use helper traits for better code

3 files changed, 38 insertions, 6 deletions

diff --git a/src/api/mod.rs b/src/api/mod.rs
index 9c771fd..c33e6ba 100644
--- a/src/api/mod.rs
+++ b/src/api/mod.rs
@@ -16,7 +16,7 @@ pub use self::{
 
 use image::DynamicImage;
 use itertools::Itertools;
-use reqwest::{Client, Url};
+use reqwest::{Client, StatusCode, Url};
 use serde::{de::DeserializeOwned, Serialize};
 use std::path::Path;
 
@@ -28,6 +28,7 @@ const BASE_URL: &str = "https://api.guildwars2.com/v2/";
 quick_error! {
     #[derive(Debug)]
     pub enum ApiError {
+        ItemNotFound {}
         SerializationError(err: serde_json::Error) {
             cause(err)
             from()
@@ -47,6 +48,23 @@ quick_error! {
     }
 }
 
+trait ApiResponse
+where
+    Self: Sized,
+{
+    fn ensure_found(self) -> Result<Self, ApiError>;
+}
+
+impl ApiResponse for reqwest::Response {
+    fn ensure_found(self) -> Result<Self, ApiError> {
+        if self.status() == StatusCode::PARTIAL_CONTENT || self.status() == StatusCode::NOT_FOUND {
+            Err(ApiError::ItemNotFound)
+        } else {
+            Ok(self)
+        }
+    }
+}
+
 /// Trait for API objects that have an ID.
 ///
 /// This is used by [`Api`](struct.Api.html) to properly retrieve and cache objects.
@@ -143,6 +161,7 @@ impl Api {
             .get(url)
             .query(&[("ids", api_arg)])
             .send()?
+            .ensure_found()?
             .json()?;
         for result in &resp {
             let cache_path = format!("{}{}", cache_prefix, result.get_id().to_string());
diff --git a/src/bt.rs b/src/bt.rs
index aac8484..21078ff 100644
--- a/src/bt.rs
+++ b/src/bt.rs
@@ -112,7 +112,7 @@ pub enum Legend {
 }
 
 impl Legend {
-    pub fn get_api_id(self) -> Option<String> {
+    pub fn api_id(self) -> Option<String> {
         Some(
             match self {
                 Legend::None => return None,
diff --git a/src/main.rs b/src/main.rs
index d3839b2..181d64a 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -83,6 +83,19 @@ impl StdError for NotFound {}
 /// 2. We don't want yet another error kind with a lot of kinds.
 type MainResult<T> = Result<T, Box<dyn StdError>>;
 
+/// A trait for containers that only contain a single item.
+trait SingleContainer<T> {
+    /// Extract the single element by consuming the container.
+    fn single(self) -> T;
+}
+
+impl<T> SingleContainer<T> for Vec<T> {
+    fn single(self) -> T {
+        assert_eq!(self.len(), 1, "this container must have exactly 1 element.");
+        self.into_iter().next().unwrap()
+    }
+}
+
 /// Find the profession by the given name.
 fn find_profession(api: &mut Api, name: &str) -> MainResult<Profession> {
     let profession_ids = api.get_profession_ids()?;
@@ -93,7 +106,7 @@ fn find_profession(api: &mut Api, name: &str) -> MainResult<Profession> {
         .ok_or_else(|| NotFound::Profession(name.to_owned()))?
         .clone();
 
-    Ok(api.get_professions(&[profession_id])?.remove(0))
+    Ok(api.get_professions(&[profession_id])?.single())
 }
 
 /// Resolve a skill.
@@ -106,7 +119,7 @@ fn resolve_skill(api: &mut Api, profession: &Profession, text: &str) -> MainResu
     if let Ok(num_id) = numeric {
         let exists = profession.skills.iter().any(|s| s.id == num_id);
         if exists {
-            return Ok(api.get_skills(&[num_id])?.remove(0));
+            return Ok(api.get_skills(&[num_id])?.single());
         } else {
             return Err(NotFound::SkillId(num_id).into());
         }
@@ -191,10 +204,10 @@ fn run_searching(api: &mut Api, matches: &ArgMatches) -> MainResult<BuildTemplat
             .map(|s| resolve_skill(api, &profession, s))
             .collect::<Result<Vec<_>, _>>()?
     } else if let Some(l) = legends.first() {
-        let l = api.get_legends(&[l.get_api_id().unwrap()])?.remove(0);
+        let l = api.get_legends(&[l.api_id().unwrap()])?.single();
         let mut result = Vec::new();
         for skill_id in (&[l.heal]).iter().chain(&l.utilities).chain(&[l.elite]) {
-            let skill = api.get_skills(&[*skill_id])?.remove(0);
+            let skill = api.get_skills(&[*skill_id])?.single();
             result.push(skill);
         }
         result