"""Tests for ``pallas.image_passthrough``.

Drives the ``after_tool_call`` hook with handcrafted
``PromptMessageExtended`` objects and asserts the collection, cap, and
result-assembly behaviour. No fast-agent runtime is involved — the hook is
a pure async function. Uses ``asyncio.run`` directly to match the
convention in the other test modules (pallas has no pytest-asyncio
dependency).
"""
from __future__ import annotations

import asyncio
from types import SimpleNamespace

from fast_agent.types import PromptMessageExtended
from fastmcp.tools import ToolResult
from mcp.types import CallToolResult, ImageContent, TextContent

from pallas.image_passthrough import (
    ImageCollector,
    build_result,
    install_for_request,
)


def _run(coro):
    return asyncio.run(coro)


def _image(tag: str) -> ImageContent:
    return ImageContent(type="image", data=f"b64-{tag}", mimeType="image/png")


def _result_message(*blocks, call_id: str = "toolu_1") -> PromptMessageExtended:
    return PromptMessageExtended(
        role="user",
        content=[],
        tool_results={call_id: CallToolResult(content=list(blocks))},
    )


def _collector(max_images: int = 8) -> ImageCollector:
    return ImageCollector(
        agent_name="dolores", conversation_id="c1", max_images=max_images
    )


def test_collects_images_and_ignores_text():
    collector = _collector()
    hook = collector.as_after_tool_call_hook()

    async def go():
        await hook(None, _result_message(TextContent(type="text", text="snapshot")))
        await hook(None, _result_message(_image("a")))
        await hook(
            None,
            _result_message(TextContent(type="text", text="took it"), _image("b")),
        )

    _run(go())
    assert [i.data for i in collector.collected()] == ["b64-a", "b64-b"]


def test_collects_across_multiple_results_in_one_message():
    collector = _collector()
    hook = collector.as_after_tool_call_hook()
    message = PromptMessageExtended(
        role="user",
        content=[],
        tool_results={
            "toolu_1": CallToolResult(content=[_image("a")]),
            "toolu_2": CallToolResult(content=[_image("b")]),
        },
    )

    _run(hook(None, message))
    assert len(collector.collected()) == 2


def test_cap_keeps_most_recent():
    collector = _collector(max_images=2)
    hook = collector.as_after_tool_call_hook()

    async def go():
        for tag in ("a", "b", "c", "d"):
            await hook(None, _result_message(_image(tag)))

    _run(go())
    assert [i.data for i in collector.collected()] == ["b64-c", "b64-d"]


def test_empty_tool_results_are_harmless():
    collector = _collector()
    hook = collector.as_after_tool_call_hook()
    message = PromptMessageExtended(role="user", content=[], tool_results=None)

    _run(hook(None, message))
    assert collector.collected() == []


def test_build_result_plain_text_when_no_images():
    assert build_result("answer", []) == "answer"


def test_build_result_wraps_text_and_images():
    result = build_result("answer", [_image("a"), _image("b")])
    assert isinstance(result, ToolResult)
    assert [b.type for b in result.content] == ["text", "image", "image"]
    assert result.content[0].text == "answer"
    assert result.content[1].data == "b64-a"


def test_build_result_omits_empty_text_block():
    result = build_result("", [_image("a")])
    assert isinstance(result, ToolResult)
    assert [b.type for b in result.content] == ["image"]


def test_install_disabled_with_nonpositive_max():
    agent = SimpleNamespace(tool_runner_hooks="sentinel")
    collector, restore = install_for_request(
        agent, agent_name="a", conversation_id=None, max_images=0
    )
    assert collector is None
    assert agent.tool_runner_hooks == "sentinel"  # untouched
    restore()  # no-op, must not raise


def test_install_merges_and_restores():
    agent = SimpleNamespace(tool_runner_hooks=None)
    collector, restore = install_for_request(
        agent, agent_name="a", conversation_id=None
    )
    assert collector is not None
    assert agent.tool_runner_hooks is not None
    assert agent.tool_runner_hooks.after_tool_call is not None
    restore()
    assert agent.tool_runner_hooks is None