import { useQuery } from "@tanstack/react-query";
import { X } from "lucide-react";
import { getSessionDocuments } from "../api/sessions";
import type { SessionDocument, SessionSummary } from "../api/types";
import { Button } from "../components/ui/button";
import { ErrorBoundary } from "../components/ErrorBoundary";
import { SqlViewer } from "../viewers/SqlViewer";
import { SchemaLinkingViewer } from "../viewers/SchemaLinkingViewer";
import { MarkdownView } from "../viewers/MarkdownView";

interface Props {
  session: SessionSummary;
  onClose: () => void;
  onResume: (id: string) => void;
}

function statusLabel(s: SessionSummary): string {
  if (s.archived) return "Archived";
  if (s.status === "finalized") return "Completed";
  return `In progress · ${s.status}`;
}

function DocBody({ doc }: { doc: SessionDocument }) {
  if (doc.format === "sql") return <SqlViewer blocks={[{ name: doc.title, sql: doc.content }]} />;
  if (doc.format === "markdown") return <MarkdownView source={doc.content} />;
  if (doc.format === "schema-linking") {
    try {
      const linking = JSON.parse(doc.content);
      return <SchemaLinkingViewer linking={linking} />;
    } catch {
      return <pre className="whitespace-pre-wrap text-xs">{doc.content}</pre>;
    }
  }
  if (doc.format === "decisions") {
    const items = doc.content
      .split("\n")
      .filter(Boolean)
      .map((line) => {
        try { return JSON.parse(line) as { type?: string; subject?: string; detail?: string }; }
        catch { return null; }
      })
      .filter((d): d is { type?: string; subject?: string; detail?: string } => d !== null);
    if (items.length === 0) return <p className="text-sm text-muted-foreground">No decisions recorded.</p>;
    return (
      <ul className="flex flex-col divide-y divide-border/50">
        {items.map((d, i) => (
          <li key={i} className="py-3 first:pt-0">
            <span className={`inline-block rounded-md px-2 py-0.5 text-[0.62rem] font-semibold uppercase tracking-wide ${decisionChipClass(d.type ?? "")}`}>
              {(d.type ?? "decision").replace(/_/g, " ")}
            </span>
            {d.subject && <p className="mt-1.5 text-sm font-medium text-foreground">{d.subject}</p>}
            {d.detail && <p className="mt-0.5 text-sm leading-relaxed text-muted-foreground">{d.detail}</p>}
          </li>
        ))}
      </ul>
    );
  }
  return <p className="whitespace-pre-wrap text-sm leading-relaxed text-foreground/90">{doc.content}</p>;
}

/** Semantic tint for a decision-type chip: approvals/promotions read as progress
 *  (green), exclusions as neutral, everything else carries the brand accent. */
function decisionChipClass(type: string): string {
  const t = type.toLowerCase();
  if (t.includes("approved") || t.includes("promoted"))
    return "bg-[oklch(var(--success)/0.15)] text-[oklch(0.47_0.12_165)]";
  if (t.includes("excluded") || t.includes("rejected") || t.includes("reopened"))
    return "bg-muted text-muted-foreground";
  return "bg-[oklch(var(--primary)/0.1)] text-primary";
}

export function SessionDocumentsPanel({ session, onClose, onResume }: Props) {
  const { data: docs = [], isLoading } = useQuery<SessionDocument[]>({
    queryKey: ["session-documents", session.id],
    queryFn: () => getSessionDocuments(session.id),
  });
  const resumable = session.status !== "finalized" && !session.archived;

  return (
    <aside className="flex w-[30vw] max-w-[30vw] shrink-0 flex-col border-r border-border bg-sidebar">
      <div className="flex items-start justify-between gap-2 border-b border-border/60 px-3 py-3">
        <div className="min-w-0">
          <h2 className="truncate font-heading text-sm font-semibold text-foreground">
            {session.name || session.question}
          </h2>
          <p className="thot-label mt-0.5">{statusLabel(session)}</p>
        </div>
        <div className="flex shrink-0 items-center gap-1">
          {resumable && (
            <Button size="sm" variant="outline" onClick={() => onResume(session.id)}>Resume</Button>
          )}
          <Button size="icon-sm" variant="ghost" aria-label="Close panel" onClick={onClose}>
            <X className="size-4" />
          </Button>
        </div>
      </div>
      <div className="flex-1 overflow-y-auto px-3 py-5">
        {isLoading ? (
          <p className="text-xs text-muted-foreground">Loading…</p>
        ) : (
          <div className="flex max-w-[76ch] flex-col gap-7">
            {docs.map((doc, idx) => (
              <section key={doc.key} className={idx > 0 ? "border-t border-border/50 pt-7" : ""}>
                <div className="mb-3 flex items-center gap-2">
                  <h3 className="thot-label">
                    {doc.title}
                  </h3>
                  {doc.phase !== "—" && (
                    <span className="rounded-md bg-muted px-1.5 py-0.5 font-mono text-[0.6rem] font-medium text-muted-foreground">
                      {doc.phase}
                    </span>
                  )}
                </div>
                {/* Isolate each document: a viewer that crashes on malformed
                    content degrades to a fallback in place, leaving the rest of
                    the panel intact instead of blanking the whole tree. */}
                <ErrorBoundary resetKeys={[doc.key, doc.content]} label="document">
                  <DocBody doc={doc} />
                </ErrorBoundary>
              </section>
            ))}
          </div>
        )}
      </div>
    </aside>
  );
}