Overengineer the intcode computer

src/day2.rs

@@ -1,25 +1,70 @@
 use std;
 
+struct Params {
+    op1: usize,
+    op2: usize,
+    result: usize,
+}
+
+enum Instruction {
+    Add(Params),
+    Mul(Params),
+    GetParam(usize),
+    Start,
+    Halt,
+}
+
+struct IntcodeComputer {
+    memory: Vec<usize>,
+    output: Vec<usize>,
+    instruction: Instruction,
+    ip: usize, // instruction pointer
+}
+
+impl IntcodeComputer {
+    fn new(memory: Vec<usize>) -> Self {
+	IntcodeComputer {
+	    memory,
+	    output: vec![],
+	    instruction: Instruction::Start,
+	    ip: 0,
+	}
+    }
+    fn add(&mut self) {
+        let op = self.get_params();
+        self.memory[op.result] = self.memory[op.op1] + self.memory[op.op2]
+    }
+    fn mul(&mut self) {
+        let op = self.get_params();
+        self.memory[op.result] = self.memory[op.op1] * self.memory[op.op2]
+    }
+    fn get_params(&mut self) -> Params {
+        Params {
+            op1: self.next(),
+            op2: self.next(),
+            result: self.next(),
+        }
+    }
+    fn halt(&mut self) {
+        self.instruction = Instruction::Halt;
+    }
+    fn next(&mut self) -> usize {
+        self.ip += 1;
+        self.memory[self.ip]
+    }
+    fn tick(&mut self) {
+        match self.next() {
+            1 => self.add(),
+            2 => self.mul(),
+            99 => self.halt(),
+            _ => panic!("invalid input code"),
+        }
+    }
+}
+
 fn compute_intcode(p: &mut Vec<usize>) -> Vec<usize> {
-    for idx in (0..(p.len())).step_by(4) {
+    let computer = IntcodeComputer::new(p); 
-        match p[idx] {
+    while 
-            1 => {
-                let left = p[idx + 1];
-                let right = p[idx + 2];
-                let res = p[idx + 3];
-                p[res] = p[left] + p[right];
-            }
-            2 => {
-                let left = p[idx + 1];
-                let right = p[idx + 2];
-                let res = p[idx + 3];
-                p[res] = p[left] * p[right];
-            }
-            99 => break,
-            _ => panic!("Something went wrong!"),
-        }
-    }
-    p.to_vec()
 }
 
 pub fn part_one() {