Move convert package to services (#22264)

Addition to #22256

The `convert` package relies heavily on different models which is
[disallowed by our definition of
modules](https://github.com/go-gitea/gitea/blob/main/CONTRIBUTING.md#design-guideline).
This helps to prevent possible import cycles.

Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>

services/convert/user.go

@@ -0,0 +1,106 @@
+// Copyright 2020 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package convert
+
+import (
+	"code.gitea.io/gitea/models/perm"
+	user_model "code.gitea.io/gitea/models/user"
+	api "code.gitea.io/gitea/modules/structs"
+)
+
+// ToUser convert user_model.User to api.User
+// if doer is set, private information is added if the doer has the permission to see it
+func ToUser(user, doer *user_model.User) *api.User {
+	if user == nil {
+		return nil
+	}
+	authed := false
+	signed := false
+	if doer != nil {
+		signed = true
+		authed = doer.ID == user.ID || doer.IsAdmin
+	}
+	return toUser(user, signed, authed)
+}
+
+// ToUsers convert list of user_model.User to list of api.User
+func ToUsers(doer *user_model.User, users []*user_model.User) []*api.User {
+	result := make([]*api.User, len(users))
+	for i := range users {
+		result[i] = ToUser(users[i], doer)
+	}
+	return result
+}
+
+// ToUserWithAccessMode convert user_model.User to api.User
+// AccessMode is not none show add some more information
+func ToUserWithAccessMode(user *user_model.User, accessMode perm.AccessMode) *api.User {
+	if user == nil {
+		return nil
+	}
+	return toUser(user, accessMode != perm.AccessModeNone, false)
+}
+
+// toUser convert user_model.User to api.User
+// signed shall only be set if requester is logged in. authed shall only be set if user is site admin or user himself
+func toUser(user *user_model.User, signed, authed bool) *api.User {
+	result := &api.User{
+		ID:          user.ID,
+		UserName:    user.Name,
+		FullName:    user.FullName,
+		Email:       user.GetEmail(),
+		AvatarURL:   user.AvatarLink(),
+		Created:     user.CreatedUnix.AsTime(),
+		Restricted:  user.IsRestricted,
+		Location:    user.Location,
+		Website:     user.Website,
+		Description: user.Description,
+		// counter's
+		Followers:    user.NumFollowers,
+		Following:    user.NumFollowing,
+		StarredRepos: user.NumStars,
+	}
+
+	result.Visibility = user.Visibility.String()
+
+	// hide primary email if API caller is anonymous or user keep email private
+	if signed && (!user.KeepEmailPrivate || authed) {
+		result.Email = user.Email
+	}
+
+	// only site admin will get these information and possibly user himself
+	if authed {
+		result.IsAdmin = user.IsAdmin
+		result.LoginName = user.LoginName
+		result.LastLogin = user.LastLoginUnix.AsTime()
+		result.Language = user.Language
+		result.IsActive = user.IsActive
+		result.ProhibitLogin = user.ProhibitLogin
+	}
+	return result
+}
+
+// User2UserSettings return UserSettings based on a user
+func User2UserSettings(user *user_model.User) api.UserSettings {
+	return api.UserSettings{
+		FullName:      user.FullName,
+		Website:       user.Website,
+		Location:      user.Location,
+		Language:      user.Language,
+		Description:   user.Description,
+		Theme:         user.Theme,
+		HideEmail:     user.KeepEmailPrivate,
+		HideActivity:  user.KeepActivityPrivate,
+		DiffViewStyle: user.DiffViewStyle,
+	}
+}
+
+// ToUserAndPermission return User and its collaboration permission for a repository
+func ToUserAndPermission(user, doer *user_model.User, accessMode perm.AccessMode) api.RepoCollaboratorPermission {
+	return api.RepoCollaboratorPermission{
+		User:       ToUser(user, doer),
+		Permission: accessMode.String(),
+		RoleName:   accessMode.String(),
+	}
+}