package vmysql

import (
	"vitess.io/vitess/go/sqltypes"
	"vitess.io/vitess/go/vt/proto/query"
)

type Column struct {
	// Name is the name of the column.
	Name string
	// Type is the data type of the column.
	Type query.Type
	// Default contains the default value of the column or nil if it is NULL.
	Default interface{}
	// Nullable is true if the column can contain NULL values, or false
	// otherwise.
	Nullable bool
	// Source is the name of the table this column came from.
	Source string
	// PrimaryKey is true if the column is part of the primary key for its table.
	PrimaryKey bool
}

type Schema []*Column
type SQLRow []interface{}

func SchemaToFields(s Schema) []*query.Field {
	fields := make([]*query.Field, len(s))
	for i, c := range s {
		var charset uint32 = CharacterSetUtf8
		if c.Type == sqltypes.Blob {
			charset = CharacterSetBinary
		}

		fields[i] = &query.Field{
			Name:    c.Name,
			Type:    c.Type,
			Charset: charset,
		}
	}
	return fields
}

func RowToSQL(row SQLRow) []sqltypes.Value {
	o := make([]sqltypes.Value, len(row))

	for i, v := range row {
		switch value := v.(type) {
		case []byte:
			o[i] = sqltypes.MakeTrusted(sqltypes.Blob, value)
		case string:
			o[i] = sqltypes.MakeTrusted(sqltypes.Text, []byte(value))
		default:
			o[i] = sqltypes.MakeTrusted(sqltypes.Blob, []byte{})
		}
	}

	return o
}

func GetMysqlVars() *sqltypes.Result {
	r := &sqltypes.Result{Fields: SchemaToFields(Schema{
		{Name: "system_time_zone", Type: sqltypes.Text, Nullable: false},
		{Name: "time_zone", Type: sqltypes.Text, Nullable: false},
		{Name: "init_connect", Type: sqltypes.Text, Nullable: false},
		{Name: "auto_increment_increment", Type: sqltypes.Text, Nullable: false},
		{Name: "max_allowed_packet", Type: sqltypes.Text, Nullable: false},
	})}
	r.Rows = append(r.Rows, RowToSQL(SQLRow{"UTC", "SYSTEM", "", "1", "10000"}))
	return r
}