package httpreverse

import "strings"

type Router struct {
	Hostname string
	Leaf     *Leaf
	leafMap  map[string]*Leaf
}

type Leaf struct {
	Name     string
	Val      any
	Last     *Leaf
	Next     map[string]*Leaf
	FullPath string
}

func NewRouter(hostname string) *Router {
	return &Router{
		Hostname: hostname,
		Leaf: &Leaf{
			Name:     "/",
			Next:     make(map[string]*Leaf),
			FullPath: "/",
		},
		leafMap: make(map[string]*Leaf),
	}
}

func (r *Router) AddLeaf(path string, val any) {
	if r.Leaf == nil {
		r.Leaf = &Leaf{
			Name:     "/",
			Next:     make(map[string]*Leaf),
			FullPath: "/",
		}
	}
	if r.leafMap == nil {
		r.leafMap = make(map[string]*Leaf)
		r.leafMap["/"] = r.Leaf
	}
	names := strings.Split(path, "/")
	leaf := r.Leaf
	for _, name := range names {
		if name == "" {
			continue
		}
		if leaf.Next[name] == nil {
			fullPath := leaf.FullPath + "/" + name
			if leaf.FullPath == "/" {
				fullPath = "/" + name
			}
			leaf.Next[name] = &Leaf{
				Name:     name,
				Next:     make(map[string]*Leaf),
				FullPath: fullPath,
			}
			r.leafMap[fullPath] = leaf.Next[name]
		}
		leaf = leaf.Next[name]
	}
	leaf.Val = val
}

func (r *Router) GetLeaf(path string) *Leaf {
	return r.leafMap[path]
}

func (r *Router) NearestLeaf(path string) *Leaf {
	if path == "/" {
		return r.Leaf
	}
	if leaf, ok := r.leafMap[path]; ok {
		return leaf
	}
	parts := strings.Split(path, "/")
	leaf := r.Leaf
	for _, v := range parts {
		if v == "" {
			continue
		}
		if leaf.Next[v] == nil {
			return leaf
		}
		leaf = leaf.Next[v]
	}
	return leaf
}

func (r *Router) NearestLeafWithVal(path string) *Leaf {
	if path == "/" {
		return r.Leaf
	}
	if leaf, ok := r.leafMap[path]; ok && leaf.Val != nil {
		return leaf
	}
	var lastValue *Leaf
	parts := strings.Split(path, "/")
	leaf := r.Leaf
	if leaf.Val != nil {
		lastValue = leaf
	}
	for _, v := range parts {
		if v == "" {
			continue
		}
		if leaf.Next[v] == nil {
			return lastValue
		}
		leaf = leaf.Next[v]
		if leaf.Val != nil {
			lastValue = leaf
		}
	}
	return lastValue
}