module.exports = function(crowi) {
  var debug = require('debug')('crowi:models:page')
    , mongoose = require('mongoose')
    , ObjectId = mongoose.Schema.Types.ObjectId
    , GRANT_PUBLIC = 1
    , GRANT_RESTRICTED = 2
    , GRANT_SPECIFIED = 3
    , GRANT_OWNER = 4
    , PAGE_GRANT_ERROR = 1
    , USER_PUBLIC_FIELDS = '_id fbId image googleId name username email status createdAt' // TODO: どこか別の場所へ...
    , pageSchema;

  function populatePageData(pageData, revisionId) {
    var Page = crowi.model('Page');

    pageData.latestRevision = pageData.revision;
    if (revisionId) {
      pageData.revision = revisionId;
    }
    pageData.likerCount = pageData.liker.length || 0;
    pageData.seenUsersCount = pageData.seenUsers.length || 0;

    return new Promise(function(resolve, reject) {
      pageData.populate([
        {path: 'creator', model: 'User', select: USER_PUBLIC_FIELDS},
        {path: 'revision', model: 'Revision'},
        //{path: 'liker', options: { limit: 11 }},
        //{path: 'seenUsers', options: { limit: 11 }},
      ], function (err, pageData) {
        Page.populate(pageData, {path: 'revision.author', model: 'User', select: USER_PUBLIC_FIELDS}, function(err, data) {
          if (err) {
            return reject(err);
          }

          return resolve(data);
        });
      });
    });
  }

  pageSchema = new mongoose.Schema({
    path: { type: String, required: true, index: true },
    revision: { type: ObjectId, ref: 'Revision' },
    redirectTo: { type: String, index: true },
    grant: { type: Number, default: GRANT_PUBLIC, index: true },
    grantedUsers: [{ type: ObjectId, ref: 'User' }],
    creator: { type: ObjectId, ref: 'User', index: true },
    liker: [{ type: ObjectId, ref: 'User', index: true }],
    seenUsers: [{ type: ObjectId, ref: 'User', index: true }],
    commentCount: { type: Number, default: 0 },
    createdAt: { type: Date, default: Date.now },
    updatedAt: Date
  });

  pageSchema.methods.isPublic = function() {
    if (!this.grant || this.grant == GRANT_PUBLIC) {
      return true;
    }

    return false;
  };

  pageSchema.methods.isPortal = function() {
    if (this.path.match(/.+\/$/)) {
      return true;
    }

    return false;
  };

  pageSchema.methods.isCreator = function(userData) {
    if (this.populated('creator') && this.creator._id.toString() === userData._id.toString()) {
      return true;
    } else if (this.creator.toString() === userData._id.toString()) {
      return true
    }

    return false;
  };

  pageSchema.methods.isGrantedFor = function(userData) {
    if (this.isPublic() || this.isCreator(userData)) {
      return true;
    }

    if (this.grantedUsers.indexOf(userData._id) >= 0) {
      return true;
    }

    return false;
  };

  pageSchema.methods.isLatestRevision = function() {
    // populate されていなくて判断できない
    if (!this.latestRevision || !this.revision) {
      return true;
    }

    return (this.latestRevision == this.revision._id.toString());
  };

  pageSchema.methods.isUpdatable = function(previousRevision) {
    var revision = this.latestRevision || this.revision;
    if (revision != previousRevision) {
      return false;
    }
    return true;
  };

  pageSchema.methods.isLiked = function(userData) {
    //if (undefined === this.populated('liker')) {
    //  if (this.liker.indexOf(userData._id.toString()) != -1) {
    //    return true;
    //  }
    //  return true;
    //} else {
    return this.liker.some(function(likedUser) {
      return likedUser == userData._id.toString();
    });
    //}
  };

  pageSchema.methods.like = function(userData) {
    var self = this,
      Page = self;

    return new Promise(function(resolve, reject) {
      var added = self.liker.addToSet(userData._id);
      if (added.length > 0) {
        self.save(function(err, data) {
          if (err) {
            return reject(err);
          }
          debug('liker updated!', added);
          return resolve(data);
        });
      } else {
        debug('liker not updated');
        return reject(self);
      }
    });

  };

  pageSchema.methods.unlike = function(userData, callback) {
    var self = this,
      Page = self;

    return new Promise(function(resolve, reject) {
      var removed = self.liker.pull(userData._id);
      if (removed.length > 0) {
        self.save(function(err, data) {
          if (err) {
            return reject(err);
          }
          debug('unlike updated!', removed);
          return resolve(data);
        });
      } else {
        debug('unlike not updated');
        return reject(self);
      }
    });

  };

  pageSchema.methods.isSeenUser = function(userData) {
    var self = this,
      Page = self;

    return this.seenUsers.some(function(seenUser) {
      return seenUser.equals(userData._id);
    });
  };

  pageSchema.methods.seen = function(userData) {
    var self = this,
      Page = self;

    if (this.isSeenUser(userData)) {
      debug('seenUsers not updated');
      return Promise.resolve(this);
    }

    return new Promise(function(resolve, reject) {
      if (!userData || !userData._id) {
        reject(new Error('User data is not valid'));
      }

      var added = self.seenUsers.addToSet(userData);
      self.save(function(err, data) {
        if (err) {
          return reject(err);
        }

        debug('seenUsers updated!', added);
        return resolve(self);
      });
    });
  };

  pageSchema.statics.updateCommentCount = function (page, num)
  {
    var self = this;

    return new Promise(function(resolve, reject) {
      self.update({_id: page}, {commentCount: num}, {}, function(err, data) {
        if (err) {
          debug('Update commentCount Error', err);
          return reject(err);
        }

        return resolve(data);
      });
    });
  };

  pageSchema.statics.hasPortalPage = function (path, user) {
    var self = this;
    return new Promise(function(resolve, reject) {
      self.findPage(path, user)
      .then(function(page) {
        resolve(page);
      }).catch(function(err) {
        resolve(null); // check only has portal page, through error
      });
    });
  };

  pageSchema.statics.getGrantLabels = function() {
    var grantLabels = {};
    grantLabels[GRANT_PUBLIC]     = '公開';
    grantLabels[GRANT_RESTRICTED] = 'リンクを知っている人のみ';
    //grantLabels[GRANT_SPECIFIED]  = '特定ユーザーのみ';
    grantLabels[GRANT_OWNER]      = '自分のみ';

    return grantLabels;
  };

  pageSchema.statics.normalizePath = function(path) {
    if (!path.match(/^\//)) {
      path = '/' + path;
    }

    return path;
  };

  pageSchema.statics.isCreatableName = function(name) {
    var forbiddenPages = [
      /\^|\$|\*|\+|\#/,
      /^\/_api\/.*/,
      /^\/\-\/.*/,
      /^\/_r\/.*/,
      /.+\/edit$/,
      /^\/(installer|register|login|logout|admin|me|files|trash|paste|comments).+/,
    ];

    var isCreatable = true;
    forbiddenPages.forEach(function(page) {
      var pageNameReg = new RegExp(page);
      if (name.match(pageNameReg)) {
        isCreatable = false;
        return ;
      }
    });

    return isCreatable;
  };

  pageSchema.statics.updateRevision = function(pageId, revisionId, cb) {
    this.update({_id: pageId}, {revision: revisionId}, {}, function(err, data) {
      cb(err, data);
    });
  };

  pageSchema.statics.findUpdatedList = function(offset, limit, cb) {
    this
      .find({})
      .sort('updatedAt', -1)
      .skip(offset)
      .limit(limit)
      .exec(function(err, data) {
        cb(err, data);
      });
  };

  pageSchema.statics.findPageById = function(id) {
    var Page = this;

    return new Promise(function(resolve, reject) {
      Page.findOne({_id: id}, function(err, pageData) {
        if (err) {
          return reject(err);
        }

        return populatePageData(pageData, null).then(resolve);
      });
    });
  };

  pageSchema.statics.findPageByIdAndGrantedUser = function(id, userData) {
    var Page = this;

    return new Promise(function(resolve, reject) {
      Page.findPageById(id)
      .then(function(pageData) {
        if (userData && !pageData.isGrantedFor(userData)) {
          return reject(new Error('Page is not granted for the user')); //PAGE_GRANT_ERROR, null);
        }

        return resolve(pageData);
      }).catch(function(err) {
        return reject(err);
      });
    });
  };

  // find page and check if granted user
  pageSchema.statics.findPage = function(path, userData, revisionId, ignoreNotFound) {
    var self = this;

    return new Promise(function(resolve, reject) {
      self.findOne({path: path}, function(err, pageData) {
        if (err) {
          return reject(err);
        }

        if (pageData === null) {
          if (ignoreNotFound) {
            return resolve(null);
          }

          var pageNotFoundError = new Error('Page Not Found')
          pageNotFoundError.name = 'Crowi:Page:NotFound';
          return reject(pageNotFoundError);
        }

        if (!pageData.isGrantedFor(userData)) {
          return reject(new Error('Page is not granted for the user')); //PAGE_GRANT_ERROR, null);
        }

        populatePageData(pageData, revisionId || null).then(resolve).catch(reject);
      });
    });
  };

  pageSchema.statics.findListByPageIds = function(ids, options) {
  };

  pageSchema.statics.findListByStartWith = function(path, userData, options) {
    var Page = this;

    if (!options) {
      options = {sort: 'updatedAt', desc: -1, offset: 0, limit: 50};
    }
    var opt = {
      sort: options.sort || 'updatedAt',
      desc: options.desc || -1,
      offset: options.offset || 0,
      limit: options.limit || 50
    };
    var sortOpt = {};
    sortOpt[opt.sort] = opt.desc;
    var queryReg = new RegExp('^' + path);
    var sliceOption = options.revisionSlice || {$slice: 1};

    return new Promise(function(resolve, reject) {
      var q = Page.find({
          path: queryReg,
          redirectTo: null,
          $or: [
            {grant: null},
            {grant: GRANT_PUBLIC},
            {grant: GRANT_RESTRICTED, grantedUsers: userData._id},
            {grant: GRANT_SPECIFIED, grantedUsers: userData._id},
            {grant: GRANT_OWNER, grantedUsers: userData._id},
          ],
        })
        .populate('revision')
        .sort(sortOpt)
        .skip(opt.offset)
        .limit(opt.limit);

      q.exec(function(err, data) {
        if (err) {
          return reject(err);
        }

        resolve(data);
      });
    });
  };

  pageSchema.statics.updatePage = function(page, updateData, cb) {
    // TODO foreach して save
    this.update({_id: page._id}, {$set: updateData}, function(err, data) {
      return cb(err, data);
    });
  };

  pageSchema.statics.updateGrant = function(page, grant, userData) {
    var self = this;

    return new Promise(function(resolve, reject) {
      self.update({_id: page._id}, {$set: {grant: grant}}, function(err, data) {
        if (err) {
          return reject(err);
        }

        if (grant == GRANT_PUBLIC) {
          page.grantedUsers = [];
        } else {
          page.grantedUsers = [];
          page.grantedUsers.push(userData._id);
        }
        page.save(function(err, data) {
          if (err) {
            return reject(err);
          }

          return resolve(data);
        });
      });
    });
  };

  // Instance method でいいのでは
  pageSchema.statics.pushToGrantedUsers = function(page, userData) {

    return new Promise(function(resolve, reject) {
      if (!page.grantedUsers || !Array.isArray(page.grantedUsers)) {
        page.grantedUsers = [];
      }
      page.grantedUsers.push(userData);
      page.save(function(err, data) {
        if (err) {
          return reject(err);
        }
        return resolve(data);
      });
    });
  };

  pageSchema.statics.pushRevision = function(pageData, newRevision, user) {

    return new Promise(function(resolve, reject) {
      newRevision.save(function(err, newRevision) {
        if (err) {
          debug('Error on saving revision', err);
          return reject(err);
        }

        debug('Successfully saved new revision', newRevision);
        pageData.revision = newRevision;
        pageData.updatedAt = Date.now();
        pageData.save(function(err, data) {
          if (err) {
            // todo: remove new revision?
            debug('Error on save page data (after push revision)', err);
            return reject(err);
          }

          resolve(data);
        });
      });
    });
  };

  pageSchema.statics.create = function(path, body, user, options) {
    var Page = this
      , Revision = crowi.model('Revision')
      , format = options.format || 'markdown'
      , grant = options.grant || GRANT_PUBLIC
      , redirectTo = options.redirectTo || null;

    return new Promise(function(resolve, reject) {
      Page.findOne({path: path}, function(err, pageData) {
        if (pageData) {
          return reject(new Error('Cannot create new page to existed path'));
        }

        var newPage = new Page();
        newPage.path = path;
        newPage.creator = user;
        newPage.createdAt = Date.now();
        newPage.updatedAt = Date.now();
        newPage.redirectTo = redirectTo;
        newPage.grant = grant;
        newPage.grantedUsers = [];
        newPage.grantedUsers.push(user);

        newPage.save(function (err, newPage) {
          if (err) {
            return reject(err);
          }

          var newRevision = Revision.prepareRevision(newPage, body, user, {format: format});
          Page.pushRevision(newPage, newRevision, user).then(function(data) {
            resolve(data);
          }).catch(function(err) {
            debug('Push Revision Error on create page', err);
            return reject(err);
          });
        });
      });
    });
  };

  pageSchema.statics.rename = function(pageData, newPageName, user, options, cb) {
    var Page = this
      , Revision = crowi.model('Revision')
      , path = pageData.path
      , createRedirectPage = options.createRedirectPage || 0
      , moveUnderTrees     = options.moveUnderTrees || 0;

    // pageData の path を変更
    this.updatePage(pageData, {updatedAt: Date.now(), path: newPageName}, function(err, data) {
      if (err) {
        return cb(err, null);
      }

      // reivisions の path を変更
      Revision.updateRevisionListByPath(path, {path: newPageName}, {}, function(err, data) {
        if (err) {
          return cb(err, null);
        }

        pageData.path = newPageName;
        if (createRedirectPage) {
          Page.create(path, 'redirect ' + newPageName, user, {redirectTo: newPageName}, function(err, data) {
            // @TODO error handling
            return cb(err, pageData);
          });
        } else {
          return cb(err, pageData);
        }
      });
    });
  };

  pageSchema.statics.getHistories = function() {
    // TODO
    return;
  };

  pageSchema.statics.GRANT_PUBLIC = GRANT_PUBLIC;
  pageSchema.statics.GRANT_RESTRICTED = GRANT_RESTRICTED;
  pageSchema.statics.GRANT_SPECIFIED = GRANT_SPECIFIED;
  pageSchema.statics.GRANT_OWNER = GRANT_OWNER;
  pageSchema.statics.PAGE_GRANT_ERROR = PAGE_GRANT_ERROR;

  return mongoose.model('Page', pageSchema);
};