import { Client } from "@modelcontextprotocol/sdk/client/index.js";
import { StreamableHTTPClientTransport } from "@modelcontextprotocol/sdk/client/streamableHttp.js";
import { Type, type TSchema } from "@sinclair/typebox";
import { defineTool, type ToolDefinition } from "@earendil-works/pi-coding-agent";
import type { ImageContent, TextContent } from "@earendil-works/pi-ai/compat";

type McpToolResult = {
  content: Array<
    | { type: "text"; text: string }
    | { type: "image"; data: string; mimeType: string }
    | Record<string, unknown>
  >;
  isError?: boolean;
  structuredContent?: Record<string, unknown>;
};

const endpoint = process.env.SWADS_MCP_URL || "https://ads.mincode.cn/mcp";
const maxRows = Math.max(10, Number(process.env.SWADS_MCP_MAX_ROWS) || 50);
const maxTextChars = Math.max(
  10_000,
  Number(process.env.SWADS_MCP_MAX_TEXT_CHARS) || 60_000,
);
let clientPromise: Promise<Client> | undefined;

export function boundSwadsArguments(
  name: string,
  args: Record<string, unknown>,
) {
  if (name !== "metrics_semantic_query") return args;
  const query = args.query;
  if (!query || typeof query !== "object" || Array.isArray(query)) return args;
  const requested = Number((query as Record<string, unknown>).limit);
  return {
    ...args,
    query: {
      ...query,
      limit: Number.isFinite(requested)
        ? Math.min(Math.max(1, requested), maxRows)
        : maxRows,
    },
  };
}

export function compactSwadsText(text: string) {
  try {
    const parsed = JSON.parse(text) as Record<string, unknown>;
    let originalRows: number | undefined;
    let returnedRows: number | undefined;
    for (const key of ["rows", "products", "items", "data"]) {
      const value = parsed[key];
      if (!Array.isArray(value)) continue;
      originalRows = value.length;
      parsed[key] = value.slice(0, maxRows);
      returnedRows = (parsed[key] as unknown[]).length;
      break;
    }
    if (originalRows !== undefined) {
      parsed.response_compaction = {
        original_rows: originalRows,
        returned_rows: returnedRows,
        max_rows: maxRows,
        note: "Result was bounded for model context safety. Use aggregate queries or narrower filters for additional detail.",
      };
    }
    const compact = JSON.stringify(parsed);
    return compact.length <= maxTextChars
      ? compact
      : `${compact.slice(0, maxTextChars)}\n[SWADS_RESULT_TRUNCATED_AT_${maxTextChars}_CHARS]`;
  } catch {
    return text.length <= maxTextChars
      ? text
      : `${text.slice(0, maxTextChars)}\n[SWADS_RESULT_TRUNCATED_AT_${maxTextChars}_CHARS]`;
  }
}

async function swadsClient() {
  const token = process.env.SWADS_MCP_TOKEN?.trim();
  if (!token)
    throw new Error(
      "SWADS_MCP_NOT_CONFIGURED: set SWADS_MCP_TOKEN in the server environment",
    );
  clientPromise ??= (async () => {
    const client = new Client({ name: "agent-studio-mini", version: "0.1.0" });
    const transport = new StreamableHTTPClientTransport(new URL(endpoint), {
      requestInit: { headers: { Authorization: `Bearer ${token}` } },
    });
    await client.connect(transport);
    return client;
  })().catch((error) => {
    clientPromise = undefined;
    throw error;
  });
  return clientPromise;
}

function asTool(
  name: string,
  description: string,
  parameters: TSchema,
): ToolDefinition {
  return defineTool({
    name,
    label: `SW Ads · ${name}`,
    description,
    parameters,
    execute: async (_id, args, signal) => {
      const client = await swadsClient();
      const boundedArgs = boundSwadsArguments(
        name,
        args as Record<string, unknown>,
      );
      const result = (await client.callTool(
        { name, arguments: boundedArgs },
        undefined,
        { signal },
      )) as McpToolResult;
      const content: Array<TextContent | ImageContent> = [];
      for (const item of result.content) {
        if (item.type === "text")
          content.push({ type: "text", text: compactSwadsText(String(item.text)) });
        else if (item.type === "image")
          content.push({
            type: "image",
            data: String(item.data),
            mimeType: String(item.mimeType),
          });
        else content.push({ type: "text", text: JSON.stringify(item) });
      }
      if (result.isError)
        throw new Error(
          content
            .filter((item) => item.type === "text")
            .map((item) => item.text)
            .join("\n") || "SWADS_MCP_TOOL_FAILED",
        );
      return {
        content,
        details: {
          source: "swads-mcp",
          contextBounded: true,
          maxRows,
          maxTextChars,
        },
      };
    },
  });
}

const optionalAccount = {
  external_account_id: Type.Optional(Type.Union([Type.String(), Type.Null()])),
  tenant_id: Type.Optional(Type.String()),
};

export function createSwadsReadTools(): ToolDefinition[] {
  return [
    asTool(
      "swads_whoami",
      "Read the current SW Ads identity, visible accounts, capabilities, timezone, and currency.",
      Type.Object({}, { additionalProperties: false }),
    ),
    asTool(
      "metrics_catalog",
      "Read the supported SW Ads metrics, dimensions, and semantic-query schema before querying data.",
      Type.Object({}, { additionalProperties: false }),
    ),
    asTool(
      "metrics_semantic_query",
      "Run a read-only SW Ads semantic metrics query for the current or specified account.",
      Type.Object(
        {
          ...optionalAccount,
          query: Type.Object({}, { additionalProperties: true }),
        },
        { additionalProperties: false },
      ),
    ),
    asTool(
      "commerce_list_products",
      "Read the TikTok Shop product catalog and current product metadata.",
      Type.Object(
        {
          ...optionalAccount,
          authorized_business_center_id: Type.Optional(
            Type.Union([Type.String(), Type.Null()]),
          ),
          external_shop_id: Type.Optional(Type.Union([Type.String(), Type.Null()])),
          only_selectable: Type.Optional(Type.Boolean()),
        },
        { additionalProperties: false },
      ),
    ),
  ];
}