import { promises as fs } from 'fs'
import path from 'path'

export async function imageExists(imagePath: string): Promise<boolean> {
  try {
    const fullPath = path.join(process.cwd(), 'public', imagePath)
    await fs.access(fullPath)
    return true
  } catch {
    return false
  }
}

export async function getImageDimensions(
  imagePath: string
): Promise<{ width: number; height: number } | null> {
  try {
    const fullPath = path.join(process.cwd(), 'public', imagePath)
    const buffer = await fs.readFile(fullPath)

    if (imagePath.endsWith('.png')) {
      const width = buffer.readUInt32BE(16)
      const height = buffer.readUInt32BE(20)
      return { width, height }
    }

    if (imagePath.endsWith('.jpg') || imagePath.endsWith('.jpeg')) {
      let offset = 2
      while (offset < buffer.length) {
        if (buffer[offset] !== 0xff) break

        const marker = buffer[offset + 1]
        if (marker === 0xc0 || marker === 0xc2) {
          const height = buffer.readUInt16BE(offset + 5)
          const width = buffer.readUInt16BE(offset + 7)
          return { width, height }
        }

        offset += 2 + buffer.readUInt16BE(offset + 2)
      }
    }

    return null
  } catch {
    return null
  }
}

export function getOptimizedImageUrl(
  src: string,
  width?: number,
  height?: number,
  quality: number = 75
): string {
  const params = new URLSearchParams()

  if (width) params.set('w', width.toString())
  if (height) params.set('h', height.toString())
  params.set('q', quality.toString())

  const queryString = params.toString()
  return queryString ? `${src}?${queryString}` : src
}

export async function getImageWithPlaceholder(
  imagePath: string
): Promise<{ src: string; width: number; height: number; placeholder?: string }> {
  const dimensions = await getImageDimensions(imagePath)

  if (!dimensions) {
    return {
      src: imagePath,
      width: 800,
      height: 600,
    }
  }

  const placeholder = `data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='${dimensions.width}' height='${dimensions.height}'%3E%3Crect width='${dimensions.width}' height='${dimensions.height}' fill='%2318181b'/%3E%3C/svg%3E`

  return {
    src: imagePath,
    ...dimensions,
    placeholder,
  }
}