import base64
import unittest
from time import time
from typing import Mapping
from urllib.parse import parse_qs, urlparse

import httpx
import jwt
from cryptography.hazmat.primitives.asymmetric import rsa
from pwo import async_test
from kaya.core import HttpContext, KayaApp
from kaya.session import InMemorySessionStore, SessionMixin

from kaya.oidc import OIDCConfig, OIDCMixin
from kaya.oidc._client import OIDCClient


class MockOIDCProvider:
    def __init__(self) -> None:
        self.private_key = rsa.generate_private_key(public_exponent=65537, key_size=2048)
        self.public_key = self.private_key.public_key()
        self.kid = 'mock-key'
        self.issuer = 'https://mock-oidc.local'
        self.nonce = 'nonce-value'
        self.discovery = {
            'issuer': self.issuer,
            'authorization_endpoint': f'{self.issuer}/auth',
            'token_endpoint': f'{self.issuer}/token',
            'userinfo_endpoint': f'{self.issuer}/userinfo',
            'end_session_endpoint': f'{self.issuer}/logout',
            'jwks_uri': f'{self.issuer}/jwks',
        }

    def _public_key_to_jwk(self) -> dict[str, str]:
        numbers = self.public_key.public_numbers()
        e_bytes = numbers.e.to_bytes((numbers.e.bit_length() + 7) // 8, 'big')
        n_bytes = numbers.n.to_bytes((numbers.n.bit_length() + 7) // 8, 'big')
        return {
            'kty': 'RSA',
            'kid': self.kid,
            'use': 'sig',
            'n': base64.urlsafe_b64encode(n_bytes).rstrip(b'=').decode(),
            'e': base64.urlsafe_b64encode(e_bytes).rstrip(b'=').decode(),
            'alg': 'RS256',
        }

    def issue_id_token(self, nonce: str, audience: str, expired: bool = False, wrong_nonce: bool = False) -> str:
        now = time()
        exp = now - 3600 if expired else now + 3600
        payload = {
            'sub': 'user123',
            'iss': self.issuer,
            'aud': audience,
            'iat': now,
            'exp': exp,
            'nonce': 'wrong-nonce' if wrong_nonce else nonce,
        }
        return jwt.encode(
            payload,
            self.private_key,
            algorithm='RS256',
            headers={'kid': self.kid},
        )

    def handle_request(self, request: httpx.Request) -> httpx.Response:
        url = str(request.url)
        path = urlparse(url).path
        # Serve discovery and JWKS for any host so that issuer-mismatch tests can still fetch keys.
        if path == '/.well-known/openid-configuration':
            return httpx.Response(200, json=self.discovery)
        if path == '/jwks':
            return httpx.Response(200, json={'keys': [self._public_key_to_jwk()]})
        if path == '/token' and request.method == 'POST':
            body = request.content.decode()
            data = dict(part.split('=') for part in body.split('&')) if body else {}
            if data.get('grant_type') == 'refresh_token':
                return httpx.Response(200, json={
                    'access_token': 'new-access-token',
                    'refresh_token': 'new-refresh-token',
                    'id_token': self.issue_id_token('refreshed-nonce', data.get('client_id', 'client')),
                    'token_type': 'Bearer',
                })
            return httpx.Response(200, json={
                'access_token': 'mock-access-token',
                'refresh_token': 'mock-refresh-token',
                'id_token': self.issue_id_token(self.nonce, data.get('client_id', 'client')),
                'token_type': 'Bearer',
            })
        if path == '/userinfo':
            return httpx.Response(200, json={'sub': 'user123', 'email': 'user@example.com'})
        if path == '/logout':
            return httpx.Response(200)
        return httpx.Response(404)


class MockTransport(httpx.AsyncBaseTransport):
    def __init__(self, provider: MockOIDCProvider) -> None:
        self._provider = provider

    async def handle_async_request(self, request: httpx.Request) -> httpx.Response:
        return self._provider.handle_request(request)


class OIDCClientTest(unittest.TestCase):

    def setUp(self) -> None:
        self.provider = MockOIDCProvider()
        self.http_client = httpx.AsyncClient(transport=MockTransport(self.provider))
        self.config = OIDCConfig(
            issuer=self.provider.issuer,
            client_id='client',
            client_secret='secret',
            redirect_uri='http://localhost:8000/auth/callback',
            http_client=self.http_client,
        )
        self.client = OIDCClient(self.config)

    @async_test
    async def test_build_authorization_url(self) -> None:
        url, state, nonce, verifier = await self.client.build_authorization_url()
        self.assertIn(self.provider.discovery['authorization_endpoint'], url)
        parsed = urlparse(url)
        query = parse_qs(parsed.query)
        self.assertEqual(['client'], query['client_id'])
        self.assertEqual(['code'], query['response_type'])
        self.assertEqual(['S256'], query['code_challenge_method'])
        self.assertIn('openid', query['scope'][0])
        self.assertEqual([state], query['state'])
        self.assertEqual([nonce], query['nonce'])
        self.assertTrue(len(verifier) > 0)

    @async_test
    async def test_validate_id_token_success(self) -> None:
        token = self.provider.issue_id_token('nonce-value', 'client')
        claims = await self.client.validate_id_token(token, 'nonce-value')
        self.assertEqual('user123', claims['sub'])
        self.assertEqual('nonce-value', claims['nonce'])

    @async_test
    async def test_validate_id_token_wrong_nonce(self) -> None:
        token = self.provider.issue_id_token('nonce-value', 'client', wrong_nonce=True)
        with self.assertRaises(ValueError) as ctx:
            await self.client.validate_id_token(token, 'nonce-value')
        self.assertIn('nonce', str(ctx.exception))

    @async_test
    async def test_validate_id_token_expired(self) -> None:
        token = self.provider.issue_id_token('nonce-value', 'client', expired=True)
        with self.assertRaises(jwt.ExpiredSignatureError):
            await self.client.validate_id_token(token, 'nonce-value')

    @async_test
    async def test_validate_id_token_wrong_issuer(self) -> None:
        token = self.provider.issue_id_token('nonce-value', 'client')
        config = OIDCConfig(
            issuer='https://wrong-issuer.local',
            client_id='client',
            redirect_uri='http://localhost:8000/auth/callback',
            http_client=self.http_client,
        )
        client = OIDCClient(config)
        with self.assertRaises(jwt.InvalidIssuerError):
            await client.validate_id_token(token, 'nonce-value')

    @async_test
    async def test_validate_id_token_disallowed_algorithm(self) -> None:
        token = self.provider.issue_id_token('nonce-value', 'client')
        config = OIDCConfig(
            issuer=self.provider.issuer,
            client_id='client',
            redirect_uri='http://localhost:8000/auth/callback',
            http_client=self.http_client,
            allowed_id_token_algorithms=('ES256',),
        )
        client = OIDCClient(config)
        with self.assertRaises(ValueError) as ctx:
            await client.validate_id_token(token, 'nonce-value')
        self.assertIn('RS256', str(ctx.exception))

    @async_test
    async def test_fetch_userinfo(self) -> None:
        userinfo = await self.client.fetch_userinfo('access-token')
        self.assertEqual('user123', userinfo['sub'])
        self.assertEqual('user@example.com', userinfo['email'])

    @async_test
    async def test_build_logout_url(self) -> None:
        url = await self.client.build_logout_url('id-token')
        self.assertIsNotNone(url)
        assert url is not None
        self.assertIn(self.provider.discovery['end_session_endpoint'], url)
        parsed = urlparse(url)
        query = parse_qs(parsed.query)
        self.assertEqual(['id-token'], query['id_token_hint'])
        self.assertEqual(['/'], query['post_logout_redirect_uri'])


class OIDCMixinTest(unittest.TestCase):

    def _build_app(self, fetch_userinfo: bool = False) -> tuple[KayaApp, OIDCMixin, MockOIDCProvider, InMemorySessionStore]:
        provider = MockOIDCProvider()
        http_client = httpx.AsyncClient(transport=MockTransport(provider))
        store = InMemorySessionStore()
        session = SessionMixin(store)
        config = OIDCConfig(
            issuer=provider.issuer,
            client_id='client',
            client_secret='secret',
            redirect_uri='http://localhost:8000/auth/callback',
            http_client=http_client,
            fetch_userinfo=fetch_userinfo,
        )
        oidc = OIDCMixin(config, session=session)
        app = KayaApp(mixins=[session, oidc])
        return app, oidc, provider, store

    def _setup_routes(self, app: KayaApp, oidc: OIDCMixin) -> None:
        @app.GET('/')
        async def home(ctx: HttpContext) -> None:
            await ctx.send_str(200, 'home')

        @app.GET('/profile')
        @oidc.require_auth
        async def profile(ctx: HttpContext) -> None:
            user = oidc.get_user(ctx)
            if user is None:
                await ctx.send_empty(401)
                return
            await ctx.send_str(200, f'Hello {user.email}')

        @app.GET('/refresh')
        @oidc.require_auth
        async def refresh(ctx: HttpContext) -> None:
            new_token = await oidc.refresh_access_token(ctx.session)
            await ctx.send_str(200, new_token or 'no-token')

    @async_test
    async def test_login_redirect(self) -> None:
        app, oidc, provider, store = self._build_app()
        self._setup_routes(app, oidc)
        transport = httpx.ASGITransport(app=app)
        async with httpx.AsyncClient(transport=transport, base_url='http://127.0.0.1:80') as client:
            r = await client.get('/auth/login', follow_redirects=False)
            self.assertEqual(302, r.status_code)
            location = r.headers['Location']
            self.assertIn(provider.discovery['authorization_endpoint'], location)
            self.assertIn('Set-Cookie', r.headers)

    @async_test
    async def test_callback_success(self) -> None:
        app, oidc, provider, store = self._build_app(fetch_userinfo=True)
        self._setup_routes(app, oidc)
        transport = httpx.ASGITransport(app=app)
        async with httpx.AsyncClient(transport=transport, base_url='http://127.0.0.1:80') as client:
            r = await client.get('/auth/login', follow_redirects=False)
            self.assertEqual(302, r.status_code)
            parsed = urlparse(r.headers['Location'])
            query = parse_qs(parsed.query)
            state = query['state'][0]

            nonce = query['nonce'][0]
            provider.nonce = nonce

            r = await client.get('/auth/callback', params={'code': 'mock-code', 'state': state}, follow_redirects=False)
            self.assertEqual(302, r.status_code)
            self.assertEqual('/', r.headers['Location'])
            self.assertIn('Set-Cookie', r.headers)

            r = await client.get('/profile')
            self.assertEqual(200, r.status_code)
            self.assertIn('user@example.com', r.text)

    @async_test
    async def test_callback_invalid_state(self) -> None:
        app, oidc, provider, store = self._build_app()
        self._setup_routes(app, oidc)
        transport = httpx.ASGITransport(app=app)
        async with httpx.AsyncClient(transport=transport, base_url='http://127.0.0.1:80') as client:
            r = await client.get('/auth/callback', params={'code': 'mock-code', 'state': 'wrong'}, follow_redirects=False)
            self.assertEqual(400, r.status_code)

    @async_test
    async def test_logout(self) -> None:
        app, oidc, provider, store = self._build_app()
        self._setup_routes(app, oidc)
        transport = httpx.ASGITransport(app=app)
        async with httpx.AsyncClient(transport=transport, base_url='http://127.0.0.1:80') as client:
            r = await client.get('/auth/login', follow_redirects=False)
            parsed = urlparse(r.headers['Location'])
            query = parse_qs(parsed.query)
            state = query['state'][0]
            provider.nonce = query['nonce'][0]
            await client.get('/auth/callback', params={'code': 'mock-code', 'state': state}, follow_redirects=False)

            session_id = client.cookies['session_id']
            self.assertIn(session_id, store._data)

            r = await client.get('/auth/logout', follow_redirects=False)
            self.assertEqual(302, r.status_code)
            self.assertIn(provider.discovery['end_session_endpoint'], r.headers['Location'])
            self.assertNotIn(session_id, store._data)

    @async_test
    async def test_require_auth_redirect(self) -> None:
        app, oidc, provider, store = self._build_app()
        self._setup_routes(app, oidc)
        transport = httpx.ASGITransport(app=app)
        async with httpx.AsyncClient(transport=transport, base_url='http://127.0.0.1:80') as client:
            r = await client.get('/profile', follow_redirects=False)
            self.assertEqual(302, r.status_code)
            self.assertEqual('/auth/login', r.headers['Location'])

    @async_test
    async def test_refresh_access_token(self) -> None:
        app, oidc, provider, store = self._build_app()
        self._setup_routes(app, oidc)
        transport = httpx.ASGITransport(app=app)
        async with httpx.AsyncClient(transport=transport, base_url='http://127.0.0.1:80') as client:
            r = await client.get('/auth/login', follow_redirects=False)
            parsed = urlparse(r.headers['Location'])
            query = parse_qs(parsed.query)
            state = query['state'][0]
            provider.nonce = query['nonce'][0]
            await client.get('/auth/callback', params={'code': 'mock-code', 'state': state}, follow_redirects=False)

            r = await client.get('/refresh')
            self.assertEqual(200, r.status_code)
            self.assertEqual('new-access-token', r.text)

    @async_test
    async def test_dependency_applied_automatically(self) -> None:
        # Only pass oidc to KayaApp; SessionMixin should be applied via dependencies.
        provider = MockOIDCProvider()
        http_client = httpx.AsyncClient(transport=MockTransport(provider))
        store = InMemorySessionStore()
        session = SessionMixin(store)
        config = OIDCConfig(
            issuer=provider.issuer,
            client_id='client',
            client_secret='secret',
            redirect_uri='http://localhost:8000/auth/callback',
            http_client=http_client,
        )
        oidc = OIDCMixin(config, session=session)
        app = KayaApp(mixins=[oidc])

        @app.GET('/')
        async def home(ctx: HttpContext) -> None:
            ctx.session['x'] = 1
            await ctx.send_str(200, 'ok')

        transport = httpx.ASGITransport(app=app)
        async with httpx.AsyncClient(transport=transport, base_url='http://127.0.0.1:80') as client:
            r = await client.get('/')
            self.assertEqual(200, r.status_code)
            self.assertIn('Set-Cookie', r.headers)


if __name__ == '__main__':
    unittest.main()