/**
 * Swarm Assistent — disk persistence for chats + UI state (Assistent/chats/, Assistent/ui-state.json).
 * Loaded after assistent.api.js and before assistent.js.
 */
window.SA = window.SA || {};

(function () {
    const LS_CHATS = 'swarm_assistent_chats_v1';
    const LS_MIGRATED = 'swarm_assistent_chats_on_disk_v1';
    const SAVE_DEBOUNCE_MS = 700;

    const timers = { chats: new Map(), ui: null };

    function request(name, body) {
        if (typeof SA.request === 'function') {
            return SA.request(name, body);
        }
        return new Promise((resolve, reject) => {
            if (typeof genericRequest !== 'function') {
                reject(new Error('genericRequest unavailable'));
                return;
            }
            genericRequest(
                name,
                body || {},
                (data) => (data && data.error ? reject(new Error(String(data.error))) : resolve(data)),
                0,
                (err) => reject(err instanceof Error ? err : new Error(String(err || 'request failed'))),
            );
        });
    }

    function normalizeChat(raw) {
        if (!raw || !raw.id) {
            return null;
        }
        return {
            id: String(raw.id),
            title: String(raw.title || 'Новый чат'),
            createdAt: Number(raw.createdAt) || Date.now(),
            updatedAt: Number(raw.updatedAt) || Number(raw.createdAt) || Date.now(),
            messages: Array.isArray(raw.messages) ? raw.messages : [],
            params: raw.params && typeof raw.params === 'object' ? raw.params : null,
        };
    }

    function readLocalChats() {
        try {
            const parsed = JSON.parse(localStorage.getItem(LS_CHATS) || 'null');
            if (Array.isArray(parsed?.chats)) {
                return parsed.chats.map(normalizeChat).filter(Boolean);
            }
        } catch (e) { /* ignore */ }
        return [];
    }

    /** One-shot lift of the browser-only history onto the data volume. */
    async function migrateLocalChatsToDisk() {
        if (localStorage.getItem(LS_MIGRATED) === '1') {
            return [];
        }
        const local = readLocalChats().filter((c) => (c.messages || []).length > 0);
        localStorage.setItem(LS_MIGRATED, '1');
        if (!local.length) {
            return [];
        }
        for (const chat of local) {
            try {
                await saveChat(chat, { immediate: true });
            } catch (e) {
                console.warn('Assistent: chat migration failed', chat.id, e);
            }
        }
        return local;
    }

    /** Disk chats, newest first. Falls back to a localStorage migration when the volume is empty. */
    async function loadChats() {
        let chats = [];
        try {
            const data = await request('AssistentListChats', { with_messages: true });
            chats = (data?.chats || []).map(normalizeChat).filter(Boolean);
        } catch (e) {
            console.warn('Assistent: disk chats unavailable', e);
            return null;
        }
        if (!chats.length) {
            const migrated = await migrateLocalChatsToDisk();
            if (migrated.length) {
                chats = migrated;
            }
        } else {
            localStorage.setItem(LS_MIGRATED, '1');
        }
        return chats.sort((a, b) => (b.updatedAt || 0) - (a.updatedAt || 0));
    }

    async function getChat(id) {
        if (!id) {
            return null;
        }
        const data = await request('AssistentGetChat', { id });
        return normalizeChat(data?.chat);
    }

    function saveChat(chat, { immediate = false } = {}) {
        const clean = normalizeChat(chat);
        if (!clean) {
            return Promise.resolve(null);
        }
        const send = () => {
            timers.chats.delete(clean.id);
            return request('AssistentSaveChat', {
                id: clean.id,
                title: clean.title,
                messages: clean.messages,
                params: clean.params,
                createdAt: clean.createdAt,
                updatedAt: clean.updatedAt,
            });
        };
        if (immediate) {
            const pending = timers.chats.get(clean.id);
            if (pending) {
                clearTimeout(pending);
            }
            return send();
        }
        const pending = timers.chats.get(clean.id);
        if (pending) {
            clearTimeout(pending);
        }
        timers.chats.set(clean.id, setTimeout(() => {
            send().catch((e) => console.warn('Assistent: chat save failed', clean.id, e));
        }, SAVE_DEBOUNCE_MS));
        return Promise.resolve(null);
    }

    function deleteChat(id) {
        if (!id) {
            return Promise.resolve(null);
        }
        const pending = timers.chats.get(id);
        if (pending) {
            clearTimeout(pending);
            timers.chats.delete(id);
        }
        return request('AssistentDeleteChat', { id });
    }

    async function loadUiState() {
        try {
            const data = await request('AssistentGetUiState', {});
            const ui = data?.ui_state;
            return ui && typeof ui === 'object' ? ui : null;
        } catch (e) {
            return null;
        }
    }

    function saveUiState(uiState, { immediate = false } = {}) {
        if (!uiState || typeof uiState !== 'object') {
            return Promise.resolve(null);
        }
        const send = () => {
            timers.ui = null;
            return request('AssistentSaveUiState', { ui_state: uiState });
        };
        if (timers.ui) {
            clearTimeout(timers.ui);
            timers.ui = null;
        }
        if (immediate) {
            return send();
        }
        timers.ui = setTimeout(() => {
            send().catch((e) => console.warn('Assistent: ui-state save failed', e));
        }, SAVE_DEBOUNCE_MS);
        return Promise.resolve(null);
    }

    SA.persist = {
        LS_CHATS,
        loadChats,
        getChat,
        saveChat,
        deleteChat,
        loadUiState,
        saveUiState,
    };
})();