//! `SQLite` schema definition for the message log database.

use rusqlite::Connection;
use anyhow::Result;

/// Create the message log's tables and indexes if they don't already
/// exist (`messages`, `archives`, `blobs`).
///
/// Why: idempotent via `CREATE TABLE/INDEX IF NOT EXISTS`, so it's safe
/// to call on every `open_or_create`.
///
/// Return: `Ok(())` on success, or the underlying `SQLite` error.
pub fn init_schema(conn: &Connection) -> Result<()> {
    conn.execute_batch("PRAGMA foreign_keys = ON;")?;
    conn.execute_batch(
        "
        CREATE TABLE IF NOT EXISTS messages (
            id INTEGER PRIMARY KEY AUTOINCREMENT,
            session_id TEXT NOT NULL,
            role TEXT NOT NULL,
            content TEXT,
            tool_call_id TEXT,
            tool_name TEXT,
            tool_arguments TEXT,
            created_at INTEGER NOT NULL,
            FOREIGN KEY (session_id) REFERENCES archives(session_id)
        );

        CREATE TABLE IF NOT EXISTS archives (
            id INTEGER PRIMARY KEY AUTOINCREMENT,
            session_id TEXT NOT NULL UNIQUE,
            title TEXT,
            model TEXT,
            created_at INTEGER NOT NULL,
            updated_at INTEGER NOT NULL,
            message_count INTEGER DEFAULT 0,
            token_count INTEGER DEFAULT 0,
            summary TEXT
        );

        CREATE INDEX IF NOT EXISTS idx_messages_session_id ON messages(session_id);
        CREATE INDEX IF NOT EXISTS idx_messages_created_at ON messages(created_at);
        CREATE INDEX IF NOT EXISTS idx_archives_created_at ON archives(created_at);

        CREATE TABLE IF NOT EXISTS blobs (
            id INTEGER PRIMARY KEY AUTOINCREMENT,
            session_id TEXT NOT NULL,
            blob_key TEXT NOT NULL,
            data BLOB NOT NULL,
            mime_type TEXT,
            created_at INTEGER NOT NULL,
            UNIQUE(session_id, blob_key)
        );
        "
    )?;
    Ok(())
}