'use strict';

/**
 * Module dependencies
 */

// Core
const path = require('path');

// Public node modules.
const _ = require('lodash');
const bookshelf = require('bookshelf');
const pluralize = require('pluralize');

// Local helpers.
const utils = require('./utils/');

// Strapi helpers for models.
const utilsModels = require('strapi-utils').models;

const PIVOT_PREFIX = '_pivot_';

/**
 * Bookshelf hook
 */

module.exports = function(strapi) {
  const hook = {
    /**
     * Default options
     */

    defaults: {
      defaultConnection: 'default',
      host: 'localhost'
    },

    /**
     * Initialize the hook
     */

    initialize: cb => {
      let globalName;


      // Initialize collections
      _.set(strapi, 'bookshelf.collections', {});

      // Return callback if there is no model
      if (_.isEmpty(strapi.models)) {
        return cb();
      }

      const connections = _.pickBy(strapi.config.connections, {
        connector: 'strapi-bookshelf'
      });

      const done = _.after(_.size(connections), () => {
        cb();
      });

      _.forEach(connections, (connection, connectionName) => {
        // Apply defaults
        _.defaults(connection.settings, strapi.hooks.bookshelf.defaults);

        // Create Bookshelf instance for this connection.
        const ORM = new bookshelf(strapi.connections[connectionName]);

        try {
          // Require `config/functions/bookshelf.js` file to customize connection.
          require(path.resolve(
            strapi.config.appPath,
            'config',
            'functions',
            'bookshelf.js'
          ))(ORM, strapi.connections[connectionName]);
        } catch (err) {
          // This is not an error if the file is not found.
        }

        // Load plugins
        if (_.get(connection, 'options.plugins') !== false) {
          ORM.plugin('visibility');
          ORM.plugin('pagination');
        }

        // Select models concerned by this connection
        const models = _.pickBy(strapi.models, {
          connection: connectionName
        });

        // Return callback if there is no model
        if (_.isEmpty(models)) {
          cb();

          // Break the loop.
          return false;
        }

        const loadedHook = _.after(_.size(models), () => {
          done();
        });

        // Parse every registered model.
        _.forEach(models, (definition, model) => {
          globalName = _.upperFirst(_.camelCase(definition.globalId));

          // Make sure the model has a table name.
          // If not, use the model name.
          if (_.isEmpty(definition.tableName)) {
            definition.tableName = model;
          }

          if (!_.isEmpty(definition.collectionName)) {
            return cb(
              'Attribute `collectionName` should be `tableName` in ' +
                globalName +
                ' model'
            );
          }

          // Add some informations about ORM & client connection
          definition.orm = 'bookshelf';
          definition.client = _.get(connection.settings, 'client');

          // Register the final model for Bookshelf.
          const loadedModel = _.assign(
            {
              tableName: definition.tableName,
              hasTimestamps: _.get(definition, 'options.timestamps') === true,
              idAttribute: _.get(definition, 'options.idAttribute') || 'id'
            },
            definition.options
          );

          if (_.isString(_.get(connection, 'options.pivot_prefix'))) {
            loadedModel.toJSON = function(options = {}) {
              const { shallow = false, omitPivot = false } = options;
              const attributes = this.serialize(options);

              if (!shallow) {
                const pivot = this.pivot &&
                  !omitPivot &&
                  this.pivot.attributes;

                // Remove pivot attributes with prefix.
                _.keys(pivot).forEach(
                  key => delete attributes[`${PIVOT_PREFIX}${key}`]
                );

                // Add pivot attributes without prefix.
                const pivotAttributes = _.mapKeys(
                  pivot,
                  (value, key) => `${connection.options.pivot_prefix}${key}`
                );

                return Object.assign({}, attributes, pivotAttributes);
              }

              return attributes;
            };
          }

          // Initialize the global variable with the
          // capitalized model name.
          global[globalName] = {};

          // Call this callback function after we are done parsing
          // all attributes for relationships-- see below.
          const done = _.after(_.size(definition.attributes), () => {
            try {
              // External function to map key that has been updated with `columnName`
              const mapper = (params = {}) =>
                _.mapKeys(params, (value, key) => {
                  const attr = definition.attributes[key] || {};

                  return _.isPlainObject(attr) &&
                    _.isString(attr['columnName'])
                    ? attr['columnName']
                    : key;
                });

              // Initialize lifecycle callbacks.
              loadedModel.initialize = function() {
                const lifecycle = {
                  creating: 'beforeCreate',
                  created: 'afterCreate',
                  destroying: 'beforeDestroy',
                  destroyed: 'afterDestroy',
                  updating: 'beforeUpdate',
                  updated: 'afterUpdate',
                  fetching: 'beforeFetch',
                  'fetching:collection': 'beforeFetchCollection',
                  fetched: 'afterFetch',
                  'fetched:collection': 'afterFetchCollection',
                  saving: 'beforeSave',
                  saved: 'afterSave'
                };

                _.forEach(lifecycle, (fn, key) => {
                  if (_.isFunction(strapi.models[model.toLowerCase()][fn])) {
                    this.on(key, strapi.models[model.toLowerCase()][fn]);
                  }
                });

                this.on('saving', (instance, attrs, options) => {
                  instance.attributes = mapper(instance.attributes);
                  attrs = mapper(attrs);

                  return _.isFunction(
                    strapi.models[model.toLowerCase()]['beforeSave']
                  )
                    ? strapi.models[model.toLowerCase()]['beforeSave']
                    : Promise.resolve();
                });
              };

              loadedModel.hidden = _.keys(
                _.keyBy(
                  _.filter(definition.attributes, (value, key) => {
                    if (
                      value.hasOwnProperty('columnName') &&
                      !_.isEmpty(value.columnName) &&
                      value.columnName !== key
                    ) {
                      return true;
                    }
                  }),
                  'columnName'
                )
              );

              global[globalName] = ORM.Model.extend(loadedModel);
              global[pluralize(globalName)] = ORM.Collection.extend({
                model: global[globalName]
              });

              // Expose ORM functions through the `strapi.models` object.
              strapi.models[model] = _.assign(global[globalName], strapi.models[model]);

              // Push model to strapi global variables.
              strapi.bookshelf.collections[globalName.toLowerCase()] = global[
                globalName
              ];

              // Push attributes to be aware of model schema.
              strapi.bookshelf.collections[
                globalName.toLowerCase()
              ]._attributes = definition.attributes;

              loadedHook();
            } catch (err) {
              strapi.log.error(
                'Impossible to register the `' + model + '` model.'
              );
              strapi.log.error(err);
              strapi.stop();
            }
          });

          if (_.isEmpty(definition.attributes)) {
            done();
          }

          // Add every relationships to the loaded model for Bookshelf.
          // Basic attributes don't need this-- only relations.
          _.forEach(definition.attributes, (details, name) => {
            const verbose = _.get(
              utilsModels.getNature(details, name),
              'verbose'
            ) || '';

            // Build associations key
            if (!_.isEmpty(verbose)) {
              utilsModels.defineAssociations(
                globalName,
                definition,
                details,
                name
              );
            }

            switch (verbose) {
              case 'hasOne': {
                const FK = _.findKey(
                  strapi.models[details.model].attributes,
                  details => {
                    if (
                      details.hasOwnProperty('model') &&
                      details.model === model &&
                      details.hasOwnProperty('via') &&
                      details.via === name
                    ) {
                      return details;
                    }
                  }
                );

                const globalId = _.get(
                  strapi.models,
                  `${details.model.toLowerCase()}.globalId`
                );

                loadedModel[name] = function() {
                  return this.hasOne(
                    global[globalId],
                    _.get(
                      strapi.models[details.model].attributes,
                      `${FK}.columnName`
                    ) || FK
                  );
                };
                break;
              }
              case 'hasMany': {
                const globalId = _.get(
                  strapi.models,
                  `${details.collection.toLowerCase()}.globalId`
                );
                const FKTarget = _.get(
                  strapi.models[globalId.toLowerCase()].attributes,
                  `${details.via}.columnName`
                ) || details.via;

                loadedModel[name] = function() {
                  return this.hasMany(global[globalId], FKTarget);
                };
                break;
              }
              case 'belongsTo': {
                const globalId = _.get(
                  strapi.models,
                  `${details.model.toLowerCase()}.globalId`
                );

                loadedModel[name] = function() {
                  return this.belongsTo(
                    global[globalId],
                    _.get(details, 'columnName') || name
                  );
                };
                break;
              }
              case 'belongsToMany': {
                const tableName = _.get(details, 'tableName') ||
                  _.map(
                    _.sortBy(
                      [
                        strapi.models[details.collection].attributes[
                          details.via
                        ],
                        details
                      ],
                      'collection'
                    ),
                    table => {
                      return _.snakeCase(
                        pluralize.plural(table.collection) +
                          ' ' +
                          pluralize.plural(table.via)
                      );
                    }
                  ).join('__');

                const relationship = _.clone(
                  strapi.models[details.collection].attributes[details.via]
                );

                // Force singular foreign key
                relationship.attribute = pluralize.singular(
                  relationship.collection
                );
                details.attribute = pluralize.singular(details.collection);

                // Define PK column
                details.column = utils.getPK(model, strapi.models);
                relationship.column = utils.getPK(
                  details.collection,
                  strapi.models
                );

                // Sometimes the many-to-many relationships
                // is on the same keys on the same models (ex: `friends` key in model `User`)
                if (
                  details.attribute + '_' + details.column ===
                  relationship.attribute + '_' + relationship.column
                ) {
                  relationship.attribute = pluralize.singular(details.via);
                }

                const globalId = _.get(
                  strapi.models,
                  `${details.collection.toLowerCase()}.globalId`
                );

                loadedModel[name] = function() {
                  if (
                    _.isArray(_.get(details, 'withPivot')) &&
                    !_.isEmpty(details.withPivot)
                  ) {
                    return this.belongsToMany(
                      global[globalId],
                      tableName,
                      relationship.attribute + '_' + relationship.column,
                      details.attribute + '_' + details.column
                    ).withPivot(details.withPivot);
                  }

                  return this.belongsToMany(
                    global[globalId],
                    tableName,
                    relationship.attribute + '_' + relationship.column,
                    details.attribute + '_' + details.column
                  );
                };
                break;
              }
              default: {
                break;
              }
            }

            done();
          });
        });
      });
    }
  };

  return hook;
};