import type { CallToolResult, Tool } from "@modelcontextprotocol/sdk/types.js";

const READ_ONLY_PREFIXES = ["get_", "list_", "search_", "validate_", "audit_", "ping_"];
const DESTRUCTIVE_PREFIXES = ["delete_", "remove_", "restore_", "sync_"];

/** Advertise intent without changing the existing tool names or input contracts. */
export function presentToolDefinitions(tools: Tool[]): Tool[] {
  return tools.map((tool) => {
    const readOnly = READ_ONLY_PREFIXES.some((prefix) => tool.name.startsWith(prefix));
    const destructive = DESTRUCTIVE_PREFIXES.some((prefix) => tool.name.startsWith(prefix));

    return {
      ...tool,
      annotations: {
        ...tool.annotations,
        readOnlyHint: readOnly,
        ...(readOnly ? { idempotentHint: true, destructiveHint: false } : {}),
        ...(destructive ? { destructiveHint: true } : {}),
        ...(tool.name === "upload_product_image_from_url" ? { openWorldHint: true } : {}),
      },
    };
  });
}

/** Keep text responses for existing clients while exposing JSON as machine-readable data. */
export function withStructuredContent(result: CallToolResult): CallToolResult {
  if (result.structuredContent) return result;
  const textBlocks = result.content.filter((item) => item.type === "text");
  if (textBlocks.length !== 1) return result;

  try {
    const parsed: unknown = JSON.parse(textBlocks[0]!.text);
    if (parsed === null || typeof parsed !== "object") return result;
    return {
      ...result,
      structuredContent: Array.isArray(parsed) ? { data: parsed } : parsed as Record<string, unknown>,
    };
  } catch {
    return result;
  }
}