import { execSync, spawn } from 'node:child_process';
import { existsSync } from 'node:fs';
import { join } from 'node:path';
import { app } from 'electron';
import logManager from '@electron/service/logger';
import { getUvMirrorEnv } from './uv-env';

function getBundledUvPath(): string {
  const platform = process.platform;
  const arch = process.arch;
  const target = `${platform}-${arch}`;
  const binName = platform === 'win32' ? 'uv.exe' : 'uv';

  if (app.isPackaged) {
    return join(process.resourcesPath, 'bin', binName);
  }

  return join(process.cwd(), 'resources', 'bin', target, binName);
}

function findUvInPathSync(): boolean {
  try {
    const command = process.platform === 'win32' ? 'where.exe uv' : 'which uv';
    execSync(command, { stdio: 'ignore', timeout: 5000, windowsHide: true });
    return true;
  } catch {
    return false;
  }
}

function resolveUvBin(): { bin: string; source: 'bundled' | 'path' | 'bundled-fallback' } {
  const bundled = getBundledUvPath();

  if (app.isPackaged) {
    if (existsSync(bundled)) {
      return { bin: bundled, source: 'bundled' };
    }
    logManager.warn(`Bundled uv binary not found at ${bundled}, falling back to system PATH`);
  }

  if (findUvInPathSync()) {
    return { bin: 'uv', source: 'path' };
  }

  if (existsSync(bundled)) {
    return { bin: bundled, source: 'bundled-fallback' };
  }

  return { bin: 'uv', source: 'path' };
}

export async function checkUvInstalled(): Promise<boolean> {
  const { bin, source } = resolveUvBin();
  if (source === 'bundled' || source === 'bundled-fallback') {
    return existsSync(bin);
  }
  return findUvInPathSync();
}

export async function installUv(): Promise<void> {
  const isAvailable = await checkUvInstalled();
  if (!isAvailable) {
    const bin = getBundledUvPath();
    throw new Error(`uv not found in system PATH and bundled binary missing at ${bin}`);
  }
  logManager.info('uv is available and ready to use');
}

export async function isPythonReady(): Promise<boolean> {
  const { bin: uvBin } = resolveUvBin();

  return await new Promise<boolean>((resolve) => {
    try {
      const child = spawn(uvBin, ['python', 'find', '3.12'], {
        windowsHide: true,
      });
      child.on('close', (code) => resolve(code === 0));
      child.on('error', () => resolve(false));
    } catch {
      resolve(false);
    }
  });
}

async function runPythonInstall(
  uvBin: string,
  env: Record<string, string | undefined>,
  label: string,
): Promise<void> {
  return await new Promise<void>((resolve, reject) => {
    const stderrChunks: string[] = [];
    const stdoutChunks: string[] = [];

    const child = spawn(uvBin, ['python', 'install', '3.12'], {
      env,
      windowsHide: true,
    });

    child.stdout?.on('data', (data) => {
      const line = data.toString().trim();
      if (line) {
        stdoutChunks.push(line);
        logManager.debug(`[python-setup:${label}] stdout: ${line}`);
      }
    });

    child.stderr?.on('data', (data) => {
      const line = data.toString().trim();
      if (line) {
        stderrChunks.push(line);
        logManager.info(`[python-setup:${label}] stderr: ${line}`);
      }
    });

    child.on('close', (code) => {
      if (code === 0) {
        resolve();
        return;
      }

      const stderr = stderrChunks.join('\n');
      const stdout = stdoutChunks.join('\n');
      const detail = stderr || stdout || '(no output captured)';
      reject(new Error(
        `Python installation failed with code ${code} [${label}]\n` +
        `  uv binary: ${uvBin}\n` +
        `  platform: ${process.platform}/${process.arch}\n` +
        `  output: ${detail}`,
      ));
    });

    child.on('error', (error) => {
      reject(new Error(
        `Python installation spawn error [${label}]: ${error.message}\n` +
        `  uv binary: ${uvBin}\n` +
        `  platform: ${process.platform}/${process.arch}`,
      ));
    });
  });
}

export async function setupManagedPython(): Promise<void> {
  const { bin: uvBin, source } = resolveUvBin();
  const uvEnv = await getUvMirrorEnv();
  const hasMirror = Object.keys(uvEnv).length > 0;

  logManager.info(
    `Setting up managed Python 3.12 ` +
    `(uv=${uvBin}, source=${source}, arch=${process.arch}, mirror=${hasMirror})`,
  );

  const baseEnv: Record<string, string | undefined> = { ...process.env };

  try {
    await runPythonInstall(uvBin, { ...baseEnv, ...uvEnv }, hasMirror ? 'mirror' : 'default');
  } catch (firstError) {
    logManager.warn('Python install attempt 1 failed:', firstError);

    if (!hasMirror) {
      throw firstError;
    }

    logManager.info('Retrying Python install without mirror...');
    try {
      await runPythonInstall(uvBin, baseEnv, 'no-mirror');
    } catch (secondError) {
      logManager.error('Python install attempt 2 (no mirror) also failed:', secondError);
      throw secondError;
    }
  }

  try {
    const findPath = await new Promise<string>((resolve) => {
      const child = spawn(uvBin, ['python', 'find', '3.12'], {
        env: { ...process.env, ...uvEnv },
        windowsHide: true,
      });
      let output = '';
      child.stdout?.on('data', (data) => {
        output += data;
      });
      child.on('close', () => resolve(output.trim()));
      child.on('error', () => resolve(''));
    });

    if (findPath) {
      logManager.info(`Managed Python 3.12 installed at: ${findPath}`);
    }
  } catch (error) {
    logManager.warn('Could not determine Python path after install:', error);
  }
}