"""Phase-2 config and external prompt pack (docs/phase-2 P1a, sections 14-15).

``config.py`` centralizes every phase-2 path/env read (no hard-coded data
paths - section 15). ``prompt.py`` loads the EXTERNAL, versioned prompt pack
(section 14): prompts never live in this repo; the pack carries its own
version and each prompt has an individual content hash, so ``prompt_version``
can enter the response-cache composite key (D6). The minimal pack under
``tests/fixtures/prompt_pack/`` is the local fixture so CI never depends on
the external prompt repository, and missing/invalid packs raise a clear
``PromptPackError`` instead of falling back silently.
"""

from __future__ import annotations

from pathlib import Path

import pytest

from pf1e_simulator.config import (
    ENV_LLM_API_KEY,
    ENV_PROMPT_PACK_DIR,
    env_path,
    env_str,
    llm_api_key,
)
from pf1e_simulator.prompt import (
    PromptPack,
    PromptPackError,
    clear_pack_cache,
    load_prompt_pack,
)

FIXTURE_PACK = Path(__file__).resolve().parent / "fixtures" / "prompt_pack"
_FIXTURE_VERSION = "0.1.0-test"
_FIXTURE_PROMPT_NAME = "nl_default"


def _write_pack(root: Path, *, version: str, prompts: dict[str, str]) -> None:
    """Write a minimal prompt pack directory (version.txt + <name>.md)."""
    root.mkdir(parents=True, exist_ok=True)
    (root / "version.txt").write_text(version, encoding="utf-8")
    for name, text in prompts.items():
        (root / f"{name}.md").write_text(text, encoding="utf-8")


# ── config.py ──────────────────────────────────────────────────────────────


def test_env_str_and_path_round_trip(
    monkeypatch: pytest.MonkeyPatch,
    tmp_path: Path,
) -> None:
    """env_str/env_path read the environment and respect deletes."""
    monkeypatch.setenv("PF1E_SIM_TEST_STR", "abc")
    monkeypatch.setenv("PF1E_SIM_TEST_PATH", str(tmp_path / "x"))
    assert env_str("PF1E_SIM_TEST_STR") == "abc"
    assert env_str("PF1E_SIM_TEST_UNSET") is None
    assert env_str("PF1E_SIM_TEST_UNSET", default="d") == "d"
    assert env_path("PF1E_SIM_TEST_PATH") == tmp_path / "x"
    assert env_path("PF1E_SIM_TEST_UNSET") is None
    monkeypatch.delenv("PF1E_SIM_TEST_STR")
    assert env_str("PF1E_SIM_TEST_STR") is None


def test_llm_api_key_reads_env(monkeypatch: pytest.MonkeyPatch) -> None:
    """llm_api_key surfaces the dedicated env var (None when unset)."""
    assert llm_api_key() is None
    monkeypatch.setenv(ENV_LLM_API_KEY, "sk-test")
    assert llm_api_key() == "sk-test"


# ── prompt.py — loading and validation ─────────────────────────────────────


def test_load_fixture_pack() -> None:
    """The local fixture loads: version pinned, prompts readable by name."""
    pack = load_prompt_pack(FIXTURE_PACK)
    assert pack.version == _FIXTURE_VERSION
    assert pack.root == FIXTURE_PACK
    text = pack.get(_FIXTURE_PROMPT_NAME)
    assert "tactical director" in text
    # The pack has exactly the fixture prompts (only <name>.md files count).
    assert pack.get("nl_default") == (FIXTURE_PACK / "nl_default.md").read_text(
        encoding="utf-8"
    )


def test_prompt_version_stable_and_content_sensitive(tmp_path: Path) -> None:
    """prompt_version carries pack version + per-prompt content hash (D6)."""
    pack = load_prompt_pack(FIXTURE_PACK)
    a = pack.prompt_version(_FIXTURE_PROMPT_NAME)
    b = pack.prompt_version(_FIXTURE_PROMPT_NAME)
    assert a == b  # deterministic within a loaded pack
    assert a.startswith(f"{_FIXTURE_VERSION}:{_FIXTURE_PROMPT_NAME}:")

    other = tmp_path / "other"
    _write_pack(other, version=_FIXTURE_VERSION, prompts={_FIXTURE_PROMPT_NAME: "x"})
    assert load_prompt_pack(other).prompt_version(_FIXTURE_PROMPT_NAME) != a

    bumped = tmp_path / "bumped"
    _write_pack(bumped, version="1.0.0", prompts={_FIXTURE_PROMPT_NAME: "x"})
    assert load_prompt_pack(bumped).prompt_version(_FIXTURE_PROMPT_NAME).startswith(
        "1.0.0:"
    )


def test_missing_prompt_raises_clear_error(tmp_path: Path) -> None:
    """A missing prompt name fails loudly, naming the expected file."""
    other = tmp_path / "other"
    _write_pack(other, version="1.0.0", prompts={"other": "x"})
    with pytest.raises(PromptPackError, match=r"missing.*nl_default\.md"):
        load_prompt_pack(other).get("nl_default")


def test_missing_pack_dir_raises(tmp_path: Path) -> None:
    """A nonexistent pack path is a clear error, not a silent fallback."""
    with pytest.raises(PromptPackError, match="not found"):
        load_prompt_pack(tmp_path / "nope")


def test_missing_version_file_raises(tmp_path: Path) -> None:
    """A pack without version.txt is invalid (traceability, section 14)."""
    root = tmp_path / "noversion"
    _write_pack(root, version="", prompts={})
    (root / "version.txt").unlink()
    with pytest.raises(PromptPackError, match="version\\.txt"):
        load_prompt_pack(root)


def test_empty_version_file_raises(tmp_path: Path) -> None:
    """An empty version.txt is invalid (no untraceable pack)."""
    root = tmp_path / "emptyversion"
    _write_pack(root, version="", prompts={_FIXTURE_PROMPT_NAME: "x"})
    with pytest.raises(PromptPackError, match="empty"):
        load_prompt_pack(root)


def test_unset_pack_dir_raises(
    monkeypatch: pytest.MonkeyPatch,
) -> None:
    """Without PF1E_PROMPT_PACK_DIR, loading raises instead of falling back."""
    monkeypatch.delenv(ENV_PROMPT_PACK_DIR, raising=False)
    with pytest.raises(PromptPackError, match=ENV_PROMPT_PACK_DIR):
        load_prompt_pack()


def test_pack_dir_from_env(
    monkeypatch: pytest.MonkeyPatch,
) -> None:
    """load_prompt_pack() resolves the pack through the env var (section 15)."""
    monkeypatch.setenv(ENV_PROMPT_PACK_DIR, str(FIXTURE_PACK))
    assert load_prompt_pack().version == _FIXTURE_VERSION
    monkeypatch.delenv(ENV_PROMPT_PACK_DIR)


def test_cache_and_clear(tmp_path: Path) -> None:
    """Repeated loads share the cached instance; clear_pack_cache drops it."""
    root = tmp_path / "cached"
    _write_pack(root, version="1.0.0", prompts={_FIXTURE_PROMPT_NAME: "x"})
    first = load_prompt_pack(root)
    assert load_prompt_pack(root) is first
    clear_pack_cache()
    assert load_prompt_pack(root) is not first


def test_load_returns_prompt_pack_instance() -> None:
    """The loaded object is a PromptPack (typed API for the client layer)."""
    pack = load_prompt_pack(FIXTURE_PACK)
    assert isinstance(pack, PromptPack)
    assert pack.version == _FIXTURE_VERSION