/*
Copyright 2022 The Karmada Authors.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

package context

import (
	"k8s.io/apimachinery/pkg/util/sets"
	"k8s.io/klog/v2"
	controllerruntime "sigs.k8s.io/controller-runtime"
)

// Context defines the context object for controller
type Context struct {
	// Controllers is the list of controllers to enable or disable
	// '*' means "all enabled by default controllers"
	// 'foo' means "enable 'foo'"
	// '-foo' means "disable 'foo'"
	// first item for a particular name wins
	Controllers []string

	Manager controllerruntime.Manager
}

// IsControllerEnabled checks if the context's controllers enabled or not
func (c Context) IsControllerEnabled(name string, disabledByDefaultControllers sets.Set[string]) bool {
	hasStar := false
	for _, ctrl := range c.Controllers {
		if ctrl == name {
			return true
		}
		if ctrl == "-"+name {
			return false
		}
		if ctrl == "*" {
			hasStar = true
		}
	}
	// if we get here, there was no explicit choice
	if !hasStar {
		// nothing on by default
		return false
	}

	return !disabledByDefaultControllers.Has(name)
}

// InitFunc is used to launch a particular controller.
// Any error returned will cause the controller process to `Fatal`
// The bool indicates whether the controller was enabled.
type InitFunc func(ctx Context) (enabled bool, err error)

// Initializers is a public map of named controller groups
type Initializers map[string]InitFunc

// ControllerNames returns all known controller names
func (i Initializers) ControllerNames() []string {
	return sets.StringKeySet(i).List()
}

// StartControllers starts a set of controllers with a specified ControllerContext
func (i Initializers) StartControllers(ctx Context, controllersDisabledByDefault sets.Set[string]) error {
	for controllerName, initFn := range i {
		if !ctx.IsControllerEnabled(controllerName, controllersDisabledByDefault) {
			klog.Warningf("%q is disabled", controllerName)
			continue
		}
		klog.V(1).Infof("Starting %q", controllerName)
		started, err := initFn(ctx)
		if err != nil {
			klog.Errorf("Error starting %q", controllerName)
			return err
		}
		if !started {
			klog.Warningf("Skipping %q", controllerName)
			continue
		}
		klog.Infof("Started %q", controllerName)
	}
	return nil
}