from __future__ import annotations

import json
from pathlib import Path

import pytest

from pdf2md.math_render import MathJaxCommandResult, MathJaxRenderChecker
from pdf2md.quality import MathCheckerUnavailable, MathExpression


def test_mathjax_checker_batches_expressions_as_json(tmp_path: Path) -> None:
    helper = make_helper(tmp_path)
    calls = []

    def runner(command: tuple[str, ...], stdin: str, timeout_seconds: int) -> MathJaxCommandResult:
        calls.append((command, json.loads(stdin), timeout_seconds))
        return MathJaxCommandResult(
            command,
            0,
            stdout=json.dumps(
                {
                    "results": [
                        {"index": 0, "ok": True},
                        {"index": 1, "ok": False, "message": "Undefined control sequence"},
                    ]
                }
            ),
        )

    checker = MathJaxRenderChecker(
        helper_path=helper,
        which=lambda executable: "C:/node/node.exe" if executable == "node" else None,
        runner=runner,
        timeout_seconds=7,
    )
    expressions = (
        MathExpression(0, "x_i^2", False, (0, 7)),
        MathExpression(1, "\\bad", True, (9, 18)),
    )

    results = checker.check_expressions(expressions)

    assert [result.ok for result in results] == [True, False]
    assert results[1].message == "Undefined control sequence"
    assert calls == [
        (
            ("C:/node/node.exe", str(helper)),
            {
                "expressions": [
                    {"index": 0, "body": "x_i^2", "display": False},
                    {"index": 1, "body": "\\bad", "display": True},
                ]
            },
            7,
        )
    ]


def test_mathjax_checker_reports_missing_node_as_unavailable(tmp_path: Path) -> None:
    checker = MathJaxRenderChecker(helper_path=make_helper(tmp_path), which=lambda _: None)

    with pytest.raises(MathCheckerUnavailable, match="Node.js"):
        checker.check_expressions((MathExpression(0, "x", False, (0, 3)),))


def test_mathjax_checker_reports_helper_failure_as_unavailable(tmp_path: Path) -> None:
    helper = make_helper(tmp_path)

    def runner(command: tuple[str, ...], stdin: str, timeout_seconds: int) -> MathJaxCommandResult:
        return MathJaxCommandResult(command, 124, stderr="MathJax helper timed out")

    checker = MathJaxRenderChecker(
        helper_path=helper,
        which=lambda _: "node",
        runner=runner,
    )

    with pytest.raises(MathCheckerUnavailable, match="timed out"):
        checker.check_expressions((MathExpression(0, "x", False, (0, 3)),))


def test_mathjax_checker_reports_invalid_json_as_unavailable(tmp_path: Path) -> None:
    helper = make_helper(tmp_path)

    def runner(command: tuple[str, ...], stdin: str, timeout_seconds: int) -> MathJaxCommandResult:
        return MathJaxCommandResult(command, 0, stdout="not json")

    checker = MathJaxRenderChecker(
        helper_path=helper,
        which=lambda _: "node",
        runner=runner,
    )

    with pytest.raises(MathCheckerUnavailable, match="invalid JSON"):
        checker.check_expressions((MathExpression(0, "x", False, (0, 3)),))


def test_mathjax_checker_rejects_mismatched_result_indexes(tmp_path: Path) -> None:
    helper = make_helper(tmp_path)

    def runner(command: tuple[str, ...], stdin: str, timeout_seconds: int) -> MathJaxCommandResult:
        return MathJaxCommandResult(command, 0, stdout=json.dumps({"results": [{"index": 99, "ok": True}]}))

    checker = MathJaxRenderChecker(
        helper_path=helper,
        which=lambda _: "node",
        runner=runner,
    )

    with pytest.raises(MathCheckerUnavailable, match="indexes"):
        checker.check_expressions((MathExpression(0, "x", False, (0, 3)),))


def make_helper(tmp_path: Path) -> Path:
    helper = tmp_path / "check.mjs"
    helper.write_text("// fake helper", encoding="utf-8")
    return helper