import { useEffect, useMemo, useState } from "react";
import { callSkill, fileToBrowserDocument, loadAgentConfig, loadSession, signInUrl } from "./a2a.js";

const DEFAULT_QUOTES = [
  { vendor: "Acme Bearings", quantity: 500, unit_price: 10.75, delivery_days: 12, warranty_months: 12 },
  { vendor: "Beta Industrial", quantity: 500, unit_price: 9.1, delivery_days: 8, warranty_months: 18 },
];
const DEFAULT_WEIGHTS = { price: 50, delivery: 30, warranty: 20 };

function blankQuote() {
  return { vendor: "", quantity: 1, unit_price: 0, delivery_days: 0, warranty_months: 0 };
}

function normalizeQuote(quote) {
  return {
    vendor: String(quote.vendor || "").trim(),
    quantity: Number(quote.quantity),
    unit_price: Number(quote.unit_price),
    delivery_days: Number(quote.delivery_days),
    warranty_months: Number(quote.warranty_months),
  };
}

function parsePastedQuotes(text) {
  const trimmed = text.trim();
  if (!trimmed) return [];
  try {
    const parsed = JSON.parse(trimmed);
    const rows = Array.isArray(parsed) ? parsed : parsed.quotes;
    if (Array.isArray(rows)) return rows.map(normalizeQuote);
  } catch {
    // Fall through to CSV-ish parsing.
  }
  const lines = trimmed.split(/\r?\n/).filter(Boolean);
  const hasHeader = /vendor|supplier/i.test(lines[0] || "");
  const rows = hasHeader ? lines.slice(1) : lines;
  return rows.map((line) => {
    const parts = line.split(/[,;|\t]/).map((part) => part.trim());
    return normalizeQuote({
      vendor: parts[0],
      quantity: parts[1],
      unit_price: parts[2],
      delivery_days: parts[3],
      warranty_months: parts[4],
    });
  });
}

function validateQuotes(quotes, weights) {
  const complete = quotes.map(normalizeQuote).filter((quote) => quote.vendor);
  if (complete.length < 2) return "Add at least two vendor quotes before comparing.";
  for (const quote of complete) {
    if (!Number.isFinite(quote.quantity) || quote.quantity <= 0) return `${quote.vendor}: quantity must be greater than 0.`;
    if (!Number.isFinite(quote.unit_price) || quote.unit_price < 0) return `${quote.vendor}: unit price must be 0 or greater.`;
    if (!Number.isFinite(quote.delivery_days) || quote.delivery_days < 0) return `${quote.vendor}: delivery days must be 0 or greater.`;
    if (!Number.isFinite(quote.warranty_months) || quote.warranty_months < 0) return `${quote.vendor}: warranty must be 0 or greater.`;
  }
  const totalWeight = Number(weights.price) + Number(weights.delivery) + Number(weights.warranty);
  if (!Number.isFinite(totalWeight) || totalWeight <= 0) return "Set at least one positive weight.";
  return null;
}

export function App() {
  const [config, setConfig] = useState(null);
  const [session, setSession] = useState(null);
  const [loadError, setLoadError] = useState(null);
  const [comparisonId, setComparisonId] = useState("studio-quote-v1");
  const [quotes, setQuotes] = useState(DEFAULT_QUOTES);
  const [weights, setWeights] = useState(DEFAULT_WEIGHTS);
  const [pasteText, setPasteText] = useState("");
  const [result, setResult] = useState(null);
  const [history, setHistory] = useState([]);
  const [status, setStatus] = useState("");
  const [error, setError] = useState("");
  const [running, setRunning] = useState(false);

  useEffect(() => {
    loadAgentConfig()
      .then(async (data) => {
        setConfig(data);
        try {
          setSession(await loadSession(data));
        } catch {
          setSession({ authenticated: false });
        }
      })
      .catch((err) => setLoadError(err.message || String(err)));
  }, []);

  useEffect(() => {
    try {
      const saved = JSON.parse(window.localStorage.getItem("quotejudge.history") || "[]");
      if (Array.isArray(saved)) setHistory(saved.slice(0, 8));
    } catch {
      setHistory([]);
    }
  }, []);

  const needsSignIn = Boolean(config?.auth?.invokeRequiresSession && session && !session.authenticated);
  const authHref = useMemo(() => (config ? signInUrl(config) : null), [config]);
  const validation = validateQuotes(quotes, weights);
  const totalWeight = Number(weights.price) + Number(weights.delivery) + Number(weights.warranty);

  function updateQuote(index, field, value) {
    setQuotes((current) => current.map((quote, i) => (i === index ? { ...quote, [field]: value } : quote)));
  }

  function remember(id) {
    const next = [id, ...history.filter((item) => item !== id)].slice(0, 8);
    setHistory(next);
    window.localStorage.setItem("quotejudge.history", JSON.stringify(next));
  }

  function applyPastedQuotes() {
    setError("");
    try {
      const parsed = parsePastedQuotes(pasteText);
      if (parsed.length < 2) {
        setError("Paste JSON, CSV, or pipe-separated text with at least two quotes.");
        return;
      }
      setQuotes(parsed);
      setStatus(`Loaded ${parsed.length} pasted quotes.`);
    } catch (err) {
      setError(err.message || "Could not parse pasted quotes.");
    }
  }

  async function compare(event) {
    event.preventDefault();
    if (!config) return;
    setError("");
    setStatus("");
    const message = validateQuotes(quotes, weights);
    if (message) {
      setError(message);
      return;
    }
    setRunning(true);
    try {
      const data = await callSkill(config, "compare_quotes", {
        comparison_id: comparisonId,
        quotes: quotes.map(normalizeQuote).filter((quote) => quote.vendor),
        weights: {
          price: Number(weights.price),
          delivery: Number(weights.delivery),
          warranty: Number(weights.warranty),
        },
      });
      setResult(data);
      if (data.ok) {
        remember(data.comparison_id);
        setStatus("Comparison saved. You can refresh and reopen it by ID.");
      } else {
        setError(data.message || data.code || "Comparison failed.");
      }
    } catch (err) {
      if (err.status === 401 && authHref) setError("Session expired. Sign in again to run QuoteJudge.");
      else setError(err.message || String(err));
    } finally {
      setRunning(false);
    }
  }

  async function reopen(id = comparisonId) {
    if (!config || !id) return;
    setRunning(true);
    setError("");
    setStatus("");
    try {
      const data = await callSkill(config, "get_comparison", { comparison_id: id });
      setResult(data);
      setComparisonId(id);
      if (data.ok) {
        remember(id);
        setStatus("Saved comparison reopened from managed Postgres.");
      } else {
        setError(data.message || "No saved comparison found for this ID.");
      }
    } catch (err) {
      if (err.status === 401 && authHref) setError("Session expired. Sign in again to reopen comparisons.");
      else setError(err.message || String(err));
    } finally {
      setRunning(false);
    }
  }

  async function handleFiles(event) {
    if (!config) return;
    const files = Array.from(event.target.files || []);
    if (!files.length) return;
    setRunning(true);
    setError("");
    setStatus("");
    try {
      const documents = await Promise.all(files.map((file) => fileToBrowserDocument(file)));
      const data = await callSkill(config, "compare_uploaded_quotes_browser", {
        comparison_id: comparisonId,
        documents,
        weights: {
          price: Number(weights.price),
          delivery: Number(weights.delivery),
          warranty: Number(weights.warranty),
        },
      });
      setResult(data);
      if (data.ok) {
        setQuotes(data.quotes.map(({ vendor, quantity, unit_price, delivery_days, warranty_months }) => ({ vendor, quantity, unit_price, delivery_days, warranty_months })));
        remember(data.comparison_id);
        setStatus("Uploaded quotes parsed, compared, and saved.");
      } else {
        setError(data.message || data.code || "Upload comparison failed.");
      }
    } catch (err) {
      setError(err.message || String(err));
    } finally {
      event.target.value = "";
      setRunning(false);
    }
  }

  if (!config) {
    return <main className="loading"><p>{loadError || "Loading QuoteJudge…"}</p></main>;
  }

  return (
    <main className="app-shell">
      <section className="hero card">
        <div>
          <p className="eyebrow">QuoteJudge Studio</p>
          <h1>Pick the best vendor quote with weighted, auditable scoring.</h1>
          <p className="lede">Upload or paste quotes, tune price/delivery/warranty importance, save the comparison, and reopen it after refresh. Results are calculated by typed A2A backend tools and stored per signed-in user.</p>
        </div>
        <div className="session-box">
          <span className={session?.authenticated ? "dot ok" : "dot warn"} />
          <div>
            <strong>{session?.authenticated ? "Signed in" : "Sign-in required to run"}</strong>
            <p>{session?.user?.email || session?.org?.slug || "Platform auth protects saved comparisons."}</p>
          </div>
          {needsSignIn && authHref ? <a className="button secondary" href={authHref}>Sign in</a> : null}
        </div>
      </section>

      <form className="grid" onSubmit={compare}>
        <section className="card editor">
          <div className="section-head">
            <div>
              <p className="eyebrow">Inputs</p>
              <h2>Vendor quotes</h2>
            </div>
            <button type="button" className="button ghost" onClick={() => setQuotes((rows) => [...rows, blankQuote()])}>Add quote</button>
          </div>

          <label className="field id-field">Comparison ID
            <input value={comparisonId} onChange={(e) => setComparisonId(e.target.value)} placeholder="studio-quote-v1" />
          </label>

          <div className="quote-list">
            {quotes.map((quote, index) => (
              <article className="quote-row" key={index}>
                <label>Vendor<input value={quote.vendor} onChange={(e) => updateQuote(index, "vendor", e.target.value)} /></label>
                <label>Qty<input type="number" min="1" value={quote.quantity} onChange={(e) => updateQuote(index, "quantity", e.target.value)} /></label>
                <label>Unit price<input type="number" min="0" step="0.01" value={quote.unit_price} onChange={(e) => updateQuote(index, "unit_price", e.target.value)} /></label>
                <label>Delivery days<input type="number" min="0" value={quote.delivery_days} onChange={(e) => updateQuote(index, "delivery_days", e.target.value)} /></label>
                <label>Warranty months<input type="number" min="0" value={quote.warranty_months} onChange={(e) => updateQuote(index, "warranty_months", e.target.value)} /></label>
                <button type="button" aria-label={`Remove quote ${index + 1}`} onClick={() => setQuotes((rows) => rows.filter((_, i) => i !== index))}>×</button>
              </article>
            ))}
          </div>

          <div className="paste-upload">
            <label>Paste JSON, CSV, or vendor|qty|price|delivery|warranty text
              <textarea value={pasteText} onChange={(e) => setPasteText(e.target.value)} placeholder="vendor,quantity,unit_price,delivery_days,warranty_months…" />
            </label>
            <div className="actions">
              <button type="button" className="button secondary" onClick={applyPastedQuotes}>Use pasted quotes</button>
              <label className="button secondary upload">Upload CSV/JSON/TXT
                <input type="file" multiple accept=".csv,.json,.txt,text/csv,text/plain,application/json" onChange={handleFiles} />
              </label>
            </div>
          </div>
        </section>

        <aside className="card controls">
          <p className="eyebrow">Scoring</p>
          <h2>Weights</h2>
          {Object.entries(weights).map(([key, value]) => (
            <label className="slider" key={key}>{key}<strong>{value}</strong>
              <input type="range" min="0" max="100" value={value} onChange={(e) => setWeights((w) => ({ ...w, [key]: Number(e.target.value) }))} />
            </label>
          ))}
          <p className="hint">Total weight: {totalWeight}. Scores normalize each dimension from 0 to 1, then apply these weights.</p>
          {validation ? <p className="validation">{validation}</p> : null}
          {error ? <p className="error">{error}</p> : null}
          {status ? <p className="status">{status}</p> : null}
          <button className="button primary" disabled={running || needsSignIn || Boolean(validation)} type="submit">{running ? "Running…" : "Compare & save"}</button>
          <button className="button secondary" disabled={running || needsSignIn} type="button" onClick={() => reopen()}>Reopen by ID</button>
          {needsSignIn && authHref ? <a className="signin-note" href={authHref}>Sign in with A2A Cloud to call backend tools.</a> : null}
          <div className="history">
            <h3>Recent IDs</h3>
            {history.length ? history.map((id) => <button key={id} type="button" onClick={() => reopen(id)}>{id}</button>) : <p>No saved comparisons opened in this browser yet.</p>}
          </div>
        </aside>
      </form>

      <section className="card result-card">
        <div className="section-head">
          <div>
            <p className="eyebrow">Backend result</p>
            <h2>{result?.ok ? `Recommended: ${result.recommendation.vendor}` : "No recommendation yet"}</h2>
          </div>
          {result?.ok ? <span className="score">Score {result.recommendation.score.toFixed(2)}</span> : null}
        </div>
        {result?.ok ? (
          <>
            <p className="rationale">{result.recommendation.rationale}</p>
            <div className="table-wrap">
              <table>
                <thead><tr><th>Vendor</th><th>Total</th><th>Delivery</th><th>Warranty</th><th>Weighted score</th></tr></thead>
                <tbody>
                  {result.quotes.map((quote) => (
                    <tr key={quote.vendor} className={quote.vendor === result.recommendation.vendor ? "winner" : ""}>
                      <td>{quote.vendor}</td>
                      <td>{quote.subtotal.toLocaleString(undefined, { style: "currency", currency: "BRL" })}</td>
                      <td>{quote.delivery_days} days</td>
                      <td>{quote.warranty_months} months</td>
                      <td>{quote.scores.weighted_total.toFixed(2)}</td>
                    </tr>
                  ))}
                </tbody>
              </table>
            </div>
          </>
        ) : (
          <p className="empty">Run a comparison or reopen a saved ID. Fewer than two quotes are blocked before calling the backend and also rejected by the typed tool.</p>
        )}
      </section>
    </main>
  );
}