"""Tests for Discord reply_to_mode functionality.

Covers the threading behavior control for multi-chunk replies:
- "off": Never reply-reference to original message
- "first": Only first chunk uses reply reference (default)
- "all": All chunks reply-reference the original message
"""
import os
import sys
from types import SimpleNamespace
from unittest.mock import MagicMock, AsyncMock, patch

import pytest

from gateway.config import PlatformConfig, GatewayConfig, Platform, _apply_env_overrides


def _ensure_discord_mock():
    """Install a mock discord module when discord.py isn't available."""
    if "discord" in sys.modules and hasattr(sys.modules["discord"], "__file__"):
        return

    discord_mod = MagicMock()
    discord_mod.Intents.default.return_value = MagicMock()
    discord_mod.Client = MagicMock
    discord_mod.File = MagicMock
    discord_mod.DMChannel = type("DMChannel", (), {})
    discord_mod.Thread = type("Thread", (), {})
    discord_mod.ForumChannel = type("ForumChannel", (), {})
    discord_mod.ui = SimpleNamespace(View=object, button=lambda *a, **k: (lambda fn: fn), Button=object)
    discord_mod.ButtonStyle = SimpleNamespace(success=1, primary=2, secondary=2, danger=3, green=1, grey=2, blurple=2, red=3)
    discord_mod.Color = SimpleNamespace(orange=lambda: 1, green=lambda: 2, blue=lambda: 3, red=lambda: 4, purple=lambda: 5)
    discord_mod.Interaction = object
    discord_mod.Embed = MagicMock
    discord_mod.app_commands = SimpleNamespace(
        describe=lambda **kwargs: (lambda fn: fn),
        choices=lambda **kwargs: (lambda fn: fn),
        Choice=lambda **kwargs: SimpleNamespace(**kwargs),
    )

    ext_mod = MagicMock()
    commands_mod = MagicMock()
    commands_mod.Bot = MagicMock
    ext_mod.commands = commands_mod

    sys.modules.setdefault("discord", discord_mod)
    sys.modules.setdefault("discord.ext", ext_mod)
    sys.modules.setdefault("discord.ext.commands", commands_mod)


_ensure_discord_mock()

from gateway.platforms.discord import DiscordAdapter  # noqa: E402


@pytest.fixture()
def adapter_factory():
    """Factory to create DiscordAdapter with custom reply_to_mode."""
    def create(reply_to_mode: str = "first"):
        config = PlatformConfig(enabled=True, token="test-token", reply_to_mode=reply_to_mode)
        return DiscordAdapter(config)
    return create


class TestReplyToModeConfig:
    """Tests for reply_to_mode configuration loading."""

    def test_default_mode_is_first(self, adapter_factory):
        adapter = adapter_factory()
        assert adapter._reply_to_mode == "first"

    def test_off_mode(self, adapter_factory):
        adapter = adapter_factory(reply_to_mode="off")
        assert adapter._reply_to_mode == "off"

    def test_first_mode(self, adapter_factory):
        adapter = adapter_factory(reply_to_mode="first")
        assert adapter._reply_to_mode == "first"

    def test_all_mode(self, adapter_factory):
        adapter = adapter_factory(reply_to_mode="all")
        assert adapter._reply_to_mode == "all"

    def test_invalid_mode_stored_as_is(self, adapter_factory):
        """Invalid modes are stored but send() handles them gracefully."""
        adapter = adapter_factory(reply_to_mode="invalid")
        assert adapter._reply_to_mode == "invalid"

    def test_none_mode_defaults_to_first(self):
        config = PlatformConfig(enabled=True, token="test-token")
        adapter = DiscordAdapter(config)
        assert adapter._reply_to_mode == "first"

    def test_empty_string_mode_defaults_to_first(self):
        config = PlatformConfig(enabled=True, token="test-token", reply_to_mode="")
        adapter = DiscordAdapter(config)
        assert adapter._reply_to_mode == "first"


def _make_discord_adapter(reply_to_mode: str = "first"):
    """Create a DiscordAdapter with mocked client and channel for send() tests."""
    config = PlatformConfig(enabled=True, token="test-token", reply_to_mode=reply_to_mode)
    adapter = DiscordAdapter(config)

    # Mock the Discord client and channel
    mock_channel = AsyncMock()
    ref_message = MagicMock()
    mock_channel.fetch_message = AsyncMock(return_value=ref_message)

    sent_msg = MagicMock()
    sent_msg.id = 42
    mock_channel.send = AsyncMock(return_value=sent_msg)

    mock_client = MagicMock()
    mock_client.get_channel = MagicMock(return_value=mock_channel)

    adapter._client = mock_client
    return adapter, mock_channel, ref_message


class TestSendWithReplyToMode:
    """Tests for send() method respecting reply_to_mode."""

    @pytest.mark.asyncio
    async def test_off_mode_no_reply_reference(self):
        adapter, channel, ref_msg = _make_discord_adapter("off")
        adapter.truncate_message = lambda content, max_len, **kw: ["chunk1", "chunk2", "chunk3"]

        await adapter.send("12345", "test content", reply_to="999")

        # Should never try to fetch the reference message
        channel.fetch_message.assert_not_called()
        # All chunks sent without reference
        for call in channel.send.call_args_list:
            assert call.kwargs.get("reference") is None

    @pytest.mark.asyncio
    async def test_first_mode_only_first_chunk_references(self):
        adapter, channel, ref_msg = _make_discord_adapter("first")
        adapter.truncate_message = lambda content, max_len, **kw: ["chunk1", "chunk2", "chunk3"]

        await adapter.send("12345", "test content", reply_to="999")

        # Should fetch the reference message
        channel.fetch_message.assert_called_once_with(999)
        calls = channel.send.call_args_list
        assert len(calls) == 3
        assert calls[0].kwargs.get("reference") is ref_msg
        assert calls[1].kwargs.get("reference") is None
        assert calls[2].kwargs.get("reference") is None

    @pytest.mark.asyncio
    async def test_all_mode_all_chunks_reference(self):
        adapter, channel, ref_msg = _make_discord_adapter("all")
        adapter.truncate_message = lambda content, max_len, **kw: ["chunk1", "chunk2", "chunk3"]

        await adapter.send("12345", "test content", reply_to="999")

        channel.fetch_message.assert_called_once_with(999)
        calls = channel.send.call_args_list
        assert len(calls) == 3
        for call in calls:
            assert call.kwargs.get("reference") is ref_msg

    @pytest.mark.asyncio
    async def test_no_reply_to_param_no_reference(self):
        adapter, channel, ref_msg = _make_discord_adapter("all")
        adapter.truncate_message = lambda content, max_len, **kw: ["chunk1", "chunk2"]

        await adapter.send("12345", "test content", reply_to=None)

        channel.fetch_message.assert_not_called()
        for call in channel.send.call_args_list:
            assert call.kwargs.get("reference") is None

    @pytest.mark.asyncio
    async def test_single_chunk_respects_first_mode(self):
        adapter, channel, ref_msg = _make_discord_adapter("first")
        adapter.truncate_message = lambda content, max_len, **kw: ["single chunk"]

        await adapter.send("12345", "test", reply_to="999")

        calls = channel.send.call_args_list
        assert len(calls) == 1
        assert calls[0].kwargs.get("reference") is ref_msg

    @pytest.mark.asyncio
    async def test_single_chunk_off_mode(self):
        adapter, channel, ref_msg = _make_discord_adapter("off")
        adapter.truncate_message = lambda content, max_len, **kw: ["single chunk"]

        await adapter.send("12345", "test", reply_to="999")

        channel.fetch_message.assert_not_called()
        calls = channel.send.call_args_list
        assert len(calls) == 1
        assert calls[0].kwargs.get("reference") is None

    @pytest.mark.asyncio
    async def test_invalid_mode_falls_back_to_first_behavior(self):
        """Invalid mode behaves like 'first' — only first chunk gets reference."""
        adapter, channel, ref_msg = _make_discord_adapter("banana")
        adapter.truncate_message = lambda content, max_len, **kw: ["chunk1", "chunk2"]

        await adapter.send("12345", "test", reply_to="999")

        calls = channel.send.call_args_list
        assert len(calls) == 2
        assert calls[0].kwargs.get("reference") is ref_msg
        assert calls[1].kwargs.get("reference") is None


class TestConfigSerialization:
    """Tests for reply_to_mode serialization (shared with Telegram)."""

    def test_to_dict_includes_reply_to_mode(self):
        config = PlatformConfig(enabled=True, token="test", reply_to_mode="all")
        result = config.to_dict()
        assert result["reply_to_mode"] == "all"

    def test_from_dict_loads_reply_to_mode(self):
        data = {"enabled": True, "token": "***", "reply_to_mode": "off"}
        config = PlatformConfig.from_dict(data)
        assert config.reply_to_mode == "off"

    def test_from_dict_defaults_to_first(self):
        data = {"enabled": True, "token": "***"}
        config = PlatformConfig.from_dict(data)
        assert config.reply_to_mode == "first"


class TestEnvVarOverride:
    """Tests for DISCORD_REPLY_TO_MODE environment variable override."""

    def _make_config(self):
        config = GatewayConfig()
        config.platforms[Platform.DISCORD] = PlatformConfig(enabled=True, token="test")
        return config

    def test_env_var_sets_off_mode(self):
        config = self._make_config()
        with patch.dict(os.environ, {"DISCORD_REPLY_TO_MODE": "off"}, clear=False):
            _apply_env_overrides(config)
        assert config.platforms[Platform.DISCORD].reply_to_mode == "off"

    def test_env_var_sets_all_mode(self):
        config = self._make_config()
        with patch.dict(os.environ, {"DISCORD_REPLY_TO_MODE": "all"}, clear=False):
            _apply_env_overrides(config)
        assert config.platforms[Platform.DISCORD].reply_to_mode == "all"

    def test_env_var_case_insensitive(self):
        config = self._make_config()
        with patch.dict(os.environ, {"DISCORD_REPLY_TO_MODE": "ALL"}, clear=False):
            _apply_env_overrides(config)
        assert config.platforms[Platform.DISCORD].reply_to_mode == "all"

    def test_env_var_invalid_value_ignored(self):
        config = self._make_config()
        with patch.dict(os.environ, {"DISCORD_REPLY_TO_MODE": "banana"}, clear=False):
            _apply_env_overrides(config)
        assert config.platforms[Platform.DISCORD].reply_to_mode == "first"

    def test_env_var_empty_value_ignored(self):
        config = self._make_config()
        with patch.dict(os.environ, {"DISCORD_REPLY_TO_MODE": ""}, clear=False):
            _apply_env_overrides(config)
        assert config.platforms[Platform.DISCORD].reply_to_mode == "first"

    def test_env_var_creates_platform_config_if_missing(self):
        """DISCORD_REPLY_TO_MODE creates PlatformConfig even without DISCORD_BOT_TOKEN."""
        config = GatewayConfig()
        assert Platform.DISCORD not in config.platforms
        with patch.dict(os.environ, {"DISCORD_REPLY_TO_MODE": "off"}, clear=False):
            _apply_env_overrides(config)
        assert Platform.DISCORD in config.platforms
        assert config.platforms[Platform.DISCORD].reply_to_mode == "off"
