Add API for Issue set Subscription (#8729)

* add issue subscriber API

* subscribers return []user.APIFormat

* add comments

* more meaningfull description

* without "reqToken()" api works ...
 * should be still secure beause ctx.user has to be there or nothing will hapen

* FIX: getIssueWatchers() get only aktive suscriber

* add return avter error on right position

* Revert "FIX: getIssueWatchers() get only aktive suscriber"

This reverts commit 5eca9291858a821981992b0aaa38cef610d84bca.

* Update routers/api/v1/repo/issue.go

Co-Authored-By: guillep2k <18600385+guillep2k@users.noreply.github.com>

* test go linter again

* update swagger

* GetIssueWatchers -> GetIssueSubscribers

part one

Co-Authored-By: guillep2k <18600385+guillep2k@users.noreply.github.com>

* GetIssueWatchers -> GetIssueSubscribers
part two

* Revert "test go linter again"

This reverts commit bab12356227e44334de113b76f12099de0b8aaa6.

* change description for unsubscribe too

* golangci-lint timeout avter 5min

* move issueSubscription to seperate file

* dont create black entitys

* use IsWatching until refactoring

* Update License Info

* better swagger description

* Update .golangci.yml

because functions moved from issue.go to issue_subscription.go

* add IssueWatchList type

* batch tasks

* use e Engien

* add error handling

* error should be the last type when returning multiple items

* short version

* reurn empy UserList instead of nil

7 files changed, 425 insertions, 3 deletions

diff --git a/.golangci.yml b/.golangci.yml
index fd7393372b..121ef583ac 100644
--- a/.golangci.yml
+++ b/.golangci.yml
@@ -73,6 +73,9 @@ issues:
     - path: routers/routes/routes.go
       linters:
         - dupl
+    - path: routers/api/v1/repo/issue_subscription.go
+      linters:
+        - dupl
     - path: routers/repo/view.go
       linters:
         - dupl
diff --git a/Makefile b/Makefile
index ebcfadb21d..34685dea93 100644
--- a/Makefile
+++ b/Makefile
@@ -521,4 +521,4 @@ golangci-lint:
 		export BINARY="golangci-lint"; \
 		curl -sfL https://install.goreleaser.com/github.com/golangci/golangci-lint.sh | sh -s -- -b $(GOPATH)/bin v1.20.0; \
 	fi
-	golangci-lint run
+	golangci-lint run --timeout 5m
diff --git a/models/issue_watch.go b/models/issue_watch.go
index 2f55c6a84d..1ae0c9d474 100644
--- a/models/issue_watch.go
+++ b/models/issue_watch.go
@@ -16,6 +16,9 @@ type IssueWatch struct {
 	UpdatedUnix timeutil.TimeStamp `xorm:"updated NOT NULL"`
 }
 
+// IssueWatchList contains IssueWatch
+type IssueWatchList []*IssueWatch
+
 // CreateOrUpdateIssueWatch set watching for a user and issue
 func CreateOrUpdateIssueWatch(userID, issueID int64, isWatching bool) error {
 	iw, exists, err := getIssueWatch(x, userID, issueID)
@@ -58,11 +61,11 @@ func getIssueWatch(e Engine, userID, issueID int64) (iw *IssueWatch, exists bool
 }
 
 // GetIssueWatchers returns watchers/unwatchers of a given issue
-func GetIssueWatchers(issueID int64) ([]*IssueWatch, error) {
+func GetIssueWatchers(issueID int64) (IssueWatchList, error) {
 	return getIssueWatchers(x, issueID)
 }
 
-func getIssueWatchers(e Engine, issueID int64) (watches []*IssueWatch, err error) {
+func getIssueWatchers(e Engine, issueID int64) (watches IssueWatchList, err error) {
 	err = e.
 		Where("`issue_watch`.issue_id = ?", issueID).
 		And("`user`.is_active = ?", true).
@@ -83,3 +86,29 @@ func removeIssueWatchersByRepoID(e Engine, userID int64, repoID int64) error {
 		Update(iw)
 	return err
 }
+
+// LoadWatchUsers return watching users
+func (iwl IssueWatchList) LoadWatchUsers() (users UserList, err error) {
+	return iwl.loadWatchUsers(x)
+}
+
+func (iwl IssueWatchList) loadWatchUsers(e Engine) (users UserList, err error) {
+	if len(iwl) == 0 {
+		return []*User{}, nil
+	}
+
+	var userIDs = make([]int64, 0, len(iwl))
+	for _, iw := range iwl {
+		if iw.IsWatching {
+			userIDs = append(userIDs, iw.UserID)
+		}
+	}
+
+	if len(userIDs) == 0 {
+		return []*User{}, nil
+	}
+
+	err = e.In("id", userIDs).Find(&users)
+
+	return
+}
diff --git a/models/userlist.go b/models/userlist.go
index a2a4248482..16ec6fee55 100644
--- a/models/userlist.go
+++ b/models/userlist.go
@@ -8,6 +8,7 @@ import (
 	"fmt"
 
 	"code.gitea.io/gitea/modules/log"
+	api "code.gitea.io/gitea/modules/structs"
 )
 
 //UserList is a list of user.
@@ -93,3 +94,12 @@ func (users UserList) loadTwoFactorStatus(e Engine) (map[int64]*TwoFactor, error
 	}
 	return tokenMaps, nil
 }
+
+//APIFormat return list of users in api format
+func (users UserList) APIFormat() []*api.User {
+	var result []*api.User
+	for _, u := range users {
+		result = append(result, u.APIFormat())
+	}
+	return result
+}
diff --git a/routers/api/v1/api.go b/routers/api/v1/api.go
index 1acd849b8d..b68717f7c8 100644
--- a/routers/api/v1/api.go
+++ b/routers/api/v1/api.go
@@ -690,6 +690,11 @@ func RegisterRoutes(m *macaron.Macaron) {
 							m.Post("/start", reqToken(), repo.StartIssueStopwatch)
 							m.Post("/stop", reqToken(), repo.StopIssueStopwatch)
 						})
+						m.Group("/subscriptions", func() {
+							m.Get("", bind(api.User{}), repo.GetIssueSubscribers)
+							m.Put("/:user", repo.AddIssueSubscription)
+							m.Delete("/:user", repo.DelIssueSubscription)
+						})
 					})
 				}, mustEnableIssuesOrPulls)
 				m.Group("/labels", func() {
diff --git a/routers/api/v1/repo/issue_subscription.go b/routers/api/v1/repo/issue_subscription.go
new file mode 100644
index 0000000000..012dcda44f
--- /dev/null
+++ b/routers/api/v1/repo/issue_subscription.go
@@ -0,0 +1,216 @@
+// Copyright 2019 The Gitea 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 repo
+
+import (
+	"code.gitea.io/gitea/models"
+	"code.gitea.io/gitea/modules/context"
+	api "code.gitea.io/gitea/modules/structs"
+)
+
+// AddIssueSubscription Subscribe user to issue
+func AddIssueSubscription(ctx *context.APIContext) {
+	// swagger:operation PUT /repos/{owner}/{repo}/issues/{index}/subscriptions/{user} issue issueAddSubscription
+	// ---
+	// summary: Subscribe user to issue
+	// consumes:
+	// - application/json
+	// produces:
+	// - application/json
+	// parameters:
+	// - name: owner
+	//   in: path
+	//   description: owner of the repo
+	//   type: string
+	//   required: true
+	// - name: repo
+	//   in: path
+	//   description: name of the repo
+	//   type: string
+	//   required: true
+	// - name: index
+	//   in: path
+	//   description: index of the issue
+	//   type: integer
+	//   format: int64
+	//   required: true
+	// - name: user
+	//   in: path
+	//   description: user to subscribe
+	//   type: string
+	//   required: true
+	// responses:
+	//   "201":
+	//     "$ref": "#/responses/empty"
+	//   "304":
+	//     description: User can only subscribe itself if he is no admin
+	//   "404":
+	//     description: Issue not found
+	issue, err := models.GetIssueByIndex(ctx.Repo.Repository.ID, ctx.ParamsInt64(":index"))
+	if err != nil {
+		if models.IsErrIssueNotExist(err) {
+			ctx.NotFound()
+		} else {
+			ctx.Error(500, "GetIssueByIndex", err)
+		}
+
+		return
+	}
+
+	user, err := models.GetUserByName(ctx.Params(":user"))
+	if err != nil {
+		if models.IsErrUserNotExist(err) {
+			ctx.NotFound()
+		} else {
+			ctx.Error(500, "GetUserByName", err)
+		}
+
+		return
+	}
+
+	//only admin and user for itself can change subscription
+	if user.ID != ctx.User.ID && !ctx.User.IsAdmin {
+		ctx.Error(403, "User", nil)
+		return
+	}
+
+	if err := models.CreateOrUpdateIssueWatch(user.ID, issue.ID, true); err != nil {
+		ctx.Error(500, "CreateOrUpdateIssueWatch", err)
+		return
+	}
+
+	ctx.Status(201)
+}
+
+// DelIssueSubscription Unsubscribe user from issue
+func DelIssueSubscription(ctx *context.APIContext) {
+	// swagger:operation DELETE /repos/{owner}/{repo}/issues/{index}/subscriptions/{user} issue issueDeleteSubscription
+	// ---
+	// summary: Unsubscribe user from issue
+	// consumes:
+	// - application/json
+	// produces:
+	// - application/json
+	// parameters:
+	// - name: owner
+	//   in: path
+	//   description: owner of the repo
+	//   type: string
+	//   required: true
+	// - name: repo
+	//   in: path
+	//   description: name of the repo
+	//   type: string
+	//   required: true
+	// - name: index
+	//   in: path
+	//   description: index of the issue
+	//   type: integer
+	//   format: int64
+	//   required: true
+	// - name: user
+	//   in: path
+	//   description: user witch unsubscribe
+	//   type: string
+	//   required: true
+	// responses:
+	//   "201":
+	//     "$ref": "#/responses/empty"
+	//   "304":
+	//     description: User can only subscribe itself if he is no admin
+	//   "404":
+	//     description: Issue not found
+	issue, err := models.GetIssueByIndex(ctx.Repo.Repository.ID, ctx.ParamsInt64(":index"))
+	if err != nil {
+		if models.IsErrIssueNotExist(err) {
+			ctx.NotFound()
+		} else {
+			ctx.Error(500, "GetIssueByIndex", err)
+		}
+
+		return
+	}
+
+	user, err := models.GetUserByName(ctx.Params(":user"))
+	if err != nil {
+		if models.IsErrUserNotExist(err) {
+			ctx.NotFound()
+		} else {
+			ctx.Error(500, "GetUserByName", err)
+		}
+
+		return
+	}
+
+	//only admin and user for itself can change subscription
+	if user.ID != ctx.User.ID && !ctx.User.IsAdmin {
+		ctx.Error(403, "User", nil)
+		return
+	}
+
+	if err := models.CreateOrUpdateIssueWatch(user.ID, issue.ID, false); err != nil {
+		ctx.Error(500, "CreateOrUpdateIssueWatch", err)
+		return
+	}
+
+	ctx.Status(201)
+}
+
+// GetIssueSubscribers return subscribers of an issue
+func GetIssueSubscribers(ctx *context.APIContext, form api.User) {
+	// swagger:operation GET /repos/{owner}/{repo}/issues/{index}/subscriptions issue issueSubscriptions
+	// ---
+	// summary: Get users who subscribed on an issue.
+	// consumes:
+	// - application/json
+	// produces:
+	// - application/json
+	// parameters:
+	// - name: owner
+	//   in: path
+	//   description: owner of the repo
+	//   type: string
+	//   required: true
+	// - name: repo
+	//   in: path
+	//   description: name of the repo
+	//   type: string
+	//   required: true
+	// - name: index
+	//   in: path
+	//   description: index of the issue
+	//   type: integer
+	//   format: int64
+	//   required: true
+	// responses:
+	//   "201":
+	//     "$ref": "#/responses/empty"
+	//   "404":
+	//     description: Issue not found
+	issue, err := models.GetIssueByIndex(ctx.Repo.Repository.ID, ctx.ParamsInt64(":index"))
+	if err != nil {
+		if models.IsErrIssueNotExist(err) {
+			ctx.NotFound()
+		} else {
+			ctx.Error(500, "GetIssueByIndex", err)
+		}
+
+		return
+	}
+
+	iwl, err := models.GetIssueWatchers(issue.ID)
+	if err != nil {
+		ctx.Error(500, "GetIssueWatchers", err)
+		return
+	}
+
+	users, err := iwl.LoadWatchUsers()
+	if err != nil {
+		ctx.Error(500, "LoadWatchUsers", err)
+		return
+	}
+
+	ctx.JSON(200, users.APIFormat())
+}
diff --git a/templates/swagger/v1_json.tmpl b/templates/swagger/v1_json.tmpl
index da7ebda852..41e5353ea7 100644
--- a/templates/swagger/v1_json.tmpl
+++ b/templates/swagger/v1_json.tmpl
@@ -3781,6 +3781,165 @@
         }
       }
     },
+    "/repos/{owner}/{repo}/issues/{index}/subscriptions": {
+      "get": {
+        "consumes": [
+          "application/json"
+        ],
+        "produces": [
+          "application/json"
+        ],
+        "tags": [
+          "issue"
+        ],
+        "summary": "Get users who subscribed on an issue.",
+        "operationId": "issueSubscriptions",
+        "parameters": [
+          {
+            "type": "string",
+            "description": "owner of the repo",
+            "name": "owner",
+            "in": "path",
+            "required": true
+          },
+          {
+            "type": "string",
+            "description": "name of the repo",
+            "name": "repo",
+            "in": "path",
+            "required": true
+          },
+          {
+            "type": "integer",
+            "format": "int64",
+            "description": "index of the issue",
+            "name": "index",
+            "in": "path",
+            "required": true
+          }
+        ],
+        "responses": {
+          "201": {
+            "$ref": "#/responses/empty"
+          },
+          "404": {
+            "description": "Issue not found"
+          }
+        }
+      }
+    },
+    "/repos/{owner}/{repo}/issues/{index}/subscriptions/{user}": {
+      "put": {
+        "consumes": [
+          "application/json"
+        ],
+        "produces": [
+          "application/json"
+        ],
+        "tags": [
+          "issue"
+        ],
+        "summary": "Subscribe user to issue",
+        "operationId": "issueAddSubscription",
+        "parameters": [
+          {
+            "type": "string",
+            "description": "owner of the repo",
+            "name": "owner",
+            "in": "path",
+            "required": true
+          },
+          {
+            "type": "string",
+            "description": "name of the repo",
+            "name": "repo",
+            "in": "path",
+            "required": true
+          },
+          {
+            "type": "integer",
+            "format": "int64",
+            "description": "index of the issue",
+            "name": "index",
+            "in": "path",
+            "required": true
+          },
+          {
+            "type": "string",
+            "description": "user to subscribe",
+            "name": "user",
+            "in": "path",
+            "required": true
+          }
+        ],
+        "responses": {
+          "201": {
+            "$ref": "#/responses/empty"
+          },
+          "304": {
+            "description": "User can only subscribe itself if he is no admin"
+          },
+          "404": {
+            "description": "Issue not found"
+          }
+        }
+      },
+      "delete": {
+        "consumes": [
+          "application/json"
+        ],
+        "produces": [
+          "application/json"
+        ],
+        "tags": [
+          "issue"
+        ],
+        "summary": "Unsubscribe user from issue",
+        "operationId": "issueDeleteSubscription",
+        "parameters": [
+          {
+            "type": "string",
+            "description": "owner of the repo",
+            "name": "owner",
+            "in": "path",
+            "required": true
+          },
+          {
+            "type": "string",
+            "description": "name of the repo",
+            "name": "repo",
+            "in": "path",
+            "required": true
+          },
+          {
+            "type": "integer",
+            "format": "int64",
+            "description": "index of the issue",
+            "name": "index",
+            "in": "path",
+            "required": true
+          },
+          {
+            "type": "string",
+            "description": "user witch unsubscribe",
+            "name": "user",
+            "in": "path",
+            "required": true
+          }
+        ],
+        "responses": {
+          "201": {
+            "$ref": "#/responses/empty"
+          },
+          "304": {
+            "description": "User can only subscribe itself if he is no admin"
+          },
+          "404": {
+            "description": "Issue not found"
+          }
+        }
+      }
+    },
     "/repos/{owner}/{repo}/keys": {
       "get": {
         "produces": [