import { useEffect, useRef, useState } from "react";
import { Stack, ArrowRight, X } from "@phosphor-icons/react";
import { api, factValue, type Fact, type RunSummary } from "../lib/api";
import { Empty, Note, ProvenanceList, Spinner, StatusChip } from "./common";

const FILTERS = [
  { k: "", label: "all" },
  { k: "verified", label: "verified" },
  { k: "derived", label: "derived" },
  { k: "unverified", label: "unverified" },
  { k: "conflicted", label: "conflicted" },
  { k: "attested", label: "attested" },
  { k: "resolved", label: "resolved" },
] as const;

export function Ledger({ run, onNext }: { run: RunSummary; onNext: () => void }) {
  const [facts, setFacts] = useState<Fact[]>([]);
  const [total, setTotal] = useState(run.fact_count);
  const [streaming, setStreaming] = useState(true);
  const [filter, setFilter] = useState<string>("");
  const [open, setOpen] = useState<Fact | null>(null);
  const seen = useRef(new Set<string>());

  useEffect(() => {
    // Stream the ledger so the reviewer watches it being assembled from the filing.
    const es = new EventSource(`/api/runs/${run.id}/ledger/stream?delay_ms=14`);
    es.addEventListener("start", (e) => setTotal(JSON.parse((e as MessageEvent).data).total));
    es.addEventListener("fact", (e) => {
      const { fact } = JSON.parse((e as MessageEvent).data);
      if (seen.current.has(fact.id)) return;
      seen.current.add(fact.id);
      setFacts((prev) => [...prev, fact]);
    });
    es.addEventListener("done", () => { setStreaming(false); es.close(); });
    es.onerror = () => { setStreaming(false); es.close(); };
    return () => es.close();
  }, [run.id]);

  const shown = filter ? facts.filter((f) => f.status === filter) : facts;
  const counts = facts.reduce<Record<string, number>>((a, f) => {
    a[f.status] = (a[f.status] ?? 0) + 1;
    return a;
  }, {});

  return (
    <>
      <div className="page-head">
        <h1 className="page">Disclosure ledger</h1>
        <p className="lede">
          Each row is one atomic disclosure value read from the issuer's own filing, bound to the
          page it came from. Status is earned, never assumed: a figure is verified only when two
          independent sections agree or an accounting identity supports it. Everything else
          abstains and says what to confirm.
        </p>
      </div>

      <div className="stats" style={{ marginBottom: 14 }}>
        <div className="stat">
          <div className="stat-v">{facts.length}</div>
          <div className="stat-l">facts extracted{streaming ? " so far" : ""}</div>
        </div>
        <div className="stat">
          <div className="stat-v ok">{counts.verified ?? 0}</div>
          <div className="stat-l">verified by corroboration or identity</div>
        </div>
        <div className="stat">
          <div className="stat-v">{counts.derived ?? 0}</div>
          <div className="stat-l">derived, with lineage recorded</div>
        </div>
        <div className="stat">
          <div className="stat-v warn">{counts.unverified ?? 0}</div>
          <div className="stat-l">abstained, awaiting confirmation</div>
        </div>
        <div className="stat">
          <div className="stat-v stop">{counts.conflicted ?? 0}</div>
          <div className="stat-l">sources disagree</div>
        </div>
      </div>

      {streaming && (
        <div className="bar" style={{ marginBottom: 14 }}>
          <i style={{ width: `${total ? (facts.length / total) * 100 : 0}%` }} />
        </div>
      )}

      <section className="panel">
        <div className="panel-h">
          <Stack size={16} />
          <h2>Facts</h2>
          <span className="count">{shown.length} shown</span>
          <div className="filters" style={{ marginLeft: "auto" }}>
            {FILTERS.map((f) => (
              <button
                key={f.k}
                className="filter"
                aria-pressed={filter === f.k}
                onClick={() => setFilter(f.k)}
              >
                {f.label}
                {f.k && counts[f.k] ? ` ${counts[f.k]}` : ""}
              </button>
            ))}
          </div>
        </div>

        <div style={{ maxHeight: "58vh", overflowY: "auto" }}>
          {shown.length === 0 && !streaming ? (
            <Empty title={filter ? `No ${filter} facts` : "The ledger is empty"}>
              {filter
                ? "No figure in this filing earned that status."
                : "No disclosure value could be read from the source records."}
            </Empty>
          ) : (
            <table className="tbl">
              <thead>
                <tr>
                  <th style={{ width: "34%" }}>Disclosure</th>
                  <th className="r" style={{ width: "16%" }}>Value</th>
                  <th style={{ width: "12%" }}>Status</th>
                  <th>Source</th>
                </tr>
              </thead>
              <tbody>
                {shown.map((f, i) => (
                  <tr
                    key={f.id}
                    className={i >= shown.length - 3 && streaming ? "arrived" : ""}
                    onClick={() => setOpen(f)}
                    style={{ cursor: "pointer" }}
                  >
                    <td>
                      <div className="f-label">{f.label}</div>
                      <div className="f-id">{f.id}</div>
                      {f.note && <div className="f-note">{f.note}</div>}
                    </td>
                    <td className="r num" style={{ fontWeight: 500 }}>{factValue(f)}</td>
                    <td><StatusChip status={f.status} /></td>
                    <td>
                      <div className="f-src">{f.provenance[0]?.locator ?? "n/a"}</div>
                      {f.provenance.length > 1 && (
                        <div className="tag tag-ok" style={{ marginTop: 3, display: "inline-block" }}>
                          {f.provenance.length} sources agree
                        </div>
                      )}
                      {f.identities.length > 0 && (
                        <div className="f-id" style={{ marginTop: 3 }}>{f.identities[0]}</div>
                      )}
                    </td>
                  </tr>
                ))}
              </tbody>
            </table>
          )}
        </div>
      </section>

      <div style={{ display: "flex", gap: 10, marginTop: 16, alignItems: "center" }}>
        <button className="btn btn-primary" onClick={onNext} disabled={streaming}>
          {streaming ? <><Spinner /> Reading filing</> : <>Draft the offer document <ArrowRight size={15} /></>}
        </button>
        {!streaming && (counts.unverified ?? 0) > 0 && (
          <span style={{ fontSize: 12.5, color: "var(--text-2)" }}>
            {counts.unverified} figures abstained. The engine will list each one for attestation.
          </span>
        )}
      </div>

      {open && <FactDrawer fact={open} onClose={() => setOpen(null)} />}
    </>
  );
}

function FactDrawer({ fact, onClose }: { fact: Fact; onClose: () => void }) {
  useEffect(() => {
    const onKey = (e: KeyboardEvent) => e.key === "Escape" && onClose();
    window.addEventListener("keydown", onKey);
    return () => window.removeEventListener("keydown", onKey);
  }, [onClose]);

  return (
    <div
      style={{
        position: "fixed", inset: 0, background: "rgba(11,27,43,0.4)",
        zIndex: 50, display: "grid", placeItems: "center", padding: 20,
      }}
      onClick={onClose}
    >
      <div
        className="panel"
        style={{ maxWidth: 620, width: "100%", maxHeight: "82vh", overflowY: "auto" }}
        onClick={(e) => e.stopPropagation()}
        role="dialog"
        aria-label={fact.label}
      >
        <div className="panel-h">
          <h2>{fact.label}</h2>
          <button className="btn btn-ghost btn-sm" style={{ marginLeft: "auto" }} onClick={onClose}>
            <X size={13} /> Close
          </button>
        </div>
        <div className="panel-b" style={{ display: "grid", gap: 14 }}>
          <div style={{ display: "flex", gap: 12, alignItems: "baseline" }}>
            <span className="num" style={{ fontSize: 22, fontWeight: 600 }}>{factValue(fact)}</span>
            <StatusChip status={fact.status} />
            <span className="f-id">{fact.id}</span>
          </div>

          {fact.note && <Note tone="warn">{fact.note}</Note>}

          {fact.identities.length > 0 && (
            <div>
              <div className="f-src" style={{ marginBottom: 5 }}>Supported by</div>
              {fact.identities.map((i) => (
                <div key={i} className="mono" style={{ fontSize: 11.5, color: "var(--ok)" }}>{i}</div>
              ))}
            </div>
          )}

          {fact.derived_from.length > 0 && (
            <div>
              <div className="f-src" style={{ marginBottom: 5 }}>Derived from</div>
              {fact.derived_from.map((d) => (
                <div key={d} className="f-id">{d}</div>
              ))}
            </div>
          )}

          <div>
            <div className="f-src" style={{ marginBottom: 6 }}>
              Provenance ({fact.provenance.length})
            </div>
            <ProvenanceList provenance={fact.provenance} />
          </div>

          {fact.section_refs.length > 0 && (
            <div>
              <div className="f-src" style={{ marginBottom: 5 }}>Used in sections</div>
              <div style={{ display: "flex", gap: 5, flexWrap: "wrap" }}>
                {fact.section_refs.map((s) => (
                  <span key={s} className="tag">{s.replace(/_/g, " ")}</span>
                ))}
              </div>
            </div>
          )}
        </div>
      </div>
    </div>
  );
}