parser

type Array struct {
	Value []*Value `parser:" '(' @@ ( ',' @@ )* ')' "`
}

type Boolean bool

type Column struct {
	Name  string `parser:"( @Ident | @String )"`
	Alias string `parser:" ( 'AS' ( @Ident | @String | @'FROM' | @'NAMESPACE' | @'NS' | @'NAME' | @'SELECT' | @'LABEL' | @'DESC' ) )? "`
}

type Compare struct {
	NOT bool   `parser:" @'NOT'? "`
	LHS string `parser:" ( @Ident | @String ) "`
	Op  string `parser:" @( '<>' | '<=' | '>=' | '=' | '==' | '<' | '>' | '!=' | 'NOT'? 'IN' ) "`
	RHS Value  `parser:" @@ "`
}

type Condition struct {
	Type    string  `parser:" @( 'AND' | 'OR' ) "`
	Compare Compare `parser:" @@ "`
}

type DeleteStat struct {
	From              FromExpr            `parser:" 'DELETE' 'FROM' @@ "`
	Where             *WhereExpr          `parser:" ( 'WHERE' @@ )? "`
	Namespace         string              `parser:" ( ( 'NAMESPACE' | 'NS' ) ( @Ident | @String ) )? "`
	KubernetesFilters []*KubernetesFilter `parser:" @@* "`
}

type DescStat struct {
	Table string `parser:" 'DESC' @Ident "`
}

type FromExpr struct {
	Table string `parser:" ( @Ident | @'NAMESPACE' | @'NS' | @'NAME' | @'SELECT' | @'LABEL' ) "`
	DB    string `parser:" ( '@' @Ident )? "`
}

type KSQL struct {
	Use    *UseStat    `parser:" @@* "`
	Select *SelectStat `parser:" @@* "`

	// TODO
	Delete *DeleteStat `parser:" @@* "`
	Update *UpdateStat `parser:" @@* "`

	Desc *DescStat `parser:" @@* "`
}

type KubernetesFilter struct {
	Label *LabelCompare `parser:"   'LABEL' @@ "`
	Name  *string       `parser:" | 'NAME' (@Ident | @String) "`
}

type LabelCompare struct {
	LHS       string         `parser:" ( @Ident | @String ) "`
	Operation LabelOperation `parser:" @@ "`
}

type LabelOperation struct {
	Exists string `parser:" ( @( 'NOT'? 'EXISTS') "`
	Op     string `parser:" | @( '<>' | '<=' | '>=' | '=' | '==' | '!=' | 'NOT'? 'IN' ) "`
	RHS    Value  `parser:" @@ ) "`
}

type SelectExpr struct {
	ALL     bool      `parser:" @'*' "`
	Columns []*Column `parser:" | @@ ( ',' @@ )* "`
}

type SelectStat struct {
	Select            SelectExpr          `parser:" 'SELECT' @@ "`
	From              FromExpr            `parser:" 'FROM' @@ "`
	Where             *WhereExpr          `parser:" ( 'WHERE' @@ )? "`
	Namespace         string              `parser:" ( ( 'NAMESPACE' | 'NS' ) ( @Ident | @String )? )? "`
	KubernetesFilters []*KubernetesFilter `parser:" @@* "`
}

type Statement interface{}

type UpdateStat struct {
	Update bool `parser:" @'UPDATE' "`
}

type UseStat struct {
	// Database, we consider each cluster is a database.
	Database string `parser:" 'USE' @Ident "`
}

type Value struct {
	Number  *float64 ` parser:" ( @Number "`
	String  *string  ` parser:" | @String | @Ident "`
	Boolean *Boolean ` parser:" | @('TRUE' | 'FALSE') "`
	Null    bool     ` parser:" | @'NULL' "`
	Array   *Array   ` parser:" | @@ )"`
}

type WhereExpr struct {
	First      Compare      `parser:" @@ "`
	Conditions []*Condition `parser:" @@* "`
}