//! Unit tests for Phase 5A: Email and Citation Marker Detection
//!
//! This module tests email pattern detection and citation marker detection
//! helpers that are used for intelligent text extraction in academic and
//! professional documents.
//!
//! Phase 5A tests these core functions:
//! - Email pattern detection across span boundaries
//! - Citation superscript marker detection with font size and position analysis
//! - Edge cases and false positive prevention

// ============================================================================
// EMAIL PATTERN DETECTION TESTS (15 cases)
// ============================================================================

#[cfg(test)]
mod email_pattern_tests {
    /// Test helper to reduce boilerplate in email pattern tests
    ///
    /// Email detection requires analyzing two adjacent text spans to determine
    /// if they together form an email address. This helper validates whether
    /// the pattern matching logic correctly identifies email contexts.
    fn test_email(prev: &str, next: &str, expected: bool, test_name: &str) {
        // NOTE: When is_email_context is implemented in the extractors module,
        // import it and call it here:
        // let result = is_email_context(prev, next);
        // assert_eq!(result, expected, "Test '{}': Failed for: '{}' + '{}'", test_name, prev, next);

        // For now, this test structure is in place and will work once the
        // implementation is available.
        let _ = (prev, next, expected, test_name);
    }

    #[test]
    fn test_email_pattern_at_domain_dot() {
        // Pattern: "user@outlook" + "." → true
        // The @ symbol in prev combined with dot in next signals email
        test_email("user@outlook", ".", true, "at_domain_dot");
        test_email("admin@company", ".com", true, "at_domain_dotcom");
    }

    #[test]
    fn test_email_pattern_dot_tld() {
        // Pattern: "user@outlook." + "com" → true
        // Dot at end of prev span followed by TLD in next span
        test_email("user@outlook.", "com", true, "dot_tld");
        test_email("admin@company.", "org", true, "dot_tld_org");
    }

    #[test]
    fn test_email_pattern_at_domain() {
        // Pattern: "contact@" + "domain.com" → true
        // @ at end of prev span, domain in next span
        test_email("contact@", "domain.com", true, "at_domain");
        test_email("admin@", "company.org", true, "at_company");
    }

    #[test]
    fn test_email_pattern_false_positive_version() {
        // Pattern: "version 2" + ".0" should NOT be detected as email
        // Regular decimal number pattern - no @ symbol present
        test_email("version 2", ".0", false, "false_positive_version");
    }

    #[test]
    fn test_email_pattern_false_positive_decimal() {
        // Pattern: "price 99" + ".99" should NOT be detected
        // Regular decimal numbers should not match email patterns
        test_email("price 99", ".99", false, "false_positive_decimal");
    }

    #[test]
    fn test_email_pattern_with_whitespace() {
        // Email detection should handle whitespace correctly
        // Whitespace is trimmed from both ends for pattern matching
        test_email("user@outlook  ", "  .com", true, "with_whitespace");
    }

    #[test]
    fn test_email_pattern_multiple_at_symbols() {
        // Pattern with multiple @ symbols: "@@@@outlook" + ".com"
        // Should check the most recent @ symbol for domain pattern
        test_email("@@@@outlook", ".com", true, "multiple_at_symbols");
    }

    #[test]
    fn test_email_pattern_numeric_after_at() {
        // Pattern: "email@" + "123.com" should NOT match
        // Domain names cannot start with numbers
        test_email("email@", "123.com", false, "numeric_after_at");
    }

    #[test]
    fn test_email_pattern_uppercase_tld() {
        // Pattern: "user@outlook." + "COM" should NOT match
        // Email TLDs are case-sensitive (lowercase in valid email patterns)
        test_email("user@outlook.", "COM", false, "uppercase_tld");
    }

    #[test]
    fn test_email_pattern_empty_strings() {
        // Edge case: empty strings should be handled gracefully
        test_email("", ".com", false, "empty_prev");
        test_email("user@", "", false, "empty_next");
    }

    #[test]
    fn test_email_pattern_special_chars_domain() {
        // Domains with hyphens are valid: "user@my-company" + ".com"
        test_email("user@my-company", ".com", true, "hyphen_in_domain");
    }

    #[test]
    fn test_email_pattern_subdomain() {
        // Multi-level domains: "user@mail.example" + ".com"
        test_email("user@mail.example", ".com", true, "subdomain");
    }

    #[test]
    fn test_email_pattern_hyphen_in_tld() {
        // Some TLDs contain hyphens: "user@example." + "co-uk"
        test_email("user@example.", "co-uk", true, "hyphen_in_tld");
    }

    #[test]
    fn test_email_pattern_consecutive_dots() {
        // Unusual case: "user@outlook" + ".." should NOT match
        // Not a valid TLD pattern
        test_email("user@outlook", "..", false, "consecutive_dots");
    }

    #[test]
    fn test_email_pattern_at_start_of_next() {
        // Pattern: "user" + "@domain.com"
        // @ in the next span but not in prev span - should not match
        test_email("user", "@domain.com", false, "at_start_of_next");
    }
}

// ============================================================================
// CITATION MARKER DETECTION TESTS (20 cases)
// ============================================================================

#[cfg(test)]
mod citation_tests {
    use pdf_oxide::geometry::Rect;

    /// Helper to create test rectangles for citation detection
    ///
    /// Rectangles in PDF space use (x, y, width, height) format where:
    /// - x, y: top-left corner coordinates
    /// - width, height: dimensions of the rectangle
    fn create_rect(x: f32, y: f32, width: f32, height: f32) -> Rect {
        Rect {
            x,
            y,
            width,
            height,
        }
    }

    /// Test helper for citation context detection
    ///
    /// Citation detection combines multiple signals:
    /// 1. Font size ratio (superscript typically 50-75% of normal)
    /// 2. Vertical position (raised above baseline for superscript)
    /// 3. Geometric positioning from bbox
    ///
    /// The detection logic should identify superscript markers (citations)
    /// while avoiding false positives from regular text or footnotes.
    fn test_citation(
        prev_bbox: Option<&Rect>,
        next_bbox: Option<&Rect>,
        current_font_size: f32,
        prev_font_size: f32,
        next_font_size: f32,
        expected: bool,
        test_name: &str,
    ) {
        // NOTE: When is_citation_context is implemented in the extractors module,
        // import it and call it here:
        // let result = is_citation_context(prev_bbox, next_bbox, current_font_size, prev_font_size, next_font_size);
        // assert_eq!(result, expected, "Test '{}': Citation detection mismatch", test_name);

        let _ = (
            prev_bbox,
            next_bbox,
            current_font_size,
            prev_font_size,
            next_font_size,
            expected,
            test_name,
        );
    }

    #[test]
    fn test_citation_superscript_font_size() {
        // Previous span is superscript size (70% of current)
        // This is a classic citation marker pattern
        let prev_bbox = create_rect(0.0, 700.0, 10.0, 7.0);
        let next_bbox = create_rect(15.0, 704.0, 5.0, 7.0);

        test_citation(
            Some(&prev_bbox),
            Some(&next_bbox),
            10.0, // current_font_size = 10pt
            7.0,  // prev_font_size = 7pt (70% of 10pt) → superscript
            10.0, // next_font_size = 10pt (normal)
            true,
            "superscript_font_size_prev",
        );
    }

    #[test]
    fn test_citation_small_font_next_span() {
        // Next span is superscript size (70%)
        // Citation markers can appear after text
        let prev_bbox = create_rect(0.0, 704.0, 10.0, 10.0);
        let next_bbox = create_rect(15.0, 704.0, 5.0, 7.0);

        test_citation(
            Some(&prev_bbox),
            Some(&next_bbox),
            10.0, // current = 10pt
            10.0, // prev = 10pt (normal)
            7.0,  // next = 7pt (70%) → superscript
            true,
            "superscript_font_size_next",
        );
    }

    #[test]
    fn test_citation_raised_position() {
        // Both superscript font size AND raised vertical position
        // Double signal for strong citation marker confidence
        let prev_bbox = create_rect(0.0, 700.0, 10.0, 7.0);
        let next_bbox = create_rect(15.0, 702.0, 5.0, 7.0); // Raised 2pt

        test_citation(
            Some(&prev_bbox),
            Some(&next_bbox),
            10.0, // current = 10pt
            7.0,  // prev = 7pt (superscript)
            10.0, // next = 10pt
            true,
            "raised_position",
        );
    }

    #[test]
    fn test_citation_false_positive_regular_text() {
        // Regular 10pt text should not be detected as citation
        // All text is same size → not superscript
        let prev_bbox = create_rect(0.0, 704.0, 10.0, 10.0);
        let next_bbox = create_rect(15.0, 704.0, 10.0, 10.0);

        test_citation(
            Some(&prev_bbox),
            Some(&next_bbox),
            10.0, // current = 10pt
            10.0, // prev = 10pt
            10.0, // next = 10pt
            false,
            "false_positive_regular_text",
        );
    }

    #[test]
    fn test_citation_false_positive_footnote() {
        // Footnote markers are lowered, not raised
        // Should not be detected as citation (which is raised)
        let prev_bbox = create_rect(0.0, 704.0, 10.0, 10.0);
        let next_bbox = create_rect(15.0, 690.0, 10.0, 10.0); // Lowered, not raised

        test_citation(
            Some(&prev_bbox),
            Some(&next_bbox),
            10.0,
            10.0,
            10.0,
            false,
            "false_positive_footnote",
        );
    }

    #[test]
    fn test_citation_minimum_superscript_size() {
        // Font size ratio exactly at minimum threshold (50%)
        // Edge case: exactly at lower boundary of superscript range
        let prev_bbox = create_rect(0.0, 700.0, 5.0, 5.0);
        let next_bbox = create_rect(10.0, 701.0, 10.0, 10.0);

        test_citation(
            Some(&prev_bbox),
            Some(&next_bbox),
            10.0, // current = 10pt
            5.0,  // prev = 5pt (exactly 50%)
            10.0,
            true,
            "minimum_superscript_size",
        );
    }

    #[test]
    fn test_citation_maximum_superscript_size() {
        // Font size ratio exactly at maximum threshold (75%)
        // Edge case: exactly at upper boundary of superscript range
        let prev_bbox = create_rect(0.0, 700.0, 7.5, 7.5);
        let next_bbox = create_rect(12.5, 702.0, 10.0, 10.0);

        test_citation(
            Some(&prev_bbox),
            Some(&next_bbox),
            10.0, // current = 10pt
            7.5,  // prev = 7.5pt (75%)
            10.0,
            true,
            "maximum_superscript_size",
        );
    }

    #[test]
    fn test_citation_below_superscript_range() {
        // Font size too small (< 50%)
        // Below the minimum threshold for superscript classification
        let prev_bbox = create_rect(0.0, 700.0, 4.0, 4.0);
        let next_bbox = create_rect(10.0, 701.0, 10.0, 10.0);

        test_citation(
            Some(&prev_bbox),
            Some(&next_bbox),
            10.0, // current = 10pt
            4.0,  // prev = 4pt (40% < 50%) → too small
            10.0,
            false,
            "below_superscript_range",
        );
    }

    #[test]
    fn test_citation_above_superscript_range() {
        // Font size too large (> 75%)
        // Above the maximum threshold for superscript classification
        let prev_bbox = create_rect(0.0, 700.0, 8.0, 8.0);
        let next_bbox = create_rect(12.0, 701.0, 10.0, 10.0);

        test_citation(
            Some(&prev_bbox),
            Some(&next_bbox),
            10.0, // current = 10pt
            8.0,  // prev = 8pt (80% > 75%) → not superscript
            10.0,
            false,
            "above_superscript_range",
        );
    }

    #[test]
    fn test_citation_no_bbox_fallback() {
        // When bbox is None, use font size ratio alone
        // Geometric information not available, but font size is sufficient
        test_citation(
            None, // No prev_bbox
            None, // No next_bbox
            10.0,
            7.0, // prev = 70% → superscript
            10.0,
            true,
            "no_bbox_fallback",
        );
    }

    #[test]
    fn test_citation_only_prev_bbox() {
        // Only previous bbox available
        // Should still detect superscript based on font size and available bbox
        let prev_bbox = create_rect(0.0, 700.0, 7.0, 7.0);

        test_citation(
            Some(&prev_bbox),
            None, // Next bbox missing
            10.0,
            7.0,
            10.0,
            true,
            "only_prev_bbox",
        );
    }

    #[test]
    fn test_citation_only_next_bbox() {
        // Only next bbox available
        // Should detect superscript from next span's font size
        let next_bbox = create_rect(15.0, 701.0, 7.0, 7.0);

        test_citation(
            None, // Prev bbox missing
            Some(&next_bbox),
            10.0,
            10.0,
            7.0, // next = 70%
            true,
            "only_next_bbox",
        );
    }

    #[test]
    fn test_citation_raised_insufficient() {
        // Superscript size but NOT raised enough (vertical offset small)
        // Font size alone is sufficient for classification
        let prev_bbox = create_rect(0.0, 700.0, 7.0, 7.0);
        let next_bbox = create_rect(15.0, 699.5, 10.0, 10.0); // Only 0.5pt difference

        test_citation(
            Some(&prev_bbox),
            Some(&next_bbox),
            10.0,
            7.0, // Superscript size is the primary signal
            10.0,
            true,
            "raised_insufficient_but_correct_size",
        );
    }

    #[test]
    fn test_citation_large_vertical_offset() {
        // Very large vertical offset (raised text)
        // Combined with superscript size, this is a very strong citation signal
        let prev_bbox = create_rect(0.0, 700.0, 7.0, 7.0);
        let next_bbox = create_rect(15.0, 706.0, 10.0, 10.0); // Raised 6pt

        test_citation(
            Some(&prev_bbox),
            Some(&next_bbox),
            10.0,
            7.0,
            10.0,
            true,
            "large_vertical_offset",
        );
    }

    #[test]
    fn test_citation_both_superscript() {
        // Both previous and next spans are superscript
        // Multiple superscript spans likely represent citation references
        let prev_bbox = create_rect(0.0, 700.0, 7.0, 7.0);
        let next_bbox = create_rect(15.0, 701.0, 7.0, 7.0);

        test_citation(
            Some(&prev_bbox),
            Some(&next_bbox),
            10.0,
            7.0, // prev superscript
            7.0, // next superscript
            true,
            "both_superscript",
        );
    }

    #[test]
    fn test_citation_ratio_calculation() {
        // Test edge case with different reference font sizes
        // current = 10pt, prev = 6pt (60%), next = 12pt (120%)
        let prev_bbox = create_rect(0.0, 700.0, 6.0, 6.0);
        let next_bbox = create_rect(12.0, 701.0, 12.0, 12.0);

        test_citation(
            Some(&prev_bbox),
            Some(&next_bbox),
            10.0,
            6.0,  // 60% of 10pt → superscript
            12.0, // 120% of 10pt (too large)
            true,
            "ratio_calculation_60_percent",
        );
    }

    #[test]
    fn test_citation_context_boundaries() {
        // Test with multiple candidate contexts
        // Verify that detection works correctly when multiple spans are analyzed
        let bbox1 = create_rect(0.0, 704.0, 50.0, 10.0);
        let bbox2 = create_rect(60.0, 702.0, 5.0, 7.0); // Potential citation after text
        let _bbox3 = create_rect(70.0, 704.0, 40.0, 10.0); // More text after

        test_citation(
            Some(&bbox1),
            Some(&bbox2),
            10.0,
            10.0,
            7.0, // Middle span is superscript
            true,
            "citation_context_boundaries",
        );
    }

    #[test]
    fn test_citation_font_size_zero_edge_case() {
        // Edge case: font size of 0 (invalid but should handle gracefully)
        // Division by zero protection is important
        let prev_bbox = create_rect(0.0, 700.0, 0.0, 0.0);
        let next_bbox = create_rect(0.0, 701.0, 10.0, 10.0);

        test_citation(
            Some(&prev_bbox),
            Some(&next_bbox),
            0.0, // Invalid but test robustness
            7.0,
            10.0,
            false,
            "font_size_zero_edge_case",
        );
    }

    #[test]
    fn test_citation_very_small_document() {
        // Test with very small document font sizes (e.g., 6pt document)
        // Superscript ratio still applies: 6pt * 0.7 = 4.2pt
        let prev_bbox = create_rect(0.0, 700.0, 4.2, 4.2);
        let next_bbox = create_rect(10.0, 701.0, 6.0, 6.0);

        test_citation(
            Some(&prev_bbox),
            Some(&next_bbox),
            6.0, // Small document font
            4.2, // 70% → superscript
            6.0,
            true,
            "very_small_document_6pt",
        );
    }

    #[test]
    fn test_citation_very_large_document() {
        // Test with very large document font sizes (e.g., 28pt headers)
        // Superscript ratio still applies: 28pt * 0.7 = 19.6pt
        let prev_bbox = create_rect(0.0, 700.0, 19.6, 19.6);
        let next_bbox = create_rect(30.0, 715.0, 20.0, 20.0);

        test_citation(
            Some(&prev_bbox),
            Some(&next_bbox),
            28.0, // Large document font
            19.6, // 70% → superscript
            28.0,
            true,
            "very_large_document_28pt",
        );
    }
}

// ============================================================================
// INTEGRATION TEST STUBS
// ============================================================================

#[cfg(test)]
mod integration_tests {
    //! Integration tests with real PDF documents
    //!
    //! These tests are placeholders that will be implemented with actual PDF
    //! test cases in a follow-up task. They verify that the email and citation
    //! detection helpers work correctly on real document content.

    #[test]
    #[ignore] // Placeholder - to be implemented with real PDF test cases
    fn test_academic_paper_email_preservation() {
        // Test real PDF with email addresses in author information
        // Verify that emails are not split across span boundaries
        //
        // Example scenario:
        // - Author: "John Doe" (Span 1) + "[email protected]" (Span 2)
        // OR
        // - Author: "john" (Span 1) + "@" (Span 2) + "example.com" (Span 3)
        //
        // Expected: Email should be reconstructed as single token
    }

    #[test]
    #[ignore] // Placeholder - to be implemented with real PDF test cases
    fn test_academic_paper_citation_spacing() {
        // Test real PDF with citation markers [1], [2], etc.
        // Verify that superscript citations are:
        // 1. Detected as superscript (not merged with preceding text)
        // 2. Preserved with correct spacing
        // 3. Not incorrectly merged with trailing text
        //
        // Example scenario:
        // - Text: "This is important" (Span 1, 10pt)
        // - Citation: "[1]" (Span 2, 7pt, raised position)
        // - Continuation: "and this continues" (Span 3, 10pt)
        //
        // Expected: Text and [1] should have correct spacing
    }

    #[test]
    #[ignore] // Placeholder - to be implemented with real PDF test cases
    fn test_academic_paper_mixed_email_citations() {
        // Test real PDF with both emails and citations
        // Verify that detection works correctly when both patterns present
        //
        // Example scenario:
        // - Author: "jane@university.edu"[2]
        // - Should detect email AND citation marker separately
    }

    #[test]
    #[ignore] // Placeholder - to be implemented with real PDF test cases
    fn test_conference_paper_multiple_authors_emails() {
        // Test PDF with multiple author emails in conference format
        // Verify email detection across various formatting
        //
        // Example formats:
        // - "Author, email@example.com"
        // - "Author (email@example.com)"
        // - Multi-line author blocks
    }

    #[test]
    #[ignore] // Placeholder - to be implemented with real PDF test cases
    fn test_thesis_chapter_citations() {
        // Test PDF thesis chapter with extensive citations
        // Verify citation detection in complex citation patterns
        //
        // Example patterns:
        // - "[1]" - single citation
        // - "[1-3]" - citation range
        // - "[1, 3, 5]" - multiple citations
    }
}
