import pytest
import uuid
from datetime import datetime, timedelta
from app.models import User, AuditLog, AuditAlert, AuditAction, SensitivityLevel
from app.services.audit_service import AuditService


@pytest.fixture
def admin_user(db):
    """Create a test admin user."""
    user = User(
        id=str(uuid.uuid4()),
        email="testadmin@example.com",
        name="Test Admin",
        role_id="00000000-0000-0000-0000-000000000001",
        is_active=True,
        is_system_admin=True,
    )
    db.add(user)
    db.commit()
    return user


class TestAuditService:
    """Tests for AuditService."""

    def test_calculate_checksum(self):
        """Test checksum calculation."""
        now = datetime.utcnow()
        checksum1 = AuditService.calculate_checksum(
            "task.create", "resource-1", "user-1", None, now
        )
        checksum2 = AuditService.calculate_checksum(
            "task.create", "resource-1", "user-1", None, now
        )
        # Same inputs should produce same checksum
        assert checksum1 == checksum2
        assert len(checksum1) == 64  # SHA-256 hex length

    def test_checksum_different_for_different_inputs(self):
        """Test that different inputs produce different checksums."""
        now = datetime.utcnow()
        checksum1 = AuditService.calculate_checksum(
            "task.create", "resource-1", "user-1", None, now
        )
        checksum2 = AuditService.calculate_checksum(
            "task.update", "resource-1", "user-1", None, now
        )
        assert checksum1 != checksum2

    def test_detect_changes(self):
        """Test change detection between old and new values."""
        old_values = {"title": "Old Title", "priority": "high"}
        new_values = {"title": "New Title", "priority": "high"}

        changes = AuditService.detect_changes(old_values, new_values)

        assert len(changes) == 1
        assert changes[0]["field"] == "title"
        assert changes[0]["old_value"] == "Old Title"
        assert changes[0]["new_value"] == "New Title"

    def test_detect_no_changes(self):
        """Test that no changes are detected when values are the same."""
        values = {"title": "Same Title", "priority": "high"}
        changes = AuditService.detect_changes(values, values.copy())
        assert len(changes) == 0

    def test_get_sensitivity_level(self):
        """Test sensitivity level mapping."""
        assert AuditService.get_sensitivity_level("task.create") == SensitivityLevel.LOW
        assert AuditService.get_sensitivity_level("task.delete") == SensitivityLevel.MEDIUM
        assert AuditService.get_sensitivity_level("project.delete") == SensitivityLevel.HIGH
        assert AuditService.get_sensitivity_level("user.permission_change") == SensitivityLevel.CRITICAL
        assert AuditService.get_sensitivity_level("unknown.event") == SensitivityLevel.LOW

    def test_log_event(self, db, admin_user):
        """Test logging an audit event."""
        log = AuditService.log_event(
            db=db,
            event_type="task.create",
            resource_type="task",
            action=AuditAction.CREATE,
            user_id=admin_user.id,
            resource_id=str(uuid.uuid4()),
            changes=[{"field": "title", "old_value": None, "new_value": "Test Task"}],
        )

        db.commit()

        assert log.id is not None
        assert log.event_type == "task.create"
        assert log.action == "create"
        assert log.sensitivity_level == "low"
        assert log.checksum is not None

    def test_verify_checksum_valid(self, db, admin_user):
        """Test verifying a valid checksum."""
        log = AuditService.log_event(
            db=db,
            event_type="task.create",
            resource_type="task",
            action=AuditAction.CREATE,
            user_id=admin_user.id,
            resource_id=str(uuid.uuid4()),
        )

        db.commit()
        db.refresh(log)

        assert AuditService.verify_checksum(log) is True

    def test_verify_checksum_invalid(self, db, admin_user):
        """Test that tampered checksums are detected."""
        log = AuditService.log_event(
            db=db,
            event_type="task.create",
            resource_type="task",
            action=AuditAction.CREATE,
            user_id=admin_user.id,
            resource_id=str(uuid.uuid4()),
        )

        db.commit()
        db.refresh(log)

        # Tamper with the checksum
        log.checksum = "0" * 64
        assert AuditService.verify_checksum(log) is False


@pytest.fixture
def regular_user(db):
    """Create a non-admin user."""
    user = User(
        id=str(uuid.uuid4()),
        email="regular@example.com",
        name="Regular User",
        role_id="00000000-0000-0000-0000-000000000003",
        is_active=True,
        is_system_admin=False,
    )
    db.add(user)
    db.commit()
    return user


@pytest.fixture
def regular_user_token(client, mock_redis, regular_user):
    """Get a token for regular user."""
    from app.core.security import create_access_token, create_token_payload

    token_data = create_token_payload(
        user_id=regular_user.id,
        email=regular_user.email,
        role="engineer",
        department_id=None,
        is_system_admin=False,
    )
    token = create_access_token(token_data)
    mock_redis.setex(f"session:{regular_user.id}", 900, token)
    return token


class TestAuditAPI:
    """Tests for Audit API endpoints."""

    def test_list_audit_logs_requires_admin(self, client, regular_user_token):
        """Test that non-admin users cannot access audit logs."""
        response = client.get(
            "/api/audit-logs",
            headers={"Authorization": f"Bearer {regular_user_token}"},
        )
        assert response.status_code == 403
        assert "Admin access required" in response.json()["detail"]

    def test_list_audit_logs(self, client, admin_token, db):
        """Test listing audit logs as admin."""
        # Create some audit logs
        for i in range(3):
            log = AuditLog(
                id=str(uuid.uuid4()),
                event_type="task.create",
                resource_type="task",
                resource_id=str(uuid.uuid4()),
                user_id="00000000-0000-0000-0000-000000000001",
                action="create",
                sensitivity_level="low",
                checksum="0" * 64,
            )
            db.add(log)
        db.commit()

        response = client.get(
            "/api/audit-logs",
            headers={"Authorization": f"Bearer {admin_token}"},
        )
        assert response.status_code == 200
        data = response.json()
        assert data["total"] >= 3
        assert len(data["logs"]) >= 3

    def test_list_audit_logs_with_filters(self, client, admin_token, db):
        """Test filtering audit logs."""
        # Create logs with different resource types
        for resource_type in ["task", "project", "task"]:
            log = AuditLog(
                id=str(uuid.uuid4()),
                event_type=f"{resource_type}.create",
                resource_type=resource_type,
                resource_id=str(uuid.uuid4()),
                user_id="00000000-0000-0000-0000-000000000001",
                action="create",
                sensitivity_level="low",
                checksum="0" * 64,
            )
            db.add(log)
        db.commit()

        response = client.get(
            "/api/audit-logs?resource_type=project",
            headers={"Authorization": f"Bearer {admin_token}"},
        )
        assert response.status_code == 200
        data = response.json()
        assert all(log["resource_type"] == "project" for log in data["logs"])

    def test_get_resource_history(self, client, admin_token, db):
        """Test getting resource history."""
        resource_id = str(uuid.uuid4())

        # Create multiple logs for the same resource
        for event in ["task.create", "task.update", "task.update"]:
            log = AuditLog(
                id=str(uuid.uuid4()),
                event_type=event,
                resource_type="task",
                resource_id=resource_id,
                user_id="00000000-0000-0000-0000-000000000001",
                action="create" if "create" in event else "update",
                sensitivity_level="low",
                checksum="0" * 64,
            )
            db.add(log)
        db.commit()

        response = client.get(
            f"/api/audit-logs/resource/task/{resource_id}",
            headers={"Authorization": f"Bearer {admin_token}"},
        )
        assert response.status_code == 200
        data = response.json()
        assert data["total"] == 3
        assert all(log["resource_id"] == resource_id for log in data["logs"])

    def test_verify_integrity(self, client, admin_token, db):
        """Test integrity verification."""
        now = datetime.utcnow()

        # Create a valid log
        log = AuditService.log_event(
            db=db,
            event_type="task.create",
            resource_type="task",
            action=AuditAction.CREATE,
            user_id="00000000-0000-0000-0000-000000000001",
            resource_id=str(uuid.uuid4()),
        )
        db.commit()

        response = client.post(
            "/api/audit-logs/verify-integrity",
            headers={"Authorization": f"Bearer {admin_token}"},
            json={
                "start_date": (now - timedelta(hours=1)).isoformat(),
                "end_date": (now + timedelta(hours=1)).isoformat(),
            },
        )
        assert response.status_code == 200
        data = response.json()
        assert data["total_checked"] >= 1
        assert data["invalid_count"] == 0

    def test_acknowledge_alert(self, client, admin_token, db):
        """Test acknowledging an alert."""
        # Create a log and alert
        log = AuditLog(
            id=str(uuid.uuid4()),
            event_type="project.delete",
            resource_type="project",
            resource_id=str(uuid.uuid4()),
            user_id="00000000-0000-0000-0000-000000000001",
            action="delete",
            sensitivity_level="high",
            checksum="0" * 64,
        )
        db.add(log)
        db.flush()

        alert = AuditAlert(
            id=str(uuid.uuid4()),
            audit_log_id=log.id,
            alert_type="project.delete",
            recipients=["00000000-0000-0000-0000-000000000001"],
            message="Test alert",
        )
        db.add(alert)
        db.commit()

        response = client.put(
            f"/api/audit-alerts/{alert.id}/acknowledge",
            headers={"Authorization": f"Bearer {admin_token}"},
        )
        assert response.status_code == 200
        data = response.json()
        assert data["is_acknowledged"] is True
        assert data["acknowledged_by"] is not None

    def test_export_csv(self, client, admin_token, db):
        """Test CSV export."""
        # Create some logs
        for i in range(3):
            log = AuditLog(
                id=str(uuid.uuid4()),
                event_type="task.create",
                resource_type="task",
                resource_id=str(uuid.uuid4()),
                user_id="00000000-0000-0000-0000-000000000001",
                action="create",
                sensitivity_level="low",
                checksum="0" * 64,
            )
            db.add(log)
        db.commit()

        response = client.get(
            "/api/audit-logs/export",
            headers={"Authorization": f"Bearer {admin_token}"},
        )
        assert response.status_code == 200
        assert "text/csv" in response.headers["content-type"]
        assert "attachment" in response.headers.get("content-disposition", "")