package mux

import (
	"fmt"
	"net/http"
	"strings"
)

// Resource is a resourceful route provides a mapping between HTTP verbs and URLs and controller actions.
// By convention, each action also maps to particular CRUD operations in a database.
// A single entry in the routing file, such as
// Index route
//
// GET	/resource-name				# index route
//
// GET	/resource-name/new		# create resource page
//
// POST	/resource-name				# create resource post
//
// GET	/resource-name/:id			# view resource
//
// GET	/resource-name/:id/edit		# edit resource
//
// PUT	/resource-name/:id			# update resource
//
// DELETE	/resource-name/:id		# delete resource
type Resource struct {
	mux         *http.ServeMux
	pattern     string
	middlewares []func(http.Handler) http.Handler
}

func suffixIt(str, suffix string) string {
	var p strings.Builder
	p.WriteString(str)
	if !strings.HasSuffix(str, "/") {
		p.WriteString("/")
	}
	p.WriteString(suffix)
	return p.String()
}

// Index is GET /resource-name
func (r *Resource) Index(h http.HandlerFunc) {
	r.handlerFunc(http.MethodGet, r.pattern, h)
}

// New is GET /resource-name/new
func (r *Resource) New(h http.HandlerFunc) {
	r.handlerFunc(http.MethodGet, suffixIt(r.pattern, "new"), h)
}

// Create is POST /resource-name
func (r *Resource) Create(h http.HandlerFunc) {
	r.handlerFunc(http.MethodPost, r.pattern, h)
}

// Show is GET /resource-name/:id
func (r *Resource) Show(h http.HandlerFunc) {
	r.handlerFunc(http.MethodGet, suffixIt(r.pattern, "{id}"), h)
}

// Update is PUT /resource-name/:id
func (r *Resource) Update(h http.HandlerFunc) {
	r.handlerFunc(http.MethodPut, suffixIt(r.pattern, "{id}"), h)
}

// PartialUpdate is PATCH /resource-name/:id
func (r *Resource) PartialUpdate(h http.HandlerFunc) {
	r.handlerFunc(http.MethodPatch, suffixIt(r.pattern, "{id}"), h)
}

func (r *Resource) Destroy(h http.HandlerFunc) {
	r.handlerFunc(http.MethodDelete, suffixIt(r.pattern, "{id}"), h)
}

// handlerFunc registers the handler function for the given pattern.
// If the given pattern conflicts, with one that is already registered, HandleFunc
// panics.
func (r *Resource) handlerFunc(method, pattern string, h http.HandlerFunc) {
	if r == nil {
		panic("serve: func handlerFunc() was called on nil")
	}

	if r.mux == nil {
		panic("serve: router mux is nil")
	}

	path := fmt.Sprintf("%s %s", method, pattern)
	r.mux.Handle(path, stack(r.middlewares, h))
}

// Use will register middleware(s) on Router stack.
func (r *Resource) Use(middlewares ...func(http.Handler) http.Handler) {
	if r == nil {
		panic("serve: func Use was called on nil")
	}
	r.middlewares = append(r.middlewares, middlewares...)
}