const Database = require('better-sqlite3');
const schema = require('./schema');
const {getEnv, SQLITE } = require('@nexusai/shared');

let db;  // Declare db variable in a scope accessible to all functions

function getDB() {
    if (!db) {
        const path = getEnv('SQLITE_PATH', SQLITE.DEFAULT_PATH);
        db = new Database(path);

        db.pragma('journal_mode = WAL');
        db.pragma('foreign_keys = ON');

        db.exec(schema);

        try{
            db.exec(`ALTER TABLE sessions ADD COLUMN name TEXT`)
        } catch {}

        try {
            db.exec(`ALTER TABLE sessions ADD COLUMN project_id INTEGER REFERENCES projects(id)`);
        } catch {}

        try {
            db.exec(`CREATE INDEX IF NOT EXISTS idx_sessions_project ON sessions(project_id)`);
        } catch {}  

        try {
            db.exec(`ALTER TABLE projects ADD COLUMN isolated INTEGER NOT NULL DEFAULT 0`);
        } catch {}
        
        try {
            db.exec(`ALTER TABLE projects ADD COLUMN notes TEXT`);  // ← add this
        } catch {}

        try { 
            db.exec(`ALTER TABLE projects ADD COLUMN system_prompt TEXT`); 
        } catch {}

        // Sync FTS index with any existing episodes data
        db.exec(`INSERT OR REPLACE INTO episodes_fts(rowid, user_message, ai_response) 
            SELECT id, user_message, ai_response FROM episodes`);

        console.log(`Connected to SQLite database at ${path}`);
    }
    return db;
}

module.exports = {
    getDB
};