {
+.Cell {
   width: 60px;
   height: 60px;
   font-weight: bold;

src/components/Board/Board.tsx

@@ -1,92 +1,101 @@
 import React from 'react';
 
+import Line from '../Line/Line';
+
 import './Board.scss';
 
-interface IBoardProps {
-  numRows: number;
-  numCols: number;
-}
-
-interface Position {
+export type Point = {
   x: number;
   y: number;
 }
 
+interface IBoardProps {
+  numRows: number;
+  numCols: number;
+  numLines: number;
+}
+
 interface IBoardState {
-  board: string[][];
-  isSelectingWord: boolean;
-  startPos: Position;
+  cells: string[][];
+  lines: string[];
+  isSelecting: boolean;
+  startPos: Point;
+  endPos: Point;
 }
 
 export default class Board extends React.Component<IBoardProps, IBoardState> {
-  private line: React.RefObject<SVGLineElement>;
-  private line1: Position;
-  private line2: Position;
-  private letterSize: number;
-
   constructor(props: IBoardProps) {
     super(props);
 
     this.state = {
-      board: Array(props.numCols).fill(Array(props.numRows).fill('A')),
-      isSelectingWord: false,
+      cells: Array(props.numCols).fill(Array(props.numRows).fill('A')),
+      lines: Array(props.numLines).fill(''),
+      isSelecting: false,
       startPos: {x: 0, y: 0},
+      endPos: {x: 0, y: 0},
+    }
   }
 
-    this.line = React.createRef();
-    this.line1 = {x: 0, y: 0};
-    this.line2 = {x: 0, y: 0};
-    this.letterSize = 60;
+  handleMouseDown(startPos: Point) {
+    this.setState({...this.state, startPos, isSelecting: true});
   }
 
-  handleMouseDown(startPos: Position) {
-    this.setState({...this.state, startPos, isSelectingWord: true});
+  handleMouseUp(endPos: Point) {
+    this.setState({...this.state, endPos, isSelecting: false});
   }
 
-  handleMouseUp(startPos: Position) {
-    this.line1 = startPos;
-    this.line2 = this.state.startPos;
+  handleMouseOver(currentPos: Point) {
+    if (!this.state.isSelecting) {
+      this.setState({...this.state});
+    } else {
 
-    this.setState({...this.state, startPos, isSelectingWord: false});
+    }
   }
 
-  handleMouseOver(currentPos: Position) {
-    if (!this.state.isSelectingWord)
-      return;
-  }
-
-  render(): JSX.Element {
-    let letters =
-      this.state.board.map((oy, y) =>
-        oy.map((s, x) =>
+  renderCell(s: string, pos: Point): JSX.Element {
+    return (
       <button
-            key={`${x}${y}`}
-            className="Letter"
-            onMouseUp={() => this.handleMouseUp({x, y})}
-            onMouseDown={() => this.handleMouseDown({x, y})}
-            onMouseOver={() => this.handleMouseOver({x, y})}
+        className="Cell"
+        key={`Cell${pos.x}${pos.y}`}
+        onMouseUp={() => this.handleMouseUp(pos)}
+        onMouseDown={() => this.handleMouseDown(pos)}
+        onMouseOver={() => this.handleMouseOver(pos)}
       >
         {s}
       </button>
-      ));
+    );
+  }
+
+  renderLine(x: number): JSX.Element {
+    return (
+      <Line
+        key={`Line${x}`}
+        startPos={this.state.startPos}
+        endPos={this.state.endPos}
+        cellSize={60}
+      />
+    );
+  }
+
+  render(): JSX.Element {
+    let cells =
+      this.state.cells.map((oy, y) =>
+        oy.map((s, x) =>
+          this.renderCell(s, {x, y})));
+
+    let lines = this.state.lines.map((ox, x) =>
+        this.renderLine(x));
 
     return (
       <div className="Container">
         <div className="Content">
           <div className="Board">
-            {letters}
+            {cells}
           </div>
         </div>
         <div className="Overlay">
           <svg className="Canvas">
-            <line
-              className="Line"
-              ref={this.line}
-              x1={`${this.line1.x * this.letterSize + this.letterSize / 2}`}
-              y1={`${this.line1.y * this.letterSize + this.letterSize / 2}`}
-              x2={`${this.line2.x * this.letterSize + this.letterSize / 2}`}
-              y2={`${this.line2.y * this.letterSize + this.letterSize / 2}`}
-            />
+            {lines}
           </svg>
         </div>
       </div>

src/components/Line/Line.scss

@@ -0,0 +1,5 @@
+.Line {
+  stroke: red;
+  stroke-width: 10px;
+  opacity: 0.3;
+}

src/components/Line/Line.tsx

@@ -0,0 +1,25 @@
+import React from 'react';
+
+import {Point} from '../Board/Board'
+
+import './Line.scss';
+
+interface ILineProps {
+  startPos: Point;
+  endPos: Point;
+  cellSize: number;
+}
+
+export default function Line(props: ILineProps): JSX.Element {
+  const pos = (v: number) => v * props.cellSize + props.cellSize / 2;
+
+  return (
+    <line
+      className="Line"
+      x1={`${pos(props.endPos.x)}`}
+      y1={`${pos(props.endPos.y)}`}
+      x2={`${pos(props.startPos.x)}`}
+      y2={`${pos(props.startPos.y)}`}
+    />
+  );
+}