From 6ed821e4b84fe4fa11a843c5ab4fa16cbcbbe529 Mon Sep 17 00:00:00 2001
From: Jeff Baskin <jeff.l.baskin@gmail.com>
Date: Tue, 12 Jul 2022 16:55:20 -0400
Subject: [PATCH] Began building database engine seperate from query language.

---
 src/database/database.rs | 130 +++++++++++++++++++++++++++++++++++++++
 src/database/mod.rs      |   2 +
 2 files changed, 132 insertions(+)
 create mode 100644 src/database/database.rs

diff --git a/src/database/database.rs b/src/database/database.rs
new file mode 100644
index 0000000..c6c403a
--- /dev/null
+++ b/src/database/database.rs
@@ -0,0 +1,130 @@
+use async_std::sync::{Arc, RwLock};
+use std::{collections::HashMap, fmt, str::FromStr};
+
+#[derive(Clone, PartialEq)]
+pub enum Field {
+    Table,
+}
+
+impl fmt::Display for Field {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        match self {
+            Field::Table => write!(f, "table"),
+        }
+    }
+}
+
+impl FromStr for Field {
+    type Err = ();
+    fn from_str(input: &str) -> Result<Field, Self::Err> {
+        match input {
+            "table" => Ok(Field::Table),
+            _ => Err(()),
+        }
+    }
+}
+
+pub struct Table {
+    fields: Arc<RwLock<HashMap<String, Field>>>,
+}
+
+impl Table {
+    pub async fn new() -> Self {
+        Self {
+            fields: Arc::new(RwLock::new(HashMap::new())),
+        }
+    }
+
+    pub async fn add_field(&self, name: &str, ftype: &str) {
+        let mut fmap = self.fields.write().await;
+        fmap.insert(name.to_string(), Field::from_str(ftype).unwrap());
+    }
+
+    pub async fn fields(&self) -> HashMap<String, Field> {
+        let fmap = self.fields.read().await;
+        fmap.clone()
+    }
+}
+
+pub struct Database;
+
+impl Database {
+    pub async fn new() -> Self {
+        Self {}
+    }
+
+    pub async fn add_table(&self, _name: String) -> Table {
+        Table::new().await
+    }
+}
+
+#[cfg(test)]
+mod tables {
+    use super::*;
+
+    #[async_std::test]
+    async fn new_table() {
+        Table::new().await;
+    }
+
+    #[async_std::test]
+    async fn add_field() {
+        let table = Table::new().await;
+        let mut expected: HashMap<String, Field> =  HashMap::new();
+        expected.insert("stan".to_string(), Field::Table);
+        expected.insert("lee".to_string(), Field::Table);
+        table.add_field("stan", "table").await;
+        table.add_field("lee", "table").await;
+        let output = table.fields().await;
+        assert!(output == expected, "Table did not get the fields added.");
+    }
+}
+
+#[cfg(test)]
+mod databases {
+    use super::*;
+
+    #[async_std::test]
+    async fn new_database() {
+        Database::new().await;
+    }
+
+    #[async_std::test]
+    async fn add_table() {
+        let db = Database::new().await;
+        db.add_table("fred".to_string()).await;
+    }
+}
+
+#[cfg(test)]
+mod fields {
+    use super::*;
+
+    fn get_field_map() -> HashMap<String, Field> {
+        let mut fields: HashMap<String, Field> = HashMap::new();
+        fields.insert("table".to_string(), Field::Table);
+        return fields;
+    }
+
+    #[test]
+    fn convert_to_string() {
+        for (key, value) in get_field_map().iter() {
+            assert!(key == &value.to_string(), "\n\nGot:  {}\nWant: {}\n\n", value.to_string(), key);
+        }
+    }
+
+    #[test]
+    fn convert_from_string() {
+        for (key, value) in get_field_map().iter() {
+            assert!(&Field::from_str(key).unwrap() == value, "\n\nDid not return a Field::{}", key);
+        }
+    }
+
+    #[test]
+    fn convert_from_string_error() -> Result<(), String> {
+        match Field::from_str("jkljkl") {
+            Ok(_) => Err("Field jkljkl should not exist.".to_string()),
+            Err(_) => Ok(()),
+        }
+    }
+}
diff --git a/src/database/mod.rs b/src/database/mod.rs
index 53e3016..67ea004 100644
--- a/src/database/mod.rs
+++ b/src/database/mod.rs
@@ -2,6 +2,8 @@ use async_graphql::{Context, EmptySubscription, Error, Object, Result, Schema};
 use async_std::sync::RwLock;
 use serde_json;
 
+mod database;
+
 #[derive(Clone)]
 struct Table {
     name: String,