frontend/src/App.tsx

import { useState, useEffect, Fragment } from "react";
import type { CorpusStats } from "./types";
import { api, checkConnection } from "./api";
import TrainingPanel from "./components/TrainingPanel";
import EngineSetup from "./components/EngineSetup";
import SemanticSearch from "./components/SemanticSearch";
import TextCompare from "./components/TextCompare";
import SimilarWords from "./components/SimilarWords";
import ContextAnalysis from "./components/ContextAnalysis";
import AnomalyPanel from "./components/AnomalyPanel";
import Word2VecPanel from "./components/Word2VecPanel";
import DatasetPanel from "./components/DatasetPanel";
import MetricCard from "./components/MetricCard";
import "./styles.css";

type NavGroup = "data" | "training";
type TrainingTab = "model" | "w2v";
type AnalysisTab = "context" | "anomalies";

const STEPS: { id: NavGroup; label: string }[] = [
  { id: "data", label: "Data & Setup" },
  { id: "training", label: "Training" },
];

const TRAINING_TABS: { id: TrainingTab; label: string }[] = [
  { id: "model", label: "Fine-tune Model" },
  { id: "w2v", label: "Word2Vec Baseline" },
];

const ANALYSIS_TABS: { id: AnalysisTab; label: string }[] = [
  { id: "context", label: "Context" },
  { id: "anomalies", label: "Anomalies" },
];

export default function App() {
  const [group, setGroup] = useState<NavGroup>("data");
  const [trainingTab, setTrainingTab] = useState<TrainingTab>("w2v");
  const [analysisTab, setAnalysisTab] = useState<AnalysisTab>("context");
  const [stats, setStats] = useState<CorpusStats | null>(null);
  const [showManualSetup, setShowManualSetup] = useState(false);
  const [serverError, setServerError] = useState<string | null>(null);
  const [w2vReady, setW2vReady] = useState(false);
  const [w2vInfo, setW2vInfo] = useState<{ vocab_size: number; sentences: number; vector_size: number } | null>(null);

  useEffect(() => {
    checkConnection().then((err) => {
      setServerError(err);
      if (!err) {
        api.getStats().then(setStats).catch(() => {});
        api.w2vStatus().then(res => {
          if (res.ready) {
            setW2vReady(true);
            setW2vInfo({ vocab_size: res.vocab_size!, sentences: res.sentences!, vector_size: res.vector_size! });
            setGroup("training");
          }
        }).catch(() => {});
      }
    });
    const interval = setInterval(() => {
      checkConnection().then(setServerError);
    }, 15000);
    return () => clearInterval(interval);
  }, []);

  function handleW2vReady(ready: boolean, info?: { vocab_size: number; sentences: number; vector_size: number }) {
    setW2vReady(ready);
    setW2vInfo(ready && info ? info : null);
  }

  return (
    <div className="app">
      <header className="app-header">
        <h1>Contextual Similarity Engine</h1>
        {stats && (
          <div className="header-stats">
            <span className="badge">{stats.model_name}</span>
            <span className="badge">{stats.total_documents} docs</span>
            <span className="badge">{stats.total_chunks} chunks</span>
          </div>
        )}
      </header>

      {serverError && (
        <div className="server-error-banner">
          <strong>Server unavailable:</strong> {serverError}
        </div>
      )}

      {/* Progress Stepper — hidden once training is complete */}
      {!w2vReady && (
      <nav className="stepper">
        {STEPS.map((step, i) => {
          const active = group === step.id;
          const done = (step.id === "data" && stats !== null && stats.index_built)
            || (step.id === "training" && w2vReady);
          return (
            <Fragment key={step.id}>
              {i > 0 && <div className="stepper-line stepper-line-active" />}
              <div className="stepper-item">
                <button
                  className={`stepper-circle ${active ? "stepper-active" : ""} ${done && !active ? "stepper-done" : ""}`}
                  onClick={() => setGroup(step.id)}
                >
                  {done && !active ? "✓" : i + 1}
                </button>
                <span className={`stepper-label ${active ? "stepper-label-active" : ""}`}>
                  {step.label}
                </span>
              </div>
            </Fragment>
          );
        })}
      </nav>
      )}

      {/* Content */}
      <main className="content">
        {group === "data" && (
          <>
            <DatasetPanel onStatsUpdate={setStats} onLoaded={() => setGroup("training")} />
            <button
              className="collapsible-toggle"
              onClick={() => setShowManualSetup(!showManualSetup)}
            >
              <span className="collapsible-arrow">{showManualSetup ? "▾" : "▸"}</span>
              Or add documents manually
            </button>
            {showManualSetup && <EngineSetup onStatsUpdate={setStats} />}
          </>
        )}

        {group === "training" && !w2vReady && (
          <>
            <nav className="subtabs">
              {TRAINING_TABS.map((t) => (
                <button
                  key={t.id}
                  className={`subtab ${trainingTab === t.id ? "subtab-active" : ""}`}
                  onClick={() => setTrainingTab(t.id)}
                >
                  {t.label}
                </button>
              ))}
            </nav>
            {trainingTab === "model" && <TrainingPanel />}
            {trainingTab === "w2v" && <Word2VecPanel onReady={handleW2vReady} />}
          </>
        )}

        {group === "training" && w2vReady && w2vInfo && (
          <>
            <div className="panel">
              <h2 style={{ marginTop: 0 }}>Trained Corpus</h2>
              <p className="panel-desc">
                Word2Vec model is trained and persisted. Use the tools below to explore similarity.
              </p>
              <div className="metric-grid">
                <MetricCard value={w2vInfo.vocab_size} label="Vocabulary" />
                <MetricCard value={w2vInfo.sentences} label="Sentences" />
                <MetricCard value={w2vInfo.vector_size} label="Dimensions" />
              </div>
            </div>

            <nav className="subtabs">
              {ANALYSIS_TABS.map((t) => (
                <button
                  key={t.id}
                  className={`subtab ${analysisTab === t.id ? "subtab-active" : ""}`}
                  onClick={() => setAnalysisTab(t.id)}
                >
                  {t.label}
                </button>
              ))}
            </nav>

            {analysisTab === "context" && (
              <>
                <SimilarWords />
                <TextCompare />
                <SemanticSearch />
                <ContextAnalysis />
              </>
            )}
            {analysisTab === "anomalies" && <AnomalyPanel />}
          </>
        )}
      </main>
    </div>
  );
}