"""Tests for `hermes fallback` — chain reading, add/remove/clear, legacy migration."""
from __future__ import annotations

import types
from pathlib import Path
from unittest.mock import patch

import pytest
import yaml


# ---------------------------------------------------------------------------
# Shared fixture — isolate HERMES_HOME so save_config writes to tmp_path
# ---------------------------------------------------------------------------

@pytest.fixture()
def isolated_home(tmp_path, monkeypatch):
    home = tmp_path / ".hermes"
    home.mkdir(exist_ok=True)
    monkeypatch.setenv("HERMES_HOME", str(home))
    return tmp_path


def _write_config(home: Path, data: dict) -> None:
    config_path = home / ".hermes" / "config.yaml"
    config_path.write_text(yaml.safe_dump(data), encoding="utf-8")


def _read_config(home: Path) -> dict:
    config_path = home / ".hermes" / "config.yaml"
    return yaml.safe_load(config_path.read_text(encoding="utf-8")) or {}


# ---------------------------------------------------------------------------
# _read_chain / _write_chain
# ---------------------------------------------------------------------------

class TestReadChain:
    def test_returns_empty_list_when_unset(self):
        from hermes_cli.fallback_cmd import _read_chain
        assert _read_chain({}) == []

    def test_reads_new_list_format(self):
        from hermes_cli.fallback_cmd import _read_chain
        cfg = {
            "fallback_providers": [
                {"provider": "openrouter", "model": "anthropic/claude-sonnet-4.6"},
                {"provider": "nous", "model": "Hermes-4-Llama-3.1-405B"},
            ]
        }
        assert _read_chain(cfg) == [
            {"provider": "openrouter", "model": "anthropic/claude-sonnet-4.6"},
            {"provider": "nous", "model": "Hermes-4-Llama-3.1-405B"},
        ]


    def test_returns_copies_not_aliases(self):
        from hermes_cli.fallback_cmd import _read_chain
        cfg = {"fallback_providers": [{"provider": "nous", "model": "foo"}]}
        result = _read_chain(cfg)
        result[0]["provider"] = "mutated"
        assert cfg["fallback_providers"][0]["provider"] == "nous"


# ---------------------------------------------------------------------------
# _extract_fallback_from_model_cfg
# ---------------------------------------------------------------------------

class TestExtractFallback:
    def test_extracts_from_default_field(self):
        from hermes_cli.fallback_cmd import _extract_fallback_from_model_cfg
        model_cfg = {"provider": "openrouter", "default": "anthropic/claude-sonnet-4.6"}
        assert _extract_fallback_from_model_cfg(model_cfg) == {
            "provider": "openrouter",
            "model": "anthropic/claude-sonnet-4.6",
        }


    def test_returns_none_without_model(self):
        from hermes_cli.fallback_cmd import _extract_fallback_from_model_cfg
        assert _extract_fallback_from_model_cfg({"provider": "openrouter"}) is None


# ---------------------------------------------------------------------------
# cmd_fallback_list
# ---------------------------------------------------------------------------

class TestListCommand:
    def test_list_empty(self, isolated_home, capsys):
        _write_config(isolated_home, {})
        from hermes_cli.fallback_cmd import cmd_fallback_list
        cmd_fallback_list(types.SimpleNamespace())
        out = capsys.readouterr().out
        assert "No fallback providers configured" in out
        assert "hermes fallback add" in out

    def test_list_with_entries(self, isolated_home, capsys):
        _write_config(isolated_home, {
            "model": {"provider": "anthropic", "default": "claude-sonnet-4-6"},
            "fallback_providers": [
                {"provider": "openrouter", "model": "anthropic/claude-sonnet-4.6"},
                {"provider": "nous", "model": "Hermes-4"},
            ],
        })
        from hermes_cli.fallback_cmd import cmd_fallback_list
        cmd_fallback_list(types.SimpleNamespace())
        out = capsys.readouterr().out
        assert "Fallback chain (2 entries)" in out
        assert "anthropic/claude-sonnet-4.6" in out
        assert "Hermes-4" in out
        # Primary should be shown too
        assert "claude-sonnet-4-6" in out


# ---------------------------------------------------------------------------
# cmd_fallback_add — mock select_provider_and_model
# ---------------------------------------------------------------------------

class TestAddCommand:
    def test_auth_snapshot_failure_aborts_before_picker(self):
        from hermes_cli import fallback_cmd

        picker = object()
        with patch(
            "hermes_cli.auth._load_auth_store",
            side_effect=OSError("auth read failed"),
        ), patch(
            "hermes_cli.main.select_provider_and_model",
            picker,
        ), patch("hermes_cli.main._require_tty"):
            with pytest.raises(OSError, match="auth read failed"):
                fallback_cmd.cmd_fallback_add(types.SimpleNamespace())

    def test_add_appends_new_entry(self, isolated_home, capsys):
        _write_config(isolated_home, {
            "model": {"provider": "anthropic", "default": "claude-sonnet-4-6"},
        })

        def fake_picker(args=None):
            # Simulate what the real picker does: writes the selection to config["model"]
            from hermes_cli.config import load_config, save_config
            cfg = load_config()
            cfg["model"] = {
                "provider": "openrouter",
                "default": "anthropic/claude-sonnet-4.6",
                "base_url": "https://openrouter.ai/api/v1",
                "api_mode": "chat_completions",
            }
            save_config(cfg)

        with patch("hermes_cli.main.select_provider_and_model", side_effect=fake_picker), \
                patch("hermes_cli.main._require_tty"):
            from hermes_cli.fallback_cmd import cmd_fallback_add
            cmd_fallback_add(types.SimpleNamespace())

        cfg = _read_config(isolated_home)
        # Primary is preserved
        assert cfg["model"]["provider"] == "anthropic"
        assert cfg["model"]["default"] == "claude-sonnet-4-6"
        # Fallback was appended
        assert cfg["fallback_providers"] == [
            {
                "provider": "openrouter",
                "model": "anthropic/claude-sonnet-4.6",
                "base_url": "https://openrouter.ai/api/v1",
                "api_mode": "chat_completions",
            }
        ]
        out = capsys.readouterr().out
        assert "Added fallback" in out


    def test_add_rejects_same_as_primary(self, isolated_home, capsys):
        _write_config(isolated_home, {
            "model": {"provider": "openrouter", "default": "gpt-5.4"},
        })

        def fake_picker(args=None):
            # User picks the same thing that's already the primary
            from hermes_cli.config import load_config, save_config
            cfg = load_config()
            cfg["model"] = {"provider": "openrouter", "default": "gpt-5.4"}
            save_config(cfg)

        with patch("hermes_cli.main.select_provider_and_model", side_effect=fake_picker), \
                patch("hermes_cli.main._require_tty"):
            from hermes_cli.fallback_cmd import cmd_fallback_add
            cmd_fallback_add(types.SimpleNamespace())

        cfg = _read_config(isolated_home)
        assert "fallback_providers" not in cfg or cfg["fallback_providers"] == []
        out = capsys.readouterr().out
        assert "matches the current primary" in out

    def test_add_preserves_primary_when_picker_changes_it(self, isolated_home):
        """The picker mutates config["model"]; fallback_add must restore the primary."""
        _write_config(isolated_home, {
            "model": {
                "provider": "anthropic",
                "default": "claude-sonnet-4-6",
                "base_url": "https://api.anthropic.com",
                "api_mode": "anthropic_messages",
            },
        })

        def fake_picker(args=None):
            from hermes_cli.config import load_config, save_config
            cfg = load_config()
            cfg["model"] = {
                "provider": "openrouter",
                "default": "anthropic/claude-sonnet-4.6",
                "base_url": "https://openrouter.ai/api/v1",
                "api_mode": "chat_completions",
            }
            cfg["custom_providers"] = [
                {
                    "name": "Picker-created endpoint",
                    "base_url": "https://picker.example/v1",
                    "model": "picker-model",
                }
            ]
            save_config(cfg)

        with patch("hermes_cli.main.select_provider_and_model", side_effect=fake_picker), \
                patch("hermes_cli.main._require_tty"):
            from hermes_cli.fallback_cmd import cmd_fallback_add
            cmd_fallback_add(types.SimpleNamespace())

        cfg = _read_config(isolated_home)
        # Primary exactly as it was
        assert cfg["model"]["provider"] == "anthropic"
        assert cfg["model"]["default"] == "claude-sonnet-4-6"
        assert cfg["model"]["base_url"] == "https://api.anthropic.com"
        assert cfg["model"]["api_mode"] == "anthropic_messages"
        # Fallback added
        assert len(cfg["fallback_providers"]) == 1
        assert cfg["fallback_providers"][0]["provider"] == "openrouter"
        assert cfg["custom_providers"] == [
            {
                "name": "Picker-created endpoint",
                "base_url": "https://picker.example/v1",
                "model": "picker-model",
            }
        ]

    def test_post_picker_config_read_failure_restores_route(self):
        from hermes_cli import fallback_cmd

        primary_model = {
            "provider": "anthropic",
            "default": "claude-sonnet-4-6",
        }
        post_read_error = OSError("post-picker config read failed")
        reads = iter([{"model": primary_model}, post_read_error])

        def load_config():
            value = next(reads)
            if isinstance(value, BaseException):
                raise value
            return value

        restore_calls = []
        with patch("hermes_cli.config.load_config", side_effect=load_config), patch(
            "hermes_cli.main._require_tty"
        ), patch("hermes_cli.main.select_provider_and_model"), patch.object(
            fallback_cmd, "_snapshot_auth_active_provider", return_value="old-provider"
        ), patch.object(
            fallback_cmd,
            "_restore_primary_route",
            side_effect=lambda model, provider: restore_calls.append((model, provider)),
        ):
            with pytest.raises(OSError) as exc_info:
                fallback_cmd.cmd_fallback_add(types.SimpleNamespace())

        assert exc_info.value is post_read_error
        assert restore_calls == [(primary_model, "old-provider")]

    @pytest.mark.parametrize(
        ("failure_type", "message"),
        [
            (OSError, "config write failed"),
            (KeyboardInterrupt, "config restore interrupted"),
        ],
    )
    def test_restore_attempts_auth_after_model_restore_failure(
        self, failure_type, message
    ):
        from hermes_cli import fallback_cmd

        auth_calls = []
        with patch.object(
            fallback_cmd,
            "_restore_model_cfg",
            side_effect=failure_type(message),
        ), patch.object(
            fallback_cmd,
            "_restore_auth_active_provider",
            side_effect=lambda value: auth_calls.append(value),
        ):
            with pytest.raises(RuntimeError, match=message):
                fallback_cmd._restore_primary_route("old-model", "old-provider")

        assert auth_calls == ["old-provider"]

    def test_restore_preserves_absent_active_provider(self):
        from contextlib import nullcontext

        from hermes_cli import auth, fallback_cmd

        store = {"version": 1, "providers": {}}

        def save_auth(value):
            store.clear()
            store.update(value)

        with patch.object(auth, "_load_auth_store", lambda: dict(store)), patch.object(
            auth, "_save_auth_store", save_auth
        ), patch.object(auth, "_auth_store_lock", nullcontext):
            before = fallback_cmd._snapshot_auth_active_provider()
            fallback_cmd._restore_auth_active_provider(before)

        assert "active_provider" not in store

    def test_picker_failure_restores_persisted_primary_without_masking_error(
        self, isolated_home
    ):
        from hermes_cli import fallback_cmd

        primary_model = {
            "provider": "anthropic",
            "default": "claude-sonnet-4-6",
            "base_url": "https://api.anthropic.com",
            "api_mode": "anthropic_messages",
        }
        _write_config(isolated_home, {"model": primary_model, "theme": "midnight"})
        picker_error = LookupError("picker failed")

        def failing_picker(args=None):
            from hermes_cli.config import load_config, save_config

            cfg = load_config()
            cfg["model"] = {
                "provider": "openrouter",
                "default": "anthropic/claude-sonnet-4.6",
                "base_url": "https://openrouter.ai/api/v1",
                "api_mode": "chat_completions",
            }
            save_config(cfg)
            raise picker_error

        with patch(
            "hermes_cli.main.select_provider_and_model",
            side_effect=failing_picker,
        ), patch("hermes_cli.main._require_tty"):
            with pytest.raises(LookupError, match="picker failed") as exc_info:
                fallback_cmd.cmd_fallback_add(types.SimpleNamespace())

        assert exc_info.value is picker_error
        persisted = _read_config(isolated_home)
        assert persisted["model"] == primary_model
        assert persisted["theme"] == "midnight"


# ---------------------------------------------------------------------------
# cmd_fallback_remove
# ---------------------------------------------------------------------------

class TestRemoveCommand:

    def test_remove_selected_entry(self, isolated_home, capsys):
        _write_config(isolated_home, {
            "fallback_providers": [
                {"provider": "openrouter", "model": "gpt-5.4"},
                {"provider": "nous", "model": "Hermes-4"},
                {"provider": "anthropic", "model": "claude-sonnet-4-6"},
            ],
        })

        # Picker returns index 1 (the middle entry, "nous / Hermes-4")
        with patch("hermes_cli.setup._curses_prompt_choice", return_value=1):
            from hermes_cli.fallback_cmd import cmd_fallback_remove
            cmd_fallback_remove(types.SimpleNamespace())

        cfg = _read_config(isolated_home)
        assert cfg["fallback_providers"] == [
            {"provider": "openrouter", "model": "gpt-5.4"},
            {"provider": "anthropic", "model": "claude-sonnet-4-6"},
        ]
        out = capsys.readouterr().out
        assert "Removed fallback" in out
        assert "Hermes-4" in out


# ---------------------------------------------------------------------------
# cmd_fallback_clear
# ---------------------------------------------------------------------------

class TestClearCommand:

    def test_clear_with_confirmation(self, isolated_home, capsys, monkeypatch):
        _write_config(isolated_home, {
            "fallback_providers": [
                {"provider": "openrouter", "model": "gpt-5.4"},
                {"provider": "nous", "model": "Hermes-4"},
            ],
        })
        monkeypatch.setattr("builtins.input", lambda *a, **kw: "y")
        from hermes_cli.fallback_cmd import cmd_fallback_clear
        cmd_fallback_clear(types.SimpleNamespace())

        cfg = _read_config(isolated_home)
        assert cfg.get("fallback_providers") == []
        out = capsys.readouterr().out
        assert "Fallback chain cleared" in out


# ---------------------------------------------------------------------------
# cmd_fallback dispatcher
# ---------------------------------------------------------------------------

class TestDispatcher:


    def test_unknown_subcommand_exits(self, isolated_home):
        _write_config(isolated_home, {})
        from hermes_cli.fallback_cmd import cmd_fallback
        with pytest.raises(SystemExit):
            cmd_fallback(types.SimpleNamespace(fallback_command="nope"))


# ---------------------------------------------------------------------------
# argparse wiring — verify the subparser is registered
# ---------------------------------------------------------------------------

class TestArgparseWiring:
    """Verify `hermes fallback` is wired into main.py's argparse tree.

    main() builds the parser inline, so we invoke main([...]) via subprocess
    with --help to introspect registered subcommands without side effects.
    """

    def test_fallback_help_lists_subcommands(self):
        import subprocess
        import sys
        result = subprocess.run(
            [sys.executable, "-m", "hermes_cli.main", "fallback", "--help"],
            capture_output=True,
            text=True,
            timeout=30,
        )
        # --help exits 0
        assert result.returncode == 0, f"stderr: {result.stderr}"
        out = result.stdout + result.stderr
        # All four subcommands should appear in help
        assert "list" in out
        assert "add" in out
        assert "remove" in out
        assert "clear" in out