"""Pure, offline tests for target_revenue.metrics (WP-0006-T05).

No Docker/Postgres required — metrics.compute_metrics is a pure function
of (manifest, entries, as_of), like fold.py (TSD §6.1).
"""

from __future__ import annotations

from datetime import datetime, timezone

from conftest import golden_entries, golden_manifest

from target_revenue import metrics


def test_mandatory_facts_present_for_golden_phase():
    manifest = golden_manifest()
    entries = golden_entries()
    as_of = datetime(2026, 12, 1, tzinfo=timezone.utc)

    result = metrics.compute_metrics(manifest, entries, as_of)

    facts = result["facts"]
    assert facts["initial_target_amount"] == manifest["phase"]["initial_target"]["amount"]
    assert facts["initial_target_currency"] == manifest["phase"]["initial_target"]["currency"]
    assert facts["last_ledger_entry_id"] == entries[-1]["id"]
    assert facts["longstop_at"] == manifest["phase"]["longstop_at"]
    assert "cumulative_development_credit" in facts
    assert "cumulative_remission_credit" in facts
    assert "outstanding_target" in facts
    assert "is_converted" in facts


def test_calculations_and_forecast_are_separately_labeled():
    manifest = golden_manifest()
    entries = golden_entries()
    as_of = datetime(2026, 12, 1, tzinfo=timezone.utc)

    result = metrics.compute_metrics(manifest, entries, as_of)

    assert set(result.keys()) == {"phase", "as_of", "facts", "calculations", "forecasts"}
    assert "target_satisfaction_percentage" in result["calculations"]
    assert "projected_conversion_date" in result["forecasts"]
    # A forecast must never appear inside the facts block.
    assert "projected_conversion_date" not in result["facts"]


def test_target_satisfaction_percentage_matches_fold():
    manifest = golden_manifest()
    entries = golden_entries()
    as_of = datetime(2026, 12, 1, tzinfo=timezone.utc)

    result = metrics.compute_metrics(manifest, entries, as_of)
    facts = result["facts"]
    initial = facts["initial_target_amount"]
    expected_pct = round(
        100.0
        * min(
            1.0,
            (facts["cumulative_development_credit"] + facts["cumulative_remission_credit"])
            / initial,
        ),
        4,
    )
    assert result["calculations"]["target_satisfaction_percentage"] == expected_pct


def test_no_material_entries_yields_no_velocity_or_forecast():
    manifest = golden_manifest()
    as_of = datetime(2026, 12, 1, tzinfo=timezone.utc)

    result = metrics.compute_metrics(manifest, [], as_of)

    assert result["calculations"]["development_credit_velocity_per_day"] is None
    assert result["calculations"]["remission_credit_velocity_per_day"] is None
    assert result["calculations"]["days_since_last_material_progress"] is None
    assert result["forecasts"]["projected_conversion_date"] is None
    assert result["facts"]["outstanding_target"] == manifest["phase"]["initial_target"]["amount"]


def test_converted_phase_has_no_forecast():
    manifest = golden_manifest()
    entries = golden_entries()
    as_of = datetime(2026, 12, 1, tzinfo=timezone.utc)
    result = metrics.compute_metrics(manifest, entries, as_of)
    if result["facts"]["is_converted"]:
        assert result["forecasts"]["projected_conversion_date"] is None


def test_as_of_must_be_timezone_aware():
    manifest = golden_manifest()
    entries = golden_entries()
    import pytest

    with pytest.raises(ValueError):
        metrics.compute_metrics(manifest, entries, datetime(2026, 12, 1))