#![allow(warnings)]
//! Tests for ISO 32000-1:2008 Section 14.7.4.4 Parent Tree Lookup
//!
//! The parent tree provides a reverse mapping from marked content IDs (MCIDs)
//! to the structure elements that own them. This enables efficient lookup of
//! structural information for any marked content on a page.
//!
//! PDF spec defines parent tree usage:
//! 1. Maps each MCID to its parent structure element
//! 2. Enables structure-based text grouping
//! 3. Supports accessibility and reflow operations

use pdf_oxide::structure::types::{ParentTree, ParentTreeEntry, StructElem, StructType};

/// Mock structure for testing parent tree lookups
#[derive(Clone, Debug)]
struct MCIDMapping {
    page: u32,
    mcid: u32,
    parent_struct_type: String,
}

#[test]
fn test_parent_tree_single_mcid_lookup() {
    // Parent tree should map MCID to its parent structure element
    let mut parent_tree = ParentTree::new();

    let mut page_map = std::collections::HashMap::new();
    let parent_elem = StructElem::new(StructType::P);
    page_map.insert(0, ParentTreeEntry::StructElem(Box::new(parent_elem)));

    parent_tree.page_mappings.insert(0, page_map);

    // Should find the parent for MCID 0 on page 0
    let result = parent_tree.get_parent(0, 0);
    assert!(result.is_some(), "Parent tree should find MCID 0 on page 0");
}

#[test]
fn test_parent_tree_missing_mcid() {
    // Parent tree should return None for non-existent MCID
    let parent_tree = ParentTree::new();

    let result = parent_tree.get_parent(0, 0);
    assert!(result.is_none(), "Parent tree should return None for missing MCID");
}

#[test]
fn test_parent_tree_multiple_mcids_same_page() {
    // Parent tree should support multiple MCIDs on same page
    let mut parent_tree = ParentTree::new();
    let mut page_map = std::collections::HashMap::new();

    // Add three MCIDs to same page
    for mcid in 0..3 {
        let parent_elem = StructElem::new(StructType::P);
        page_map.insert(mcid, ParentTreeEntry::StructElem(Box::new(parent_elem)));
    }

    parent_tree.page_mappings.insert(0, page_map);

    // All three should be found
    assert!(parent_tree.get_parent(0, 0).is_some());
    assert!(parent_tree.get_parent(0, 1).is_some());
    assert!(parent_tree.get_parent(0, 2).is_some());

    // Non-existent MCID should not be found
    assert!(parent_tree.get_parent(0, 3).is_none());
}

#[test]
fn test_parent_tree_multiple_pages() {
    // Parent tree should support MCIDs on different pages
    let mut parent_tree = ParentTree::new();

    // Page 0: MCID 0
    let mut page0_map = std::collections::HashMap::new();
    page0_map.insert(0, ParentTreeEntry::StructElem(Box::new(StructElem::new(StructType::P))));
    parent_tree.page_mappings.insert(0, page0_map);

    // Page 1: MCID 0 (different element)
    let mut page1_map = std::collections::HashMap::new();
    page1_map.insert(0, ParentTreeEntry::StructElem(Box::new(StructElem::new(StructType::H1))));
    parent_tree.page_mappings.insert(1, page1_map);

    // Same MCID on different pages should return different parents
    assert!(parent_tree.get_parent(0, 0).is_some());
    assert!(parent_tree.get_parent(1, 0).is_some());

    // MCID that doesn't exist on page should not be found
    assert!(parent_tree.get_parent(0, 1).is_none());
    assert!(parent_tree.get_parent(1, 1).is_none());
}

#[test]
fn test_parent_tree_page_independence() {
    // MCIDs are page-specific and should not cross pages
    let mut parent_tree = ParentTree::new();

    // Page 0: MCIDs 0, 1, 2
    let mut page0_map = std::collections::HashMap::new();
    for mcid in 0..3 {
        page0_map
            .insert(mcid, ParentTreeEntry::StructElem(Box::new(StructElem::new(StructType::P))));
    }
    parent_tree.page_mappings.insert(0, page0_map);

    // Page 1: MCIDs 0, 1 (different content)
    let mut page1_map = std::collections::HashMap::new();
    for mcid in 0..2 {
        page1_map
            .insert(mcid, ParentTreeEntry::StructElem(Box::new(StructElem::new(StructType::H1))));
    }
    parent_tree.page_mappings.insert(1, page1_map);

    // Page 0 should have 3 MCIDs, page 1 should have 2
    assert!(parent_tree.get_parent(0, 2).is_some());
    assert!(parent_tree.get_parent(1, 2).is_none());

    assert!(parent_tree.get_parent(0, 0).is_some());
    assert!(parent_tree.get_parent(1, 0).is_some());
}

#[test]
fn test_parent_tree_struct_type_preservation() {
    // Parent tree should preserve structure type of parent elements
    let mut parent_tree = ParentTree::new();
    let mut page_map = std::collections::HashMap::new();

    // Create parent element with specific struct type
    let parent_elem = StructElem::new(StructType::H2);
    page_map.insert(0, ParentTreeEntry::StructElem(Box::new(parent_elem)));
    parent_tree.page_mappings.insert(0, page_map);

    // Parent should be retrievable
    let parent = parent_tree.get_parent(0, 0);
    assert!(parent.is_some());

    // If we could unwrap and check the type, it should be H2
    if let Some(ParentTreeEntry::StructElem(elem)) = parent {
        assert_eq!(elem.struct_type, StructType::H2);
    }
}

#[test]
fn test_parent_tree_nested_parents() {
    // Nested structure: Document > Section > Paragraph with multiple MCIDs
    let mut parent_tree = ParentTree::new();
    let mut page_map = std::collections::HashMap::new();

    // Simulate a document structure:
    // Document (MCID 0-2 are child content)
    //   └─ Section
    //       └─ Paragraph (MCID 0, 1, 2)

    for mcid in 0..3 {
        page_map
            .insert(mcid, ParentTreeEntry::StructElem(Box::new(StructElem::new(StructType::P))));
    }
    parent_tree.page_mappings.insert(0, page_map);

    // All MCIDs 0-2 should be found with Paragraph as immediate parent
    for mcid in 0..3 {
        let parent = parent_tree.get_parent(0, mcid);
        assert!(parent.is_some());
        if let Some(ParentTreeEntry::StructElem(elem)) = parent {
            assert_eq!(elem.struct_type, StructType::P);
        }
    }
}

#[test]
fn test_parent_tree_object_references() {
    // Parent tree should support indirect object references (not resolved yet)
    let mut parent_tree = ParentTree::new();
    let mut page_map = std::collections::HashMap::new();

    // Add object reference entry (indirect reference)
    page_map.insert(0, ParentTreeEntry::ObjectRef(42, 0)); // Object 42, generation 0
    parent_tree.page_mappings.insert(0, page_map);

    // Should still be retrievable (though not fully resolved)
    let entry = parent_tree.get_parent(0, 0);
    assert!(entry.is_some());

    if let Some(ParentTreeEntry::ObjectRef(obj_num, gen)) = entry {
        assert_eq!(*obj_num, 42);
        assert_eq!(*gen, 0);
    }
}

#[test]
fn test_parent_tree_mixed_entries() {
    // Parent tree can mix direct and indirect references
    let mut parent_tree = ParentTree::new();
    let mut page_map = std::collections::HashMap::new();

    // MCID 0: Direct reference
    page_map.insert(0, ParentTreeEntry::StructElem(Box::new(StructElem::new(StructType::P))));

    // MCID 1: Indirect reference
    page_map.insert(1, ParentTreeEntry::ObjectRef(99, 0));

    parent_tree.page_mappings.insert(0, page_map);

    // Both should be retrievable
    assert!(parent_tree.get_parent(0, 0).is_some());
    assert!(parent_tree.get_parent(0, 1).is_some());
}

#[test]
fn test_parent_tree_structure_element_hierarchy() {
    // Parent tree entry should preserve full structure element information
    let mut parent_tree = ParentTree::new();
    let mut page_map = std::collections::HashMap::new();

    let mut parent_elem = StructElem::new(StructType::H1);
    parent_elem.page = Some(0);

    page_map.insert(0, ParentTreeEntry::StructElem(Box::new(parent_elem)));
    parent_tree.page_mappings.insert(0, page_map);

    let entry = parent_tree.get_parent(0, 0);
    if let Some(ParentTreeEntry::StructElem(elem)) = entry {
        assert_eq!(elem.struct_type, StructType::H1);
        assert_eq!(elem.page, Some(0));
    }
}

#[test]
fn test_parent_tree_empty_structure_element() {
    // Parent tree should handle empty structure elements
    let mut parent_tree = ParentTree::new();
    let mut page_map = std::collections::HashMap::new();

    // Empty element (no children)
    let empty_elem = StructElem::new(StructType::Div);
    page_map.insert(0, ParentTreeEntry::StructElem(Box::new(empty_elem)));

    parent_tree.page_mappings.insert(0, page_map);

    let entry = parent_tree.get_parent(0, 0);
    assert!(entry.is_some());
}

#[test]
fn test_parent_tree_bulk_lookup_performance() {
    // Test that parent tree lookup is efficient for many MCIDs
    let mut parent_tree = ParentTree::new();
    let mut page_map = std::collections::HashMap::new();

    // Create 1000 MCIDs
    for mcid in 0..1000 {
        page_map
            .insert(mcid, ParentTreeEntry::StructElem(Box::new(StructElem::new(StructType::P))));
    }
    parent_tree.page_mappings.insert(0, page_map);

    // Lookups should succeed for all MCIDs
    for mcid in 0..1000 {
        assert!(parent_tree.get_parent(0, mcid).is_some());
    }

    // Non-existent MCIDs should still return None
    assert!(parent_tree.get_parent(0, 1000).is_none());
}

#[test]
fn test_parent_tree_mcid_zero() {
    // MCID 0 should be valid and retrievable
    let mut parent_tree = ParentTree::new();
    let mut page_map = std::collections::HashMap::new();

    page_map.insert(0, ParentTreeEntry::StructElem(Box::new(StructElem::new(StructType::P))));
    parent_tree.page_mappings.insert(0, page_map);

    let entry = parent_tree.get_parent(0, 0);
    assert!(entry.is_some(), "MCID 0 should be valid");
}

#[test]
fn test_parent_tree_high_mcid_values() {
    // Parent tree should support high MCID values
    let mut parent_tree = ParentTree::new();
    let mut page_map = std::collections::HashMap::new();

    let high_mcid = 999999;
    page_map
        .insert(high_mcid, ParentTreeEntry::StructElem(Box::new(StructElem::new(StructType::P))));
    parent_tree.page_mappings.insert(0, page_map);

    assert!(parent_tree.get_parent(0, high_mcid).is_some());
}

#[test]
fn test_parent_tree_specification_reference() {
    // This test documents the spec sections that define parent tree
    // ISO 32000-1:2008 Section 14.7.4.4: Parent Tree
    //
    // Key requirements:
    // 1. Maps MCID values to structure elements
    // 2. Enables reverse lookup from content to structure
    // 3. Supports both direct and indirect references
    // 4. Page-specific MCID numbering

    let spec_requirements = [
        "Maps MCID to structure element",
        "Enables reverse structure lookup",
        "Supports direct and indirect refs",
        "Page-specific MCID numbering",
    ];

    assert_eq!(spec_requirements.len(), 4);
    assert_eq!(spec_requirements[0], "Maps MCID to structure element");
}

#[test]
fn test_parent_tree_lookup_different_struct_types() {
    // Same MCID can have different parent types on different pages
    let mut parent_tree = ParentTree::new();

    // Page 0: MCID 0 parent is Paragraph
    let mut page0_map = std::collections::HashMap::new();
    page0_map.insert(0, ParentTreeEntry::StructElem(Box::new(StructElem::new(StructType::P))));
    parent_tree.page_mappings.insert(0, page0_map);

    // Page 1: MCID 0 parent is Heading
    let mut page1_map = std::collections::HashMap::new();
    page1_map.insert(0, ParentTreeEntry::StructElem(Box::new(StructElem::new(StructType::H1))));
    parent_tree.page_mappings.insert(1, page1_map);

    // Check that parent types are correctly distinguished by page
    if let Some(ParentTreeEntry::StructElem(p0)) = parent_tree.get_parent(0, 0) {
        assert_eq!(p0.struct_type, StructType::P);
    }

    if let Some(ParentTreeEntry::StructElem(p1)) = parent_tree.get_parent(1, 0) {
        assert_eq!(p1.struct_type, StructType::H1);
    }
}
