package helm

import (
	"embed"
	"fmt"

	"sigs.k8s.io/yaml"

	l5dvalues "edge-infra.dev/pkg/edge/linkerd/helm/values"
)

//go:embed linkerd/charts/*
//go:embed linkerd/charts/partials/templates/**.tpl

// Templates contains the static chart templates for Linkerd2
var Templates embed.FS

//go:embed .version
var Version string

const (
	ControlPath       = "linkerd/charts/linkerd-control-plane"
	CrdPath           = "linkerd/charts/linkerd-crds"
	Policies          = "templates/policy"
	PartialsChartPath = "linkerd/charts/partials"

	Registry = "ghcr.io/linkerd"
	// Image Names.  Needed to override the container registry URLs, because the
	// Linkerd chart specifies images by repo + name (e.g., cr.l5d.io/linkerd/policy-controller)
	PolicyControllerImage = "policy-controller"
	ProxyImage            = "proxy"
	ProxyInitImage        = "proxy-init"
	ControllerImage       = "controller"
	DebugImage            = "debug"
)

// DefaultValues reads the contents of the values.yaml shipped with the Linkerd
// Helm Chart, unmarshals it into the linkerd2.Values{} struct, and then sets
// some values which always need updating before returning the result. These are
// the unopinionated defaults based on the upstream chart.  Edge specific defaults
// are defined in pkg/edge/linkerd.
//
// A general rule of thumb is that this function should only set values that are
// constants that would typically be set by the L5d Helm Chart publishing process --
// everything else should go into pkg/edge/linkerd/render as a rendering option.
func DefaultValues() (*l5dvalues.Values, error) {
	// read the bundled values.yaml for linkerd-control-plane and linkerd-crds charts and merges them together
	// linkerd-crds is required to render the HTTPRoutes CRD introduced into linkerd 2.14.5
	//
	// We will need https://github.com/linkerd/linkerd2/issues/11869 resolved so linkerd deploys the HTTPRoutes CRD,
	// instead of us manually deploying it via the linkerdctl pallet.
	v, err := readDefaults(CrdPath + "/values.yaml")
	if err != nil {
		return nil, err
	}

	vCP, err := readDefaults(ControlPath + "/values.yaml")
	if err != nil {
		return nil, err
	}

	*v, err = v.Merge(*vCP)
	if err != nil {
		return nil, err
	}

	// set correct defaults
	v.CliVersion = Version
	v.LinkerdVersion = Version
	v.PolicyController.Image.Version = Version
	v.Proxy.Image.Version = Version
	// heartbeat prometheus URL is hardcoded to l5d's prometheus, which we dont use
	v.DisableHeartBeat = true

	return v, nil
}

func readDefaults(p string) (*l5dvalues.Values, error) {
	// read the bundled values.yaml
	raw, err := Templates.ReadFile(p)
	if err != nil {
		return nil, fmt.Errorf("failed to read %s: %w", p, err)
	}

	// unmarshal it into Values{} struct
	v := &l5dvalues.Values{}
	err = yaml.Unmarshal(raw, &v)
	if err != nil {
		return nil, fmt.Errorf("failed to unmarshal values data into values struct: %w", err)
	}
	return v, nil
}