From dcf12634d41ccbfc54953293f2832d1f7c5f34a2 Mon Sep 17 00:00:00 2001
From: Vladimir Simakhin <vsimakhin@gmail.com>
Date: Fri, 13 Dec 2024 09:51:36 +0100
Subject: [PATCH] add shcema version and check to exclude recreate views on
 every start up

---
 internal/driver/db_structure.go |  8 ++++
 internal/driver/driver.go       | 74 ++++++++++++++++++++++++++-------
 2 files changed, 67 insertions(+), 15 deletions(-)

diff --git a/internal/driver/db_structure.go b/internal/driver/db_structure.go
index 6ed5725..5d8214c 100644
--- a/internal/driver/db_structure.go
+++ b/internal/driver/db_structure.go
@@ -1,6 +1,8 @@
 package driver
 
 var (
+	schemaVersion = "2.0.1"
+
 	UUID      = ColumnType{SQLite: "TEXT", MySQL: "VARCHAR(36)"}
 	DateTime  = ColumnType{SQLite: "TEXT", MySQL: "VARCHAR(10)"}
 	SmallText = ColumnType{SQLite: "TEXT", MySQL: "VARCHAR(255)"}
@@ -12,6 +14,12 @@ var (
 	Blob      = ColumnType{SQLite: "BLOB", MySQL: "LONGBLOB"}
 )
 
+var metadataTable = NewTable("metadata", "id", ColumnType{SQLite: "INTEGER", MySQL: "INT UNSIGNED AUTO_INCREMENT"},
+	[]Column{
+		{Name: "version", Type: ColumnType{SQLite: "VARCHAR(32)", MySQL: "VARCHAR(32)"}, Properties: "NOT NULL"},
+		{Name: "created_at", Type: DateTime},
+	})
+
 var logbookTable = NewTable("logbook", "uuid", UUID,
 	[]Column{
 		{Name: "date", Type: DateTime, Properties: "NOT NULL"},
diff --git a/internal/driver/driver.go b/internal/driver/driver.go
index ef2fbae..cd1cd93 100644
--- a/internal/driver/driver.go
+++ b/internal/driver/driver.go
@@ -4,6 +4,7 @@ import (
 	"context"
 	"database/sql"
 	"encoding/json"
+	"fmt"
 	"time"
 
 	_ "embed"
@@ -39,32 +40,75 @@ func OpenDB(engine string, dsn string) (*sql.DB, error) {
 
 // validateDB creates db structure in case it's a first run and the schema is empty
 func validateDB(db *sql.DB, engine string) error {
-	// check tables
-	tables := []*Table{logbookTable, airportsTable, customAirportsTable,
-		settingsTable, licensingTable, attachmentsTable, sessionsTable,
-	}
+	metadataTable.initTable(db, engine)
+	isNewSchema := newShema(db)
+	if isNewSchema {
+		// check tables
+		tables := []*Table{logbookTable, airportsTable, customAirportsTable,
+			settingsTable, licensingTable, attachmentsTable, sessionsTable,
+		}
+
+		for _, table := range tables {
+			if err := table.initTable(db, engine); err != nil {
+				return err
+			}
+		}
+
+		// check views
+		views := []*View{logbookView, airportsView}
+		for _, view := range views {
+			if err := view.initView(db, engine); err != nil {
+				return err
+			}
+		}
 
-	for _, table := range tables {
-		if err := table.initTable(db, engine); err != nil {
+		// check settings table it's not empty
+		err := checkSettingsTable(db)
+		if err != nil {
 			return err
 		}
-	}
 
-	// check views
-	views := []*View{logbookView, airportsView}
-	for _, view := range views {
-		if err := view.initView(db, engine); err != nil {
+		// update schema version
+		err = updateSchemaVersion(db)
+		if err != nil {
 			return err
 		}
 	}
 
-	// check settings table it's not empty
-	err := checkSettingsTable(db)
+	return nil
+}
+
+func newShema(db *sql.DB) bool {
+	ctx, cancel := context.WithTimeout(context.Background(), 60*time.Second)
+	defer cancel()
+
+	query := "SELECT version FROM metadata ORDER BY created_at DESC LIMIT 1"
+	var version string
+	err := db.QueryRowContext(ctx, query).Scan(&version)
 	if err != nil {
-		return err
+		if err == sql.ErrNoRows {
+			fmt.Printf("No rows found in 'metadata'. Initializing version %s...\n", schemaVersion)
+			return true
+		}
+		fmt.Println(err)
+		return true
 	}
 
-	return nil
+	if version != schemaVersion {
+		fmt.Printf("Schema version (%s) mismatch. Initializing version %s...\n", version, schemaVersion)
+		return true
+	}
+
+	return false
+}
+
+func updateSchemaVersion(db *sql.DB) error {
+	ctx, cancel := context.WithTimeout(context.Background(), 60*time.Second)
+	defer cancel()
+
+	query := "INSERT INTO metadata (version, created_at) VALUES (?,?)"
+	_, err := db.ExecContext(ctx, query, schemaVersion, time.Now().Format("02.01.2006 15:04:05"))
+	return err
 }
 
 // checkSettingsTable verifies the proper transition to the new settings table