module.exports = function(crowi) {
  var debug = require('debug')('crowi:models:revision')
    , mongoose = require('mongoose')
    , ObjectId = mongoose.Schema.Types.ObjectId
    , revisionSchema;

  revisionSchema = new mongoose.Schema({
    path: { type: String, required: true },
    body: { type: String, required: true },
    format: { type: String, default: 'markdown' },
    author: { type: ObjectId, ref: 'User' },
    createdAt: { type: Date, default: Date.now }
  });

  revisionSchema.statics.findLatestRevision = function(path, cb) {
    this.find({path: path})
      .sort({createdAt: -1})
      .limit(1)
      .exec(function(err, data) {
        cb(err, data.shift());
      });
  };

  revisionSchema.statics.findRevision = function(id) {
    var Revision = this;

    return new Promise(function(resolve, reject) {
      Revision.findById(id)
        .populate('author')
        .exec(function(err, data) {
          if (err) {
            return reject(err);
          }

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

  revisionSchema.statics.findRevisions = function(ids) {
    var Revision = this,
        User = crowi.model('User');

    if (!Array.isArray(ids)) {
      return Promise.reject('The argument was not Array.');
    }

    return new Promise(function(resolve, reject) {
      Revision
        .find({ _id: { $in: ids }})
        .sort({createdAt: -1})
        .populate('author', User.USER_PUBLIC_FIELDS)
        .exec(function(err, revisions) {
          if (err) {
            return reject(err);
          }

          return resolve(revisions);
        });
    });
  };

  revisionSchema.statics.findRevisionIdList = function(path) {
    return this.find({path: path})
      .select('_id author createdAt')
      .sort({createdAt: -1})
      .exec();
  };

  revisionSchema.statics.findRevisionList = function(path, options) {
    var Revision = this,
        User = crowi.model('User');

    return new Promise(function(resolve, reject) {
      Revision.find({path: path})
        .sort({createdAt: -1})
        .populate('author', User.USER_PUBLIC_FIELDS)
        .exec(function(err, data) {
          if (err) {
            return reject(err);
          }

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

  revisionSchema.statics.updateRevisionListByPath = function(path, updateData, options) {
    var Revision = this;

    return new Promise(function(resolve, reject) {
      Revision.update({path: path}, {$set: updateData}, {multi: true}, function(err, data) {
        if (err) {
          return reject(err);
        }

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

  revisionSchema.statics.prepareRevision = function(pageData, body, user, options) {
    var Revision = this;

    if (!options) {
      options = {};
    }
    var format = options.format || 'markdown';

    if (!user._id) {
      throw new Error('Error: user should have _id');
    }

    var newRevision = new Revision();
    newRevision.path = pageData.path;
    newRevision.body = body;
    newRevision.format = format;
    newRevision.author = user._id;
    newRevision.createdAt = Date.now();

    return newRevision;
  };

  revisionSchema.statics.removeRevisionsByPath = function(path) {
    var Revision = this;

    return new Promise(function(resolve, reject) {
      Revision.remove({path: path}, function(err, data) {
        if (err) {
          return reject(err);
        }

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

  revisionSchema.statics.updatePath = function(pathName) {
  };

  return mongoose.model('Revision', revisionSchema);
};