db&adapter, add sqlx + schema & add adapter

Adds SQLX for database management, and an Adapter interface for
interacting with it. Through the type "AdapterPool"

Creates an initial_schema with everything I think I'll need.

koucha/.gitignore

@@ -1 +1,2 @@
+*.db
 /target

koucha/Cargo.toml

@@ -5,4 +5,5 @@ edition = "2024"
 
 [dependencies]
 tokio = { version = "1.49.0", features = ["full"] }
+sqlx = { version = "0.8.6", features = [ "runtime-tokio", "sqlite" ] }
 chrono = "0.4.43"

koucha/migrations/20260115003047_initial_schema.sql

@@ -0,0 +1,62 @@
+-- Add migration script here
+
+PRAGMA foreign_keys = ON;
+
+CREATE TABLE users (
+  id INTEGER PRIMARY KEY,
+  name TEXT UNIQUE NOT NULL
+);
+
+CREATE TABLE channels (
+  id INTEGER PRIMARY KEY,
+  title TEXT NOT NULL,
+  link TEXT UNIQUE NOT NULL,
+  description TEXT,
+  last_fetched TEXT
+);
+
+CREATE TABLE items (
+  id INTEGER PRIMARY KEY,
+  channel_id INTEGER NOT NULL,
+  guid TEXT NOT NULL,
+
+  fetched_at TEXT,
+  title TEXT,
+  description TEXT,
+  content TEXT,
+
+  UNIQUE(channel_id, guid),
+  FOREIGN KEY (channel_id) REFERENCES channels(id)
+);
+
+CREATE TABLE feeds (
+  id INTEGER PRIMARY KEY,
+  user_id INTEGER NOT NULL,
+  title TEXT NOT NULL,
+  FOREIGN KEY (user_id) REFERENCES users(id)
+);
+
+CREATE TABLE feed_channels (
+  feed_id INTEGER NOT NULL,
+  channel_id INTEGER NOT NULL,
+  initial_score INTEGER,
+  gravity INTEGER,
+  boost INTEGER,
+  PRIMARY KEY (feed_id, channel_id),
+  FOREIGN KEY (feed_id) REFERENCES feeds(id),
+  FOREIGN KEY (channel_id) REFERENCES channels(id)
+);
+
+CREATE TABLE feed_items (
+  item_id INTEGER NOT NULL,
+  feed_id INTEGER NOT NULL,
+  score INTEGER NOT NULL,
+  last_updated TEXT NOT NULL,
+  boosted_at TEXT,
+  archived BOOLEAN DEFAULT FALSE,
+  PRIMARY KEY (item_id, feed_id),
+  FOREIGN KEY (feed_id) REFERENCES feeds(id),
+  FOREIGN KEY (item_id) REFERENCES items(id)
+);
+CREATE INDEX idx_feed_items_score
+ON feed_items(feed_id, archived, score DESC);

koucha/src/lib.rs

@@ -3,3 +3,36 @@ use std::error::Error;
 type Result<T> = std::result::Result<T, Box<dyn Error>>;
 
 pub mod score;
+pub struct AdapterPool(sqlx::SqlitePool);
+pub struct AdapterBuilder {
+  database_url: String,
+}
+
+impl AdapterBuilder {
+  pub fn new() -> Self {
+    Self {
+      database_url: "sqlite:test.db".to_string(),
+    }
+  }
+
+  pub fn database_url(mut self, url: &str) -> Self {
+    self.database_url = url.to_string();
+    self
+  }
+
+  pub async fn create(self) -> Result<Adapter> {
+    let db = sqlx::sqlite::SqlitePoolOptions::new()
+      .connect(&self.database_url).await?;
+    sqlx::migrate!().run(&db).await?;
+
+    Ok(Adapter { db: AdapterPool(db) })
+  }
+}
+
+pub struct Adapter {
+  db: AdapterPool,
+}
+
+impl Adapter {
+  pub fn get_pool(&self) -> &AdapterPool { &self.db }
+}