/*
 * Minimalist Object Storage, (C) 2014 Minio, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package api

import (
	"log"
	"net/http"

	"bytes"
	"encoding/json"
	router "github.com/gorilla/mux"
	"github.com/minio-io/minio/pkg/api/config"
	"github.com/minio-io/minio/pkg/api/quota"
	"github.com/minio-io/minio/pkg/iodine"
	"github.com/minio-io/minio/pkg/storage/drivers"
	"io"
	"os"
	"time"
)

// private use
type minioAPI struct {
	domain string
	driver drivers.Driver
}

// Path based routing
func pathMux(api minioAPI, mux *router.Router) *router.Router {
	mux.HandleFunc("/", api.listBucketsHandler).Methods("GET")
	mux.HandleFunc("/{bucket}", api.listObjectsHandler).Methods("GET")
	mux.HandleFunc("/{bucket}", api.putBucketHandler).Methods("PUT")
	mux.HandleFunc("/{bucket}", api.headBucketHandler).Methods("HEAD")
	mux.HandleFunc("/{bucket}/{object:.*}", api.getObjectHandler).Methods("GET")
	mux.HandleFunc("/{bucket}/{object:.*}", api.headObjectHandler).Methods("HEAD")
	mux.HandleFunc("/{bucket}/{object:.*}", api.putObjectHandler).Methods("PUT")

	return mux
}

// Domain based routing
func domainMux(api minioAPI, mux *router.Router) *router.Router {
	mux.HandleFunc("/",
		api.listObjectsHandler).Host("{bucket}" + "." + api.domain).Methods("GET")
	mux.HandleFunc("/{object:.*}",
		api.getObjectHandler).Host("{bucket}" + "." + api.domain).Methods("GET")
	mux.HandleFunc("/{object:.*}",
		api.headObjectHandler).Host("{bucket}" + "." + api.domain).Methods("HEAD")
	mux.HandleFunc("/{object:.*}",
		api.putObjectHandler).Host("{bucket}" + "." + api.domain).Methods("PUT")
	mux.HandleFunc("/", api.listBucketsHandler).Methods("GET")
	mux.HandleFunc("/{bucket}", api.putBucketHandler).Methods("PUT")
	mux.HandleFunc("/{bucket}", api.headBucketHandler).Methods("HEAD")

	return mux
}

// Get proper router based on domain availability
func getMux(api minioAPI, mux *router.Router) *router.Router {
	switch true {
	case api.domain == "":
		return pathMux(api, mux)
	case api.domain != "":
		s := mux.Host(api.domain).Subrouter()
		return domainMux(api, s)
	}
	return nil
}

// HTTPHandler - http wrapper handler
func HTTPHandler(domain string, driver drivers.Driver) http.Handler {
	var mux *router.Router
	var api = minioAPI{}
	api.driver = driver
	api.domain = domain

	r := router.NewRouter()
	mux = getMux(api, r)

	var conf = config.Config{}
	if err := conf.SetupConfig(); err != nil {
		log.Fatal(iodine.New(err, map[string]string{"domain": domain}))
	}
	h := timeValidityHandler(mux)
	h = ignoreResourcesHandler(h)
	h = validateRequestHandler(conf, h)
	//	h = quota.BandwidthCap(h, 25*1024*1024, time.Duration(30*time.Minute))
	//	h = quota.BandwidthCap(h, 100*1024*1024, time.Duration(24*time.Hour))
	//	h = quota.RequestLimit(h, 100, time.Duration(30*time.Minute))
	//	h = quota.RequestLimit(h, 1000, time.Duration(24*time.Hour))
	h = quota.ConnectionLimit(h, 5)
	h = LogHandler(h)
	return h
}

type logHandler struct {
	http.Handler
	Logger chan<- string
}

// LogMessage is a serializable json log message
type LogMessage struct {
	Request         *http.Request
	StartTime       time.Time
	Duration        time.Duration
	Status          int
	ResponseHeaders http.Header
}

// LogWriter is used to capture status for log messages
type LogWriter struct {
	http.ResponseWriter
	LogMessage *LogMessage
}

// WriteHeader writes headers and stores status in LogMessage
func (w *LogWriter) WriteHeader(status int) {
	w.LogMessage.Status = status
	w.ResponseWriter.WriteHeader(status)
	w.ResponseWriter.Header()
}

func (h *logHandler) ServeHTTP(w http.ResponseWriter, req *http.Request) {
	logMessage := &LogMessage{
		StartTime: time.Now(),
	}
	logWriter := &LogWriter{ResponseWriter: w, LogMessage: logMessage}
	h.Handler.ServeHTTP(logWriter, req)
	logMessage.ResponseHeaders = w.Header()
	logMessage.Request = req
	logMessage.Duration = time.Now().Sub(logMessage.StartTime)
	js, _ := json.Marshal(logMessage)
	h.Logger <- string(js)
}

// LogHandler logs requests
func LogHandler(h http.Handler) http.Handler {
	logger, _ := FileLogger("access.log")
	return &logHandler{Handler: h, Logger: logger}
}

// FileLogger returns a channel that is used to write to the logger
func FileLogger(filename string) (chan<- string, error) {
	ch := make(chan string)
	file, err := os.OpenFile(filename, os.O_CREATE|os.O_APPEND|os.O_WRONLY, 0600)
	if err != nil {
		return nil, iodine.New(err, map[string]string{"logfile": filename})
	}
	go func() {
		for message := range ch {
			if _, err := io.Copy(file, bytes.NewBufferString(message+"\n")); err != nil {
				log.Println(iodine.New(err, nil))
			}
		}
	}()
	return ch, nil
}