package compat

import (
	"bytes"
	"encoding/base64"
	"encoding/json"
	"fmt"
	"net/http"
	"os"
	"time"

	"github.com/containers/podman/v2/libpod"
	"github.com/containers/podman/v2/libpod/define"
	"github.com/containers/podman/v2/pkg/api/handlers/utils"
	"github.com/containers/podman/v2/pkg/copy"
	"github.com/gorilla/schema"
	"github.com/pkg/errors"
)

func Archive(w http.ResponseWriter, r *http.Request) {
	decoder := r.Context().Value("decoder").(*schema.Decoder)
	runtime := r.Context().Value("runtime").(*libpod.Runtime)

	switch r.Method {
	case http.MethodPut:
		handlePut(w, r, decoder, runtime)
	case http.MethodHead, http.MethodGet:
		handleHeadAndGet(w, r, decoder, runtime)
	default:
		utils.Error(w, fmt.Sprintf("unsupported method: %v", r.Method), http.StatusNotImplemented, errors.New(fmt.Sprintf("unsupported method: %v", r.Method)))
	}
}

func handleHeadAndGet(w http.ResponseWriter, r *http.Request, decoder *schema.Decoder, runtime *libpod.Runtime) {
	query := struct {
		Path string `schema:"path"`
	}{}

	err := decoder.Decode(&query, r.URL.Query())
	if err != nil {
		utils.Error(w, "Bad Request.", http.StatusBadRequest, errors.Wrap(err, "couldn't decode the query"))
		return
	}

	if query.Path == "" {
		utils.Error(w, "Bad Request.", http.StatusBadRequest, errors.New("missing `path` parameter"))
		return
	}

	containerName := utils.GetName(r)

	ctr, err := runtime.LookupContainer(containerName)
	if errors.Cause(err) == define.ErrNoSuchCtr {
		utils.Error(w, "Not found.", http.StatusNotFound, errors.Wrap(err, "the container doesn't exists"))
		return
	} else if err != nil {
		utils.Error(w, "Something went wrong.", http.StatusInternalServerError, err)
		return
	}

	source, err := copy.CopyItemForContainer(ctr, query.Path, true, true)
	defer source.CleanUp()
	if err != nil {
		utils.Error(w, "Not found.", http.StatusNotFound, errors.Wrapf(err, "error stating container path %q", query.Path))
		return
	}

	// NOTE: Docker always sets the header.
	info, err := source.Stat()
	if err != nil {
		utils.Error(w, "Not found.", http.StatusNotFound, errors.Wrapf(err, "error stating container path %q", query.Path))
		return
	}
	statHeader, err := fileInfoToDockerStats(info)
	if err != nil {
		utils.Error(w, "Something went wrong", http.StatusInternalServerError, err)
		return
	}
	w.Header().Add("X-Docker-Container-Path-Stat", statHeader)

	// Our work is done when the user is interested in the header only.
	if r.Method == http.MethodHead {
		w.WriteHeader(http.StatusOK)
		return
	}

	// Alright, the users wants data from the container.
	destination, err := copy.CopyItemForWriter(w)
	if err != nil {
		utils.Error(w, "Something went wrong", http.StatusInternalServerError, err)
		return
	}

	w.WriteHeader(http.StatusOK)
	if err := copy.Copy(&source, &destination, false); err != nil {
		utils.Error(w, "Something went wrong", http.StatusInternalServerError, err)
		return
	}
}

func fileInfoToDockerStats(info *copy.FileInfo) (string, error) {
	dockerStats := struct {
		Name       string      `json:"name"`
		Size       int64       `json:"size"`
		Mode       os.FileMode `json:"mode"`
		ModTime    time.Time   `json:"mtime"`
		LinkTarget string      `json:"linkTarget"`
	}{
		Name:       info.Name,
		Size:       info.Size,
		Mode:       info.Mode,
		ModTime:    info.ModTime,
		LinkTarget: info.LinkTarget,
	}

	jsonBytes, err := json.Marshal(&dockerStats)
	if err != nil {
		return "", errors.Wrap(err, "failed to serialize file stats")
	}

	buff := bytes.NewBuffer(make([]byte, 0, 128))
	base64encoder := base64.NewEncoder(base64.StdEncoding, buff)

	_, err = base64encoder.Write(jsonBytes)
	if err != nil {
		return "", err
	}

	err = base64encoder.Close()
	if err != nil {
		return "", err
	}

	return buff.String(), nil
}

func handlePut(w http.ResponseWriter, r *http.Request, decoder *schema.Decoder, runtime *libpod.Runtime) {
	query := struct {
		Path string `schema:"path"`
		// TODO handle params below
		NoOverwriteDirNonDir bool `schema:"noOverwriteDirNonDir"`
		CopyUIDGID           bool `schema:"copyUIDGID"`
	}{}

	err := decoder.Decode(&query, r.URL.Query())
	if err != nil {
		utils.Error(w, "Bad Request.", http.StatusBadRequest, errors.Wrap(err, "couldn't decode the query"))
		return
	}

	ctrName := utils.GetName(r)

	ctr, err := runtime.LookupContainer(ctrName)
	if err != nil {
		utils.Error(w, "Not found", http.StatusNotFound, errors.Wrapf(err, "the %s container doesn't exists", ctrName))
		return
	}

	destination, err := copy.CopyItemForContainer(ctr, query.Path, true, false)
	defer destination.CleanUp()
	if err != nil {
		utils.Error(w, "Something went wrong", http.StatusInternalServerError, err)
		return
	}

	source, err := copy.CopyItemForReader(r.Body)
	defer source.CleanUp()
	if err != nil {
		utils.Error(w, "Something went wrong", http.StatusInternalServerError, err)
		return
	}

	w.WriteHeader(http.StatusOK)
	if err := copy.Copy(&source, &destination, false); err != nil {
		utils.Error(w, "Something went wrong", http.StatusInternalServerError, err)
		return
	}
}