forgejo/models/issue.go

// Copyright 2014 The Gogs Authors. All rights reserved.
// Use of this source code is governed by a MIT-style
// license that can be found in the LICENSE file.

package models

import (
	"bytes"
	"errors"
	"html/template"
	"os"
	"strconv"
	"strings"
	"time"

	"github.com/Unknwon/com"
	"github.com/go-xorm/xorm"

	"github.com/gogits/gogs/modules/log"
	"github.com/gogits/gogs/modules/setting"
)

var (
	ErrIssueNotExist       = errors.New("Issue does not exist")
	ErrLabelNotExist       = errors.New("Label does not exist")
	ErrWrongIssueCounter   = errors.New("Invalid number of issues for this milestone")
	ErrAttachmentNotExist  = errors.New("Attachment does not exist")
	ErrAttachmentNotLinked = errors.New("Attachment does not belong to this issue")
	ErrMissingIssueNumber  = errors.New("No issue number specified")
)

// Issue represents an issue or pull request of repository.
type Issue struct {
	ID              int64 `xorm:"pk autoincr"`
	RepoID          int64 `xorm:"INDEX"`
	Index           int64 // Index in one repository.
	Name            string
	Repo            *Repository `xorm:"-"`
	PosterID        int64
	Poster          *User    `xorm:"-"`
	LabelIds        string   `xorm:"TEXT"`
	Labels          []*Label `xorm:"-"`
	MilestoneID     int64
	Milestone       *Milestone `xorm:"-"`
	AssigneeID      int64
	Assignee        *User `xorm:"-"`
	IsRead          bool  `xorm:"-"`
	IsPull          bool  // Indicates whether is a pull request or not.
	IsClosed        bool
	Content         string `xorm:"TEXT"`
	RenderedContent string `xorm:"-"`
	Priority        int
	NumComments     int
	Deadline        time.Time
	Created         time.Time `xorm:"CREATED"`
	Updated         time.Time `xorm:"UPDATED"`
}

func (i *Issue) AfterSet(colName string, _ xorm.Cell) {
	var err error
	switch colName {
	case "milestone_id":
		i.Milestone, err = GetMilestoneByID(i.MilestoneID)
		if err != nil {
			log.Error(3, "GetMilestoneById: %v", err)
		}
	}
}

func (i *Issue) GetPoster() (err error) {
	i.Poster, err = GetUserById(i.PosterID)
	if IsErrUserNotExist(err) {
		i.Poster = &User{Name: "FakeUser"}
		return nil
	}
	return err
}

func (i *Issue) GetLabels() error {
	if len(i.LabelIds) < 3 {
		return nil
	}

	strIds := strings.Split(strings.TrimSuffix(i.LabelIds[1:], "|"), "|$")
	i.Labels = make([]*Label, 0, len(strIds))
	for _, strId := range strIds {
		id := com.StrTo(strId).MustInt64()
		if id > 0 {
			l, err := GetLabelById(id)
			if err != nil {
				if err == ErrLabelNotExist {
					continue
				}
				return err
			}
			i.Labels = append(i.Labels, l)
		}
	}
	return nil
}

func (i *Issue) GetAssignee() (err error) {
	if i.AssigneeID == 0 {
		return nil
	}

	i.Assignee, err = GetUserById(i.AssigneeID)
	if IsErrUserNotExist(err) {
		return nil
	}
	return err
}

func (i *Issue) Attachments() []*Attachment {
	a, _ := GetAttachmentsForIssue(i.ID)
	return a
}

func (i *Issue) AfterDelete() {
	_, err := DeleteAttachmentsByIssue(i.ID, true)

	if err != nil {
		log.Info("Could not delete files for issue #%d: %s", i.ID, err)
	}
}

// CreateIssue creates new issue for repository.
func NewIssue(issue *Issue) (err error) {
	sess := x.NewSession()
	defer sessionRelease(sess)
	if err = sess.Begin(); err != nil {
		return err
	}

	if _, err = sess.Insert(issue); err != nil {
		return err
	} else if _, err = sess.Exec("UPDATE `repository` SET num_issues = num_issues + 1 WHERE id = ?", issue.RepoID); err != nil {
		return err
	}

	if err = sess.Commit(); err != nil {
		return err
	}

	if issue.MilestoneID > 0 {
		// FIXES(280): Update milestone counter.
		return ChangeMilestoneAssign(0, issue.MilestoneID, issue)
	}

	return
}

// GetIssueByRef returns an Issue specified by a GFM reference.
// See https://help.github.com/articles/writing-on-github#references for more information on the syntax.
func GetIssueByRef(ref string) (issue *Issue, err error) {
	var issueNumber int64
	var repo *Repository

	n := strings.IndexByte(ref, byte('#'))

	if n == -1 {
		return nil, ErrMissingIssueNumber
	}

	if issueNumber, err = strconv.ParseInt(ref[n+1:], 10, 64); err != nil {
		return
	}

	if repo, err = GetRepositoryByRef(ref[:n]); err != nil {
		return
	}

	return GetIssueByIndex(repo.Id, issueNumber)
}

// GetIssueByIndex returns issue by given index in repository.
func GetIssueByIndex(rid, index int64) (*Issue, error) {
	issue := &Issue{RepoID: rid, Index: index}
	has, err := x.Get(issue)
	if err != nil {
		return nil, err
	} else if !has {
		return nil, ErrIssueNotExist
	}
	return issue, nil
}

// GetIssueById returns an issue by ID.
func GetIssueById(id int64) (*Issue, error) {
	issue := &Issue{ID: id}
	has, err := x.Get(issue)
	if err != nil {
		return nil, err
	} else if !has {
		return nil, ErrIssueNotExist
	}
	return issue, nil
}

// Issues returns a list of issues by given conditions.
func Issues(uid, assigneeID, repoID, posterID, milestoneID int64, page int, isClosed, isMention bool, labelIds, sortType string) ([]*Issue, error) {
	sess := x.Limit(setting.IssuePagingNum, (page-1)*setting.IssuePagingNum)

	if repoID > 0 {
		sess.Where("issue.repo_id=?", repoID).And("issue.is_closed=?", isClosed)
	} else {
		sess.Where("issue.is_closed=?", isClosed)
	}

	if assigneeID > 0 {
		sess.And("issue.assignee_id=?", assigneeID)
	} else if posterID > 0 {
		sess.And("issue.poster_id=?", posterID)
	}

	if milestoneID > 0 {
		sess.And("issue.milestone_id=?", milestoneID)
	}

	if len(labelIds) > 0 {
		for _, label := range strings.Split(labelIds, ",") {
			if com.StrTo(label).MustInt() > 0 {
				sess.And("label_ids like ?", "%$"+label+"|%")
			}
		}
	}

	switch sortType {
	case "oldest":
		sess.Asc("created")
	case "recentupdate":
		sess.Desc("updated")
	case "leastupdate":
		sess.Asc("updated")
	case "mostcomment":
		sess.Desc("num_comments")
	case "leastcomment":
		sess.Asc("num_comments")
	case "priority":
		sess.Desc("priority")
	default:
		sess.Desc("created")
	}

	if isMention {
		queryStr := "issue.id = issue_user.issue_id AND issue_user.is_mentioned=1"
		if uid > 0 {
			queryStr += " AND issue_user.uid = " + com.ToStr(uid)
		}
		sess.Join("INNER", "issue_user", queryStr)
	}

	issues := make([]*Issue, 0, setting.IssuePagingNum)
	return issues, sess.Find(&issues)
}

type IssueStatus int

const (
	IS_OPEN = iota + 1
	IS_CLOSE
)

// GetIssuesByLabel returns a list of issues by given label and repository.
func GetIssuesByLabel(repoID, labelID int64) ([]*Issue, error) {
	issues := make([]*Issue, 0, 10)
	return issues, x.Where("repo_id=?", repoID).And("label_ids like '%$" + com.ToStr(labelID) + "|%'").Find(&issues)
}

// GetIssueCountByPoster returns number of issues of repository by poster.
func GetIssueCountByPoster(uid, rid int64, isClosed bool) int64 {
	count, _ := x.Where("repo_id=?", rid).And("poster_id=?", uid).And("is_closed=?", isClosed).Count(new(Issue))
	return count
}

// .___                             ____ ___
// |   | ______ ________ __   ____ |    |   \______ ___________
// |   |/  ___//  ___/  |  \_/ __ \|    |   /  ___// __ \_  __ \
// |   |\___ \ \___ \|  |  /\  ___/|    |  /\___ \\  ___/|  | \/
// |___/____  >____  >____/  \___  >______//____  >\___  >__|
//          \/     \/            \/             \/     \/

// IssueUser represents an issue-user relation.
type IssueUser struct {
	Id          int64
	Uid         int64 `xorm:"INDEX"` // User ID.
	IssueId     int64
	RepoId      int64 `xorm:"INDEX"`
	MilestoneId int64
	IsRead      bool
	IsAssigned  bool
	IsMentioned bool
	IsPoster    bool
	IsClosed    bool
}

// FIXME: organization
// NewIssueUserPairs adds new issue-user pairs for new issue of repository.
func NewIssueUserPairs(repo *Repository, issueID, orgID, posterID, assigneeID int64) error {
	users, err := repo.GetCollaborators()
	if err != nil {
		return err
	}

	iu := &IssueUser{
		IssueId: issueID,
		RepoId:  repo.Id,
	}

	isNeedAddPoster := true
	for _, u := range users {
		iu.Id = 0
		iu.Uid = u.Id
		iu.IsPoster = iu.Uid == posterID
		if isNeedAddPoster && iu.IsPoster {
			isNeedAddPoster = false
		}
		iu.IsAssigned = iu.Uid == assigneeID
		if _, err = x.Insert(iu); err != nil {
			return err
		}
	}
	if isNeedAddPoster {
		iu.Id = 0
		iu.Uid = posterID
		iu.IsPoster = true
		iu.IsAssigned = iu.Uid == assigneeID
		if _, err = x.Insert(iu); err != nil {
			return err
		}
	}

	// Add owner's as well.
	if repo.OwnerId != posterID {
		iu.Id = 0
		iu.Uid = repo.OwnerId
		iu.IsAssigned = iu.Uid == assigneeID
		if _, err = x.Insert(iu); err != nil {
			return err
		}
	}

	return nil
}

// PairsContains returns true when pairs list contains given issue.
func PairsContains(ius []*IssueUser, issueId, uid int64) int {
	for i := range ius {
		if ius[i].IssueId == issueId &&
			ius[i].Uid == uid {
			return i
		}
	}
	return -1
}

// GetIssueUserPairs returns issue-user pairs by given repository and user.
func GetIssueUserPairs(rid, uid int64, isClosed bool) ([]*IssueUser, error) {
	ius := make([]*IssueUser, 0, 10)
	err := x.Where("is_closed=?", isClosed).Find(&ius, &IssueUser{RepoId: rid, Uid: uid})
	return ius, err
}

// GetIssueUserPairsByRepoIds returns issue-user pairs by given repository IDs.
func GetIssueUserPairsByRepoIds(rids []int64, isClosed bool, page int) ([]*IssueUser, error) {
	if len(rids) == 0 {
		return []*IssueUser{}, nil
	}

	buf := bytes.NewBufferString("")
	for _, rid := range rids {
		buf.WriteString("repo_id=")
		buf.WriteString(com.ToStr(rid))
		buf.WriteString(" OR ")
	}
	cond := strings.TrimSuffix(buf.String(), " OR ")
	ius := make([]*IssueUser, 0, 10)
	sess := x.Limit(20, (page-1)*20).Where("is_closed=?", isClosed)
	if len(cond) > 0 {
		sess.And(cond)
	}
	err := sess.Find(&ius)
	return ius, err
}

// GetIssueUserPairsByMode returns issue-user pairs by given repository and user.
func GetIssueUserPairsByMode(uid, rid int64, isClosed bool, page, filterMode int) ([]*IssueUser, error) {
	ius := make([]*IssueUser, 0, 10)
	sess := x.Limit(20, (page-1)*20).Where("uid=?", uid).And("is_closed=?", isClosed)
	if rid > 0 {
		sess.And("repo_id=?", rid)
	}

	switch filterMode {
	case FM_ASSIGN:
		sess.And("is_assigned=?", true)
	case FM_CREATE:
		sess.And("is_poster=?", true)
	default:
		return ius, nil
	}
	err := sess.Find(&ius)
	return ius, err
}

// IssueStats represents issue statistic information.
type IssueStats struct {
	OpenCount, ClosedCount int64
	AllCount               int64
	AssignCount            int64
	CreateCount            int64
	MentionCount           int64
}

// Filter modes.
const (
	FM_ALL = iota
	FM_ASSIGN
	FM_CREATE
	FM_MENTION
)

// GetIssueStats returns issue statistic information by given conditions.
func GetIssueStats(repoID, uid, labelID, milestoneID int64, isShowClosed bool, filterMode int) *IssueStats {
	stats := &IssueStats{}
	issue := new(Issue)

	queryStr := "issue.repo_id=? AND issue.is_closed=?"
	if labelID > 0 {
		queryStr += " AND issue.label_ids like '%$" + com.ToStr(labelID) + "|%'"
	}
	if milestoneID > 0 {
		queryStr += " AND milestone_id=" + com.ToStr(milestoneID)
	}
	switch filterMode {
	case FM_ALL:
		stats.OpenCount, _ = x.Where(queryStr, repoID, false).Count(issue)
		stats.ClosedCount, _ = x.Where(queryStr, repoID, true).Count(issue)
		return stats

	case FM_ASSIGN:
		queryStr += " AND assignee_id=?"
		stats.OpenCount, _ = x.Where(queryStr, repoID, false, uid).Count(issue)
		stats.ClosedCount, _ = x.Where(queryStr, repoID, true, uid).Count(issue)
		return stats

	case FM_CREATE:
		queryStr += " AND poster_id=?"
		stats.OpenCount, _ = x.Where(queryStr, repoID, false, uid).Count(issue)
		stats.ClosedCount, _ = x.Where(queryStr, repoID, true, uid).Count(issue)
		return stats

	case FM_MENTION:
		queryStr += " AND uid=? AND is_mentioned=?"
		if labelID > 0 {
			stats.OpenCount, _ = x.Where(queryStr, repoID, false, uid, true).
				Join("INNER", "issue", "issue.id = issue_id").Count(new(IssueUser))
			stats.ClosedCount, _ = x.Where(queryStr, repoID, true, uid, true).
				Join("INNER", "issue", "issue.id = issue_id").Count(new(IssueUser))
			return stats
		}

		queryStr = strings.Replace(queryStr, "issue.", "", 2)
		stats.OpenCount, _ = x.Where(queryStr, repoID, false, uid, true).Count(new(IssueUser))
		stats.ClosedCount, _ = x.Where(queryStr, repoID, true, uid, true).Count(new(IssueUser))
		return stats
	}
	return stats
}

// GetUserIssueStats returns issue statistic information for dashboard by given conditions.
func GetUserIssueStats(uid int64, filterMode int) *IssueStats {
	stats := &IssueStats{}
	issue := new(Issue)
	stats.AssignCount, _ = x.Where("assignee_id=?", uid).And("is_closed=?", false).Count(issue)
	stats.CreateCount, _ = x.Where("poster_id=?", uid).And("is_closed=?", false).Count(issue)
	return stats
}

// UpdateIssue updates information of issue.
func UpdateIssue(issue *Issue) error {
	_, err := x.Id(issue.ID).AllCols().Update(issue)

	if err != nil {
		return err
	}

	return err
}

// UpdateIssueUserByStatus updates issue-user pairs by issue status.
func UpdateIssueUserPairsByStatus(iid int64, isClosed bool) error {
	rawSql := "UPDATE `issue_user` SET is_closed = ? WHERE issue_id = ?"
	_, err := x.Exec(rawSql, isClosed, iid)
	return err
}

// UpdateIssueUserPairByAssignee updates issue-user pair for assigning.
func UpdateIssueUserPairByAssignee(aid, iid int64) error {
	rawSql := "UPDATE `issue_user` SET is_assigned = ? WHERE issue_id = ?"
	if _, err := x.Exec(rawSql, false, iid); err != nil {
		return err
	}

	// Assignee ID equals to 0 means clear assignee.
	if aid == 0 {
		return nil
	}
	rawSql = "UPDATE `issue_user` SET is_assigned = ? WHERE uid = ? AND issue_id = ?"
	_, err := x.Exec(rawSql, true, aid, iid)
	return err
}

// UpdateIssueUserPairByRead updates issue-user pair for reading.
func UpdateIssueUserPairByRead(uid, iid int64) error {
	rawSql := "UPDATE `issue_user` SET is_read = ? WHERE uid = ? AND issue_id = ?"
	_, err := x.Exec(rawSql, true, uid, iid)
	return err
}

// UpdateIssueUserPairsByMentions updates issue-user pairs by mentioning.
func UpdateIssueUserPairsByMentions(uids []int64, iid int64) error {
	for _, uid := range uids {
		iu := &IssueUser{Uid: uid, IssueId: iid}
		has, err := x.Get(iu)
		if err != nil {
			return err
		}

		iu.IsMentioned = true
		if has {
			_, err = x.Id(iu.Id).AllCols().Update(iu)
		} else {
			_, err = x.Insert(iu)
		}
		if err != nil {
			return err
		}
	}
	return nil
}

// .____          ___.          .__
// |    |   _____ \_ |__   ____ |  |
// |    |   \__  \ | __ \_/ __ \|  |
// |    |___ / __ \| \_\ \  ___/|  |__
// |_______ (____  /___  /\___  >____/
//         \/    \/    \/     \/

// Label represents a label of repository for issues.
type Label struct {
	ID              int64 `xorm:"pk autoincr"`
	RepoId          int64 `xorm:"INDEX"`
	Name            string
	Color           string `xorm:"VARCHAR(7)"`
	NumIssues       int
	NumClosedIssues int
	NumOpenIssues   int  `xorm:"-"`
	IsChecked       bool `xorm:"-"`
}

// CalOpenIssues calculates the open issues of label.
func (m *Label) CalOpenIssues() {
	m.NumOpenIssues = m.NumIssues - m.NumClosedIssues
}

// NewLabel creates new label of repository.
func NewLabel(l *Label) error {
	_, err := x.Insert(l)
	return err
}

// GetLabelById returns a label by given ID.
func GetLabelById(id int64) (*Label, error) {
	if id <= 0 {
		return nil, ErrLabelNotExist
	}

	l := &Label{ID: id}
	has, err := x.Get(l)
	if err != nil {
		return nil, err
	} else if !has {
		return nil, ErrLabelNotExist
	}
	return l, nil
}

// GetLabels returns a list of labels of given repository ID.
func GetLabels(repoId int64) ([]*Label, error) {
	labels := make([]*Label, 0, 10)
	err := x.Where("repo_id=?", repoId).Find(&labels)
	return labels, err
}

// UpdateLabel updates label information.
func UpdateLabel(l *Label) error {
	_, err := x.Id(l.ID).AllCols().Update(l)
	return err
}

// DeleteLabel delete a label of given repository.
func DeleteLabel(repoID, labelID int64) error {
	l, err := GetLabelById(labelID)
	if err != nil {
		if err == ErrLabelNotExist {
			return nil
		}
		return err
	}

	issues, err := GetIssuesByLabel(repoID, labelID)
	if err != nil {
		return err
	}

	sess := x.NewSession()
	defer sessionRelease(sess)
	if err = sess.Begin(); err != nil {
		return err
	}

	for _, issue := range issues {
		issue.LabelIds = strings.Replace(issue.LabelIds, "$"+com.ToStr(labelID)+"|", "", -1)
		if _, err = sess.Id(issue.ID).AllCols().Update(issue); err != nil {
			return err
		}
	}

	if _, err = sess.Delete(l); err != nil {
		return err
	}
	return sess.Commit()
}

//    _____  .__.__                   __
//   /     \ |__|  |   ____   _______/  |_  ____   ____   ____
//  /  \ /  \|  |  | _/ __ \ /  ___/\   __\/  _ \ /    \_/ __ \
// /    Y    \  |  |_\  ___/ \___ \  |  | (  <_> )   |  \  ___/
// \____|__  /__|____/\___  >____  > |__|  \____/|___|  /\___  >
//         \/             \/     \/                   \/     \/

// Milestone represents a milestone of repository.
type Milestone struct {
	ID              int64 `xorm:"pk autoincr"`
	RepoID          int64 `xorm:"INDEX"`
	Name            string
	Content         string `xorm:"TEXT"`
	RenderedContent string `xorm:"-"`
	IsClosed        bool
	NumIssues       int
	NumClosedIssues int
	NumOpenIssues   int `xorm:"-"`
	Completeness    int // Percentage(1-100).
	Deadline        time.Time
	DeadlineString  string `xorm:"-"`
	IsOverDue       bool   `xorm:"-"`
	ClosedDate      time.Time
}

func (m *Milestone) AfterSet(colName string, _ xorm.Cell) {
	if colName == "deadline" {
		if m.Deadline.Year() == 9999 {
			return
		}

		m.DeadlineString = m.Deadline.Format("2006-01-02")
		if time.Now().After(m.Deadline) {
			m.IsOverDue = true
		}
	}
}

// CalOpenIssues calculates the open issues of milestone.
func (m *Milestone) CalOpenIssues() {
	m.NumOpenIssues = m.NumIssues - m.NumClosedIssues
}

// NewMilestone creates new milestone of repository.
func NewMilestone(m *Milestone) (err error) {
	sess := x.NewSession()
	defer sessionRelease(sess)
	if err = sess.Begin(); err != nil {
		return err
	}

	if _, err = sess.Insert(m); err != nil {
		return err
	}

	if _, err = sess.Exec("UPDATE `repository` SET num_milestones=num_milestones+1 WHERE id=?", m.RepoID); err != nil {
		return err
	}
	return sess.Commit()
}

// GetMilestoneByID returns the milestone of given ID.
func GetMilestoneByID(id int64) (*Milestone, error) {
	m := &Milestone{ID: id}
	has, err := x.Get(m)
	if err != nil {
		return nil, err
	} else if !has {
		return nil, ErrMilestoneNotExist{id}
	}
	return m, nil
}

// GetAllRepoMilestones returns all milestones of given repository.
func GetAllRepoMilestones(repoID int64) ([]*Milestone, error) {
	miles := make([]*Milestone, 0, 10)
	return miles, x.Where("repo_id=?", repoID).Find(&miles)
}

// GetMilestones returns a list of milestones of given repository and status.
func GetMilestones(repoID int64, page int, isClosed bool) ([]*Milestone, error) {
	miles := make([]*Milestone, 0, setting.IssuePagingNum)
	sess := x.Where("repo_id=? AND is_closed=?", repoID, isClosed)
	if page > 0 {
		sess = sess.Limit(setting.IssuePagingNum, (page-1)*setting.IssuePagingNum)
	}
	return miles, sess.Find(&miles)
}

func updateMilestone(e Engine, m *Milestone) error {
	_, err := e.Id(m.ID).AllCols().Update(m)
	return err
}

// UpdateMilestone updates information of given milestone.
func UpdateMilestone(m *Milestone) error {
	return updateMilestone(x, m)
}

func countRepoMilestones(e Engine, repoID int64) int64 {
	count, _ := e.Where("repo_id=?", repoID).Count(new(Milestone))
	return count
}

// CountRepoMilestones returns number of milestones in given repository.
func CountRepoMilestones(repoID int64) int64 {
	return countRepoMilestones(x, repoID)
}

func countRepoClosedMilestones(e Engine, repoID int64) int64 {
	closed, _ := e.Where("repo_id=? AND is_closed=?", repoID, true).Count(new(Milestone))
	return closed
}

// CountRepoClosedMilestones returns number of closed milestones in given repository.
func CountRepoClosedMilestones(repoID int64) int64 {
	return countRepoClosedMilestones(x, repoID)
}

// MilestoneStats returns number of open and closed milestones of given repository.
func MilestoneStats(repoID int64) (open int64, closed int64) {
	open, _ = x.Where("repo_id=? AND is_closed=?", repoID, false).Count(new(Milestone))
	return open, CountRepoClosedMilestones(repoID)
}

// ChangeMilestoneStatus changes the milestone open/closed status.
func ChangeMilestoneStatus(m *Milestone, isClosed bool) (err error) {
	repo, err := GetRepositoryById(m.RepoID)
	if err != nil {
		return err
	}

	sess := x.NewSession()
	defer sessionRelease(sess)
	if err = sess.Begin(); err != nil {
		return err
	}

	m.IsClosed = isClosed
	if err = updateMilestone(sess, m); err != nil {
		return err
	}

	repo.NumMilestones = int(countRepoMilestones(sess, repo.Id))
	repo.NumClosedMilestones = int(countRepoClosedMilestones(sess, repo.Id))
	if _, err = sess.Id(repo.Id).AllCols().Update(repo); err != nil {
		return err
	}
	return sess.Commit()
}

// ChangeMilestoneIssueStats updates the open/closed issues counter and progress
// for the milestone associated witht the given issue.
func ChangeMilestoneIssueStats(issue *Issue) error {
	if issue.MilestoneID == 0 {
		return nil
	}

	m, err := GetMilestoneByID(issue.MilestoneID)
	if err != nil {
		return err
	}

	if issue.IsClosed {
		m.NumOpenIssues--
		m.NumClosedIssues++
	} else {
		m.NumOpenIssues++
		m.NumClosedIssues--
	}

	m.Completeness = m.NumClosedIssues * 100 / m.NumIssues

	return UpdateMilestone(m)
}

// ChangeMilestoneAssign changes assignment of milestone for issue.
func ChangeMilestoneAssign(oldMid, mid int64, issue *Issue) (err error) {
	sess := x.NewSession()
	defer sess.Close()
	if err = sess.Begin(); err != nil {
		return err
	}

	if oldMid > 0 {
		m, err := GetMilestoneByID(oldMid)
		if err != nil {
			return err
		}

		m.NumIssues--
		if issue.IsClosed {
			m.NumClosedIssues--
		}
		if m.NumIssues > 0 {
			m.Completeness = m.NumClosedIssues * 100 / m.NumIssues
		} else {
			m.Completeness = 0
		}

		if _, err = sess.Id(m.ID).Cols("num_issues,num_completeness,num_closed_issues").Update(m); err != nil {
			sess.Rollback()
			return err
		}

		rawSql := "UPDATE `issue_user` SET milestone_id = 0 WHERE issue_id = ?"
		if _, err = sess.Exec(rawSql, issue.ID); err != nil {
			sess.Rollback()
			return err
		}
	}

	if mid > 0 {
		m, err := GetMilestoneByID(mid)
		if err != nil {
			return err
		}

		m.NumIssues++
		if issue.IsClosed {
			m.NumClosedIssues++
		}

		if m.NumIssues == 0 {
			return ErrWrongIssueCounter
		}

		m.Completeness = m.NumClosedIssues * 100 / m.NumIssues
		if _, err = sess.Id(m.ID).Cols("num_issues,num_completeness,num_closed_issues").Update(m); err != nil {
			sess.Rollback()
			return err
		}

		rawSql := "UPDATE `issue_user` SET milestone_id = ? WHERE issue_id = ?"
		if _, err = sess.Exec(rawSql, m.ID, issue.ID); err != nil {
			sess.Rollback()
			return err
		}
	}

	return sess.Commit()
}

// DeleteMilestoneByID deletes a milestone by given ID.
func DeleteMilestoneByID(mid int64) error {
	m, err := GetMilestoneByID(mid)
	if err != nil {
		if IsErrMilestoneNotExist(err) {
			return nil
		}
		return err
	}

	repo, err := GetRepositoryById(m.RepoID)
	if err != nil {
		return err
	}

	sess := x.NewSession()
	defer sessionRelease(sess)
	if err = sess.Begin(); err != nil {
		return err
	}

	if _, err = sess.Id(m.ID).Delete(m); err != nil {
		return err
	}

	repo.NumMilestones = int(countRepoMilestones(sess, repo.Id))
	repo.NumClosedMilestones = int(countRepoClosedMilestones(sess, repo.Id))
	if _, err = sess.Id(repo.Id).AllCols().Update(repo); err != nil {
		return err
	}

	if _, err = sess.Exec("UPDATE `issue` SET milestone_id=0 WHERE milestone_id=?", m.ID); err != nil {
		return err
	} else if _, err = sess.Exec("UPDATE `issue_user` SET milestone_id=0 WHERE milestone_id=?", m.ID); err != nil {
		return err
	}
	return sess.Commit()
}

// _________                                       __
// \_   ___ \  ____   _____   _____   ____   _____/  |_
// /    \  \/ /  _ \ /     \ /     \_/ __ \ /    \   __\
// \     \___(  <_> )  Y Y  \  Y Y  \  ___/|   |  \  |
//  \______  /\____/|__|_|  /__|_|  /\___  >___|  /__|
//         \/             \/      \/     \/     \/

// CommentType defines whether a comment is just a simple comment, an action (like close) or a reference.
type CommentType int

const (
	// Plain comment, can be associated with a commit (CommitId > 0) and a line (Line > 0)
	COMMENT_TYPE_COMMENT CommentType = iota
	COMMENT_TYPE_REOPEN
	COMMENT_TYPE_CLOSE

	// References.
	COMMENT_TYPE_ISSUE
	// Reference from some commit (not part of a pull request)
	COMMENT_TYPE_COMMIT
	// Reference from some pull request
	COMMENT_TYPE_PULL
)

// Comment represents a comment in commit and issue page.
type Comment struct {
	Id       int64
	Type     CommentType
	PosterId int64
	Poster   *User `xorm:"-"`
	IssueId  int64
	CommitId int64
	Line     int64
	Content  string    `xorm:"TEXT"`
	Created  time.Time `xorm:"CREATED"`
}

// CreateComment creates comment of issue or commit.
func CreateComment(userId, repoId, issueId, commitId, line int64, cmtType CommentType, content string, attachments []int64) (*Comment, error) {
	sess := x.NewSession()
	defer sessionRelease(sess)
	if err := sess.Begin(); err != nil {
		return nil, err
	}

	comment := &Comment{PosterId: userId, Type: cmtType, IssueId: issueId,
		CommitId: commitId, Line: line, Content: content}

	if _, err := sess.Insert(comment); err != nil {
		return nil, err
	}

	// Check comment type.
	switch cmtType {
	case COMMENT_TYPE_COMMENT:
		rawSql := "UPDATE `issue` SET num_comments = num_comments + 1 WHERE id = ?"
		if _, err := sess.Exec(rawSql, issueId); err != nil {
			return nil, err
		}

		if len(attachments) > 0 {
			rawSql = "UPDATE `attachment` SET comment_id = ? WHERE id IN (?)"

			astrs := make([]string, 0, len(attachments))

			for _, a := range attachments {
				astrs = append(astrs, strconv.FormatInt(a, 10))
			}

			if _, err := sess.Exec(rawSql, comment.Id, strings.Join(astrs, ",")); err != nil {
				return nil, err
			}
		}
	case COMMENT_TYPE_REOPEN:
		rawSql := "UPDATE `repository` SET num_closed_issues = num_closed_issues - 1 WHERE id = ?"
		if _, err := sess.Exec(rawSql, repoId); err != nil {
			return nil, err
		}
	case COMMENT_TYPE_CLOSE:
		rawSql := "UPDATE `repository` SET num_closed_issues = num_closed_issues + 1 WHERE id = ?"
		if _, err := sess.Exec(rawSql, repoId); err != nil {
			return nil, err
		}
	}

	return comment, sess.Commit()
}

// GetCommentById returns the comment with the given id
func GetCommentById(commentId int64) (*Comment, error) {
	c := &Comment{Id: commentId}
	_, err := x.Get(c)

	return c, err
}

func (c *Comment) ContentHtml() template.HTML {
	return template.HTML(c.Content)
}

// GetIssueComments returns list of comment by given issue id.
func GetIssueComments(issueId int64) ([]Comment, error) {
	comments := make([]Comment, 0, 10)
	err := x.Asc("created").Find(&comments, &Comment{IssueId: issueId})
	return comments, err
}

// Attachments returns the attachments for this comment.
func (c *Comment) Attachments() []*Attachment {
	a, _ := GetAttachmentsByComment(c.Id)
	return a
}

func (c *Comment) AfterDelete() {
	_, err := DeleteAttachmentsByComment(c.Id, true)

	if err != nil {
		log.Info("Could not delete files for comment %d on issue #%d: %s", c.Id, c.IssueId, err)
	}
}

type Attachment struct {
	Id        int64
	IssueId   int64
	CommentId int64
	Name      string
	Path      string    `xorm:"TEXT"`
	Created   time.Time `xorm:"CREATED"`
}

// CreateAttachment creates a new attachment inside the database and
func CreateAttachment(issueId, commentId int64, name, path string) (*Attachment, error) {
	sess := x.NewSession()
	defer sess.Close()

	if err := sess.Begin(); err != nil {
		return nil, err
	}

	a := &Attachment{IssueId: issueId, CommentId: commentId, Name: name, Path: path}

	if _, err := sess.Insert(a); err != nil {
		sess.Rollback()
		return nil, err
	}

	return a, sess.Commit()
}

// Attachment returns the attachment by given ID.
func GetAttachmentById(id int64) (*Attachment, error) {
	m := &Attachment{Id: id}

	has, err := x.Get(m)

	if err != nil {
		return nil, err
	}

	if !has {
		return nil, ErrAttachmentNotExist
	}

	return m, nil
}

func GetAttachmentsForIssue(issueId int64) ([]*Attachment, error) {
	attachments := make([]*Attachment, 0, 10)
	err := x.Where("issue_id = ?", issueId).And("comment_id = 0").Find(&attachments)
	return attachments, err
}

// GetAttachmentsByIssue returns a list of attachments for the given issue
func GetAttachmentsByIssue(issueId int64) ([]*Attachment, error) {
	attachments := make([]*Attachment, 0, 10)
	err := x.Where("issue_id = ?", issueId).And("comment_id > 0").Find(&attachments)
	return attachments, err
}

// GetAttachmentsByComment returns a list of attachments for the given comment
func GetAttachmentsByComment(commentId int64) ([]*Attachment, error) {
	attachments := make([]*Attachment, 0, 10)
	err := x.Where("comment_id = ?", commentId).Find(&attachments)
	return attachments, err
}

// DeleteAttachment deletes the given attachment and optionally the associated file.
func DeleteAttachment(a *Attachment, remove bool) error {
	_, err := DeleteAttachments([]*Attachment{a}, remove)
	return err
}

// DeleteAttachments deletes the given attachments and optionally the associated files.
func DeleteAttachments(attachments []*Attachment, remove bool) (int, error) {
	for i, a := range attachments {
		if remove {
			if err := os.Remove(a.Path); err != nil {
				return i, err
			}
		}

		if _, err := x.Delete(a.Id); err != nil {
			return i, err
		}
	}

	return len(attachments), nil
}

// DeleteAttachmentsByIssue deletes all attachments associated with the given issue.
func DeleteAttachmentsByIssue(issueId int64, remove bool) (int, error) {
	attachments, err := GetAttachmentsByIssue(issueId)

	if err != nil {
		return 0, err
	}

	return DeleteAttachments(attachments, remove)
}

// DeleteAttachmentsByComment deletes all attachments associated with the given comment.
func DeleteAttachmentsByComment(commentId int64, remove bool) (int, error) {
	attachments, err := GetAttachmentsByComment(commentId)

	if err != nil {
		return 0, err
	}

	return DeleteAttachments(attachments, remove)
}