import pytest
from backend.services.video_service import VideoService
from backend.core.exceptions import ValidationError, UnsupportedFormatError, ErrorCode


class TestVideoService:
    
    @pytest.fixture
    def video_service(self):
        return VideoService()
    
    def test_extract_video_id_standard_url(self, video_service):
        """Test extraction from standard YouTube watch URLs."""
        test_cases = [
            ("https://youtube.com/watch?v=dQw4w9WgXcQ", "dQw4w9WgXcQ"),
            ("https://www.youtube.com/watch?v=dQw4w9WgXcQ", "dQw4w9WgXcQ"),
            ("http://youtube.com/watch?v=dQw4w9WgXcQ", "dQw4w9WgXcQ"),
            ("youtube.com/watch?v=dQw4w9WgXcQ", "dQw4w9WgXcQ"),
            ("https://youtube.com/watch?v=dQw4w9WgXcQ&t=30s", "dQw4w9WgXcQ"),
            ("https://youtube.com/watch?v=dQw4w9WgXcQ&feature=share", "dQw4w9WgXcQ"),
        ]
        
        for url, expected_id in test_cases:
            result = video_service.extract_video_id(url)
            assert result == expected_id, f"Failed for URL: {url}"
    
    def test_extract_video_id_short_url(self, video_service):
        """Test extraction from youtu.be short URLs."""
        test_cases = [
            ("https://youtu.be/dQw4w9WgXcQ", "dQw4w9WgXcQ"),
            ("http://youtu.be/dQw4w9WgXcQ", "dQw4w9WgXcQ"),
            ("youtu.be/dQw4w9WgXcQ", "dQw4w9WgXcQ"),
            ("https://youtu.be/dQw4w9WgXcQ?t=30", "dQw4w9WgXcQ"),
        ]
        
        for url, expected_id in test_cases:
            result = video_service.extract_video_id(url)
            assert result == expected_id, f"Failed for URL: {url}"
    
    def test_extract_video_id_embed_url(self, video_service):
        """Test extraction from embed URLs."""
        test_cases = [
            ("https://youtube.com/embed/dQw4w9WgXcQ", "dQw4w9WgXcQ"),
            ("https://www.youtube.com/embed/dQw4w9WgXcQ", "dQw4w9WgXcQ"),
            ("http://youtube.com/embed/dQw4w9WgXcQ", "dQw4w9WgXcQ"),
            ("youtube.com/embed/dQw4w9WgXcQ", "dQw4w9WgXcQ"),
        ]
        
        for url, expected_id in test_cases:
            result = video_service.extract_video_id(url)
            assert result == expected_id, f"Failed for URL: {url}"
    
    def test_extract_video_id_mobile_url(self, video_service):
        """Test extraction from mobile YouTube URLs."""
        test_cases = [
            ("https://m.youtube.com/watch?v=dQw4w9WgXcQ", "dQw4w9WgXcQ"),
            ("http://m.youtube.com/watch?v=dQw4w9WgXcQ", "dQw4w9WgXcQ"),
            ("m.youtube.com/watch?v=dQw4w9WgXcQ", "dQw4w9WgXcQ"),
        ]
        
        for url, expected_id in test_cases:
            result = video_service.extract_video_id(url)
            assert result == expected_id, f"Failed for URL: {url}"
    
    def test_extract_video_id_invalid_url(self, video_service):
        """Test that invalid URLs raise ValidationError."""
        invalid_urls = [
            "https://vimeo.com/123456789",
            "https://dailymotion.com/video/x123456",
            "not-a-url-at-all",
            "https://example.com",
            "https://youtube.com/",
            "https://youtube.com/channel/UCxxxxx",
        ]
        
        for url in invalid_urls:
            with pytest.raises(ValidationError) as exc_info:
                video_service.extract_video_id(url)
            assert exc_info.value.error_code == ErrorCode.INVALID_URL
    
    def test_extract_video_id_invalid_video_id_length(self, video_service):
        """Test that video IDs with incorrect length are rejected."""
        invalid_urls = [
            "https://youtube.com/watch?v=short",  # Too short
            "https://youtube.com/watch?v=thisistoolong123",  # Too long
            "https://youtu.be/abc",  # Too short
        ]
        
        for url in invalid_urls:
            with pytest.raises(ValidationError) as exc_info:
                video_service.extract_video_id(url)
            assert exc_info.value.error_code == ErrorCode.INVALID_URL
    
    def test_extract_video_id_playlist_url(self, video_service):
        """Test that playlist URLs raise UnsupportedFormatError."""
        playlist_urls = [
            "https://youtube.com/playlist?list=PLrAXtmErZgOeiKm4sgNOknGvNjby9efdf",
            "https://www.youtube.com/watch?v=dQw4w9WgXcQ&list=PLrAXtmErZgOeiKm4sgNOknGvNjby9efdf",
            "https://youtube.com/watch?v=dQw4w9WgXcQ&list=PLxxxxx&index=2",
        ]
        
        for url in playlist_urls:
            with pytest.raises(UnsupportedFormatError) as exc_info:
                video_service.extract_video_id(url)
            assert exc_info.value.error_code == ErrorCode.UNSUPPORTED_FORMAT
            assert "playlist" in exc_info.value.message.lower()
    
    def test_extract_video_id_empty_url(self, video_service):
        """Test that empty URL raises ValidationError."""
        with pytest.raises(ValidationError) as exc_info:
            video_service.extract_video_id("")
        assert exc_info.value.error_code == ErrorCode.INVALID_URL
        assert "empty" in exc_info.value.message.lower()
        
        with pytest.raises(ValidationError) as exc_info:
            video_service.extract_video_id(None)
        assert exc_info.value.error_code == ErrorCode.INVALID_URL
    
    def test_validate_video_id(self, video_service):
        """Test video ID validation logic."""
        # Valid IDs
        valid_ids = [
            "dQw4w9WgXcQ",
            "aB3-567_890",
            "___________",  # All underscores
            "-----------",  # All hyphens
            "ABCDEFGHIJK",  # All uppercase
            "abcdefghijk",  # All lowercase
            "12345678901",  # All numbers
        ]
        
        for video_id in valid_ids:
            assert video_service._validate_video_id(video_id) is True
        
        # Invalid IDs
        invalid_ids = [
            "short",  # Too short
            "thisistoolong",  # Too long
            "has space11",  # Contains space
            "has@special",  # Contains special char
            "",  # Empty
            None,  # None
        ]
        
        for video_id in invalid_ids:
            assert video_service._validate_video_id(video_id) is False
    
    def test_normalize_url(self, video_service):
        """Test URL normalization."""
        video_id = "dQw4w9WgXcQ"
        expected = "https://youtube.com/watch?v=dQw4w9WgXcQ"
        assert video_service.normalize_url(video_id) == expected
    
    def test_get_supported_formats(self, video_service):
        """Test getting supported formats list."""
        formats = video_service.get_supported_formats()
        assert isinstance(formats, list)
        assert len(formats) > 0
        assert all("VIDEO_ID" in fmt for fmt in formats)