import type { AgentChatMessage } from "../types";
import type { AnswerUiPart } from "./contract";

/** Short notes and map confirmations stay inline; dense data and reports can expand. */
export function canExpandAnswer(parts: AnswerUiPart[]): boolean {
  let textLength = 0;
  for (const part of parts) {
    if (part.type === "text") {
      textLength += part.text.replace(/\[\[ui:[^\]\r\n]*\]\]/g, "").length;
    } else {
      for (const node of Object.values(part.block.spec.elements)) {
        if (["Table", "Chart", "FollowUpForm"].includes(node.type)) return true;
        if (node.type === "Text" && typeof node.props.text === "string") textLength += node.props.text.length;
        if (node.type === "Evidence" && typeof node.props.summary === "string") textLength += node.props.summary.length;
        if (node.type === "Result" && typeof node.props.summary === "string") textLength += node.props.summary.length;
      }
    }
  }
  return textLength >= 1200;
}

/** Readable copy/TTS text for the same ordered parts shown in the answer. */
export function getAnswerPartsTranscript(parts: AnswerUiPart[]): string {
  return parts.reduce((text, part) => {
    const next = part.type === "text" ? part.text : part.block.fallback_text;
    if (!text || !next) return text + next;
    return text + (text.endsWith("\n") || next.startsWith("\n") ? "" : "\n\n") + next;
  }, "");
}

/** Final report transcript excludes process blocks and resolves authorized anchors. */
export function getFinalAnswerTranscript(message: AgentChatMessage): string {
  return getAnswerPartsTranscript(getAnswerPresentation(message).report);
}

function splitAnchors(content: string): Array<{ text: string } | { id: string }> {
  const result: Array<{ text: string } | { id: string }> = [];
  let buffer = "";
  let fence: { character: string; length: number } | undefined;
  for (const line of content.match(/[^\n]*\n|[^\n]+$/g) ?? []) {
    const bare = line.replace(/\r?\n$/, "");
    const delimiter = /^ {0,3}(`{3,}|~{3,})(.*)$/.exec(bare);
    if (fence) {
      buffer += line;
      if (delimiter && delimiter[1][0] === fence.character && delimiter[1].length >= fence.length && !delimiter[2].trim()) fence = undefined;
      continue;
    }
    if (delimiter) {
      fence = { character: delimiter[1][0], length: delimiter[1].length };
      buffer += line;
      continue;
    }
    const anchor = /^ {0,3}\[\[ui:([^\]\r\n]*)\]\][ \t]*$/.exec(bare);
    if (!anchor) { buffer += line; continue; }
    if (buffer.trim()) result.push({ text: buffer });
    buffer = "";
    result.push({ id: anchor[1] });
  }
  if (buffer.trim()) result.push({ text: buffer });
  return result;
}

export function getAnswerPresentation(message: AgentChatMessage): {
  report: AnswerUiPart[];
  process: AnswerUiPart[];
  final: boolean;
} {
  const parts = message.answerParts ??
    (message.content ? [{ type: "text" as const, text: message.content }] : []);
  if (!message.finalAnswer) {
    const isProcess = (part: AnswerUiPart) => part.type === "answer-ui" && part.block.phase === "process";
    return { report: parts.filter((part) => !isProcess(part)), process: parts.filter(isProcess), final: false };
  }
  const selected = new Set(message.finalAnswer.uiBlockIds);
  const available = new Map(parts.flatMap((part) =>
    part.type === "answer-ui" ? [[part.block.block_id, part] as const] : []));
  const mounted = new Set<string>();
  const anchored = new Set<string>();
  const report: AnswerUiPart[] = [];
  for (const segment of splitAnchors(message.finalAnswer.content)) {
    if ("text" in segment) { report.push({ type: "text", text: segment.text }); continue; }
    anchored.add(segment.id);
    const part = available.get(segment.id);
    if (!selected.has(segment.id) || !part || part.block.phase === "process") {
      report.push({ type: "text", text: "交互内容暂不可用。\n" });
    } else if (!mounted.has(segment.id)) {
      mounted.add(segment.id);
      report.push(part);
    }
  }
  // Old reports carried references without positional anchors.
  for (const id of selected) {
    const part = available.get(id);
    if (part && part.block.phase !== "process" && !mounted.has(id) && !anchored.has(id)) {
      mounted.add(id);
      report.push(part);
    }
  }
  const process = parts.filter((part) => part.type === "answer-ui"
    ? !mounted.has(part.block.block_id)
    : part.text.trim() !== message.finalAnswer!.content.trim());
  return { report, process, final: true };
}