package.path = package.path .. ";../lib/?.lua"
local helper = require("helper")
helper.load_lib("../lib/libaoc.so")


local function apply_op(arr, op)
    local ret
    if op == "*" then
        ret = 1
        for _, n in ipairs(arr) do
            ret = ret * n
        end
    else
        ret = 0
        for _, n in ipairs(arr) do
            ret = ret + n
        end
    end
    return ret
end

local function part1(input)
    local ret = 0
    local input_lines = helper.line_iter(input)
    local ops = {}
    for line in input_lines do
        local num_got = false
        local i = 1 -- the index of the list in ops
        local init = (#ops == 0)
        for val in line:gmatch("%d+") do
            num_got = true
            if init then -- first line of numbers
                local add = { tonumber(val) }
                table.insert(ops, add)
            else -- just appending
                table.insert(ops[i], tonumber(val))
                i = i + 1
            end
        end
        if not num_got then -- regex missed so these are the operators
            for op in line:gmatch("%S+") do
                ret = ret + apply_op(ops[i], op)
                i = i + 1
            end
        end
    end
    return ret
end


local function part2(input)
    local ret = 0
    local split_input = {}
    local max_len = 0
    for line in helper.line_iter(input) do
        local split_line = {}
        for c in line:gmatch(".") do
            table.insert(split_line, c)
        end
        if #split_line > max_len then
            max_len = #split_line
        end
        table.insert(split_input, split_line)
    end
    local nums = {}
    local op = ""
    for char_index = 1, max_len do
        local all_empty = true
        local curr_num = ""
        for _, arr in ipairs(split_input) do
            local c = arr[char_index]
            if c == " " or c == nil then
                goto continue
            end
            if c == "+" or c == "*" then
                op = c
            else -- c is a number
                curr_num = curr_num .. c
                all_empty = false
            end
            ::continue::
        end
        if all_empty then
            for i, _ in ipairs(nums) do
                nums[i] = tonumber(nums[i])
            end
            ret = ret + apply_op(nums, op)
            nums = {}
            op = ""
        else
            table.insert(nums, curr_num)
        end
    end
    return ret + apply_op(nums, op)
end


local sample = helper.get_sample("sample.txt")
local input = helper.get_input(6, 2025)

print(part1(sample))
print(part2(input))