package devicepath

import (
	"errors"
	"fmt"
	"strings"
)

var (
	ErrUnknownSubType  = errors.New("unknown device sub-type")
	ErrMalformedString = errors.New("malformed device string")
)

type ErrInvalidArguments struct {
	subErr error
}

func (e *ErrInvalidArguments) Error() string {
	return fmt.Sprintf("invalid argument: %s", e.subErr.Error())
}

type ErrInvalidPath struct {
	subErr error
	node   string
}

func (e *ErrInvalidPath) Error() string {
	return fmt.Sprintf("invalid device path on section %q: %s", e.node, e.subErr.Error())
}

type nodeGenerator func() DevicePathNode

var prefixTypeAssociation = map[string]nodeGenerator{
	sataPrefix:    func() DevicePathNode { return &SataDevicePath{} },
	pciPrefix:     func() DevicePathNode { return &PCIDevicePath{} },
	pciRootPrefix: func() DevicePathNode { return &PCIRootDevicePath{} },
}

func Parsenode(raw string) (DevicePathNode, error) {
	prefix := getPrefix(raw)
	devGen, ok := prefixTypeAssociation[prefix]
	if !ok {
		return nil, ErrUnknownSubType
	}
	dev := devGen()
	if err := dev.ParseString(raw); err != nil {
		return nil, &ErrInvalidArguments{subErr: err}
	}
	return dev, nil
}

func ParseDevicePath(raw string) (*DevicePath, error) {
	dp := DevicePath{}
	for _, nodeStr := range strings.Split(raw, "/") {
		node, err := Parsenode(nodeStr)
		if err != nil {
			return nil, &ErrInvalidPath{subErr: err, node: nodeStr}
		}
		if err := dp.PushNode(node); err != nil {
			return nil, err
		}
	}
	dp.PushNode(&FinalDevicePath{})
	return &dp, nil
}