// @ts-check
import https from 'https'
import fs from 'fs'

/**
 * Downloads a file from a URL with redirect handling
 * @param {string} url The URL to download from
 * @param {string} destinationPath The path to save the file to
 * @returns {Promise<void>} Promise that resolves when download is complete
 */
export async function downloadWithRedirects(url, destinationPath) {
  return new Promise((resolve, reject) => {
    const timeoutMs = 10 * 60 * 1000; // 10 minutes
    const timeout = setTimeout(() => {
      reject(new Error(`timeout（${timeoutMs / 1000} seconds）`));
    }, timeoutMs);

    // Use flag to prevent multiple resolve/reject calls
    let settled = false;

    const safeReject = (error) => {
      if (!settled) {
        settled = true;
        clearTimeout(timeout);
        reject(error);
      }
    };

    const safeResolve = () => {
      if (!settled) {
        settled = true;
        clearTimeout(timeout);
        resolve();
      }
    };

    const request = (url) => {
      // Support both http and https
      const httpModule = url.startsWith('https://') ? https : require('http');

      httpModule
        .get(url, (response) => {
          const statusCode = response.statusCode || 0;

          // Handle redirects (301, 302, 307, 308)
          if (statusCode >= 301 && statusCode <= 308 && response.headers.location) {
            const redirectUrl = response.headers.location;
            console.log(`Following redirect to: ${redirectUrl}`);
            request(redirectUrl);
            return;
          }
          if (statusCode !== 200) {
            safeReject(new Error(`Download failed: ${statusCode} ${response.statusMessage || 'Unknown error'}`))
            return
          }

          const file = fs.createWriteStream(destinationPath)
          let downloadedBytes = 0
          const expectedBytes = parseInt(response.headers['content-length'] || '0')
          const startTime = Date.now()
          let lastProgressTime = Date.now()

          if (expectedBytes > 0) {
            console.log(`Downloading ${(expectedBytes / 1024 / 1024).toFixed(2)} MB...`)
          } else {
            console.log('Downloading...')
          }

          response.on('data', (chunk) => {
            downloadedBytes += chunk.length

            // Show progress every 1 second
            const now = Date.now()
            if (now - lastProgressTime >= 1000) {
              if (expectedBytes > 0) {
                const percent = ((downloadedBytes / expectedBytes) * 100).toFixed(1)
                const speed = downloadedBytes / ((now - startTime) / 1000) / 1024 / 1024
                console.log(`Progress: ${percent}% (${(downloadedBytes / 1024 / 1024).toFixed(2)} MB) - ${speed.toFixed(2)} MB/s`)
              } else {
                console.log(`Downloaded: ${(downloadedBytes / 1024 / 1024).toFixed(2)} MB`)
              }
              lastProgressTime = now
            }
          })

          response.pipe(file)

          file.on('finish', () => {
            file.close(() => {
              // Don't proceed if already rejected (e.g., by error handler)
              if (settled) return;

              // Verify the download is complete
              if (expectedBytes > 0 && downloadedBytes !== expectedBytes) {
                try {
                  if (fs.existsSync(destinationPath)) {
                    fs.unlinkSync(destinationPath)
                  }
                } catch (err) {
                  console.error('Failed to delete incomplete file:', err);
                }
                safeReject(new Error(`Download incomplete: received ${downloadedBytes} bytes, expected ${expectedBytes}`))
                return
              }

              // Check if file exists and has size > 0
              try {

                if (fs.existsSync(destinationPath)) {
                  const stats = fs.statSync(destinationPath)
                  if (stats.size === 0) {
                    fs.unlinkSync(destinationPath)
                    safeReject(new Error('Downloaded file is empty'))
                    return
                  }
                  safeResolve()
                } else {
                  safeReject(new Error('Downloaded file does not exist'))
                }
              } catch (err) {
                safeReject(new Error(`Failed to verify download: ${err.message}`))

              }
            })
          })

          file.on('error', (err) => {
            try {
              if (fs.existsSync(destinationPath)) {
                fs.unlinkSync(destinationPath)
              }
            } catch (deleteErr) {
              console.error('Failed to delete file after error:', deleteErr);
            }
            safeReject(err)
          })
        })
        .on('error', (err) => {
          safeReject(err)
        })
    }
    request(url)
  })
}