package dpsapi

import (
	"github.com/auxten/postgresql-parser/pkg/sql/parser"
	"github.com/auxten/postgresql-parser/pkg/walk"
	"strings"
)

type insertClause struct {
	into string
}

type deleteClause struct {
}

type updateClause struct {
}

type selectClause struct {
	selectExpr []string
	from       string
	where      []string
	limit      int
	offset     int
}

func parseSql(sqlStr string) ([]any, error) {
	sqls := strings.Split(sqlStr, ";")

	sqlClauses := make([]any, 0)

	for _, sql := range sqls {
		stmts, err := parser.Parse(sql)
		if err != nil {
			return nil, err
		}

		trimSQL := strings.TrimSpace(sql)
		upperTrimSQL := strings.ToUpper(trimSQL)

		var clause any
		w := new(walk.AstWalker)

		if strings.HasPrefix(upperTrimSQL, "INSERT") {
			c := new(insertClause)
			clause = c
			w.Fn = insertWalkFunc(c)
		} else if strings.HasPrefix(upperTrimSQL, "DELETE") {
			c := new(deleteClause)
			clause = c
			w.Fn = deleteWalkFunc(c)
		} else if strings.HasPrefix(upperTrimSQL, "UPDATE") {
			c := new(updateClause)
			clause = c
			w.Fn = updateWalkFunc(c)
		} else if strings.HasPrefix(upperTrimSQL, "SELECT") {
			c := new(selectClause)
			clause = c
			w.Fn = selectWalkFunc(c)
		}

		_, err = w.Walk(stmts, nil)
		if err != nil {
			return nil, err
		}

		sqlClauses = append(sqlClauses, clause)
	}

	return sqlClauses, nil
}

func insertWalkFunc(clause *insertClause) func(ctx interface{}, node interface{}) (stop bool) {
	return func(ctx interface{}, node interface{}) (stop bool) {
		return false
	}
}

func deleteWalkFunc(clause *deleteClause) func(ctx interface{}, node interface{}) (stop bool) {
	return func(ctx interface{}, node interface{}) (stop bool) {
		return false
	}
}

func updateWalkFunc(clause *updateClause) func(ctx interface{}, node interface{}) (stop bool) {
	return func(ctx interface{}, node interface{}) (stop bool) {
		return false
	}
}

func selectWalkFunc(clause *selectClause) func(ctx interface{}, node interface{}) (stop bool) {
	return func(ctx interface{}, node interface{}) (stop bool) {
		return false
	}
}