package vql

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

	"git.ouxuan.net/3136352472/vql/builder"
	"github.com/spf13/cast"
	"github.com/xwb1989/sqlparser"
)

type CondType string

const (
	CondTypeCondition CondType = "condition"
	CondTypeAnd       CondType = "and"
	CondTypeOr        CondType = "or"
)

type FieldValue struct {
	Type  string `json:"type"` // field, value
	Field *Field `json:"field,omitempty"`
	Value string `json:"value,omitempty"`
}

type WhereCondition struct {
	Condition string     `json:"condition"`
	Left      FieldValue `json:"left"`
	Right     FieldValue `json:"right"`
}

type Where struct {
	Cond  CondType        `json:"cond"`
	Sub   []Where         `json:"sub,omitempty"`
	Value *WhereCondition `json:"value,omitempty"`
}

func (w *Where) ToCond() (builder.Cond, error) {
	var cond builder.Cond
	if w.Cond != CondTypeCondition {
		var conds []builder.Cond
		for _, v := range w.Sub {
			subCond, err := v.ToCond()
			if err != nil {
				return nil, err
			}
			conds = append(conds, subCond)
		}

		switch w.Cond {
		case CondTypeAnd:
			cond = builder.And(conds...)
		case CondTypeOr:
			cond = builder.Or(conds...)
		}
	} else {

		l := ""
		if w.Value.Left.Type == "field" {
			l = w.Value.Left.Field.Name
			if w.Value.Left.Field.FromTable != "" {
				l = fmt.Sprint(w.Value.Left.Field.FromTable, ".", l)
			}
		} else {
			l = w.Value.Left.Value
		}
		var r interface{}
		if w.Value.Right.Type == "field" {
			r = w.Value.Right.Field.Name
			if w.Value.Right.Field.FromTable != "" {
				r = builder.Field(fmt.Sprint(w.Value.Right.Field.FromTable, ".", r))
			}
		} else {
			r = w.Value.Right.Value
		}
		switch w.Value.Condition {
		case "eq", "equal", "=":

			cond = builder.Eq{l: r}
		case "neq", "not equal", "!=":
			cond = builder.Neq{l: r}
		case "gt", "greater than", ">":
			cond = builder.Gt{l: r}
		case "gte", "greater than or equal", ">=":
			cond = builder.Gte{l: r}
		case "lt", "less than", "<":
			cond = builder.Lt{l: r}
		case "lte", "less than or equal", "<=":
			cond = builder.Lte{l: r}
		case "like":
			cond = builder.Like{l, fmt.Sprint(r)}
		case "not like":
			cond = builder.Like{fmt.Sprint(l, " not"), fmt.Sprint(r)}
		case "in":
			cond = builder.In(l, r)
		case "not in":
			cond = builder.NotIn(l, r)
		default:
			return nil, fmt.Errorf("unknown condition: %s", w.Value.Condition)
		}
	}

	return cond, nil
}

func (w *Where) FromSql(sql string) error {
	stmt, err := sqlparser.Parse(sql)
	if err != nil {
		return err
	}

	switch stmt.(type) {
	case *sqlparser.Select:
		sel := stmt.(*sqlparser.Select)
		if sel.Where != nil {
			return w.fromExpr(sel.Where.Expr)
		}
	}
	return nil
}
func (w *Where) fromExpr(expr sqlparser.Expr) error {

	// log.Println("expr:", reflect.TypeOf(expr), jsonEncode(expr))
	switch expr.(type) {
	case *sqlparser.AndExpr:
		var left, right Where
		w.Cond = CondTypeAnd
		and := expr.(*sqlparser.AndExpr)
		if err := left.fromExpr(and.Left); err != nil {
			return err
		}
		w.Sub = append(w.Sub, left)

		if err := right.fromExpr(and.Right); err != nil {
			return err
		}
		w.Sub = append(w.Sub, right)
	case *sqlparser.OrExpr:
		var left, right Where
		w.Cond = CondTypeOr
		or := expr.(*sqlparser.OrExpr)

		if err := left.fromExpr(or.Left); err != nil {
			return err
		}
		w.Sub = append(w.Sub, left)
		if err := right.fromExpr(or.Right); err != nil {
			return err
		}
		w.Sub = append(w.Sub, right)
	case *sqlparser.ParenExpr:
		paren := expr.(*sqlparser.ParenExpr)
		if err := w.fromExpr(paren.Expr); err != nil {
			return err
		}
	case *sqlparser.ComparisonExpr:
		w.Cond = CondTypeCondition
		return w.conditionExpr(expr)
	default:
		return fmt.Errorf("unknown expr: %s", reflect.TypeOf(expr))
		log.Println("unknown expr:", reflect.TypeOf(expr), jsonEncode(expr))
	}
	return nil
}

func (w *Where) conditionExpr(expr sqlparser.Expr) error {
	// log.Println("conditionExpr:", reflect.TypeOf(expr), jsonEncode(expr))
	switch expr.(type) {
	case *sqlparser.ComparisonExpr:
		comp := expr.(*sqlparser.ComparisonExpr)
		w.Value = &WhereCondition{}

		w.Value.Condition = "unknown"
		switch comp.Operator {
		case "=":
			w.Value.Condition = "eq"
		case "!=":
			w.Value.Condition = "neq"
		case ">":
			w.Value.Condition = "gt"
		case ">=":
			w.Value.Condition = "gte"
		case "<":
			w.Value.Condition = "lt"
		case "<=":
			w.Value.Condition = "lte"
		case "like":
			w.Value.Condition = "like"
		case "not like":
			w.Value.Condition = "not like"
		case "in":
			w.Value.Condition = "in"
		case "not in":
			w.Value.Condition = "not in"
		default:
			return fmt.Errorf("unknown operator: %s", comp.Operator)
		}

		if leftCol, ok := comp.Left.(*sqlparser.ColName); ok {
			w.Value.Left = FieldValue{
				Type: "field",
				Field: &Field{
					Name:      string(leftCol.Name.String()),
					FromTable: string(leftCol.Qualifier.Name.String()),
				},
			}

		} else if leftVal, ok := comp.Left.(*sqlparser.SQLVal); ok {
			w.Value.Left = FieldValue{
				Type:  "value",
				Value: string(leftVal.Val),
			}
		} else {
			return fmt.Errorf("unexpected left type: %T", comp.Left)
		}

		if rightCol, ok := comp.Right.(*sqlparser.ColName); ok {
			w.Value.Right = FieldValue{
				Type: "field",
				Field: &Field{
					Name:      string(rightCol.Name.String()),
					FromTable: string(rightCol.Qualifier.Name.String()),
				},
			}
		} else if rightVal, ok := comp.Right.(*sqlparser.SQLVal); ok {
			w.Value.Right = FieldValue{
				Type:  "value",
				Value: string(rightVal.Val),
			}
		} else {
			return fmt.Errorf("unexpected right type: %T", comp.Right)
		}
	default:
		return fmt.Errorf("unexpected type: %T", expr)
	}
	// log.Println("Where:", w)
	return nil
}

func (w *Where) FromCond(cond builder.Cond) error {
	if cond == nil {
		return fmt.Errorf("condition is nil")
	}

	switch builder.CondType(cond) {
	case "and":
		w.Cond = CondTypeAnd
		condAnd := builder.GetCondAnd(cond)
		for _, v := range condAnd {
			var sub Where
			sub.FromCond(v)
			w.Sub = append(w.Sub, sub)
		}
	case "or":
		w.Cond = CondTypeOr
		condOr := builder.GetCondOr(cond)
		for _, v := range condOr {
			var sub Where
			sub.FromCond(v)
			w.Sub = append(w.Sub, sub)
		}
	default:
		w.Cond = "condition"
		err := w.condition(cond)
		if err != nil {
			return err
		}
	}
	return nil
}

func (w *Where) condition(cond builder.Cond) error {
	condMap := map[string]interface{}{}
	json.Unmarshal([]byte(jsonEncode(cond)), &condMap)
	conditionName := ""
	switch cond.(type) {
	case builder.Eq:
		conditionName = "eq"
	case builder.Neq:
		conditionName = "neq"
	case builder.Gt:
		conditionName = "gt"
	case builder.Gte:
		conditionName = "gte"
	case builder.Lt:
		conditionName = "lt"
	case builder.Lte:
		conditionName = "lte"
	case builder.Like:
		conditionName = "like"
	case builder.Between:
		conditionName = "between"
	default:
		ct := builder.CondType(cond)
		if ct == "in" {
			conditionName = "in"
		} else if ct == "not in" {
			conditionName = "not in"
		} else {
			return fmt.Errorf("condition type %s not support", ct)
		}
	}
	if len(condMap) > 1 {
		w.Cond = CondTypeCondition
		for k, v := range condMap {
			var sub Where
			sub.Value = &WhereCondition{
				Condition: conditionName,
				Left: FieldValue{
					Type:  "value",
					Value: k,
				},
				Right: FieldValue{
					Type:  "value",
					Value: fmt.Sprint(v),
				},
			}
			w.Sub = append(w.Sub, sub)
		}
	} else {
		w.Value = &WhereCondition{
			Condition: conditionName,
		}
		for k, v := range condMap {
			w.Value.Left = FieldValue{
				Type:  "value",
				Value: k,
			}
			w.Value.Right = FieldValue{
				Type:  "value",
				Value: fmt.Sprint(v),
			}
		}
	}
	return nil
}

type Field struct {
	FromTable string `json:"from_table"`
	Name      string `json:"name"`
	As        string `json:"as"`
}

type From struct {
	Table    string `json:"table"`
	SubQuery *Query `json:"sub_query,omitempty"`
	raw      string `json:"-"`
	As       string `json:"as"`
}

type Join struct {
	Type      string `json:"type"`
	Query     *Query `json:"query"`
	JoinWhere *Where `json:"join_where,omitempty"`
}

type Limit struct {
	Offset int `json:"offset"`
	Count  int `json:"count"`
}
type OrderByField struct {
	Field     Field  `json:"field"`
	Direction string `json:"desc"`
}
type Query struct {
	Dialect DialectType    `json:"dialect"`
	From    From           `json:"from"`
	Join    []Join         `json:"join,omitempty"`
	Fields  []Field        `json:"field,omitempty"`
	Where   *Where         `json:"where,omitempty"`
	GroupBy []Field        `json:"group_by,omitempty"`
	Having  string         `json:"having,omitempty"`
	OrderBy []OrderByField `json:"order_by,omitempty"`
	Limit   *Limit         `json:"limit,omitempty"`
}

func getTheLeftmost(node *sqlparser.JoinTableExpr) (left *sqlparser.AliasedTableExpr) {
	if node.LeftExpr == nil {
		return nil
	}
	switch left := node.LeftExpr.(type) {
	case *sqlparser.AliasedTableExpr:
		return left
	case *sqlparser.JoinTableExpr:
		return getTheLeftmost(left)
	default:
		return nil
	}
}

func nodeExtractRawSQL(node sqlparser.SQLNode) string {
	buff := sqlparser.NewTrackedBuffer(nil)
	node.Format(buff)
	return buff.String()
}

func (q *Query) FromSelect(selectStmt *sqlparser.Select) error {
	if selectStmt == nil {
		return fmt.Errorf("selectStmt is nil")
	}

	if selectStmt.SelectExprs != nil {
		for _, v := range selectStmt.SelectExprs {
			switch expr := v.(type) {
			case *sqlparser.StarExpr:
				// log.Println("selectStmt.StarExpr", reflect.TypeOf(expr), jsonEncode(expr))
				q.Fields = append(q.Fields, Field{
					Name:      "*",
					FromTable: expr.TableName.Name.String(),
				})
			case *sqlparser.AliasedExpr:
				// log.Println("selectStmt.AliasedExpr", reflect.TypeOf(expr.Expr), jsonEncode(expr.Expr))
				switch colName := expr.Expr.(type) {
				case *sqlparser.ColName:
					q.Fields = append(q.Fields, Field{
						FromTable: colName.Qualifier.Name.String(),
						Name:      string(colName.Name.String()),
						As:        expr.As.String(),
					})
				case *sqlparser.FuncExpr:
					name := nodeExtractRawSQL(colName)
					q.Fields = append(q.Fields, Field{
						Name: name,
						As:   expr.As.String(),
					})
				}
			}
		}
	}

	if selectStmt.Where != nil {
		if q.Where == nil {
			q.Where = &Where{}
		}
		if err := q.Where.fromExpr(selectStmt.Where.Expr); err != nil {
			return err
		}
	}

	if selectStmt.From != nil {
		if len(selectStmt.From) > 1 {
			return fmt.Errorf("not support multi table")
		}
		form := selectStmt.From[0]

		switch form := form.(type) {
		case *sqlparser.AliasedTableExpr: //未联表
			if form.As.String() != "" {
				q.From.As = form.As.String()
			}
			switch exp := form.Expr.(type) {
			case sqlparser.TableName:
				// log.Println("TableName:", jsonEncode(exp))
				q.From.Table = string(exp.Name.String())

			case *sqlparser.Subquery:
				subQuery := &Query{}
				if err := subQuery.FromSelect(exp.Select.(*sqlparser.Select)); err != nil {
					return err
				}
				q.From.SubQuery = subQuery
			}
		case *sqlparser.JoinTableExpr: //有联表
			// log.Println("JoinTableExpr:", jsonEncode(form))

			//确定主表
			leftmost := getTheLeftmost(form)
			if leftmost != nil {
				// log.Println("leftmost:", jsonEncode(leftmost))
				if leftmost.As.String() != "" {
					q.From.As = leftmost.As.String()
				}
				switch leftmostExpr := leftmost.Expr.(type) {
				case sqlparser.TableName:
					q.From.Table = string(leftmostExpr.Name.String())
				case *sqlparser.Subquery:
					subQuery := &Query{}
					if err := subQuery.FromSelect(leftmostExpr.Select.(*sqlparser.Select)); err != nil {
						return err
					}
					q.From.SubQuery = subQuery
				}

			} else {
				//找不到最左边的表
				return fmt.Errorf("can not find the leftmost table")
			}

			//确定联表
			for {
				if form == nil {
					break
				}
				join := Join{
					Type: strings.ToUpper(strings.Trim(strings.TrimSuffix(strings.Trim(strings.ToLower(form.Join), " "), "join"), " ")),
				}

				switch right := form.RightExpr.(type) {
				case *sqlparser.AliasedTableExpr:
					join.Query = &Query{}
					if right.As.String() != "" {
						join.Query.From.As = right.As.String()
					}
					switch rightExpr := right.Expr.(type) {
					case sqlparser.TableName:
						// log.Println("rightExpr:", jsonEncode(rightExpr))
						join.Query.From.Table = string(rightExpr.Name.String())
					case *sqlparser.Subquery:
						subQuery := &Query{}
						if err := subQuery.FromSelect(rightExpr.Select.(*sqlparser.Select)); err != nil {
							return err
						}
						join.Query.From.SubQuery = subQuery
					}
				}

				join.JoinWhere = &Where{}
				if err := join.JoinWhere.fromExpr(form.Condition.On); err != nil {
					return err
				}

				q.Join = append(q.Join, join)

				var ok bool
				form, ok = form.LeftExpr.(*sqlparser.JoinTableExpr)
				if !ok {
					break
				}
			}
		}

		// log.Println("selectStmt.From:", reflect.TypeOf(selectStmt.From), jsonEncode(selectStmt.From))
	}

	if selectStmt.GroupBy != nil {
		// log.Println("selectStmt.GroupBy:", reflect.TypeOf(selectStmt.GroupBy), jsonEncode(selectStmt.GroupBy))
		for _, v := range selectStmt.GroupBy {
			switch colName := v.(type) {
			case *sqlparser.ColName:
				q.GroupBy = append(q.GroupBy, Field{
					FromTable: colName.Qualifier.Name.String(),
					Name:      string(colName.Name.String()),
				})
			}
		}
	}

	if selectStmt.OrderBy != nil {
		// log.Println("selectStmt.OrderBy:", reflect.TypeOf(selectStmt.OrderBy), jsonEncode(selectStmt.OrderBy))
		for _, v := range selectStmt.OrderBy {
			switch colName := v.Expr.(type) {
			case *sqlparser.ColName:
				q.OrderBy = append(q.OrderBy, OrderByField{
					Field: Field{
						FromTable: colName.Qualifier.Name.String(),
						Name:      string(colName.Name.String()),
					},
					Direction: v.Direction,
				})
			}
		}
	}

	if selectStmt.Having != nil {
		// log.Println("selectStmt.Having:", reflect.TypeOf(selectStmt.Having), jsonEncode(selectStmt.Having))
		q.Having = nodeExtractRawSQL(selectStmt.Having.Expr)
	}

	if selectStmt.Limit != nil {
		// log.Println("selectStmt.Limit:", jsonEncode(selectStmt.Limit))
		if q.Limit == nil {
			q.Limit = &Limit{}
		}

		switch offset := selectStmt.Limit.Offset.(type) {
		case *sqlparser.SQLVal:
			q.Limit.Offset = cast.ToInt(fmt.Sprintf("%s", offset.Val))
		}
		switch count := selectStmt.Limit.Rowcount.(type) {
		case *sqlparser.SQLVal:
			q.Limit.Count = cast.ToInt(fmt.Sprintf("%s", count.Val))
		}
	}
	// log.Println("query:", jsonEncode(q))
	return nil
}

func (q *Query) FromSql(sql string) error {
	stmt, err := sqlparser.Parse(sql)
	if err != nil {
		return err
	}
	switch stmt.(type) {
	case *sqlparser.Select:
		selectStmt := stmt.(*sqlparser.Select)
		return q.FromSelect(selectStmt)
	default:
		return fmt.Errorf("unexpected type: %T", stmt)
	}
}

type DialectType string

const (
	POSTGRES  DialectType = "postgres"
	SQLITE                = "sqlite3"
	MYSQL                 = "mysql"
	MSSQL                 = "mssql"
	ORACLE                = "oracle"
	UNION                 = "union"
	INTERSECT             = "intersect"
	EXCEPT                = "except"
)

func (q *Query) ToBuilder() (*builder.Builder, error) {
	var dialect DialectType = MYSQL
	if q.Dialect != "" {
		dialect = q.Dialect
	}

	fields := []string{}
	for i := range q.Fields {
		name := q.Fields[i].Name

		if q.Fields[i].FromTable != "" {
			name = fmt.Sprintf("%s.`%s`", q.Fields[i].FromTable, name)
		}
		if q.Fields[i].As != "" {
			name = fmt.Sprintf("%s AS %s", name, q.Fields[i].As)
		}
		fields = append(fields, name)
	}
	b := builder.Dialect(string(dialect)).Select(fields...)

	if q.From.raw != "" {
		if q.From.As != "" {
			b = b.From(fmt.Sprintf("(%s)", q.From.raw), q.From.As)
		} else {
			b = b.From(fmt.Sprintf("(%s)", q.From.raw))
		}
	} else if q.From.Table != "" {
		if q.From.As != "" {
			b = b.From(q.From.Table, q.From.As)
		} else {
			b = b.From(q.From.Table)
		}
	} else {
		if q.From.SubQuery != nil {
			subBuilder, err := q.From.SubQuery.ToBuilder()
			if err != nil {
				return nil, err
			}
			if q.From.As != "" {
				b = b.From(subBuilder, q.From.As)
			} else {
				b = b.From(subBuilder)
			}
		}
	}

	if q.Join != nil {
		for _, join := range q.Join {
			if join.Query != nil {
				// log.Println("join:", jsonEncode(join))
				if join.Query.From.As == "" {
					return nil, fmt.Errorf("join table must have an alias")
				}

				if join.Query.From.raw != "" {

					cond, err := join.JoinWhere.ToCond()
					if err != nil {
						return nil, err
					}

					b = b.Join(join.Type, fmt.Sprintf("(%s)", join.Query.From.raw), cond, join.Query.From.As)

				} else if join.Query.From.SubQuery != nil {
					subBuilder, err := join.Query.From.SubQuery.ToBuilder()
					if err != nil {
						return nil, err
					}
					cond, err := join.JoinWhere.ToCond()
					if err != nil {
						return nil, err
					}
					b = b.Join(join.Type, subBuilder, cond, join.Query.From.As)
				} else {
					cond, err := join.JoinWhere.ToCond()
					if err != nil {
						return nil, err
					}
					b = b.Join(join.Type, join.Query.From.Table, cond, join.Query.From.As)
				}
			}
		}
	}

	if q.GroupBy != nil {
		groupBy := []string{}
		for i := range q.GroupBy {
			name := q.GroupBy[i].Name
			if q.GroupBy[i].FromTable != "" {
				name = fmt.Sprintf("%s.`%s`", q.GroupBy[i].FromTable, name)
			}
			groupBy = append(groupBy, name)
		}

		b = b.GroupBy(fmt.Sprintf("( %s )", strings.Join(groupBy, ", ")))
	}

	if q.OrderBy != nil {
		orderBy := []string{}
		for i := range q.OrderBy {
			name := q.OrderBy[i].Field.Name
			if q.OrderBy[i].Field.FromTable != "" {
				name = fmt.Sprintf("%s.`%s`", q.OrderBy[i].Field.FromTable, name)
			}
			if q.OrderBy[i].Direction != "" {
				name = fmt.Sprintf("%s %s", name, q.OrderBy[i].Direction)
			}
			orderBy = append(orderBy, name)
		}

		b = b.OrderBy(fmt.Sprintf("%s", strings.Join(orderBy, ", ")))
	}

	if q.Where != nil {
		cond, err := q.Where.ToCond()
		if err != nil {
			return nil, err
		}
		b = b.Where(cond)
	}

	if q.Having != "" {

		b = b.Having(q.Having)
	}

	if q.Limit != nil {
		b = b.Limit(q.Limit.Count, q.Limit.Offset)
	}
	return b, nil
}

func (q *Query) ToSql() (string, error) {
	b, err := q.ToBuilder()
	if err != nil {
		return "", fmt.Errorf("failed to build query: %w", err)
	}

	return b.ToBoundSQL()
}