import { spawn } from "child_process";

export interface ClaudeResult {
  sessionId: string;
  result: string;
}

interface CliJsonResult {
  result?: string;
  session_id?: string;
  is_error?: boolean;
}

function runClaude(args: string[], cwd: string): Promise<string> {
  return new Promise((resolve, reject) => {
    const proc = spawn("npx", ["--yes", "@anthropic-ai/claude-code", ...args], {
      cwd,
      shell: true,
      env: { ...process.env },
    });

    let stdout = "";
    let stderr = "";

    proc.stdout.on("data", (data: Buffer) => {
      stdout += data.toString();
    });

    proc.stderr.on("data", (data: Buffer) => {
      stderr += data.toString();
    });

    proc.on("close", (code: number | null) => {
      if (code !== 0 && !stdout) {
        reject(new Error(stderr || `claude exited with code ${code}`));
      } else {
        resolve(stdout);
      }
    });

    proc.on("error", reject);
  });
}

const APPEND_PROMPT = "Always respond in Russian. Be concise.";

export class ClaudeService {
  async createSession(prompt: string, cwd: string): Promise<ClaudeResult> {
    const raw = await runClaude(
      ["-p", prompt, "--output-format", "json", "--dangerously-skip-permissions", "--append-system-prompt", APPEND_PROMPT],
      cwd,
    );

    const parsed = JSON.parse(raw.trim().split("\n").pop()!) as CliJsonResult;

    return {
      sessionId: parsed.session_id ?? "",
      result: parsed.result ?? "",
    };
  }

  async sendMessage(prompt: string, sessionId: string): Promise<string> {
    const raw = await runClaude(
      ["-p", prompt, "--output-format", "json", "--resume", sessionId, "--dangerously-skip-permissions", "--append-system-prompt", APPEND_PROMPT],
      process.cwd(),
    );

    const parsed = JSON.parse(raw.trim().split("\n").pop()!) as CliJsonResult;
    return parsed.result ?? "";
  }
}