Usernames are now case-insensitive

This fixes a UX issue, where if you accidentally capitalized a letter
in the username when logging in, it would instead create a new account.

The behavior was confusing, since to the user it looks as if their
characters were deleted or progress was not saved.

In order for this to work, duplicate accounts (e.g. username and USERNAME)
need to be deleted/renamed. The server will *detect* if any duplicates
exist. If any are found, it will direct the server operator to a pruning
script, or they can choose to resolve the duplicates manually.

Author: CakeLancelot

sql/migration3.sql

@@ -0,0 +1,28 @@
+/*
+    It is recommended in the SQLite manual to turn off
+    foreign keys when making schema changes that involve them
+*/
+PRAGMA foreign_keys=OFF;
+BEGIN TRANSACTION;
+-- Change username column (Login) to be case-insensitive
+CREATE TABLE Temp (
+    AccountID    INTEGER NOT NULL,
+    Login        TEXT    NOT NULL UNIQUE COLLATE NOCASE,
+    Password     TEXT    NOT NULL,
+    Selected     INTEGER  DEFAULT 1 NOT NULL,
+    AccountLevel INTEGER NOT NULL,
+    Created      INTEGER DEFAULT (strftime('%s', 'now')) NOT NULL,
+    LastLogin    INTEGER DEFAULT (strftime('%s', 'now')) NOT NULL,
+    BannedUntil  INTEGER DEFAULT 0 NOT NULL,
+    BannedSince  INTEGER DEFAULT 0 NOT NULL,
+    BanReason    TEXT    DEFAULT '' NOT NULL,
+    PRIMARY KEY(AccountID AUTOINCREMENT)
+);
+INSERT INTO Temp SELECT * FROM Accounts;
+DROP TABLE Accounts;
+ALTER TABLE Temp RENAME TO Accounts;
+-- Update DB Version
+UPDATE Meta SET Value = 4 WHERE Key = 'DatabaseVersion';
+UPDATE Meta SET Value = strftime('%s', 'now') WHERE Key = 'LastMigration';
+COMMIT;
+PRAGMA foreign_keys=ON;

sql/tables.sql

@@ -1,6 +1,6 @@
 CREATE TABLE IF NOT EXISTS Accounts (
     AccountID    INTEGER NOT NULL,
-    Login        TEXT    NOT NULL UNIQUE,
+    Login        TEXT    NOT NULL UNIQUE COLLATE NOCASE,
     Password     TEXT    NOT NULL,
     Selected     INTEGER  DEFAULT 1 NOT NULL,
     AccountLevel INTEGER NOT NULL,

src/db/Database.hpp

@@ -5,7 +5,7 @@
 #include <string>
 #include <vector>
 
-#define DATABASE_VERSION 3
+#define DATABASE_VERSION 4
 
 namespace Database {
 

src/db/init.cpp

@@ -9,6 +9,37 @@
 std::mutex dbCrit;
 sqlite3 *db;
 
+/*
+ * When migrating from DB version 3 to 4, we change the username column
+ * to be case-insensitive. This function ensures there aren't any
+ * duplicates, e.g. username and USERNAME, before doing the migration.
+ * I handled this in the code itself rather than the migration file just so
+ * we can have a more detailed error message than what SQLite provides.
+ */
+static void checkCaseSensitiveDupes() {
+    const char* sql = "SELECT Login, COUNT(*) FROM Accounts GROUP BY LOWER(Login) HAVING COUNT(*) > 1;";
+
+    sqlite3_stmt* stmt;
+    sqlite3_prepare_v2(db, sql, -1, &stmt, NULL);
+    int stat = sqlite3_step(stmt);
+
+    if (stat == SQLITE_DONE) {
+        // no rows returned, so we're good
+        sqlite3_finalize(stmt);
+        return;
+    } else if (stat != SQLITE_ROW) {
+        std::cout << "[FATAL] Failed to check for duplicate accounts: " << sqlite3_errmsg(db) << std::endl;
+        sqlite3_finalize(stmt);
+        exit(1);
+    }
+
+    std::cout << "[FATAL] Case-sensitive duplicates detected in the Login column." << std::endl;
+    std::cout << "Either manually delete/rename the offending accounts, or run the pruning script:" << std::endl;
+    std::cout << "https://github.com/OpenFusionProject/scripts/tree/main/db_migration/caseinsens.py" << std::endl;
+    sqlite3_finalize(stmt);
+    exit(1);
+}
+
 static void createMetaTable() {
     std::lock_guard<std::mutex> lock(dbCrit); // XXX
 
@@ -143,6 +174,10 @@ static void checkMetaTable() {
     }
 
     while (dbVersion != DATABASE_VERSION) {
+        // need to run this before we do any migration logic
+        if (dbVersion == 3)
+            checkCaseSensitiveDupes();
+
         // db migrations
         std::cout << "[INFO] Migrating Database to Version " << dbVersion + 1 << std::endl;