import _ from 'lodash';

import {
  DataType,
  ModelAttributeColumnOptions,
  ModelIndexesOptions,
  QueryInterfaceOptions,
  SyncOptions,
  Transactionable,
} from 'sequelize';
import { Collection } from '../collection';
import { Database } from '../database';
import { InheritedCollection } from '../inherited-collection';
import { ModelEventTypes } from '../types';
import { snakeCase } from '../utils';

export interface FieldContext {
  database: Database;
  collection: Collection;
}

export interface BaseFieldOptions {
  name?: string;
  hidden?: boolean;

  [key: string]: any;
}

export interface BaseColumnFieldOptions extends BaseFieldOptions, Omit<ModelAttributeColumnOptions, 'type'> {
  dataType?: DataType;
  index?: boolean | ModelIndexesOptions;
}

export abstract class Field {
  options: any;
  context: FieldContext;
  database: Database;
  collection: Collection;

  [key: string]: any;

  constructor(options?: any, context?: FieldContext) {
    this.context = context as any;
    this.database = this.context.database;
    this.collection = this.context.collection;
    this.options = options || {};
    this.init();
  }

  get name() {
    return this.options.name;
  }

  get type() {
    return this.options.type;
  }

  abstract get dataType();

  async sync(syncOptions: SyncOptions) {
    await this.collection.sync({
      ...syncOptions,
      force: false,
      alter: {
        drop: false,
      },
    });
  }

  init() {
    // code
  }

  on(eventName: ModelEventTypes, listener: (...args: any[]) => void) {
    this.database.on(`${this.collection.name}.${eventName}`, listener);
    return this;
  }

  off(eventName: string, listener: (...args: any[]) => void) {
    this.database.off(`${this.collection.name}.${eventName}`, listener);
    return this;
  }

  get(name: string) {
    return this.options[name];
  }

  remove() {
    this.collection.removeIndex([this.name]);
    return this.collection.removeField(this.name);
  }

  columnName() {
    if (this.options.field) {
      return this.options.field;
    }

    if (this.database.options.underscored) {
      return snakeCase(this.name);
    }

    return this.name;
  }

  async removeFromDb(options?: QueryInterfaceOptions) {
    const attribute = this.collection.model.rawAttributes[this.name];

    if (!attribute) {
      this.remove();
      // console.log('field is not attribute');
      return;
    }

    if (this.collection.isInherited() && (<InheritedCollection>this.collection).parentFields().has(this.name)) {
      return;
    }

    if ((this.collection.model as any)._virtualAttributes.has(this.name)) {
      this.remove();
      // console.log('field is virtual attribute');
      return;
    }
    if (this.collection.model.primaryKeyAttributes.includes(this.name)) {
      // 主键不能删除
      return;
    }
    if (this.collection.model.options.timestamps !== false) {
      // timestamps 相关字段不删除
      let timestampsFields = ['createdAt', 'updatedAt', 'deletedAt'];
      if (this.database.options.underscored) {
        timestampsFields = timestampsFields.map((field) => snakeCase(field));
      }
      if (timestampsFields.includes(this.columnName())) {
        this.collection.fields.delete(this.name);
        return;
      }
    }
    // 排序字段通过 sortable 控制
    const sortable = this.collection.options.sortable;
    if (sortable) {
      let sortField: any;
      if (sortable === true) {
        sortField = 'sort';
      } else if (typeof sortable === 'string') {
        sortField = sortable;
      } else if (sortable.name) {
        sortField = sortable.name || 'sort';
      }
      if (this.name === sortField) {
        return;
      }
    }

    // if (this.options.field && this.name !== this.options.field) {
    //   // field 指向的是真实的字段名，如果与 name 不一样，说明字段只是引用
    //   this.remove();
    //   return;
    // }

    const columnReferencesCount = _.filter(
      this.collection.model.rawAttributes,
      (attr) => attr.field == this.columnName(),
    ).length;

    if (
      (await this.existsInDb({
        transaction: options?.transaction,
      })) &&
      columnReferencesCount == 1
    ) {
      const queryInterface = this.database.sequelize.getQueryInterface();
      await queryInterface.removeColumn(this.collection.getTableNameWithSchema(), this.columnName(), options);
    }

    this.remove();
  }

  async existsInDb(options?: Transactionable) {
    const opts = {
      transaction: options?.transaction,
    };
    let sql;
    if (this.database.sequelize.getDialect() === 'sqlite') {
      sql = `SELECT *
             from pragma_table_info('${this.collection.model.tableName}')
             WHERE name = '${this.columnName()}'`;
    } else if (this.database.inDialect('mysql')) {
      sql = `
        select column_name
        from INFORMATION_SCHEMA.COLUMNS
        where TABLE_SCHEMA = '${this.database.options.database}'
          AND TABLE_NAME = '${this.collection.model.tableName}'
          AND column_name = '${this.columnName()}'
      `;
    } else {
      sql = `
        select column_name
        from INFORMATION_SCHEMA.COLUMNS
        where TABLE_NAME = '${this.collection.model.tableName}'
          AND column_name = '${this.columnName()}'
          AND table_schema = '${this.collection.collectionSchema() || 'public'}'
      `;
    }
    const [rows] = await this.database.sequelize.query(sql, opts);
    return rows.length > 0;
  }

  merge(obj: any) {
    Object.assign(this.options, obj);
  }

  bind() {
    const { model } = this.context.collection;
    model.rawAttributes[this.name] = this.toSequelize();
    // @ts-ignore
    model.refreshAttributes();
    if (this.options.index) {
      this.context.collection.addIndex([this.name]);
    }
  }

  unbind() {
    const { model } = this.context.collection;
    model.removeAttribute(this.name);
    if (this.options.index || this.options.unique) {
      this.context.collection.removeIndex([this.name]);
    }
  }

  toSequelize(): any {
    const opts = _.omit(this.options, ['name']);
    if (this.dataType) {
      Object.assign(opts, { type: this.dataType });
    }
    return opts;
  }

  isSqlite() {
    return this.database.sequelize.getDialect() === 'sqlite';
  }

  typeToString() {
    return this.dataType.toString();
  }
}