# Copyright 2025 Google LLC.
# Copyright (c) Microsoft Corporation.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
from json import JSONDecoder

import pytest
import pytest_asyncio
from test_helpers import execute_command, goto_url

USER_AGENT_HEADER_NAME = "User-Agent"
SOME_USER_AGENT = "some user agent"
ANOTHER_USER_AGENT = "another user agent"


@pytest_asyncio.fixture
async def default_user_agent(context_id, get_navigator_user_agent):
    """
    Returns default user agent.
    """
    return await get_navigator_user_agent(context_id)


@pytest.fixture
def get_navigator_user_agent(websocket):

    async def get_navigator_user_agent(context_id):
        """
        Returns browsing context's current user agent accessed via navigator.
        """
        resp = await execute_command(
            websocket,
            {
                "method": "script.evaluate",
                "params": {
                    "expression": "window.navigator.userAgent",
                    "target": {"context": context_id},
                    "awaitPromise": True,
                },
            },
        )

        return resp["result"]["value"] if "result" in resp else resp

    return get_navigator_user_agent


@pytest.fixture
def assert_network_user_agent(websocket, get_url_echo):
    """Assert the `User-Agent` header is set during navigation and during fetch."""

    async def assert_network_user_agent(context_id, expected_user_agent, same_origin):
        # First navigate to the echo page.
        await goto_url(websocket, context_id, get_url_echo(same_origin))
        # Get the navigation headers.
        response = await execute_command(
            websocket,
            {
                "method": "script.evaluate",
                "params": {
                    "expression": "window.document.body.textContent",
                    "awaitPromise": True,
                    "target": {"context": context_id},
                },
            },
        )
        response_obj = JSONDecoder().decode(response["result"]["value"])
        headers = response_obj["headers"]
        # Assert the right user agent header was sent on the navigation request.
        assert USER_AGENT_HEADER_NAME in headers
        assert headers[USER_AGENT_HEADER_NAME] == expected_user_agent

        # Make a fetch request.
        response = await execute_command(
            websocket,
            {
                "method": "script.evaluate",
                "params": {
                    "expression": f"fetch('{get_url_echo(same_origin)}').then(r => r.text())",
                    "awaitPromise": True,
                    "target": {"context": context_id},
                },
            },
        )
        response_obj = JSONDecoder().decode(response["result"]["value"])
        headers = response_obj["headers"]
        # Assert the right user agent header was sent on the navigation request.
        assert USER_AGENT_HEADER_NAME in headers
        assert headers[USER_AGENT_HEADER_NAME] == expected_user_agent

    return assert_network_user_agent


@pytest.fixture
def assert_navigator_user_agent(get_navigator_user_agent):
    """Assert the `window.navigator.userAgent` returns the expected value."""

    async def assert_navigator_user_agent(context_id, expected_user_agent):
        assert await get_navigator_user_agent(context_id) == expected_user_agent

    return assert_navigator_user_agent


@pytest.fixture
def assert_user_agent(assert_navigator_user_agent, assert_network_user_agent):
    """Assert the user agent is emulated properly both in DOM and in network."""

    async def assert_user_agent(context_id, expected_user_agent, same_origin=True):
        await assert_navigator_user_agent(context_id, expected_user_agent)
        await assert_network_user_agent(context_id, expected_user_agent, same_origin)

    return assert_user_agent


@pytest.mark.asyncio
async def test_user_agent_global_set_and_clear(
    websocket,
    context_id,
    default_user_agent,
    assert_user_agent,
    user_context_id,
    create_context,
):
    # Set global override.
    await execute_command(
        websocket,
        {
            "method": "emulation.setUserAgentOverride",
            "params": {"userAgent": SOME_USER_AGENT},
        },
    )

    # Assert the override applies to the existing context.
    await assert_user_agent(context_id, SOME_USER_AGENT)

    # Assert the override applies to new browsing contexts.
    browsing_context_id_1 = await create_context()
    await assert_user_agent(browsing_context_id_1, SOME_USER_AGENT)

    browsing_context_id_2 = await create_context(user_context_id)
    await assert_user_agent(browsing_context_id_2, SOME_USER_AGENT)

    await execute_command(
        websocket,
        {"method": "emulation.setUserAgentOverride", "params": {"userAgent": None}},
    )
    await assert_user_agent(context_id, default_user_agent)
    await assert_user_agent(browsing_context_id_1, default_user_agent)
    await assert_user_agent(browsing_context_id_2, default_user_agent)


@pytest.mark.asyncio
async def test_user_agent_per_user_context(
    websocket, user_context_id, create_context, assert_user_agent
):
    # Set different user_agent overrides for different user contexts.
    await execute_command(
        websocket,
        {
            "method": "emulation.setUserAgentOverride",
            "params": {"userContexts": ["default"], "userAgent": SOME_USER_AGENT},
        },
    )
    await execute_command(
        websocket,
        {
            "method": "emulation.setUserAgentOverride",
            "params": {"userContexts": [user_context_id], "userAgent": SOME_USER_AGENT},
        },
    )

    # Assert the overrides applied for the right contexts.
    browsing_context_id_1 = await create_context()
    await assert_user_agent(browsing_context_id_1, SOME_USER_AGENT)

    browsing_context_id_2 = await create_context(user_context_id)
    await assert_user_agent(browsing_context_id_2, SOME_USER_AGENT)


@pytest.mark.asyncio
async def test_user_agent_per_browsing_context(
    websocket, context_id, another_context_id, assert_user_agent
):
    # Set different user_agent overrides for different user contexts.
    await execute_command(
        websocket,
        {
            "method": "emulation.setUserAgentOverride",
            "params": {"contexts": [context_id], "userAgent": SOME_USER_AGENT},
        },
    )
    await execute_command(
        websocket,
        {
            "method": "emulation.setUserAgentOverride",
            "params": {"contexts": [another_context_id], "userAgent": SOME_USER_AGENT},
        },
    )

    await assert_user_agent(context_id, SOME_USER_AGENT)
    await assert_user_agent(another_context_id, SOME_USER_AGENT)


@pytest.mark.asyncio
async def test_user_agent_affects_iframe(
    websocket, context_id, iframe_id, html, default_user_agent, assert_user_agent
):
    await execute_command(
        websocket,
        {
            "method": "emulation.setUserAgentOverride",
            "params": {"contexts": [context_id], "userAgent": SOME_USER_AGENT},
        },
    )

    await assert_user_agent(iframe_id, SOME_USER_AGENT)

    # Move iframe out of process
    await goto_url(websocket, iframe_id, html("<h1>FRAME</h1>", same_origin=False))
    # Assert user_agent emulation persisted.
    await assert_user_agent(iframe_id, SOME_USER_AGENT, same_origin=False)

    await execute_command(
        websocket,
        {
            "method": "emulation.setUserAgentOverride",
            "params": {"contexts": [context_id], "userAgent": SOME_USER_AGENT},
        },
    )
    await assert_user_agent(iframe_id, SOME_USER_AGENT, same_origin=False)

    await execute_command(
        websocket,
        {
            "method": "emulation.setUserAgentOverride",
            "params": {"contexts": [context_id], "userAgent": None},
        },
    )
    await assert_user_agent(iframe_id, default_user_agent, same_origin=False)


@pytest.mark.asyncio
async def test_user_agent_per_iframe(
    websocket, context_id, iframe_id, html, default_user_agent, assert_user_agent
):
    with pytest.raises(
        Exception,
        match=str(
            {
                "error": "invalid argument",
                "message": "The command is only supported on the top-level context",
            }
        ),
    ):
        await execute_command(
            websocket,
            {
                "method": "emulation.setUserAgentOverride",
                "params": {"contexts": [iframe_id], "userAgent": SOME_USER_AGENT},
            },
        )


@pytest.mark.asyncio
async def test_user_agent_invalid_value(websocket, context_id):
    invalid_user_agent = ""
    with pytest.raises(
        Exception,
        match=str(
            {
                "error": "unsupported operation",
                "message": "empty user agent string is not supported",
            }
        ),
    ):
        await execute_command(
            websocket,
            {
                "method": "emulation.setUserAgentOverride",
                "params": {"contexts": [context_id], "userAgent": invalid_user_agent},
            },
        )