package util

import (
	"sync"

	"github.com/evcc-io/evcc/api"
)

// TeeAttacher allows attaching a listener to a tee
type TeeAttacher interface {
	Attach() <-chan Param
}

// Tee distributes parameters to subscribers
type Tee struct {
	mu   sync.Mutex
	recv []chan<- Param
}

// Attach creates a new receiver channel and attaches it to the tee
func (t *Tee) Attach() <-chan Param {
	// TODO find better approach to prevent deadlocks
	// this will buffer the receiver channel to prevent deadlocks when consumers use mutex-protected loadpoint api
	out := make(chan Param, 128)
	t.add(out)
	return out
}

// add attaches a receiver channel to the tee
func (t *Tee) add(out chan<- Param) {
	t.mu.Lock()
	defer t.mu.Unlock()
	t.recv = append(t.recv, out)
}

// Run starts parameter distribution
func (t *Tee) Run(in <-chan Param) {
	for msg := range in {
		// TODO MUST NOT PUBLISH POINTERS (WHO'S VALUES ARE LATER MODIFIED)
		// if val := reflect.ValueOf(msg.Val); val.Kind() == reflect.Pointer {
		// 	if ptr := reflect.Indirect(val); ptr.IsValid() {
		// 		fmt.Println("DANGER pointer value:", msg.Key)
		// 	}
		// }

		if val, ok := (msg.Val).(api.Redactor); ok {
			msg.Val = val.Redacted()
		}

		t.mu.Lock()
		for _, recv := range t.recv {
			recv <- msg
		}
		t.mu.Unlock()
	}
}