From 7587f9798bfd4c2d4cf17e673643727caa329548 Mon Sep 17 00:00:00 2001
From: Sam Anthony <sam@samanthony.xyz>
Date: Wed, 1 Feb 2023 13:33:35 -0330
Subject: input handling

---
 src/lib.rs  | 21 +++++++++++++++------
 src/main.rs | 48 +++++++++++++++++++++++++++++++++++++++++++++---
 2 files changed, 60 insertions(+), 9 deletions(-)

(limited to 'src')

diff --git a/src/lib.rs b/src/lib.rs
index 527ddb8..e08796d 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,13 +1,22 @@
 pub mod ui;
 
-enum Token {
-    Operand(f64),
-    Operator(Operator),
-}
-
-enum Operator {
+pub enum Operator {
     Add,
     Sub,
     Mul,
     Div,
 }
+
+impl Operator {
+    pub fn parse(c: char) -> Result<Self, ParseOperatorError> {
+        match c {
+            '+' => Ok(Self::Add),
+            '-' => Ok(Self::Sub),
+            '*' => Ok(Self::Mul),
+            '/' => Ok(Self::Div),
+            _ => Err(ParseOperatorError(c)),
+        }
+    }
+}
+
+pub struct ParseOperatorError(char);
diff --git a/src/main.rs b/src/main.rs
index d6bf2d9..83017cb 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -7,7 +7,7 @@ use tui::{
     Frame, Terminal,
 };
 
-use pfc::ui;
+use pfc::{ui, Operator};
 
 enum Signal {
     None,
@@ -15,7 +15,10 @@ enum Signal {
 }
 
 #[derive(Default)]
-struct App {}
+struct App {
+    stack: Vec<f64>,
+    input_buffer: String,
+}
 
 impl App {
     fn handle_input(&mut self, key: KeyEvent) -> Signal {
@@ -30,6 +33,24 @@ impl App {
                 KeyCode::Char('q') => {
                     return Signal::Exit;
                 }
+                KeyCode::Char(c) => {
+                    if c.is_ascii_digit() {
+                        self.input_buffer.push(c);
+                    } else if c == '.' && !self.input_buffer.contains('.') {
+                        self.input_buffer.push(c);
+                    } else if let Ok(op) = Operator::parse(c) {
+                        self.stack.push(self.input_buffer.parse::<f64>().unwrap());
+                        self.input_buffer = String::new();
+                        self.perform_operation(op);
+                    }
+                }
+                KeyCode::Enter => {
+                    self.stack.push(self.input_buffer.parse::<f64>().unwrap());
+                    self.input_buffer = String::new();
+                }
+                KeyCode::Backspace => {
+                    self.input_buffer.pop();
+                }
                 _ => {}
             },
             _ => {}
@@ -42,7 +63,28 @@ impl App {
             .direction(Direction::Vertical)
             .constraints([Constraint::Percentage(100)].as_ref())
             .split(f.size());
-        f.render_widget(Paragraph::new("test"), chunks[0]);
+        f.render_widget(Paragraph::new(self.input_buffer.as_str()), chunks[0]);
+    }
+
+    fn perform_operation(&mut self, op: Operator) {
+        let rhs = match self.stack.pop() {
+            Some(f) => f,
+            None => {
+                return;
+            }
+        };
+        let lhs = match self.stack.pop() {
+            Some(f) => f,
+            None => {
+                return;
+            }
+        };
+        match op {
+            Operator::Add => self.stack.push(lhs + rhs),
+            Operator::Sub => self.stack.push(lhs - rhs),
+            Operator::Mul => self.stack.push(lhs * rhs),
+            Operator::Div => self.stack.push(lhs / rhs),
+        }
     }
 }
 
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