// FindInstanceSpec returns an InstanceSpec satisfying the supplied instanceConstraint.
func (env *joyentEnviron) FindInstanceSpec(ic *instances.InstanceConstraint) (*instances.InstanceSpec, error) {
	// Require at least one VCPU so we get KVM rather than smart package.
	if ic.Constraints.CpuCores == nil {
		ic.Constraints.CpuCores = &defaultCpuCores
	}
	allInstanceTypes, err := env.listInstanceTypes()
	if err != nil {
		return nil, err
	}
	imageConstraint := imagemetadata.NewImageConstraint(simplestreams.LookupParams{
		CloudSpec: simplestreams.CloudSpec{ic.Region, env.Ecfg().SdcUrl()},
		Series:    []string{ic.Series},
		Arches:    ic.Arches,
	})
	sources, err := environs.ImageMetadataSources(env)
	if err != nil {
		return nil, err
	}

	matchingImages, _, err := imagemetadata.Fetch(sources, imageConstraint, signedImageDataOnly)
	if err != nil {
		return nil, err
	}
	images := instances.ImageMetadataToImages(matchingImages)
	spec, err := instances.FindInstanceSpec(images, ic, allInstanceTypes)
	if err != nil {
		return nil, err
	}
	return spec, nil
}

// findInstanceSpec returns an InstanceSpec satisfying the supplied instanceConstraint.
func findInstanceSpec(
	allImageMetadata []*imagemetadata.ImageMetadata,
	ic *instances.InstanceConstraint,
) (*instances.InstanceSpec, error) {

	// If the instance type is set, don't also set a default CPU power
	// as this is implied.
	cons := ic.Constraints
	if cons.CpuPower == nil && (cons.InstanceType == nil || *cons.InstanceType == "") {
		ic.Constraints.CpuPower = instances.CpuPower(defaultCpuPower)
	}
	suitableImages := filterImages(allImageMetadata, ic)
	images := instances.ImageMetadataToImages(suitableImages)

	// Make a copy of the known EC2 instance types, filling in the cost for the specified region.
	regionCosts := allRegionCosts[ic.Region]
	if len(regionCosts) == 0 && len(allRegionCosts) > 0 {
		return nil, fmt.Errorf("no instance types found in %s", ic.Region)
	}

	var itypesWithCosts []instances.InstanceType
	for _, itype := range allInstanceTypes {
		cost, ok := regionCosts[itype.Name]
		if !ok {
			continue
		}
		itWithCost := itype
		itWithCost.Cost = cost
		itypesWithCosts = append(itypesWithCosts, itWithCost)
	}
	return instances.FindInstanceSpec(images, ic, itypesWithCosts)
}

// findInstanceSpec returns the InstanceSpec that best satisfies the supplied
// InstanceConstraint.
//
// NOTE(axw) for now we ignore simplestreams altogether, and go straight to
// Azure's image registry.
func findInstanceSpec(
	client compute.VirtualMachineImagesClient,
	instanceTypesMap map[string]instances.InstanceType,
	constraint *instances.InstanceConstraint,
	imageStream string,
) (*instances.InstanceSpec, error) {

	if !constraintHasArch(constraint, arch.AMD64) {
		// Azure only supports AMD64.
		return nil, errors.NotFoundf("%s in arch constraints", arch.AMD64)
	}

	image, err := imageutils.SeriesImage(constraint.Series, imageStream, constraint.Region, client)
	if err != nil {
		return nil, errors.Trace(err)
	}
	images := []instances.Image{*image}

	instanceTypes := make([]instances.InstanceType, 0, len(instanceTypesMap))
	for _, instanceType := range instanceTypesMap {
		instanceTypes = append(instanceTypes, instanceType)
	}
	constraint.Constraints = defaultToBaselineSpec(constraint.Constraints)
	return instances.FindInstanceSpec(images, constraint, instanceTypes)
}

// findInstanceSpec initializes a new instance spec for the given
// constraints and returns it. This only covers populating the
// initial data for the spec.
func (env *environ) findInstanceSpec(
	ic *instances.InstanceConstraint,
	imageMetadata []*imagemetadata.ImageMetadata,
) (*instances.InstanceSpec, error) {
	images := instances.ImageMetadataToImages(imageMetadata)
	spec, err := instances.FindInstanceSpec(images, ic, allInstanceTypes)
	return spec, errors.Trace(err)
}

// findInstanceSpec returns the InstanceSpec that best satisfies the supplied
// InstanceConstraint.
func findInstanceSpec(env *azureEnviron, constraint *instances.InstanceConstraint) (*instances.InstanceSpec, error) {
	constraint.Constraints = defaultToBaselineSpec(constraint.Constraints)
	imageData, err := findMatchingImages(env, constraint.Region, constraint.Series, constraint.Arches)
	if err != nil {
		return nil, err
	}
	images := instances.ImageMetadataToImages(imageData)
	instanceTypes, err := listInstanceTypes(env)
	if err != nil {
		return nil, err
	}
	return instances.FindInstanceSpec(images, constraint, instanceTypes)
}

// findInstanceSpec returns an image and instance type satisfying the constraint.
// The instance type comes from querying the flavors supported by the deployment.
func findInstanceSpec(
	e *Environ,
	ic *instances.InstanceConstraint,
	imageMetadata []*imagemetadata.ImageMetadata,
) (*instances.InstanceSpec, error) {
	// First construct all available instance types from the supported flavors.
	nova := e.nova()
	flavors, err := nova.ListFlavorsDetail()
	if err != nil {
		return nil, err
	}
	// Not all needed information is available in flavors,
	// for e.g. architectures or virtualisation types.
	// For these properties, we assume that all instance types support
	// all values.
	allInstanceTypes := []instances.InstanceType{}
	for _, flavor := range flavors {
		instanceType := instances.InstanceType{
			Id:       flavor.Id,
			Name:     flavor.Name,
			Arches:   ic.Arches,
			Mem:      uint64(flavor.RAM),
			CpuCores: uint64(flavor.VCPUs),
			RootDisk: uint64(flavor.Disk * 1024),
			// tags not currently supported on openstack
		}
		if ic.Constraints.HasVirtType() {
			// Instance Type virtual type depends on the virtual type of the selected image, i.e.
			// picking an image with a virt type gives a machine with this virt type.
			instanceType.VirtType = ic.Constraints.VirtType
		}
		allInstanceTypes = append(allInstanceTypes, instanceType)
	}

	images := instances.ImageMetadataToImages(imageMetadata)
	spec, err := instances.FindInstanceSpec(images, ic, allInstanceTypes)
	if err != nil {
		return nil, err
	}

	// If instance constraints did not have a virtualisation type,
	// but image metadata did, we will have an instance type
	// with virtualisation type of an image.
	if !ic.Constraints.HasVirtType() && spec.Image.VirtType != "" {
		spec.InstanceType.VirtType = &spec.Image.VirtType
	}
	return spec, nil
}

// findInstanceSpec returns an InstanceSpec satisfying the supplied instanceConstraint.
func findInstanceSpec(
	sources []simplestreams.DataSource, stream string, ic *instances.InstanceConstraint) (*instances.InstanceSpec, error) {

	// If the instance type is set, don't also set a default CPU power
	// as this is implied.
	cons := ic.Constraints
	if cons.CpuPower == nil && (cons.InstanceType == nil || *cons.InstanceType == "") {
		ic.Constraints.CpuPower = instances.CpuPower(defaultCpuPower)
	}
	ec2Region := allRegions[ic.Region]
	imageConstraint := imagemetadata.NewImageConstraint(simplestreams.LookupParams{
		CloudSpec: simplestreams.CloudSpec{ic.Region, ec2Region.EC2Endpoint},
		Series:    []string{ic.Series},
		Arches:    ic.Arches,
		Stream:    stream,
	})
	matchingImages, _, err := imagemetadata.Fetch(sources, imageConstraint, signedImageDataOnly)
	if err != nil {
		return nil, err
	}
	if len(matchingImages) == 0 {
		logger.Warningf("no matching image meta data for constraints: %v", ic)
	}
	suitableImages := filterImages(matchingImages, ic)
	images := instances.ImageMetadataToImages(suitableImages)

	// Make a copy of the known EC2 instance types, filling in the cost for the specified region.
	regionCosts := allRegionCosts[ic.Region]
	if len(regionCosts) == 0 && len(allRegionCosts) > 0 {
		return nil, fmt.Errorf("no instance types found in %s", ic.Region)
	}

	var itypesWithCosts []instances.InstanceType
	for _, itype := range allInstanceTypes {
		cost, ok := regionCosts[itype.Name]
		if !ok {
			continue
		}
		itWithCost := itype
		itWithCost.Cost = cost
		itypesWithCosts = append(itypesWithCosts, itWithCost)
	}
	return instances.FindInstanceSpec(images, ic, itypesWithCosts)
}

// FindInstanceSpec returns an InstanceSpec satisfying the supplied instanceConstraint.
func (env *joyentEnviron) FindInstanceSpec(
	ic *instances.InstanceConstraint,
	imageMetadata []*imagemetadata.ImageMetadata,
) (*instances.InstanceSpec, error) {
	// Require at least one VCPU so we get KVM rather than smart package.
	if ic.Constraints.CpuCores == nil {
		ic.Constraints.CpuCores = &defaultCpuCores
	}
	allInstanceTypes, err := env.listInstanceTypes()
	if err != nil {
		return nil, err
	}
	images := instances.ImageMetadataToImages(imageMetadata)
	spec, err := instances.FindInstanceSpec(images, ic, allInstanceTypes)
	if err != nil {
		return nil, err
	}
	return spec, nil
}

// findInstanceSpec returns an image and instance type satisfying the constraint.
// The instance type comes from querying the flavors supported by the deployment.
func findInstanceSpec(e *environ, ic *instances.InstanceConstraint) (*instances.InstanceSpec, error) {
	// first construct all available instance types from the supported flavors.
	nova := e.nova()
	flavors, err := nova.ListFlavorsDetail()
	if err != nil {
		return nil, err
	}
	allInstanceTypes := []instances.InstanceType{}
	for _, flavor := range flavors {
		instanceType := instances.InstanceType{
			Id:       flavor.Id,
			Name:     flavor.Name,
			Arches:   ic.Arches,
			Mem:      uint64(flavor.RAM),
			CpuCores: uint64(flavor.VCPUs),
			RootDisk: uint64(flavor.Disk * 1024),
			// tags not currently supported on openstack
		}
		allInstanceTypes = append(allInstanceTypes, instanceType)
	}

	imageConstraint := imagemetadata.NewImageConstraint(simplestreams.LookupParams{
		CloudSpec: simplestreams.CloudSpec{ic.Region, e.ecfg().authURL()},
		Series:    []string{ic.Series},
		Arches:    ic.Arches,
		Stream:    e.Config().ImageStream(),
	})
	sources, err := imagemetadata.GetMetadataSources(e)
	if err != nil {
		return nil, err
	}
	// TODO (wallyworld): use an env parameter (default true) to mandate use of only signed image metadata.
	matchingImages, _, err := imagemetadata.Fetch(sources, simplestreams.DefaultIndexPath, imageConstraint, false)
	if err != nil {
		return nil, err
	}
	images := instances.ImageMetadataToImages(matchingImages)
	spec, err := instances.FindInstanceSpec(images, ic, allInstanceTypes)
	if err != nil {
		return nil, err
	}
	return spec, nil
}

// findInstanceSpec initializes a new instance spec for the given stream
// (and constraints) and returns it. This only covers populating the
// initial data for the spec. However, it does include fetching the
// correct simplestreams image data.
func (env *environ) findInstanceSpec(stream string, ic *instances.InstanceConstraint) (*instances.InstanceSpec, error) {
	sources, err := environs.ImageMetadataSources(env)
	if err != nil {
		return nil, errors.Trace(err)
	}

	imageConstraint := imagemetadata.NewImageConstraint(simplestreams.LookupParams{
		CloudSpec: env.cloudSpec(ic.Region),
		Series:    []string{ic.Series},
		Arches:    ic.Arches,
		Stream:    stream,
	})

	signedImageDataOnly := false
	matchingImages, _, err := imageMetadataFetch(sources, imageConstraint, signedImageDataOnly)
	if err != nil {
		return nil, errors.Trace(err)
	}

	images := instances.ImageMetadataToImages(matchingImages)
	spec, err := instances.FindInstanceSpec(images, ic, allInstanceTypes)
	return spec, errors.Trace(err)
}