'use strict';

////////////////////////////////////////////////////////////////////////////////
/// @brief Foxx service store
///
/// @file
///
/// DISCLAIMER
///
/// Copyright 2015 triagens GmbH, Cologne, Germany
///
/// Licensed under the Apache License, Version 2.0 (the "License");
/// you may not use this file except in compliance with the License.
/// You may obtain a copy of the License at
///
///     http://www.apache.org/licenses/LICENSE-2.0
///
/// Unless required by applicable law or agreed to in writing, software
/// distributed under the License is distributed on an "AS IS" BASIS,
/// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
/// See the License for the specific language governing permissions and
/// limitations under the License.
///
/// Copyright holder is triAGENS GmbH, Cologne, Germany
///
/// @author Dr. Frank Celler, Michael Hackstein
/// @author Copyright 2015, triAGENS GmbH, Cologne, Germany
////////////////////////////////////////////////////////////////////////////////



var checkedFishBowl = false;


const arangodb = require("@arangodb");
const plainServerVersion = arangodb.plainServerVersion;
const db = arangodb.db;
const download = require("internal").download;
const fs = require("fs");
const throwDownloadError = arangodb.throwDownloadError;
const utils = require("@arangodb/foxx/manager-utils");
const semver = require('semver');


////////////////////////////////////////////////////////////////////////////////
/// @brief returns the fishbowl repository
////////////////////////////////////////////////////////////////////////////////

function getFishbowlUrl () {
  return "arangodb/foxx-apps";
}

////////////////////////////////////////////////////////////////////////////////
/// @brief returns the fishbowl collection
///
/// this will create the collection if it does not exist. this is better than
/// needlessly creating the collection for each database in case it is not
/// used in context of the database.
////////////////////////////////////////////////////////////////////////////////

var getFishbowlStorage = function() {

  var c = db._collection('_fishbowl');
  if (c ===  null) {
    c = db._create('_fishbowl', { isSystem : true });
  }

  if (c !== null && ! checkedFishBowl) {
    // ensure indexes
    c.ensureFulltextIndex("description");
    c.ensureFulltextIndex("name");
    checkedFishBowl = true;
  }

  return c;
};

////////////////////////////////////////////////////////////////////////////////
/// @brief comparator for services
////////////////////////////////////////////////////////////////////////////////

var compareServices =  function(l, r) {
  var left = l.name.toLowerCase();
  var right = r.name.toLowerCase();

  if (left < right) {
    return -1;
  }

  if (right < left) {
    return 1;
  }

  return 0;
};

////////////////////////////////////////////////////////////////////////////////
/// @brief updates the fishbowl from a zip archive
////////////////////////////////////////////////////////////////////////////////

var updateFishbowlFromZip = function(filename) {
  var i;
  var tempPath = fs.getTempPath();
  var toSave = [ ];

  try {
    fs.makeDirectoryRecursive(tempPath);
    var root = fs.join(tempPath, "foxx-apps-master/applications");

    // remove any previous files in the directory
    fs.listTree(root).forEach(function (file) {
      if (file.match(/\.json$/)) {
        try {
          fs.remove(fs.join(root, file));
        }
        catch (ignore) {
        }
      }
    });

    fs.unzipFile(filename, tempPath, false, true);

    if (! fs.exists(root)) {
      throw new Error("'applications' directory is missing in foxx-apps-master, giving up");
    }

    var m = fs.listTree(root);
    var reSub = /(.*)\.json$/;
    var f, match, service, desc;

    for (i = 0;  i < m.length;  ++i) {
      f = m[i];
      match = reSub.exec(f);
      if (match === null) {
        continue;
      }

      service = fs.join(root, f);

      try {
        desc = JSON.parse(fs.read(service));
      }
      catch (err1) {
        arangodb.printf("Cannot parse description for service '" + f + "': %s\n", String(err1));
        continue;
      }

      desc._key = match[1];

      if (! desc.hasOwnProperty("name")) {
        desc.name = match[1];
      }

      toSave.push(desc);
    }

    if (toSave.length > 0) {
      var fishbowl = getFishbowlStorage();

      db._executeTransaction({
        collections: {
          write: fishbowl.name()
        },
        action: function (params) {
          var c = require("internal").db._collection(params.collection);
          c.truncate();

          params.services.forEach(function(service) {
            c.save(service);
          });
        },
        params: {
          services: toSave,
          collection: fishbowl.name()
        }
      });

      arangodb.printf("Updated local repository information with %d service(s)\n",
                      toSave.length);
    }
  }
  catch (err) {
    if (tempPath !== undefined && tempPath !== "") {
      try {
        fs.removeDirectoryRecursive(tempPath);
      }
      catch (ignore) {
      }
    }

    throw err;
  }
};


////////////////////////////////////////////////////////////////////////////////
/// @brief returns the search result for FOXX services
////////////////////////////////////////////////////////////////////////////////

var searchJson = function (name) {
  var fishbowl = getFishbowlStorage();

  if (fishbowl.count() === 0) {
    arangodb.print("Repository is empty, please use 'update'");

    return [];
  }

  var docs;

  if (name === undefined || (typeof name === "string" && name.length === 0)) {
    docs = fishbowl.toArray();
  }
  else {
    name = name.replace(/[^a-zA-Z0-9]/g, ' ');

    // get results by looking in "description" attribute
    docs = fishbowl.fulltext("description", "prefix:" + name).toArray();

    // build a hash of keys
    var i;
    var keys = { };

    for (i = 0; i < docs.length; ++i) {
      keys[docs[i]._key] = 1;
    }

    // get results by looking in "name" attribute
    var docs2= fishbowl.fulltext("name", "prefix:" + name).toArray();

    // merge the two result sets, avoiding duplicates
    for (i = 0; i < docs2.length; ++i) {
      if (!keys.hasOwnProperty(docs2[i]._key)) {
        docs.push(docs2[i]);
      }

    }
  }

  return docs;
};


////////////////////////////////////////////////////////////////////////////////
/// @brief searchs for an available FOXX services
////////////////////////////////////////////////////////////////////////////////

var search = function (name) {
  var docs = searchJson(name);

  arangodb.printTable(
    docs.sort(compareServices),
    [ "name", "author", "description" ],
    {
      prettyStrings: true,
      totalString: "%s service(s) found",
      emptyString: "no services found",
      rename: {
        name : "Name",
        author : "Author",
        description : "Description"
      }
    }
  );
};

////////////////////////////////////////////////////////////////////////////////
/// @brief extracts the highest version number from the document
////////////////////////////////////////////////////////////////////////////////

function extractMaxVersion(matchEngine, versionDoc) {
  let serverVersion = plainServerVersion();
  let versions = Object.keys(versionDoc);
  versions.sort(semver.compare).reverse();
  let fallback;

  for (let version of versions) {
    let info = versionDoc[version];
    if (!info.engines || Object.keys(info.engines).length === 0) {
      // No known compatibility requirements indicated: use as last resort
      if (!matchEngine) {
        return version;
      }
      if (!fallback) {
        fallback = version;
      }
      continue;
    }
    let versionRange = info.engines.arangodb;
    if (!versionRange || semver.outside(serverVersion, versionRange, '<')) {
      // Explicitly backwards-incompatible with the server version: ignore
      continue;
    }
    if (!matchEngine || semver.satisfies(serverVersion, versionRange)) {
      return version;
    }
  }

  return fallback;
}

////////////////////////////////////////////////////////////////////////////////
/// @brief returns all available FOXX services
////////////////////////////////////////////////////////////////////////////////

function availableJson(matchEngine) {
  let fishbowl = getFishbowlStorage();
  let cursor = fishbowl.all();
  let result = [];

  while (cursor.hasNext()) {
    let doc = cursor.next();
    let latestVersion = extractMaxVersion(matchEngine, doc.versions);

    if (latestVersion) {
      let serverVersion = plainServerVersion();
      let versionInfo = doc.versions[latestVersion];
      let legacy = Boolean(
        versionInfo.engines
        && versionInfo.engines.arangodb
        && !semver.satisfies(serverVersion, versionInfo.engines.arangodb)
      );
      let res = {
        name: doc.name,
        description: doc.description || "",
        author: doc.author || "",
        latestVersion,
        legacy
      };

      result.push(res);
    }
  }

  return result;
}

////////////////////////////////////////////////////////////////////////////////
/// @brief updates the repository
////////////////////////////////////////////////////////////////////////////////


var update = function() {
  var url = utils.buildGithubUrl(getFishbowlUrl());
  var filename = fs.getTempFile("downloads", false);
  var path = fs.getTempFile("zip", false);

  try {
    var result = download(url, "", {
      method: "get",
      followRedirects: true,
      timeout: 30
    }, filename);

    if (result.code < 200 || result.code > 299) {
      throwDownloadError("Github download from '" + url + "' failed with error code " + result.code);
    }

    updateFishbowlFromZip(filename);

    filename = undefined;
  }
  catch (err) {
    if (filename !== undefined && fs.exists(filename)) {
      fs.remove(filename);
    }

    try {
      fs.removeDirectoryRecursive(path);
    }
    catch (ignore) {
    }

    throw err;
  }
};

////////////////////////////////////////////////////////////////////////////////
/// @brief prints all available FOXX services
////////////////////////////////////////////////////////////////////////////////

var available = function (matchEngine) {
  var list = availableJson(matchEngine);

  arangodb.printTable(
    list.sort(compareServices),
    [ "name", "author", "description", "latestVersion" ],
    {
      prettyStrings: true,
      totalString: "%s service(s) found",
      emptyString: "no services found, please use 'update'",
      rename: {
        "name" : "Name",
        "author" : "Author",
        "description" : "Description",
        "latestVersion" : "Latest Version"
      }
    }
  );
};

////////////////////////////////////////////////////////////////////////////////
/// @brief gets json-info for an available FOXX service
////////////////////////////////////////////////////////////////////////////////

var infoJson = function (name) {
  utils.validateServiceName(name);

  var fishbowl = getFishbowlStorage();

  if (fishbowl.count() === 0) {
    arangodb.print("Repository is empty, please use 'update'");
    return;
  }

  var desc = db._query(
    "FOR u IN @@storage FILTER u.name == @name OR @name in u.aliases RETURN DISTINCT u",
    { '@storage': fishbowl.name(), 'name': name }).toArray();

  if (desc.length === 0) {
    arangodb.print("No service '" + name + "' available, please try 'search'");
    return;
  }
  else if (desc.length > 1) {
    arangodb.print("Multiple services are named '" + name + "', please try 'search'");
    return;
  }
  else {
    return desc[0];
  }
};

////////////////////////////////////////////////////////////////////////////////
/// @brief create a download URL for the given service information
////////////////////////////////////////////////////////////////////////////////

var installationInfo = function(serviceInfo) {

  // TODO Validate
  let infoSplit = serviceInfo.split(":");
  let name = infoSplit[0];
  let version = infoSplit[1];
  let storeInfo = infoJson(name);

  if (storeInfo === undefined) {
    throw new Error('Service not found');
  }

  let versions = storeInfo.versions;
  let versionInfo;

  if (version === undefined) {
    let maxVersion = extractMaxVersion(true, versions);

    if (! maxVersion) {
      maxVersion = extractMaxVersion(false, versions);
    }

    if (! maxVersion) {
      throw new Error('No available version');
    }

    versionInfo = versions[maxVersion];
  }
  else {
    if (!versions.hasOwnProperty(version)) {
      throw new Error('Unknown version');
    }

    versionInfo = versions[version];
  }

  let url;
  if (!versionInfo.type) {
    url = versionInfo.location;
  } else if (versionInfo.type === 'github') {
    url = utils.buildGithubUrl(versionInfo.location, versionInfo.tag);
  } else {
    throw new Error(`Unknown location type ${versionInfo.type}`);
  }
  const manifest = {name};

  if (serviceInfo.author) {
    manifest.author = serviceInfo.author;
  }
  if (serviceInfo.description) {
    manifest.description = serviceInfo.description;
  }
  if (serviceInfo.license) {
    manifest.license = serviceInfo.license;
  }
  if (serviceInfo.keywords) {
    manifest.keywords = serviceInfo.keywords;
  }
  if (versionInfo.engines) {
    manifest.engines = versionInfo.engines;
  }
  if (versionInfo.provides) {
    manifest.provides = versionInfo.provides;
  }

  return {url, manifest};
};

////////////////////////////////////////////////////////////////////////////////
/// @brief prints info for an available FOXX service
////////////////////////////////////////////////////////////////////////////////

var info = function (name) {
  var desc = infoJson(name);
  arangodb.printf("Name:        %s\n", desc.name);

  if (desc.hasOwnProperty('author')) {
    arangodb.printf("Author:      %s\n", desc.author);
  }

  var isSystem = desc.hasOwnProperty('isSystem') && desc.isSystem;
  arangodb.printf("System:      %s\n", JSON.stringify(isSystem));

  if (desc.hasOwnProperty('description')) {
    arangodb.printf("Description: %s\n\n", desc.description);
  }

  var header = false;
  var versions = Object.keys(desc.versions);
  versions.sort(semver.compare);

  versions.forEach(function (v) {
    var version = desc.versions[v];

    if (! header) {
      arangodb.print("Versions:");
      header = true;
    }

    if (version.type === "github") {
      if (version.hasOwnProperty("tag")) {
        arangodb.printf('%s: fetch github "%s" "%s"\n', v, version.location, version.tag);
      }
      else if (v.hasOwnProperty("branch")) {
        arangodb.printf('%s: fetch github "%s" "%s"\n', v, version.location, version.branch);
      }
      else {
        arangodb.printf('%s: fetch "github" "%s"\n', v, version.location);
      }
    }
  });

  arangodb.printf("\n");
};


exports.available = available;
exports.availableJson = availableJson;
exports.installationInfo = installationInfo;
exports.getFishbowlStorage = getFishbowlStorage;
exports.info = info;
exports.search = search;
exports.searchJson = searchJson;
exports.update = update;