import { query } from './_generated/server.js';
import { requireOwner } from './lib.js';
import { dashboardRangeValidator } from './validators.js';

const rangeDays = {
	'7d': 7,
	'30d': 30,
	'90d': 90,
	'1y': 365
} as const;

function dayKey(date: Date) {
	return date.toISOString().slice(0, 10);
}

function daysAgo(days: number) {
	const date = new Date();
	date.setHours(0, 0, 0, 0);
	date.setDate(date.getDate() - days);
	return dayKey(date);
}

export const summary = query({
	args: { range: dashboardRangeValidator },
	handler: async (ctx, args) => {
		const owner = await requireOwner(ctx);
		const selectedDays = rangeDays[args.range];
		const entries = await ctx.db
			.query('entries')
			.withIndex('by_owner_and_entryDate', (q) => q.eq('owner', owner))
			.order('desc')
			.take(Math.min(800, selectedDays * 3));
		const activeEntries = entries.filter((entry) => !entry.archived);
		const rangeStart = daysAgo(selectedDays - 1);
		const last7Start = daysAgo(6);
		const last30Start = daysAgo(29);
		const rangedEntries = activeEntries.filter((entry) => entry.entryDate >= rangeStart);
		const last7 = activeEntries.filter((entry) => entry.entryDate >= last7Start);
		const last30 = activeEntries.filter((entry) => entry.entryDate >= last30Start);
		const moodCounts: Record<string, number> = {};
		const dailyCounts = new Map<string, number>();
		const tagCounts: Record<string, number> = {};

		for (const entry of rangedEntries) {
			moodCounts[entry.mood] = (moodCounts[entry.mood] ?? 0) + 1;
			dailyCounts.set(entry.entryDate, (dailyCounts.get(entry.entryDate) ?? 0) + 1);

			for (const tagName of entry.tagNames) {
				tagCounts[tagName] = (tagCounts[tagName] ?? 0) + 1;
			}
		}

		let currentStreak = 0;
		for (let offset = 0; offset < 365; offset += 1) {
			const key = daysAgo(offset);
			if (!activeEntries.some((entry) => entry.entryDate === key)) break;
			currentStreak += 1;
		}

		const dailySeries = Array.from({ length: selectedDays }, (_, index) => {
			const date = daysAgo(selectedDays - 1 - index);
			return { date, count: dailyCounts.get(date) ?? 0 };
		});

		return {
			totalEntries: activeEntries.length,
			entriesThisWeek: last7.length,
			entriesThisMonth: last30.length,
			entriesInRange: rangedEntries.length,
			range: args.range,
			currentStreak,
			averageWords:
				activeEntries.length === 0
					? 0
					: Math.round(
							activeEntries.reduce(
								(sum, entry) => sum + entry.plainText.split(/\s+/).filter(Boolean).length,
								0
							) / activeEntries.length
						),
			moodCounts,
			dailySeries,
			topTags: Object.entries(tagCounts)
				.sort((a, b) => b[1] - a[1])
				.slice(0, 8)
				.map(([name, count]) => ({ name, count })),
			insight:
				last7.length >= 5
					? 'You have a strong writing rhythm this week.'
					: last7.length >= 2
						? 'A few reflections this week are already building momentum.'
						: 'A short entry today is enough to restart the thread.'
		};
	}
});