package pkg

import (
	b64 "encoding/base64"
	"encoding/json"
	"fmt"
	"golang.org/x/exp/slices"
	"io"
	"log"
	"net/http"
	"strings"

	nomad "github.com/hashicorp/nomad/api"
)

type HookHandler struct {
	Config  *Config
	Cluster *Cluster
}

type BuildHandler struct {
	Config  *Config
	Cluster *Cluster
}

func (h HookHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
	if r.Method != http.MethodPost {
		http.Error(w, "Hook only support POST requests", http.StatusBadRequest)
		return
	}

	q := r.URL.Query()
	maybeToken, ok := q["token"]
	if !ok || len(maybeToken) < 1 {
		http.Error(w, "Missing query parameter 'token'. Try adding '?token=xxx'", http.StatusBadRequest)
		return
	}
	token := maybeToken[0]
	flavor := "default"

	var notification GiteaNotification
	dec := json.NewDecoder(r.Body)
	if err := dec.Decode(&notification); err != nil {
		http.Error(w, "Can't parse your request JSON", http.StatusBadRequest)
		return
	}
	notifInfo := notifSummary(&notification)

	log.Printf("Received gitea notification for %s\n", notifInfo)

	// Fetch our repo descriptor
	kv := h.Cluster.Consul.KV()
	encodedRepoUrl := b64.StdEncoding.EncodeToString([]byte(notification.Repository.CloneUrl))
	key := "albatros/" + encodedRepoUrl
	log.Printf("Fetching key %s for %s\n", key, notifInfo)
	pair, _, err := kv.Get(key, nil)
	if err != nil {
		http.Error(w, "Can't fetch the repo descriptor in Consul", http.StatusInternalServerError)
		log.Printf("Job error for %s, can't fetch repo descriptor in consul: %+v\n", notifInfo, err)
		return
	}
	if pair == nil || pair.Value == nil {
		http.Error(w, "You must declare %s in Consul in order to build it", http.StatusForbidden)
		return
	}
	// Parse our repo descriptor
	var repoDesc ConsulSecret
	if err = json.Unmarshal(pair.Value, &repoDesc); err != nil {
		http.Error(w, "Can't decode your Consul configuration for this repo", http.StatusInternalServerError)
		log.Printf("Job error for %s, can't unmarshal the Consul descriptor: %+v\n", notifInfo, err)
		return
	}
	// Check token
	if repoDesc.Hook.Token != token {
		http.Error(w, "Your albatros token does not match the one declared in Consul", http.StatusForbidden)
		return
	}

	// Build job parameters for Nomad
	meta := map[string]string{
		"REPO_URL": notification.Repository.CloneUrl,
		"COMMIT":   notification.After,
		"FLAVOR":   flavor,
		// @FIXME: this code is not correct, this is a hack
		"BRANCH": strings.ReplaceAll(notification.Ref, "refs/heads/", ""),
	}

	// Check sender
	payload := []byte{}
	if slices.Contains(repoDesc.Trusted.Senders, notification.Sender.Username) {
		log.Printf("Trusted build of %s as %s in the list of allowed senders, inject secrets\n", notifInfo, notification.Sender.Username)
		// Write payload
		payload = []byte(repoDesc.Inject)
	}

	jobs := h.Cluster.Nomad.Jobs()
	dres, _, err := jobs.Dispatch("builder", meta, payload, "albatros", &nomad.WriteOptions{})
	if err != nil {
		http.Error(w, "Can't submit your job to Nomad", http.StatusInternalServerError)
	}
	log.Printf("Created job %s for %s\n", dres.DispatchedJobID, notifInfo)

	// Start a lifecycle observer to update gitea status
	j := Job{
		Cluster:      h.Cluster,
		Config:       h.Config,
		Notification: &notification,
		Dispatch:     dres,
		Creds:        &repoDesc.Gitea,
		Flavor:       flavor,
	}
	go j.follow()

	io.WriteString(w, dres.DispatchedJobID)
}

func (b BuildHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
	q := r.URL.Query()
	jobID, ok := q["job"]
	if !ok || len(jobID) < 1 {
		http.Error(w, "Missing query parameter 'job'. Try adding '?job=xxx'", http.StatusBadRequest)
		return
	}

	logType, ok := q["log"]
	log.Printf("Follow logs for %s\n", jobID)
	if !ok || len(logType) < 1 || !(logType[0] == "stdout" || logType[0] == "stderr") {
		http.Error(w, "Missing or wrong query parameter 'log'.\nTry adding '?log=stdout' or '?log=stderr'", http.StatusBadRequest)
		return
	}
	logFilter := logType[0]

	jobs := b.Cluster.Nomad.Jobs()
	allocList, _, err := jobs.Allocations(jobID[0], true, &nomad.QueryOptions{})
	if err != nil {
		http.Error(w, "Unable to fetch your job on Nomad. Might be garbage collected.", http.StatusInternalServerError)
		return
	}
	if len(allocList) < 1 {
		http.Error(w, "Job does not contain at least 1 allocation, can't display logs. Job might be garbage collected. ", http.StatusNotFound)
		return
	}

	myAllocStub := allocList[0]

	allocations := b.Cluster.Nomad.Allocations()
	myAlloc, _, err := allocations.Info(myAllocStub.ID, &nomad.QueryOptions{})
	if err != nil {
		http.Error(w, "Allocation does not exist anymore. Allocation might be garbage collected", http.StatusNotFound)
		return
	}
	log.Printf("Selected alloc %s for job %s\n", myAlloc.ID, jobID)

	allocFS := b.Cluster.Nomad.AllocFS()
	scancel := make(chan struct{})
	sframe, serr := allocFS.Logs(myAlloc, true, "executor", logFilter, "start", 0, scancel, &nomad.QueryOptions{})

	// stream logs to client's browser
	io.WriteString(w, fmt.Sprintf("--- Streaming logs for %s, job can take some times to start, be patient ---\n", jobID))
build_loop:
	for {
		select {
		case <-r.Context().Done():
			// client disconnect, cleaning
			break build_loop
		case nomadErr := <-serr:
			// an error occured in nomad, inform user and clean
			_, _ = io.WriteString(w, fmt.Sprintf("\n--- Broken stream: %+v ---\n", nomadErr))
			break build_loop
		case chunk := <-sframe:
			// we get some data from nomad, send it to the client
			for i := 0; i < len(chunk.Data); {
				written, err := w.Write(chunk.Data[i:])
				w.(http.Flusher).Flush() // flush the buffer to send it right now
				i += written
				if err == io.EOF {
					_, _ = io.WriteString(w, "\n--- End of file :-) ---\n")
					break build_loop
				} else if err != nil {
					_, _ = io.WriteString(w, fmt.Sprintf("\n--- Broken stream: %+v ---\n", err))
					break build_loop
				}
			}
		}
	}

	log.Printf("Connection closed, cleaning listeners for %s\n", jobID)
	scancel <- struct{}{}
}