import pytest

from app.core.orchestration.migration.reconciliation import (
    ExecutionSnapshot,
    ReconciliationPolicy,
    WorkflowReconciler,
)


def snapshot(
    *,
    engine,
    execution_id,
    content_hash="content-a",
    amount_sum=30.0,
    duration=12.0,
    partition_duration=None,
    cpu_seconds=2.0,
):
    partition_duration = (
        duration if partition_duration is None else partition_duration
    )
    return ExecutionSnapshot.from_dict(
        {
            "engine": engine,
            "execution_id": execution_id,
            "status": "success",
            "duration_seconds": duration,
            "resource_usage": {
                "cpu_seconds": cpu_seconds,
                "peak_memory_mb": 128.0,
            },
            "nodes": {
                "read_orders": {
                    "partitions": {
                        "2026-07-19": {
                            "row_count": 2,
                            "primary_keys_hash": "keys-a",
                            "content_hash": content_hash,
                            "error_count": 0,
                            "duration_seconds": partition_duration,
                            "resource_usage": {"rows_scanned": 2},
                            "aggregates": {
                                "amount_sum": amount_sum,
                                "generated_epoch": 1000,
                            },
                        }
                    }
                }
            },
        }
    )


def test_equivalent_runs_pass_all_core_dimensions_without_raw_rows():
    report = WorkflowReconciler().compare(
        snapshot(engine="n8n", execution_id="n8n-1"),
        snapshot(engine="kestra", execution_id="kestra-1"),
        ReconciliationPolicy(),
    )

    assert report["status"] == "passed"
    assert report["equivalent"] is True
    assert report["difference_count"] == 0
    assert report["metrics"]["compared_partitions"] == 1
    assert report["metrics"]["row_count_delta"] == 0
    assert "rows" not in repr(report).lower()


def test_report_locates_hash_and_aggregate_difference_to_node_partition():
    report = WorkflowReconciler().compare(
        snapshot(engine="n8n", execution_id="n8n-1"),
        snapshot(
            engine="kestra",
            execution_id="kestra-1",
            content_hash="content-b",
            amount_sum=32.0,
        ),
        ReconciliationPolicy(
            numeric_tolerances={
                "nodes.*.partitions.*.aggregates.amount_sum": 0.5
            }
        ),
    )

    assert report["status"] == "failed"
    assert report["equivalent"] is False
    assert {
        (
            difference["node_id"],
            difference["partition"],
            difference["metric"],
        )
        for difference in report["differences"]
    } >= {
        ("read_orders", "2026-07-19", "content_hash"),
        ("read_orders", "2026-07-19", "aggregates.amount_sum"),
    }


def test_explicit_tolerance_and_nondeterministic_ignore_can_pass():
    policy = ReconciliationPolicy(
        ignored_paths={
            "duration_seconds",
            "resource_usage.cpu_seconds",
            "nodes.*.partitions.*.duration_seconds",
            "nodes.*.partitions.*.aggregates.generated_epoch",
        },
        numeric_tolerances={
            "nodes.*.partitions.*.aggregates.amount_sum": 0.1
        },
    )
    report = WorkflowReconciler().compare(
        snapshot(engine="n8n", execution_id="n8n-1"),
        snapshot(
            engine="kestra",
            execution_id="kestra-1",
            amount_sum=30.05,
            duration=30.0,
            cpu_seconds=5.0,
        ),
        policy,
    )

    assert report["status"] == "passed"
    assert report["policy"]["ignored_paths"] == sorted(policy.ignored_paths)
    assert report["policy"]["numeric_tolerances"] == {
        "nodes.*.partitions.*.aggregates.amount_sum": 0.1
    }


@pytest.mark.parametrize(
    "path",
    [
        "status",
        "nodes.*.partitions.*.row_count",
        "nodes.*.partitions.*.primary_keys_hash",
        "nodes.*.partitions.*.content_hash",
        "nodes.*.partitions.*.error_count",
        "nodes.read_orders.partitions.2026-07-19.row_count",
        "nodes.*.partitions.*",
    ],
)
def test_policy_cannot_ignore_core_correctness_metrics(path):
    with pytest.raises(ValueError, match="core reconciliation metric"):
        ReconciliationPolicy(ignored_paths={path})


def test_partition_duration_is_reconciled_independently():
    report = WorkflowReconciler().compare(
        snapshot(engine="n8n", execution_id="n8n-1"),
        snapshot(
            engine="kestra",
            execution_id="kestra-1",
            partition_duration=15.0,
        ),
        ReconciliationPolicy(),
    )

    assert {
        difference["metric"] for difference in report["differences"]
    } == {"duration_seconds"}
    assert report["differences"][0]["node_id"] == "read_orders"


def test_missing_partition_is_reported_without_silent_truncation():
    baseline = snapshot(engine="n8n", execution_id="n8n-1")
    candidate = snapshot(engine="kestra", execution_id="kestra-1")
    candidate.nodes["read_orders"]["partitions"] = {}

    report = WorkflowReconciler().compare(
        baseline,
        candidate,
        ReconciliationPolicy(),
    )

    assert report["status"] == "failed"
    assert report["differences"] == [
        {
            "node_id": "read_orders",
            "partition": "2026-07-19",
            "metric": "partition_presence",
            "baseline": True,
            "candidate": False,
        }
    ]
    assert report["metrics"]["row_count_delta"] == -2