"""Tests for the ground-truth dataset loader."""
from __future__ import annotations

import json
import os
import tempfile

import pytest

from prometheus.domain.entities import GroundTruthExample
from prometheus.infrastructure.dataset_loader import FileDatasetLoader


@pytest.fixture
def loader():
    return FileDatasetLoader()


class TestCsvLoader:
    def test_load_csv(self, loader, tmp_path):
        csv_file = tmp_path / "test.csv"
        csv_file.write_text("input,expected_output\nhello,world\nfoo,bar\n")
        result = loader.load(str(csv_file))
        assert len(result) == 2
        assert result[0].input_text == "hello"
        assert result[0].expected_output == "world"
        assert result[1].input_text == "foo"
        assert result[1].expected_output == "bar"

    def test_load_csv_skips_empty_input(self, loader, tmp_path):
        csv_file = tmp_path / "test.csv"
        csv_file.write_text("input,expected_output\n,bar\nhello,world\n")
        result = loader.load(str(csv_file))
        assert len(result) == 1
        assert result[0].input_text == "hello"

    def test_load_csv_with_whitespace(self, loader, tmp_path):
        csv_file = tmp_path / "test.csv"
        csv_file.write_text("input,expected_output\n  hello  ,  world  \n")
        result = loader.load(str(csv_file))
        assert result[0].input_text == "hello"
        assert result[0].expected_output == "world"

    def test_load_csv_empty_file(self, loader, tmp_path):
        csv_file = tmp_path / "test.csv"
        csv_file.write_text("input,expected_output\n")
        result = loader.load(str(csv_file))
        assert len(result) == 0


class TestJsonLoader:
    def test_load_json(self, loader, tmp_path):
        json_file = tmp_path / "test.json"
        data = [
            {"input": "hello", "expected_output": "world"},
            {"input": "foo", "expected_output": "bar"},
        ]
        json_file.write_text(json.dumps(data))
        result = loader.load(str(json_file))
        assert len(result) == 2
        assert result[0].input_text == "hello"
        assert result[0].expected_output == "world"

    def test_load_json_skips_empty_input(self, loader, tmp_path):
        json_file = tmp_path / "test.json"
        data = [
            {"input": "", "expected_output": "bar"},
            {"input": "hello", "expected_output": "world"},
        ]
        json_file.write_text(json.dumps(data))
        result = loader.load(str(json_file))
        assert len(result) == 1

    def test_load_json_not_array_raises(self, loader, tmp_path):
        json_file = tmp_path / "test.json"
        json_file.write_text(json.dumps({"not": "an array"}))
        with pytest.raises(ValueError, match="must be an array"):
            loader.load(str(json_file))


class TestUnsupportedFormat:
    def test_unsupported_extension_raises(self, loader, tmp_path):
        txt_file = tmp_path / "test.txt"
        txt_file.write_text("hello")
        with pytest.raises(ValueError, match="Unsupported dataset format"):
            loader.load(str(txt_file))