import { Context } from 'elysia'
import axios from 'axios'
import sharp from 'sharp'

const parseIntParam = (value: string): number | null => {
  const parsed = Number(value)
  if (isNaN(parsed)) return null
  return parsed
}

const clamp = (n: number): number => Math.max(0, Math.min(255, n))

const recolor = async (imgBuffer: Buffer, color: number[]): Promise<Buffer> => {
  const [r, g, b] = color

  const image = sharp(imgBuffer)

  const raw = await image
    .ensureAlpha()
    .raw()
    .toBuffer({ resolveWithObject: true })

  const pixels = raw.data
  const { width: w, height: h } = raw.info

  for (let i = 0; i < pixels.length; i += 4) {
    pixels[i] = Math.round((pixels[i] / 255) * r)
    pixels[i + 1] = Math.round((pixels[i + 1] / 255) * g)
    pixels[i + 2] = Math.round((pixels[i + 2] / 255) * b)
  }

  return sharp(pixels, {
    raw: { width: w, height: h!, channels: 4 }
  })
    .png()
    .toBuffer()
}

export const handler = async (context: Context) => {
  let icon = Math.max(-4, Math.min(8, parseIntParam(context.query.icon) ?? 1))
  let overlay = Math.max(
    0,
    Math.min(14, parseIntParam(context.query.overlay) ?? 0)
  )
  const birdColor = [
    clamp(parseIntParam(context.query.birdR) ?? 255),
    clamp(parseIntParam(context.query.birdG) ?? 255),
    clamp(parseIntParam(context.query.birdB) ?? 255)
  ]
  const overlayColor = [
    clamp(parseIntParam(context.query.overlayR) ?? 255),
    clamp(parseIntParam(context.query.overlayG) ?? 255),
    clamp(parseIntParam(context.query.overlayB) ?? 255)
  ]

  let overlayImg: Buffer | null = null
  let iconImg: Buffer | null = null
  if (overlay !== 0) {
    try {
      const result = await axios.get(
        `https://games-r2.lncvrt.xyz/game-assets/berrydash/overlays/overlay_${overlay}.png`,
        { responseType: 'arraybuffer' }
      )
      overlayImg = Buffer.from(result.data)
    } catch {}
  }
  try {
    const result = await axios.get(
      `https://games-r2.lncvrt.xyz/game-assets/berrydash/icons/bird_${icon}.png`,
      { responseType: 'arraybuffer' }
    )
    iconImg = Buffer.from(result.data)
  } catch {}
  if (!iconImg) {
    return new Response(null, { status: 400 })
  }

  let result = await recolor(iconImg, birdColor)

  if (overlayImg) {
    const recoloredOverlay = await recolor(overlayImg, overlayColor)

    result = await sharp(result)
      .composite([
        {
          input: recoloredOverlay,
          top: overlay == 8 ? 25 : 13,
          left: overlay == 8 ? 10 : 15,
          blend: 'over'
        }
      ])
      .png()
      .toBuffer()
  }

  return new Response(result.buffer as ArrayBuffer, {
    headers: { 'Content-Type': 'image/png' }
  })
}