feat(storage): 实现 Storage 主结构和初始化

src/storage/mod.rs

@@ -3,3 +3,90 @@ pub mod session;
 pub mod message;
 
 pub use error::StorageError;
+
+use sqlx::{Pool, Sqlite, SqlitePool};
+use std::path::Path;
+
+pub struct Storage {
+    pool: Pool<Sqlite>,
+}
+
+impl Storage {
+    /// 打开或创建数据库
+    pub async fn new(db_path: &Path) -> Result<Self, StorageError> {
+        let database_url = format!("sqlite:{}?mode=rwc", db_path.display());
+        let pool = SqlitePool::connect(&database_url).await?;
+
+        let storage = Self { pool };
+        storage.init_schema().await?;
+        Ok(storage)
+    }
+
+    /// 初始化数据库 schema
+    async fn init_schema(&self) -> Result<(), StorageError> {
+        sqlx::query(
+            r#"
+            CREATE TABLE IF NOT EXISTS sessions (
+                id              TEXT PRIMARY KEY,
+                channel        TEXT NOT NULL,
+                chat_id        TEXT NOT NULL,
+                dialog_id      TEXT NOT NULL,
+                title          TEXT NOT NULL DEFAULT '新对话',
+                created_at     INTEGER NOT NULL,
+                last_active_at INTEGER NOT NULL,
+                message_count  INTEGER DEFAULT 0,
+                routing_info   TEXT,
+                deleted_at     INTEGER,
+                UNIQUE(channel, chat_id, dialog_id)
+            )
+            "#,
+        )
+        .execute(&self.pool)
+        .await?;
+
+        sqlx::query(
+            r#"
+            CREATE INDEX IF NOT EXISTS idx_sessions_chat
+            ON sessions(channel, chat_id, deleted_at)
+            "#,
+        )
+        .execute(&self.pool)
+        .await?;
+
+        sqlx::query(
+            r#"
+            CREATE TABLE IF NOT EXISTS messages (
+                id          TEXT PRIMARY KEY,
+                session_id  TEXT NOT NULL,
+                seq         INTEGER NOT NULL,
+                role        TEXT NOT NULL,
+                content     TEXT NOT NULL,
+                media_refs  TEXT,
+                tool_call_id TEXT,
+                tool_name   TEXT,
+                tool_calls  TEXT,
+                created_at  INTEGER NOT NULL,
+                FOREIGN KEY (session_id) REFERENCES sessions(id) ON DELETE CASCADE
+            )
+            "#,
+        )
+        .execute(&self.pool)
+        .await?;
+
+        sqlx::query(
+            r#"
+            CREATE INDEX IF NOT EXISTS idx_messages_session_seq
+            ON messages(session_id, seq)
+            "#,
+        )
+        .execute(&self.pool)
+        .await?;
+
+        Ok(())
+    }
+
+    /// 获取连接池引用（供内部 CRUD 使用）
+    pub(crate) fn pool(&self) -> &Pool<Sqlite> {
+        &self.pool
+    }
+}