"""Unit tests for the subscription tier utility module."""

import pytest
from sqlalchemy import create_engine
from sqlalchemy.orm import sessionmaker
from unittest.mock import MagicMock, patch
from datetime import datetime, timezone, date

from app.utils.subscription import (
    TIERS,
    TIER_ORDER,
    DEFAULT_TIER,
    get_tier,
    get_all_tiers,
    get_user_tier_id,
    get_user_usage,
    check_upload_allowed,
    QuotaExceeded,
    get_lifetime_file_count,
    get_today_file_count,
    get_month_file_count,
)


# ---------------------------------------------------------------------------
# Basic catalogue tests
# ---------------------------------------------------------------------------


@pytest.mark.unit
def test_all_tiers_present():
    """All four tier IDs must exist."""
    for tid in ["free", "starter", "professional", "business"]:
        assert tid in TIERS, f"Missing tier: {tid}"


@pytest.mark.unit
def test_tier_order_is_complete():
    """TIER_ORDER must contain exactly the four expected tiers."""
    assert set(TIER_ORDER) == set(TIERS.keys())
    assert len(TIER_ORDER) == 4


@pytest.mark.unit
def test_default_tier_is_free():
    assert DEFAULT_TIER == "free"


@pytest.mark.unit
def test_get_tier_returns_correct_dict():
    t = get_tier("starter")
    assert t["id"] == "starter"
    assert t["price_monthly"] == 9


@pytest.mark.unit
def test_get_tier_fallback_for_unknown():
    """Unknown tier ID should fall back to free."""
    t = get_tier("nonexistent_tier")
    assert t["id"] == "free"


@pytest.mark.unit
def test_get_all_tiers_returns_four():
    tiers = get_all_tiers()
    assert len(tiers) == 4


@pytest.mark.unit
def test_all_tiers_have_required_fields():
    required = [
        "id", "name", "tagline", "price_monthly", "price_yearly",
        "lifetime_file_limit", "daily_upload_limit", "monthly_upload_limit",
        "max_storage_destinations", "max_ocr_pages_monthly", "max_file_size_mb",
        "features", "cta",
    ]
    for tid, tier in TIERS.items():
        for field in required:
            assert field in tier, f"Tier '{tid}' missing field '{field}'"


@pytest.mark.unit
def test_free_tier_has_lifetime_limit():
    """Free tier must have a non-zero lifetime file limit."""
    assert TIERS["free"]["lifetime_file_limit"] > 0


@pytest.mark.unit
def test_business_tier_is_unlimited():
    """Business tier must have 0 (unlimited) for all limits."""
    t = TIERS["business"]
    assert t["lifetime_file_limit"] == 0
    assert t["daily_upload_limit"] == 0
    assert t["monthly_upload_limit"] == 0
    assert t["max_storage_destinations"] == 0
    assert t["max_ocr_pages_monthly"] == 0


@pytest.mark.unit
def test_pricing_order():
    """Paid tier prices must increase in order: starter < professional < business."""
    assert TIERS["starter"]["price_monthly"] < TIERS["professional"]["price_monthly"]
    assert TIERS["professional"]["price_monthly"] < TIERS["business"]["price_monthly"]


# ---------------------------------------------------------------------------
# get_user_tier_id tests (mocked DB)
# ---------------------------------------------------------------------------


@pytest.mark.unit
def test_get_user_tier_id_returns_default_when_no_owner():
    db = MagicMock()
    assert get_user_tier_id(db, None) == DEFAULT_TIER


@pytest.mark.unit
def test_get_user_tier_id_returns_profile_tier():
    db = MagicMock()
    profile = MagicMock()
    profile.subscription_tier = "professional"
    db.query.return_value.filter.return_value.first.return_value = profile
    assert get_user_tier_id(db, "user@example.com") == "professional"


@pytest.mark.unit
def test_get_user_tier_id_falls_back_to_free_when_no_profile():
    db = MagicMock()
    db.query.return_value.filter.return_value.first.return_value = None
    assert get_user_tier_id(db, "unknown@example.com") == "free"


@pytest.mark.unit
def test_get_user_tier_id_falls_back_when_tier_is_none():
    db = MagicMock()
    profile = MagicMock()
    profile.subscription_tier = None
    db.query.return_value.filter.return_value.first.return_value = profile
    assert get_user_tier_id(db, "user@example.com") == "free"


# ---------------------------------------------------------------------------
# check_upload_allowed tests (mocked DB)
# ---------------------------------------------------------------------------


@pytest.mark.unit
def test_check_upload_skipped_without_owner():
    """check_upload_allowed should not raise when owner_id is None."""
    db = MagicMock()
    check_upload_allowed(db, None, "free")  # must not raise


@pytest.mark.unit
def test_check_upload_skipped_without_tier():
    """check_upload_allowed should not raise when tier_id is None."""
    db = MagicMock()
    check_upload_allowed(db, "user@example.com", None)  # must not raise


@pytest.mark.unit
def test_check_upload_raises_when_lifetime_exceeded():
    """Free tier: should raise QuotaExceeded when lifetime limit is hit."""
    db = MagicMock()

    with patch("app.utils.subscription.get_lifetime_file_count", return_value=25):
        with pytest.raises(QuotaExceeded) as exc_info:
            check_upload_allowed(db, "user@example.com", "free")

    assert exc_info.value.limit_type == "lifetime"
    assert exc_info.value.limit_value == 25
    assert exc_info.value.current_value == 25


@pytest.mark.unit
def test_check_upload_passes_below_lifetime_limit():
    db = MagicMock()
    with patch("app.utils.subscription.get_lifetime_file_count", return_value=10):
        check_upload_allowed(db, "user@example.com", "free")  # must not raise


@pytest.mark.unit
def test_check_upload_raises_when_daily_exceeded():
    """Starter tier: should raise QuotaExceeded when daily limit is hit."""
    db = MagicMock()

    with patch("app.utils.subscription.get_lifetime_file_count", return_value=0), \
         patch("app.utils.subscription.get_today_file_count", return_value=10):
        with pytest.raises(QuotaExceeded) as exc_info:
            check_upload_allowed(db, "user@example.com", "starter")

    assert exc_info.value.limit_type == "daily"


@pytest.mark.unit
def test_check_upload_raises_when_monthly_exceeded():
    """Starter tier: should raise QuotaExceeded when monthly limit is hit."""
    db = MagicMock()

    with patch("app.utils.subscription.get_lifetime_file_count", return_value=0), \
         patch("app.utils.subscription.get_today_file_count", return_value=0), \
         patch("app.utils.subscription.get_month_file_count", return_value=100):
        with pytest.raises(QuotaExceeded) as exc_info:
            check_upload_allowed(db, "user@example.com", "starter")

    assert exc_info.value.limit_type == "monthly"


@pytest.mark.unit
def test_check_upload_business_tier_never_raises():
    """Business tier has no limits — check_upload_allowed must never raise."""
    db = MagicMock()
    # Even with absurdly high counts, business tier is unlimited
    with patch("app.utils.subscription.get_lifetime_file_count", return_value=999999), \
         patch("app.utils.subscription.get_today_file_count", return_value=999999), \
         patch("app.utils.subscription.get_month_file_count", return_value=999999):
        check_upload_allowed(db, "user@example.com", "business")  # must not raise


# ---------------------------------------------------------------------------
# get_user_usage (mocked DB)
# ---------------------------------------------------------------------------


@pytest.mark.unit
def test_get_user_usage_returns_dict_with_correct_keys():
    db = MagicMock()
    with patch("app.utils.subscription.get_lifetime_file_count", return_value=10), \
         patch("app.utils.subscription.get_today_file_count", return_value=2), \
         patch("app.utils.subscription.get_month_file_count", return_value=8):
        result = get_user_usage(db, "user@example.com")

    assert result == {"lifetime": 10, "today": 2, "month": 8}


# ---------------------------------------------------------------------------
# API: /api/subscriptions/tiers (integration-style, mocked app)
# ---------------------------------------------------------------------------


@pytest.mark.unit
def test_list_tiers_api(client):
    """GET /api/subscriptions/tiers must return all four tiers."""
    resp = client.get("/api/subscriptions/tiers")
    assert resp.status_code == 200
    data = resp.json()
    assert "tiers" in data
    assert len(data["tiers"]) == 4
    ids = [t["id"] for t in data["tiers"]]
    assert "free" in ids
    assert "starter" in ids
    assert "professional" in ids
    assert "business" in ids