package main

import (
	"encoding/json"
	"errors"
	"io"
	"io/ioutil"
	"local/router"
	"net/http"
	"os"
	"path"
	"strings"

	"github.com/google/uuid"
)

type Server struct {
	router *router.Router
	root   string
}

func NewServer(root string) *Server {
	return &Server{
		router: router.New(),
		root:   root,
	}
}

func (server *Server) Routes() error {
	wildcard := func(s string) string {
		return strings.TrimSuffix(s, "/") + "/" + router.Wildcard
	}
	wildcards := func(s string) string {
		return wildcard(wildcard(s))
	}
	_ = wildcards
	for path, handler := range map[string]func(http.ResponseWriter, *http.Request) error{
		"/":                        server.rootHandler,
		"/api/v0/tree":             server.apiV0TreeHandler,
		"/api/v0/media":            server.apiV0MediaHandler,
		wildcard("/api/v0/media"):  server.apiV0MediaIDHandler,
		"/api/v0/files":            server.apiV0FilesHandler,
		wildcard("/api/v0/files/"): server.apiV0FilesIDHandler,
		"/api/v0/search":           server.apiV0SearchHandler,
	} {
		if err := server.router.Add(path, server.tryCatchHttpHandler(handler)); err != nil {
			return err
		}
	}
	return nil
}

func (server *Server) ServeHTTP(w http.ResponseWriter, r *http.Request) {
	server.router.ServeHTTP(w, r)
}

func (server *Server) tryCatchHttpHandler(handler func(http.ResponseWriter, *http.Request) error) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		if err := handler(w, r); err != nil {
			http.Error(w, err.Error(), http.StatusInternalServerError)
		}
	}
}

func (server *Server) apiV0TreeHandler(w http.ResponseWriter, r *http.Request) error {
	tree := server.tree()
	branches, err := tree.Get()
	if err != nil {
		return err
	}
	return json.NewEncoder(w).Encode(branches)
}

func ensureAndWrite(p string, b []byte) error {
	if err := os.MkdirAll(path.Dir(p), os.ModePerm); err != nil {
		return err
	}
	return ioutil.WriteFile(p, b, os.ModePerm)
}

func (server *Server) apiV0MediaHandler(w http.ResponseWriter, r *http.Request) error {
	id := uuid.New().String()
	filePath := server.diskMediaPath(id)
	if err := server.postContentHandler(filePath, w, r); err != nil {
		return err
	}
	return json.NewEncoder(w).Encode(map[string]map[string]string{
		"data": map[string]string{
			"filePath": path.Join("/api/v0/media", id),
		},
	})
}

func (server *Server) apiV0MediaIDHandler(w http.ResponseWriter, r *http.Request) error {
	switch r.Method {
	case http.MethodGet:
		return server.apiV0MediaIDGetHandler(w, r)
	case http.MethodDelete:
		return server.apiV0MediaIDDelHandler(w, r)
	}
	http.NotFound(w, r)
	return nil
}

func (server *Server) apiV0MediaIDDelHandler(w http.ResponseWriter, r *http.Request) error {
	id := path.Base(r.URL.Path)
	os.Remove(server.diskMediaPath(id))
	return nil
}

func (server *Server) apiV0MediaIDGetHandler(w http.ResponseWriter, r *http.Request) error {
	id := path.Base(r.URL.Path)
	return server.getContentHandler(server.diskMediaPath(id), w, r)
}

func (server *Server) apiV0FilesHandler(w http.ResponseWriter, r *http.Request) error {
	return errors.New("not impl: apiV0FilesHandler")
}

func (server *Server) getContentHandler(filePath string, w http.ResponseWriter, r *http.Request) error {
	if r.Method != http.MethodGet {
		return errors.New("not found")
	}
	f, err := os.Open(filePath)
	if os.IsNotExist(err) {
		http.NotFound(w, r)
		return nil
	}
	if err != nil {
		return err
	}
	defer f.Close()
	io.Copy(w, f)
	return nil
}

func (server *Server) postContentHandler(filePath string, w http.ResponseWriter, r *http.Request) error {
	if r.Method != http.MethodPost {
		return errors.New("not found")
	}
	defer r.Body.Close()
	b, err := ioutil.ReadAll(r.Body)
	if err != nil {
		return err
	}
	return ensureAndWrite(filePath, b)
}

func (server *Server) apiV0FilesIDHandler(w http.ResponseWriter, r *http.Request) error {
	return errors.New("not impl" + r.URL.Path)
}

func (server *Server) apiV0SearchHandler(w http.ResponseWriter, r *http.Request) error {
	return errors.New("not impl" + r.URL.Path)
}

func (server *Server) rootHandler(w http.ResponseWriter, r *http.Request) error {
	return server.getContentHandler(path.Join(server.root, "index.html"), w, r)
}

func (server *Server) tree() *Tree {
	return NewTree(path.Join(server.root, "tree.yaml"))
}

func (server *Server) diskMediaPath(id string) string {
	return path.Join(server.root, "media", id)
}