import { type NextMiddleware, NextResponse } from "next/server"

import type { MiddlewareMatcher } from "@/types/middleware"

/*
    Middleware function to normalize date formats to support
    YYYY-MM-D and YYYY-MM-DD since the current web uses YYYY-MM-D
    in the URL as parameters (toDate and fromDate)
*/
const legacyDatePattern = /^([12]\d{3}-(0[1-9]|1[0-2])-([1-9]))$/

function normalizeDate(date: string): string {
  const datePattern = /^\d{4}-\d{1,2}-\d{1,2}$/
  if (datePattern.test(date)) {
    const [year, month, day] = date.split("-").map(Number)
    return `${year}-${String(month).padStart(2, "0")}-${String(day).padStart(2, "0")}`
  }
  return date
}

export const middleware: NextMiddleware = (request) => {
  const url = request.nextUrl.clone()
  const { searchParams } = url

  if (
    legacyDatePattern.test(searchParams.get("fromdate")!) ||
    legacyDatePattern.test(searchParams.get("todate")!)
  ) {
    const fromDate = searchParams.get("fromdate")!
    url.searchParams.set("fromdate", normalizeDate(fromDate))

    const toDate = searchParams.get("todate")!
    url.searchParams.set("todate", normalizeDate(toDate))
    return NextResponse.redirect(url)
  } else {
    const headers = new Headers(request.headers)
    headers.set("x-continue", "1")
    return NextResponse.next({
      headers,
    })
  }
}

export const matcher: MiddlewareMatcher = (request) => {
  const { searchParams } = request.nextUrl
  return searchParams.has("fromdate") || searchParams.has("todate")
}