// LLM gateway config — localStorage for the secret, env only for non-secrets.
//
// The app is a static Vite site with no server. The API key is a secret and
// must never be baked into the build — it lives only in the browser's
// localStorage (→ ⚙️ dialog). Gateway URL and model are non-secret and may
// come from VITE env as defaults with a localStorage override; the key never
// does.

const STORAGE_KEY = 'flow-state:llm';

const DEFAULTS = {
    gatewayUrl: 'https://ai-gateway.vercel.sh/v1',
    model: 'meta/muse-spark-1.3-contributor',
    apiKey: '',
};

function readEnv() {
    try {
        const env = import.meta.env || {};
        return {
            gatewayUrl: env.VITE_AI_GATEWAY_URL || null,
            model: env.VITE_AI_MODEL || null,
            // apiKey intentionally NOT read from env — see module comment.
        };
    } catch {
        return { gatewayUrl: null, model: null };
    }
}

function readStorage() {
    try {
        const raw = localStorage.getItem(STORAGE_KEY);
        if (!raw) return {};
        const parsed = JSON.parse(raw);
        return parsed && typeof parsed === 'object' ? parsed : {};
    } catch {
        return {};
    }
}

/** Resolved config — key from localStorage only (never env); URL/model from localStorage > env > defaults. */
export function getLlmConfig() {
    const env = readEnv();
    const stored = readStorage();
    const gatewayUrl = stored.gatewayUrl || env.gatewayUrl || DEFAULTS.gatewayUrl;
    const model = stored.model || env.model || DEFAULTS.model;
    const key = typeof stored.apiKey === 'string' ? stored.apiKey.trim() : '';
    return {
        gatewayUrl: String(gatewayUrl || DEFAULTS.gatewayUrl).trim() || DEFAULTS.gatewayUrl,
        model: String(model || DEFAULTS.model).trim() || DEFAULTS.model,
        apiKey: key,
        isConfigured: key.length > 0,
        defaults: { ...DEFAULTS },
        env: { ...env },
        stored: { ...stored },
    };
}

/** Merge patch into localStorage. Pass null/'' to clear a field. */
export function setLlmConfig(patch) {
    const current = readStorage();
    const next = { ...current };
    for (const k of ['gatewayUrl', 'model', 'apiKey']) {
        if (patch && Object.prototype.hasOwnProperty.call(patch, k)) {
            const v = patch[k];
            if (v == null || v === '') {
                delete next[k];
            } else {
                next[k] = String(v).trim();
            }
        }
    }
    try {
        if (!Object.keys(next).length) localStorage.removeItem(STORAGE_KEY);
        else localStorage.setItem(STORAGE_KEY, JSON.stringify(next));
    } catch {
        // storage full / blocked — ignore, caller sees isConfigured false
    }
    return getLlmConfig();
}

export function clearLlmConfig() {
    try { localStorage.removeItem(STORAGE_KEY); } catch { /* ignore */ }
    return getLlmConfig();
}

export const LLM_STORAGE_KEY = STORAGE_KEY;
export const LLM_DEFAULTS = DEFAULTS;