From 809bcb641b82cdc22623f8d6a4e3c5d7dc5bcd7b Mon Sep 17 00:00:00 2001
From: Jeff Baskin <jeff.l.baskin@gmail.com>
Date: Mon, 16 Jan 2023 12:07:33 -0500
Subject: [PATCH] Added an entry point to the database.

---
 src/morethantext/cachetype.rs |  4 +--
 src/morethantext/mod.rs       | 47 +++++++++++++++++++++++++++++++++--
 2 files changed, 47 insertions(+), 4 deletions(-)

diff --git a/src/morethantext/cachetype.rs b/src/morethantext/cachetype.rs
index a11b084..9b68078 100644
--- a/src/morethantext/cachetype.rs
+++ b/src/morethantext/cachetype.rs
@@ -5,7 +5,7 @@ use std::{collections::HashMap, fmt, str};
 pub struct Databases;
 
 impl Databases {
-    fn new() -> Self {
+    pub fn new() -> Self {
         Self {}
     }
 }
@@ -17,7 +17,7 @@ pub enum CacheType {
 }
 
 impl CacheType {
-    fn entry_type(&self) -> String {
+    pub fn entry_type(&self) -> String {
         match self {
             CacheType::Raw(_) => "Raw".to_string(),
             CacheType::DBMap(_) => "DBMap".to_string(),
diff --git a/src/morethantext/mod.rs b/src/morethantext/mod.rs
index c6e6914..855ad2b 100644
--- a/src/morethantext/mod.rs
+++ b/src/morethantext/mod.rs
@@ -7,7 +7,7 @@ use async_std::{
     sync::{Arc, Mutex},
     task::{sleep, spawn},
 };
-use cachetype::CacheType;
+use cachetype::{CacheType, Databases};
 use error::DBError;
 use rand::{distributions::Alphanumeric, thread_rng, Rng};
 use std::{
@@ -17,6 +17,7 @@ use std::{
 };
 
 const DATA: &str = "data";
+const ENTRY: &str = "databases";
 
 #[derive(Clone)]
 struct CacheEntry {
@@ -56,6 +57,7 @@ impl fmt::Display for CacheEntry {
 pub struct MoreThanText {
     cache: Arc<Mutex<HashMap<String, CacheEntry>>>,
     dir: String,
+    entry: String,
 }
 
 impl MoreThanText {
@@ -71,10 +73,24 @@ impl MoreThanText {
                 }
             }
         }
-        let output = Self {
+        let mut output = Self {
             cache: Arc::new(Mutex::new(HashMap::new())),
             dir: data_dir.to_str().unwrap().to_string(),
+            entry: "undeclared".to_string(),
         };
+        let entry_file = Path::new(dir).join(ENTRY);
+        let id: String;
+        if entry_file.is_file().await {
+            let holder = read(entry_file).await.unwrap();
+            id = str::from_utf8(&holder).unwrap().to_string();
+        } else {
+            id = output
+                .add_entry(CacheType::DBMap(Databases::new()))
+                .await
+                .unwrap();
+            write(entry_file, id.as_bytes()).await.unwrap();
+        }
+        output.entry = id;
         let looper = output.cache.clone();
         spawn(async move {
             let hold_time = Duration::from_secs(300);
@@ -239,6 +255,33 @@ mod init {
             }
         };
     }
+
+    #[async_std::test]
+    async fn creates_entry_point() {
+        let dir = tempdir().unwrap();
+        let db = MoreThanText::new(dir.path().to_str().unwrap())
+            .await
+            .unwrap();
+        let entry = dir.path().join(ENTRY);
+        assert!(entry.is_file(), "Did not create entry point file.");
+        let data = read(entry).await.unwrap();
+        let id = str::from_utf8(&data).unwrap();
+        let cache = db.get_entry(&id).await.unwrap();
+        assert_eq!(cache.data.entry_type(), "DBMap");
+        assert_eq!(db.entry, id);
+    }
+
+    #[async_std::test]
+    async fn use_existing_entry_point() {
+        let dir = tempdir().unwrap();
+        let db1 = MoreThanText::new(dir.path().to_str().unwrap())
+            .await
+            .unwrap();
+        let db2 = MoreThanText::new(dir.path().to_str().unwrap())
+            .await
+            .unwrap();
+        assert_eq!(db1.entry, db2.entry, "Did not read existing entry.");
+    }
 }
 
 #[cfg(test)]