const Router = require('koa-router')
const r = new Router()
const gm = require('gm')
const config = require('@config/index')
const fs = require('fs')
const path = require('path')

const getImageToRes = async (c, n) => {
  let filepath = path.resolve(config.image_root, c.state.file)
  console.log(filepath)
  try {
    fs.accessSync(filepath)
  } catch (err) {
    c.throw(404, 'image not found')
  }

  let buf = null

  let imgSize = await getImageSize(filepath)
  if (imgSize === null) c.throw(500)
  if (c.state.ori === true) {
    // max 1024x1024
    if (imgSize.width > 1024 || imgSize.height > 1024) {
      buf = await resizeImage(filepath, 1024)
      if (buf === null) c.throw(500)
    }
  } else {
    // max 240x240
    if (imgSize.width > 240 || imgSize.height > 240) {
      buf = await resizeImage(filepath, 240)
      if (buf === null) c.throw(500)
    }
  }

  if (buf === null) {
    let format = await getImageFormat(filepath)
    if (format === null) c.throw(500)
    if (format !== 'JPEG') {
      buf = await convertToJPEG(filepath)
      if (buf === null) c.throw(500)
    } else {
      buf = fs.readFileSync(filepath)
    }
  }

  c.type = 'image/jpeg'
  c.body = buf
}

const convertToJPEG = async (file = null) => {
  let buf = await new Promise((resolve) => {
    gm(file).toBuffer('JPEG', (err, buf) => {
      resolve(err ? null : buf)
    })
  })
  return buf
}

const getImageFormat = async (file = null) => {
  let format = await new Promise((resolve) => {
    gm(file).format((err, format) => {
      resolve(err ? null : format)
    })
  })
  return format
}

const getImageSize = async (file = null) => {
  let size = await new Promise((resolve) => {
    gm(file).size((err, val) => {
      resolve(err ? null : val)
    })
  })
  return size
}

const resizeImage = async (file = null, size = 1024) => {
  let buf = await new Promise((resolve) => {
    gm(file).resize(size, size).toBuffer('JPEG', (err, buf) => {
      resolve(err ? null : buf)
    })
  })
  return buf
}

r.get('/image/origin/:name', async (c, n) => {
  c.state.ori = true
  let name = c.params.name || ''
  if (typeof name !== 'string' || name.trim().length === 0) c.throw('image name not valid', 400)
  c.state.file = name
  return n()
}, getImageToRes)

r.get('/image/thumbnail/:name', async (c, n) => {
  c.state.ori = false
  let name = c.params.name || ''
  if (typeof name !== 'string' || name.trim().length === 0) c.throw('image name not valid', 400)
  c.state.file = name
  return n()
}, getImageToRes)

r.use('/web', require('./web').routes())
r.use('/api', require('./api').routes())
r.use('/line', require('./line').routes())
r.use('/google', require('./google').routes())
r.use('/twitch', require('./twitch').routes())

module.exports = r