"""Migration 0004 — create raw SQLite table ``tls_ref_data``.

Replaces the ``TlsDB.csv`` reference file with a proper SQLite table.
The table stores TLS field-code metadata: human-readable meaning and
data type for each field code used in TLS flow data.
"""

from django.db import migrations

# Raw SQL for creating the tls_ref_data table
CREATE_TLS_REF_DATA = """
CREATE TABLE IF NOT EXISTS tls_ref_data (
    id          INTEGER PRIMARY KEY AUTOINCREMENT,
    field_code  TEXT    NOT NULL UNIQUE,
    meaning     TEXT    NOT NULL DEFAULT '',
    data_type   TEXT    NOT NULL DEFAULT ''
);
"""

DROP_TLS_REF_DATA = """
DROP TABLE IF EXISTS tls_ref_data;
"""


class Migration(migrations.Migration):
    """Create ``tls_ref_data`` table via raw SQL — no Django model needed."""

    dependencies = [
        ('tianxuan_analysis', '0003_analysisrun_sqlite_table'),
    ]

    operations = [
        migrations.RunSQL(
            sql=CREATE_TLS_REF_DATA,
            reverse_sql=DROP_TLS_REF_DATA,
            state_operations=None,
        ),
    ]