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;
  desktopSplit?: boolean;
  hidden?: boolean;
}

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

type MemoryItem = {
  status: "approved" | "declined";
  subject: string;
  detail: string;
  rationale: string;
};

const HIDDEN_DECISION_TYPES = new Set([
  "concept_clarified",
  "memory_promoted",
  "memory_promotion_declined",
  "memory_rejected",
  "phase_approved",
  "phase_auto_approved",
  "table_approved",
  "table_promoted",
  "column_promoted",
  "cte_approved",
  "sql_approved",
  "datamart_requested",
  "datamart_declined",
]);

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 === "memories") {
    const raw = JSON.parse(doc.content) as unknown;
    const items = Array.isArray(raw)
      ? raw.filter((item): item is MemoryItem => {
          if (!item || typeof item !== "object") return false;
          const candidate = item as Partial<MemoryItem>;
          return (
            (candidate.status === "approved" || candidate.status === "declined")
            && typeof candidate.subject === "string"
            && typeof candidate.detail === "string"
            && typeof candidate.rationale === "string"
          );
        })
      : [];
    if (items.length === 0) {
      return <p className="text-sm text-muted-foreground">No memories recorded.</p>;
    }
    return (
      <ul aria-label="Memories" className="flex flex-col divide-y divide-border/50">
        {items.map((item, index) => (
          <li key={`${item.status}:${item.subject}:${index}`} className="py-4 first:pt-0">
            <span className={[
              "inline-flex rounded-md px-2 py-0.5 text-[0.62rem] font-semibold uppercase tracking-wide",
              item.status === "approved"
                ? "bg-[oklch(var(--success)/0.15)] text-[oklch(0.47_0.12_165)]"
                : "bg-muted text-muted-foreground",
            ].join(" ")}>
              {item.status === "approved" ? "Approved" : "Declined"}
            </span>
            <div className="mt-2 font-medium text-foreground">
              <MarkdownView source={item.subject} />
            </div>
            {item.detail && (
              <div className="mt-1 text-sm text-muted-foreground">
                <MarkdownView source={item.detail} />
              </div>
            )}
            {item.rationale && (
              <div className="mt-1 border-l-2 border-border pl-3 text-sm text-muted-foreground">
                <MarkdownView source={item.rationale} />
              </div>
            )}
          </li>
        ))}
      </ul>
    );
  }
  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 && !HIDDEN_DECISION_TYPES.has(d.type ?? "")
      ));
    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 && (
              <div className="mt-1.5 text-sm font-medium text-foreground">
                <MarkdownView source={d.subject} />
              </div>
            )}
            {d.detail && (
              <div className="mt-0.5 text-sm leading-relaxed text-muted-foreground">
                <MarkdownView source={d.detail} />
              </div>
            )}
          </li>
        ))}
      </ul>
    );
  }
  return <MarkdownView source={doc.content} />;
}

/** 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, desktopSplit = false, hidden = false }: 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
      aria-label="Session summary"
      aria-hidden={hidden || undefined}
      hidden={hidden}
      className={[
        "flex shrink-0 flex-col border-r border-border bg-sidebar",
        desktopSplit
          ? "w-[var(--session-panel-width)] max-w-[50%]"
          : "w-[30vw] max-w-[30vw]",
      ].join(" ")}
    >
      <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 w-full flex-col gap-7">
            {docs.map((doc, idx) => (
              <section
                key={doc.key}
                className={[
                  "w-full",
                  idx > 0 ? "border-t border-border/50 pt-7" : "",
                ].join(" ")}
              >
                <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>
  );
}