package query

import (
	"fmt"

	"github.com/influxdata/influxql"
)

type IteratorMap interface {
	Value(row *Row) interface{}
}

type FieldMap int

func (i FieldMap) Value(row *Row) interface{} { return row.Values[i] }

type TagMap string

func (s TagMap) Value(row *Row) interface{} { return row.Series.Tags.Value(string(s)) }

type NullMap struct{}

func (NullMap) Value(row *Row) interface{} { return nil }

func NewIteratorMapper(cur Cursor, driver IteratorMap, fields []IteratorMap, opt IteratorOptions) Iterator {
	if driver != nil {
		switch driver := driver.(type) {
		case FieldMap:
			switch typ := cur.Columns()[int(driver)].Type; typ {
			case influxql.Float:
				return newFloatIteratorMapper(cur, driver, fields, opt)
			case influxql.Integer:
				return newIntegerIteratorMapper(cur, driver, fields, opt)
			case influxql.Unsigned:
				return newUnsignedIteratorMapper(cur, driver, fields, opt)
			case influxql.String:
				return newStringIteratorMapper(cur, driver, fields, opt)
			case influxql.Boolean:
				return newBooleanIteratorMapper(cur, driver, fields, opt)
			default:
				panic(fmt.Sprintf("unable to map iterator type: %s", typ))
			}
		case TagMap:
			return newStringIteratorMapper(cur, driver, fields, opt)
		default:
			panic(fmt.Sprintf("unable to create iterator mapper with driver expression type: %T", driver))
		}
	}
	return newFloatIteratorMapper(cur, nil, fields, opt)
}