import {isEmpty, isString, isNumber, isBoolean, assert, reverseMerge} from "./utils"
import request from "./utils/request"
import Condition from './condition'
import AssociativeCondition from "./associativeCondition"

export default class QueryBuilder {
 table;
 conditions = [];
 queryType = 2; // 1表示返回总数, 2表示返回列表数和总数
 multiple = false;
 resField;
 pagination;
 orders;
 associativeCondition = [];

 static by(table, queryType) {
 return new QueryBuilder(table, queryType)
 }

 constructor(table, queryType) {
 assert(!isEmpty(table) && isString(table), `[ApiJson] 参数table: ${table} 非法`)
 if (queryType !== undefined) {
 assert([1, 2].indexOf(queryType) > -1, `[ApiJson] 参数queryType: ${queryType} 非法, 必须为数值1或2`)
 this.queryType = queryType
 }
 this.table = table
 }

 /**
 * 设置关联条件
 * @param table 关联的主表表名
 * @param primaryKey 关联的主表主键
 * @param foreignKey 和主表关联的当前表的外键。可以只输入字段名,或者符合apijson的外键全路径(以/开头)
 * @param resField 关联的主表响应字段
 */
 setAssociativeCondition(table, primaryKey, foreignKey, resField) {
 if (!isEmpty(foreignKey) && !foreignKey.startsWith("/")) {
 foreignKey = "/" + this.table + "/" + foreignKey
 }
 this.associativeCondition.push(AssociativeCondition.by(table, primaryKey, foreignKey, resField))
 return this
 }

 /**
 * 设置关联条件
 * @param condition
 * @returns {QueryBuilder}
 */
 setAssociativeConditionPlus(condition) {
 assert(condition instanceof AssociativeCondition, `[ApiJson] 参数condition: ${condition} 非法, 必须是 AssociativeCondition类型`)
 this.associativeCondition.push(condition)
 return this
 }

 condition(condition) {
 assert(condition instanceof Condition, `[ApiJson] 参数condition: ${condition} 非法, 必须是 Condition类型`)
 this.conditions.push(condition)
 return this;
 }

 setResFields(fields = '*') {
 assert(!isEmpty(fields) && isString(fields), `[ApiJson] 参数fields: ${fields} 非法`)

 if (fields.trim() !== '*') {
 this.resField = fields;
 }
 return this;
 }

 multi(multi = false) {
 this.multiple = multi;
 return this;
 }

 page(page = 0, count = 10) {
 assert(isNumber(page) && isNumber(count), `[ApiJson] 参数page: ${page} 和 count: ${count} 都必须为Number类型`)
 this.pagination = {
 page: page,
 count: count
 }
 return this;
 }

 /**
 *
 * @param field
 * @param desc 是否降序, 默认true
 */
 order(field, desc = true) {
 assert(!isEmpty(field) && isString(field), `[ApiJson] 参数field: ${field} 非法`)
 assert(isBoolean(desc), `[ApiJson] 参数desc: ${desc} 非法`)

 this.orders = {};
 this.orders[field] = (desc ? '-' : '+ ');
 return this;
 }

 toJson() {
 let json = {};
 const {table, conditions, pagination, resField, orders, multiple, associativeCondition, queryType} = this;

 assert(!(pagination && multiple === false), '指定了分页内容, 则必须指定multiple为true!')

 function tableToJson(table, conditions, resField, orders) {
 const tableJson = {};
 if (conditions && conditions.length > 0) {
 conditions.forEach(c => {
 const json = c.toJson()
 if (json !== null) {
 reverseMerge(tableJson, c.toJson())
 }
 });
 }
 if (resField) {
 tableJson['@column'] = resField + ',id'; // id内置
 }
 if (orders) {
 tableJson['@order'] = Object.keys(orders).map(field => field + orders[field]).join(',');
 }
 const json = {}
 json[table] = tableJson;
 return json;
 }

 function associativeTableToJson(associativeCondition, json) {
 associativeCondition.forEach(c => {
 reverseMerge(json, c.toJson())
 })
 }

 if (multiple) {
 json['[]'] = tableToJson(table, conditions, resField, orders)
 associativeTableToJson(associativeCondition, json['[]'])
 if (pagination) {
 reverseMerge(json['[]'], pagination)
 }

 json['[]']['query'] = queryType; // 查询数据和总数(附带total表示总数) // https://vincentcheng.github.io/apijson-doc/zh/grammar.html#%E5%88%86%E9%A1%B5
 json['total@'] = '/[]/total'
 } else {
 json = tableToJson(table, conditions, resField, orders)
 associativeTableToJson(associativeCondition, json)
 }

 return json
 }

 send() {
 const params = this.toJson();
 return request({
 url: '/get',
 method: 'post',
 data: params
 })
 }
}