const fs = require("fs");
const boxIntersect = require("box-intersect");
const path = require('path');

const getLayers = (layers, boundingbox) => {
  if (boundingbox === undefined) {

    return new Promise((resolve, reject) => {
      fs.readFile("./assets/assets.json", (err, data) => {
        if (err) {
          reject();
        }
        let assets = JSON.parse(data);
        let requestedLayers = layers.split(",");
        assets = assets.filter(asset => requestedLayers.includes(asset.id));
        assets = assets.filter(asset => asset.scope == "public");
        resolve(assets);
      });
    });

  } else {

    return getIntersectingLayers(layers, boundingbox);

  }

}

const getIntersectingLayers = (layers,bb) => {

  return new Promise((resolve, reject) => {
    fs.readFile("./assets/assets.json", (err, data) => {
      if (err) {
        reject();
      }
      let assets = JSON.parse(data);
      let requestedBB = bb.split(",").map(token => parseFloat(token));
      let requestedLayers = layers.split(",");

      assets = assets.filter(asset => requestedLayers.includes(asset.id));
      assets = assets.filter(asset => asset.scope == "public");

      assets = assets.filter(asset => {

        let overlaps = boxIntersect([
          [...asset.boundingbox],
          [...requestedBB]
        ]);

        if (overlaps.length > 0) {
          return true;
        }
        return false;
      });

      resolve(assets);

    });
  });

}

const allLayersExist = (layers) => {

  if (!layers) return Promise.reject();

  return new Promise((resolve, reject) => {
    fs.readFile("./assets/assets.json", (err, data) => {
      if (err) {
        reject();
      }
      let assets = JSON.parse(data);
      layers = layers.split(",");
      layers.forEach(layer => {
        if (assets.findIndex(asset => asset.id == layer) == -1) {
          reject();
        }
      });
      resolve();
    });
  });

}

const getPublicLayers = () => {

  return new Promise((resolve, reject) => {
    fs.readFile("./assets/assets.json", (err, data) => {
      let assets = JSON.parse(data);
      assets = assets.filter(asset => asset.scope == "public");
      resolve(assets);
    });
  });

}

const isPublic = (url) => {

  return new Promise((resolve, reject) => {
    fs.readFile("./assets/assets.json", (err, data) => {
      let assets = JSON.parse(data);
      assets = assets.filter(asset => {
        let parentDir = path.dirname(asset.url);
        return !path.relative(parentDir, url).startsWith("..");
      });
      if (assets.length == 0) {
        resolve(false);
        return;
      }
      if (!assets[0].scope == "public") {
        resolve(false);
        return;
      }
      resolve(true);
    });
  });

}

module.exports = { getLayers, allLayersExist, getPublicLayers, isPublic };