From 91b93902cb38fc630e67d7acdff70e5c817f741a Mon Sep 17 00:00:00 2001
From: Adrien Abraham <adrien.abraham.external@stormshield.eu>
Date: Fri, 6 Dec 2019 18:15:01 +0100
Subject: [PATCH] Day 5 (WIP)

---
 2019/day5.py | 86 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 86 insertions(+)
 create mode 100644 2019/day5.py

diff --git a/2019/day5.py b/2019/day5.py
new file mode 100644
index 0000000..6b00ed8
--- /dev/null
+++ b/2019/day5.py
@@ -0,0 +1,86 @@
+from enum import IntEnum
+import sys
+
+def main():
+    with open("day5.txt", "rt") as input_file:
+        codes = [int(i) for i in input_file.read().strip().split(",")]
+    last_output = run_intcode(codes)
+    print("Last output:", last_output)
+
+class Opcode(IntEnum):
+    ADD = 1
+    MUL = 2
+    IN = 3
+    OUT = 4
+    HALT = 99
+
+class ParamMode(IntEnum):
+    POS = 0
+    IMM = 1
+
+def run_intcode(codes):
+    fixed_input = 1
+    last_output = 0
+    ip = 0
+    while True:
+        code, modes = parse_code(codes[ip])
+        mode1, mode2, mode3 = modes
+        if code == Opcode.ADD:
+            print("ADD:", codes[ip : ip + 4])
+            operand1 = resolve_param(codes, ip + 1, mode1)
+            operand2 = resolve_param(codes, ip + 2, mode2)
+            output_pos = codes[ip + 3]
+            codes[output_pos] = operand1 + operand2
+            ip += 4
+        elif code == Opcode.MUL:
+            print("MUL:", codes[ip : ip + 4])
+            operand1 = resolve_param(codes, ip + 1, mode1)
+            operand2 = resolve_param(codes, ip + 2, mode2)
+            output_pos = codes[ip + 3]
+            codes[output_pos] = operand1 * operand2
+            ip += 4
+        elif code == Opcode.IN:
+            print("IN:", codes[ip : ip + 2])
+            operand_pos = codes[ip + 1]
+            codes[operand_pos] = fixed_input
+            ip += 2
+        elif code == Opcode.OUT:
+            print("OUT:", codes[ip : ip + 2])
+            operand_pos = codes[ip + 1]
+            last_output = codes[operand_pos]
+            print("\t->", last_output)
+            ip += 2
+        elif code == Opcode.HALT:
+            print("HALT.")
+            break
+        else:
+            sys.exit("Wrong opcode: {}".format(code))
+    return last_output
+
+def parse_code(code):
+    opcode = get_digit(code, 2)*10 + get_digit(code, 1)
+    if code < 100:
+        return opcode, (ParamMode.IMM,) * 3
+    mode1 = ParamMode(get_digit(code, 3))
+    mode2 = ParamMode(get_digit(code, 4))
+    mode3 = ParamMode(get_digit(code, 5))
+    return opcode, (mode1, mode2, mode3)
+
+def get_digit(value, digit):
+    digit_str = str(value)
+    if digit > len(digit_str):
+        return 0
+    try:
+        return int(digit_str[len(digit_str) - digit])
+    except IndexError:
+        return 0
+
+def resolve_param(codes, pos, mode):
+    if mode == ParamMode.POS:
+        return codes[codes[pos]]
+    elif mode == ParamMode.IMM:
+        return codes[pos]
+
+
+if __name__ == "__main__":
+    main()