import type { H3Event } from 'h3'

import {
	ADMIN_RANGES,
	type AdminRange,
	type ErrorSort,
	type SortDirection,
} from '../../shared/types/telemetry'
import { AdminApiError } from './errors'

const ERROR_SORTS = ['lastSeen', 'firstSeen', 'occurrences', 'installations'] as const
const SORT_DIRECTIONS = ['asc', 'desc'] as const

export interface ErrorQuery {
	range: AdminRange
	page: number
	pageSize: number
	search: string
	version: string | null
	platform: string | null
	errorType: string | null
	hasSample: boolean | null
	sort: ErrorSort
	direction: SortDirection
}

function single(value: unknown): string | undefined {
	return Array.isArray(value) ? String(value[0]) : value == null ? undefined : String(value)
}

function integer(value: unknown, fallback: number, minimum: number, maximum: number): number {
	const raw = single(value)
	if (raw === undefined || raw === '') return fallback
	if (!/^\d+$/.test(raw)) throw new AdminApiError(400, 'invalid_query', 'Invalid query parameters')
	const parsed = Number(raw)
	if (!Number.isSafeInteger(parsed) || parsed < minimum || parsed > maximum) {
		throw new AdminApiError(400, 'invalid_query', 'Invalid query parameters')
	}
	return parsed
}

function limited(value: unknown, maximum: number): string | null {
	const parsed = single(value)?.trim() ?? ''
	if (!parsed) return null
	if (parsed.length > maximum) {
		throw new AdminApiError(400, 'invalid_query', 'Invalid query parameters')
	}
	return parsed
}

export function parseRange(value: unknown): AdminRange {
	const parsed = single(value) ?? '30d'
	if (!ADMIN_RANGES.includes(parsed as AdminRange)) {
		throw new AdminApiError(400, 'invalid_range', 'Range must be 7d, 30d, 90d, or 365d')
	}
	return parsed as AdminRange
}

export function parseErrorQuery(query: Record<string, unknown>): ErrorQuery {
	const sort = single(query.sort) ?? 'lastSeen'
	const direction = single(query.direction) ?? 'desc'
	if (
		!ERROR_SORTS.includes(sort as ErrorSort) ||
		!SORT_DIRECTIONS.includes(direction as SortDirection)
	) {
		throw new AdminApiError(400, 'invalid_query', 'Invalid query parameters')
	}
	const sample = single(query.hasSample)
	if (sample !== undefined && sample !== 'true' && sample !== 'false') {
		throw new AdminApiError(400, 'invalid_query', 'Invalid query parameters')
	}
	return {
		range: parseRange(query.range),
		page: integer(query.page, 1, 1, 100_000),
		pageSize: integer(query.pageSize, 25, 1, 100),
		search: limited(query.search, 120) ?? '',
		version: limited(query.version, 64),
		platform: limited(query.platform, 32),
		errorType: limited(query.errorType, 128),
		hasSample: sample === undefined ? null : sample === 'true',
		sort: sort as ErrorSort,
		direction: direction as SortDirection,
	}
}

export function getQueryRecord(event: H3Event): Record<string, unknown> {
	const url = new URL(event.node.req.url ?? '/', 'http://localhost')
	return Object.fromEntries(url.searchParams.entries())
}

export function rangeDays(range: AdminRange): number {
	return Number.parseInt(range, 10)
}

export function startDay(range: AdminRange, now = new Date()): string {
	const date = new Date(Date.UTC(now.getUTCFullYear(), now.getUTCMonth(), now.getUTCDate()))
	date.setUTCDate(date.getUTCDate() - rangeDays(range) + 1)
	return date.toISOString().slice(0, 10)
}