#!/usr/bin/env python3
"""
Tests for GET /api/habits endpoint.
Validates API response structure, status codes, and error handling.
"""

import json
import urllib.request
import urllib.error
from pathlib import Path
from datetime import datetime

# API endpoint - assumes server is running on localhost:8088
API_BASE = 'http://localhost:8088'
HABITS_FILE = Path(__file__).parent / 'habits.json'


def test_habits_endpoint_exists():
    """Test that GET /api/habits endpoint exists and returns 200."""
    print("Testing endpoint exists and returns 200...")
    
    try:
        response = urllib.request.urlopen(f'{API_BASE}/api/habits', timeout=5)
        status_code = response.getcode()
        
        assert status_code == 200, f"Expected status 200, got {status_code}"
        print("✓ Endpoint returns 200 status")
    except urllib.error.HTTPError as e:
        raise AssertionError(f"Endpoint returned HTTP {e.code}: {e.reason}")
    except urllib.error.URLError as e:
        raise AssertionError(f"Could not connect to API server: {e.reason}")


def test_habits_response_is_json():
    """Test that response is valid JSON."""
    print("Testing response is valid JSON...")
    
    try:
        response = urllib.request.urlopen(f'{API_BASE}/api/habits', timeout=5)
        content = response.read().decode('utf-8')
        
        try:
            data = json.loads(content)
            print("✓ Response is valid JSON")
            return data
        except json.JSONDecodeError as e:
            raise AssertionError(f"Response is not valid JSON: {e}")
    except urllib.error.URLError as e:
        raise AssertionError(f"Could not connect to API server: {e.reason}")


def test_habits_response_structure():
    """Test that response has correct structure: habits array and lastUpdated."""
    print("Testing response structure...")
    
    data = test_habits_response_is_json()
    
    # Check for habits array
    assert 'habits' in data, "Response missing 'habits' field"
    assert isinstance(data['habits'], list), "'habits' field must be an array"
    print("✓ Response contains 'habits' array")
    
    # Check for lastUpdated timestamp
    assert 'lastUpdated' in data, "Response missing 'lastUpdated' field"
    print("✓ Response contains 'lastUpdated' field")


def test_habits_lastupdated_is_iso():
    """Test that lastUpdated is a valid ISO timestamp."""
    print("Testing lastUpdated is valid ISO timestamp...")
    
    data = test_habits_response_is_json()
    last_updated = data.get('lastUpdated')
    
    assert last_updated, "lastUpdated field is empty"
    
    try:
        # Try to parse as ISO datetime
        dt = datetime.fromisoformat(last_updated.replace('Z', '+00:00'))
        print(f"✓ lastUpdated is valid ISO timestamp: {last_updated}")
    except (ValueError, AttributeError) as e:
        raise AssertionError(f"lastUpdated is not a valid ISO timestamp: {e}")


def test_empty_habits_returns_empty_array():
    """Test that empty habits.json returns empty array, not error."""
    print("Testing empty habits file returns empty array...")
    
    # Backup original file
    backup = None
    if HABITS_FILE.exists():
        backup = HABITS_FILE.read_text()
    
    try:
        # Write empty habits file
        HABITS_FILE.write_text(json.dumps({
            'lastUpdated': datetime.now().isoformat(),
            'habits': []
        }))
        
        # Request habits
        response = urllib.request.urlopen(f'{API_BASE}/api/habits', timeout=5)
        data = json.loads(response.read().decode('utf-8'))
        
        assert data['habits'] == [], "Empty habits.json should return empty array"
        print("✓ Empty habits.json returns empty array (not error)")
        
    finally:
        # Restore backup
        if backup:
            HABITS_FILE.write_text(backup)


def test_habits_with_data():
    """Test that habits with data are returned correctly."""
    print("Testing habits with data are returned...")
    
    # Backup original file
    backup = None
    if HABITS_FILE.exists():
        backup = HABITS_FILE.read_text()
    
    try:
        # Write test habits
        test_data = {
            'lastUpdated': '2026-02-10T10:00:00.000Z',
            'habits': [
                {
                    'id': 'test-habit-1',
                    'name': 'Bazin',
                    'frequency': 'daily',
                    'createdAt': '2026-02-10T10:00:00.000Z',
                    'completions': ['2026-02-10T10:00:00.000Z']
                }
            ]
        }
        HABITS_FILE.write_text(json.dumps(test_data, indent=2))
        
        # Request habits
        response = urllib.request.urlopen(f'{API_BASE}/api/habits', timeout=5)
        data = json.loads(response.read().decode('utf-8'))
        
        assert len(data['habits']) == 1, "Should return 1 habit"
        habit = data['habits'][0]
        assert habit['name'] == 'Bazin', f"Expected habit name 'Bazin', got '{habit['name']}'"
        assert habit['frequency'] == 'daily', f"Expected frequency 'daily', got '{habit['frequency']}'"
        print("✓ Habits with data are returned correctly")
        
    finally:
        # Restore backup
        if backup:
            HABITS_FILE.write_text(backup)


def run_all_tests():
    """Run all tests and report results."""
    print("=" * 60)
    print("Running GET /api/habits endpoint tests")
    print("=" * 60)
    print()
    
    tests = [
        test_habits_endpoint_exists,
        test_habits_response_is_json,
        test_habits_response_structure,
        test_habits_lastupdated_is_iso,
        test_empty_habits_returns_empty_array,
        test_habits_with_data,
    ]
    
    passed = 0
    failed = 0
    
    for test in tests:
        try:
            test()
            passed += 1
            print()
        except AssertionError as e:
            print(f"✗ FAILED: {e}")
            print()
            failed += 1
        except Exception as e:
            print(f"✗ ERROR: {e}")
            print()
            failed += 1
    
    print("=" * 60)
    print(f"Results: {passed} passed, {failed} failed")
    print("=" * 60)
    
    return failed == 0


if __name__ == '__main__':
    import sys
    
    # Check if API server is running
    try:
        urllib.request.urlopen(f'{API_BASE}/api/status', timeout=2)
    except urllib.error.URLError:
        print("ERROR: API server is not running on localhost:8088")
        print("Start the server with: python3 dashboard/api.py")
        sys.exit(1)
    
    success = run_all_tests()
    sys.exit(0 if success else 1)