"use client"

import { useRouter } from "next/navigation"
import { useState, useSyncExternalStore, useTransition } from "react"
import { CopyPlusIcon, DownloadIcon, ExternalLinkIcon, RefreshCwIcon, Trash2Icon } from "lucide-react"
import { Button, buttonVariants } from "@/components/ui/button"
import { CopyField } from "@/modules/admin/ui/components/copy-field"
import { deleteVariant, duplicateVariant, updateShare } from "../../../actions/variants"
import { dateFormat, SHARE_EXPIRY_OPTIONS } from "../../../lib/preview"
import type { EditorVariant } from "../../views/variant-editor"

const selectClass = "h-10 w-full rounded-md border bg-background px-3 text-sm outline-none focus-visible:ring-3 focus-visible:ring-ring/50"
const subscribe = () => () => {}

function Heading({ title, text }: { title: string; text?: string }) {
    return (
        <div className="mb-3">
            <h3 className="text-sm font-medium">{title}</h3>
            {text && <p className="mt-0.5 text-xs text-muted-foreground">{text}</p>}
        </div>
    )
}

export function SharePanel({ variant, clients, clientId, onClientChange, dirty }: {
    variant: EditorVariant
    clients: { id: string; name: string }[]
    clientId: string | null
    onClientChange: (clientId: string | null) => void
    dirty: boolean
}) {
    const router = useRouter()
    const origin = useSyncExternalStore(subscribe, () => window.location.origin, () => "")
    const [share, setShare] = useState({ token: variant.shareToken, expiresAt: variant.shareExpiresAt, expired: variant.shareState === "expired" })
    // -1 = bestehendes Ablaufdatum beibehalten
    const [expiry, setExpiry] = useState<number>(variant.shareExpiresAt ? -1 : 0)
    const [confirmDelete, setConfirmDelete] = useState(false)
    const [exporting, setExporting] = useState(false)
    const [error, setError] = useState<string | null>(null)
    const [pending, startTransition] = useTransition()

    function run(action: () => Promise<{ error: string } | unknown>) {
        startTransition(async () => {
            const result = await action()
            if (result && typeof result === "object" && "error" in result) setError(String(result.error))
            else setError(null)
        })
    }

    function applyShare(enabled: boolean, options: { regenerate?: boolean; days?: number } = {}) {
        run(async () => {
            const days = options.days ?? (expiry < 0 ? 0 : expiry)
            const result = await updateShare(variant.id, { enabled, expiresInDays: days, regenerate: options.regenerate })
            if (!("error" in result)) {
                setShare({ ...result, expired: false })
                setExpiry(result.expiresAt ? days : 0)
            }
            return result
        })
    }

    async function exportProject() {
        setExporting(true)
        try {
            const response = await fetch(`/api/templates/${variant.id}/export`)
            if (!response.ok) {
                const body = await response.json().catch(() => null)
                setError(body?.error ?? "Export fehlgeschlagen.")
                return
            }
            const fileName = /filename="([^"]+)"/.exec(response.headers.get("Content-Disposition") ?? "")?.[1] ?? "website.zip"
            const link = document.createElement("a")
            link.href = URL.createObjectURL(await response.blob())
            link.download = fileName
            link.click()
            URL.revokeObjectURL(link.href)
            setError(null)
        } catch {
            setError("Export fehlgeschlagen.")
        } finally {
            setExporting(false)
        }
    }

    const url = share.token ? `${origin}/demo/${share.token}` : ""

    return (
        <div className="flex flex-col gap-8">
            <section>
                <Heading title="Client" text="Optional – ordnet die Variante einem Kunden zu. Wird mit „Speichern“ übernommen." />
                <select
                    value={clientId ?? ""}
                    onChange={(event) => onClientChange(event.target.value || null)}
                    className={selectClass}
                    aria-label="Client"
                >
                    <option value="">Kein Client (Pitch)</option>
                    {clients.map((client) => (
                        <option key={client.id} value={client.id}>{client.name}</option>
                    ))}
                </select>
            </section>

            <section>
                <Heading title="Link teilen" text="Kunden öffnen den Link ohne Login. Er zeigt immer den zuletzt gespeicherten Stand." />
                {share.token ? (
                    <div className="flex flex-col gap-3">
                        {share.expired && (
                            <p className="rounded-md bg-signal-warning/12 px-3 py-2 text-xs text-signal-warning">
                                Dieser Link ist abgelaufen. Wähle eine neue Gültigkeit, um ihn wieder zu aktivieren.
                            </p>
                        )}
                        <CopyField label="Öffentlicher Link" value={url} />
                        <label className="flex flex-col gap-1.5 text-sm">
                            Gültigkeit
                            <select
                                value={expiry}
                                disabled={pending}
                                onChange={(event) => applyShare(true, { days: Number(event.target.value) })}
                                className={selectClass}
                            >
                                {expiry < 0 && share.expiresAt && (
                                    <option value={-1}>bis {dateFormat.format(new Date(share.expiresAt))}</option>
                                )}
                                {SHARE_EXPIRY_OPTIONS.map((option) => (
                                    <option key={option.days} value={option.days}>{option.label}</option>
                                ))}
                            </select>
                        </label>
                        <div className="flex flex-wrap gap-2">
                            <a href={url} target="_blank" rel="noreferrer" className={buttonVariants({ variant: "outline", size: "sm" })}>
                                <ExternalLinkIcon /> Öffnen
                            </a>
                            <Button variant="outline" size="sm" disabled={pending} onClick={() => applyShare(true, { regenerate: true })}>
                                <RefreshCwIcon /> Neuer Link
                            </Button>
                            <Button variant="ghost" size="sm" disabled={pending} onClick={() => applyShare(false)}>
                                Freigabe beenden
                            </Button>
                        </div>
                        <p className="text-xs text-muted-foreground">„Neuer Link“ macht den bisherigen Link ungültig.</p>
                    </div>
                ) : (
                    <Button disabled={pending} onClick={() => applyShare(true)}>Link erstellen</Button>
                )}
            </section>

            <section>
                <Heading
                    title="Als Next.js-Projekt exportieren"
                    text="Eigenständiges Projekt (ZIP) mit Vorlage, Inhalten und eigenen Bildern – ohne Entwurfs-Hinweis und KI-Funktionen. Die README listet, was vor dem Livegang noch fehlt."
                />
                <Button variant="outline" className="w-full" disabled={exporting} onClick={exportProject}>
                    <DownloadIcon /> {exporting ? "Wird erstellt …" : "ZIP herunterladen"}
                </Button>
                {dirty && <p className="mt-2 text-xs text-muted-foreground">Exportiert wird der gespeicherte Stand.</p>}
            </section>

            <section>
                <Heading title="Variante" />
                <div className="flex flex-col gap-2">
                    <Button variant="outline" disabled={pending} onClick={() => run(() => duplicateVariant(variant.id))}>
                        <CopyPlusIcon /> Duplizieren
                    </Button>
                    {dirty && <p className="text-xs text-muted-foreground">Dupliziert wird der gespeicherte Stand.</p>}
                    {confirmDelete ? (
                        <div className="flex gap-2">
                            <Button
                                variant="destructive"
                                className="flex-1"
                                disabled={pending}
                                onClick={() =>
                                    run(async () => {
                                        const result = await deleteVariant(variant.id)
                                        if ("success" in result) router.push("/admin/templates")
                                        return result
                                    })
                                }
                            >
                                Endgültig löschen
                            </Button>
                            <Button variant="outline" onClick={() => setConfirmDelete(false)}>Abbrechen</Button>
                        </div>
                    ) : (
                        <Button variant="ghost" className="text-destructive" onClick={() => setConfirmDelete(true)}>
                            <Trash2Icon /> Löschen
                        </Button>
                    )}
                </div>
            </section>

            {error && <p className="text-sm text-destructive">{error}</p>}
        </div>
    )
}