grid.lua

---@module 'lib.external.class'
local class = require "lib.external.class"
---@module 'lib.safety'
local safety = require "lib.safety"
---@class Grid
local Grid = class("Grid")

--- A grid of cells
---@param width integer
---@param height integer
function Grid:initialize(width, height)
  safety.ensureIntegerOver(width, 0, "width")
  safety.ensureIntegerOver(height, 0, "height")
  self.grid = {}
  for h = 1, height do self.grid[h] = {} end
  self.width = width
  self.height = height
end

--- Sets a value of a single cell in the grid
---@param x integer
---@param y integer
---@param value any
function Grid:set(x, y, value)
  safety.ensureIntegerOver(x, 0, "x")
  safety.ensureIntegerOver(y, 0, "y")
  assert(x <= self.width, "x is out of bounds")
  assert(y <= self.height, "y is out of bounds")
  self.grid[y][x] = value
end

--- Gets a value of a single cell in the grid
---@param x integer
---@param y integer
---@return any
function Grid:get(x, y)
  safety.ensureIntegerOver(x, 0, "x")
  safety.ensureIntegerOver(y, 0, "y")
  assert(x <= self.width, "x is out of bounds")
  assert(y <= self.height, "y is out of bounds")
  return self.grid[y][x]
end

--- Extends the grid by a certain amount up, down, left, and right
---@param up integer
---@param down integer
---@param left integer
---@param right integer
function Grid:extend(up, down, left, right)
  safety.ensureIntegerOver(up, -1, "up")
  safety.ensureIntegerOver(down, -1, "down")
  safety.ensureIntegerOver(left, -1, "left")
  safety.ensureIntegerOver(right, -1, "right")
  for _ = 1, up do
    table.insert(self.grid, 1, {})
    self.height = self.height + 1
  end
  for k = self.height + 1, self.height + down do
    table.insert(self.grid, k, {})
    self.height = self.height + 1
  end
  for _ = 1, left do
    for k = 1, self.height do table.insert(self.grid[k], 1, nil) end
    self.width = self.width + 1
  end
  self.width = self.width + right
end

--- Gets the width of the grid
---@return integer
function Grid:getWidth() return self.width end

--- Gets the height of the grid
---@return integer
function Grid:getHeight() return self.height end

--- Double iterates over the grid
---@return fun():integer, integer, any
function Grid:iter()
  local y = 1
  local x = 0
  return function()
    x = x + 1
    if x > self.width then -- Reset to next row
      x = 1
      y = y + 1
    end
    if y > self.height then -- End if run out
      ---@diagnostic disable-next-line: missing-return-value, return-type-mismatch fix stupid linter
      return nil
    end
    return x, y, self.grid[y][x]
  end
end

return Grid