/**
 * Guide Page Controller
 */

class GuidePage {
    constructor(app) {
        this.app = app;
    }

    async init() {
        // EPG guide will lazy load when shown
    }

    async loadCatalog() {
        const channelList = this.app.channelList;
        const revision = API.liveCatalogRevision || 0;
        if (channelList.guideCatalog && channelList.guideCatalogRevision === revision) return;
        if (this.catalogLoad?.revision === revision) return this.catalogLoad.promise;
        const promise = (async () => {
            const channels = [];
            let cursor;
            do {
                // Guide ignores group visibility; EpgGuide filters individually hidden channels.
                const result = await API.channels.liveCatalog({ limit: 500, cursor, includeHidden: true });
                if (revision !== (API.liveCatalogRevision || 0)) throw new Error('Catalogue changed');
                channels.push(...result.items);
                const next = result.page.hasMore ? result.page.nextCursor : null;
                if (result.page.hasMore && (!next || next === cursor)) throw new Error('Invalid catalogue cursor');
                cursor = next;
            } while (cursor);
            await channelList.loadHiddenItems();
            if (revision !== (API.liveCatalogRevision || 0)) throw new Error('Catalogue changed');
            channelList.guideCatalog = channels;
            channelList.guideCatalogRevision = revision;
        })();
        this.catalogLoad = { revision, promise };
        try { await promise; }
        finally {
            if (this.catalogLoad?.promise === promise) this.catalogLoad = null;
        }
    }

    async show() {
        const visit = this.visit = (this.visit || 0) + 1;
        const container = this.app.epgGuide.container;
        const channelList = this.app.channelList;
        const needsCatalog = !channelList.guideCatalog || channelList.guideCatalogRevision !== (API.liveCatalogRevision || 0);
        if (needsCatalog) {
            container.textContent = 'Loading…';
            container.setAttribute('aria-busy', 'true');
        }
        try {
            await this.loadCatalog();
            if (visit !== this.visit) return;
            if (!this.app.epgGuide.programmes?.length) {
                await this.app.epgGuide.loadEpg();
            } else {
                this.app.epgGuide.render();
            }
        } catch (err) {
            if (visit !== this.visit) return;
            container.textContent = 'Error loading channels';
            const retry = document.createElement('button');
            retry.type = 'button';
            retry.className = 'btn btn-sm';
            retry.textContent = 'Retry';
            retry.addEventListener('click', () => this.show());
            container.appendChild(retry);
        } finally {
            if (visit === this.visit) container.setAttribute('aria-busy', 'false');
        }
    }

    hide() {
        this.visit = (this.visit || 0) + 1;
        this.app.epgGuide.container.setAttribute('aria-busy', 'false');
    }

}

window.GuidePage = GuidePage;