7 files changed, 2173 insertions, 17 deletions

diff --git a/aoc/__main__.py b/aoc/__main__.py
index 337bdfe..e1b2a85 100644
--- a/aoc/__main__.py
+++ b/aoc/__main__.py
@@ -2,8 +2,10 @@
 import argparse
 import importlib
 import os
+from pathlib import Path
+from shutil import copytree
 from time import perf_counter
-from typing import List
+from typing import List, Callable
 
 
 def day(assignment_part: str) -> str:
@@ -17,8 +19,41 @@ def kwargs(kwarg: str) -> List:
     return kwarg.split("=")
 
 
+def run(args: argparse.Namespace):
+    assignment_day = importlib.import_module(args.day)
+
+    Assignment = getattr(assignment_day, f"Assignment{args.part}")
+    assignment = Assignment(
+        path=os.path.dirname(assignment_day.__file__), **dict(args.kwargs)
+    )
+
+    start = perf_counter()
+    print(
+        assignment.run(
+            input=assignment.read_input(example=args.example),
+        )
+    )
+    end = perf_counter()
+    delta = end - start
+    print()
+    print(f'{(delta if delta > 1 else delta * 1000):.3f}{"s" if delta > 1 else "ms"}')
+
+
+def new(args: argparse.Namespace):
+    self = importlib.import_module(".", package="aoc")
+    path = Path(self.__file__)
+    template = path.parent.joinpath("template")
+    target = path.parent.parent.joinpath(args.day)
+
+    try:
+        copytree(template, target)
+    except FileExistsError:
+        print(f"{args.day} already exists")
+
+
 parser = argparse.ArgumentParser(description="Advent of Code")
 
+parser.add_argument("command", type=str, choices=["run", "new"])
 parser.add_argument("day", type=str, help="Assignment day")
 parser.add_argument(
     "-p",
@@ -34,20 +69,9 @@ parser.add_argument("kwargs", type=kwargs, nargs="*")
 
 if __name__ == "__main__":
     args = parser.parse_args()
-    assignment_day = importlib.import_module(args.day)
-
-    Assignment = getattr(assignment_day, f"Assignment{args.part}")
-    assignment = Assignment(
-        path=os.path.dirname(assignment_day.__file__), **dict(args.kwargs)
-    )
 
-    start = perf_counter()
-    print(
-        assignment.run(
-            input=assignment.read_input(example=args.example),
-        )
-    )
-    end = perf_counter()
-    delta = end - start
-    print()
-    print(f'{(delta if delta > 1 else delta * 1000):.3f}{"s" if delta > 1 else "ms"}')
+    match args.command:
+        case "run":
+            run(args)
+        case "new":
+            new(args)
diff --git a/aoc/template/__init__.py b/aoc/template/__init__.py
new file mode 100644
index 0000000..05b2b45
--- /dev/null
+++ b/aoc/template/__init__.py
@@ -0,0 +1,16 @@
+# -*- coding: utf-8 -*-
+from abc import ABC
+
+from aoc import BaseAssignment
+
+
+class Assignment(BaseAssignment, ABC):
+    pass
+
+
+class AssignmentOne(Assignment):
+    pass
+
+
+class AssignmentTwo(Assignment):
+    pass
diff --git a/aoc/template/example.txt b/aoc/template/example.txt
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/aoc/template/example.txt
diff --git a/aoc/template/input.txt b/aoc/template/input.txt
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/aoc/template/input.txt
diff --git a/day9/__init__.py b/day9/__init__.py
new file mode 100644
index 0000000..afa44aa
--- /dev/null
+++ b/day9/__init__.py
@@ -0,0 +1,108 @@
+# -*- coding: utf-8 -*-
+from abc import ABC
+from copy import copy
+from dataclasses import dataclass
+from typing import Tuple, Iterator, List
+
+from aoc import BaseAssignment
+
+
+@dataclass
+class Coordinate:
+    x: int
+    y: int
+
+    def __hash__(self):
+        return tuple([self.x, self.y]).__hash__()
+
+    def __sub__(self, other: "Coordinate"):
+        return Coordinate(self.x - other.x, self.y - other.y)
+
+    @property
+    def polarity_x(self):
+        try:
+            return abs(self.x) / self.x
+        except ZeroDivisionError:
+            return 0
+
+    @property
+    def polarity_y(self):
+        try:
+            return abs(self.y) / self.y
+        except ZeroDivisionError:
+            return 0
+
+
+class Assignment(BaseAssignment, ABC):
+    def parse_line(self, item: str) -> Tuple[str, int]:
+        direction, amount = item.split(" ")
+        return direction, int(amount)
+
+    def move(self, direction: str, amount: int):
+        pass
+
+    @staticmethod
+    def next_head(head: Coordinate, direction: str):
+        match direction:
+            case "R":
+                head.x += 1
+            case "L":
+                head.x -= 1
+            case "U":
+                head.y += 1
+            case "D":
+                head.y -= 1
+
+    @staticmethod
+    def next_tail(head: Coordinate, tail: Coordinate):
+        delta = head - tail
+
+        if abs(delta.x) > 1 and delta.y == 0:
+            tail.x += delta.x - delta.polarity_x
+        if abs(delta.x) > 1 and abs(delta.y) == 1:
+            tail.x += delta.x - delta.polarity_x
+            tail.y += delta.y
+        if abs(delta.y > 1) and delta.x == 0:
+            tail.y += delta.y - delta.polarity_y
+        if abs(delta.y) > 1 and abs(delta.x) == 1:
+            tail.y += delta.y - delta.polarity_y
+            tail.x += delta.x
+
+    def tail_positions(self, input: Iterator[str]) -> Iterator[Coordinate]:
+        head = Coordinate(0, 0)
+        tail = Coordinate(0, 0)
+
+        for line in input:
+            direction, amount = self.parse_line(line)
+
+            for _ in range(amount):
+                self.next_head(head, direction)
+                self.next_tail(head, tail)
+                yield tail
+
+
+class AssignmentOne(Assignment):
+    example_result = 13
+
+    def run(self, input: Iterator) -> int:
+        unique_tail_positions = set()
+
+        for position in self.tail_positions(input):
+            unique_tail_positions.add(copy(position))
+
+        print(unique_tail_positions)
+
+        for y in range(5):
+            items = []
+            for x in range(6):
+                if Coordinate(x, y) in unique_tail_positions:
+                    items.append("#")
+                else:
+                    items.append(".")
+            print("".join(items))
+
+        return len(unique_tail_positions)
+
+
+class AssignmentTwo(Assignment):
+    pass
diff --git a/day9/example.txt b/day9/example.txt
new file mode 100644
index 0000000..9874df2
--- /dev/null
+++ b/day9/example.txt
@@ -0,0 +1,8 @@
+R 4
+U 4
+L 3
+D 1
+R 4
+D 1
+L 5
+R 2
diff --git a/day9/input.txt b/day9/input.txt
new file mode 100644
index 0000000..3da93c3
--- /dev/null
+++ b/day9/input.txt
@@ -0,0 +1,2000 @@
+L 2
+U 2
+L 1
+D 1
+U 1
+L 2
+R 2
+D 1
+U 2
+D 1
+R 2
+U 1
+L 2
+D 2
+L 2
+R 2