From 05d3d7d554458a14df8c41571ffdab54bdbf625a Mon Sep 17 00:00:00 2001
From: Frank Elsinga <frank@elsinga.de>
Date: Sat, 26 Aug 2023 20:08:32 +0200
Subject: [PATCH] removed the chat from the database

---
 server/backend/migration/20230825000000.go | 85 ++++++++++++++++++++++
 1 file changed, 85 insertions(+)
 create mode 100644 server/backend/migration/20230825000000.go

diff --git a/server/backend/migration/20230825000000.go b/server/backend/migration/20230825000000.go
new file mode 100644
index 00000000..22885c5c
--- /dev/null
+++ b/server/backend/migration/20230825000000.go
@@ -0,0 +1,85 @@
+package migration
+
+import (
+	"github.com/TUM-Dev/Campus-Backend/server/model"
+	"github.com/go-gormigrate/gormigrate/v2"
+	"gorm.io/gorm"
+)
+
+type device2stats struct {
+	ChatRoomsActivity  int `gorm:"column:ChatRoomsActivity;default 0;not null"`
+	ChatActivity       int `gorm:"column:ChatActivity;default 0;not null"`
+	WizNavChatActivity int `gorm:"column:WizNavChatActivity;default 0;not null"`
+}
+
+// migrate20230825000000
+// Removes all traces of the chat from the database.
+func (m TumDBMigrator) migrate20230825000000() *gormigrate.Migration {
+	return &gormigrate.Migration{
+		ID: "20230825000000",
+		Migrate: func(tx *gorm.DB) error {
+			// deactivete the crontab (Rollback deletes this from the enum)
+			// given that previously, not cronjobs for this type existed there is no need to remove offending entries first
+			if err := SafeEnumRollback(tx, &model.Crontab{}, "type", "chat"); err != nil {
+				return err
+			}
+
+			// Remove tracking from device2stats
+			if err := tx.Migrator().DropColumn(&device2stats{}, "ChatRoomsActivity"); err != nil {
+				return err
+			}
+			if err := tx.Migrator().DropColumn(&device2stats{}, "ChatActivity"); err != nil {
+				return err
+			}
+			if err := tx.Migrator().DropColumn(&device2stats{}, "WizNavChatActivity"); err != nil {
+				return err
+			}
+
+			// Delete all tables
+			if err := tx.Migrator().DropTable("chat_message"); err != nil {
+				return err
+			}
+			if err := tx.Migrator().DropTable("chat_room2members"); err != nil {
+				return err
+			}
+			return tx.Migrator().DropTable("chat_room")
+		},
+		Rollback: func(tx *gorm.DB) error {
+			// Restore chat_room
+			if err := tx.Exec("create table chat_room(room int auto_increment primary key, name varchar(100) not null, semester varchar(3) null, constraint `Index 2` unique (semester, name));").Error; err != nil {
+				return err
+			}
+
+			// Add tracking from device2stats
+			if err := tx.Migrator().AutoMigrate(&device2stats{}); err != nil {
+				return err
+			}
+
+			// Restore chat_message
+			if err := tx.Exec("create table chat_message (message int auto_increment primary key, member int not null, room int not null, text longtext not null, created datetime not null, signature longtext not null, constraint FK_chat_message_chat_room foreign key (room) references chat_room (room) on update cascade on delete cascade, constraint chat_message_ibfk_1 foreign key (member) references member (member) on update cascade on delete cascade);").Error; err != nil {
+				return err
+			}
+			if err := tx.Exec("create index chat_message_b3c09425 on chat_message (member);").Error; err != nil {
+				return err
+			}
+			if err := tx.Exec("create index chat_message_ca20ebca on chat_message (room);").Error; err != nil {
+				return err
+			}
+
+			// Restore chat_room2members
+			if err := tx.Exec("create table chat_room2members(room2members int auto_increment primary key, room int not null, member int not null, constraint chatroom_id unique (room, member), constraint FK_chat_room2members_chat_room foreign key (room) references chat_room (room) on update cascade on delete cascade, constraint chat_room2members_ibfk_2 foreign key (member) references member (member) on update cascade on delete cascade );").Error; err != nil {
+				return err
+			}
+			if err := tx.Exec("create index chat_chatroom_members_29801a33 on chat_room2members (room);").Error; err != nil {
+				return err
+			}
+			if err := tx.Exec("create index chat_chatroom_members_b3c09425 on chat_room2members (member);").Error; err != nil {
+				return err
+			}
+
+			// activete the crontab (Migrate adds this from to the enum)
+			// given that previously, not cronjobs for this type existed there is no need to add entries first
+			return SafeEnumMigrate(tx, &model.Crontab{}, "type", "chat")
+		},
+	}
+}