// This Saltcorn instance's site-sync identity (env_id, label, policies).
//
// Stored in _sc_config (key "site_sync_env") rather than a table. _sc_config
// survives backup AND is restored BEFORE the plugin's onLoad runs, so a restored
// instance keeps its env_id and onLoad does not create a duplicate (see
// lib/common/configStore.js). Reads are DB-fresh (no in-process cache needed).

const { randomUuid }        = require("./ids");
const { readKey, writeKey } = require("./common/configStore");
const {
    SYNC_MODES,
    DELETE_POLICY,
    APPLY_POLICY
} = require("./constants");


const ENV_KEY = "site_sync_env";


const getEnv = async () => {
    return (await readKey(ENV_KEY)) || null;
};


const initEnvIfMissing = async () => {
    const existing = await getEnv();
    if (existing) {
        return existing;
    }
    const env = {
        env_id:          randomUuid(),
        env_label:       null,
        // Full-mirror is the default posture: the target converges exactly to the
        // source, pruning entities the source no longer has (metadata prunes freely;
        // data-bearing drops are still gated by on_delete + an explicit allow-list).
        sync_mode:       SYNC_MODES.MIRROR,
        on_delete:       DELETE_POLICY.CONFIRM,
        on_apply:        APPLY_POLICY.CONFIRM,
        require_tls:     0,
        created_at:      new Date().toISOString()
    };
    await writeKey(ENV_KEY, env);
    return env;
};


const setEnvFields = async (patch) => {
    const env = await getEnv();
    if (!env) {
        return null;
    }
    const next = Object.assign({}, env, patch);
    await writeKey(ENV_KEY, next);
    return next;
};


// The identity is created in onLoad, so a missing one on a live request is an
// installation fault; fail loudly instead of answering with a null env_id.
const requireEnv = async () => {
    const env = await getEnv();
    if (!env) {
        throw new Error("site-sync identity (site_sync_env) is missing; reload the plugin");
    }
    return env;
};


module.exports = {
    getEnv,
    requireEnv,
    initEnvIfMissing,
    setEnvFields
};