import { useState, useCallback, useRef } from "react";
import { SignIn, UserButton, OrganizationSwitcher, useAuth } from "@clerk/react";
import { ThemeProvider } from "./ThemeProvider";
import Sidebar from "./components/Sidebar";
import StatCard from "./components/StatCard";
import WorklistTable from "./components/WorklistTable";
import CSVImport from "./components/CSVImport";
import CSVExport from "./components/CSVExport";
import ThemeToggle from "./components/ThemeToggle";
import Toast from "./components/Toast";
import { showToast } from "./lib/toast";
import { uploadToBackend, apiRecordToLocal } from "./lib/api";
import { parseCSV, processBatch } from "./lib/coverage";

function AppInner() {
  const { getToken } = useAuth();
  const [records, setRecords] = useState([]);
  const [batchId, setBatchId] = useState(null);
  const [activeFilter, setActiveFilter] = useState("all");
  const [importLabel, setImportLabel] = useState("No data imported");
  const csvImportRef = useRef(null);

  const ooc = records.filter((r) => r.flag === "OUT_OF_COVERAGE").length;
  const visitDue = records.filter((r) => r.flag === "VISIT_DUE").length;
  const refill = records.filter((r) => r.flag === "REFILL_WINDOW").length;
  const okCount = records.filter((r) => r.flag === "OK").length;
  const urgent = ooc + visitDue;

  const handleResults = useCallback(async (file) => {
    const label = new Date().toLocaleDateString("en-US", {
      month: "short",
      day: "numeric",
      year: "numeric",
    });

    const token = await getToken().catch(() => null);
    const data = await uploadToBackend(file, token);

    if (data) {
      const results = data.records.map(apiRecordToLocal);
      setRecords(results);
      setBatchId(data.batch_id || null);
      setImportLabel(`${file.name} · ${label} · via Signal API`);
      let msg = `Loaded ${data.total} patient${data.total !== 1 ? "s" : ""} from ${file.name}`;
      if (data.skipped) msg += ` · ${data.skipped} skipped`;
      showToast(msg);
      return;
    }

    // Backend unreachable — process locally
    setBatchId(null);
    const reader = new FileReader();
    reader.onload = (e) => {
      const rows = parseCSV(e.target.result);
      const { results, skipped } = processBatch(rows);
      setRecords(results);
      setImportLabel(`${file.name} · ${label} · local processing`);
      let msg = `Loaded ${results.length} patient${results.length !== 1 ? "s" : ""} from ${file.name}`;
      if (skipped.length) msg += ` · ${skipped.length} skipped`;
      showToast(msg);
    };
    reader.readAsText(file);
  }, [getToken]);

  return (
    <div className="flex w-full min-h-screen bg-[var(--bg-page)] text-[var(--text-primary)] transition-colors">
      {/* Sidebar */}
      <Sidebar
        oocCount={ooc}
        visitDueCount={visitDue}
        refillCount={refill}
        activeFilter={activeFilter}
        onFilterChange={setActiveFilter}
        onImportClick={() => csvImportRef.current?.trigger()}
      />

      {/* Hidden CSV import trigger */}
      <CSVImport
        ref={csvImportRef}
        onResults={handleResults}
      />

      {/* Main */}
      <main className="ml-[240px] flex-1 flex flex-col">
        {/* Topbar */}
        <header className="bg-[var(--bg-card)] border-b border-[var(--border-color)] px-7 h-[60px] flex items-center justify-between sticky top-0 z-10 transition-colors">
          <div className="flex items-center gap-4">
            <h1 className="font-heading font-bold text-lg text-[var(--text-heading)]">
              Outreach Worklist
            </h1>
            <span className="font-mono text-[11px] text-[var(--text-muted)] px-2 py-[3px] bg-[var(--bg-elevated)] rounded">
              {importLabel}
            </span>
          </div>
          <div className="flex items-center gap-[10px]">
            <ThemeToggle />
            <CSVExport records={records} batchId={batchId} />
            <OrganizationSwitcher hidePersonal />
            <UserButton />
          </div>
        </header>

        {/* Content */}
        <div className="p-7">
          {/* Stats row */}
          <div className="grid grid-cols-3 gap-4 mb-6">
            <StatCard
              priority
              label="⚡ Prescriber Action"
              value={urgent}
              sub={`${ooc} out of coverage · ${visitDue} visit${visitDue !== 1 ? "s" : ""} due — prescriber contact required`}
            />
            <StatCard
              label="⚠ Resupply Ready"
              value={refill}
              sub="patients within resupply window — initiate now"
            />
            <StatCard
              label="✓ Active"
              value={okCount}
              sub="patients with supply on track — no action needed"
            />
          </div>

          {/* Worklist */}
          <WorklistTable
            records={records}
            activeFilter={activeFilter}
            onFilterChange={setActiveFilter}
          />
        </div>
      </main>

      <Toast />
    </div>
  );
}

export default function App() {
  const { isSignedIn, isLoaded } = useAuth();

  if (!isLoaded) {
    return <div className="flex items-center justify-center min-h-screen bg-[#F0EAE1]" />;
  }

  if (!isSignedIn) {
    return (
      <div className="flex items-center justify-center min-h-screen bg-[#F0EAE1]">
        <SignIn routing="hash" />
      </div>
    );
  }

  return (
    <ThemeProvider>
      <AppInner />
    </ThemeProvider>
  );
}