Lua Minesweeper

-- Made for the use with NotSoBot.

local Grid, Counters = {}, {
    ":one:", ":two:",
    ":three:", ":four:",
    ":five:", ":six:",
    ":seven:", ":eight:",
}

local Rows = math.max(1, tonumber("{arg:0}") or 10)
local Columns = math.max(1, tonumber("{arg:1}") or 10)
local MineChance = math.max(0, math.min(tonumber("{arg:2}") or 20, 100)) * 0.01

function Grid:Create()
    if (Rows * Columns < 9) then
        return "Grid is too small. There needs to be at least 9 tiles."
    end

    for r = 1, Rows do
        local row = {}

        for c = 1, Columns do
            table.insert(row, ":white_large_square:")
        end

        table.insert(self, row)
    end

    self:ScatterMines()
    self:CountMines()

    return self:Format()
end

function Grid:ScatterMines()
    math.randomseed(os.time())

    local mines = 0

    for r, row in ipairs(self) do
        for c, square in ipairs(row) do
            if (math.random() <= MineChance) then
                row[c] = ":bomb:"
                mines = mines + 1
            end
        end
    end

    if (MineChance > 0 and mines == 0) then
        local r = self[math.random(Rows)]
        local c = math.random(Columns)

        r[c] = ":bomb:"
    end
end

function Grid:CountMines()
    for r, row in ipairs(self) do
        for c, s in ipairs(row) do
            if (s ~= ":bomb:") then
                local mines = 0

                for x = -1, 1 do
                    for y = -1, 1 do
                        local r = self[r + x]

                        if (r and r[c + y] == ":bomb:") then
                            mines = mines + 1
                        end
                    end
                end

                if (mines > 0) then
                    row[c] = Counters[mines]
                end
            end
        end
    end
end

function Grid:Format()
    local grid = {}

    for i, r in ipairs(self) do
        r = table.concat(r, "\124\124\124\124")
        table.insert(grid, string.format("\124\124%s\124\124", r))
    end

    grid = table.concat(grid, "\n")

    return #grid > 2000 and "Grid is too large. 2,000 character limit met." or grid
end

print(Grid:Create())