import pytest
import tempfile
import os
import json
from pr.core.usage_tracker import UsageTracker

@pytest.fixture
def temp_usage_file(tmp_path, monkeypatch):
    from pr.core import usage_tracker
    original_file = usage_tracker.USAGE_DB_FILE
    temp_file = str(tmp_path / "usage.json")
    monkeypatch.setattr(usage_tracker, 'USAGE_DB_FILE', temp_file)
    yield temp_file
    if os.path.exists(temp_file):
        os.remove(temp_file)
    monkeypatch.setattr(usage_tracker, 'USAGE_DB_FILE', original_file)

def test_usage_tracker_init():
    tracker = UsageTracker()
    summary = tracker.get_session_summary()
    assert summary['requests'] == 0
    assert summary['total_tokens'] == 0
    assert summary['estimated_cost'] == 0.0

def test_track_request_known_model():
    tracker = UsageTracker()
    tracker.track_request('gpt-3.5-turbo', 100, 50)
    
    summary = tracker.get_session_summary()
    assert summary['requests'] == 1
    assert summary['input_tokens'] == 100
    assert summary['output_tokens'] == 50
    assert summary['total_tokens'] == 150
    assert 'gpt-3.5-turbo' in summary['models_used']
    # Cost: (100/1000)*0.0005 + (50/1000)*0.0015 = 0.00005 + 0.000075 = 0.000125
    assert abs(summary['estimated_cost'] - 0.000125) < 1e-6

def test_track_request_unknown_model():
    tracker = UsageTracker()
    tracker.track_request('unknown-model', 100, 50)
    
    summary = tracker.get_session_summary()
    assert summary['requests'] == 1
    assert summary['estimated_cost'] == 0.0  # Unknown model, cost 0

def test_track_request_multiple():
    tracker = UsageTracker()
    tracker.track_request('gpt-3.5-turbo', 100, 50)
    tracker.track_request('gpt-4', 200, 100)
    
    summary = tracker.get_session_summary()
    assert summary['requests'] == 2
    assert summary['input_tokens'] == 300
    assert summary['output_tokens'] == 150
    assert summary['total_tokens'] == 450
    assert len(summary['models_used']) == 2

def test_get_formatted_summary():
    tracker = UsageTracker()
    tracker.track_request('gpt-3.5-turbo', 100, 50)
    
    formatted = tracker.get_formatted_summary()
    assert "Total Requests: 1" in formatted
    assert "Total Tokens: 150" in formatted
    assert "Estimated Cost: $0.0001" in formatted
    assert "gpt-3.5-turbo" in formatted

def test_get_total_usage_no_file(temp_usage_file):
    total = UsageTracker.get_total_usage()
    assert total['total_requests'] == 0
    assert total['total_tokens'] == 0
    assert total['total_cost'] == 0.0

def test_get_total_usage_with_data(temp_usage_file):
    # Manually create history file
    history = [
        {'timestamp': '2023-01-01', 'model': 'gpt-3.5-turbo', 'input_tokens': 100, 'output_tokens': 50, 'total_tokens': 150, 'cost': 0.000125},
        {'timestamp': '2023-01-02', 'model': 'gpt-4', 'input_tokens': 200, 'output_tokens': 100, 'total_tokens': 300, 'cost': 0.008}
    ]
    with open(temp_usage_file, 'w') as f:
        json.dump(history, f)
    
    total = UsageTracker.get_total_usage()
    assert total['total_requests'] == 2
    assert total['total_tokens'] == 450
    assert abs(total['total_cost'] - 0.008125) < 1e-6