// Package store implements a synchronous in-memory K/V store
// fronted by an HTTP server.
package store

import (
	"io"
	"net/http"
	"sync"
)

type Map struct {
	m sync.Map
}

func New(from map[string]string) *Map {
	var m Map
	for k, v := range from {
		m.Set(k, v)
	}
	return &m
}

func (m *Map) Get(k string) (string, bool) {
	r, ok := m.m.Load(k)
	return r.(string), ok
}

func (m *Map) Set(k, v string) {
	m.m.Store(k, v)
}

func (m *Map) Delete(k string) {
	m.m.Delete(k)
}

func (m *Map) Router() http.Handler {
	r := http.NewServeMux()
	r.HandleFunc("GET /{key}", m.get)
	r.HandleFunc("PUT /{key}", m.set)
	r.HandleFunc("POST /{key}", m.set)
	r.HandleFunc("DELETE /{key}", m.delete)
	return r
}

func (m *Map) get(w http.ResponseWriter, r *http.Request) {
	k := r.PathValue("key")
	v, ok := m.Get(k)
	if !ok {
		http.Error(w, "not found", http.StatusNotFound)
	}
	io.WriteString(w, v)
}

func (m *Map) set(w http.ResponseWriter, r *http.Request) {
	k := r.PathValue("key")
	b, err := io.ReadAll(r.Body)
	if err != nil {
		http.Error(w, err.Error(), http.StatusBadRequest)
	}
	m.Set(k, string(b))
	w.WriteHeader(http.StatusNoContent)
}

func (m *Map) delete(w http.ResponseWriter, r *http.Request) {
	k := r.PathValue("key")
	m.Delete(k)
	w.WriteHeader(http.StatusNoContent)
}