import { writable, derived } from 'svelte/store';
import { liveQuery } from 'dexie';
import { db } from '$lib/db/schema';
import type { AgendaContext, Topic, HistoryEntry, ContextType } from '@ka-note/shared';

// --- Writable UI state ---
export const currentContextId = writable<string>('daily-log');
export const currentMode = writable<'prep' | 'meeting'>('prep');
export const currentView = writable<string>('agenda');

// --- Session-only state (resets on tab close) ---
const isBrowser = typeof sessionStorage !== 'undefined';

function createSessionSet(key: string) {
	const stored = isBrowser ? sessionStorage.getItem(key) : null;
	const initial = stored ? new Set<string>(JSON.parse(stored)) : new Set<string>();
	const { subscribe, set, update } = writable(initial);

	return {
		subscribe,
		add(id: string) {
			update(s => {
				s.add(id);
				if (isBrowser) sessionStorage.setItem(key, JSON.stringify([...s]));
				return new Set(s);
			});
		},
		remove(id: string) {
			update(s => {
				s.delete(id);
				if (isBrowser) sessionStorage.setItem(key, JSON.stringify([...s]));
				return new Set(s);
			});
		},
		clear() {
			set(new Set());
			if (isBrowser) sessionStorage.removeItem(key);
		}
	};
}

export const processedTopicIds = createSessionSet('ka-note-processed');

// --- UI-only state ---
export const collapsedTopicIds = writable(new Set<string>());

// --- Reactive Dexie queries ---

export function contextsByType(type: ContextType) {
	return liveQuery(() =>
		db.contexts
			.where('type').equals(type)
			.filter(c => !c.deletedAt)
			.sortBy('sortOrder')
	);
}

export function allActiveContexts() {
	return liveQuery(() =>
		db.contexts.filter(c => !c.deletedAt).sortBy('sortOrder')
	);
}

export function contextById(id: string) {
	return liveQuery(() => db.contexts.get(id));
}

export function topicsForContext(contextId: string) {
	return liveQuery(() =>
		db.topics
			.where('contextId').equals(contextId)
			.filter(t => !t.deletedAt)
			.sortBy('sortOrder')
	);
}

export function historyForTopic(topicId: string) {
	return liveQuery(() =>
		db.historyEntries
			.where('topicId').equals(topicId)
			.filter(h => !h.deletedAt)
			.sortBy('sortOrder')
	);
}

export function allHistoryForContext(contextId: string) {
	return liveQuery(async () => {
		const topics = await db.topics
			.where('contextId').equals(contextId)
			.filter(t => !t.deletedAt)
			.toArray();
		const topicIds = topics.map(t => t.id);
		const entries = await db.historyEntries
			.where('topicId').anyOf(topicIds)
			.filter(h => !h.deletedAt)
			.toArray();
		return entries.map(e => ({
			...e,
			topicTitle: topics.find(t => t.id === e.topicId)?.title ?? ''
		}));
	});
}

export function ratingsForHistoryEntry(historyEntryId: string) {
	return liveQuery(() =>
		db.ratings
			.where('historyEntryId').equals(historyEntryId)
			.filter(r => !r.deletedAt)
			.toArray()
	);
}

export function ratingsForPerson(personName: string) {
	return liveQuery(() =>
		db.ratings
			.where('personName').equals(personName)
			.filter(r => !r.deletedAt)
			.toArray()
	);
}