import { Eye, EyeOff } from "lucide-react";
import { useEffect, useState } from "react";
import { Link, Navigate } from "react-router-dom";

import { Button, Field, Spinner, inputClass } from "@/components/ui";
import { errorMessage } from "@/lib/api";
import { hasBackend } from "@/lib/backend";
import { cn } from "@/lib/cn";
import {
  e621ErrorMessage,
  verifyE621Credentials,
  type E621Credentials,
} from "@/lib/e621";
import { useAuth } from "@/store/auth";
import { useE621 } from "@/store/e621";
import { toast } from "@/store/toasts";

import { AvatarCard } from "./AvatarCard";
import { PreferencesCard } from "./PreferencesCard";
import { TokensCard } from "./TokensCard";

const BASE_URL_OPTIONS = [
  { value: "https://e621.net", label: "e621.net — main site" },
  { value: "https://e926.net", label: "e926.net — safe mirror" },
  { value: "custom", label: "Custom…" },
];

function AccountForm({ credentials }: { credentials: E621Credentials | null }) {
  const save = useE621((state) => state.save);

  const [username, setUsername] = useState(credentials?.username ?? "");
  const [apiKey, setApiKey] = useState(credentials?.api_key ?? "");
  const savedBase = credentials?.base_url ?? "https://e621.net";
  const savedBaseIsKnown = BASE_URL_OPTIONS.some(
    (option) => option.value === savedBase,
  );
  const [baseChoice, setBaseChoice] = useState(
    savedBaseIsKnown ? savedBase : "custom",
  );
  const [customBase, setCustomBase] = useState(savedBaseIsKnown ? "" : savedBase);
  const [showKey, setShowKey] = useState(false);
  const [saving, setSaving] = useState(false);
  const [testing, setTesting] = useState(false);

  const baseUrl = (baseChoice === "custom" ? customBase.trim() : baseChoice).replace(
    /\/+$/,
    "",
  );
  const values = {
    username: username.trim(),
    api_key: apiKey.trim(),
    base_url: baseUrl,
  };

  async function handleSave() {
    setSaving(true);
    try {
      await save(values);
      toast.ok("e621 credentials saved.");
    } catch (error) {
      toast.error(errorMessage(error));
    } finally {
      setSaving(false);
    }
  }

  async function handleTest() {
    setTesting(true);
    try {
      const user = await verifyE621Credentials({ ...values, configured: true });
      toast.ok(
        `Connected as ${user.name}${
          typeof user.favorite_count === "number"
            ? ` — ${user.favorite_count} favorites`
            : ""
        }.`,
      );
    } catch (error) {
      toast.error(e621ErrorMessage(error));
    } finally {
      setTesting(false);
    }
  }

  return (
    <section className="rounded-lg border border-ctp-surface0 bg-ctp-base p-5">
      <div className="flex items-start justify-between gap-3">
        <div>
          <h2 className="text-sm font-semibold text-ctp-subtext1">
            e621 credentials
          </h2>
          <p className="mt-1 text-xs text-ctp-overlay0">
            Generate an API key under Account → My profile on e621, then paste it
            here.
          </p>
        </div>
        <span
          className={cn(
            "shrink-0 rounded-full border px-2.5 py-1 font-mono text-[11px]",
            credentials?.configured
              ? "border-ctp-green/40 bg-ctp-green/15 text-ctp-green"
              : "border-ctp-surface1 text-ctp-overlay0",
          )}
        >
          {credentials?.configured ? "Configured" : "Not configured"}
        </span>
      </div>

      <div className="mt-5 flex flex-col gap-4">
        <Field label="e621 username">
          <input
            className={inputClass}
            value={username}
            onChange={(event) => setUsername(event.target.value)}
            autoComplete="off"
          />
        </Field>

        <Field label="API key">
          <div className="relative">
            <input
              className={cn(inputClass, "pr-10 font-mono")}
              type={showKey ? "text" : "password"}
              value={apiKey}
              onChange={(event) => setApiKey(event.target.value)}
              autoComplete="off"
            />
            <button
              type="button"
              onClick={() => setShowKey((visible) => !visible)}
              title={showKey ? "Hide API key" : "Show API key"}
              className="absolute right-2 top-1/2 -translate-y-1/2 rounded p-1 text-ctp-overlay0 transition hover:bg-ctp-surface0 hover:text-ctp-text"
            >
              {showKey ? (
                <EyeOff className="h-4 w-4" />
              ) : (
                <Eye className="h-4 w-4" />
              )}
            </button>
          </div>
        </Field>

        <Field label="API base URL">
          <div className="flex flex-col gap-2">
            <select
              className={inputClass}
              value={baseChoice}
              onChange={(event) => setBaseChoice(event.target.value)}
            >
              {BASE_URL_OPTIONS.map((option) => (
                <option key={option.value} value={option.value}>
                  {option.label}
                </option>
              ))}
            </select>
            {baseChoice === "custom" ? (
              <input
                className={cn(inputClass, "font-mono")}
                placeholder="https://example.com"
                value={customBase}
                onChange={(event) => setCustomBase(event.target.value)}
              />
            ) : null}
          </div>
        </Field>

        <div className="flex items-center gap-3">
          <Button onClick={() => void handleSave()} disabled={saving}>
            {saving ? "Saving…" : "Save"}
          </Button>
          <Button
            variant="secondary"
            onClick={() => void handleTest()}
            disabled={testing || !values.username || !values.api_key}
          >
            {testing ? "Testing…" : "Test connection"}
          </Button>
        </div>

        <p className="text-xs text-ctp-overlay0">
          {hasBackend()
            ? "Stored on your server and fetched by this app when needed. e621 requests are made directly from your browser, throttled to one per second."
            : "Stored in this browser only (local mode). e621 requests are made directly from here, throttled to one per second."}
        </p>
      </div>
    </section>
  );
}

export default function AccountPage() {
  const user = useAuth((state) => state.user);
  const credentials = useE621((state) => state.credentials);
  const loading = useE621((state) => state.loading);
  const load = useE621((state) => state.load);
  const backend = hasBackend();

  useEffect(() => {
    void load();
  }, [load]);

  // Local mode: the e621 credentials live in this browser.
  if (!backend) {
    return (
      <div className="mx-auto flex w-full max-w-2xl flex-col gap-6">
        <header>
          <h1 className="text-lg font-semibold">e621 account</h1>
          <p className="mt-1 text-sm text-ctp-overlay0">
            No backend is connected, so these credentials are stored in this
            browser only and sent straight to e621 from here.
          </p>
        </header>
        {loading && !credentials ? (
          <div className="flex justify-center py-12">
            <Spinner className="h-6 w-6" />
          </div>
        ) : (
          <AccountForm credentials={credentials} />
        )}
        <p className="text-xs text-ctp-overlay0">
          <Link to="/setup" className="text-ctp-blue hover:underline">
            Connect a backend
          </Link>{" "}
          to unlock the library, follows and account settings.
        </p>
      </div>
    );
  }

  if (!user) {
    return <Navigate to="/login" replace />;
  }

  return (
    <div className="mx-auto flex w-full max-w-2xl flex-col gap-6">
      <header>
        <h1 className="text-lg font-semibold">Account</h1>
        <p className="mt-1 flex flex-wrap items-center gap-2 text-sm text-ctp-overlay0">
          <span>Signed in as {user.username}.</span>
          <span className="rounded-full border border-ctp-surface1 px-2 py-0.5 font-mono text-[11px] capitalize text-ctp-subtext0">
            {user.role}
          </span>
          {user.is_superuser ? (
            <span className="rounded-full border border-ctp-red/40 bg-ctp-red/10 px-2 py-0.5 font-mono text-[11px] text-ctp-red">
              admin
            </span>
          ) : null}
        </p>
      </header>
      <AvatarCard />
      <PreferencesCard />
      <TokensCard />
      {loading && !credentials ? (
        <div className="flex justify-center py-12">
          <Spinner className="h-6 w-6" />
        </div>
      ) : (
        <AccountForm credentials={credentials} />
      )}
    </div>
  );
}