package rest

import "context"

type Delegate interface {
	BeforeQuery(ctx context.Context, query *Query) (err error)
	AfterQuery(ctx context.Context, query *Query) (err error)
	BeforeSave(ctx context.Context, model interface{}) (err error)
	AfterSave(ctx context.Context, model interface{}, diff []*DiffAttr) (err error)
	BeforeCreate(ctx context.Context, model interface{}) (err error)
	AfterCreate(ctx context.Context, model interface{}, diff []*DiffAttr) (err error)
	BeforeUpdate(ctx context.Context, model interface{}) (err error)
	AfterUpdate(ctx context.Context, model interface{}, diff []*DiffAttr) (err error)
	BeforeDelete(ctx context.Context, model interface{}) (err error)
	AfterDelete(ctx context.Context, model interface{}) (err error)
}

type delegate struct {
	delegates []Delegate
}

func (dm *delegate) Register(d Delegate) {
	if dm.delegates == nil {
		dm.delegates = make([]Delegate, 0)
	}
	dm.delegates = append(dm.delegates, d)
}

func (dm *delegate) BeforeQuery(ctx context.Context, query *Query) (err error) {
	for i := len(dm.delegates) - 1; i >= 0; i-- {
		if err = dm.delegates[i].BeforeQuery(ctx, query); err != nil {
			return
		}
	}
	return
}

func (dm *delegate) AfterQuery(ctx context.Context, query *Query) (err error) {
	for i := len(dm.delegates) - 1; i >= 0; i-- {
		if err = dm.delegates[i].AfterQuery(ctx, query); err != nil {
			return
		}
	}
	return
}

func (dm *delegate) BeforeSave(ctx context.Context, model interface{}) (err error) {
	for i := len(dm.delegates) - 1; i >= 0; i-- {
		if err = dm.delegates[i].BeforeSave(ctx, model); err != nil {
			return
		}
	}
	return
}

func (dm *delegate) AfterSave(ctx context.Context, model interface{}, diff []*DiffAttr) (err error) {
	for i := len(dm.delegates) - 1; i >= 0; i-- {
		if err = dm.delegates[i].AfterSave(ctx, model, diff); err != nil {
			return
		}
	}
	return
}

func (dm *delegate) BeforeCreate(ctx context.Context, model interface{}) (err error) {
	for i := len(dm.delegates) - 1; i >= 0; i-- {
		if err = dm.delegates[i].BeforeCreate(ctx, model); err != nil {
			return
		}
	}
	return
}

func (dm *delegate) AfterCreate(ctx context.Context, model interface{}, diff []*DiffAttr) (err error) {
	for i := len(dm.delegates) - 1; i >= 0; i-- {
		if err = dm.delegates[i].AfterCreate(ctx, model, diff); err != nil {
			return
		}
	}
	return
}

func (dm *delegate) BeforeUpdate(ctx context.Context, model interface{}) (err error) {
	for i := len(dm.delegates) - 1; i >= 0; i-- {
		if err = dm.delegates[i].BeforeUpdate(ctx, model); err != nil {
			return
		}
	}
	return
}

func (dm *delegate) AfterUpdate(ctx context.Context, model interface{}, diff []*DiffAttr) (err error) {
	for i := len(dm.delegates) - 1; i >= 0; i-- {
		if err = dm.delegates[i].AfterUpdate(ctx, model, diff); err != nil {
			return
		}
	}
	return
}

func (dm *delegate) BeforeDelete(ctx context.Context, model interface{}) (err error) {
	for i := len(dm.delegates) - 1; i >= 0; i-- {
		if err = dm.delegates[i].BeforeDelete(ctx, model); err != nil {
			return
		}
	}
	return
}

func (dm *delegate) AfterDelete(ctx context.Context, model interface{}) (err error) {
	for i := len(dm.delegates) - 1; i >= 0; i-- {
		if err = dm.delegates[i].AfterDelete(ctx, model); err != nil {
			return
		}
	}
	return
}