"use client"

import { useState, useTransition } from "react"
import { toast } from "sonner"
import { Sparkles, Check, AlertTriangle } from "lucide-react"
import { setAiProviderAction } from "@/app/actions/admin"

type Provider = "openai" | "anthropic"

const LABELS: Record<Provider, string> = { openai: "OpenAI", anthropic: "Anthropic (Claude)" }

export function AiProviderToggle({
  selected,
  effective,
  openaiConfigured,
  anthropicConfigured,
  openaiModel,
  anthropicModel,
}: {
  selected: Provider
  effective: Provider
  openaiConfigured: boolean
  anthropicConfigured: boolean
  openaiModel: string
  anthropicModel: string
}) {
  const [current, setCurrent] = useState<Provider>(selected)
  const [pending, startTransition] = useTransition()

  const configured: Record<Provider, boolean> = { openai: openaiConfigured, anthropic: anthropicConfigured }
  const models: Record<Provider, string> = { openai: openaiModel, anthropic: anthropicModel }

  function choose(next: Provider) {
    if (next === current || pending) return
    const prev = current
    setCurrent(next)
    startTransition(async () => {
      try {
        await setAiProviderAction(next)
        toast.success(`AI provider set to ${LABELS[next]}`)
      } catch {
        setCurrent(prev) // revert optimistic change
        toast.error("Couldn't switch the AI provider. Try again.")
      }
    })
  }

  // When the selected provider has no key on the server, AI falls back to the
  // other configured provider (see lib/ai/provider). Surface that clearly.
  const fallbackActive = effective !== current
  const noneConfigured = !openaiConfigured && !anthropicConfigured

  const options: Provider[] = ["openai", "anthropic"]

  return (
    <div className="rounded-2xl border border-white/[0.06] bg-[#16161f] overflow-hidden">
      <div className="flex items-center gap-2 border-b border-white/[0.06] px-5 py-4">
        <Sparkles className="h-4 w-4 text-rose-400 shrink-0" />
        <h2 className="text-sm font-semibold text-white">AI provider</h2>
      </div>

      <div className="px-5 py-4 space-y-3">
        <p className="text-xs text-white/40">
          Choose which LLM powers all AI features (assistant, recommendations, predictions, summaries,
          receipts). Applies to everyone immediately.
        </p>

        <div className="grid gap-2 sm:grid-cols-2">
          {options.map((p) => {
            const active = current === p
            return (
              <button
                key={p}
                type="button"
                onClick={() => choose(p)}
                disabled={pending}
                aria-pressed={active}
                className={`flex items-start justify-between gap-3 rounded-xl border px-4 py-3 text-left transition disabled:opacity-60 ${
                  active
                    ? "border-rose-500/40 bg-rose-500/[0.08]"
                    : "border-white/10 bg-white/[0.02] hover:bg-white/[0.05]"
                }`}
              >
                <div className="min-w-0">
                  <div className="flex items-center gap-2">
                    <span className="text-sm font-semibold text-white">{LABELS[p]}</span>
                    {active && <Check className="h-3.5 w-3.5 text-rose-400" />}
                  </div>
                  <p className="mt-0.5 font-mono text-[11px] text-white/40 truncate">{models[p]}</p>
                  <p className="mt-1 text-[11px]">
                    {configured[p] ? (
                      <span className="text-emerald-400">API key configured</span>
                    ) : (
                      <span className="text-amber-400">No API key on server</span>
                    )}
                  </p>
                </div>
              </button>
            )
          })}
        </div>

        {noneConfigured ? (
          <p className="flex items-start gap-1.5 rounded-lg border border-amber-500/20 bg-amber-500/[0.06] px-3 py-2 text-[11px] text-amber-300/90">
            <AlertTriangle className="mt-0.5 h-3 w-3 shrink-0" />
            No AI provider key is set on the server — AI features return a 503 until{" "}
            <code className="font-mono">OPENAI_API_KEY</code> or <code className="font-mono">ANTHROPIC_API_KEY</code> is configured.
          </p>
        ) : fallbackActive ? (
          <p className="flex items-start gap-1.5 rounded-lg border border-amber-500/20 bg-amber-500/[0.06] px-3 py-2 text-[11px] text-amber-300/90">
            <AlertTriangle className="mt-0.5 h-3 w-3 shrink-0" />
            {LABELS[current]} has no API key on this server, so AI is temporarily running on{" "}
            <span className="font-semibold">{LABELS[effective]}</span>. Add the key to use {LABELS[current]}.
          </p>
        ) : null}
      </div>
    </div>
  )
}