Jul 8 - Implement issue assignment separation

migrations/versions/phase35_issue_handler_type.py

@@ -0,0 +1,68 @@
+"""phase35 — issue handler_type + facility-staff handler fields
+
+Separates WHO handles an issue into three categories:
+  internal — one of our staff (existing assigned_to User)
+  facility — the facility's own staff (new free-text facility_handler_* fields)
+  vendor   — an external contractor (existing vendor_* fields, phase26)
+
+`assigned_to` remains the internal follow-up owner in all cases.
+
+Backfills existing rows that already have a vendor_name to handler_type='vendor'.
+Uses INFORMATION_SCHEMA column-existence checks — safe to re-run.
+"""
+
+revision      = 'phase35_issue_handler'
+down_revision = 'phase34_facility_qr'
+branch_labels = None
+depends_on    = None
+
+from alembic import op
+import sqlalchemy as sa
+
+
+def _column_exists(conn, table, column):
+    result = conn.execute(sa.text(
+        "SELECT COUNT(*) FROM INFORMATION_SCHEMA.COLUMNS "
+        "WHERE TABLE_SCHEMA = DATABASE() "
+        "AND TABLE_NAME = :t AND COLUMN_NAME = :c"
+    ), {"t": table, "c": column})
+    return result.scalar() > 0
+
+
+def upgrade():
+    bind = op.get_bind()
+
+    if not _column_exists(bind, 'issues', 'handler_type'):
+        op.execute(sa.text(
+            "ALTER TABLE issues ADD COLUMN handler_type "
+            "ENUM('internal','facility','vendor') NOT NULL DEFAULT 'internal'"
+        ))
+
+    if not _column_exists(bind, 'issues', 'facility_handler_name'):
+        op.execute(sa.text(
+            "ALTER TABLE issues ADD COLUMN facility_handler_name VARCHAR(100) NULL"
+        ))
+    if not _column_exists(bind, 'issues', 'facility_handler_contact'):
+        op.execute(sa.text(
+            "ALTER TABLE issues ADD COLUMN facility_handler_contact VARCHAR(200) NULL"
+        ))
+    if not _column_exists(bind, 'issues', 'facility_handler_notes'):
+        op.execute(sa.text(
+            "ALTER TABLE issues ADD COLUMN facility_handler_notes TEXT NULL"
+        ))
+
+    # Backfill: rows already carrying a vendor become handler_type='vendor'
+    # so existing contractor assignments keep their meaning.
+    op.execute(sa.text(
+        "UPDATE issues SET handler_type = 'vendor' "
+        "WHERE handler_type = 'internal' "
+        "AND vendor_name IS NOT NULL AND TRIM(vendor_name) <> ''"
+    ))
+
+
+def downgrade():
+    bind = op.get_bind()
+    for col in ('facility_handler_notes', 'facility_handler_contact',
+                'facility_handler_name', 'handler_type'):
+        if _column_exists(bind, 'issues', col):
+            op.execute(sa.text(f"ALTER TABLE issues DROP COLUMN {col}"))