Permit adding a new favorite

src/database.rs

@@ -7,7 +7,7 @@ mod errors;
 
 use diesel::prelude::*;
 
-use crate::models::{InsertTitle, Title};
+use crate::models::{InsertFavorite, InsertTitle, Title};
 use crate::schema::title;
 use crate::schema::title::dsl::*;
 use errors::DatabaseError;
@@ -34,9 +34,31 @@ pub fn add_all_titles<'a>(
     Ok(())
 }
 
+/// Inserts a favorite in the local database, if a matching Title exists.
+pub fn insert_favorite(title_mirabelid: i32) -> Result<(), DatabaseError> {
+    let connection = &mut crud::establish_connection()?;
+
+    // search for a matching title
+    if crud::search_title_from_mirabelid(connection, title_mirabelid)?.is_empty() {
+        // no matching title, return an error
+        Err(DatabaseError::NotFound)
+    } else {
+        // title exists: check if the favorite already exists and insert it
+        if crud::search_favorite_from_mirabelid(connection, title_mirabelid)?.is_empty() {
+            // no favorite found, insert it
+            let new_favorite = InsertFavorite { title_mirabelid };
+            crud::create_favorite(connection, new_favorite);
+            Ok(())
+        } else {
+            // else return an error
+            Err(DatabaseError::FoundDuplicate)
+        }
+    }
+}
+
 /// Searches for a titre with a keyword and returns the found Title instances.
 pub fn search_titre(keyword: &str) -> Result<Vec<Title>, DatabaseError> {
     let connection = &mut crud::establish_connection()?;
 
-    crud::search_titre(connection, keyword)
+    crud::search_titre_from_keyword(connection, keyword)
 }

src/database/crud.rs

@@ -6,7 +6,9 @@ use diesel::pg::PgConnection;
 use diesel::prelude::*;
 use dotenvy::dotenv;
 
-use crate::models::{InsertTitle, Title};
+use crate::models::{Favorite, InsertFavorite, InsertTitle, Title};
+use crate::schema::favorite;
+use crate::schema::favorite::dsl::*;
 use crate::schema::title;
 use crate::schema::title::dsl::*;
 
@@ -20,6 +22,18 @@ pub(super) fn establish_connection() -> Result<PgConnection, DatabaseError> {
     Ok(PgConnection::establish(&database_url)?)
 }
 
+/// Inserts a new favorite in the favorite table and returns the inserted item.
+pub(super) fn create_favorite(
+    connection: &mut PgConnection,
+    new_favorite: InsertFavorite,
+) -> QueryResult<Favorite> {
+    let result = diesel::insert_into(favorite::table)
+        .values(new_favorite)
+        .get_result(connection)?;
+
+    Ok(result)
+}
+
 /// Inserts a new title in the title table and returns the inserted item.
 pub(super) fn create_title(
     connection: &mut PgConnection,
@@ -32,8 +46,32 @@ pub(super) fn create_title(
     Ok(result)
 }
 
+/// Searches the title table for a 'mirabelid', and returns a vector of Title items.
+pub(super) fn search_title_from_mirabelid(
+    connection: &mut PgConnection,
+    search_mirabelid: i32,
+) -> Result<Vec<Title>, DatabaseError> {
+    let results = title::table
+        .filter(mirabelid.eq(search_mirabelid))
+        .load::<Title>(connection)?;
+
+    Ok(results)
+}
+
+/// Searches the favorite table for a 'mirabelid', and returns a vector of Favorite items.
+pub(super) fn search_favorite_from_mirabelid(
+    connection: &mut PgConnection,
+    search_mirabelid: i32,
+) -> Result<Vec<Favorite>, DatabaseError> {
+    let results = favorite::table
+        .filter(title_mirabelid.eq(search_mirabelid))
+        .load::<Favorite>(connection)?;
+
+    Ok(results)
+}
+
 /// Searches the title table for a 'titre', and returns a vector of Title items.
-pub(super) fn search_titre(
+pub(super) fn search_titre_from_keyword(
     connection: &mut PgConnection,
     keyword: &str,
 ) -> Result<Vec<Title>, DatabaseError> {

src/database/errors.rs

@@ -10,6 +10,8 @@ pub enum DatabaseError {
     DieselConnectionError(diesel::ConnectionError),
     DieselResultError(diesel::result::Error),
     EnvVarError(env::VarError),
+    NotFound,
+    FoundDuplicate,
 }
 
 /// The Display trait is needed to print these errors.
@@ -19,6 +21,8 @@ impl Display for DatabaseError {
             DatabaseError::DieselConnectionError(err) => write!(f, "{}", err),
             DatabaseError::DieselResultError(err) => write!(f, "{}", err),
             DatabaseError::EnvVarError(err) => write!(f, "{}", err),
+            DatabaseError::NotFound => write!(f, "Item was not found"),
+            DatabaseError::FoundDuplicate => write!(f, "Item is already present"),
         }
     }
 }