import { env } from '../env';
import { loadYaml, validateUuid } from './parser';
import { resolveTheme, VALID_LAYOUTS } from './theme';
import { slugify, AppConfig, SubpageConfig, GalleryYaml, SettingsYaml, GridConfig } from './schema';

export * from './schema';
export * from './theme';

let _config: AppConfig | null = null;
export function getConfig(): AppConfig {
    const isDev = process.env.NODE_ENV !== 'production';
    if (_config && !isDev) return _config;

    const apiUrl = env.IMMICH_API_URL;
    const apiKey = env.IMMICH_API_KEY;
    const authSecret = env.AUTH_SECRET || apiKey;

    if (!env.AUTH_SECRET && process.env.NODE_ENV === 'production') {
        console.warn('\n⚠️  SECURITY WARNING: AUTH_SECRET is not set. Falling back to IMMICH_API_KEY.\n   Please set a long random string as AUTH_SECRET in your .env for better security.\n');
    }

    const gallery = loadYaml<GalleryYaml>('gallery.yaml');
    const settings = loadYaml<SettingsYaml>('settings.yaml') || {};

    if (!gallery || !apiKey || !apiUrl) {
        // Return dummy config if gallery.yaml is missing
        _config = {
            immich: { apiUrl: `${apiUrl}/api`, apiKey },
            authSecret,
            albums: [],
            standaloneAlbums: [],
            subpages: [],
            siteTitle: env.SITE_TITLE || 'Immich Folio',
            siteSubtitle: env.SITE_SUBTITLE || 'Setup Required',
            seo: { title: 'Setup Required', description: 'Please configure Immich Folio', noIndex: true, noFollow: true },
            heroImages: [],
            exifOnHover: true,
            grid: { columns: 3, gap: 12, aspectRatio: '1', layout: 'masonry' },
            theme: resolveTheme('studio'),
            footer: null,
            legal: { enabled: false, name: '', address: '', zipCity: '', country: '' },
            map: false,
            transitions: false,
            albumOverrides: {},
            cacheTtl: env.CACHE_TTL * 1000,
            rateLimitRpm: env.RATE_LIMIT_RPM,
            needsSetup: true
        };
        return _config;
    }

    const theme = resolveTheme(settings.theme);

    const albumOverrides: Record<string, string> = {};

    function processAlbumEntry(entry: string | Record<string, string>, context: string): string {
        if (typeof entry === 'string') {
            return validateUuid(entry, context);
        }
        const [uuid, name] = Object.entries(entry)[0];
        const validatedUuid = validateUuid(uuid, context);
        albumOverrides[validatedUuid] = name;
        return validatedUuid;
    }

    const standaloneAlbumIds = (gallery.albums ?? []).map((entry) => processAlbumEntry(entry, 'gallery.yaml albums'));
    if (standaloneAlbumIds.length === 0 && (!gallery.subpages || (Array.isArray(gallery.subpages) ? gallery.subpages.length === 0 : Object.keys(gallery.subpages).length === 0))) {
        throw new Error('gallery.yaml must define at least one album or subpage');
    }

    let subpages: SubpageConfig[] = [];

    if (Array.isArray(gallery.subpages)) {
        subpages = gallery.subpages.map((sp) => {
            if (!sp.name || !sp.albums || sp.albums.length === 0) {
                throw new Error(`Subpage "${sp.name || '(unnamed)'}" must have a name and at least one album`);
            }
            return {
                name: sp.name,
                slug: slugify(sp.name),
                title: sp.title,
                subtitle: sp.subtitle,
                albumIds: sp.albums.map((entry) => processAlbumEntry(entry, `subpage "${sp.name}"`)),
                password: sp.password,
                ...(sp.grid ? {
                    grid: {
                        ...(sp.grid.columns != null ? { columns: sp.grid.columns } : {}),
                        ...(sp.grid.gap != null ? { gap: sp.grid.gap } : {}),
                        ...(sp.grid.aspectRatio != null ? { aspectRatio: sp.grid.aspectRatio } : {}),
                        ...(sp.grid.layout != null ? { layout: (VALID_LAYOUTS.includes(sp.grid.layout) ? sp.grid.layout : 'masonry') as GridConfig['layout'] } : {}),
                    },
                } : {}),
            };
        });
    } else if (gallery.subpages) {
        subpages = Object.entries(gallery.subpages).map(([name, value]) => {
            if (Array.isArray(value)) {
                return { name, slug: slugify(name), albumIds: value.map((entry) => processAlbumEntry(entry, `subpage "${name}"`)) };
            }
            interface SubpageObjectValue { title?: string; subtitle?: string; albums?: Array<string | Record<string, string>>; password?: string; grid?: { columns?: number; gap?: number; aspectRatio?: string; layout?: string; }; }
            const sp = value as SubpageObjectValue;
            const albumEntries = sp.albums || [];
            return {
                name,
                slug: slugify(name),
                title: sp.title,
                subtitle: sp.subtitle,
                albumIds: albumEntries.map((entry) => processAlbumEntry(entry, `subpage "${name}"`)),
                password: sp.password,
                ...(sp.grid ? {
                    grid: {
                        ...(sp.grid.columns != null ? { columns: sp.grid.columns } : {}),
                        ...(sp.grid.gap != null ? { gap: sp.grid.gap } : {}),
                        ...(sp.grid.aspectRatio != null ? { aspectRatio: sp.grid.aspectRatio } : {}),
                        ...(sp.grid.layout != null ? { layout: (VALID_LAYOUTS.includes(sp.grid.layout) ? sp.grid.layout : 'masonry') as GridConfig['layout'] } : {}),
                    },
                } : {}),
            };
        });
    }

    const subpageAlbumIds = new Set(subpages.flatMap((sp) => sp.albumIds));
    const allAlbumIds = [...new Set([...standaloneAlbumIds, ...subpageAlbumIds])];

    _config = {
        immich: { apiUrl: `${apiUrl}/api`, apiKey },
        authSecret,
        albums: allAlbumIds,
        standaloneAlbums: standaloneAlbumIds.filter((id) => !subpageAlbumIds.has(id)),
        subpages,
        siteTitle: settings.title ?? env.SITE_TITLE,
        siteSubtitle: settings.subtitle ?? env.SITE_SUBTITLE,
        seo: {
            title: settings.seo?.title || settings.title || env.SITE_TITLE || 'Gallery',
            description: settings.seo?.description || settings.subtitle || env.SITE_SUBTITLE || 'A curated photography portfolio',
            noIndex: settings.seo?.noIndex === true,
            noFollow: settings.seo?.noFollow === true,
        },
        heroImages: gallery.hero ? (Array.isArray(gallery.hero) ? gallery.hero : [gallery.hero]).map((id) => validateUuid(id, 'gallery.yaml hero')) : [],
        exifOnHover: settings.exifOnHover !== false,
        grid: {
            columns: settings.grid?.columns ?? 3,
            gap: settings.grid?.gap ?? 12,
            aspectRatio: settings.grid?.aspectRatio ?? '1',
            layout: (VALID_LAYOUTS.includes(settings.grid?.layout ?? '') ? settings.grid!.layout : 'masonry') as GridConfig['layout'],
        },
        theme,
        footer: settings.footer ? { name: settings.footer.name, instagram: settings.footer.instagram, email: settings.footer.email, website: settings.footer.website } : null,
        legal: {
            enabled: settings.legal?.enabled === true,
            name: settings.legal?.name || '',
            address: settings.legal?.address || '',
            zipCity: settings.legal?.zipCity || '',
            country: settings.legal?.country || '',
            email: settings.legal?.email,
            phone: settings.legal?.phone,
            taxId: settings.legal?.taxId,
            vatId: settings.legal?.vatId,
            extraInfo: settings.legal?.extraInfo,
        },
        map: settings.map === true,
        transitions: settings.transitions !== false,
        albumOverrides,
        cacheTtl: env.CACHE_TTL * 1000,
        rateLimitRpm: env.RATE_LIMIT_RPM,
        needsSetup: false
    };
    return _config;
}