import { useCallback, useEffect, useState } from 'react';
import { KeyRound, Loader2, RefreshCw } from 'lucide-react';
import { useClient } from 'hooks/useClient';
import { toneFill, toneText, type Tone } from '@/components/Data';

// The whole /vault screen: point this install at a Vaultwarden, and see whether it answers.
//
// There is no cipher list here and there will not be one. The vault is end-to-end encrypted and this
// plugin is a credential broker plus a reverse-proxy — the things that read vault items are the Bitwarden
// apps and Officer's own mobile client, both of which hold the keys this server never sees.
//
// Every colour is a semantic token (see components/Data/tone.ts). A plugin that reaches for a palette
// class stops following the theme, which is the one rule `plugins/EXTRACTING-A-PLUGIN.md` states twice.

type VaultConfig = {
  url: string | null;
  enabled: boolean;
  updatedAt: string | null;
  configured: boolean;
};

type HealthResult = {
  ok: boolean;
  error?: string;
  upstreamStatus?: number;
  ms?: number;
  url?: string;
  /** `server.name` from Vaultwarden's own `/api/config`, or null if it did not identify itself. */
  server?: string | null;
  version?: string | null;
  /** Answered 200 AND said it is a Vaultwarden. False means something else is on that address. */
  identified?: boolean;
};

const Field = ({ label, children }: { label: string; children: React.ReactNode }) => (
  <label className="flex flex-col gap-1.5">
    <span className="text-xs font-medium uppercase tracking-wide text-muted-foreground">{label}</span>
    {children}
  </label>
);

const Pill = ({ tone, children }: { tone: Tone; children: React.ReactNode }) => (
  <span className={`rounded-full px-2 py-0.5 text-xs font-medium ${toneFill[tone]}`}>{children}</span>
);

export const VaultPanel = () => {
  const { get, put } = useClient();

  const [config, setConfig] = useState<VaultConfig | null>(null);
  const [url, setUrl] = useState('');
  const [loading, setLoading] = useState(true);
  const [saving, setSaving] = useState(false);
  const [error, setError] = useState<string | null>(null);
  const [health, setHealth] = useState<HealthResult | null>(null);
  const [probing, setProbing] = useState(false);

  const loadConfig = useCallback(async () => {
    try {
      const next = await get<VaultConfig>('/vault/config');
      setConfig(next);
      setUrl(next.url ?? '');
      setError(null);
    } catch (err) {
      setError(err instanceof Error ? err.message : 'could not read the vault configuration');
    } finally {
      setLoading(false);
    }
  }, [get]);

  // Never throws: an unreachable vault is the thing this panel exists to SHOW, not an error state for the
  // panel itself. A rejected probe becomes a result with `ok: false`, same as a 502 body would.
  const probe = useCallback(async () => {
    setProbing(true);
    try {
      setHealth(await get<HealthResult>('/vault/config/health'));
    } catch (err) {
      setHealth({ ok: false, error: err instanceof Error ? err.message : 'probe failed' });
    } finally {
      setProbing(false);
    }
  }, [get]);

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

  // Only probe once there is somewhere to probe. Asking about an unconfigured vault returns a 503 that
  // reads on screen as a fault, when the honest answer is "you have not set this up yet".
  useEffect(() => {
    if (config?.configured) void probe();
  }, [config?.configured, probe]);

  const save = async () => {
    setSaving(true);
    setError(null);
    try {
      const next = await put<VaultConfig>('/vault/config', { url: url.trim() || null });
      setConfig(next);
      setUrl(next.url ?? '');
      // The sidecar re-reads its cached URL on a 10s TTL (see sidecar/upstream.ts), so a probe fired
      // immediately would still be answered against the OLD upstream and look like the save failed.
      setHealth(null);
      setTimeout(() => void probe(), 10_500);
    } catch (err) {
      setError(err instanceof Error ? err.message : 'could not save');
    } finally {
      setSaving(false);
    }
  };

  const toggleEnabled = async () => {
    if (!config) return;
    setSaving(true);
    setError(null);
    try {
      setConfig(await put<VaultConfig>('/vault/config', { enabled: !config.enabled }));
      setHealth(null);
      setTimeout(() => void probe(), 10_500);
    } catch (err) {
      setError(err instanceof Error ? err.message : 'could not save');
    } finally {
      setSaving(false);
    }
  };

  if (loading) {
    return (
      <div className="flex h-full items-center justify-center text-sm text-muted-foreground">
        <Loader2 className="mr-2 h-4 w-4 animate-spin" />
        Loading…
      </div>
    );
  }

  const dirty = (config?.url ?? '') !== url.trim();

  const statusTone: Tone = !config?.configured ? 'neutral' : !config.enabled ? 'warning' : health?.ok ? 'success' : health ? 'danger' : 'busy';
  const statusLabel = !config?.configured
    ? 'Not configured'
    : !config.enabled
      ? 'Disabled'
      : health?.ok
        ? 'Reachable'
        : health
          ? 'Unreachable'
          : 'Checking…';

  return (
    <div className="h-full overflow-y-auto">
      <div className="mx-auto flex max-w-2xl flex-col gap-6 p-6">
        <header className="flex items-start gap-3">
          <div className="flex h-10 w-10 shrink-0 items-center justify-center rounded-xl bg-muted">
            <KeyRound className="h-5 w-5 text-muted-foreground" />
          </div>
          <div className="min-w-0 flex-1">
            <div className="flex items-center gap-2">
              <h1 className="text-lg font-semibold">Vault</h1>
              <Pill tone={statusTone}>{statusLabel}</Pill>
            </div>
            <p className="mt-1 text-sm text-muted-foreground">
              Point Officer at a Vaultwarden you already run. Officer holds the vault session so your
              devices never have to — they sign in to Officer instead.
            </p>
          </div>
        </header>

        <section className="flex flex-col gap-4 rounded-xl border border-border p-4">
          <Field label="Vaultwarden URL">
            <input
              value={url}
              onChange={(ev) => setUrl(ev.target.value)}
              onKeyDown={(ev) => {
                if (ev.key === 'Enter' && dirty && !saving) void save();
              }}
              placeholder="https://vault.example.com"
              spellCheck={false}
              autoCapitalize="none"
              className="w-full rounded-lg border border-border bg-background px-3 py-2 text-sm outline-none focus:border-primary"
            />
          </Field>

          <p className="text-xs text-muted-foreground">
            The address of your own Vaultwarden server. Officer never installs or manages it — it forwards
            to it, and stores nothing from inside it.
          </p>

          {error && <p className={`text-sm ${toneText.danger}`}>{error}</p>}

          <div className="flex items-center gap-2">
            <button
              type="button"
              onClick={() => void save()}
              disabled={!dirty || saving}
              className="rounded-lg bg-primary px-3 py-1.5 text-xs font-medium text-primary-foreground transition-opacity hover:opacity-90 disabled:opacity-40"
            >
              {saving ? 'Saving…' : 'Save'}
            </button>
            {dirty && !saving && (
              <button
                type="button"
                onClick={() => setUrl(config?.url ?? '')}
                className="rounded-lg px-3 py-1.5 text-xs text-muted-foreground hover:text-foreground"
              >
                Cancel
              </button>
            )}
            {config?.configured && (
              <button
                type="button"
                onClick={() => void toggleEnabled()}
                disabled={saving}
                className="ml-auto rounded-lg border border-border px-3 py-1.5 text-xs text-muted-foreground transition-colors hover:text-foreground disabled:opacity-40"
              >
                {config.enabled ? 'Disable' : 'Enable'}
              </button>
            )}
          </div>
        </section>

        {config?.configured && (
          <section className="flex flex-col gap-3 rounded-xl border border-border p-4">
            <div className="flex items-center justify-between">
              <span className="text-sm font-medium">Connection</span>
              <button
                type="button"
                onClick={() => void probe()}
                disabled={probing}
                className="flex items-center gap-1.5 rounded-lg px-2 py-1 text-xs text-muted-foreground transition-colors hover:text-foreground disabled:opacity-40"
              >
                <RefreshCw className={`h-3.5 w-3.5 ${probing ? 'animate-spin' : ''}`} />
                Check
              </button>
            </div>

            {health ? (
              <div className="flex flex-col gap-1 text-xs text-muted-foreground">
                <div className="flex items-center gap-2">
                  {/* Three outcomes, not two. "Answered but is not a Vaultwarden" is its own state and the
                      main reason this check exists — pointing at the wrong port on a busy host gives a
                      perfectly good 200 from something that can never serve a vault. */}
                  <Pill tone={health.ok ? (health.identified ? 'success' : 'warning') : 'danger'}>
                    {health.ok ? (health.identified ? 'Vaultwarden' : 'Answered, but not a Vaultwarden') : 'No answer'}
                  </Pill>
                  {health.version && <span>v{health.version}</span>}
                  {health.ms !== undefined && <span>{health.ms}ms</span>}
                  {health.upstreamStatus !== undefined && <span>HTTP {health.upstreamStatus}</span>}
                </div>
                {health.ok && !health.identified && (
                  <span className={toneText.warning}>
                    Something is listening there, but it did not identify itself as a Vaultwarden. Check the
                    port.
                  </span>
                )}
                {health.error && <span className={toneText.danger}>{health.error}</span>}
              </div>
            ) : (
              <span className="text-xs text-muted-foreground">
                {probing ? 'Checking…' : 'Not checked since the last change.'}
              </span>
            )}
          </section>
        )}
      </div>
    </div>
  );
};