package csstool

type matcher interface {

Remove([]string) bool

}

// EmptyMatcher this keeps all elements, or rather, doesn't remove anything

type EmptyMatcher struct{}

// Remove always returns false (i.e. keep everything)

func (em *EmptyMatcher) Remove([]string) bool {

return false

}

// TagMatcher determines if a given CSS identifier should be kept or removed

// doesn't need to be public

type TagMatcher struct {

tags map[string]bool

}

// NewTagMatcher creates an initialized TagMatch object

func NewTagMatcher(tags []string) *TagMatcher {

tagmap := make(map[string]bool, len(tags))

tagmap[""] = true

tagmap["*"] = true

tagmap[":root"] = true

tagmap[":first-child"] = true

tagmap["::after"] = true

tagmap["::before"] = true

for _, tag := range tags {

tagmap[tag] = true

}

return &TagMatcher{tags: tagmap}

}

// Remove returns true if tag is to be dropped

func (tm *TagMatcher) Remove(selectors []string) bool {

for _, selector := range selectors {

if !tm.tags[selector] {

return true

}

}

return false //i.e. keep

}

// AddSelector adds a selector to save

func (tm *TagMatcher) AddSelector(key string) {

tm.tags[key] = true

}

// RemoveSelector deletes a selector to save

func (tm *TagMatcher) RemoveSelector(key string) {

delete(tm.tags, key)

}