vql/builder2.go

package vql

import (
	"encoding/json"
	"fmt"
	"strings"

	"github.com/tidwall/gjson"
)

type Builder2 struct {
	As     string      `json:"as"`
	Select interface{} `json:"select"`
	From   interface{} `json:"from"`
	Join   interface{} `json:"join"`
	Where  interface{} `json:"where"`
	Group  interface{} `json:"group"`
	Having interface{} `json:"having"`
	Order  interface{} `json:"order"`
}

func NewBuilder2() *Builder2 {
	return &Builder2{}
}

func (b *Builder2) Select2(selects ...interface{}) *Builder2 {
	b.Select = selects
	return b
}

func (b *Builder2) Sql() (string, error) {
	selectSql, err := toSelectSql(b.Select)
	if err != nil {
		return "", err
	}

	fromSql, err := toFromSql(b.From)
	if err != nil {
		return "", err
	}

	joinSql, err := toJoinSql(b.Join)
	if err != nil {
		return "", err
	}

	whereSql, err := toWhereSql(b.Where)
	if err != nil {
		return "", err
	}

	groupSql, err := toGroupSql(b.Group)
	if err != nil {
		return "", err
	}

	havingSql, err := toHavingSql(b.Having)
	if err != nil {
		return "", err
	}

	orderSql, err := toOrderSql(b.Order)
	if err != nil {
		return "", err
	}

	sql := fmt.Sprintf("select %s from %s ", selectSql, fromSql)
	if joinSql != "" {
		sql += fmt.Sprintf(" %s ", joinSql)
	}
	if whereSql != "" {
		sql += fmt.Sprintf(" where %s ", whereSql)
	}
	if groupSql != "" {
		sql += fmt.Sprintf(" group by %s ", groupSql)
	}
	if havingSql != "" {
		sql += fmt.Sprintf(" having %s ", havingSql)
	}
	if orderSql != "" {
		sql += fmt.Sprintf(" order by %s ", orderSql)
	}

	return sql, nil

}

func toSelectSql(selects interface{}) (string, error) {

	selectSql := ""
	if selectSql, ok := selects.(string); ok {
		return selectSql, nil
	}

	selectGjson := gjson.Parse(jsonEncode(selects))
	if selectGjson.IsArray() {
		ses := []string{}
		for _, se := range selectGjson.Array() {
			ses = append(ses, se.String())
		}
		selectSql = strings.Join(ses, ",")
	} else {
		selectSql = selectGjson.String()
	}
	return selectSql, nil
}

func toFromSql(from interface{}) (string, error) {
	fromSql := ""
	if fromSql, ok := from.(string); ok {
		return fromSql, nil
	}

	fromGjson := gjson.Parse(jsonEncode(from))
	if fromGjson.IsObject() {
		nb := NewBuilder2()
		json.Unmarshal([]byte(fromGjson.Raw), &nb)
		ns, err := nb.Sql()
		if err != nil {
			return "", err
		}
		if nb.As != "" {
			fromSql = fmt.Sprintf("( %s ) as %s", ns, nb.As)
		} else {
			fromSql = fmt.Sprintf("( %s )", ns)
		}
	} else {
		fromSql = fromGjson.String()
	}
	return fromSql, nil
}

func toJoinSql(join interface{}) (string, error) {
	if join == nil {
		return "", nil
	}
	// joinSql := ""
	if joinSql, ok := join.(string); ok {
		return joinSql, nil
	}

	joinGjson := gjson.Parse(jsonEncode(join))
	if joinGjson.IsArray() {
		js := []string{}
		for _, j := range joinGjson.Array() {
			nj, err := toJoinSql(j.Value())
			if err != nil {
				return "", err
			}
			js = append(js, nj)
		}
		return strings.Join(js, " "), nil
	} else {
		return "", fmt.Errorf("目前仅支持数组或者字符串")
	}

	// joinGjson := gjson.Parse(jsonEncode(join))
	// if joinGjson.IsArray() {
	// 	js := []string{}
	// 	for _, j := range joinGjson.Array() {
	// 		if j.IsObject() {
	// 			return
	// 		} else {
	// 			js = append(js, j.String())
	// 		}
	// 	}
	// 	joinSql = strings.Join(js, " ")
	// } else {
	// 	joinSql = joinGjson.String()
	// }
	// return joinSql
}

func toWhereSql(where interface{}) (string, error) {
	if where == nil {
		return "", nil
	}
	whereSql := ""
	if whereSql, ok := where.(string); ok {
		return whereSql, nil
	}

	whereGjson := gjson.Parse(jsonEncode(where))

	//[ "a=","1","and",[["c=","3"],"and",["d=","4"]],"or",["b=","2"]]
	if whereGjson.IsArray() {
		ws := []string{}
		expression := whereGjson.Array()

		if len(expression) == 0 {
			return "", nil
		}

		if expression[0].String() == "and" || expression[0].String() == "or" {

			operator := "and"

			for _, w := range expression {
				if w.Type == gjson.String {
					if whereSql == "" && (w.String() == "and" || w.String() == "or") {
						operator = w.String()
					} else {
						ws = append(ws, w.String())
					}
				} else {
					newExp, err := toWhereSql(w.Value())
					if err != nil {
						return "", err
					}
					ws = append(ws, newExp)
				}

				whereSql = strings.Join(ws, fmt.Sprintf(" %s ", operator))
			}
		} else {
			for _, w := range expression {
				if w.Type == gjson.String {
					ws = append(ws, w.String())
				} else {
					newExp, err := toWhereSql(w.Value())
					if err != nil {
						return "", err
					}
					ws = append(ws, newExp)
				}

				whereSql = strings.Join(ws, " ")
			}
		}
	} else if whereGjson.IsObject() {
		newValue := []interface{}{
			"and",
		}

		ops := []string{"=", ">", ">=", "<", "<=", "<>", "!="}

		for k, v := range whereGjson.Map() {
			if v.Value() == nil {
				continue
			}

			prefix := k
			mop := "="

			for _, op := range ops {
				if strings.HasSuffix(k, op) {
					prefix = strings.TrimSuffix(k, op)
					mop = op
					break
				}
			}

			newValue = append(newValue, []string{prefix, mop, v.String()})
		}

		return toWhereSql(newValue)
	} else {
		whereSql = whereGjson.String()
	}
	return fmt.Sprintf("( %s )", whereSql), nil
}

func toGroupSql(group interface{}) (string, error) {
	if group == nil {
		return "", nil
	}
	// groupSql := ""
	if groupSql, ok := group.(string); ok {
		return groupSql, nil
	}
	return "", fmt.Errorf("暂时不支持非字符串类型的group语句")
}

func toHavingSql(having interface{}) (string, error) {
	if having == nil {
		return "", nil
	}
	// havingSql := ""
	if havingSql, ok := having.(string); ok {
		return havingSql, nil
	}
	return "", fmt.Errorf("暂时不支持非字符串类型的having语句")
}

func toOrderSql(order interface{}) (string, error) {
	if order == nil {
		return "", nil
	}
	// orderSql := ""
	if orderSql, ok := order.(string); ok {
		return orderSql, nil
	}
	return "", fmt.Errorf("暂时不支持非字符串类型的order语句")
}