export type Grid = number[][];

const getVisibility = (row: number, column: number, grid: Grid) => {
  const height = grid[row][column];
  // Check each direction
  // if we get to the outside return true
  // if we get to a taller tree end the for loop in a super hacky way to move along
  for (let i = row + 1; i <= grid.length; i++) {
    if (i === grid.length) {
      return true;
    }
    if (grid[i][column] >= height) {
      i = grid.length + 1;
    }
  }
  for (let i = row - 1; i >= -1; i--) {
    if (i === -1) {
      return true;
    }
    if (grid[i][column] >= height) {
      i = -2;
    }
  }
  for (let i = column + 1; i <= grid[row].length; i++) {
    if (i === grid[row].length) {
      return true;
    }
    if (grid[row][i] >= height) {
      i = grid[row].length + 1;
    }
  }
  for (let i = column - 1; i >= -1; i--) {
    if (i === -1) {
      return true;
    }
    if (grid[row][i] >= height) {
      i = -2;
    }
  }
  return false;
};

const getViewingScore = (row: number, column: number, grid: Grid) => {
  const height = grid[row][column];
  // Similar to getVisbility, but this time add up trees along the way and no early returns
  let right = 0;
  for (let i = row + 1; i < grid.length; i++) {
    if (grid[i][column] >= height) {
      i = grid.length;
    }
    right++;
  }
  let left = 0;
  for (let i = row - 1; i >= 0; i--) {
    if (grid[i][column] >= height) {
      i = -1;
    }
    left++;
  }
  let down = 0;
  for (let i = column + 1; i < grid[row].length; i++) {
    if (grid[row][i] >= height) {
      i = grid[row].length;
    }
    down++;
  }
  let up = 0;
  for (let i = column - 1; i >= 0; i--) {
    if (grid[row][i] >= height) {
      i = -1;
    }
    up++;
  }

  return right * left * up * down;
};

// Part I
export const getVisibleTrees = (grid: Grid) => {
  let visibleCount = 0;
  grid.forEach((row, x) => {
    row.forEach((tree, y) => {
      const isVisible = getVisibility(x, y, grid);
      visibleCount += isVisible ? 1 : 0;
    });
  });
  return visibleCount;
};

// Part II
export const getBestTree = (grid: Grid) => {
  let bestTree = 0;
  grid.forEach((row, x) => {
    row.forEach((tree, y) => {
      const visibleScore = getViewingScore(x, y, grid);
      bestTree = Math.max(visibleScore, bestTree);
    });
  });
  return bestTree;
};

// Start here for both Part I and Part II to get the grid
export const getGrid = (input: string) => {
  const rows = input.split("\n");
  return rows.reduce((accum, row) => {
    const columns = [];
    for (let i = 0; i < row.length; i++) {
      columns.push(+row[i]);
    }
    accum.push(columns);
    return accum;
  }, [] as Grid);
};