package disk

import "fmt"

type LVMVolumeGroup struct {
	Name        string
	Description string

	LogicalVolumes []LVMLogicalVolume
}

func (vg *LVMVolumeGroup) IsContainer() bool {
	return true
}

func (vg *LVMVolumeGroup) Clone() Entity {
	if vg == nil {
		return nil
	}

	clone := &LVMVolumeGroup{
		Name:           vg.Name,
		Description:    vg.Description,
		LogicalVolumes: make([]LVMLogicalVolume, len(vg.LogicalVolumes)),
	}

	for idx, lv := range vg.LogicalVolumes {
		ent := lv.Clone()
		var lv *LVMLogicalVolume
		if ent != nil {
			lvEnt, cloneOk := ent.(*LVMLogicalVolume)
			if !cloneOk {
				panic("LVMLogicalVolume.Clone() returned an Entity that cannot be converted to *LVMLogicalVolume; this is a programming error")
			}
			lv = lvEnt
		}
		clone.LogicalVolumes[idx] = *lv
	}

	return clone
}

func (vg *LVMVolumeGroup) GetItemCount() uint {
	if vg == nil {
		return 0
	}
	return uint(len(vg.LogicalVolumes))
}

func (vg *LVMVolumeGroup) GetChild(n uint) Entity {
	if vg == nil {
		panic("LVMVolumeGroup.GetChild: nil entity")
	}
	return &vg.LogicalVolumes[n]
}

func (vg *LVMVolumeGroup) CreateVolume(mountpoint string, size uint64) (Entity, error) {
	if vg == nil {
		panic("LVMVolumeGroup.CreateVolume: nil entity")
	}
	filesystem := Filesystem{
		Type:         "xfs",
		Mountpoint:   mountpoint,
		FSTabOptions: "defaults",
		FSTabFreq:    0,
		FSTabPassNo:  0,
	}

	lv := LVMLogicalVolume{
		Size:    size,
		Payload: &filesystem,
	}

	vg.LogicalVolumes = append(vg.LogicalVolumes, lv)

	return &vg.LogicalVolumes[len(vg.LogicalVolumes)-1], nil
}

type LVMLogicalVolume struct {
	Name    string
	Size    uint64
	Payload Entity
}

func (lv *LVMLogicalVolume) IsContainer() bool {
	return true
}

func (lv *LVMLogicalVolume) Clone() Entity {
	if lv == nil {
		return nil
	}
	return &LVMLogicalVolume{
		Name:    lv.Name,
		Size:    lv.Size,
		Payload: lv.Payload,
	}
}

func (lv *LVMLogicalVolume) GetItemCount() uint {
	if lv == nil || lv.Payload == nil {
		return 0
	}
	return 1
}

func (lv *LVMLogicalVolume) GetChild(n uint) Entity {
	if n != 0 || lv == nil {
		panic(fmt.Sprintf("invalid child index for LVMLogicalVolume: %d != 0", n))
	}
	return lv.Payload
}

func (lv *LVMLogicalVolume) GetSize() uint64 {
	if lv == nil {
		return 0
	}
	return lv.Size
}

func (lv *LVMLogicalVolume) EnsureSize(s uint64) bool {
	if lv == nil {
		panic("LVMLogicalVolume.EnsureSize: nil entity")
	}
	if s > lv.Size {
		lv.Size = s
		return true
	}
	return false
}