package server

import (
	"bytes"
	"fmt"
	"net/http"
	"strconv"

	"golang.org/x/net/context"

	"github.com/Sirupsen/logrus"
	"github.com/drone/drone/bus"
	"github.com/drone/drone/model"
	"github.com/drone/drone/queue"
	"github.com/drone/drone/remote"
	"github.com/drone/drone/store"
	"github.com/drone/mq/stomp"
	"github.com/gorilla/websocket"
)

//
// // Pull is a long request that polls and attemts to pull work off the queue stack.
// func Pull(c *gin.Context) {
// 	logrus.Debugf("Agent %s connected.", c.ClientIP())
//
// 	w := queue.PullClose(c, c.Writer)
// 	if w == nil {
// 		logrus.Debugf("Agent %s could not pull work.", c.ClientIP())
// 	} else {
//
// 		// setup the channel to stream logs
// 		if err := stream.Create(c, stream.ToKey(w.Job.ID)); err != nil {
// 			logrus.Errorf("Unable to create stream. %s", err)
// 		}
//
// 		c.JSON(202, w)
//
// 		logrus.Debugf("Agent %s assigned work. %s/%s#%d.%d",
// 			c.ClientIP(),
// 			w.Repo.Owner,
// 			w.Repo.Name,
// 			w.Build.Number,
// 			w.Job.Number,
// 		)
// 	}
// }
//
// // Wait is a long request that polls and waits for cancelled build requests.
// func Wait(c *gin.Context) {
// 	id, err := strconv.ParseInt(c.Param("id"), 10, 64)
// 	if err != nil {
// 		c.String(500, "Invalid input. %s", err)
// 		return
// 	}
//
// 	eventc := make(chan *bus.Event, 1)
//
// 	bus.Subscribe(c, eventc)
// 	defer bus.Unsubscribe(c, eventc)
//
// 	for {
// 		select {
// 		case event := <-eventc:
// 			if event.Job.ID == id && event.Type == bus.Cancelled {
// 				c.JSON(200, event.Job)
// 				return
// 			}
// 		case <-c.Writer.CloseNotify():
// 			return
// 		}
// 	}
// }
//
// // Update handles build updates from the agent and persists to the database.
// func Update(c *gin.Context) {
// 	work := &queue.Work{}
// 	if err := c.BindJSON(work); err != nil {
// 		logrus.Errorf("Invalid input. %s", err)
// 		return
// 	}
//
// 	// TODO(bradrydzewski) it is really annoying that we have to do this lookup
// 	// and I'd prefer not to. The reason we do this is because the Build and Job
// 	// have fields that aren't serialized to json and would be reset to their
// 	// empty values if we just saved what was coming in the http.Request body.
// 	build, err := store.GetBuild(c, work.Build.ID)
// 	if err != nil {
// 		c.String(404, "Unable to find build. %s", err)
// 		return
// 	}
// 	job, err := store.GetJob(c, work.Job.ID)
// 	if err != nil {
// 		c.String(404, "Unable to find job. %s", err)
// 		return
// 	}
// 	build.Started = work.Build.Started
// 	build.Finished = work.Build.Finished
// 	build.Status = work.Build.Status
// 	job.Started = work.Job.Started
// 	job.Finished = work.Job.Finished
// 	job.Status = work.Job.Status
// 	job.ExitCode = work.Job.ExitCode
// 	job.Error = work.Job.Error
//
// 	if build.Status == model.StatusPending {
// 		build.Started = work.Job.Started
// 		build.Status = model.StatusRunning
// 		store.UpdateBuild(c, build)
// 	}
//
// 	// if job.Status == model.StatusRunning {
// 	// 	err := stream.Create(c, stream.ToKey(job.ID))
// 	// 	if err != nil {
// 	// 		logrus.Errorf("Unable to create stream. %s", err)
// 	// 	}
// 	// }
//
// 	ok, err := store.UpdateBuildJob(c, build, job)
// 	if err != nil {
// 		c.String(500, "Unable to update job. %s", err)
// 		return
// 	}
//
// 	if ok && build.Status != model.StatusRunning {
// 		// get the user because we transfer the user form the server to agent
// 		// and back we lose the token which does not get serialized to json.
// 		user, err := store.GetUser(c, work.User.ID)
// 		if err != nil {
// 			c.String(500, "Unable to find user. %s", err)
// 			return
// 		}
// 		remote.Status(c, user, work.Repo, build,
// 			fmt.Sprintf("%s/%s/%d", work.System.Link, work.Repo.FullName, work.Build.Number))
// 	}
//
// 	if build.Status == model.StatusRunning {
// 		bus.Publish(c, bus.NewEvent(bus.Started, work.Repo, build, job))
// 	} else {
// 		bus.Publish(c, bus.NewEvent(bus.Finished, work.Repo, build, job))
// 	}
//
// 	c.JSON(200, work)
// }
//
// // Stream streams the logs to disk or memory for broadcasing to listeners. Once
// // the stream is closed it is moved to permanent storage in the database.
// func Stream(c *gin.Context) {
// 	id, err := strconv.ParseInt(c.Param("id"), 10, 64)
// 	if err != nil {
// 		c.String(500, "Invalid input. %s", err)
// 		return
// 	}
//
// 	key := c.Param("id")
// 	logrus.Infof("Agent %s creating stream %s.", c.ClientIP(), key)
//
// 	wc, err := stream.Writer(c, key)
// 	if err != nil {
// 		c.String(500, "Failed to create stream writer. %s", err)
// 		return
// 	}
//
// 	defer func() {
// 		wc.Close()
// 		stream.Delete(c, key)
// 	}()
//
// 	io.Copy(wc, c.Request.Body)
//
// 	rc, err := stream.Reader(c, key)
// 	if err != nil {
// 		c.String(500, "Failed to create stream reader. %s", err)
// 		return
// 	}
//
// 	wg := sync.WaitGroup{}
// 	wg.Add(1)
//
// 	go func() {
// 		defer recover()
// 		store.WriteLog(c, &model.Job{ID: id}, rc)
// 		wg.Done()
// 	}()
//
// 	wc.Close()
// 	wg.Wait()
// 	c.String(200, "")
//
// 	logrus.Debugf("Agent %s wrote stream to database", c.ClientIP())
// }
//
// func Ping(c *gin.Context) {
// 	agent, err := store.GetAgentAddr(c, c.ClientIP())
// 	if err == nil {
// 		agent.Updated = time.Now().Unix()
// 		err = store.UpdateAgent(c, agent)
// 	} else {
// 		err = store.CreateAgent(c, &model.Agent{
// 			Address:  c.ClientIP(),
// 			Platform: "linux/amd64",
// 			Capacity: 2,
// 			Created:  time.Now().Unix(),
// 			Updated:  time.Now().Unix(),
// 		})
// 	}
// 	if err != nil {
// 		logrus.Errorf("Unable to register agent. %s", err.Error())
// 	}
// 	c.String(200, "PONG")
// }

//
//
// Below are alternate implementations for the Queue that use websockets.
//
//
//
// // PostLogs handles an http request from the agent to post build logs. These
// // logs are posted at the end of the build process.
// func PostLogs(c *gin.Context) {
// 	id, _ := strconv.ParseInt(c.Param("id"), 10, 64)
// 	job, err := store.GetJob(c, id)
// 	if err != nil {
// 		c.String(404, "Cannot upload logs. %s", err)
// 		return
// 	}
// 	if err := store.WriteLog(c, job, c.Request.Body); err != nil {
// 		c.String(500, "Cannot persist logs", err)
// 		return
// 	}
// 	c.String(200, "")
// }
//
// // WriteLogs handles an http request from the agent to stream build logs from
// // the agent to the server to enable real time streamings to the client.
// func WriteLogs(c *gin.Context) {
// 	id, err := strconv.ParseInt(c.Param("id"), 10, 64)
// 	if err != nil {
// 		c.String(500, "Invalid input. %s", err)
// 		return
// 	}
//
// 	conn, err := upgrader.Upgrade(c.Writer, c.Request, nil)
// 	if err != nil {
// 		c.String(500, "Cannot upgrade to websocket. %s", err)
// 		return
// 	}
// 	defer conn.Close()
//
// 	wc, err := stream.Writer(c, stream.ToKey(id))
// 	if err != nil {
// 		c.String(500, "Cannot create stream writer. %s", err)
// 		return
// 	}
// 	defer func() {
// 		wc.Close()
// 		stream.Delete(c, stream.ToKey(id))
// 	}()
//
// 	var msg []byte
// 	for {
// 		_, msg, err = conn.ReadMessage()
// 		if err != nil {
// 			break
// 		}
// 		wc.Write(msg)
// 		wc.Write(newline)
// 	}
//
// 	if err != nil && err != io.EOF {
// 		c.String(500, "Error reading logs. %s", err)
// 		return
// 	}
// 	//
// 	// rc, err := stream.Reader(c, stream.ToKey(id))
// 	// if err != nil {
// 	// 	c.String(500, "Failed to create stream reader. %s", err)
// 	// 	return
// 	// }
// 	//
// 	// wg := sync.WaitGroup{}
// 	// wg.Add(1)
// 	//
// 	// go func() {
// 	// 	defer recover()
// 	// 	store.WriteLog(c, &model.Job{ID: id}, rc)
// 	// 	wg.Done()
// 	// }()
// 	//
// 	// wc.Close()
// 	// wg.Wait()
//
// }

// newline defines a newline constant to separate lines in the build output
var newline = []byte{'\n'}

// upgrader defines the default behavior for upgrading the websocket.
var upgrader = websocket.Upgrader{
	ReadBufferSize:  1024,
	WriteBufferSize: 1024,
	CheckOrigin: func(r *http.Request) bool {
		return true
	},
}

// HandleUpdate handles build updates from the agent and persists to the database.
func HandleUpdate(c context.Context, message *stomp.Message) {
	defer func() {
		message.Release()
		if r := recover(); r != nil {
			err := r.(error)
			logrus.Errorf("Panic recover: broker update handler: %s", err)
		}
	}()

	work := new(queue.Work)
	if err := message.Unmarshal(work); err != nil {
		logrus.Errorf("Invalid input. %s", err)
		return
	}

	// TODO(bradrydzewski) it is really annoying that we have to do this lookup
	// and I'd prefer not to. The reason we do this is because the Build and Job
	// have fields that aren't serialized to json and would be reset to their
	// empty values if we just saved what was coming in the http.Request body.
	build, err := store.GetBuild(c, work.Build.ID)
	if err != nil {
		logrus.Errorf("Unable to find build. %s", err)
		return
	}
	job, err := store.GetJob(c, work.Job.ID)
	if err != nil {
		logrus.Errorf("Unable to find job. %s", err)
		return
	}
	build.Started = work.Build.Started
	build.Finished = work.Build.Finished
	build.Status = work.Build.Status
	job.Started = work.Job.Started
	job.Finished = work.Job.Finished
	job.Status = work.Job.Status
	job.ExitCode = work.Job.ExitCode
	job.Error = work.Job.Error

	if build.Status == model.StatusPending {
		build.Started = work.Job.Started
		build.Status = model.StatusRunning
		store.UpdateBuild(c, build)
	}

	// if job.Status == model.StatusRunning {
	// 	err := stream.Create(c, stream.ToKey(job.ID))
	// 	if err != nil {
	// 		logrus.Errorf("Unable to create stream. %s", err)
	// 	}
	// }

	ok, err := store.UpdateBuildJob(c, build, job)
	if err != nil {
		logrus.Errorf("Unable to update job. %s", err)
		return
	}

	if ok {
		// get the user because we transfer the user form the server to agent
		// and back we lose the token which does not get serialized to json.
		user, uerr := store.GetUser(c, work.User.ID)
		if uerr != nil {
			logrus.Errorf("Unable to find user. %s", err)
			return
		}
		remote.Status(c, user, work.Repo, build,
			fmt.Sprintf("%s/%s/%d", work.System.Link, work.Repo.FullName, work.Build.Number))
	}

	client := stomp.MustFromContext(c)
	err = client.SendJSON("/topic/events", bus.Event{
		Type:  bus.Started,
		Repo:  *work.Repo,
		Build: *build,
		Job:   *job,
	},
		stomp.WithHeader("repo", work.Repo.FullName),
		stomp.WithHeader("private", strconv.FormatBool(work.Repo.IsPrivate)),
	)
	if err != nil {
		logrus.Errorf("Unable to publish to /topic/events. %s", err)
	}

	if job.Status == model.StatusRunning {
		return
	}

	var buf bytes.Buffer
	var sub []byte

	done := make(chan bool)
	dest := fmt.Sprintf("/topic/logs.%d", job.ID)
	sub, err = client.Subscribe(dest, stomp.HandlerFunc(func(m *stomp.Message) {
		defer m.Release()
		if m.Header.GetBool("eof") {
			done <- true
			return
		}
		buf.Write(m.Body)
		buf.WriteByte('\n')
	}))

	if err != nil {
		logrus.Errorf("Unable to read logs from broker. %s", err)
		return
	}
	<-done

	if err := store.WriteLog(c, job, &buf); err != nil {
		logrus.Errorf("Unable to write logs to store. %s", err)
		return
	}

	client.Unsubscribe(sub)
	client.Send(dest, []byte{}, stomp.WithRetain("remove"))
}