const Bluebird = require('bluebird');

const Raw = require('./raw');
const Ref = require('./ref');
const Runner = require('./runner');
const Formatter = require('./formatter');
const Transaction = require('./transaction');

const QueryBuilder = require('./query/builder');
const QueryCompiler = require('./query/compiler');

const SchemaBuilder = require('./schema/builder');
const SchemaCompiler = require('./schema/compiler');
const TableBuilder = require('./schema/tablebuilder');
const TableCompiler = require('./schema/tablecompiler');
const ColumnBuilder = require('./schema/columnbuilder');
const ColumnCompiler = require('./schema/columncompiler');

const { Pool, TimeoutError } = require('tarn');
const inherits = require('inherits');
const { EventEmitter } = require('events');
const { promisify } = require('util');

const { makeEscape } = require('./query/string');
const { uniqueId, cloneDeep, defaults } = require('lodash');

const Logger = require('./logger');

const debug = require('debug')('knex:client');
const _debugQuery = require('debug')('knex:query');
const debugBindings = require('debug')('knex:bindings');

const debugQuery = (sql, txId) => _debugQuery(sql.replace(/%/g, '%%'), txId);

const { POOL_CONFIG_OPTIONS } = require('./constants');

// The base client provides the general structure
// for a dialect specific client object.
function Client(config = {}) {
  this.config = config;
  this.logger = new Logger(config);

  //Client is a required field, so throw error if it's not supplied.
  //If 'this.dialect' is set, then this is a 'super()' call, in which case
  //'client' does not have to be set as it's already assigned on the client prototype.

  if (this.dialect && !this.config.client) {
    this.logger.warn(
      `Using 'this.dialect' to identify the client is deprecated and support for it will be removed in the future. Please use configuration option 'client' instead.`
    );
  }
  const dbClient = this.config.client || this.dialect;
  if (!dbClient) {
    throw new Error(`knex: Required configuration option 'client' is missing.`);
  }

  if (config.version) {
    this.version = config.version;
  }

  if (config.connection && config.connection instanceof Function) {
    this.connectionConfigProvider = config.connection;
    this.connectionConfigExpirationChecker = () => true; // causes the provider to be called on first use
  } else {
    this.connectionSettings = cloneDeep(config.connection || {});
    this.connectionConfigExpirationChecker = null;
  }
  if (this.driverName && config.connection) {
    this.initializeDriver();
    if (!config.pool || (config.pool && config.pool.max !== 0)) {
      this.initializePool(config);
    }
  }
  this.valueForUndefined = this.raw('DEFAULT');
  if (config.useNullAsDefault) {
    this.valueForUndefined = null;
  }
}

inherits(Client, EventEmitter);

Object.assign(Client.prototype, {
  formatter(builder) {
    return new Formatter(this, builder);
  },

  queryBuilder() {
    return new QueryBuilder(this);
  },

  queryCompiler(builder) {
    return new QueryCompiler(this, builder);
  },

  schemaBuilder() {
    return new SchemaBuilder(this);
  },

  schemaCompiler(builder) {
    return new SchemaCompiler(this, builder);
  },

  tableBuilder(type, tableName, fn) {
    return new TableBuilder(this, type, tableName, fn);
  },

  tableCompiler(tableBuilder) {
    return new TableCompiler(this, tableBuilder);
  },

  columnBuilder(tableBuilder, type, args) {
    return new ColumnBuilder(this, tableBuilder, type, args);
  },

  columnCompiler(tableBuilder, columnBuilder) {
    return new ColumnCompiler(this, tableBuilder, columnBuilder);
  },

  runner(builder) {
    return new Runner(this, builder);
  },

  transaction(container, config, outerTx) {
    return new Transaction(this, container, config, outerTx);
  },

  raw() {
    return new Raw(this).set(...arguments);
  },

  ref() {
    return new Ref(this, ...arguments);
  },

  _formatQuery(sql, bindings, timeZone) {
    bindings = bindings == null ? [] : [].concat(bindings);
    let index = 0;
    return sql.replace(/\\?\?/g, (match) => {
      if (match === '\\?') {
        return '?';
      }
      if (index === bindings.length) {
        return match;
      }
      const value = bindings[index++];
      return this._escapeBinding(value, { timeZone });
    });
  },

  _escapeBinding: makeEscape({
    escapeString(str) {
      return `'${str.replace(/'/g, "''")}'`;
    },
  }),

  query(connection, obj) {
    if (typeof obj === 'string') obj = { sql: obj };
    obj.bindings = this.prepBindings(obj.bindings);

    const { __knexUid, __knexTxId } = connection;

    this.emit('query', Object.assign({ __knexUid, __knexTxId }, obj));
    debugQuery(obj.sql, __knexTxId);
    debugBindings(obj.bindings, __knexTxId);

    obj.sql = this.positionBindings(obj.sql);

    return this._query(connection, obj).catch((err) => {
      err.message =
        this._formatQuery(obj.sql, obj.bindings) + ' - ' + err.message;
      this.emit(
        'query-error',
        err,
        Object.assign({ __knexUid, __knexTxId }, obj)
      );
      throw err;
    });
  },

  stream(connection, obj, stream, options) {
    if (typeof obj === 'string') obj = { sql: obj };
    obj.bindings = this.prepBindings(obj.bindings);

    const { __knexUid, __knexTxId } = connection;

    this.emit('query', Object.assign({ __knexUid, __knexTxId }, obj));
    debugQuery(obj.sql, __knexTxId);
    debugBindings(obj.bindings, __knexTxId);

    obj.sql = this.positionBindings(obj.sql);

    return this._stream(connection, obj, stream, options);
  },

  prepBindings(bindings) {
    return bindings;
  },

  positionBindings(sql) {
    return sql;
  },

  postProcessResponse(resp, queryContext) {
    if (this.config.postProcessResponse) {
      return this.config.postProcessResponse(resp, queryContext);
    }
    return resp;
  },

  wrapIdentifier(value, queryContext) {
    return this.customWrapIdentifier(
      value,
      this.wrapIdentifierImpl,
      queryContext
    );
  },

  customWrapIdentifier(value, origImpl, queryContext) {
    if (this.config.wrapIdentifier) {
      return this.config.wrapIdentifier(value, origImpl, queryContext);
    }
    return origImpl(value);
  },

  wrapIdentifierImpl(value) {
    return value !== '*' ? `"${value.replace(/"/g, '""')}"` : '*';
  },

  initializeDriver() {
    try {
      this.driver = this._driver();
    } catch (e) {
      const message = `Knex: run\n$ npm install ${this.driverName} --save`;
      this.logger.error(`${message}\n${e.message}\n${e.stack}`);
      throw new Error(`${message}\n${e.message}`);
    }
  },

  poolDefaults() {
    return { min: 2, max: 10, propagateCreateError: true };
  },

  getPoolSettings(poolConfig) {
    poolConfig = defaults({}, poolConfig, this.poolDefaults());

    POOL_CONFIG_OPTIONS.forEach((option) => {
      if (option in poolConfig) {
        this.logger.warn(
          [
            `Pool config option "${option}" is no longer supported.`,
            `See https://github.com/Vincit/tarn.js for possible pool config options.`,
          ].join(' ')
        );
      }
    });

    const timeouts = [
      this.config.acquireConnectionTimeout || 60000,
      poolConfig.acquireTimeoutMillis,
    ].filter((timeout) => timeout !== undefined);

    // acquire connection timeout can be set on config or config.pool
    // choose the smallest, positive timeout setting and set on poolConfig
    poolConfig.acquireTimeoutMillis = Math.min(...timeouts);

    const updatePoolConnectionSettingsFromProvider = async () => {
      if (!this.connectionConfigProvider) {
        return; // static configuration, nothing to update
      }
      if (
        !this.connectionConfigExpirationChecker ||
        !this.connectionConfigExpirationChecker()
      ) {
        return; // not expired, reuse existing connection
      }
      const providerResult = await this.connectionConfigProvider();
      if (providerResult.expirationChecker) {
        this.connectionConfigExpirationChecker =
          providerResult.expirationChecker;
        delete providerResult.expirationChecker; // MySQL2 driver warns on receiving extra properties
      } else {
        this.connectionConfigExpirationChecker = null;
      }
      this.connectionSettings = providerResult;
    };

    return Object.assign(poolConfig, {
      create: async () => {
        await updatePoolConnectionSettingsFromProvider();
        const connection = await this.acquireRawConnection();
        connection.__knexUid = uniqueId('__knexUid');
        if (poolConfig.afterCreate) {
          await promisify(poolConfig.afterCreate)(connection);
        }
        return connection;
      },

      destroy: (connection) => {
        if (connection !== void 0) {
          return this.destroyRawConnection(connection);
        }
      },

      validate: (connection) => {
        if (connection.__knex__disposed) {
          this.logger.warn(`Connection Error: ${connection.__knex__disposed}`);
          return false;
        }

        return this.validateConnection(connection);
      },
    });
  },

  initializePool(config = this.config) {
    if (this.pool) {
      this.logger.warn('The pool has already been initialized');
      return;
    }

    const tarnPoolConfig = {
      ...this.getPoolSettings(config.pool),
    };
    // afterCreate is an internal knex param, tarn.js does not support it
    if (tarnPoolConfig.afterCreate) {
      delete tarnPoolConfig.afterCreate;
    }

    this.pool = new Pool(tarnPoolConfig);
  },

  validateConnection(connection) {
    return true;
  },

  // Acquire a connection from the pool.
  acquireConnection() {
    if (!this.pool) {
      return Bluebird.reject(new Error('Unable to acquire a connection'));
    }
    try {
      return Bluebird.try(() => this.pool.acquire().promise)
        .then((connection) => {
          debug('acquired connection from pool: %s', connection.__knexUid);
          return connection;
        })
        .catch(TimeoutError, () => {
          throw new Bluebird.TimeoutError(
            'Knex: Timeout acquiring a connection. The pool is probably full. ' +
              'Are you missing a .transacting(trx) call?'
          );
        });
    } catch (e) {
      return Bluebird.reject(e);
    }
  },

  // Releases a connection back to the connection pool,
  // returning a promise resolved when the connection is released.
  releaseConnection(connection) {
    debug('releasing connection to pool: %s', connection.__knexUid);
    const didRelease = this.pool.release(connection);

    if (!didRelease) {
      debug('pool refused connection: %s', connection.__knexUid);
    }

    return Bluebird.resolve();
  },

  // Destroy the current connection pool for the client.
  destroy(callback) {
    const maybeDestroy = this.pool && this.pool.destroy();

    return Bluebird.resolve(maybeDestroy)
      .then(() => {
        this.pool = void 0;

        if (typeof callback === 'function') {
          callback();
        }
      })
      .catch((err) => {
        if (typeof callback === 'function') {
          callback(err);
        }

        return Bluebird.reject(err);
      });
  },

  // Return the database being used by this client.
  database() {
    return this.connectionSettings.database;
  },

  toString() {
    return '[object KnexClient]';
  },

  canCancelQuery: false,

  assertCanCancelQuery() {
    if (!this.canCancelQuery) {
      throw new Error('Query cancelling not supported for this dialect');
    }
  },

  cancelQuery() {
    throw new Error('Query cancelling not supported for this dialect');
  },
});

module.exports = Client;