unit history added

backend/migrate_add_unit_history.py

@@ -0,0 +1,78 @@
+"""
+Migration script to add unit history timeline support.
+
+This creates the unit_history table to track all changes to units:
+- Note changes (archived old notes, new notes)
+- Deployment status changes (deployed/benched)
+- Retired status changes
+- Other field changes
+
+Run this script once to migrate an existing database.
+"""
+
+import sqlite3
+import os
+
+# Database path
+DB_PATH = "./data/seismo_fleet.db"
+
+def migrate_database():
+    """Create the unit_history table"""
+
+    if not os.path.exists(DB_PATH):
+        print(f"Database not found at {DB_PATH}")
+        print("The database will be created automatically when you run the application.")
+        return
+
+    print(f"Migrating database: {DB_PATH}")
+
+    conn = sqlite3.connect(DB_PATH)
+    cursor = conn.cursor()
+
+    # Check if unit_history table already exists
+    cursor.execute("SELECT name FROM sqlite_master WHERE type='table' AND name='unit_history'")
+    if cursor.fetchone():
+        print("Migration already applied - unit_history table exists")
+        conn.close()
+        return
+
+    print("Creating unit_history table...")
+
+    try:
+        cursor.execute("""
+            CREATE TABLE unit_history (
+                id INTEGER PRIMARY KEY AUTOINCREMENT,
+                unit_id TEXT NOT NULL,
+                change_type TEXT NOT NULL,
+                field_name TEXT,
+                old_value TEXT,
+                new_value TEXT,
+                changed_at TIMESTAMP NOT NULL,
+                source TEXT DEFAULT 'manual',
+                notes TEXT
+            )
+        """)
+        print("  ✓ Created unit_history table")
+
+        # Create indexes for better query performance
+        cursor.execute("CREATE INDEX idx_unit_history_unit_id ON unit_history(unit_id)")
+        print("  ✓ Created index on unit_id")
+
+        cursor.execute("CREATE INDEX idx_unit_history_changed_at ON unit_history(changed_at)")
+        print("  ✓ Created index on changed_at")
+
+        conn.commit()
+        print("\nMigration completed successfully!")
+        print("Units will now track their complete history of changes.")
+
+    except sqlite3.Error as e:
+        print(f"\nError during migration: {e}")
+        conn.rollback()
+        raise
+
+    finally:
+        conn.close()
+
+
+if __name__ == "__main__":
+    migrate_database()