package gitlab

import (
	"crypto/tls"
	"fmt"
	"io/ioutil"
	"net/http"
	"strconv"
	"strings"

	"github.com/Bugagazavr/go-gitlab-client"
	"github.com/drone/drone/Godeps/_workspace/src/github.com/hashicorp/golang-lru"
	"github.com/drone/drone/pkg/config"
	"github.com/drone/drone/pkg/oauth2"
	"github.com/drone/drone/pkg/remote"
	common "github.com/drone/drone/pkg/types"
	"github.com/drone/drone/pkg/utils/httputil"
)

const (
	DefaultScope = "repo"
)

type Gitlab struct {
	URL         string
	Client      string
	Secret      string
	AllowedOrgs []string
	Open        bool
	PrivateMode bool
	SkipVerify  bool

	cache *lru.Cache
}

func init() {
	remote.Register("gitlab", NewDriver)
}

func NewDriver(conf *config.Config) (remote.Remote, error) {
	var gitlab = Gitlab{
		URL:         conf.Gitlab.URL,
		Client:      conf.Gitlab.Client,
		Secret:      conf.Gitlab.Secret,
		AllowedOrgs: conf.Gitlab.Orgs,
		Open:        conf.Gitlab.Open,
		SkipVerify:  conf.Gitlab.SkipVerify,
	}
	var err error
	gitlab.cache, err = lru.New(1028)
	if err != nil {
		return nil, err
	}

	// the URL must NOT have a trailing slash
	if strings.HasSuffix(gitlab.URL, "/") {
		gitlab.URL = gitlab.URL[:len(gitlab.URL)-1]
	}
	return &gitlab, nil
}

func (r *Gitlab) Login(token, secret string) (*common.User, error) {
	client := NewClient(r.URL, token, r.SkipVerify)
	var login, err = client.CurrentUser()
	if err != nil {
		return nil, err
	}
	user := common.User{}
	user.Login = login.Username
	user.Email = login.Email
	user.Token = token
	user.Secret = secret
	return &user, nil
}

// Orgs fetches the organizations for the given user.
func (r *Gitlab) Orgs(u *common.User) ([]string, error) {
	return nil, nil
}

// Repo fetches the named repository from the remote system.
func (r *Gitlab) Repo(u *common.User, owner, name string) (*common.Repo, error) {
	client := NewClient(r.URL, u.Token, r.SkipVerify)
	id := ns(owner, name)
	repo_, err := client.Project(id)
	if err != nil {
		return nil, err
	}

	repo := &common.Repo{}
	repo.Owner = owner
	repo.Name = name
	repo.FullName = repo_.PathWithNamespace
	repo.Link = repo_.Url
	repo.Clone = repo_.HttpRepoUrl
	repo.Branch = "master"

	if repo_.DefaultBranch != "" {
		repo.Branch = repo_.DefaultBranch
	}

	if r.PrivateMode {
		repo.Private = true
	}
	return repo, err
}

// Perm fetches the named repository from the remote system.
func (r *Gitlab) Perm(u *common.User, owner, name string) (*common.Perm, error) {
	key := fmt.Sprintf("%s/%s/%s", u.Login, owner, name)
	val, ok := r.cache.Get(key)
	if ok {
		return val.(*common.Perm), nil
	}

	client := NewClient(r.URL, u.Token, r.SkipVerify)
	id := ns(owner, name)
	repo, err := client.Project(id)
	if err != nil {
		return nil, err
	}
	m := &common.Perm{}
	m.Admin = IsAdmin(repo)
	m.Pull = IsRead(repo)
	m.Push = IsWrite(repo)
	r.cache.Add(key, m)
	return m, nil
}

// GetScript fetches the build script (.drone.yml) from the remote
// repository and returns in string format.
func (r *Gitlab) Script(user *common.User, repo *common.Repo, build *common.Build) ([]byte, error) {
	var client = NewClient(r.URL, user.Token, r.SkipVerify)
	var path = ns(repo.Owner, repo.Name)
	return client.RepoRawFile(path, build.Commit.Sha, ".drone.yml")
}

// NOTE Currently gitlab doesn't support status for commits and events,
//      also if we want get MR status in gitlab we need implement a special plugin for gitlab,
//      gitlab uses API to fetch build status on client side. But for now we skip this.
func (r *Gitlab) Status(u *common.User, repo *common.Repo, b *common.Build) error {
	return nil
}

// Netrc returns a .netrc file that can be used to clone
// private repositories from a remote system.
// NOTE gitlab does not support this, so now we skip this.
func (r *Gitlab) Netrc(u *common.User) (*common.Netrc, error) {
	return nil, nil
}

// Activate activates a repository by adding a Post-commit hook and
// a Public Deploy key, if applicable.
func (r *Gitlab) Activate(user *common.User, repo *common.Repo, keys *common.Keypair, link string) error {
	var client = NewClient(r.URL, user.Token, r.SkipVerify)
	var path = ns(repo.Owner, repo.Name)
	var title, err = GetKeyTitle(link)
	if err != nil {
		return err
	}

	// if the repository is private we'll need
	// to upload a github key to the repository
	if repo.Private {
		var err = client.AddProjectDeployKey(path, title, repo.Keys.Public)
		if err != nil {
			return err
		}
	}

	// append the repo owner / name to the hook url since gitlab
	// doesn't send this detail in the post-commit hook
	link += "?owner=" + repo.Owner + "&name=" + repo.Name

	// add the hook
	return client.AddProjectHook(path, link, true, false, true)
}

// Deactivate removes a repository by removing all the post-commit hooks
// which are equal to link and removing the SSH deploy key.
func (r *Gitlab) Deactivate(user *common.User, repo *common.Repo, link string) error {
	var client = NewClient(r.URL, user.Token, r.SkipVerify)
	var path = ns(repo.Owner, repo.Name)

	keys, err := client.ProjectDeployKeys(path)
	if err != nil {
		return err
	}
	var pubkey = strings.TrimSpace(repo.Keys.Public)
	for _, k := range keys {
		if pubkey == strings.TrimSpace(k.Key) {
			if err := client.RemoveProjectDeployKey(path, strconv.Itoa(k.Id)); err != nil {
				return err
			}
			break
		}
	}
	hooks, err := client.ProjectHooks(path)
	if err != nil {
		return err
	}
	link += "?owner=" + repo.Owner + "&name=" + repo.Name
	for _, h := range hooks {
		if link == h.Url {
			if err := client.RemoveProjectHook(path, strconv.Itoa(h.Id)); err != nil {
				return err
			}
			break
		}
	}
	return nil
}

// ParseHook parses the post-commit hook from the Request body
// and returns the required data in a standard format.
// NOTE: in gitlab 8.0, gitlab will get same MR models as github
//       https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/981/diffs
func (r *Gitlab) Hook(req *http.Request) (*common.Hook, error) {

	var payload, _ = ioutil.ReadAll(req.Body)
	var parsed, _ = gogitlab.ParseHook(payload)
	obj := parsed.ObjectAttributes

	if !(obj.State == "opened" && obj.MergeStatus == "unchecked") {
		return nil, nil
	}

	var hook = new(common.Hook)

	hook.Repo.Name = obj.Source.Name
	hook.Repo.Owner = obj.Source.Namespace

	// Check pull request comes from public fork
	if obj.Source.VisibilityLevel < 20 {
		//hook.SourceRemote = obj.Source.SshUrl
		// If pull request source repo is not a public
		// check for non-internal pull request
		if obj.Source.Name != obj.Target.Name || obj.Source.Namespace != obj.Target.Namespace {
			return nil, nil
		}
	} else {
		//hook.SourceRemote = obj.Source.HttpUrl
	}

	hook.Commit.Author.Login = req.FormValue("owner")
	//hook.Repo = req.FormValue("name")
	hook.Commit.Sha = obj.LastCommit.Id
	hook.Commit.Branch = obj.TargetBranch
	//hook.Commit.SourceBranch = obj.SourceBranch
	hook.Commit.Timestamp = obj.LastCommit.Timestamp
	hook.Commit.Message = obj.Title

	if obj.LastCommit.Author == nil {
		// Waiting for merge https://github.com/gitlabhq/gitlabhq/pull/7967
		hook.Commit.Author.Email = ""
	} else {
		hook.Commit.Author.Email = obj.LastCommit.Author.Email
	}

	hook.PullRequest.Number = obj.IId

	return hook, nil
}

// ¯\_(ツ)_/¯
func (g *Gitlab) Oauth2Transport(r *http.Request) *oauth2.Transport {
	return &oauth2.Transport{
		Config: &oauth2.Config{
			ClientId:     g.Client,
			ClientSecret: g.Secret,
			Scope:        DefaultScope,
			AuthURL:      fmt.Sprintf("%s/oauth/authorize", g.URL),
			TokenURL:     fmt.Sprintf("%s/oauth/access_token", g.URL),
			RedirectURL:  fmt.Sprintf("%s/authorize", httputil.GetURL(r)),
			//settings.Server.Scheme, settings.Server.Hostname),
		},
		Transport: &http.Transport{
			Proxy:           http.ProxyFromEnvironment,
			TLSClientConfig: &tls.Config{InsecureSkipVerify: g.SkipVerify},
		},
	}
}

// Accessor method, to allowed remote organizations field.
func (r *Gitlab) GetOrgs() []string {
	return r.AllowedOrgs
}

// Accessor method, to open field.
func (r *Gitlab) GetOpen() bool {
	return r.Open
}

// return default scope for GitHub
func (r *Gitlab) Scope() string {
	return DefaultScope
}