import type { ReactElement } from "react";
import { SqlViewer, type SqlBlock } from "./SqlViewer";
import { SchemaLinkingViewer, type SchemaLinking } from "./SchemaLinkingViewer";
import { MarkdownView } from "./MarkdownView";

type ArtifactData = { kind: string; data?: unknown; content?: unknown; [k: string]: unknown };

function asRecord(v: unknown): Record<string, unknown> | null {
  return v && typeof v === "object" && !Array.isArray(v) ? (v as Record<string, unknown>) : null;
}

// The payload lives in `data` (harness contract); fall back to `content`, then the
// artifact object itself, so older/other producers still render something.
function payload(artifact: ArtifactData): unknown {
  if (artifact.data !== undefined) return artifact.data;
  if (artifact.content !== undefined) return artifact.content;
  return artifact;
}

function toSchemaLinking(raw: unknown): SchemaLinking | null {
  let obj: unknown = raw;
  if (typeof raw === "string") {
    try { obj = JSON.parse(raw); } catch { return null; }
  }
  const rec = asRecord(obj);
  if (!rec || !Array.isArray(rec.candidates)) return null;
  return {
    candidates: rec.candidates as SchemaLinking["candidates"],
    joins: Array.isArray(rec.joins) ? (rec.joins as SchemaLinking["joins"]) : [],
    excluded: Array.isArray(rec.excluded) ? (rec.excluded as SchemaLinking["excluded"]) : [],
    open_questions: Array.isArray(rec.open_questions) ? (rec.open_questions as string[]) : [],
    question: typeof rec.question === "string" ? rec.question : undefined,
  };
}

function toSqlBlocks(raw: unknown): SqlBlock[] | null {
  if (typeof raw === "string") return [{ name: "SQL", sql: raw }];
  const rec = asRecord(raw);
  if (!rec) return null;
  if (typeof rec.sql === "string") return [{ name: "SQL", sql: rec.sql }];
  if (typeof rec.content === "string") return [{ name: "SQL", sql: rec.content }];
  if (Array.isArray(rec.ctes)) {
    const blocks = rec.ctes
      .map((c) => asRecord(c))
      .filter((c): c is Record<string, unknown> => !!c && typeof c.sql === "string")
      .map((c) => ({ name: typeof c.name === "string" ? c.name : "cte", sql: c.sql as string }));
    if (typeof rec.final === "string") blocks.push({ name: "final", sql: rec.final });
    return blocks.length ? blocks : null;
  }
  return null;
}

function toMarkdown(raw: unknown): string | null {
  if (typeof raw === "string") return raw;
  const rec = asRecord(raw);
  if (!rec) return null;
  for (const k of ["markdown", "question", "text"]) {
    if (typeof rec[k] === "string") return rec[k] as string;
  }
  return null;
}

function cteNames(raw: unknown): string[] | null {
  if (Array.isArray(raw) && raw.every((x) => typeof x === "string")) return raw as string[];
  const rec = asRecord(raw);
  if (rec && Array.isArray(rec.names) && rec.names.every((x) => typeof x === "string")) {
    return rec.names as string[];
  }
  return null;
}

function JsonFallback({ value }: { value: unknown }): ReactElement {
  const text = typeof value === "string" ? value : JSON.stringify(value, null, 2);
  return (
    <pre className="overflow-auto whitespace-pre-wrap rounded bg-muted p-3 text-sm">{text}</pre>
  );
}

export function ArtifactView({ artifact }: { artifact: ArtifactData }): ReactElement {
  const kind = artifact.kind ?? "";
  const data = payload(artifact);

  if (kind === "schema_linking") {
    const linking = toSchemaLinking(data);
    if (linking) return <SchemaLinkingViewer linking={linking} />;
  }
  if (kind === "sql" || kind === "cte_result") {
    const blocks = toSqlBlocks(data);
    if (blocks) return <SqlViewer blocks={blocks} />;
  }
  if (kind === "cte_plan") {
    const names = cteNames(data);
    if (names) {
      return (
        <ol className="list-decimal pl-6 text-sm">
          {names.map((n, i) => (
            <li key={`${n}-${i}`} className="font-mono">{n}</li>
          ))}
        </ol>
      );
    }
  }
  if (kind === "question" || kind === "phase") {
    const md = toMarkdown(data);
    if (md !== null) return <MarkdownView source={md} />;
  }
  return <JsonFallback value={data} />;
}