package koji

import (

	"bytes"

	"crypto/md5"

	"encoding/json"

	"fmt"

	"hash/adler32"

	"io"

	"io/ioutil"

	"net/http"

	"net/url"

	"github.com/kolo/xmlrpc"

)

type Koji struct {

	sessionID  int64

	sessionKey string

	callnum    int

	xmlrpc     *xmlrpc.Client

	server     string

}

type BuildExtra struct {

	Image interface{} `json:"image"` // No extra info tracked at build level.

}

type Build struct {

	Name      string     `json:"name"`

	Version   string     `json:"version"`

	Release   string     `json:"release"`

	Source    string     `json:"source"`

	StartTime int64      `json:"start_time"`

	EndTime   int64      `json:"end_time"`

	Extra     BuildExtra `json:"extra"`

}

type Host struct {

	Os   string `json:"os"`

	Arch string `json:"arch"`

}

type ContentGenerator struct {

	Name    string `json:"name"`

	Version string `json:"version"`

}

type Container struct {

	Type string `json:"type"`

	Arch string `json:"arch"`

}

type Tool struct {

	Name    string `json:"name"`

	Version string `json:"version"`

}

type Component struct {

	Type      string  `json:"type"` // must be 'rpm'

	Name      string  `json:"name"`

	Version   string  `json:"version"`

	Release   string  `json:"release"`

	Epoch     *uint64 `json:"epoch"`

	Arch      string  `json:"arch"`

	Sigmd5    string  `json:"sigmd5"`

	Signature *string `json:"signature"`

}

type BuildRoot struct {

	ID               uint64           `json:"id"`

	Host             Host             `json:"host"`

	ContentGenerator ContentGenerator `json:"content_generator"`

	Container        Container        `json:"container"`

	Tools            []Tool           `json:"tools"`

	Components       []Component      `json:"components"`

}

type OutputExtraImageInfo struct {

	// TODO: Ideally this is where the pipeline would be passed.

	Arch string `json:"arch"` // TODO: why?

}

type OutputExtra struct {

	Image OutputExtraImageInfo `json:"image"`

}

type Output struct {

	BuildRootID  uint64      `json:"buildroot_id"`

	Filename     string      `json:"filename"`

	FileSize     uint64      `json:"filesize"`

	Arch         string      `json:"arch"`

	ChecksumType string      `json:"checksum_type"` // must be 'md5'

	MD5          string      `json:"checksum"`

	Type         string      `json:"type"`

	Components   []Component `json:"component"`

	Extra        OutputExtra `json:"extra"`

}

type Metadata struct {

	MetadataVersion int         `json:"metadata_version"` // must be '0'

	Build           Build       `json:"build"`

	BuildRoots      []BuildRoot `json:"buildroots"`

	Output          []Output    `json:"output"`

}

type CGImportResult struct {

	BuildID int `xmlrpc:"build_id"`

}

// RoundTrip implements the RoundTripper interface, using the default

// transport. When a session has been established, also pass along the

// session credentials. This may not be how the RoundTripper interface

// is meant to be used, but the underlying XML-RPC helpers don't allow

// us to adjust the URL per-call (these arguments should really be in

// the body).

func (k *Koji) RoundTrip(req *http.Request) (*http.Response, error) {

	if k.sessionKey == "" {

		return http.DefaultTransport.RoundTrip(req)

	}

	// Clone the request, so as not to alter the passed in value.

	rClone := new(http.Request)

	*rClone = *req

	rClone.Header = make(http.Header, len(req.Header))

	for idx, header := range req.Header {

		rClone.Header[idx] = append([]string(nil), header...)

	}

	values := rClone.URL.Query()

	values.Add("session-id", fmt.Sprintf("%v", k.sessionID))

	values.Add("session-key", k.sessionKey)

	values.Add("callnum", fmt.Sprintf("%v", k.callnum))

	rClone.URL.RawQuery = values.Encode()

	// Each call is given a unique callnum.

	k.callnum++

	return http.DefaultTransport.RoundTrip(rClone)

}

func New(server string) (*Koji, error) {

	k := &Koji{}

	client, err := xmlrpc.NewClient(server, k)

	if err != nil {

		return nil, err

	}

	k.xmlrpc = client

	k.server = server

	return k, nil

}

// GetAPIVersion gets the version of the API of the remote Koji instance

func (k *Koji) GetAPIVersion() (int, error) {

	var version int

	err := k.xmlrpc.Call("getAPIVersion", nil, &version)

	if err != nil {

		return 0, err

	}

	return version, nil

}

// Login sets up a new session with the given user/password

func (k *Koji) Login(user, password string) error {

	args := []interface{}{user, password}

	var reply struct {

		SessionID  int64  `xmlrpc:"session-id"`

		SessionKey string `xmlrpc:"session-key"`

	}

	err := k.xmlrpc.Call("login", args, &reply)

	if err != nil {

		return err

	}

	k.sessionID = reply.SessionID

	k.sessionKey = reply.SessionKey

	k.callnum = 0

	return nil

}

// Logout ends the session

func (k *Koji) Logout() error {

	err := k.xmlrpc.Call("logout", nil, nil)

	if err != nil {

		return err

	}

	return nil

}

// CGImport imports previously uploaded content, by specifying its metadata, and the temporary

// directory where it is located.

func (k *Koji) CGImport(build Build, buildRoots []BuildRoot, output []Output, directory string) (*CGImportResult, error) {

	m := &Metadata{

		Build:      build,

		BuildRoots: buildRoots,

		Output:     output,

	}

	metadata, err := json.Marshal(m)

	if err != nil {

		return nil, err

	}

	var result CGImportResult

	err = k.xmlrpc.Call("CGImport", []interface{}{string(metadata), directory}, &result)

	if err != nil {

		return nil, err

	}

	return &result, nil

}

// uploadChunk uploads a byte slice to a given filepath/filname at a given offset

func (k *Koji) uploadChunk(chunk []byte, filepath, filename string, offset uint64) error {

	// We have to open-code a bastardized version of XML-RPC: We send an octet-stream, as

	// if it was an RPC call, and get a regular XML-RPC reply back. In addition to the

	// standard URL parameters, we also have to pass any other parameters as part of the

	// URL, as the body can only contain the payload.

	u, err := url.Parse(k.server)

	if err != nil {

		return err

	}

	q := u.Query()

	q.Add("filepath", filepath)

	q.Add("filename", filename)

	q.Add("offset", fmt.Sprintf("%v", offset))

	q.Add("fileverify", "adler32")

	q.Add("session-id", fmt.Sprintf("%v", k.sessionID))

	q.Add("session-key", k.sessionKey)

	q.Add("callnum", fmt.Sprintf("%v", k.callnum))

	u.RawQuery = q.Encode()

	// Each call is given a unique callnum.

	k.callnum++

	resp, err := http.Post(u.String(), "application/octet-stream", bytes.NewBuffer(chunk))

	if err != nil {

		return err

	}

	defer resp.Body.Close()

	body, err := ioutil.ReadAll(resp.Body)

	if err != nil {

		return err

	}

	err = xmlrpc.Response.Err(body)

	if err != nil {

		return err

	}

	var reply struct {

		Size      int    `xmlrpc:"size"`

		HexDigest string `xmlrpc:"hexdigest"`

	}

	err = xmlrpc.Response.Unmarshal(body, &reply)

	if err != nil {

		return fmt.Errorf("cannot unmarshal the xmlrpc response: %v", err)

	}

	if reply.Size != len(chunk) {

		return fmt.Errorf("Sent a chunk of %d bytes, but server got %d bytes", len(chunk), reply.Size)

	}

	digest := fmt.Sprintf("%08x", adler32.Checksum(chunk))

	if reply.HexDigest != digest {

		return fmt.Errorf("Sent a chunk with Adler32 digest %s, but server computed digest %s", digest, reply.HexDigest)

	}

	return nil

}

// Upload uploads file to the temporary filepath on the kojiserver under the name filename

// The md5sum and size of the file is returned on success.

func (k *Koji) Upload(file io.Reader, filepath, filename string) (string, uint64, error) {

	chunk := make([]byte, 1024*1024) // upload a megabyte at a time

	offset := uint64(0)

	hash := md5.New()

	for {

		n, err := file.Read(chunk)

		if err != nil {

			if err == io.EOF {

				break

			}

			return "", 0, err

		}

		err = k.uploadChunk(chunk[:n], filepath, filename, offset)

		if err != nil {

			return "", 0, err

		}

		offset += uint64(n)

		m, err := hash.Write(chunk[:n])

		if err != nil {

			return "", 0, err

		}

		if m != n {

			return "", 0, fmt.Errorf("sent %d bytes, but hashed %d", n, m)

		}

	}

	return fmt.Sprintf("%x", hash.Sum(nil)), offset, nil

}