"""Tests for install_python_stack._build_uv_cmd torch-backend handling."""

from __future__ import annotations

import glob
import importlib
import os
import sys
import tempfile
from pathlib import Path
from unittest import mock

import pytest

STUDIO_DIR = Path(__file__).resolve().parents[2] / "studio"
sys.path.insert(0, str(STUDIO_DIR))

import install_python_stack as ips


class TestBuildUvCmdTorchBackend:
    """Verify _build_uv_cmd only adds --torch-backend when UV_TORCH_BACKEND is set."""

    def _call(self, args: tuple[str, ...] = ()) -> list[str]:
        return ips._build_uv_cmd(args)

    def test_default_no_torch_backend(self):
        """Without UV_TORCH_BACKEND env var, no --torch-backend flag."""
        env = os.environ.copy()
        env.pop("UV_TORCH_BACKEND", None)
        with mock.patch.dict(os.environ, env, clear = True):
            cmd = self._call(("somepackage",))
        assert not any(
            a.startswith("--torch-backend") for a in cmd
        ), f"--torch-backend should not appear by default, got: {cmd}"

    def test_uv_torch_backend_auto(self):
        """UV_TORCH_BACKEND=auto adds --torch-backend=auto."""
        with mock.patch.dict(os.environ, {"UV_TORCH_BACKEND": "auto"}):
            cmd = self._call(("somepackage",))
        assert "--torch-backend=auto" in cmd

    def test_uv_torch_backend_cpu(self):
        """UV_TORCH_BACKEND=cpu adds --torch-backend=cpu."""
        with mock.patch.dict(os.environ, {"UV_TORCH_BACKEND": "cpu"}):
            cmd = self._call(("somepackage",))
        assert "--torch-backend=cpu" in cmd

    def test_uv_torch_backend_empty(self):
        """UV_TORCH_BACKEND="" (empty string) should NOT add --torch-backend."""
        with mock.patch.dict(os.environ, {"UV_TORCH_BACKEND": ""}):
            cmd = self._call(("somepackage",))
        assert not any(
            a.startswith("--torch-backend") for a in cmd
        ), f"Empty UV_TORCH_BACKEND should not add flag, got: {cmd}"

    def test_uv_torch_backend_skipped_for_pinned_index(self):
        """A pinned-index command must NOT get --torch-backend: uv's torch backend
        redirects torch resolution to its own per-backend index even when
        --index-url is given (verified: cu128 pin + backend cpu installs
        torch+cpu), defeating the pin."""
        for pin_flag in ("--index-url", "--default-index"):
            with mock.patch.dict(os.environ, {"UV_TORCH_BACKEND": "cpu"}):
                cmd = self._call(("torch", pin_flag, "https://download.pytorch.org/whl/cu128"))
            assert not any(
                a.startswith("--torch-backend") for a in cmd
            ), f"{pin_flag} command must not carry --torch-backend, got: {cmd}"

    def test_uv_torch_backend_kept_for_unpinned(self):
        """Non-pinned commands still honour UV_TORCH_BACKEND."""
        with mock.patch.dict(os.environ, {"UV_TORCH_BACKEND": "cpu"}):
            cmd = self._call(("somepackage",))
        assert "--torch-backend=cpu" in cmd


class TestUvSafePath:
    """_uv_safe_path hands uv a space-free `-c`/`-r` path (issue #6503)."""

    def test_passthrough_when_no_space(self):
        """A path without a space is returned unchanged on every platform."""
        p = "/tmp/plain/constraints.txt"
        assert ips._uv_safe_path(p) == p

    @pytest.mark.skipif(ips.IS_WINDOWS, reason = "POSIX temp-copy fallback")
    def test_posix_space_path_returns_spacefree_copy(self, tmp_path):
        src = tmp_path / "Open Source" / "constraints.txt"
        src.parent.mkdir(parents = True)
        src.write_text("torch>=2.6\n")

        out = ips._uv_safe_path(str(src))

        assert " " not in out, f"uv-safe path still has a space: {out!r}"
        assert out != str(src)
        assert Path(out).read_text() == "torch>=2.6\n"

    @pytest.mark.skipif(ips.IS_WINDOWS, reason = "POSIX temp-copy fallback")
    def test_posix_missing_file_falls_back_to_original(self):
        """No file to copy -> return the original path rather than raise."""
        p = "/nonexistent dir/constraints.txt"
        assert ips._uv_safe_path(p) == p


class TestUvSafePathHardening:
    """Edge cases for uv_safe_path + the UV_OVERRIDE channel (issue #6503)."""

    @pytest.mark.skipif(ips.IS_WINDOWS, reason = "POSIX temp-copy fallback")
    def test_tmpdir_with_space_falls_back(self, tmp_path, monkeypatch):
        """A space in the temp root itself -> fall back to the original path."""
        from backend.utils import uv_path_safety as uvps

        spaced = tmp_path / "tmp dir with space"
        spaced.mkdir()
        monkeypatch.setattr(uvps.tempfile, "mkdtemp", lambda *a, **k: str(spaced))
        src = tmp_path / "Open Source" / "constraints.txt"
        src.parent.mkdir(parents = True)
        src.write_text("idna\n")
        assert uvps.uv_safe_path(str(src)) == str(src)

    @pytest.mark.skipif(ips.IS_WINDOWS, reason = "POSIX temp-copy fallback")
    def test_no_temp_dir_leak_on_copy_failure(self, tmp_path, monkeypatch):
        """A copyfile failure after mkdtemp must not orphan the temp dir."""
        from backend.utils import uv_path_safety as uvps

        src = tmp_path / "Open Source" / "constraints.txt"
        src.parent.mkdir(parents = True)
        src.write_text("idna\n")
        pattern = os.path.join(tempfile.gettempdir(), "unsloth_uv_*")
        before = set(glob.glob(pattern))

        def boom(*a, **k):
            raise OSError("boom")

        monkeypatch.setattr(uvps.shutil, "copyfile", boom)
        out = uvps.uv_safe_path(str(src))

        assert out == str(src)
        assert set(glob.glob(pattern)) == before

    @pytest.mark.skipif(ips.IS_WINDOWS, reason = "POSIX temp-copy fallback")
    def test_cleanup_removes_and_clears_registry(self, tmp_path):
        """The atexit-registered cleanup removes the copies and empties the list."""
        from backend.utils import uv_path_safety as uvps

        src = tmp_path / "Open Source" / "constraints.txt"
        src.parent.mkdir(parents = True)
        src.write_text("idna\n")
        out = uvps.uv_safe_path(str(src))
        tmp_dir = Path(out).parent
        assert tmp_dir.is_dir() and str(tmp_dir) in uvps._UV_SAFE_PATH_TMPDIRS

        uvps._cleanup_uv_safe_path_tmpdirs()

        assert not tmp_dir.exists()
        assert uvps._UV_SAFE_PATH_TMPDIRS == []

    @pytest.mark.skipif(ips.IS_WINDOWS, reason = "POSIX temp-copy fallback")
    def test_uv_override_value_is_space_safe(self, tmp_path):
        """The value stored for UV_OVERRIDE must be space-free."""
        from backend.utils import uv_path_safety as uvps

        overrides = tmp_path / "Open Source" / "overrides-darwin-arm64.txt"
        overrides.parent.mkdir(parents = True)
        overrides.write_text("transformers>=4.57.6\n")

        value = uvps.uv_safe_path(overrides)

        assert " " not in value
        assert Path(value).read_text() == "transformers>=4.57.6\n"


class TestPinnedIndexClearsUvEnv:
    """A pinned torch install (--index-url / --default-index) must neutralise an
    inherited UV_INDEX / UV_EXTRA_INDEX_URL so the pinned wheel index wins.

    uv treats the default index (--index-url / --default-index) as LOWEST priority,
    so an inherited UV_INDEX / UV_EXTRA_INDEX_URL (a corporate/CPU mirror) would be
    searched first and, under uv's default first-index strategy, resolve torch from
    the wrong mirror -- after which the marker records a wheel index that was never
    used. install.sh (#6898), install.ps1 and setup.ps1 already clear these for
    pinned installs; install_python_stack must match (parity across all installers).
    """

    UV_VARS = ("UV_DEFAULT_INDEX", "UV_INDEX_URL", "UV_INDEX", "UV_EXTRA_INDEX_URL")

    def test_pinned_index_url_strips_uv_index_vars(self):
        cmd = [
            "uv",
            "pip",
            "install",
            "--force-reinstall",
            "torch",
            "torchvision",
            "torchaudio",
            "--index-url",
            "https://download.pytorch.org/whl/cu128",
        ]
        with mock.patch.dict(
            os.environ,
            {
                "UV_INDEX": "https://mirror.corp/simple",
                "UV_EXTRA_INDEX_URL": "https://mirror.corp/extra",
                "UV_INDEX_URL": "https://mirror.corp/root",
                "UV_DEFAULT_INDEX": "https://mirror.corp/default",
            },
        ):
            env = ips._install_env_for_cmd(cmd)
        assert env is not None, "a --index-url install must run with a scrubbed env"
        for var in self.UV_VARS:
            assert var not in env, f"{var} must be cleared for a pinned-index install"

    def test_pinned_default_index_strips_uv_index_vars(self):
        # --default-index must be gated too (matches install.sh / install.ps1).
        cmd = ["uv", "pip", "install", "torch", "--default-index", "https://x/cu126"]
        with mock.patch.dict(os.environ, {"UV_INDEX": "https://mirror.corp/simple"}):
            env = ips._install_env_for_cmd(cmd)
        assert env is not None
        assert "UV_INDEX" not in env

    def test_non_pinned_install_keeps_user_mirror(self):
        # A plain install (no --index-url) must NOT scrub the env, so a user's mirror
        # still applies to base packages.
        cmd = ["uv", "pip", "install", "unsloth", "unsloth-zoo"]
        with mock.patch.dict(os.environ, {"UV_INDEX": "https://mirror.corp/simple"}):
            env = ips._install_env_for_cmd(cmd)
        assert env is None, "non-pinned installs must inherit the caller env unchanged"

    def test_scrubbed_env_preserves_other_vars(self):
        cmd = ["uv", "pip", "install", "torch", "--index-url", "https://x/cu128"]
        with mock.patch.dict(
            os.environ,
            {"UV_INDEX": "https://mirror.corp/simple", "PATH_SENTINEL_XYZ": "keepme"},
        ):
            env = ips._install_env_for_cmd(cmd)
        assert env is not None
        assert env.get("PATH_SENTINEL_XYZ") == "keepme", "only uv index vars are removed"

    def test_pinned_cmd_strips_pip_extra_index_url(self):
        """PIP_EXTRA_INDEX_URL is stripped for pinned commands so the pip
        fallback cannot satisfy torch from an inherited extra index."""
        with mock.patch.dict(os.environ, {"PIP_EXTRA_INDEX_URL": "https://mirror/simple"}):
            env = ips._install_env_for_cmd(
                ["pip", "install", "torch", "--index-url", "https://x/cu128"]
            )
        assert env is not None and "PIP_EXTRA_INDEX_URL" not in env

    def test_pinned_cmd_strips_uv_torch_backend(self):
        """UV_TORCH_BACKEND is stripped for pinned commands so uv cannot read it
        from the environment and reroute torch off the pinned index."""
        with mock.patch.dict(os.environ, {"UV_TORCH_BACKEND": "cpu"}):
            env = ips._install_env_for_cmd(
                ["uv", "pip", "install", "torch", "--index-url", "https://x/cu128"]
            )
        assert env is not None and "UV_TORCH_BACKEND" not in env

    def test_pinned_cmd_disables_uv_config_discovery(self):
        """A DISCOVERED uv.toml / pyproject [tool.uv] outranks the CLI pin too
        (verified with uv 0.10: [pip] torch-backend = "cpu" and a non-default
        [[index]] both resolve torch+cpu against an explicit --index-url /
        --default-index cu126 pin). Pinned commands must run with UV_NO_CONFIG=1
        and without an inherited UV_CONFIG_FILE."""
        with mock.patch.dict(os.environ, {"UV_CONFIG_FILE": "/etc/uv/uv.toml"}):
            env = ips._install_env_for_cmd(
                ["uv", "pip", "install", "torch", "--index-url", "https://x/cu128"]
            )
        assert env is not None
        assert env.get("UV_NO_CONFIG") == "1"
        assert "UV_CONFIG_FILE" not in env

    def test_pinned_cmd_disables_pip_config_files(self):
        """The pip FALLBACK honours user/site pip config files (pip config set
        global.extra-index-url) even with the PIP_* env vars stripped; pip loads
        NO configuration files when PIP_CONFIG_FILE is os.devnull. Harmless for
        uv, decisive for the fallback."""
        env = ips._install_env_for_cmd(
            ["uv", "pip", "install", "torch", "--index-url", "https://x/cu128"]
        )
        assert env is not None
        assert env.get("PIP_CONFIG_FILE") == os.devnull

    def test_non_pinned_cmd_keeps_uv_config_discovery(self):
        """Non-pinned installs inherit the caller env unchanged, so a user's uv
        configuration still applies to base packages."""
        env = ips._install_env_for_cmd(["uv", "pip", "install", "unsloth"])
        assert env is None