Fix opposite_eq method.

Simplify method in Simplify trait.

Fix distributive law.

Response for the simplify endpoint.

HTTP client.

camelCase and SCREAMING_SNAKE_CASE for struct and enum

src/routing/simplify.rs

@@ -1,7 +1,11 @@
-use axum::{Router, routing::get};
+use axum::{Json, Router, routing::get};
 use axum::extract::{Path, Query};
-use serde::Deserialize;
+use axum::http::StatusCode;
+use axum::response::{IntoResponse, Response};
+use serde::{Deserialize, Serialize};
 
+use crate::expressions::expression::Expression;
+use crate::expressions::simplify::Simplify;
 use crate::language::{AcceptLanguage, Language};
 
 pub fn router() -> Router<()> {
@@ -23,13 +27,32 @@ struct QueryOptions {
     lang: Language,
     #[serde(default = "default_true")]
     simplify: bool,
-    #[serde(default)]
+    #[serde(default = "default_true")]
     case_sensitive: bool,
 }
 
+#[derive(Serialize)]
+#[serde(rename_all = "camelCase")]
+struct SimplifyResponse {
+    before: String,
+    after: String,
+    order_of_operations: Vec<String>,
+    expression: Expression,
+}
+
 // TODO
-async fn simplify(Path(path): Path<String>, query: Query<QueryOptions>, accept_language: Option<AcceptLanguage>) -> String {
-    format!("Path: {}, Query: {:?}, Accept-language header: {:?}", path, query, accept_language)
+async fn simplify(Path(path): Path<String>, query: Query<QueryOptions>, accept_language: Option<AcceptLanguage>) -> Response {
+    if let Ok(expression) = Expression::try_from(path.as_str()) {
+        let simplified = expression.simplify();
+        Json(SimplifyResponse {
+            before: expression.to_string(),
+            after: simplified.to_string(),
+            order_of_operations: vec![], // TODO
+            expression: simplified,
+        }).into_response()
+    } else {
+        (StatusCode::BAD_REQUEST, "Invalid expression").into_response()
+    }
 }
 
 async fn simplify_and_table() {