import { useCallback, useEffect, useState } from "react";
import { Link } from "react-router-dom";
import { useTranslation } from "react-i18next";
import { api, ApiError } from "../api/client";
import type { DataQualityIssue, ScanResult } from "../api/types";
import { useAuth } from "../context/AuthContext";
import { SeverityBadge, StatusBadge } from "../components/Badge";
import { EmptyState, ErrorState, LoadingState, PageHeader } from "../components/PageChrome";

const RULE_TYPES = [
  "possible_duplicate_customer",
  "missing_required_field",
  "odometer_regression",
  "booking_overlap",
  "vehicle_status_conflict",
];

export function DataQuality() {
  const { t } = useTranslation("quality");
  const { user } = useAuth();
  const [issues, setIssues] = useState<DataQualityIssue[] | null>(null);
  const [error, setError] = useState<string | null>(null);
  const [status, setStatus] = useState("open");
  const [ruleType, setRuleType] = useState("");
  const [scanning, setScanning] = useState(false);
  const [scanError, setScanError] = useState<string | null>(null);
  const [scanResult, setScanResult] = useState<ScanResult | null>(null);
  const [confirmingScan, setConfirmingScan] = useState(false);
  const [demoScenariosOnly, setDemoScenariosOnly] = useState(false);

  const load = useCallback(() => {
    if (user?.role !== "operations_manager") return;
    setIssues(null);
    setError(null);
    const params = new URLSearchParams();
    if (status) params.set("status", status);
    if (ruleType) params.set("rule_type", ruleType);
    api
      .get<DataQualityIssue[]>(`/api/v1/data-quality/issues?${params.toString()}`)
      .then(setIssues)
      .catch(() => setError(t("list.unavailable")));
  }, [status, ruleType, user]);

  useEffect(() => {
    load();
  }, [load]);

  async function handleScan() {
    setScanError(null);
    setScanning(true);
    try {
      const result = await api.post<ScanResult>("/api/v1/data-quality/scan");
      setScanResult(result);
      setConfirmingScan(false);
      load();
    } catch (err) {
      setScanError(err instanceof ApiError ? err.message : t("list.scanFailed"));
    } finally {
      setScanning(false);
    }
  }

  if (user?.role !== "operations_manager") {
    return (
      <div className="page">
        <PageHeader eyebrow={t("list.eyebrow")} title={t("list.title")} description={t("detail.managerOnlyDetail")} />
        <p>{t("detail.managerOnlyDetail")}</p>
      </div>
    );
  }

  const scanTotal = scanResult ? Object.values(scanResult.created).reduce((a, b) => a + b, 0) : 0;
  const visibleIssues = issues
    ? demoScenariosOnly
      ? issues.filter((i) => i.public_ref.startsWith("DQ-DEMO-"))
      : issues
    : [];

  return (
    <div className="page">
      <PageHeader
        eyebrow={t("list.eyebrow")}
        title={t("list.title")}
        description={t("list.description")}
        actions={
          !confirmingScan ? (
            <button className="button button-secondary" type="button" onClick={() => setConfirmingScan(true)} disabled={scanning}>
              {t("list.runScan")}
            </button>
          ) : (
            <div className="confirm-bar" role="alertdialog" aria-label={t("list.confirmScanTitle")}>
              <p>{t("list.confirmScanBody")}</p>
              <button type="button" onClick={handleScan} disabled={scanning}>
                {scanning ? t("list.scanning") : t("list.confirmScanYes")}
              </button>
              <button type="button" onClick={() => setConfirmingScan(false)} disabled={scanning}>
                {t("list.cancel")}
              </button>
            </div>
          )
        }
      />

      {scanError && <p className="error" role="alert">{scanError}</p>}
      {scanResult && (
        <p className="quiet-empty" role="status">
          {t("list.scanComplete", {
            summary: scanTotal === 0
              ? t("list.scanNoNew")
              : Object.entries(scanResult.created)
                  .map(([rule, count]) => `${count} ${t(`ruleTypes.${rule}`, { defaultValue: rule.replace(/_/g, " ") })}`)
                  .join(", "),
          })}
        </p>
      )}

      <form className="filters" aria-label={t("list.title")}>
        <label>
          {t("list.statusLabel")}
          <select value={status} onChange={(e) => setStatus(e.target.value)}>
            <option value="">{t("list.statusAll")}</option>
            <option value="open">{t("list.statusOpen")}</option>
            <option value="deferred">{t("list.statusDeferred")}</option>
            <option value="resolved">{t("list.statusResolved")}</option>
            <option value="rejected">{t("list.statusRejected")}</option>
          </select>
        </label>
        <label>
          {t("list.ruleTypeLabel")}
          <select value={ruleType} onChange={(e) => setRuleType(e.target.value)}>
            <option value="">{t("list.ruleTypeAll")}</option>
            {RULE_TYPES.map((r) => (
              <option key={r} value={r}>
                {t(`ruleTypes.${r}`)}
              </option>
            ))}
          </select>
        </label>
        <label className="checkbox-label">
          <input
            type="checkbox"
            checked={demoScenariosOnly}
            onChange={(e) => setDemoScenariosOnly(e.target.checked)}
          />
          {t("list.demoScenariosOnly")}
        </label>
      </form>

      {error && <ErrorState message={error} />}
      {!error && !issues && <LoadingState label={t("list.loading")} />}
      {issues && issues.length === 0 && <EmptyState icon="check" title={t("list.queueClear")} detail={t("list.noIssuesMatch")} />}
      {issues && issues.length > 0 && visibleIssues.length === 0 && (
        <EmptyState icon="check" title={t("list.noDemoIssuesMatch")} detail={t("list.noDemoIssuesMatchDetail")} />
      )}

      {visibleIssues.length > 0 && (
        <div className="table-shell"><div className="table-meta"><span>{t("list.count", { count: visibleIssues.length })}</span><span>{t("list.evidenceBacked")}</span></div><table className="data-table">
          <caption className="visually-hidden">{t("list.title")}</caption>
          <thead>
            <tr>
              <th scope="col">{t("list.columns.reference")}</th>
              <th scope="col">{t("list.columns.rule")}</th>
              <th scope="col">{t("list.columns.entity")}</th>
              <th scope="col">{t("list.columns.severity")}</th>
              <th scope="col">{t("list.columns.status")}</th>
            </tr>
          </thead>
          <tbody>
            {visibleIssues.map((i) => (
              <tr key={i.public_ref} className="row-clickable">
                <th scope="row" data-label={t("list.columns.reference")}>
                  {i.public_ref}
                  <Link className="row-link" to={`/data-quality/${i.public_ref}`}><span className="visually-hidden">{i.public_ref}</span></Link>
                </th>
                <td data-label={t("list.columns.rule")}>{t(`ruleTypes.${i.rule_type}`, { defaultValue: i.rule_type.replace(/_/g, " ") })}</td>
                <td data-label={t("list.columns.entity")}>{i.entity_ref}</td>
                <td data-label={t("list.columns.severity")}>
                  <SeverityBadge severity={i.severity} />
                </td>
                <td data-label={t("list.columns.status")}>
                  <StatusBadge status={i.status} label={t(`list.status${i.status.charAt(0).toUpperCase()}${i.status.slice(1)}`, { defaultValue: i.status })} />
                </td>
              </tr>
            ))}
          </tbody>
        </table></div>
      )}
    </div>
  );
}