import { spawn } from 'node:child_process';
import { z } from 'zod';
import type { ToolDef } from '../types.js';

export const GetCodeMapInput = z.object({
  directory: z.string().optional().describe('Directory to scan (defaults to project root)'),
  compress: z.boolean().optional().describe('Apply DCP compression if payload exceeds threshold (default: true)'),
});
export type GetCodeMapInputT = z.infer<typeof GetCodeMapInput>;

const DESCRIPTION =
  'DCP-compressed codebase context map. Returns filenames, sizes, import relationships in a compressed format. ' +
  'Use compress=false for full detail, compress=true (default) for token-efficient overview.';

const BOOCONTEXT_PATH = '/opt/forks/boocontext/dist/standalone.js';
const TOOL_TIMEOUT_MS = 30_000;
const MAX_RESULT_BYTES = 32_768;

export interface CodeMapResponse {
  result: string;
  truncated: boolean;
}

/**
 * Calls the boocontext MCP server over stdio JSON-RPC to invoke
 * the boocontext_map tool. Spawns the standalone binary, sends
 * initialize + tools/call, collects NDJSON responses, and kills
 * the child process.
 */
function callBoocontextMap(args: Record<string, unknown>): Promise<CodeMapResponse> {
  return new Promise((resolve, reject) => {
    const child = spawn('node', [BOOCONTEXT_PATH], {
      stdio: ['pipe', 'pipe', 'pipe'],
    });

    let stdoutBuf = '';
    const lines: string[] = [];
    let timedOut = false;
    let resolved = false;

    const timer = setTimeout(() => {
      timedOut = true;
      child.kill('SIGKILL');
      reject(new Error(`boocontext MCP call timed out after ${TOOL_TIMEOUT_MS}ms`));
    }, TOOL_TIMEOUT_MS);

    function tryParse(): void {
      if (resolved || timedOut) return;

      // Accumulate complete NDJSON lines
      const parts = stdoutBuf.split('\n');
      stdoutBuf = parts.pop()! ?? '';
      for (const p of parts) {
        const t = p.trim();
        if (t) lines.push(t);
      }

      // Need at least 2 responses: initialize + tools/call
      if (lines.length < 2) return;

      resolved = true;
      clearTimeout(timer);
      child.kill();

      try {
        const callResponse = JSON.parse(lines[1]!);
        if (callResponse.error) {
          reject(new Error(`MCP error: ${callResponse.error.message}`));
          return;
        }

        const content = callResponse.result?.content;
        if (!content?.[0]?.text) {
          reject(new Error('Unexpected MCP response shape — missing content[0].text'));
          return;
        }

        // content[0].text is JSON-stringified VerdictEnvelope from boocontext
        const envelope = JSON.parse(content[0].text as string);
        const details = envelope.details;

        let result: string;
        if (details && typeof details === 'object' && 'data' in details) {
          // DcpEnvelope shape: { compressed, originalLength, compressedLength, data }
          if (details.compressed) {
            // Return the full DcpEnvelope as JSON so the LLM can pass it
            // transparently to a decompression step
            result = JSON.stringify(details);
          } else {
            // Uncompressed — data is the raw output
            result = details.data;
          }
        } else {
          result = JSON.stringify(details ?? envelope);
        }

        const truncated = Buffer.byteLength(result, 'utf-8') > MAX_RESULT_BYTES;
        if (truncated) {
          result = result.substring(0, MAX_RESULT_BYTES);
        }

        resolve({ result, truncated });
      } catch (e: any) {
        reject(new Error(`Failed to parse boocontext response: ${e.message}`));
      }
    }

    child.stdout!.on('data', (chunk: Buffer) => {
      if (timedOut) return;
      stdoutBuf += chunk.toString('utf-8');
      tryParse();
    });

    child.stderr!.on('data', (_chunk: Buffer) => {
      // Captured but not surfaced — logged only on parse failure
    });

    child.on('error', (err: Error) => {
      clearTimeout(timer);
      if (!resolved) {
        resolved = true;
        reject(new Error(`boocontext spawn failed: ${err.message}`));
      }
    });

    child.on('close', () => {
      clearTimeout(timer);
      if (!resolved && !timedOut) {
        tryParse();
        if (!resolved) {
          resolved = true;
          reject(new Error('boocontext process closed without producing a valid response'));
        }
      }
    });

    // Step 1: initialize
    child.stdin!.write(
      JSON.stringify({ jsonrpc: '2.0', id: 1, method: 'initialize' }) + '\n',
    );

    // Step 2: tools/call for boocontext_map
    child.stdin!.write(
      JSON.stringify({
        jsonrpc: '2.0',
        id: 2,
        method: 'tools/call',
        params: { name: 'boocontext_map', arguments: args },
      }) + '\n',
    );
  });
}

export const getCodeMap: ToolDef<GetCodeMapInputT> = {
  name: 'get_code_map',
  description: DESCRIPTION,
  inputSchema: GetCodeMapInput,
  jsonSchema: {
    type: 'function',
    function: {
      name: 'get_code_map',
      description: DESCRIPTION,
      parameters: {
        type: 'object',
        properties: {
          directory: { type: 'string', description: 'Directory to scan (defaults to project root)' },
          compress: {
            type: 'boolean',
            description: 'Apply DCP compression if payload exceeds threshold (default: true)',
          },
        },
        additionalProperties: false,
      },
    },
  },
  async execute(input, projectRoot): Promise<CodeMapResponse> {
    return callBoocontextMap({
      directory: input.directory ?? projectRoot,
      compress: input.compress ?? true,
    });
  },
};

export async function executeGetCodeMap(
  input: GetCodeMapInputT,
  projectRoot: string,
): Promise<CodeMapResponse> {
  return callBoocontextMap({
    directory: input.directory ?? projectRoot,
    compress: input.compress ?? true,
  });
}