"""Tests for flow.core.template."""

import os

from flow.core.template import substitute, substitute_template


class TestSubstitute:
    def test_replaces_dollar_var(self):
        assert substitute("hello $NAME", {"NAME": "world"}) == "hello world"

    def test_replaces_braced_var(self):
        assert substitute("hello ${NAME}", {"NAME": "world"}) == "hello world"

    def test_falls_back_to_env(self, monkeypatch):
        monkeypatch.setenv("FOO", "bar")
        assert substitute("$FOO", {}) == "bar"

    def test_preserves_unknown_vars(self):
        assert substitute("$UNKNOWN", {}) == "$UNKNOWN"

    def test_non_string_passthrough(self):
        assert substitute(42, {}) == 42


class TestSubstituteTemplate:
    def test_replaces_double_braces(self):
        assert substitute_template("nvim-{{os}}", {"os": "linux"}) == "nvim-linux"

    def test_env_dot_notation(self, monkeypatch):
        monkeypatch.setenv("USER", "tomas")
        result = substitute_template("{{ env.USER }}", {"env": dict(os.environ)})
        assert result == "tomas"

    def test_nested_dict_lookup(self):
        ctx = {"platform": {"arch": "arm64"}}
        assert substitute_template("{{ platform.arch }}", ctx) == "arm64"

    def test_preserves_unknown_templates(self):
        assert substitute_template("{{ unknown }}", {}) == "{{ unknown }}"

    def test_non_string_passthrough(self):
        assert substitute_template(42, {}) == 42

    def test_whitespace_in_braces(self):
        assert substitute_template("{{  os  }}", {"os": "linux"}) == "linux"