'use strict'

import express from 'express'
import path from 'path'
import boom from 'boom'

import { imagesPath, imageServedUrl } from '../../config'
import { asyncMiddleware, checkSceneName, checkRequiredParameters, getSceneFilesData } from '../functions'

const router = express.Router()

/**
 * @api {get} /getImage?sceneName=:sceneName&imageQuality=:imageQuality Get an image from a scene
 * @apiVersion 0.1.0
 * @apiName GetImage
 * @apiGroup API
 *
 * @apiDescription Get an image from a scene with the required quality
 *
 * @apiParam {String} sceneName The selected scene
 * @apiParam {Number} imageQuality The required quality of the image
 *
 * @apiHeader (Response Headers) {String} Content-Type application/json; charset=utf-8
 *
 * @apiExample Usage example
 * curl -i -L -X GET "http://diran.univ-littoral.fr/api/getImage?sceneName=bathroom&imageQuality=200"
 *
 * @apiSuccess {String} data Path to the image
 * @apiSuccessExample {json} Success response example
 * HTTP/1.1 200 OK /api/getImage?sceneName=bathroom&imageQuality=200
 * {
 *   "data": "/api/images/bathroom/bathroom_00200.png"
 * }
 *
 * @apiError (Error 4xx) 400 Missing parameter(s)
 * @apiErrorExample {json} Missing parameter
 * HTTP/1.1 400 Bad Request
 * {
 *   "message": "Missing parameter(s). Required parameters : sceneName, imageQuality."
 * }
 *
 * @apiError (Error 4xx) 400 Invalid query parameter
 * @apiErrorExample {json} Invalid query parameter(s)
 * HTTP/1.1 400 Bad Request
 * {
 *   "message": "Invalid query parameter(s).",
 *   "data": [
 *     "The requested scene name \".//../\" is not valid.",
 *     "The specified quality is not an integer."
 *   ]
 * }
 *
 * @apiError (Error 4xx) 404 Quality not found
 * @apiErrorExample {json} Quality not found
 * HTTP/1.1 404 Not Found
 * {
 *   "message": "The requested quality (9999) was not found for the requested scene (bathroom)."
 * }
 *
 * @apiError (Error 5xx) 500 Can't access the `IMAGES_PATH` directory
 * @apiErrorExample {json} Images directory not accessible
 * HTTP/1.1 500 Internal Server Error
 * {
 *   "message": "Can't access the \"images\" directory. Check it exists and you have read permission on it"
 * }
 *
 * @apiError (Error 5xx) 500 Failed to parse a file's name
 * @apiErrorExample {json} Failed to parse a file's name
 * HTTP/1.1 500 Internal Server Error
 * {
 *   "message": "Failed to parse file names in the \"bathroom\"'s scene directory.",
 *   "data": [
 *     "The file name does not match convention (scene_000150.ext - /^(.*)?_([0-9]{2,})\\.(.*)$/) : \"bathroom_adz00020.png\".",
 *     "The file name does not match convention (scene_000150.ext - /^(.*)?_([0-9]{2,})\\.(.*)$/) : \"bathroom_adz00020.png\"."
 *   ]
 * }
 *
 */

/**
 * @typedef {Object} Image
 * @property {string} link the link (URL) to an image on the app
 * @property {string} path the path to the image in the file system
 * @property {string} fileName the name of the image
 * @property {string} sceneName the scene of the image
 * @property {number} quality the quality of the image
 * @property {string} ext the extension of the image
 */

/**
 * Get the link and path to an image
 * @param {string} sceneName the scene to get the image from
 * @param {number} qualityInt the requested quality
 * @returns {Promise<Image>} the link and path to the image
 */
export const getImage = async (sceneName, qualityInt) => {
  const sceneData = await getSceneFilesData(sceneName)

  // Search an image with the requested quality in the scene
  for (const [imageName, imageData] of sceneData.entries())
    if (qualityInt === imageData.quality)
      return {
        link: `${imageServedUrl}/${sceneName}/${imageName}`,
        path: path.resolve(imagesPath, sceneName, imageName),
        fileName: imageName,
        sceneName,
        quality: imageData.quality,
        ext: imageData.ext
      }

  // Image not found
  throw boom.notFound(`The requested quality (${qualityInt}) was not found for the requested scene (${sceneName}).`)
}

router.get('/', asyncMiddleware(async (req, res) => {
  // Check the request contains all the required parameters
  checkRequiredParameters(['sceneName', 'imageQuality'], req.query)

  const { sceneName, imageQuality } = req.query

  let errorList = []

  // Check the scene name is valid
  try {
    checkSceneName(sceneName)
  }
  catch (err) {
    errorList.push(err.message)
  }

  // Check `imageQuality` is an integer
  const qualityInt = parseInt(imageQuality, 10)
  if (isNaN(qualityInt)) errorList.push('The specified quality is not an integer.')

  // Check there is no errors with parameters
  if (errorList.length > 0)
    throw boom.badRequest('Invalid query parameter(s).', errorList)

  const { link } = await getImage(sceneName, qualityInt)
  res.json({ data: link })
}))

export default router