import { RangeSelection, Selection } from "../../selection";
import { CellRef } from "../../types";
import { getRenderedCell, RenderedCell, RenderedGrid } from "./renderGrid";

export interface GridStyles {
  bgFill: string;
  borderStroke: string;
  cellStroke: string;
  cellValueFont: string;
  cellValueLineHeight: string;
}

function excursion(ctx: CanvasRenderingContext2D, f: () => void) {
  ctx.save();
  f();
  ctx.restore();
}

function fillBackground(
  ctx: CanvasRenderingContext2D,
  styles: GridStyles,
  grid: RenderedGrid,
) {
  ctx.clearRect(0, 0, grid.rect.width, grid.rect.height);
  ctx.fillStyle = styles.bgFill;
  ctx.fillRect(0, 0, grid.rect.width, grid.rect.height);
}

function strokeGrid(
  ctx: CanvasRenderingContext2D,
  styles: GridStyles,
  grid: RenderedGrid,
) {
  ctx.strokeStyle = styles.borderStroke;
  ctx.strokeRect(0.5, 0.5, grid.rect.width - 1, grid.rect.height - 1);
}

function strokeGridLines(
  ctx: CanvasRenderingContext2D,
  styles: GridStyles,
  grid: RenderedGrid,
) {
  ctx.strokeStyle = styles.cellStroke;

  grid.renderedRows.forEach((row, renderedRowIndex) => {
    const isLastRow = renderedRowIndex === grid.renderedRows.length - 1;

    row.renderedCells.forEach((cell, cellIndex) => {
      const { topLeft, width, height } = cell.rect;
      const isLastCell = cellIndex === row.renderedCells.length - 1;

      ctx.strokeRect(
        topLeft.x + 0.5,
        topLeft.y + 0.5,
        isLastCell ? width - 1 : width,
        isLastRow ? height - 1 : height,
      );
    });
  });
}

function drawCellValues(
  ctx: CanvasRenderingContext2D,
  styles: GridStyles,
  grid: RenderedGrid,
) {
  grid.renderedRows.forEach((row) =>
    row.renderedCells.forEach((cell) => {
      if (!cell.value) return;
      ctx.fillStyle = "white";
      ctx.textAlign = "center";
      ctx.font = styles.cellValueFont;
      ctx.fillText(
        cell.value,
        cell.rect.center.x,
        cell.rect.center.y + parseInt(styles.cellValueLineHeight) / 4,
      );
    }),
  );
}

export default function drawGrid(
  ctx: CanvasRenderingContext2D,
  styles: GridStyles,
  grid: RenderedGrid,
) {
  excursion(ctx, () => fillBackground(ctx, styles, grid));
  excursion(ctx, () => strokeGridLines(ctx, styles, grid));
  excursion(ctx, () => strokeGrid(ctx, styles, grid));
  excursion(ctx, () => drawCellValues(ctx, styles, grid));
}