import json
from pathlib import Path

import api.config as config


def _reject_workspace_candidate(monkeypatch, candidate: Path) -> None:
    original_ensure = config._ensure_workspace_dir
    resolved_candidate = candidate.resolve()

    def wrapped(path: Path) -> bool:
        if path.expanduser().resolve() == resolved_candidate:
            return False
        return original_ensure(path)

    monkeypatch.setattr(config, "_ensure_workspace_dir", wrapped)


def test_resolve_default_workspace_falls_back_to_existing_home_work(monkeypatch, tmp_path):
    preferred = tmp_path / "work"
    preferred.mkdir()
    state_dir = tmp_path / "state"
    bad_candidate = tmp_path / "not-usable"

    monkeypatch.setattr(config, "HOME", tmp_path)
    monkeypatch.setattr(config, "STATE_DIR", state_dir)
    monkeypatch.delenv("HERMES_WEBUI_DEFAULT_WORKSPACE", raising=False)
    _reject_workspace_candidate(monkeypatch, bad_candidate)

    resolved = config.resolve_default_workspace(str(bad_candidate))

    assert resolved == preferred.resolve()



def test_save_settings_rewrites_bad_default_workspace_to_fallback(monkeypatch, tmp_path):
    preferred = tmp_path / "work"
    preferred.mkdir()
    state_dir = tmp_path / "state"
    settings_file = tmp_path / "settings.json"
    bad_candidate = tmp_path / "not-usable"

    monkeypatch.setattr(config, "HOME", tmp_path)
    monkeypatch.setattr(config, "STATE_DIR", state_dir)
    monkeypatch.setattr(config, "SETTINGS_FILE", settings_file)
    monkeypatch.setattr(config, "DEFAULT_WORKSPACE", preferred)
    monkeypatch.delenv("HERMES_WEBUI_DEFAULT_WORKSPACE", raising=False)
    _reject_workspace_candidate(monkeypatch, bad_candidate)

    saved = config.save_settings({"default_workspace": str(bad_candidate)})
    on_disk = json.loads(settings_file.read_text(encoding="utf-8"))

    assert saved["default_workspace"] == str(preferred.resolve())
    assert on_disk["default_workspace"] == str(preferred.resolve())


def test_resolve_default_workspace_creates_home_workspace_when_missing(monkeypatch, tmp_path):
    """When no preferred dir exists, resolve falls back to creating ~/workspace."""
    state_dir = tmp_path / "state"
    monkeypatch.setattr(config, "HOME", tmp_path)
    monkeypatch.setattr(config, "STATE_DIR", state_dir)
    monkeypatch.delenv("HERMES_WEBUI_DEFAULT_WORKSPACE", raising=False)
    # Neither ~/work nor ~/workspace exists yet
    resolved = config.resolve_default_workspace(None)
    assert resolved == (tmp_path / "workspace").resolve()
    assert resolved.is_dir()


def test_resolve_default_workspace_raises_when_all_candidates_fail(monkeypatch, tmp_path):
    """RuntimeError is raised when every candidate is unwritable."""
    import pytest
    state_dir = tmp_path / "state"
    monkeypatch.setattr(config, "HOME", tmp_path)
    monkeypatch.setattr(config, "STATE_DIR", state_dir)
    monkeypatch.delenv("HERMES_WEBUI_DEFAULT_WORKSPACE", raising=False)
    monkeypatch.setattr(config, "_ensure_workspace_dir", lambda path: False)

    with pytest.raises(RuntimeError, match="Could not create or access"):
        config.resolve_default_workspace(None)


def test_workspace_candidates_deduplicates_home_workspace(monkeypatch, tmp_path):
    """~/workspace must appear at most once in the candidates list even if it exists."""
    ws = tmp_path / "workspace"
    ws.mkdir()
    state_dir = tmp_path / "state"
    monkeypatch.setattr(config, "HOME", tmp_path)
    monkeypatch.setattr(config, "STATE_DIR", state_dir)
    monkeypatch.delenv("HERMES_WEBUI_DEFAULT_WORKSPACE", raising=False)
    candidates = config._workspace_candidates(None)
    paths = [str(p) for p in candidates]
    assert paths.count(str(ws.resolve())) <= 1, "~/workspace must not appear twice"


def test_env_var_workspace_takes_priority_over_passed_raw(monkeypatch, tmp_path):
    """HERMES_WEBUI_DEFAULT_WORKSPACE env var overrides a None raw arg but not a valid one."""
    env_ws = tmp_path / "env_workspace"
    env_ws.mkdir()
    state_dir = tmp_path / "state"
    monkeypatch.setattr(config, "HOME", tmp_path)
    monkeypatch.setattr(config, "STATE_DIR", state_dir)
    monkeypatch.setenv("HERMES_WEBUI_DEFAULT_WORKSPACE", str(env_ws))
    # When raw is None, env var should be used
    resolved = config.resolve_default_workspace(None)
    assert resolved == env_ws.resolve()


def test_ensure_workspace_dir_returns_false_for_unwritable_path(monkeypatch, tmp_path):
    """_ensure_workspace_dir returns False for a path that can't be created."""
    def fail_mkdir(self, mode=0o777, parents=False, exist_ok=False):
        raise PermissionError("simulated create failure")

    monkeypatch.setattr(Path, "mkdir", fail_mkdir)

    result = config._ensure_workspace_dir(tmp_path / "child")
    assert result is False


def test_env_var_wins_over_settings_json_on_startup(monkeypatch, tmp_path):
    """HERMES_WEBUI_DEFAULT_WORKSPACE must not be overridden by settings.json at startup.

    Regression for GitHub issue #609: Docker deployments set the env var to a
    volume mount, but settings.json from a previous container run used to
    silently win, reverting the files panel to the old path.
    """
    import json as _json
    import os as _os

    env_ws = tmp_path / "env_workspace"
    env_ws.mkdir()
    settings_ws = tmp_path / "settings_workspace"
    settings_ws.mkdir()
    state_dir = tmp_path / "state"
    state_dir.mkdir()
    settings_file = state_dir / "settings.json"
    settings_file.write_text(
        _json.dumps({"default_workspace": str(settings_ws)}), encoding="utf-8"
    )

    monkeypatch.setattr(config, "HOME", tmp_path)
    monkeypatch.setattr(config, "STATE_DIR", state_dir)
    monkeypatch.setattr(config, "SETTINGS_FILE", settings_file)
    # Simulate DEFAULT_WORKSPACE already set correctly from env var at import time
    monkeypatch.setattr(config, "DEFAULT_WORKSPACE", env_ws.resolve())
    monkeypatch.setenv("HERMES_WEBUI_DEFAULT_WORKSPACE", str(env_ws))

    # Execute the patched startup block logic inline — env var present → skip override
    current_ws = config.DEFAULT_WORKSPACE
    startup_settings = config.load_settings()
    if not _os.getenv("HERMES_WEBUI_DEFAULT_WORKSPACE"):
        # This branch must be skipped because env var is set
        current_ws = config.resolve_default_workspace(
            startup_settings.get("default_workspace")
        )

    # env var was set → the if block was skipped → env path wins over settings.json
    assert current_ws == env_ws.resolve(), (
        f"Expected {env_ws.resolve()}, got {current_ws}. "
        "settings.json must not override HERMES_WEBUI_DEFAULT_WORKSPACE."
    )