package backpack

import (
	"fmt"
	"sync"

	"git.golem15.com/golem15/summercms/compass"
	"git.golem15.com/golem15/summercms/modules/festival"
)

// App is the per-instance application container. It must not import party.
type App struct {
	Config   *compass.Config
	Services *Registry
	Events   *festival.Bus

	mu      sync.RWMutex
	plugins map[string]struct{}
}

// New returns an App that owns cfg.
func New(cfg *compass.Config) *App {
	return &App{
		Config:   cfg,
		Services: NewRegistry(),
		Events:   festival.New(),
		plugins:  make(map[string]struct{}),
	}
}

// SetPlugins records the complete activated plugin set. HasPlugin uses this
// list, including plugins that have not yet Booted.
func (a *App) SetPlugins(ids []string) {
	if a == nil {
		return
	}
	next := make(map[string]struct{}, len(ids))
	for _, id := range ids {
		if id != "" {
			next[id] = struct{}{}
		}
	}
	a.mu.Lock()
	a.plugins = next
	a.mu.Unlock()
}

// HasPlugin reports whether id is in the complete registered set.
func (a *App) HasPlugin(id string) bool {
	if a == nil {
		return false
	}
	a.mu.RLock()
	defer a.mu.RUnlock()
	_, ok := a.plugins[id]
	return ok
}

// Publish stores an app-scoped service under T.
func (a *App) Publish[T any](value T) error {
	if a == nil || a.Services == nil {
		return fmt.Errorf("backpack: app has no service registry")
	}
	return a.Services.Publish(value)
}

// Lookup returns the app-scoped service published under T.
func (a *App) Lookup[T any]() (T, bool) {
	var zero T
	if a == nil || a.Services == nil {
		return zero, false
	}
	return a.Services.Lookup[T]()
}