import json
import os
from pathlib import Path
import pytest

from src.report_generation import main

# Fixtures
def sample_analysis_results():
    return [
        {"run_id": 21, "metric_name": "cluster_variance", "value": 0.12, "cluster_score": 0.94},
        {"run_id": 22, "metric_name": "cluster_variance", "value": 0.10, "cluster_score": 0.97},
        {"run_id": 23, "metric_name": "cluster_variance", "value": 0.11, "cluster_score": 0.95}
    ]

@pytest.fixture
def analysis_results_file(tmp_path):
    data = sample_analysis_results()
    input_path = tmp_path / "analysis_results.json"
    with open(input_path, "w", encoding="utf-8") as f:
        json.dump(data, f)
    return input_path

@pytest.fixture
def output_file_path(tmp_path):
    return tmp_path / "report_summary.json"

# Tests
def test_generate_report_creates_file(tmp_path, monkeypatch):
    results = sample_analysis_results()
    report_path = main.generate_report(results)
    assert isinstance(report_path, str)
    path_obj = Path(report_path)
    assert path_obj.exists()
    with open(path_obj, 'r', encoding='utf-8') as f:
        data = json.load(f)
    assert 'summary' in data
    assert 'average_cluster_score' in data['summary']
    assert data['summary']['total_runs'] == 3


def test_generate_report_invalid_input():
    with pytest.raises((TypeError, AssertionError)):
        main.generate_report(None)


def test_generate_report_correct_json_structure(tmp_path):
    results = sample_analysis_results()
    report_path = main.generate_report(results)
    with open(report_path, 'r', encoding='utf-8') as f:
        data = json.load(f)
    assert isinstance(data, dict)
    summary = data.get('summary', {})
    assert isinstance(summary.get('average_cluster_score'), (float, int))
    assert summary.get('total_runs') == len(results)


def test_generate_report_ci_validation(monkeypatch):
    # CI check: ensure deterministic filename generation and structure
    results = sample_analysis_results()
    report_path = main.generate_report(results)
    second_path = main.generate_report(results)
    assert Path(report_path).exists()
    assert Path(second_path).exists()
    assert report_path != ""
    # The output should be a JSON file with summary content
    assert report_path.endswith('.json')