import { useCallback, useEffect, useMemo, useState } from "react";

const runtime =
  typeof window !== "undefined" && window.__ENV__ ? window.__ENV__ : {};

const configured = {
  auth: runtime.AUTH_API || import.meta.env.VITE_AUTH_API || "",
  employee: runtime.EMPLOYEE_API || import.meta.env.VITE_EMPLOYEE_API || "",
  transit: runtime.TRANSIT_API || import.meta.env.VITE_TRANSIT_API || "",
  errors: runtime.ERROR_LOG_API || import.meta.env.VITE_ERROR_LOG_API || "",
};

const serviceMeta = {
  auth: {
    label: "Auth API",
    role: "Identity & tokens",
    color: "amber",
    data: "Login, JWT sessions, current user profile",
    routes: ["/login", "/me", "/health"],
    docs: "https://github.com/your-org/auth_api/blob/main/README.md",
  },
  employee: {
    label: "Employee API",
    role: "People operations",
    color: "teal",
    data: "Employee onboarding and employee records",
    routes: ["/health", "/createemployee"],
    docs: "https://github.com/your-org/employee_api/blob/main/README.md",
  },
  transit: {
    label: "Transit API",
    role: "Routes & schedules",
    color: "blue",
    data: "Schedules, routes, GPS, fleet and admin data",
    routes: [
      "/health",
      "/public/schedules/:scheduleId/progress",
      "/schedule/daily?date=YYYY-MM-DD",
      "/admin/stops",
    ],
    docs: "https://github.com/your-org/transit_api/blob/main/README.md",
  },
  errors: {
    label: "Error Log API",
    role: "Incident archive",
    color: "coral",
    data: "Centralized bad requests and service errors",
    routes: ["/health", "/error_log?limit=100"],
    docs: "https://github.com/your-org/error_log_api/blob/main/README.md",
  },
};

const healthPaths = {
  auth: "/health",
  employee: "/health",
  transit: "/health",
  errors: "/health",
};
const testerRoutes = [
  { service: "auth", method: "POST", path: "/login", label: "Login (userCode + password)" },
  { service: "auth", method: "GET", path: "/me", label: "Current session" },
  {
    service: "employee",
    method: "GET",
    path: "/health",
    label: "Employee health",
  },
  {
    service: "transit",
    method: "GET",
    path: "/health",
    label: "Transit health",
  },
  {
    service: "transit",
    method: "GET",
    path: "/public/schedules/1/progress",
    label: "Public schedule progress",
  },
  {
    service: "transit",
    method: "GET",
    path: "/schedule/daily?date=2026-09-20",
    label: "Driver daily schedule",
  },
  {
    service: "errors",
    method: "GET",
    path: "/error_log?limit=25",
    label: "Recent error log",
  },
];

function pretty(value) {
  try {
    return JSON.stringify(value, null, 2);
  } catch {
    return String(value);
  }
}

function App() {
  const [urls, setUrls] = useState(
    () =>
      JSON.parse(localStorage.getItem("transit-monitor-urls") || "null") ||
      configured,
  );
  const [token, setToken] = useState(
    () => localStorage.getItem("transit-monitor-token") || "",
  );
  const [user, setUser] = useState(
    () => JSON.parse(localStorage.getItem("transit-monitor-user") || "null"),
  );
  const [health, setHealth] = useState({});
  const [history, setHistory] = useState({});
  const [errors, setErrors] = useState([]);
  const [errorState, setErrorState] = useState("idle");
  const [interval, setIntervalValue] = useState(30);
  const [lastRefresh, setLastRefresh] = useState(null);
  const [activeView, setActiveView] = useState("overview");
  const [tester, setTester] = useState({
    service: "transit",
    method: "GET",
    path: "/health",
    body: "",
  });
  const [testerResult, setTesterResult] = useState(null);
  const [busy, setBusy] = useState(false);
  const [loginLoading, setLoginLoading] = useState(false);
  const [loginError, setLoginError] = useState("");

  const login = useCallback(async (userCode, password) => {
    const url = urls.auth;
    if (!url) {
      setLoginError("Auth API URL not configured");
      return;
    }
    setLoginLoading(true);
    setLoginError("");
    try {
      const response = await fetch(`${url}/login`, {
        method: "POST",
        headers: { "Content-Type": "application/json" },
        body: JSON.stringify({ userCode, password }),
      });
      const data = await response.json();
      if (!response.ok) {
        throw new Error(data.error || `HTTP ${response.status}`);
      }
      setToken(data.token);
      setUser(data.user);
      localStorage.setItem("transit-monitor-token", data.token);
      localStorage.setItem("transit-monitor-user", JSON.stringify(data.user));
      setLoginError("");
    } catch (error) {
      setLoginError(error.message);
    } finally {
      setLoginLoading(false);
    }
  }, [urls.auth]);

  const logout = useCallback(() => {
    setToken("");
    setUser(null);
    localStorage.removeItem("transit-monitor-token");
    localStorage.removeItem("transit-monitor-user");
  }, []);

  const checkService = useCallback(
    async (key) => {
      const started = performance.now();
      const url = urls[key];
      if (!url) {
        return {
          ok: false,
          status: 0,
          body: { error: "No URL configured" },
          latency: 0,
          checkedAt: new Date().toISOString(),
        };
      }
      const headers = token ? { Authorization: `Bearer ${token}` } : {};
      try {
        const response = await fetch(`${url}${healthPaths[key]}`, {
          headers,
        });
        const body = await response.json().catch(() => null);
        return {
          ok: response.ok,
          status: response.status,
          body,
          latency: Math.round(performance.now() - started),
          checkedAt: new Date().toISOString(),
        };
      } catch (error) {
        return {
          ok: false,
          status: 0,
          body: { error: error.message },
          latency: Math.round(performance.now() - started),
          checkedAt: new Date().toISOString(),
        };
      }
    },
    [token, urls],
  );

  const refreshHealth = useCallback(async () => {
    const results = await Promise.all(
      Object.keys(serviceMeta).map(async (key) => [
        key,
        await checkService(key),
      ]),
    );
    const next = Object.fromEntries(results);
    setHealth(next);
    setHistory((current) =>
      Object.fromEntries(
        Object.entries(next).map(([key, value]) => [
          key,
          [...(current[key] || []), value.latency].slice(-18),
        ]),
      ),
    );
    setLastRefresh(new Date());
  }, [checkService]);

  const loadErrors = useCallback(async () => {
    if (!token) {
      setErrors([]);
      setErrorState("missing-token");
      return;
    }
    setErrorState("loading");
    try {
      const response = await fetch(`${urls.errors}/error_log?limit=80`, {
        headers: { Authorization: `Bearer ${token}` },
      });
      const body = await response.json();
      if (!response.ok)
        throw new Error(body.error || `HTTP ${response.status}`);
      setErrors(body.errors || []);
      setErrorState("ready");
    } catch (error) {
      setErrorState(error.message);
    }
  }, [token, urls.errors]);

  useEffect(() => {
    refreshHealth();
    const timer = setInterval(refreshHealth, interval * 1000);
    return () => clearInterval(timer);
  }, [refreshHealth, interval]);
  useEffect(() => {
    if (activeView === "incidents") loadErrors();
  }, [activeView, loadErrors]);

  const saveSettings = (nextUrls, nextToken) => {
    setUrls(nextUrls);
    setToken(nextToken);
    localStorage.setItem("transit-monitor-urls", JSON.stringify(nextUrls));
    localStorage.setItem("transit-monitor-token", nextToken);
  };

  const runRequest = async () => {
    const route = testerRoutes.find(
      (item) =>
        item.service === tester.service &&
        item.method === tester.method &&
        item.path === tester.path,
    );
    const isMutation = tester.method !== "GET";
    if (
      isMutation &&
      !window.confirm("This request can change data. Continue?")
    )
      return;
    setBusy(true);
    setTesterResult(null);
    const started = performance.now();
    try {
      const response = await fetch(`${urls[tester.service]}${tester.path}`, {
        method: tester.method,
        headers: {
          ...(token ? { Authorization: `Bearer ${token}` } : {}),
          ...(tester.body ? { "Content-Type": "application/json" } : {}),
        },
        body: tester.body || undefined,
      });
      const text = await response.text();
      let body;
      try {
        body = JSON.parse(text);
      } catch {
        body = text;
      }
      setTesterResult({
        ok: response.ok,
        status: response.status,
        latency: Math.round(performance.now() - started),
        body,
        label: route?.label,
      });
    } catch (error) {
      setTesterResult({
        ok: false,
        status: 0,
        latency: Math.round(performance.now() - started),
        body: { error: error.message },
      });
    } finally {
      setBusy(false);
    }
  };

  const healthyCount = Object.values(health).filter((item) => item.ok).length;
  const configuredCount = Object.keys(serviceMeta).length;
  const avgLatency = Math.round(
    Object.values(health).reduce((sum, item) => sum + (item.latency || 0), 0) /
      Math.max(Object.keys(health).length, 1),
  );

  return (
    <div className="app-shell">
      <header className="topbar">
        <div className="brand">
          <span className="brand-mark">X</span>
          <div>
            <strong>TRANSIT CONTROL ROOM</strong>
            <span>service observability</span>
          </div>
        </div>
        <div className="top-actions">
          <span className="live-dot" /> Live polling{" "}
          <select
            value={interval}
            onChange={(event) => setIntervalValue(Number(event.target.value))}
          >
            <option value="15">15 sec</option>
            <option value="30">30 sec</option>
            <option value="60">1 min</option>
          </select>
          <button className="ghost-button" onClick={refreshHealth}>
            Refresh now
          </button>
        </div>
      </header>
      <main>
        <section className="hero-row">
          <div>
            <p className="eyebrow">
              SYSTEM PULSE /{" "}
              {lastRefresh ? lastRefresh.toLocaleTimeString() : "CONNECTING"}
            </p>
            <h1>Know what is moving.</h1>
            <p className="hero-copy">
              A live field view across the APIs that keep XTransit running.
            </p>
          </div>
          <div className="pulse-stat">
            <span>Healthy services</span>
            <strong>
              {healthyCount}
              <small>/{configuredCount}</small>
            </strong>
            <em>{avgLatency} ms avg response</em>
          </div>
        </section>
        <nav className="tabs">
          <button
            className={activeView === "overview" ? "active" : ""}
            onClick={() => setActiveView("overview")}
          >
            Overview
          </button>
          <button
            className={activeView === "catalog" ? "active" : ""}
            onClick={() => setActiveView("catalog")}
          >
            Service catalog
          </button>
          <button
            className={activeView === "docs" ? "active" : ""}
            onClick={() => setActiveView("docs")}
          >
            Docs
          </button>
          <button
            className={activeView === "incidents" ? "active" : ""}
            onClick={() => setActiveView("incidents")}
          >
            Errors & bad requests <b>{errors.length || ""}</b>
          </button>
          <button
            className={activeView === "tester" ? "active" : ""}
            onClick={() => setActiveView("tester")}
          >
            Request lab
          </button>
          <button
            className={activeView === "settings" ? "active" : ""}
            onClick={() => setActiveView("settings")}
          >
            Connections
          </button>
        </nav>
        {activeView === "overview" && (
          <>
            <section className="service-grid">
              {Object.entries(serviceMeta).map(([key, meta]) => (
                <ServiceCard
                  key={key}
                  serviceKey={key}
                  meta={meta}
                  health={health[key]}
                  history={history[key] || []}
                />
              ))}
            </section>
            <section className="lower-grid">
              <div className="panel">
                <div className="panel-heading">
                  <div>
                    <p className="eyebrow">DATA MAP</p>
                    <h2>What each service serves</h2>
                  </div>
                  <span className="panel-count">
                    {configuredCount} surfaces
                  </span>
                </div>
                <div className="data-list">
                  {Object.entries(serviceMeta).map(([key, meta]) => (
                    <div className="data-row" key={key}>
                      <span className={`service-dot ${meta.color}`} />
                      <strong>{meta.label}</strong>
                      <span>{meta.data}</span>
                    </div>
                  ))}
                </div>
              </div>
              <QuickNotes />
            </section>
          </>
        )}
        {activeView === "catalog" && <Catalog />}
        {activeView === "docs" && <Docs />}
        {activeView === "incidents" && (
          <Incidents errors={errors} state={errorState} reload={loadErrors} />
        )}
        {activeView === "tester" && (
          <RequestLab
            tester={tester}
            setTester={setTester}
            result={testerResult}
            run={runRequest}
            busy={busy}
            token={token}
          />
        )}
        {activeView === "settings" && (
          <Connections
            urls={urls}
            token={token}
            user={user}
            login={login}
            logout={logout}
            save={saveSettings}
            loginLoading={loginLoading}
          />
        )}
      </main>
    </div>
  );
}

function ServiceCard({ serviceKey, meta, health, history }) {
  const status = !health
    ? "checking"
    : health.ok
      ? "healthy"
      : health.status === 0
        ? "offline"
        : "degraded";
  return (
    <article className={`service-card ${meta.color}`}>
      <div className="card-top">
        <div>
          <span className={`service-icon ${meta.color}`}>
            {meta.label.slice(0, 2).toUpperCase()}
          </span>
          <h3>{meta.label}</h3>
          <p>{meta.role}</p>
        </div>
        <span className={`status-pill ${status}`}>
          <i />
          {status}
        </span>
      </div>
      <div className="metric-line">
        <span>Response time</span>
        <strong>{health ? `${health.latency} ms` : "--"}</strong>
      </div>
      <div className="sparkline">
        {history.length > 1 ? (
          history.map((value, index) => (
            <span
              key={`${value}-${index}`}
              style={{ height: `${Math.max(10, Math.min(100, value / 4))}%` }}
            />
          ))
        ) : (
          <em>Waiting for first reading</em>
        )}
      </div>
      {health?.body && (
        <details>
          <summary>Health payload</summary>
          <pre>{pretty(health.body)}</pre>
        </details>
      )}
    </article>
  );
}

function QuickNotes() {
  return (
    <div className="panel suggestion-panel">
      <p className="eyebrow">OPERATOR NOTES</p>
      <h2>Useful next signals</h2>
      <ul>
        <li>
          <strong>Database reachability</strong>
          <span>
            Transit health already reports DB status. Employee health currently
            only proves the process is reachable.
          </span>
        </li>
        <li>
          <strong>Auth-aware checks</strong>
          <span>
            Login with admin credentials to unlock /me and error history.
          </span>
        </li>
        <li>
          <strong>Safer testing</strong>
          <span>
            The request lab is intentionally allowlisted, with confirmation
            before writes.
          </span>
        </li>
      </ul>
    </div>
  );
}
function Docs() {
  return (
    <section className="panel docs-panel">
      <div className="panel-heading">
        <div>
          <p className="eyebrow">SERVICE DOCUMENTATION</p>
          <h2>API Documentation & References</h2>
        </div>
        <span className="panel-count">
          {Object.keys(serviceMeta).length} services
        </span>
      </div>
      <div className="docs-grid">
        {Object.entries(serviceMeta).map(([key, meta]) => (
          <div className={`doc-card ${meta.color}`} key={key}>
            <div className="doc-header">
              <span className={`service-dot ${meta.color}`} />
              <div>
                <strong>{meta.label}</strong>
                <p>{meta.role}</p>
              </div>
            </div>
            <p className="doc-description">{meta.data}</p>
            <div className="doc-links">
              {meta.docs && (
                <a
                  href={meta.docs}
                  target="_blank"
                  rel="noopener noreferrer"
                  className="doc-link"
                >
                  View Documentation →
                </a>
              )}
              <details className="routes-detail">
                <summary>API Routes</summary>
                <ul>
                  {meta.routes.map((route) => (
                    <li key={route}><code>{route}</code></li>
                  ))}
                </ul>
              </details>
            </div>
          </div>
        ))}
      </div>
    </section>
  );
}
function Catalog() {
  return (
    <section className="panel catalog-panel">
      <div className="panel-heading">
        <div>
          <p className="eyebrow">ENDPOINT ATLAS</p>
          <h2>Known API surfaces</h2>
        </div>
        <span className="panel-count">read-only reference</span>
      </div>
      {Object.entries(serviceMeta).map(([key, meta]) => (
        <div className="catalog-block" key={key}>
          <div>
            <span className={`service-dot ${meta.color}`} />
            <strong>{meta.label}</strong>
            <p>{meta.data}</p>
          </div>
          <div className="route-chips">
            {meta.routes.map((route) => (
              <code key={route}>{route}</code>
            ))}
          </div>
        </div>
      ))}
    </section>
  );
}
function Incidents({ errors, state, reload }) {
  return (
    <section className="panel incidents-panel">
      <div className="panel-heading">
        <div>
          <p className="eyebrow">CENTRAL ERROR LOG</p>
          <h2>Errors & bad requests</h2>
        </div>
        <button className="ghost-button" onClick={reload}>
          Reload log
        </button>
      </div>
      {state === "missing-token" && (
        <Empty
          title="Admin token required"
          text="Add a JWT in Connections to read the protected error log."
        />
      )}
      {state !== "missing-token" && state !== "ready" && state !== "idle" && (
        <Empty title="Could not load error log" text={state} />
      )}
      {state === "ready" && !errors.length && (
        <Empty
          title="No incidents returned"
          text="The error log is clear for the selected window."
        />
      )}
      {errors.length > 0 && (
        <div className="incident-table">
          <div className="table-head">
            <span>Time</span>
            <span>Service / route</span>
            <span>Error</span>
          </div>
          {errors.map((item) => (
            <div className="table-row" key={item.id}>
              <time>{new Date(item.date).toLocaleString()}</time>
              <strong>
                {item.service}
                <small>{item.partofservice || "unspecified route"}</small>
              </strong>
              <span>{item.error}</span>
            </div>
          ))}
        </div>
      )}
    </section>
  );
}
function Empty({ title, text }) {
  return (
    <div className="empty">
      <strong>{title}</strong>
      <span>{text}</span>
    </div>
  );
}
function RequestLab({ tester, setTester, result, run, busy, token }) {
  const matching = testerRoutes.filter(
    (route) => route.service === tester.service,
  );
  return (
    <section className="lab-grid">
      <div className="panel request-panel">
        <div className="panel-heading">
          <div>
            <p className="eyebrow">CONTROLLED EXECUTION</p>
            <h2>Live request lab</h2>
          </div>
          <span className="panel-count">
            {token ? "token attached" : "anonymous"}
          </span>
        </div>
        <label>
          Service
          <select
            value={tester.service}
            onChange={(event) => {
              const route = testerRoutes.find(
                (item) => item.service === event.target.value,
              );
              setTester({
                ...tester,
                service: event.target.value,
                method: route.method,
                path: route.path,
              });
            }}
          >
            {Object.entries(serviceMeta)
              .filter(([key]) => key !== "admin")
              .map(([key, meta]) => (
                <option key={key} value={key}>
                  {meta.label}
                </option>
              ))}
          </select>
        </label>
        <label>
          Endpoint
          <select
            value={`${tester.method} ${tester.path}`}
            onChange={(event) => {
              const route = matching.find(
                (item) => `${item.method} ${item.path}` === event.target.value,
              );
              setTester({ ...tester, method: route.method, path: route.path });
            }}
          >
            {matching.map((route) => (
              <option key={`${route.method} ${route.path}`}>
                {route.method} {route.path}
              </option>
            ))}
          </select>
        </label>
        <label>
          JSON body{" "}
          <textarea
            placeholder="Optional request body"
            value={tester.body}
            onChange={(event) =>
              setTester({ ...tester, body: event.target.value })
            }
          />
        </label>
        <button className="run-button" onClick={run} disabled={busy}>
          {busy ? "Running..." : "Run request"}
        </button>
        <p className="helper">
          Requests go directly from this browser to the configured service.
          Write routes require a confirmation.
        </p>
      </div>
      <div className="panel result-panel">
        <div className="panel-heading">
          <div>
            <p className="eyebrow">RESPONSE</p>
            <h2>
              {result
                ? `${result.status || "Network"} · ${result.latency} ms`
                : "Awaiting a request"}
            </h2>
          </div>
          {result && (
            <span
              className={`status-pill ${result.ok ? "healthy" : "degraded"}`}
            >
              <i />
              {result.ok ? "success" : "failed"}
            </span>
          )}
        </div>
        {result ? (
          <pre className="response-code">{pretty(result.body)}</pre>
        ) : (
          <div className="result-placeholder">
            Pick a known route and execute it to inspect the live response.
          </div>
        )}
      </div>
    </section>
  );
}
function Connections({ urls, token, user, login, logout, save, loginLoading }) {
  const [draft, setDraft] = useState(urls);
  const [userCode, setUserCode] = useState("");
  const [password, setPassword] = useState("");
  const [loginError, setLoginError] = useState("");

  const handleLogin = (e) => {
    e.preventDefault();
    setLoginError("");
    login(userCode, password);
  };

  if (!token) {
    return (
      <section className="panel settings-panel">
        <div className="panel-heading">
          <div>
            <p className="eyebrow">RUNTIME CONFIGURATION</p>
            <h2>Connections & Login</h2>
          </div>
          <span className="panel-count">stored locally</span>
        </div>
        <p className="settings-intro">
          Point the dashboard at local Docker ports or deployed domains. Nothing
          here is sent anywhere except the service you choose to call.
        </p>
        <div className="connection-grid">
          {Object.entries(serviceMeta).map(([key, meta]) => (
            <label key={key}>
              {meta.label}
              <input
                value={draft[key]}
                onChange={(event) =>
                  setDraft({ ...draft, [key]: event.target.value })
                }
              />
            </label>
          ))}
        </div>
        <div className="login-form">
          <h3>Admin Login</h3>
          <form onSubmit={handleLogin}>
            <label>
              User Code
              <input
                type="number"
                value={userCode}
                onChange={(e) => setUserCode(e.target.value)}
                placeholder="1234"
                required
              />
            </label>
            <label>
              Password
              <input
                type="password"
                value={password}
                onChange={(e) => setPassword(e.target.value)}
                placeholder="••••••••"
                required
              />
            </label>
            {loginError && <div className="login-error">{loginError}</div>}
            <button type="submit" className="run-button save-button" disabled={loginLoading}>
              {loginLoading ? "Logging in..." : "Login"}
            </button>
          </form>
        </div>
        <button
          className="run-button save-button"
          onClick={() => save(draft, "")}
        >
          Save connections
        </button>
      </section>
    );
  }

  return (
    <section className="panel settings-panel">
      <div className="panel-heading">
        <div>
          <p className="eyebrow">RUNTIME CONFIGURATION</p>
          <h2>Connections</h2>
        </div>
        <span className="panel-count">stored locally</span>
      </div>
      <p className="settings-intro">
        Point the dashboard at local Docker ports or deployed domains. Nothing
        here is sent anywhere except the service you choose to call.
      </p>
      <div className="connection-grid">
        {Object.entries(serviceMeta).map(([key, meta]) => (
          <label key={key}>
            {meta.label}
            <input
              value={draft[key]}
              onChange={(event) =>
                setDraft({ ...draft, [key]: event.target.value })
              }
            />
          </label>
        ))}
      </div>
      <div className="user-info">
        <h3>Logged in as</h3>
        <p><strong>User Code:</strong> {user?.userCode}</p>
        <p><strong>Role:</strong> {user?.job}</p>
        <p><strong>Admin:</strong> {user?.isAdmin ? "Yes" : "No"}</p>
        <button className="ghost-button" onClick={logout}>Logout</button>
      </div>
      <button
        className="run-button save-button"
        onClick={() => save(draft, token)}
      >
        Save connections
      </button>
    </section>
  );
}

export default App;