from pathlib import Path

import pytest

import canned_prompts as cp


@pytest.fixture()
def package(tmp_path: Path) -> Path:
    pkg = tmp_path / "pkg"
    pkg.mkdir()
    (pkg / "prompt.yaml").write_text(
        """\
format: canned-prompt/v0.1
id: demo/hello
name: Hello
version: 1.0.0
summary: Say hello.
template: prompt.md
inputs:
  - name: person
    required: true
parameters:
  tone:
    type: enum
    values: [warm, formal]
    default: warm
""",
        encoding="utf-8",
    )
    (pkg / "prompt.md").write_text(
        "Say hello to {{ person }} in a {{ tone }} tone.\n", encoding="utf-8"
    )
    return pkg


def test_validate_and_render(package: Path) -> None:
    manifest = cp.validate_package(package)
    values = cp.resolve_values(manifest, {"person": "Ada"})
    rendered = cp.render_template((package / "prompt.md").read_text(), values)
    assert rendered == "Say hello to Ada in a warm tone.\n"


def test_missing_required_input_fails(package: Path) -> None:
    manifest = cp.validate_package(package)
    with pytest.raises(cp.CannedPromptError, match="missing required input"):
        cp.resolve_values(manifest, {})


def test_undeclared_placeholder_fails(package: Path) -> None:
    (package / "prompt.md").write_text("{{ missing }}\n", encoding="utf-8")
    with pytest.raises(cp.CannedPromptError, match="undeclared placeholders"):
        cp.validate_package(package)


def write_pkg(pkg: Path, manifest: str, template: str = "{{ greeting }}\n") -> Path:
    pkg.mkdir(exist_ok=True)
    (pkg / "prompt.yaml").write_text(manifest, encoding="utf-8")
    (pkg / "prompt.md").write_text(template, encoding="utf-8")
    return pkg


BASE = """\
format: canned-prompt/v0.1
id: demo/defaults
name: Defaults
version: 1.0.0
summary: Exercise input defaults.
template: prompt.md
"""


def test_static_default_fills_optional_input(tmp_path: Path) -> None:
    pkg = write_pkg(
        tmp_path / "p",
        BASE
        + """\
inputs:
  - name: greeting
    required: false
    default: "hello there"
""",
    )
    manifest = cp.validate_package(pkg)
    resolution = cp.resolve_inputs(manifest, {})
    assert resolution.values["greeting"] == "hello there"
    assert resolution.origins["greeting"] == "default"
    assert cp.render_template("{{ greeting }}", resolution.values) == "hello there"


def test_supplied_value_overrides_static_default(tmp_path: Path) -> None:
    pkg = write_pkg(
        tmp_path / "p",
        BASE
        + """\
inputs:
  - name: greeting
    required: false
    default: "hello there"
""",
    )
    manifest = cp.validate_package(pkg)
    resolution = cp.resolve_inputs(manifest, {"greeting": "hi"})
    assert resolution.values["greeting"] == "hi"
    assert resolution.origins["greeting"] == "supplied"


def test_derived_default_uses_static_fallback(tmp_path: Path) -> None:
    pkg = write_pkg(
        tmp_path / "p",
        BASE
        + """\
dependencies:
  prompts:
    - id: context/greeting
      version: 1.0.0
      requirement: generate
inputs:
  - name: greeting
    required: false
    default:
      derive: context/greeting
      value: "(none)"
""",
    )
    manifest = cp.validate_package(pkg)
    resolution = cp.resolve_inputs(manifest, {})
    assert resolution.values["greeting"] == "(none)"
    assert resolution.origins["greeting"] == "fallback (not derived)"
    assert resolution.underivable == []


def test_derived_default_without_fallback_is_underivable(tmp_path: Path) -> None:
    pkg = write_pkg(
        tmp_path / "p",
        BASE
        + """\
dependencies:
  prompts:
    - id: context/greeting
      version: 1.0.0
      requirement: generate
inputs:
  - name: greeting
    required: false
    default:
      derive: context/greeting
""",
    )
    manifest = cp.validate_package(pkg)
    resolution = cp.resolve_inputs(manifest, {})
    assert resolution.underivable == ["greeting"]
    assert "greeting" not in resolution.values
    with pytest.raises(cp.CannedPromptError, match="unresolved placeholder"):
        cp.render_template("{{ greeting }}", resolution.values)


def test_inline_derive_is_valid(tmp_path: Path) -> None:
    pkg = write_pkg(
        tmp_path / "p",
        BASE
        + """\
inputs:
  - name: greeting
    required: false
    default:
      derive:
        prompt: Produce a greeting suited to the audience.
      value: "(none)"
""",
    )
    manifest = cp.validate_package(pkg)
    assert cp.resolve_inputs(manifest, {}).values["greeting"] == "(none)"


def test_default_with_required_true_fails(tmp_path: Path) -> None:
    pkg = write_pkg(
        tmp_path / "p",
        BASE
        + """\
inputs:
  - name: greeting
    required: true
    default: "hello"
""",
    )
    with pytest.raises(cp.CannedPromptError, match="required: true"):
        cp.validate_package(pkg)


def test_derive_reference_must_be_declared(tmp_path: Path) -> None:
    pkg = write_pkg(
        tmp_path / "p",
        BASE
        + """\
inputs:
  - name: greeting
    required: false
    default:
      derive: context/greeting
""",
    )
    with pytest.raises(cp.CannedPromptError, match="not declared in dependencies"):
        cp.validate_package(pkg)


def test_inline_derive_cannot_also_reference(tmp_path: Path) -> None:
    pkg = write_pkg(
        tmp_path / "p",
        BASE
        + """\
inputs:
  - name: greeting
    required: false
    default:
      derive:
        prompt: Produce a greeting.
        id: context/greeting
""",
    )
    with pytest.raises(cp.CannedPromptError, match="cannot also reference"):
        cp.validate_package(pkg)