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

local function part1(ranges, ids)
    local fresh = 0
    local counted = {}
    for _, id in ipairs(ids) do
        for _, range in ipairs(ranges) do
            if id >= range[1] and id <= range[2] and counted[id] == nil then
                fresh = fresh + 1
                counted[id] = true
            end
        end
    end
    return fresh
end

local function merge_ranges(r1, r2)
    local do_overlap = r1[1] <= r2[2] and r1[2] >= r2[1]
    if do_overlap then
        return true, {
            math.min(r1[1], r2[1]),
            math.max(r1[2], r2[2])
        }
    else
        return false, nil
    end
end

local function part2(ranges)
    table.sort(ranges, function(l, r)
        if l[1] == r[1] then
            return l[2] < r[2]
        else
            return l[1] < r[1]
        end
    end)
    local total = 0
    local final_ranges = {}
    for _, r1 in ipairs(ranges) do
        if #final_ranges == 0 then
            table.insert(final_ranges, r1)
        else
            local did_merge, merged = merge_ranges(r1, final_ranges[#final_ranges])
            if did_merge then
                final_ranges[#final_ranges] = merged
            else
                table.insert(final_ranges, r1)
            end
        end
    end

    for _, range in ipairs(final_ranges) do
        total = total + (range[2] - range[1] + 1)
    end
    return total
end

---@param input string
local function parse_input(input)
    local ranges = {}
    local ids = {}
    local lines = helper.line_iter(input)
    for line in lines do
        if not line:match("-") then
            table.insert(ids, tonumber(line))
        else
            local num_iter = line:gmatch("%d+")
            table.insert(ranges, { tonumber(num_iter()), tonumber(num_iter()) })
        end
    end
    return ranges, ids
end

local input = helper.get_input(5, 2025)
local sample = helper.get_sample("sample.txt")

local ranges, ids = parse_input(input)
print(part1(ranges, ids))
print(string.format("%.f", part2(ranges)))