import uuid
import base64
import tempfile
from pathlib import Path
from unittest.mock import patch

from cryptography.fernet import Fernet
from django.contrib.auth import get_user_model
from django.test import TestCase, override_settings
from django.urls import path
from rest_framework.response import Response
from rest_framework.test import APIClient

from apps.api.authentication import ApiKeyAuthentication
from apps.api.views import ExternalApiView
from apps.ai.models import AiModel, ModelAlias
from apps.ai.providers import (
    AiCapabilityError,
    AiProviderError,
    ImageGenerationResult,
    TextGenerationResult,
)
from apps.billing.models import CallRecord, PointsLedger, PricingRule
from apps.users.models import ApiKey
from apps.users.models import UserWallet


TEST_ENCRYPTION_KEY = Fernet.generate_key().decode("ascii")


class AuthenticatedEchoView(ExternalApiView):
    def get(self, request):
        return Response(
            {
                "user_id": request.user.id,
                "api_key_id": request.auth.id,
            }
        )


urlpatterns = [
    path("api/test-auth/", AuthenticatedEchoView.as_view()),
]


@override_settings(ROOT_URLCONF=__name__)
class ApiKeyAuthenticationTests(TestCase):
    url = "/api/test-auth/"

    def setUp(self):
        suffix = uuid.uuid4().hex[:8]
        self.user = get_user_model().objects.create_user(
            username=f"api-user-{suffix}",
            email=f"api-user-{suffix}@example.com",
            password="password",
        )
        self.api_key, self.raw_key = ApiKey.create_for_user(self.user, name="test")
        self.client = APIClient()

    def auth_header(self, raw_key: str | None = None) -> dict:
        return {"HTTP_AUTHORIZATION": f"Bearer {raw_key or self.raw_key}"}

    def test_external_api_view_only_uses_api_key_authentication(self):
        self.assertEqual(AuthenticatedEchoView.authentication_classes, (ApiKeyAuthentication,))

    def test_valid_bearer_key_authenticates_user_and_api_key(self):
        response = self.client.get(self.url, **self.auth_header())

        self.assertEqual(response.status_code, 200)
        self.assertEqual(response.data["user_id"], self.user.id)
        self.assertEqual(response.data["api_key_id"], self.api_key.id)

        self.api_key.refresh_from_db()
        self.assertIsNotNone(self.api_key.last_used_at)

    def test_missing_api_key_returns_401(self):
        response = self.client.get(self.url)

        self.assertEqual(response.status_code, 401)
        self.assertEqual(response["WWW-Authenticate"], "Bearer")
        self.assertEqual(response.data["error"]["code"], "unauthorized")

    def test_invalid_api_key_returns_401(self):
        response = self.client.get(self.url, **self.auth_header("sk_cmhub_invalid"))

        self.assertEqual(response.status_code, 401)
        self.assertEqual(response["WWW-Authenticate"], "Bearer")
        self.assertEqual(response.data["error"]["code"], "unauthorized")

    def test_malformed_authorization_header_returns_401(self):
        response = self.client.get(self.url, HTTP_AUTHORIZATION=f"Token {self.raw_key}")

        self.assertEqual(response.status_code, 401)
        self.assertEqual(response.data["error"]["code"], "unauthorized")

    def test_revoked_api_key_returns_403(self):
        self.api_key.status = ApiKey.Status.REVOKED
        self.api_key.save(update_fields=("status", "updated_at"))

        response = self.client.get(self.url, **self.auth_header())

        self.assertEqual(response.status_code, 403)
        self.assertEqual(response.data["error"]["code"], "account_disabled")

    def test_disabled_user_returns_403(self):
        self.user.status = self.user.Status.DISABLED
        self.user.save(update_fields=("status",))

        response = self.client.get(self.url, **self.auth_header())

        self.assertEqual(response.status_code, 403)
        self.assertEqual(response.data["error"]["code"], "account_disabled")

    def test_web_session_login_is_not_accepted_for_external_api(self):
        self.client.force_login(self.user)

        response = self.client.get(self.url)

        self.assertEqual(response.status_code, 401)
        self.assertEqual(response.data["error"]["code"], "unauthorized")


class FakeGenerationProvider:
    def __init__(self, *, capabilities=None):
        self._capabilities = set(capabilities or {"text", "image", "vision"})
        self.text_calls = []
        self.image_calls = []
        self.text_error = None
        self.image_error = None

    def capabilities(self):
        return set(self._capabilities)

    def generate_text(self, prompt, model, **kwargs):
        self.text_calls.append({"prompt": prompt, "model": model, **kwargs})
        if self.text_error is not None:
            raise self.text_error
        return TextGenerationResult(
            text="测试标题一",
            titles=("测试标题一", "测试标题二"),
            model_used=model.model,
            raw={"secret": "SECRET_RAW_SHOULD_NOT_BE_STORED"},
        )

    def generate_image(self, prompt, model, **kwargs):
        self.image_calls.append({"prompt": prompt, "model": model, **kwargs})
        if self.image_error is not None:
            raise self.image_error
        return ImageGenerationResult(
            image=b"generated-image-bytes",
            model_used=model.model,
            raw={"b64_json": "SECRET_RAW_SHOULD_NOT_BE_STORED"},
        )


@override_settings(AI_KEY_ENCRYPTION_KEY=TEST_ENCRYPTION_KEY)
class GenerateApiTests(TestCase):
    def setUp(self):
        suffix = uuid.uuid4().hex[:8]
        self.media_dir = tempfile.TemporaryDirectory()
        self.addCleanup(self.media_dir.cleanup)
        media_override = override_settings(
            MEDIA_ROOT=self.media_dir.name,
            MEDIA_URL="/media/",
        )
        media_override.enable()
        self.addCleanup(media_override.disable)

        self.user = get_user_model().objects.create_user(
            username=f"generate-user-{suffix}",
            email=f"generate-user-{suffix}@example.com",
            password="password",
        )
        self.wallet = UserWallet.objects.create(user=self.user, points_balance=100)
        self.api_key, self.raw_key = ApiKey.create_for_user(self.user, name="generate")
        self.client = APIClient()
        self.provider = FakeGenerationProvider()

        self.title_model = self.create_ai_model(
            name=f"title-model-{suffix}",
            model=f"gpt-title-{suffix}",
            capabilities=["text", "vision"],
        )
        self.image_model = self.create_ai_model(
            name=f"image-model-{suffix}",
            model=f"gpt-image-{suffix}",
            capabilities=["image", "vision"],
        )
        self.title_alias = f"title-standard-{suffix}"
        self.image_alias = f"image-hd-{suffix}"
        ModelAlias.objects.create(
            operation_type=ModelAlias.OperationType.TITLE,
            alias=self.title_alias,
            ai_model=self.title_model,
            is_default=True,
        )
        ModelAlias.objects.create(
            operation_type=ModelAlias.OperationType.IMAGE,
            alias=self.image_alias,
            ai_model=self.image_model,
            is_default=True,
        )
        PricingRule.objects.create(
            operation_type=CallRecord.OperationType.TITLE,
            alias=self.title_alias,
            points_cost=2,
        )
        PricingRule.objects.create(
            operation_type=CallRecord.OperationType.IMAGE,
            alias=self.image_alias,
            resolution="1K",
            points_cost=10,
        )

    def create_ai_model(self, *, name, model, capabilities):
        ai_model = AiModel(
            name=name,
            url="https://api.example.test/v1",
            model=model,
            api_type=AiModel.ApiType.CHAT,
            capabilities=capabilities,
        )
        ai_model.set_api_key("sk-test-secret")
        ai_model.save()
        return ai_model

    def auth_header(self) -> dict:
        return {"HTTP_AUTHORIZATION": f"Bearer {self.raw_key}"}

    def post_with_provider(self, path, payload, provider=None):
        with patch("apps.api.generation.get_provider", return_value=provider or self.provider):
            return self.client.post(path, payload, format="json", **self.auth_header())

    def test_generate_title_uses_default_alias_charges_points_and_writes_call_record(self):
        response = self.post_with_provider(
            "/api/v1/generate/title",
            {
                "prompt": "生成标题",
                "resolution": "1k",
                "parameters": {"temperature": 0.2, "model": "bad-overridden-model"},
            },
        )

        self.assertEqual(response.status_code, 200)
        self.assertEqual(response.data["titles"], ["测试标题一", "测试标题二"])
        self.assertEqual(response.data["alias"], self.title_alias)
        self.assertEqual(response.data["model_used"], self.title_model.model)
        self.assertEqual(response.data["points_cost"], 2)
        self.assertEqual(response.data["points_balance"], 98)
        self.assertEqual(len(self.provider.text_calls), 1)
        self.assertEqual(self.provider.text_calls[0]["model"].model, self.title_model.model)

        self.wallet.refresh_from_db()
        self.assertEqual(self.wallet.points_balance, 98)
        call = CallRecord.objects.get(pk=response.data["call_id"])
        self.assertEqual(call.status, CallRecord.Status.SUCCESS)
        self.assertEqual(call.api_key, self.api_key)
        self.assertEqual(call.alias, self.title_alias)
        self.assertEqual(call.model_used, self.title_model.model)
        self.assertEqual(call.resolution, "1K")
        self.assertNotIn("SECRET_RAW", call.result_summary)
        self.assertEqual(
            PointsLedger.objects.filter(
                user=self.user,
                change_type=PointsLedger.ChangeType.CONSUME,
            ).count(),
            1,
        )

    def test_generate_image_stores_file_returns_url_and_does_not_store_raw_base64(self):
        encoded = base64.b64encode(b"input-image").decode("ascii")

        response = self.post_with_provider(
            "/api/v1/generate/image",
            {
                "prompt": "生成图片",
                "model": self.image_alias,
                "image_base64": f"data:image/png;base64,{encoded}",
                "resolution": "1K",
                "aspect_ratio": "1:1",
            },
        )

        self.assertEqual(response.status_code, 200)
        self.assertEqual(response.data["alias"], self.image_alias)
        self.assertEqual(response.data["model_used"], self.image_model.model)
        self.assertEqual(response.data["points_cost"], 10)
        self.assertEqual(response.data["points_balance"], 90)
        self.assertTrue(response.data["image_url"].startswith("http://testserver/media/"))
        self.assertEqual(self.provider.image_calls[0]["image"], b"input-image")

        media_relative_path = response.data["image_url"].split("/media/", 1)[1]
        self.assertTrue((Path(self.media_dir.name) / media_relative_path).exists())

        call = CallRecord.objects.get(pk=response.data["call_id"])
        self.assertEqual(call.status, CallRecord.Status.SUCCESS)
        self.assertEqual(call.result_ref, response.data["image_url"])
        self.assertEqual(call.result_summary, "image_bytes=21")
        self.assertNotIn("SECRET_RAW", call.result_ref + call.result_summary)

    def test_insufficient_points_returns_402_without_calling_provider_or_writing_call(self):
        self.wallet.points_balance = 1
        self.wallet.save(update_fields=("points_balance", "updated_at"))

        response = self.post_with_provider(
            "/api/v1/generate/title",
            {"prompt": "生成标题", "model": self.title_alias},
        )

        self.assertEqual(response.status_code, 402)
        self.assertEqual(response.data["error"]["code"], "insufficient_points")
        self.assertEqual(self.provider.text_calls, [])
        self.assertFalse(CallRecord.objects.filter(user=self.user).exists())
        self.assertFalse(PointsLedger.objects.filter(user=self.user).exists())
        self.wallet.refresh_from_db()
        self.assertEqual(self.wallet.points_balance, 1)

    def test_missing_pricing_rule_returns_400_without_charging(self):
        PricingRule.objects.filter(alias=self.title_alias).delete()

        response = self.post_with_provider(
            "/api/v1/generate/title",
            {"prompt": "生成标题", "model": self.title_alias},
        )

        self.assertEqual(response.status_code, 400)
        self.assertEqual(response.data["error"]["code"], "no_pricing_rule")
        self.assertEqual(self.provider.text_calls, [])
        self.assertFalse(CallRecord.objects.filter(user=self.user).exists())
        self.wallet.refresh_from_db()
        self.assertEqual(self.wallet.points_balance, 100)

    def test_alias_capability_mismatch_returns_model_not_allowed_without_charging(self):
        bad_alias = f"bad-title-{uuid.uuid4().hex[:8]}"
        ModelAlias.objects.create(
            operation_type=ModelAlias.OperationType.TITLE,
            alias=bad_alias,
            ai_model=self.image_model,
        )
        PricingRule.objects.create(
            operation_type=CallRecord.OperationType.TITLE,
            alias=bad_alias,
            points_cost=2,
        )

        response = self.post_with_provider(
            "/api/v1/generate/title",
            {"prompt": "生成标题", "model": bad_alias},
        )

        self.assertEqual(response.status_code, 400)
        self.assertEqual(response.data["error"]["code"], "model_not_allowed")
        self.assertEqual(self.provider.text_calls, [])
        self.assertFalse(CallRecord.objects.filter(alias=bad_alias).exists())

    def test_provider_capability_mismatch_returns_model_not_allowed_before_charging(self):
        text_only_provider = FakeGenerationProvider(capabilities={"text"})

        response = self.post_with_provider(
            "/api/v1/generate/image",
            {"prompt": "生成图片", "model": self.image_alias, "resolution": "1K"},
            provider=text_only_provider,
        )

        self.assertEqual(response.status_code, 400)
        self.assertEqual(response.data["error"]["code"], "model_not_allowed")
        self.assertEqual(text_only_provider.image_calls, [])
        self.assertFalse(CallRecord.objects.filter(user=self.user).exists())

    def test_upstream_failure_refunds_precharged_points_and_marks_call_failed(self):
        self.provider.text_error = AiProviderError("provider timeout")

        response = self.post_with_provider(
            "/api/v1/generate/title",
            {"prompt": "生成标题", "model": self.title_alias},
        )

        self.assertEqual(response.status_code, 502)
        self.assertEqual(response.data["error"]["code"], "upstream_error")
        self.wallet.refresh_from_db()
        self.assertEqual(self.wallet.points_balance, 100)

        call = CallRecord.objects.get(user=self.user)
        self.assertEqual(call.status, CallRecord.Status.FAILED)
        self.assertIn("provider timeout", call.error_message)
        self.assertEqual(
            PointsLedger.objects.filter(
                ref_call=call,
                change_type=PointsLedger.ChangeType.CONSUME,
            ).count(),
            1,
        )
        self.assertEqual(
            PointsLedger.objects.filter(
                ref_call=call,
                change_type=PointsLedger.ChangeType.REFUND,
            ).count(),
            1,
        )

    def test_provider_capability_error_returns_400_and_refunds_points(self):
        self.provider.image_error = AiCapabilityError("input image is required")

        response = self.post_with_provider(
            "/api/v1/generate/image",
            {"prompt": "生成图片", "model": self.image_alias, "resolution": "1K"},
        )

        self.assertEqual(response.status_code, 400)
        self.assertEqual(response.data["error"]["code"], "bad_request")
        self.wallet.refresh_from_db()
        self.assertEqual(self.wallet.points_balance, 100)
        call = CallRecord.objects.get(user=self.user)
        self.assertEqual(call.status, CallRecord.Status.FAILED)
        self.assertEqual(
            PointsLedger.objects.filter(
                ref_call=call,
                change_type=PointsLedger.ChangeType.REFUND,
            ).count(),
            1,
        )