"use client"

// Kontoinnstillinger (ADR-021): sett/fjern passord (valgfritt tillegg til
// magic-link), aktiver/deaktiver 2FA. Frivillig 2FA-oppsett herfra bruker
// SAMME TwoFactorSetupForm som den tvungne flyten rett etter innlogging
// (forced=false her -- kun tekst-copyen skiller de to).

import type React from "react"
import { useEffect, useState } from "react"
import Link from "next/link"
import { ArrowLeft, KeyRound, Lock, ShieldCheck, ShieldOff } from "lucide-react"
import { Button } from "@/components/ui/button"
import { Input } from "@/components/ui/input"
import { Label } from "@/components/ui/label"
import { TwoFactorSetupForm } from "@/components/two-factor-flow"

type Me = {
  id: string
  email: string
  display_name: string
  has_password: boolean
  two_factor_method: "totp" | "email" | null
}

export function AccountSettings() {
  const [me, setMe] = useState<Me | null>(null)
  const [loading, setLoading] = useState(true)
  const [settingUp2fa, setSettingUp2fa] = useState(false)

  async function loadMe() {
    try {
      const res = await fetch("/auth/me", { credentials: "include" })
      if (res.ok) setMe(await res.json())
    } finally {
      setLoading(false)
    }
  }

  useEffect(() => {
    void loadMe()
  }, [])

  async function handleDisable2fa() {
    if (!confirm("Er du sikker på at du vil slå av topartsautentisering?")) return
    const res = await fetch("/auth/2fa/disable", { method: "POST", credentials: "include" })
    if (res.ok) void loadMe()
  }

  if (loading) {
    return (
      <div className="flex min-h-[100dvh] flex-col items-center justify-center bg-background">
        <div
          aria-hidden="true"
          className="size-10 animate-spin rounded-full border-4 border-primary/20 border-t-primary"
        />
      </div>
    )
  }

  if (!me) return null

  return (
    <div className="flex min-h-[100dvh] flex-col bg-background">
      <header className="sticky top-0 z-10 border-b border-border bg-background/80 backdrop-blur">
        <div className="mx-auto flex w-full max-w-2xl items-center gap-3 px-5 py-4">
          <Link
            href="/dashboard"
            aria-label="Tilbake til dashbord"
            className="flex size-10 shrink-0 items-center justify-center rounded-xl border border-border bg-card text-muted-foreground transition-colors hover:bg-accent/50 hover:text-foreground"
          >
            <ArrowLeft aria-hidden="true" className="size-5" />
          </Link>
          <div className="flex min-w-0 flex-col">
            <span className="text-xs font-semibold uppercase tracking-wide text-muted-foreground">Konto</span>
            <h1 className="truncate text-xl font-extrabold tracking-tight text-foreground">{me.email}</h1>
          </div>
        </div>
      </header>

      <main className="mx-auto w-full max-w-2xl flex-1 px-5 py-6 sm:py-8">
        {settingUp2fa ? (
          <div className="rounded-3xl border border-border bg-card p-6 shadow-sm shadow-black/5 sm:p-8">
            <TwoFactorSetupForm
              forced={false}
              onSuccess={() => {
                setSettingUp2fa(false)
                void loadMe()
              }}
            />
          </div>
        ) : (
          <div className="flex flex-col gap-6">
            <PasswordSection hasPassword={me.has_password} onChanged={loadMe} />

            <section className="flex flex-col gap-3 rounded-3xl border border-border bg-card p-5 shadow-sm shadow-black/5 sm:p-6">
              <div className="flex items-center gap-2.5">
                <div className="flex size-10 items-center justify-center rounded-xl bg-primary/15">
                  <ShieldCheck aria-hidden="true" className="size-5 text-primary" />
                </div>
                <h2 className="text-base font-bold text-foreground">Topartsautentisering (2FA)</h2>
              </div>

              {me.two_factor_method ? (
                <>
                  <p className="text-sm leading-relaxed text-muted-foreground text-pretty">
                    Aktivert med{" "}
                    <span className="font-semibold text-foreground">
                      {me.two_factor_method === "totp" ? "autentisator-app" : "engangskode på e-post"}
                    </span>
                    .
                  </p>
                  <Button
                    type="button"
                    variant="outline"
                    onClick={handleDisable2fa}
                    className="h-12 w-fit rounded-2xl font-semibold text-destructive hover:text-destructive"
                  >
                    <ShieldOff aria-hidden="true" className="size-4" />
                    Slå av 2FA
                  </Button>
                </>
              ) : (
                <>
                  <p className="text-sm leading-relaxed text-muted-foreground text-pretty">
                    Ikke aktivert. Anbefales for organisasjonseiere/administratorer -- da vil du
                    bli bedt om å sette det opp ved neste innlogging uansett.
                  </p>
                  <Button
                    type="button"
                    onClick={() => setSettingUp2fa(true)}
                    className="h-12 w-fit rounded-2xl font-semibold"
                  >
                    <KeyRound aria-hidden="true" className="size-4" />
                    Sett opp 2FA
                  </Button>
                </>
              )}
            </section>
          </div>
        )}
      </main>
    </div>
  )
}

function PasswordSection({ hasPassword, onChanged }: { hasPassword: boolean; onChanged: () => void }) {
  const [password, setPassword] = useState("")
  const [submitting, setSubmitting] = useState(false)
  const [error, setError] = useState<string | null>(null)
  const [success, setSuccess] = useState(false)

  async function handleSubmit(e: React.FormEvent) {
    e.preventDefault()
    if (password.length < 8 || submitting) return
    setSubmitting(true)
    setError(null)
    setSuccess(false)
    try {
      const res = await fetch("/auth/set-password", {
        method: "POST",
        headers: { "Content-Type": "application/json" },
        credentials: "include",
        body: JSON.stringify({ password }),
      })
      if (!res.ok) {
        const body = await res.json().catch(() => null)
        throw new Error(body?.detail?.message ?? "Klarte ikke å sette passordet.")
      }
      setPassword("")
      setSuccess(true)
      onChanged()
    } catch (err) {
      setError(err instanceof Error ? err.message : "Noe gikk galt. Prøv igjen.")
    } finally {
      setSubmitting(false)
    }
  }

  async function handleRemove() {
    if (!confirm("Fjerne passordet? Du kan fortsatt logge inn med magic-link.")) return
    const res = await fetch("/auth/remove-password", { method: "POST", credentials: "include" })
    if (res.ok) onChanged()
  }

  return (
    <section className="flex flex-col gap-4 rounded-3xl border border-border bg-card p-5 shadow-sm shadow-black/5 sm:p-6">
      <div className="flex items-center gap-2.5">
        <div className="flex size-10 items-center justify-center rounded-xl bg-primary/15">
          <Lock aria-hidden="true" className="size-5 text-primary" />
        </div>
        <h2 className="text-base font-bold text-foreground">Passord</h2>
      </div>

      <p className="text-sm leading-relaxed text-muted-foreground text-pretty">
        {hasPassword
          ? "Du har et passord satt. Du kan fortsatt logge inn med magic-link når som helst."
          : "Ikke satt -- du logger i dag kun inn med magic-link. Passord er et valgfritt tillegg, aldri påkrevd."}
      </p>

      <form onSubmit={handleSubmit} className="flex flex-col gap-3 sm:flex-row sm:items-end">
        <div className="flex flex-1 flex-col gap-1.5">
          <Label htmlFor="new-password" className="text-sm font-semibold">
            {hasPassword ? "Nytt passord" : "Sett et passord"}
          </Label>
          <Input
            id="new-password"
            type="password"
            autoComplete="new-password"
            placeholder="Minst 8 tegn"
            value={password}
            onChange={(e) => setPassword(e.target.value)}
            className="h-12 rounded-xl"
          />
        </div>
        <Button
          type="submit"
          disabled={password.length < 8 || submitting}
          className="h-12 shrink-0 rounded-xl font-semibold"
        >
          {submitting ? "Lagrer …" : hasPassword ? "Bytt passord" : "Sett passord"}
        </Button>
      </form>

      {error && <p className="text-sm font-medium text-destructive">{error}</p>}
      {success && <p className="text-sm font-medium text-primary">Passordet er oppdatert.</p>}

      {hasPassword && (
        <button
          type="button"
          onClick={handleRemove}
          className="w-fit text-sm font-semibold text-muted-foreground transition-colors hover:text-destructive"
        >
          Fjern passordet
        </button>
      )}
    </section>
  )
}