package common

type Config interface {
	Name() string
	Starter() StartFct
	Children() []Config
	Add(Config)
}

type Services map[string]Context

type Context interface {
	Config() Config
	Parent() Context
	Services() Services
	ChildContext(Config) Context
}

type StartFct = func(Context)

// Context implementation

type context struct {
	cfg      Config
	parent   Context
	children []Context
}

func (ctx *context) Config() Config {
	return ctx.cfg
}

func (ctx *context) Parent() Context {
	return ctx.parent
}

func (ctx *context) Services() Services {
	return ctx.parent.Services()
}

func (ctx *context) ChildContext(cfg Config) Context {
	cctx := makeCtx(cfg, ctx)
	ctx.Services()[cfg.Name()] = cctx
	ctx.children = append(ctx.children, cctx)
	return cctx
}

func makeCtx(cfg Config, parent Context) *context {
	return &context{cfg, parent, nil}
}

// top-level application context

type appContext struct {
	*context
	services Services
}

func (ctx *appContext) ChildContext(cfg Config) Context {
	cctx := makeCtx(cfg, ctx)
	ctx.services[cfg.Name()] = cctx
	ctx.children = append(ctx.children, cctx)
	return cctx
}

func (ctx *appContext) Services() Services {
	return ctx.services
}

func AppContext(cfg Config) Context {
	return &appContext{
		context:  makeCtx(cfg, nil),
		services: Services{},
	}
}