package routerx

import "fmt"

type Matcher func(level int) bool

type Route struct {
	Index   int
	Name    string
	Match   Matcher
	Enabled bool
}

type Snapshot struct {
	Index int
	Name  string
	Match Matcher
}

func Normalize(routes []Route) []Snapshot {
	if len(routes) == 0 {
		return nil
	}
	result := make([]Snapshot, 0, len(routes))
	for _, route := range routes {
		if !route.Enabled {
			continue
		}
		name := route.Name
		if name == "" {
			name = fmt.Sprintf("route-%d", route.Index)
		}
		match := route.Match
		if match == nil {
			match = MatchAllLevels()
		}
		result = append(result, Snapshot{
			Index: route.Index,
			Name:  name,
			Match: match,
		})
	}
	return result
}

func MatchAllLevels() Matcher {
	return func(level int) bool {
		_ = level
		return true
	}
}

func MatchLevels(levels ...int) Matcher {
	levelSet := make(map[int]struct{}, len(levels))
	for _, level := range levels {
		levelSet[level] = struct{}{}
	}
	return func(level int) bool {
		_, ok := levelSet[level]
		return ok
	}
}

func MatchAtLeast(minLevel int) Matcher {
	return func(level int) bool {
		return level >= minLevel
	}
}