// ToolShim — recovers structured tool calls from plain-text model output.
// When the model emits tool calls as plain text instead of structured JSON,
// this shim attempts to parse and recover them.

export interface ParsedToolCall {
  id: string;
  name: string;
  arguments: string;
}

const TOOL_CALL_PATTERN = /<tool_call>\s*<name>(.+?)<\/name>\s*<arguments>(.+?)<\/arguments>\s*<\/tool_call>/gs;
const JSON_TOOL_PATTERN = /\{\s*"name":\s*"([^"]+)",\s*"arguments":\s*({.+?})\s*\}/gs;

export function extractToolCalls(text: string): ParsedToolCall[] {
  const calls: ParsedToolCall[] = [];
  let match: RegExpExecArray | null;

  // Try XML-style tool calls (common in Qwen output)
  const xmlRegex = new RegExp(TOOL_CALL_PATTERN);
  while ((match = xmlRegex.exec(text)) !== null) {
    calls.push({
      id: `call_${calls.length}`,
      name: match[1]!.trim(),
      arguments: match[2]!.trim(),
    });
  }

  if (calls.length > 0) return calls;

  // Try JSON-style tool calls
  const jsonRegex = new RegExp(JSON_TOOL_PATTERN);
  while ((match = jsonRegex.exec(text)) !== null) {
    calls.push({
      id: `call_${calls.length}`,
      name: match[1]!.trim(),
      arguments: match[2]!.trim(),
    });
  }

  return calls;
}

export function hasToolCallMarkup(text: string): boolean {
  return TOOL_CALL_PATTERN.test(text) || JSON_TOOL_PATTERN.test(text);
}