#!/usr/bin/env python3
# 2023 Day 5: If You Give A Seed A Fertilizer

def process_input(filename):
    """Acquire input data"""
    with open(filename) as file:
        input = file.read().splitlines()

    seeds = []
    maps = []
    
    for line in input:
        if line == '': continue

        token = line.split()

        if token[1] == 'map:':
            maps.append([])
            map_index = len(maps) - 1
            continue

        if token[0] == 'seeds:':
            st = 1
            while st < len(token):
                seed_start = int(token[st])
                seed_end = seed_start +int(token[st+1]) - 1
                seeds.append((seed_start, seed_end))
                st += 2
            continue

        dest = int(token[0])
        source = int(token[1])
        range_len = int(token[2])
        source_end = source + range_len - 1
        adjustment = dest - source
        maps[map_index].append((source, source_end, adjustment))
    return seeds, maps

def apply_maps():
    lowest = 99999999999999999
    for seed in seeds:
        destinations = []
        destinations.append(seed)
        for map in maps:
            sources = destinations
            destinations = []
            while len(sources) > 0:
                source = sources.pop()
                source_start, source_end = source
                for range in map:
                    map_start, map_end, adjust = range
                    if source_start >= map_start and source_end <= map_end:
                        destinations.append((source_start+adjust, source_end+adjust))
                        break
                    if source_end < map_start or source_start > map_end:
                        continue
                    if source_start < map_start:
                        sources.append((source_start, map_start-1))
                        sources.append((map_start, source_end))
                        break
                    if source_end > map_end:
                        sources.append((source_start, map_end))
                        sources.append((map_end+1, source_end))
                        break
                else:
                    destinations.append(source)
        seed_lowest = lowest_location(destinations)
        lowest = min(lowest, seed_lowest)
    return lowest

def lowest_location(locations):
    lowest = locations[0][0]
    for location in locations:
        lowest = min(location[0], lowest)
    return lowest

#-----------------------------------------------------------------------------------------

filename = '5-input.txt'
#filename = 'sample.txt'

seeds, maps = process_input(filename)

lowest = apply_maps()

print()
print('Location:', lowest)