import { error, fail } from '@sveltejs/kit';
import type { Actions, PageServerLoad } from './$types';
import { requireUser } from '#lib/server/auth.js';
import { getTaxonomy, listPieces } from '#lib/server/content.js';
import {
	addPieceUsage,
	addShowSection,
	getShow,
	movePieceUsage,
	moveShowSection,
	removePieceUsage,
	removeShowSection,
	saveShowMetadata,
	updatePieceUsage,
	updateShowSection,
	type EditableShowStatus,
	type UsageStatus
} from '#lib/server/shows.js';

function text(data: FormData, name: string) {
	return String(data.get(name) || '');
}

function nullableDuration(data: FormData) {
	const value = text(data, 'explicitDurationSeconds').trim();
	return value === '' ? null : Number(value);
}

function pieceDurationInSeconds(data: FormData) {
	return Math.round(Number(data.get('durationMinutes')) * 60);
}

function berlinLocalToUtc(value: string): string | null {
	if (!value) return null;
	const match = /^(\d{4})-(\d{2})-(\d{2})T(\d{2}):(\d{2})$/.exec(value);
	if (!match) throw new Error('INVALID_TIMESTAMP');
	const parts = match.slice(1).map(Number);
	const localMilliseconds = Date.UTC(parts[0], parts[1] - 1, parts[2], parts[3], parts[4]);
	let candidate = localMilliseconds;
	for (let attempt = 0; attempt < 2; attempt += 1) {
		const formatted = new Intl.DateTimeFormat('en-CA', {
			timeZone: 'Europe/Berlin',
			year: 'numeric',
			month: '2-digit',
			day: '2-digit',
			hour: '2-digit',
			minute: '2-digit',
			hourCycle: 'h23'
		}).formatToParts(new Date(candidate));
		const read = (type: Intl.DateTimeFormatPartTypes) =>
			Number(formatted.find((part) => part.type === type)?.value);
		candidate +=
			localMilliseconds -
			Date.UTC(read('year'), read('month') - 1, read('day'), read('hour'), read('minute'));
	}
	return new Date(candidate).toISOString();
}

function berlinInput(value: string | null) {
	if (!value) return '';
	const parts = new Intl.DateTimeFormat('en-CA', {
		timeZone: 'Europe/Berlin',
		year: 'numeric',
		month: '2-digit',
		day: '2-digit',
		hour: '2-digit',
		minute: '2-digit',
		hourCycle: 'h23'
	}).formatToParts(new Date(value));
	const read = (type: Intl.DateTimeFormatPartTypes) =>
		parts.find((part) => part.type === type)?.value ?? '';
	return `${read('year')}-${read('month')}-${read('day')}T${read('hour')}:${read('minute')}`;
}

function actionError(cause: unknown) {
	const code = cause instanceof Error ? cause.message : '';
	if (code === 'CONFLICT')
		return {
			status: 409,
			error: 'Die Sendung wurde inzwischen geändert. Bitte neu laden.',
			conflict: true
		};
	if (code === 'SHOW_COMPLETED')
		return { status: 409, error: 'Abgeschlossene Sendungen können nicht bearbeitet werden.' };
	if (code === 'PIECE_NOT_READY')
		return { status: 400, error: 'Nur sendefertige Pieces können eingeplant werden.' };
	if (code === 'NOT_FOUND') return { status: 404, error: 'Der Eintrag wurde nicht gefunden.' };
	if (code === 'INVALID_DURATION')
		return { status: 400, error: 'Piece-Dauern müssen zwischen 0 und 1.440 Minuten liegen.' };
	if (code.startsWith('INVALID_'))
		return { status: 400, error: 'Mindestens ein Feld ist ungültig oder zu lang.' };
	return { status: 500, error: 'Die Änderung konnte nicht gespeichert werden.' };
}

function attempt(intent: string, operation: () => unknown) {
	try {
		return { intent, success: 'Änderung gespeichert.', result: operation() };
	} catch (cause) {
		return fail(actionError(cause).status, { intent, ...actionError(cause) });
	}
}

export const load: PageServerLoad = ({ locals, params, url }) => {
	requireUser(locals.user);
	const show = getShow(params.id);
	if (!show) error(404, 'Sendung nicht gefunden');
	return {
		show,
		startsAtLocal: berlinInput(show.startsAtUtc),
		pieces: listPieces({
			statuses: ['ready'],
			query: url.searchParams.get('q') ?? '',
			categoryId: url.searchParams.get('category') ?? ''
		}),
		taxonomy: getTaxonomy(),
		filters: {
			query: url.searchParams.get('q') ?? '',
			categoryId: url.searchParams.get('category') ?? ''
		}
	};
};

export const actions = {
	saveMetadata: async ({ locals, params, request }) => {
		requireUser(locals.user);
		const data = await request.formData();
		return attempt('saveMetadata', () =>
			saveShowMetadata(params.id, Number(data.get('revision')), {
				title: text(data, 'title'),
				startsAtUtc: berlinLocalToUtc(text(data, 'startsAt')),
				twitchTitle: text(data, 'twitchTitle'),
				announcementText: text(data, 'announcementText'),
				status: text(data, 'status') as EditableShowStatus
			})
		);
	},
	addSection: async ({ locals, params, request }) => {
		requireUser(locals.user);
		const data = await request.formData();
		return attempt('addSection', () =>
			addShowSection(params.id, Number(data.get('revision')), {
				name: text(data, 'name'),
				categoryId: text(data, 'categoryId') || null,
				explicitDurationSeconds: nullableDuration(data)
			})
		);
	},
	updateSection: async ({ locals, params, request }) => {
		requireUser(locals.user);
		const data = await request.formData();
		return attempt('updateSection', () =>
			updateShowSection(params.id, text(data, 'sectionId'), Number(data.get('revision')), {
				name: text(data, 'name'),
				categoryId: text(data, 'categoryId') || null,
				explicitDurationSeconds: nullableDuration(data)
			})
		);
	},
	removeSection: async ({ locals, params, request }) => {
		requireUser(locals.user);
		const data = await request.formData();
		return attempt('removeSection', () =>
			removeShowSection(params.id, text(data, 'sectionId'), Number(data.get('revision')))
		);
	},
	moveSection: async ({ locals, params, request }) => {
		requireUser(locals.user);
		const data = await request.formData();
		return attempt('moveSection', () =>
			moveShowSection(
				params.id,
				text(data, 'sectionId'),
				Number(data.get('position')),
				Number(data.get('revision'))
			)
		);
	},
	addUsage: async ({ locals, params, request }) => {
		requireUser(locals.user);
		const data = await request.formData();
		return attempt('addUsage', () =>
			addPieceUsage(params.id, Number(data.get('revision')), {
				pieceId: text(data, 'pieceId'),
				sectionId: text(data, 'sectionId') || null
			})
		);
	},
	updateUsage: async ({ locals, params, request }) => {
		requireUser(locals.user);
		const data = await request.formData();
		return attempt('updateUsage', () =>
			updatePieceUsage(params.id, text(data, 'usageId'), Number(data.get('revision')), {
				title: text(data, 'title'),
				durationSeconds: pieceDurationInSeconds(data),
				ownNotes: text(data, 'ownNotes'),
				intro: text(data, 'intro'),
				research: text(data, 'research'),
				moderation: text(data, 'moderation'),
				transition: text(data, 'transition'),
				presentation: text(data, 'presentation'),
				status: text(data, 'status') as UsageStatus
			})
		);
	},
	removeUsage: async ({ locals, params, request }) => {
		requireUser(locals.user);
		const data = await request.formData();
		return attempt('removeUsage', () =>
			removePieceUsage(params.id, text(data, 'usageId'), Number(data.get('revision')))
		);
	},
	moveUsage: async ({ locals, params, request }) => {
		requireUser(locals.user);
		const data = await request.formData();
		return attempt('moveUsage', () =>
			movePieceUsage(params.id, text(data, 'usageId'), Number(data.get('revision')), {
				sectionId: text(data, 'sectionId') || null,
				position: Number(data.get('position'))
			})
		);
	}
} satisfies Actions;