"""Add forward_only column to the snapshots table."""

import json

from sqlglot import exp

from sqlmesh.utils.migration import index_text_type, blob_text_type


def migrate_schemas(engine_adapter, schema, **kwargs):  # type: ignore
    snapshots_table = "_snapshots"
    if schema:
        snapshots_table = f"{schema}.{snapshots_table}"

    alter_table_exp = exp.Alter(
        this=exp.to_table(snapshots_table),
        kind="TABLE",
        actions=[
            exp.ColumnDef(
                this=exp.to_column("forward_only"),
                kind=exp.DataType.build("boolean"),
            )
        ],
    )
    engine_adapter.execute(alter_table_exp)


def migrate_rows(engine_adapter, schema, **kwargs):  # type: ignore
    import pandas as pd

    snapshots_table = "_snapshots"
    if schema:
        snapshots_table = f"{schema}.{snapshots_table}"

    new_snapshots = []

    for (
        name,
        identifier,
        version,
        snapshot,
        kind_name,
        updated_ts,
        unpaused_ts,
        ttl_ms,
        unrestorable,
        forward_only,
    ) in engine_adapter.fetchall(
        exp.select(
            "name",
            "identifier",
            "version",
            "snapshot",
            "kind_name",
            "updated_ts",
            "unpaused_ts",
            "ttl_ms",
            "unrestorable",
            "forward_only",
        ).from_(snapshots_table),
        quote_identifiers=True,
    ):
        parsed_snapshot = json.loads(snapshot)

        forward_only = parsed_snapshot.get("forward_only")
        if forward_only is None:
            forward_only = parsed_snapshot.get("change_category") == 3

        new_snapshots.append(
            {
                "name": name,
                "identifier": identifier,
                "version": version,
                "snapshot": json.dumps(parsed_snapshot),
                "kind_name": kind_name,
                "updated_ts": updated_ts,
                "unpaused_ts": unpaused_ts,
                "ttl_ms": ttl_ms,
                "unrestorable": unrestorable,
                "forward_only": forward_only,
            }
        )

    if new_snapshots:
        engine_adapter.delete_from(snapshots_table, "TRUE")
        index_type = index_text_type(engine_adapter.dialect)
        blob_type = blob_text_type(engine_adapter.dialect)

        engine_adapter.insert_append(
            snapshots_table,
            pd.DataFrame(new_snapshots),
            target_columns_to_types={
                "name": exp.DataType.build(index_type),
                "identifier": exp.DataType.build(index_type),
                "version": exp.DataType.build(index_type),
                "snapshot": exp.DataType.build(blob_type),
                "kind_name": exp.DataType.build(index_type),
                "updated_ts": exp.DataType.build("bigint"),
                "unpaused_ts": exp.DataType.build("bigint"),
                "ttl_ms": exp.DataType.build("bigint"),
                "unrestorable": exp.DataType.build("boolean"),
                "forward_only": exp.DataType.build("boolean"),
            },
        )
