import { MCPClient } from "@openhands/typescript-client/clients";
import type { AgentServerMCPTestRequest } from "@openhands/typescript-client";
import { getAgentServerClientOptions } from "../agent-server-client-options";
import {
  getActiveBackend,
  getRegisteredBackends,
} from "../backend-registry/active-store";
import {
  getCredentialValidationForServer,
  type CredentialValidation,
} from "#/utils/mcp-credential-validation";
import type {
  ExtendedMCPTestResponse,
  MCPOAuthStartResponse,
  MCPOAuthStatusResponse,
  MCPServerConfig,
} from "#/types/mcp-server";
import { redactMcpSecrets } from "#/utils/redact-mcp-secrets";
import { substituteRedactedMcpCredentials } from "./mcp-redacted-credentials";

const OAUTH_MCP_TEST_TIMEOUT_SECONDS = 120;

function toMcpServer(
  server: MCPServerConfig,
): AgentServerMCPTestRequest["server"] {
  if (server.type === "stdio") {
    return {
      type: "stdio",
      command: server.command!,
      ...(server.args?.length && { args: server.args }),
      ...(server.env &&
        Object.keys(server.env).length > 0 && { env: server.env }),
    };
  }
  return {
    type: server.type === "sse" ? "sse" : "http",
    url: server.url!,
    ...(server.headers &&
      Object.keys(server.headers).length > 0 && { headers: server.headers }),
    ...(server.auth ? { auth: server.auth } : {}),
  };
}

function getMcpTestTimeout(server: MCPServerConfig): number | undefined {
  if (server.auth?.strategy !== "oauth2") return server.timeout;
  return OAUTH_MCP_TEST_TIMEOUT_SECONDS;
}

async function buildMcpTestRequest(server: MCPServerConfig): Promise<{
  request: AgentServerMCPTestRequest;
  substituted: MCPServerConfig;
}> {
  const validation = getCredentialValidationForServer(server);
  const substituted = await substituteRedactedMcpCredentials(server);
  const serverSpec = toMcpServer(substituted);
  const timeout = getMcpTestTimeout(server);
  return {
    request: {
      server: serverSpec,
      ...(server.name ? { name: server.name } : {}),
      ...(timeout !== undefined ? { timeout } : {}),
      ...(validation ? { tool_call: validation.toolCall } : {}),
    },
    substituted,
  };
}

function redactMcpTestResponse(
  result: ExtendedMCPTestResponse,
  redactionSources: (MCPServerConfig | undefined)[],
): ExtendedMCPTestResponse {
  if (!result.ok) {
    return {
      ...result,
      error: redactMcpSecrets(result.error, ...redactionSources),
    };
  }
  if (result.tool_result) {
    return {
      ...result,
      tool_result: {
        ...result.tool_result,
        text: redactMcpSecrets(result.tool_result.text, ...redactionSources),
      },
    };
  }
  return result;
}

/**
 * Display-boundary post-processing shared by the test and OAuth probes:
 * scrub secrets from error/tool-result text, then let the catalog entry's
 * credential validation turn a failed read-only tool call into a
 * `credentials` failure. The interpretation only runs when the probe tool
 * is actually advertised in `tools` — a server variant that doesn't expose
 * the tool (e.g. a hosted alternative to the stdio server the spec was
 * written for) must degrade to a connectivity-only success, not be
 * misreported as bad credentials.
 */
function finalizeMcpTestResponse(
  result: ExtendedMCPTestResponse,
  validation: CredentialValidation | undefined,
  redactionSources: (MCPServerConfig | undefined)[],
): ExtendedMCPTestResponse {
  const redacted = redactMcpTestResponse(result, redactionSources);
  if (
    redacted.ok &&
    validation &&
    redacted.tool_result &&
    redacted.tools.includes(validation.toolCall.name)
  ) {
    const credentialError = validation.interpret(redacted.tool_result);
    if (credentialError) {
      return {
        ok: false,
        error: credentialError,
        error_kind: "credentials",
      };
    }
  }
  return redacted;
}

function getMcpProbeOptions(): { host: string; apiKey?: string } {
  const active = getActiveBackend().backend;
  if (active.kind === "local") {
    const { host, apiKey } = getAgentServerClientOptions();
    return { host, ...(apiKey ? { apiKey } : {}) };
  }

  const localBackend = getRegisteredBackends().find(
    (backend) => backend.kind === "local" && backend.host,
  );
  if (localBackend) {
    return {
      host: localBackend.host.replace(/\/+$/, ""),
      ...(localBackend.apiKey ? { apiKey: localBackend.apiKey } : {}),
    };
  }
  throw new Error("OAuth authorization requires a reachable local backend.");
}

function createMcpProbeClient(): MCPClient {
  const { host, apiKey } = getMcpProbeOptions();
  return new MCPClient({
    host,
    ...(apiKey ? { apiKey } : {}),
    timeout: OAUTH_MCP_TEST_TIMEOUT_SECONDS * 1000 + 5000,
  });
}

function oauthStatusToTestResponse(
  status: MCPOAuthStatusResponse,
): ExtendedMCPTestResponse {
  if (status.status === "succeeded") {
    return {
      ok: true,
      tools: status.tools ?? [],
      ...(status.tool_result !== undefined && {
        tool_result: status.tool_result,
      }),
      ...(status.oauth_state !== undefined && {
        oauth_state: status.oauth_state,
      }),
    };
  }
  return {
    ok: false,
    error: status.error || "OAuth authorization did not complete",
    error_kind: status.error_kind || "unknown",
  };
}

const sleep = (ms: number) =>
  new Promise<void>((resolve) => {
    window.setTimeout(resolve, ms);
  });

class McpService {
  static async testServer(
    server: MCPServerConfig,
  ): Promise<ExtendedMCPTestResponse> {
    // The MCP connectivity-test endpoint lives on the local agent-server. It
    // spawns the configured stdio command / opens an SSE-or-SHTTP connection
    // from that process's environment. Cloud backends don't expose this
    // endpoint to the frontend — the MCP server would actually run inside the
    // cloud sandbox, which isn't reachable from the browser before the user
    // starts a conversation. Calling `getAgentServerClientOptions()` here for
    // a cloud-active session would throw `NoBackendAvailableError("No backend
    // is configured.")` and block the install flow entirely. Short-circuit
    // with a synthetic success so saving proceeds; any real connection
    // failure surfaces inside the conversation runtime instead.
    if (getActiveBackend().backend.kind === "cloud") {
      return { ok: true, tools: [] };
    }
    const validation = getCredentialValidationForServer(server);
    const { host, apiKey } = getAgentServerClientOptions();
    const client = new MCPClient({ host, ...(apiKey ? { apiKey } : {}) });
    try {
      const { request, substituted } = await buildMcpTestRequest(server);
      const result = (await client.testServer(
        request,
      )) as ExtendedMCPTestResponse;
      // Redact against both config forms: `server` may hold fresh plaintext
      // input, `substituted` the stored (encrypted) round-trip values.
      return finalizeMcpTestResponse(result, validation, [substituted, server]);
    } finally {
      client.close();
    }
  }

  static async startOAuth(
    server: MCPServerConfig,
  ): Promise<MCPOAuthStartResponse> {
    const client = createMcpProbeClient();
    try {
      return await McpService.startOAuthWithClient(client, server);
    } finally {
      client.close();
    }
  }

  static async getOAuthStatus(jobId: string): Promise<MCPOAuthStatusResponse> {
    const client = createMcpProbeClient();
    try {
      return await McpService.getOAuthStatusWithClient(client, jobId);
    } finally {
      client.close();
    }
  }

  static async submitOAuthCallback(
    jobId: string,
    callbackUrl: string,
  ): Promise<MCPOAuthStatusResponse> {
    const client = createMcpProbeClient();
    try {
      return await McpService.submitOAuthCallbackWithClient(
        client,
        jobId,
        callbackUrl,
      );
    } finally {
      client.close();
    }
  }

  static async authorizeOAuth(
    server: MCPServerConfig,
  ): Promise<ExtendedMCPTestResponse> {
    const validation = getCredentialValidationForServer(server);
    const finalize = (result: ExtendedMCPTestResponse) =>
      finalizeMcpTestResponse(result, validation, [server]);
    const popup = window.open("about:blank", "_blank");
    const client = createMcpProbeClient();
    try {
      const start = await McpService.startOAuthWithClient(client, server);
      if (!start.ok || !start.job_id || !start.authorization_url) {
        popup?.close();
        return finalize({
          ok: false,
          error: start.error || "Could not start OAuth authorization",
          error_kind: start.error_kind || "unknown",
        });
      }

      let status = await McpService.getOAuthStatusWithClient(
        client,
        start.job_id,
      );
      for (let attempt = 0; attempt < 20; attempt += 1) {
        if (status.status === "succeeded" || status.status === "failed") {
          popup?.close();
          return finalize(oauthStatusToTestResponse(status));
        }
        if (status.callback_ready) break;
        await sleep(250);
        status = await McpService.getOAuthStatusWithClient(
          client,
          start.job_id,
        );
      }

      if (popup) {
        popup.location.href = start.authorization_url;
      }

      for (
        let attempt = 0;
        attempt < OAUTH_MCP_TEST_TIMEOUT_SECONDS;
        attempt += 1
      ) {
        await sleep(1000);
        status = await McpService.getOAuthStatusWithClient(
          client,
          start.job_id,
        );
        if (status.status === "succeeded" || status.status === "failed") {
          popup?.close();
          return finalize(oauthStatusToTestResponse(status));
        }
      }

      return {
        ok: false,
        error: "OAuth authorization timed out",
        error_kind: "timeout",
      };
    } finally {
      client.close();
    }
  }

  private static async startOAuthWithClient(
    client: MCPClient,
    server: MCPServerConfig,
  ): Promise<MCPOAuthStartResponse> {
    const { request } = await buildMcpTestRequest(server);
    return client.startOAuth(request);
  }

  // typescript-client 1.36 types the OAuth probes with the generated
  // agent-server models, which describe the opaque `oauth_state` JSON blobs as
  // `unknown` rather than the recursive `MCPJsonValue` the local types use. The
  // wire shape is unchanged, so narrow back to the app's boundary type.
  private static async getOAuthStatusWithClient(
    client: MCPClient,
    jobId: string,
  ): Promise<MCPOAuthStatusResponse> {
    return (await client.getOAuthStatus(jobId)) as MCPOAuthStatusResponse;
  }

  private static async submitOAuthCallbackWithClient(
    client: MCPClient,
    jobId: string,
    callbackUrl: string,
  ): Promise<MCPOAuthStatusResponse> {
    return (await client.submitOAuthCallback(jobId, {
      callback_url: callbackUrl,
    })) as MCPOAuthStatusResponse;
  }
}

export default McpService;