package q

import (
	"strings"

	"github.com/DataDog/go-sqllexer"
)

type Query interface {
	GetFullSql() string
}

func GetQueryTypeFromToken(token *sqllexer.Token) QueryType {
	if token.Type != sqllexer.COMMAND {
		return NONE
	}

	var foundType QueryType
	switch strings.ToUpper(token.Value) {
	case "SELECT":
		foundType = SELECT
	case "UPDATE":
		foundType = UPDATE
	case "INSERT":
		foundType = INSERT
	case "DELETE":
		foundType = DELETE
	default:
		foundType = NONE
	}

	return foundType
}

func IsCrudSqlStatement(token *sqllexer.Token) bool {
	queryType := GetQueryTypeFromToken(token)
	return (queryType > 0 && queryType <= 4)
}

func IsTokenBeginingOfStatement(currentToken *sqllexer.Token, previousToken *sqllexer.Token) bool {
	return IsCrudSqlStatement(currentToken)
}

func IsTokenEndOfStatement(token *sqllexer.Token) bool {
	return (token.Type == sqllexer.EOF || token.Value == ";")
}

func GetQueryTypeFromSql(sql string) QueryType {
	var queryType QueryType

	lexer := sqllexer.New(sql)
	for {
		token := lexer.Scan()
		if IsTokenEndOfStatement(token) {
			break
		}

		queryType = GetQueryTypeFromToken(token)
		if queryType > 0 {
			break
		}
	}

	return queryType
}

func ExtractSqlStatmentsFromString(sqlString string) []string {
	var foundStatments []string

	var isBeginingFound = false
	var isEndingFound = false

	var previousScannedToken sqllexer.Token
	var currentWorkingStatment = ""

	lexer := sqllexer.New(sqlString)
	for {
		token := lexer.Scan()
		previousScannedToken = *token

		if IsTokenEndOfStatement(token) {
			isEndingFound = true
		}

		if isEndingFound {
			if strings.Trim(currentWorkingStatment, " ") != "" {
				foundStatments = append(foundStatments, currentWorkingStatment)
			}

			isBeginingFound = false
			isEndingFound = false
			currentWorkingStatment = ""

			if token.Type == sqllexer.EOF {
				break
			} else {
				continue
			}
		}

		if !isBeginingFound && IsTokenBeginingOfStatement(token, &previousScannedToken) {
			isBeginingFound = true
		} else if !isBeginingFound {
			continue
		}

		currentWorkingStatment = currentWorkingStatment + token.Value
	}

	return foundStatments
}