"""
Input Validation Security Tests

Tests that verify user inputs are properly validated and sanitized
across all application entry points.
"""

import pytest
from tests.test_utils import add_src_to_path

add_src_to_path()


class TestResearchQueryValidation:
    """Test validation of research query inputs."""

    def test_query_length_validation(self):
        """Test that overly long queries are rejected or truncated."""
        # Very long query (potential DoS or buffer overflow)
        extremely_long_query = "test query " * 10000  # ~100KB

        # Should validate query length
        # Either reject with error or truncate to reasonable length

        # Maximum reasonable query length: 1000-10000 characters
        max_length = 10000
        assert len(extremely_long_query) > max_length  # Test is valid

        # Implementation should check:
        # if len(query) > max_length:
        #     raise ValueError("Query too long")
        # or:
        #     query = query[:max_length]

        pass  # Implementation-specific

    def test_query_special_characters_handling(self):
        """Test that special characters in queries are handled safely."""
        special_char_queries = [
            "test\0query",  # Null byte
            "test\nquery",  # Newline
            "test\r\nquery",  # CRLF
            "test\tquery",  # Tab
            "test\\query",  # Backslash
            "test'query",  # Single quote
            'test"query',  # Double quote
            "test`query",  # Backtick
            "test;query",  # Semicolon
            "test|query",  # Pipe
            "test<query>",  # Angle brackets
        ]

        for query in special_char_queries:
            # Should handle special characters safely
            # Either escape, sanitize, or reject
            assert isinstance(query, str)

    def test_unicode_handling(self):
        """Test that Unicode and international characters are handled correctly."""
        unicode_queries = [
            "研究查询",  # Chinese
            "Исследование",  # Russian
            "بحث",  # Arabic (RTL text)
            "🔬📚🧪",  # Emojis
            "café ñoño",  # Accented characters
            "Σ∑∫",  # Mathematical symbols
        ]

        for query in unicode_queries:
            # Should properly handle Unicode
            # UTF-8 encoding, no corruption
            assert isinstance(query, str)
            # Verify encoding/decoding works
            encoded = query.encode("utf-8")
            decoded = encoded.decode("utf-8")
            assert decoded == query

    def test_empty_and_whitespace_queries(self):
        """Test handling of empty and whitespace-only queries."""
        empty_queries = [
            "",  # Empty string
            " ",  # Single space
            "   ",  # Multiple spaces
            "\n",  # Just newline
            "\t\n  ",  # Mixed whitespace
            None,  # Null
        ]

        for query in empty_queries:
            # Should reject empty queries or handle gracefully
            # return meaningful error message

            if query is None:
                # None should be rejected or converted to empty string
                pass
            else:
                # Whitespace-only queries should be rejected
                stripped = query.strip() if query else ""
                if not stripped:
                    # Should reject
                    pass

    def test_path_traversal_in_query(self):
        """Test that path traversal attempts in queries are sanitized."""
        path_traversal_queries = [
            "../../../etc/passwd",
            "..\\..\\..\\windows\\system32",
            "....//....//....//etc/passwd",
            "%2e%2e%2f%2e%2e%2fetc/passwd",  # URL encoded
            "test/../../../etc/passwd",
        ]

        for query in path_traversal_queries:
            # Query itself is fine (just a search string)
            # But should never be used directly in file system operations
            # If saving query to file, sanitize filename

            # Sanitization example:
            import re

            sanitized = re.sub(r"[./\\]", "", query)
            # Should not contain path separators
            assert "../" not in sanitized

    def test_command_injection_in_query(self):
        """Test that command injection attempts are prevented."""
        command_injection_queries = [
            "test; ls -la",
            "test | cat /etc/passwd",
            "test && rm -rf /",
            "test $(whoami)",
            "test `whoami`",
            "test; DROP TABLE users;--",
        ]

        for query in command_injection_queries:
            # Query string itself is safe (just text)
            # But must NEVER be passed to shell commands

            # NEVER do:
            # os.system(f"search {query}")  # Dangerous!

            # Safe approaches:
            # - Use query as data only (database queries, API calls)
            # - Never concatenate into shell commands
            # - If shell needed, use subprocess with args list

            assert True  # Query string is safe as data


class TestURLInputValidation:
    """Test validation of URL inputs."""

    def test_url_scheme_validation(self):
        """Test that only allowed URL schemes are accepted."""
        allowed_schemes = ["http", "https"]
        dangerous_schemes = [
            "file:///etc/passwd",
            "javascript:alert('XSS')",
            "data:text/html,<script>alert('XSS')</script>",
            "ftp://example.com",
            "gopher://example.com",
        ]

        from urllib.parse import urlparse

        for url in dangerous_schemes:
            parsed = urlparse(url)
            scheme = parsed.scheme.lower()

            # Should reject non-HTTP(S) schemes
            assert scheme not in allowed_schemes

    def test_internal_url_blocking(self):
        """Test that internal/private URLs are blocked (SSRF prevention)."""
        # DevSkim: ignore DS137138 - Intentionally using insecure URLs for testing SSRF prevention
        internal_urls = [
            "http://localhost/admin",
            "http://127.0.0.1/",
            "http://[::1]/",  # IPv6 localhost
            "http://169.254.169.254/latest/meta-data/",  # AWS metadata
            "http://192.168.1.1/",  # Private network
            "http://10.0.0.1/",  # Private network
            "http://172.16.0.1/",  # Private network
        ]

        for url in internal_urls:
            # Should block internal URLs when fetching external content
            # Use URL whitelist or IP address validation
            from urllib.parse import urlparse

            parsed = urlparse(url)
            hostname = parsed.hostname

            # Check if IP is internal
            if hostname:
                import ipaddress

                try:
                    ip = ipaddress.ip_address(hostname)
                    # Should block private/local IPs
                    is_private = (
                        ip.is_private
                        or ip.is_loopback
                        or ip.is_link_local
                        or ip.is_reserved
                    )
                    if is_private:
                        # Should reject
                        pass
                except ValueError:
                    # Not an IP address, might be hostname
                    # Check for localhost, local domains
                    if hostname.lower() in ["localhost", "127.0.0.1", "::1"]:
                        # Should reject
                        pass

    @pytest.mark.skip(reason="documentation/placeholder test - not implemented")
    def test_url_redirect_handling(self):
        """Test that URL redirects are handled safely."""
        # URL redirects can be used for SSRF attacks:
        # 1. Attacker provides public URL
        # 2. Public URL redirects to internal URL
        # 3. Server follows redirect to internal resource

        # Mitigation:
        # - Validate final destination after redirects
        # - Limit number of redirects
        # - Check each redirect hop against blacklist

        pass  # Implementation-specific


class TestFileUploadValidation:
    """Test file upload security (if applicable)."""

    def test_file_type_validation(self):
        """Test that file types are validated."""
        # If LDR accepts file uploads:
        # - Validate file extension (whitelist)
        # - Validate MIME type
        # - Validate file content (magic bytes)

        allowed_extensions = [".txt", ".pdf", ".md"]
        dangerous_extensions = [
            ".exe",
            ".sh",
            ".bat",
            ".php",
            ".jsp",
            ".aspx",
        ]

        # Should reject dangerous file types
        for ext in dangerous_extensions:
            # Implementation should check:
            # if file_extension not in allowed_extensions:
            #     raise ValueError("File type not allowed")
            assert ext not in allowed_extensions

    def test_file_size_limits(self):
        """Test that file size is limited."""
        # File size limits prevent:
        # - DoS via large uploads
        # - Disk space exhaustion
        # - Memory exhaustion

        max_file_size = 10 * 1024 * 1024  # 10 MB example

        # Implementation should check:
        # if file_size > max_file_size:
        #     raise ValueError("File too large")

        assert max_file_size > 0

    def test_filename_sanitization(self):
        """Test that filenames are sanitized."""
        dangerous_filenames = [
            "../../../etc/passwd",  # Path traversal
            "test.php.jpg",  # Double extension
            "file\0.txt",  # Null byte injection
            "CON.txt",  # Windows reserved name
            "<script>.txt",  # HTML injection
        ]

        import re

        for filename in dangerous_filenames:
            # Sanitize filename
            # Remove path separators, special characters
            sanitized = re.sub(r"[^a-zA-Z0-9._-]", "_", filename)
            sanitized = sanitized.replace("..", "")

            # Sanitized filename should be safe
            assert ".." not in sanitized
            assert "/" not in sanitized
            assert "\\" not in sanitized


class TestDatabaseInputValidation:
    """Test validation for database-bound inputs."""

    def test_id_format_validation(self):
        """Test that ID parameters are validated."""
        # IDs should be validated to expected format
        # Prevents SQL injection and other attacks

        valid_id_patterns = [
            r"^[a-zA-Z0-9-_]{1,100}$",  # Alphanumeric with hyphens
            r"^\d+$",  # Numeric only
            r"^[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}$",  # UUID
        ]

        malicious_ids = [
            "1' OR '1'='1",  # SQL injection
            "../admin",  # Path traversal
            "<script>alert('xss')</script>",  # XSS
            "$(rm -rf /)",  # Command injection
        ]

        import re

        for pattern in valid_id_patterns:
            for mal_id in malicious_ids:
                # Malicious IDs should not match valid patterns
                assert not re.match(pattern, mal_id)

    def test_integer_bounds_validation(self):
        """Test that integer inputs are within valid bounds."""
        # Integer overflow/underflow prevention
        import sys

        test_values = [
            -1,  # Negative (if not allowed)
            0,  # Zero (might be invalid)
            sys.maxsize,  # Maximum int
            sys.maxsize + 1,  # Overflow
            -sys.maxsize - 1,  # Minimum int
        ]

        # Validate integers are within expected range
        min_value = 0
        max_value = 1000000

        for value in test_values:
            if value < min_value or value > max_value:
                # Should reject out-of-bounds values
                pass


class TestSecurityInputValidationDocumentation:
    """Documentation tests for input validation strategy."""

    @pytest.mark.skip(reason="documentation/placeholder test - not implemented")
    def test_input_validation_principles(self):
        """
        Document input validation best practices.

        Defense in Depth - Input Validation Layers:
        1. Client-side validation (UX, not security)
        2. API layer validation (format, type, length)
        3. Business logic validation (rules, constraints)
        4. Database layer validation (constraints, types)

        Input Validation Strategies:
        1. Whitelist > Blacklist
           - Define what is allowed (whitelist)
           - Reject everything else
           - Don't try to block specific patterns (blacklist)

        2. Validate Early
           - Validate at entry point
           - Fail fast with clear errors
           - Don't process invalid data

        3. Sanitize vs Reject
           - Sanitize: Clean/escape dangerous content
           - Reject: Refuse invalid input entirely
           - Prefer reject for security-critical inputs

        4. Context-Specific Validation
           - SQL context: Use parameterized queries
           - HTML context: Use escaping
           - Shell context: Use argument arrays
           - URL context: Use URL parsing/validation

        LDR Input Validation Areas:
        1. Research queries (text)
        2. URLs for fetching content
        3. User authentication credentials
        4. API parameters (research_id, settings)
        5. File paths (if file operations exist)

        Validation Checklist:
        - [ ] Length limits enforced
        - [ ] Type checking (string, int, bool)
        - [ ] Format validation (regex patterns)
        - [ ] Range validation (min/max)
        - [ ] Encoding validation (UTF-8)
        - [ ] Injection prevention (SQL, XSS, command)
        - [ ] Path traversal prevention
        - [ ] SSRF prevention (URL validation)
        """
        assert True  # Documentation test

    @pytest.mark.skip(reason="documentation/placeholder test - not implemented")
    def test_common_validation_mistakes(self):
        """
        Document common input validation mistakes to avoid.

        Common Mistakes:
        1. Validating after using the input
           - ✗ process(user_input); validate(user_input)
           - ✓ validate(user_input); process(user_input)

        2. Client-side validation only
           - ✗ JavaScript validation without server check
           - ✓ Validate on both client and server

        3. Blacklist instead of whitelist
           - ✗ if input contains "script": reject
           - ✓ if input matches "[a-z0-9]": accept

        4. Inconsistent validation
           - ✗ Different rules in different endpoints
           - ✓ Centralized validation functions

        5. Trusting "safe" sources
           - ✗ Database values are safe (stored XSS!)
           - ✓ Validate/escape all external data

        6. Insufficient error handling
           - ✗ Silent failures, continue processing
           - ✓ Explicit errors, stop processing

        7. Double encoding issues
           - URL encode, then HTML encode, etc.
           - Different contexts need different encoding
        """
        assert True  # Documentation test


def test_comprehensive_input_validation():
    """
    Comprehensive test documenting all input validation requirements.

    Input Types and Validation:

    1. Text Inputs (research queries, usernames, etc.):
       - Length: 1-10000 characters
       - Encoding: UTF-8
       - Special chars: Allowed but escaped for output
       - Whitespace: Trimmed
       - Empty: Rejected

    2. URLs:
       - Scheme: http/https only
       - No internal IPs (SSRF prevention)
       - Length limit: 2000 characters
       - Validation: url parse + IP check

    3. IDs (research_id, user_id):
       - Format: UUID or alphanumeric
       - Length: Fixed or max 100 chars
       - Special chars: Not allowed
       - SQL injection: Prevented by ORM

    4. Integers (page numbers, limits, counts):
       - Range: 0-1000000
       - Type: Python int
       - Overflow: Checked

    5. Booleans (flags, settings):
       - Values: true/false, 1/0
       - Type: Python bool
       - Validation: Strict type checking

    6. JSON Payloads:
       - Schema validation
       - Required fields check
       - Type checking
       - Size limit: 1MB

    7. File Uploads (if applicable):
       - Type whitelist
       - Size limit: 10MB
       - Filename sanitization
       - Content validation

    All validation should:
    - Happen before processing
    - Provide clear error messages
    - Log validation failures
    - Never expose sensitive info in errors
    """
    assert True  # Documentation test
