"use client";

import { useEffect, useState } from "react";

const API_BASE_URL =
  process.env.NEXT_PUBLIC_API_BASE_URL ?? "";

type MerchantAdminDto = {
  id: number;
  name: string;
  avantlinkMid: string;
  feedUrl: string;
  offerFeedUrl: string | null;
  isActive: boolean;
  lastFullImportAt: string | null;
  lastOfferSyncAt: string | null;
};

function formatDate(value: string | null) {
  if (!value) return "—";
  const d = new Date(value);
  if (Number.isNaN(d.getTime())) return value;
  return d.toLocaleString();
}

export default function MerchantsAdminPage() {
  const [merchants, setMerchants] = useState<MerchantAdminDto[]>([]);
  const [loading, setLoading] = useState(true);
  const [error, setError] = useState<string | null>(null);
  const [savingId, setSavingId] = useState<number | null>(null);
  const [importingId, setImportingId] = useState<number | null>(null);
  const [offerSyncId, setOfferSyncId] = useState<number | null>(null);
  const [banner, setBanner] = useState<string | null>(null);

  // --- load merchants ---
  useEffect(() => {
    const controller = new AbortController();

    async function loadMerchants() {
      try {
        setLoading(true);
        setError(null);

        const url = `${API_BASE_URL}/api/admin/merchants`;
        console.log("Loading merchants from:", url);

        const res = await fetch(url, {
          method: "GET",
          headers: { Accept: "application/json" },
          signal: controller.signal,
        });

        if (!res.ok) {
          const text = await res.text().catch(() => "");
          throw new Error(`HTTP ${res.status} ${res.statusText} – ${text}`);
        }

        const data: MerchantAdminDto[] = await res.json();
        setMerchants(data);
      } catch (err: any) {
        if (err?.name === "AbortError") return;
        console.error("Error loading merchants", err);
        setError(err?.message ?? "Failed to load merchants");
      } finally {
        setLoading(false);
      }
    }

    loadMerchants();
    return () => controller.abort();
  }, []);

  // --- local field editing ---
  const updateMerchantField = <K extends keyof MerchantAdminDto>(
    id: number,
    field: K,
    value: MerchantAdminDto[K]
  ) => {
    setMerchants((prev) =>
      prev.map((m) => (m.id === id ? { ...m, [field]: value } : m))
    );
  };

  // --- save merchant (name/feed URLs/isActive) ---
  const handleSave = async (id: number) => {
    const merchant = merchants.find((m) => m.id === id);
    if (!merchant) return;

    try {
      setSavingId(id);
      setError(null);
      setBanner(null);

      const res = await fetch(`${API_BASE_URL}/api/admin/merchants/${id}`, {
        method: "PUT",
        headers: { "Content-Type": "application/json" },
        body: JSON.stringify({
          name: merchant.name,
          avantlinkMid: merchant.avantlinkMid,
          feedUrl: merchant.feedUrl,
          offerFeedUrl: merchant.offerFeedUrl,
          isActive: merchant.isActive,
        }),
      });

      if (!res.ok) {
        const text = await res.text().catch(() => "");
        console.error("Merchant save failed", res.status, text);
        throw new Error(`Save failed (${res.status})${text ? `: ${text}` : ""}`);
      }

      const updated: MerchantAdminDto = await res.json();
      setMerchants((prev) => prev.map((m) => (m.id === id ? updated : m)));

      setBanner("Merchant saved successfully.");
    } catch (e: any) {
      console.error("Error saving merchant", e);
      setError(e?.message ?? "Failed to save merchant");
    } finally {
      setSavingId(null);
      setTimeout(() => setBanner(null), 3000);
    }
  };

  // --- run full import ---
  const handleRunFullImport = async (id: number) => {
    try {
      setImportingId(id);
      setError(null);
      setBanner(null);

      const res = await fetch(`${API_BASE_URL}/api/admin/imports/${id}`, {
        method: "POST",
      });

      if (!res.ok) {
        const text = await res.text().catch(() => "");
        console.error("Full import failed", res.status, text);
        throw new Error(`Import failed (${res.status})${text ? `: ${text}` : ""}`);
      }

      setBanner("Full import started successfully.");
    } catch (e: any) {
      console.error("Error starting full import", e);
      setError(e?.message ?? "Failed to start full import");
    } finally {
      setImportingId(null);
      setTimeout(() => setBanner(null), 3000);
    }
  };

  // --- run offer sync ---
  const handleRunOfferSync = async (id: number) => {
    try {
      setOfferSyncId(id);
      setError(null);
      setBanner(null);

      const res = await fetch(
        `${API_BASE_URL}/api/admin/imports/${id}/offers-only`,
        { method: "POST" }
      );

      if (!res.ok) {
        const text = await res.text().catch(() => "");
        console.error("Offer sync failed", res.status, text);
        throw new Error(
          `Offer sync failed (${res.status})${text ? `: ${text}` : ""}`
        );
      }

      setBanner("Offer sync started successfully.");
    } catch (e: any) {
      console.error("Error starting offer sync", e);
      setError(e?.message ?? "Failed to start offer sync");
    } finally {
      setOfferSyncId(null);
      setTimeout(() => setBanner(null), 3000);
    }
  };

  return (
    <main className="min-h-screen bg-black text-zinc-50">
      <div className="mx-auto max-w-6xl px-4 py-6 lg:py-10">
        {/* Header */}
        <header className="mb-6 flex items-center justify-between gap-4">
          <div>
            <p className="text-xs font-semibold tracking-[0.2em] uppercase text-zinc-500">
              Shadow Standard
            </p>
            <h1 className="mt-1 text-2xl md:text-3xl font-semibold tracking-tight">
              Merchant Feeds <span className="text-amber-300">Admin</span>
            </h1>
            <p className="mt-2 text-sm text-zinc-400 max-w-2xl">
              Manage your AvantLink merchants, product feed URLs, and offer sync
              settings. Use this to onboard new merchants and keep feeds fresh
              without touching SQL.
            </p>
          </div>
        </header>

        {/* Status banners */}
        {banner && (
          <div className="mb-4 rounded-md border border-emerald-500/40 bg-emerald-500/10 px-3 py-2 text-sm text-emerald-200">
            {banner}
          </div>
        )}
        {error && (
          <div className="mb-4 rounded-md border border-red-500/40 bg-red-500/10 px-3 py-2 text-sm text-red-200">
            {error}
          </div>
        )}

        {/* Table */}
        <section className="rounded-lg border border-zinc-800 bg-zinc-950/70 p-3 md:p-4">
          {loading ? (
            <p className="text-sm text-zinc-500">Loading merchants…</p>
          ) : merchants.length === 0 ? (
            <p className="text-sm text-zinc-500">
              No merchants found. Seed some merchants in the backend.
            </p>
          ) : (
            <div className="overflow-x-auto">
              <table className="min-w-full text-left text-sm">
                <thead>
                  <tr className="border-b border-zinc-800 text-xs uppercase tracking-[0.16em] text-zinc-500">
                    <th className="py-2 pr-3">Merchant</th>
                    <th className="py-2 px-3">AvantLink MID</th>
                    <th className="py-2 px-3">Feed URL</th>
                    <th className="py-2 px-3">Offer Feed URL</th>
                    <th className="py-2 px-3">Active</th>
                    <th className="py-2 px-3">Last Full Import</th>
                    <th className="py-2 px-3">Last Offer Sync</th>
                    <th className="py-2 pl-3 text-right">Actions</th>
                  </tr>
                </thead>

                <tbody className="divide-y divide-zinc-800">
                  {merchants.map((m) => (
                    <tr key={m.id} className="align-top">
                      <td className="py-2 pr-3">
                        <input
                          type="text"
                          value={m.name}
                          onChange={(e) =>
                            updateMerchantField(m.id, "name", e.target.value)
                          }
                          className="w-full rounded-md border border-zinc-700 bg-zinc-900 px-2 py-1 text-sm text-zinc-50 focus:border-amber-400/70 focus:outline-none focus:ring-0"
                        />
                      </td>

                      <td className="py-2 px-3">
                        <input
                          type="text"
                          value={m.avantlinkMid}
                          onChange={(e) =>
                            updateMerchantField(m.id, "avantlinkMid", e.target.value)
                          }
                          className="w-full rounded-md border border-zinc-700 bg-zinc-900 px-2 py-1 text-sm text-zinc-50 focus:border-amber-400/70 focus:outline-none focus:ring-0"
                        />
                      </td>

                      <td className="py-2 px-3">
                        <input
                          type="text"
                          value={m.feedUrl ?? ""}
                          onChange={(e) =>
                            updateMerchantField(m.id, "feedUrl", e.target.value)
                          }
                          className="w-full rounded-md border border-zinc-700 bg-zinc-900 px-2 py-1 text-xs md:text-sm text-zinc-50 focus:border-amber-400/70 focus:outline-none focus:ring-0"
                        />
                      </td>

                      <td className="py-2 px-3">
                        <input
                          type="text"
                          value={m.offerFeedUrl ?? ""}
                          onChange={(e) =>
                            updateMerchantField(m.id, "offerFeedUrl", e.target.value || null)
                          }
                          className="w-full rounded-md border border-zinc-700 bg-zinc-900 px-2 py-1 text-xs md:text-sm text-zinc-50 focus:border-amber-400/70 focus:outline-none focus:ring-0"
                        />
                      </td>

                      <td className="py-2 px-3">
                        <label className="inline-flex items-center gap-2 text-xs text-zinc-300">
                          <input
                            type="checkbox"
                            checked={m.isActive}
                            onChange={(e) =>
                              updateMerchantField(m.id, "isActive", e.target.checked)
                            }
                            className="h-4 w-4 rounded border-zinc-600 bg-zinc-900 text-amber-400 focus:ring-amber-400"
                          />
                          Active
                        </label>
                      </td>

                      <td className="py-2 px-3 text-xs text-zinc-400 whitespace-nowrap">
                        {formatDate(m.lastFullImportAt)}
                      </td>

                      <td className="py-2 px-3 text-xs text-zinc-400 whitespace-nowrap">
                        {formatDate(m.lastOfferSyncAt)}
                      </td>

                      <td className="py-2 pl-3">
                        <div className="flex flex-col items-end gap-1">
                          <button
                            type="button"
                            onClick={() => handleSave(m.id)}
                            disabled={savingId === m.id}
                            className={`rounded-md px-3 py-1.5 text-xs font-medium transition-colors ${
                              savingId === m.id
                                ? "bg-amber-400/20 text-amber-200 cursor-wait"
                                : "bg-amber-400 text-black hover:bg-amber-300"
                            }`}
                          >
                            {savingId === m.id ? "Saving…" : "Save"}
                          </button>

                          <button
                            type="button"
                            onClick={() => handleRunFullImport(m.id)}
                            disabled={importingId === m.id}
                            className={`rounded-md px-3 py-1.5 text-xs font-medium border border-zinc-700 bg-zinc-900 text-zinc-200 hover:bg-zinc-800 transition-colors ${
                              importingId === m.id ? "opacity-60 cursor-wait" : ""
                            }`}
                          >
                            {importingId === m.id ? "Importing…" : "Run Full Import"}
                          </button>

                          <button
                            type="button"
                            onClick={() => handleRunOfferSync(m.id)}
                            disabled={offerSyncId === m.id}
                            className={`rounded-md px-3 py-1.5 text-xs font-medium border border-zinc-700 bg-zinc-900 text-zinc-200 hover:bg-zinc-800 transition-colors ${
                              offerSyncId === m.id ? "opacity-60 cursor-wait" : ""
                            }`}
                          >
                            {offerSyncId === m.id ? "Syncing Offers…" : "Run Offer Sync"}
                          </button>
                        </div>
                      </td>
                    </tr>
                  ))}
                </tbody>
              </table>
            </div>
          )}
        </section>
      </div>
    </main>
  );
}