import { useEffect, useMemo, useState } from "react";
import { Link, useSearchParams } from "react-router-dom";
import { api } from "../api/client";
import type { Dashboard as DashboardData, IntegrationStatus, KnowledgeHealth } from "../api/types";
import { useAuth } from "../context/AuthContext";
import { useDemoGuide } from "../context/DemoGuideContext";
import { useDemoManifest } from "../context/DemoManifestContext";
import { SeverityBadge, StatusBadge } from "../components/Badge";
import { Icon } from "../components/Icons";
import { ErrorState, IntegrationMark, LoadingState, PageHeader, SectionHeading } from "../components/PageChrome";
import { N8N_STATE_META, MCP_STATE_META } from "../data/integrationLabels";

const FLEET_METRICS: Array<{ key: keyof DashboardData["metrics"]; label: string; tone: string }> = [
  { key: "available", label: "Available", tone: "ready" },
  { key: "rented", label: "Rented", tone: "neutral" },
  { key: "cleaning", label: "Cleaning", tone: "neutral" },
  { key: "maintenance", label: "Maintenance", tone: "warning" },
  { key: "blocked", label: "Blocked", tone: "critical" },
];

function localTime(value: string, withDate = false) {
  return new Date(value).toLocaleString("en-GB", {
    ...(withDate ? { day: "2-digit", month: "short" } : {}),
    hour: "2-digit",
    minute: "2-digit",
    timeZone: "Europe/Brussels",
  });
}

export function Dashboard() {
  const { user } = useAuth();
  const { manifest } = useDemoManifest();
  const { openGuide, restart, currentIndex, completed, totalSteps } = useDemoGuide();
  const [searchParams, setSearchParams] = useSearchParams();
  const canSeeQuality = user?.role === "operations_manager";
  const canSeeAutomation = user?.role === "operations_manager";

  useEffect(() => {
    if (searchParams.get("guide") === "start") {
      restart();
      openGuide();
      setSearchParams({}, { replace: true });
    }
    // Only ever react to the initial `?guide=start` marker set by the login screen's
    // "Start begeleide demo" CTA, so this intentionally runs once on mount.
  }, []);
  const [data, setData] = useState<DashboardData | null>(null);
  const [knowledge, setKnowledge] = useState<KnowledgeHealth | null>(null);
  const [integrationStatus, setIntegrationStatus] = useState<IntegrationStatus | null>(null);
  const [error, setError] = useState<string | null>(null);
  const [severity, setSeverity] = useState("all");
  const [query, setQuery] = useState("");

  useEffect(() => {
    api.get<DashboardData>("/api/v1/dashboard").then(setData).catch(() => setError("Dashboard data is unavailable right now."));
    api.get<KnowledgeHealth>("/api/v1/knowledge/status").then(setKnowledge).catch(() => setKnowledge(null));
  }, []);

  useEffect(() => {
    if (!canSeeAutomation) return;
    api
      .get<IntegrationStatus>("/api/v1/integrations/status")
      .then(setIntegrationStatus)
      .catch(() => setIntegrationStatus(null));
  }, [canSeeAutomation]);

  const attention = useMemo(() => data?.attention_items.filter((item) => {
    const matchesSeverity = severity === "all" || item.severity === severity;
    const haystack = `${item.title} ${item.detail} ${item.link_ref}`.toLowerCase();
    return matchesSeverity && haystack.includes(query.toLowerCase());
  }) ?? [], [data, query, severity]);

  if (error) return <ErrorState message={error} />;
  if (!data) return <LoadingState label="Loading operations overview…" />;

  const latestRun = data.recent_automation[0];
  const n8nState = !latestRun ? "No delivery yet" : latestRun.status === "failed" ? "Needs attention" : latestRun.status;

  return (
    <div className="page dashboard-page">
      <PageHeader eyebrow="Operations / Live overview" title="Good morning. Here’s the fleet." description="Readiness, exceptions and hand-offs across today’s operation." actions={<Link className="button button-secondary" to="/vehicles"><Icon name="fleet" /> View fleet</Link>} />

      <section className="demo-start-panel" aria-label="Demo starten">
        <div>
          <Icon name="spark" />
          <div>
            <strong>Probeer een demonstratiescenario</strong>
            <span>
              {manifest ? `${manifest.scenarios.filter((s) => s.ready).length} van ${manifest.scenarios.length} scenario's klaar voor demo.` : "Vijf afgebakende scenario's."}
            </span>
          </div>
        </div>
        <div className="demo-start-actions">
          {user?.role === "operations_manager" && (
            <button type="button" className="button button-secondary" onClick={openGuide}>
              <Icon name="spark" /> {completed.size > 0 ? `Verder met demo-gids (${currentIndex + 1}/${totalSteps})` : "Start demo-gids"}
            </button>
          )}
          <Link className="button button-primary" to="/scenarios">Bekijk scenario's <Icon name="chevron" /></Link>
        </div>
      </section>

      <section className="readiness-band" aria-labelledby="readiness-heading">
        <div className="readiness-label">
          <span className="live-indicator" />
          <div><h2 id="readiness-heading">Fleet readiness</h2><p>Live from persisted vehicle state</p></div>
        </div>
        <dl className="readiness-metrics">
          {FLEET_METRICS.map((metric) => (
            <div key={metric.key} className={`metric-cell metric-${metric.tone}`}>
              <dt>{metric.label}</dt><dd>{data.metrics[metric.key]}</dd>
            </div>
          ))}
        </dl>
        <Link className="inline-action" to="/vehicles">Open fleet <Icon name="chevron" /></Link>
      </section>

      <div className="operations-grid">
        <section className="work-panel attention-panel" aria-labelledby="attention-heading">
          <SectionHeading title="Attention queue" description={`${data.metrics.open_quality_issues} open quality issues · ${data.metrics.pending_or_failed_workflows} workflow exceptions`} action={canSeeQuality ? <Link to="/data-quality">Review queue <Icon name="chevron" /></Link> : undefined} />
          <div className="queue-controls">
            <label className="compact-search"><Icon name="search" /><span className="visually-hidden">Search attention queue</span><input value={query} onChange={(event) => setQuery(event.target.value)} placeholder="Filter issues…" /></label>
            <label><span className="visually-hidden">Severity</span><select value={severity} onChange={(event) => setSeverity(event.target.value)}><option value="all">All severity</option><option value="high">Critical</option><option value="medium">Warning</option><option value="low">Info</option></select></label>
          </div>
          {attention.length === 0 ? <p className="quiet-empty"><Icon name="check" /> No issues match this filter.</p> : (
            <ul className="attention-list">
              {attention.slice(0, 6).map((item, index) => (
                <li key={`${item.link_ref}-${index}`}>
                  <SeverityBadge severity={item.severity} />
                  <div className="queue-copy">
                    <p className="attention-title">
                      {item.issue_ref && canSeeQuality ? (
                        <Link to={`/data-quality/${item.issue_ref}`}>{item.title}</Link>
                      ) : item.link_type === "vehicle" ? (
                        <Link to={`/vehicles/${item.link_ref}`}>{item.title}</Link>
                      ) : (
                        item.title
                      )}
                    </p>
                    <p className="attention-detail">{item.detail}</p>
                  </div>
                  <span className="queue-ref">{item.link_ref}</span>
                  <Icon name="chevron" className="row-chevron" />
                </li>
              ))}
            </ul>
          )}
        </section>

        <section className="work-panel timeline-panel" aria-labelledby="today-heading">
          <SectionHeading title="Today’s movements" description="Departures and returns in Europe/Brussels" action={<Link to="/bookings">All bookings <Icon name="chevron" /></Link>} />
          {data.today.length === 0 ? <p className="quiet-empty"><Icon name="clock" /> No movements scheduled today.</p> : (
            <ol className="movement-timeline">
              {data.today.slice(0, 6).map((item) => (
                <li key={`${item.kind}-${item.booking_ref}`}>
                  <time dateTime={item.scheduled_at}>{localTime(item.scheduled_at)}</time>
                  <span className={`timeline-node timeline-${item.kind}`}><Icon name={item.kind === "return" ? "arrow-left" : "chevron"} /></span>
                  <div><span className="movement-kind">{item.kind}</span><Link to={`/bookings/${item.booking_ref}`}>{item.booking_ref}</Link><small>{item.vehicle_ref}</small></div>
                </li>
              ))}
            </ol>
          )}
        </section>
      </div>

      <div className="secondary-grid">
        <section className="work-panel integration-panel" aria-labelledby="integration-heading">
          <SectionHeading title="Integration pulse" description="Current evidence from connected services" action={canSeeAutomation ? <Link to="/automation">System detail <Icon name="chevron" /></Link> : undefined} />
          <ul className="integration-list">
            <li>
              <IntegrationMark kind="n8n" />
              <div>
                <strong>n8n delivery</strong>
                <span>
                  {integrationStatus
                    ? `${integrationStatus.n8n.succeeded} succeeded · ${integrationStatus.n8n.failed} failed`
                    : latestRun
                      ? `Latest event ${latestRun.aggregate_ref}`
                      : "No workflow evidence recorded"}
                </span>
              </div>
              {(() => {
                const meta = integrationStatus ? N8N_STATE_META[integrationStatus.n8n.state] : null;
                return (
                  <StatusBadge
                    status={meta?.statusClass ?? n8nState.toLowerCase().replace(/ /g, "_")}
                    label={meta?.label}
                  />
                );
              })()}
            </li>
            <li>
              <IntegrationMark kind="rag" />
              <div>
                <strong>Knowledge assistant</strong>
                <span>{knowledge ? `${knowledge.provider === "ragcore" ? "RAGcore" : "Demo knowledge base"} · ${knowledge.document_count} procedures indexed` : "Health check unavailable"}</span>
              </div>
              <StatusBadge
                status={knowledge?.available ? "available" : "unavailable"}
                label={knowledge?.available ? (knowledge.provider === "ragcore" ? "Operational" : "Demo mode") : "Unavailable"}
              />
            </li>
            <li>
              <IntegrationMark kind="mcp" />
              <div>
                <strong>MCP Hub</strong>
                <span>{integrationStatus?.mcp_hub.registration_enabled ? "Registration enabled" : "Not yet connected"}</span>
              </div>
              {(() => {
                const meta = integrationStatus ? MCP_STATE_META[integrationStatus.mcp_hub.state] : null;
                return <StatusBadge status={meta?.statusClass ?? "not_configured"} label={meta?.label} />;
              })()}
            </li>
          </ul>
        </section>

        <section className="work-panel recent-panel" aria-labelledby="recent-heading">
          <SectionHeading title="Recent activity" description="Latest audited workflow changes" />
          {data.recent_automation.length === 0 ? <p className="quiet-empty">No automation activity recorded.</p> : (
            <ul className="recent-list">
              {data.recent_automation.slice(0, 4).map((run) => (
                <li key={run.event_id}><span className="activity-icon"><Icon name="activity" /></span><div><strong>{run.event_type.replace(/_/g, " ")}</strong><span>{run.aggregate_ref}</span></div><StatusBadge status={run.status} /><time dateTime={run.occurred_at}>{localTime(run.occurred_at, true)}</time></li>
              ))}
            </ul>
          )}
        </section>
      </div>
    </div>
  );
}