//! Core Data Structures for API Reference Generation
//!
//! This module contains all the data structures used by the API reference generator,
//! including trait information, type definitions, code examples, and interactive
//! documentation components.

use crate::api_generator_config::{GeneratorConfig, PlaygroundConfig};
use crate::error::{Result, SklearsError};
use serde::{Deserialize, Serialize};
use std::collections::HashMap;
use std::time::Duration;

// ================================================================================================
// CORE API REFERENCE STRUCTURES
// ================================================================================================

/// Complete API reference for a crate
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct ApiReference {
    /// Name of the crate
    pub crate_name: String,
    /// Version of the crate
    pub version: String,
    /// Analyzed traits
    pub traits: Vec<TraitInfo>,
    /// Extracted type information
    pub types: Vec<TypeInfo>,
    /// Code examples
    pub examples: Vec<CodeExample>,
    /// Cross-references between API elements
    pub cross_references: HashMap<String, Vec<String>>,
    /// Generation metadata
    pub metadata: ApiMetadata,
}

impl ApiReference {
    /// Convert to JSON representation
    pub fn to_json(&self) -> Result<String> {
        serde_json::to_string_pretty(self)
            .map_err(|e| SklearsError::InvalidInput(format!("JSON serialization failed: {}", e)))
    }

    /// Convert to HTML representation
    pub fn to_html(&self) -> Result<String> {
        let mut html = String::new();
        html.push_str(&format!(
            "<html><head><title>API Reference - {}</title></head><body>",
            self.crate_name
        ));
        html.push_str(&format!("<h1>API Reference for {}</h1>", self.crate_name));

        // Traits section
        if !self.traits.is_empty() {
            html.push_str("<h2>Traits</h2>");
            for trait_info in &self.traits {
                html.push_str(&format!("<h3>{}</h3>", trait_info.name));
                html.push_str(&format!("<p>{}</p>", trait_info.description));

                if !trait_info.methods.is_empty() {
                    html.push_str("<h4>Methods</h4><ul>");
                    for method in &trait_info.methods {
                        html.push_str(&format!(
                            "<li><code>{}</code> - {}</li>",
                            method.signature, method.description
                        ));
                    }
                    html.push_str("</ul>");
                }
            }
        }

        // Types section
        if !self.types.is_empty() {
            html.push_str("<h2>Types</h2>");
            for type_info in &self.types {
                html.push_str(&format!("<h3>{}</h3>", type_info.name));
                html.push_str(&format!("<p>{}</p>", type_info.description));
            }
        }

        // Examples section
        if !self.examples.is_empty() {
            html.push_str("<h2>Examples</h2>");
            for example in &self.examples {
                html.push_str(&format!("<h3>{}</h3>", example.title));
                html.push_str(&format!("<p>{}</p>", example.description));
                html.push_str(&format!(
                    "<pre><code class=\"{}\">{}</code></pre>",
                    example.language, example.code
                ));
            }
        }

        html.push_str("</body></html>");
        Ok(html)
    }

    /// Convert to Markdown representation
    pub fn to_markdown(&self) -> Result<String> {
        let mut md = String::new();
        md.push_str(&format!("# API Reference - {}\n\n", self.crate_name));
        md.push_str(&format!("Version: {}\n\n", self.version));

        // Traits section
        if !self.traits.is_empty() {
            md.push_str("## Traits\n\n");
            for trait_info in &self.traits {
                md.push_str(&format!("### {}\n\n", trait_info.name));
                md.push_str(&format!("{}\n\n", trait_info.description));

                if !trait_info.methods.is_empty() {
                    md.push_str("#### Methods\n\n");
                    for method in &trait_info.methods {
                        md.push_str(&format!(
                            "- `{}` - {}\n",
                            method.signature, method.description
                        ));
                    }
                    md.push('\n');
                }
            }
        }

        // Types section
        if !self.types.is_empty() {
            md.push_str("## Types\n\n");
            for type_info in &self.types {
                md.push_str(&format!("### {}\n\n", type_info.name));
                md.push_str(&format!("{}\n\n", type_info.description));
            }
        }

        // Examples section
        if !self.examples.is_empty() {
            md.push_str("## Examples\n\n");
            for example in &self.examples {
                md.push_str(&format!("### {}\n\n", example.title));
                md.push_str(&format!("{}\n\n", example.description));
                md.push_str(&format!(
                    "```{}\n{}\n```\n\n",
                    example.language, example.code
                ));
            }
        }

        Ok(md)
    }

    /// Generate interactive playground HTML
    pub fn to_interactive(&self) -> Result<String> {
        let mut html = String::new();
        html.push_str("<!DOCTYPE html><html><head>");
        html.push_str("<title>Interactive API Reference</title>");
        html.push_str(
            "<script src=\"https://unpkg.com/@webassembly/wasi-sdk@0.11.0/bin/wasm-ld\"></script>",
        );
        html.push_str("</head><body>");
        html.push_str(&format!(
            "<h1>Interactive Reference - {}</h1>",
            self.crate_name
        ));
        html.push_str("<div id=\"playground\">");
        html.push_str("<textarea id=\"code-editor\" rows=\"20\" cols=\"80\">");

        // Add a sample example
        if let Some(example) = self.examples.first() {
            html.push_str(&example.code);
        } else {
            html.push_str(
                "// Write your code here\nfn main() {\n    println!(\"Hello, sklears!\");\n}",
            );
        }

        html.push_str("</textarea>");
        html.push_str("<br><button onclick=\"runCode()\">Run Code</button>");
        html.push_str("<div id=\"output\"></div>");
        html.push_str("</div>");
        html.push_str("<script>");
        html.push_str("function runCode() {");
        html.push_str("  const code = document.getElementById('code-editor').value;");
        html.push_str(
            "  document.getElementById('output').innerHTML = 'Code execution would happen here';",
        );
        html.push('}');
        html.push_str("</script>");
        html.push_str("</body></html>");

        Ok(html)
    }
}

/// Information about a crate
#[derive(Debug, Clone)]
#[allow(dead_code)]
pub struct CrateInfo {
    pub name: String,
    pub version: String,
    pub description: String,
    pub modules: Vec<String>,
    pub dependencies: Vec<String>,
}

/// Metadata about the API reference generation
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct ApiMetadata {
    /// When the reference was generated
    pub generation_time: String,
    /// Version of the generator tool
    pub generator_version: String,
    /// Version of the crate being documented
    pub crate_version: String,
    /// Rust version used
    pub rust_version: String,
    /// Configuration used for generation
    pub config: GeneratorConfig,
}

impl Default for ApiMetadata {
    fn default() -> Self {
        Self {
            generation_time: chrono::Utc::now().to_string(),
            generator_version: env!("CARGO_PKG_VERSION").to_string(),
            crate_version: "unknown".to_string(),
            rust_version: env!("CARGO_PKG_RUST_VERSION").to_string(),
            config: GeneratorConfig::default(),
        }
    }
}

// ================================================================================================
// TRAIT-RELATED STRUCTURES
// ================================================================================================

/// Information about a trait
#[derive(Debug, Clone, Serialize, Deserialize, Default)]
pub struct TraitInfo {
    /// Name of the trait
    pub name: String,
    /// Documentation description
    pub description: String,
    /// Full path to the trait
    pub path: String,
    /// Generic parameters
    pub generics: Vec<String>,
    /// Associated types
    pub associated_types: Vec<AssociatedType>,
    /// Methods defined in the trait
    pub methods: Vec<MethodInfo>,
    /// Supertraits (traits this trait extends)
    pub supertraits: Vec<String>,
    /// Implementations found
    pub implementations: Vec<String>,
}

/// Information about an associated type
#[derive(Debug, Clone, Serialize, Deserialize, Default)]
pub struct AssociatedType {
    /// Name of the associated type
    pub name: String,
    /// Documentation for the associated type
    pub description: String,
    /// Bounds on the associated type
    pub bounds: Vec<String>,
}

/// Information about a method
#[derive(Debug, Clone, Serialize, Deserialize, Default)]
pub struct MethodInfo {
    /// Name of the method
    pub name: String,
    /// Full signature of the method
    pub signature: String,
    /// Documentation description
    pub description: String,
    /// Parameters of the method
    pub parameters: Vec<ParameterInfo>,
    /// Return type
    pub return_type: String,
    /// Whether the method is required or has a default implementation
    pub required: bool,
}

/// Information about a method parameter
#[derive(Debug, Clone, Serialize, Deserialize, Default)]
pub struct ParameterInfo {
    /// Name of the parameter
    pub name: String,
    /// Type of the parameter
    pub param_type: String,
    /// Documentation for the parameter
    pub description: String,
    /// Whether the parameter is optional
    pub optional: bool,
}

// ================================================================================================
// TYPE-RELATED STRUCTURES
// ================================================================================================

/// Information about a type
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct TypeInfo {
    /// Name of the type
    pub name: String,
    /// Documentation description
    pub description: String,
    /// Full path to the type
    pub path: String,
    /// Kind of type (struct, enum, union, etc.)
    pub kind: TypeKind,
    /// Generic parameters
    pub generics: Vec<String>,
    /// Fields (for structs) or variants (for enums)
    pub fields: Vec<FieldInfo>,
    /// Trait implementations
    pub trait_impls: Vec<String>,
}

/// Kind of type definition
#[derive(Debug, Clone, Serialize, Deserialize)]
pub enum TypeKind {
    Struct,
    Enum,
    Union,
    TypeAlias,
    Trait,
}

/// Information about a field or enum variant
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct FieldInfo {
    /// Name of the field
    pub name: String,
    /// Type of the field
    pub field_type: String,
    /// Documentation for the field
    pub description: String,
    /// Visibility of the field
    pub visibility: Visibility,
}

/// Visibility levels
#[derive(Debug, Clone, Serialize, Deserialize)]
pub enum Visibility {
    Public,
    Private,
    Restricted(String),
}

// ================================================================================================
// EXAMPLE-RELATED STRUCTURES
// ================================================================================================

/// Code example extracted from documentation
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct CodeExample {
    /// Title of the example
    pub title: String,
    /// Description of what the example demonstrates
    pub description: String,
    /// The actual code
    pub code: String,
    /// Programming language (usually "rust")
    pub language: String,
    /// Whether this example can be executed
    pub runnable: bool,
    /// Expected output when run
    pub expected_output: Option<String>,
}

/// Result of code execution
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct ExecutionResult {
    /// Standard output
    pub stdout: String,
    /// Standard error
    pub stderr: String,
    /// Exit code
    pub exit_code: i32,
    /// Time taken to execute
    pub execution_time: Duration,
    /// Memory used during execution
    pub memory_used: usize,
    /// Raw output data
    pub output: String,
}

// ================================================================================================
// INTERACTIVE DOCUMENTATION STRUCTURES
// ================================================================================================

/// Interactive documentation with live examples and features
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct InteractiveDocumentation {
    /// Base API reference
    pub api_reference: ApiReference,
    /// Live executable examples
    pub live_examples: Vec<LiveCodeExample>,
    /// Searchable index
    pub searchable_index: SearchIndex,
    /// Interactive tutorials
    pub interactive_tutorials: Vec<InteractiveTutorial>,
    /// Visualizations
    pub visualizations: Vec<ApiVisualization>,
    /// Playground configuration
    pub playground_config: PlaygroundConfig,
}

/// Live code example with execution capabilities
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct LiveCodeExample {
    /// Original code example
    pub original_example: CodeExample,
    /// Execution result
    pub execution_result: ExecutionResult,
    /// Interactive UI elements
    pub interactive_elements: Vec<InteractiveElement>,
    /// Visualization of the example
    pub visualization: ExampleVisualization,
    /// Whether the code can be edited
    pub editable: bool,
    /// Whether to provide real-time feedback
    pub real_time_feedback: bool,
}

/// Interactive element for examples
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct InteractiveElement {
    /// Type of interactive element
    pub element_type: InteractiveElementType,
    /// Unique identifier
    pub id: String,
    /// Display label
    pub label: String,
    /// Action to perform
    pub action: String,
    /// Target for the action
    pub target: String,
}

/// Types of interactive elements
#[derive(Debug, Clone, Serialize, Deserialize)]
pub enum InteractiveElementType {
    Button,
    Slider,
    Toggle,
    Input,
    Dropdown,
}

/// Visualization for code examples
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct ExampleVisualization {
    /// Type of visualization
    pub visualization_type: VisualizationType,
    /// Data to visualize
    pub data: String,
    /// Whether visualization is interactive
    pub interactive: bool,
    /// Whether to update in real-time
    pub real_time_updates: bool,
    /// Visualization configuration
    pub config: VisualizationConfig,
}

/// Types of visualizations
#[derive(Debug, Clone, Serialize, Deserialize)]
pub enum VisualizationType {
    FlowChart,
    Graph,
    Timeline,
    Tree,
    Network,
    Chart,
}

/// Configuration for visualizations
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct VisualizationConfig {
    /// Width in pixels
    pub width: u32,
    /// Height in pixels
    pub height: u32,
    /// Theme name
    pub theme: String,
    /// Whether animations are enabled
    pub animation_enabled: bool,
}

/// Interactive tutorial
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct InteractiveTutorial {
    /// Tutorial title
    pub title: String,
    /// Tutorial description
    pub description: String,
    /// Tutorial steps
    pub steps: Vec<TutorialStep>,
    /// Difficulty level
    pub difficulty: TutorialDifficulty,
    /// Estimated completion time
    pub estimated_time: Duration,
}

/// Individual tutorial step
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct TutorialStep {
    /// Step title
    pub title: String,
    /// Step content
    pub content: String,
    /// Code example for this step
    pub code_example: Option<CodeExample>,
    /// Interactive elements for this step
    pub interactive_elements: Vec<InteractiveElement>,
    /// Expected outcome
    pub expected_outcome: String,
}

/// Tutorial difficulty levels
#[derive(Debug, Clone, Serialize, Deserialize)]
pub enum TutorialDifficulty {
    Beginner,
    Intermediate,
    Advanced,
    Expert,
}

/// API visualization
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct ApiVisualization {
    /// Visualization title
    pub title: String,
    /// Visualization type
    pub visualization_type: VisualizationType,
    /// Data to visualize
    pub data: ApiVisualizationData,
    /// Configuration
    pub config: VisualizationConfig,
}

/// Data for API visualizations
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct ApiVisualizationData {
    /// Nodes in the visualization
    pub nodes: Vec<VisualizationNode>,
    /// Edges between nodes
    pub edges: Vec<VisualizationEdge>,
    /// Metadata
    pub metadata: HashMap<String, String>,
}

/// Node in a visualization
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct VisualizationNode {
    /// Node ID
    pub id: String,
    /// Node label
    pub label: String,
    /// Node type
    pub node_type: String,
    /// Node properties
    pub properties: HashMap<String, String>,
}

/// Edge in a visualization
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct VisualizationEdge {
    /// Source node ID
    pub source: String,
    /// Target node ID
    pub target: String,
    /// Edge label
    pub label: String,
    /// Edge type
    pub edge_type: String,
    /// Edge properties
    pub properties: HashMap<String, String>,
}

// ================================================================================================
// WEBASSEMBLY PLAYGROUND STRUCTURES
// ================================================================================================

/// WebAssembly playground configuration
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct WasmPlayground {
    /// HTML template for the playground
    pub html_template: String,
    /// JavaScript code for WASM bindings
    pub javascript_code: String,
    /// CSS styling for the playground
    pub css_styling: String,
    /// Rust code template
    pub rust_code: String,
    /// Build instructions
    pub build_instructions: Vec<String>,
}

/// WASM binding for Rust code
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct WasmBinding {
    /// Rust name
    pub rust_name: String,
    /// JavaScript wrapper name
    pub js_name: String,
    /// Available methods
    pub methods: Vec<WasmMethod>,
    /// Usage examples
    pub examples: Vec<String>,
}

/// WASM method binding
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct WasmMethod {
    /// Method name
    pub name: String,
    /// JavaScript signature
    pub js_signature: String,
    /// Method description
    pub description: String,
}

/// UI component for interactive features
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct UIComponent {
    /// Component name
    pub name: String,
    /// Component type
    pub component_type: UIComponentType,
    /// Component properties
    pub props: Vec<(String, String)>,
    /// HTML template
    pub template: String,
}

/// Types of UI components
#[derive(Debug, Clone, Serialize, Deserialize)]
pub enum UIComponentType {
    CodeEditor,
    OutputPanel,
    ApiExplorer,
    ExampleGallery,
    SearchBox,
    NavigationMenu,
}

// ================================================================================================
// SEARCH AND INDEXING STRUCTURES
// ================================================================================================

/// Search index for API elements
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct SearchIndex {
    /// Indexed items
    pub items: Vec<SearchItem>,
    /// Search metadata
    pub metadata: SearchMetadata,
}

impl SearchIndex {
    /// Create a new empty search index
    pub fn new() -> Self {
        Self {
            items: Vec::new(),
            metadata: SearchMetadata::default(),
        }
    }

    /// Add an item to the search index
    pub fn add_item(&mut self, item: SearchItem) -> Result<()> {
        self.items.push(item);
        self.metadata.total_items += 1;
        Ok(())
    }

    /// Search for items matching a query
    pub fn search(&self, query: &str) -> Vec<&SearchItem> {
        self.items
            .iter()
            .filter(|item| {
                item.name.to_lowercase().contains(&query.to_lowercase())
                    || item
                        .description
                        .to_lowercase()
                        .contains(&query.to_lowercase())
                    || item
                        .keywords
                        .iter()
                        .any(|keyword| keyword.to_lowercase().contains(&query.to_lowercase()))
            })
            .collect()
    }
}

impl Default for SearchIndex {
    fn default() -> Self {
        Self::new()
    }
}

/// Individual search item
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct SearchItem {
    /// Item name
    pub name: String,
    /// Type of item
    pub item_type: SearchItemType,
    /// Item description
    pub description: String,
    /// Path to the item
    pub path: String,
    /// Search keywords
    pub keywords: Vec<String>,
    /// Relevance score
    pub relevance_score: f64,
}

/// Types of searchable items
#[derive(Debug, Clone, Serialize, Deserialize)]
pub enum SearchItemType {
    Trait,
    Type,
    Method,
    Function,
    Example,
    Tutorial,
    Documentation,
}

/// Search metadata
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct SearchMetadata {
    /// Total number of indexed items
    pub total_items: usize,
    /// Index creation time
    pub created_at: String,
    /// Last update time
    pub updated_at: String,
    /// Index version
    pub version: String,
}

impl Default for SearchMetadata {
    fn default() -> Self {
        let now = chrono::Utc::now().to_string();
        Self {
            total_items: 0,
            created_at: now.clone(),
            updated_at: now,
            version: "1.0.0".to_string(),
        }
    }
}

/// Enhanced search index with multiple search engines
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct EnhancedSearchIndex {
    /// Semantic search engine
    pub semantic_search: SemanticSearchEngine,
    /// Type-based search engine
    pub type_based_search: TypeSearchEngine,
    /// Usage pattern search engine
    pub usage_pattern_search: UsagePatternSearchEngine,
    /// Similarity search engine
    pub similarity_search: SimilaritySearchEngine,
    /// Auto-complete engine
    pub auto_complete_engine: AutoCompleteEngine,
    /// Search analytics
    pub search_analytics: SearchAnalytics,
}

/// Semantic search engine
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct SemanticSearchEngine {
    /// Semantic index
    pub index: HashMap<String, Vec<f64>>,
    /// Search model configuration
    pub model_config: SemanticModelConfig,
}

impl SemanticSearchEngine {
    /// Create a new semantic search engine
    pub fn new() -> Self {
        Self {
            index: HashMap::new(),
            model_config: SemanticModelConfig::default(),
        }
    }

    /// Index a trait semantically
    pub fn index_trait(&mut self, trait_info: &TraitInfo) -> Result<()> {
        // In a real implementation, this would use NLP models to create embeddings
        let embedding = vec![0.0; 128]; // Placeholder embedding
        self.index.insert(trait_info.name.clone(), embedding);
        Ok(())
    }

    /// Index an example semantically
    pub fn index_example(&mut self, example: &CodeExample) -> Result<()> {
        // In a real implementation, this would analyze code semantics
        let embedding = vec![0.0; 128]; // Placeholder embedding
        self.index.insert(example.title.clone(), embedding);
        Ok(())
    }
}

impl Default for SemanticSearchEngine {
    fn default() -> Self {
        Self::new()
    }
}

/// Configuration for semantic search models
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct SemanticModelConfig {
    /// Model name
    pub model_name: String,
    /// Embedding dimension
    pub embedding_dim: usize,
    /// Similarity threshold
    pub similarity_threshold: f64,
}

impl Default for SemanticModelConfig {
    fn default() -> Self {
        Self {
            model_name: "sentence-transformers/all-MiniLM-L6-v2".to_string(),
            embedding_dim: 384,
            similarity_threshold: 0.7,
        }
    }
}

/// Type-based search engine
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct TypeSearchEngine {
    /// Type signatures index
    pub signatures: HashMap<String, TypeSignature>,
    /// Type compatibility matrix
    pub compatibility_matrix: HashMap<String, Vec<String>>,
}

impl TypeSearchEngine {
    /// Create a new type search engine
    pub fn new() -> Self {
        Self {
            signatures: HashMap::new(),
            compatibility_matrix: HashMap::new(),
        }
    }

    /// Index trait signatures
    pub fn index_trait_signatures(&mut self, trait_info: &TraitInfo) -> Result<()> {
        for method in &trait_info.methods {
            self.signatures.insert(
                method.name.clone(),
                TypeSignature {
                    signature: method.signature.clone(),
                    return_type: method.return_type.clone(),
                    parameters: method.parameters.clone(),
                },
            );
        }
        Ok(())
    }

    /// Index type definition
    pub fn index_type_definition(&mut self, type_info: &TypeInfo) -> Result<()> {
        // Index type compatibility information
        self.compatibility_matrix
            .insert(type_info.name.clone(), type_info.trait_impls.clone());
        Ok(())
    }
}

impl Default for TypeSearchEngine {
    fn default() -> Self {
        Self::new()
    }
}

/// Type signature information
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct TypeSignature {
    /// Full signature
    pub signature: String,
    /// Return type
    pub return_type: String,
    /// Parameters
    pub parameters: Vec<ParameterInfo>,
}

/// Usage pattern search engine
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct UsagePatternSearchEngine {
    /// Pattern index
    pub patterns: HashMap<String, UsagePattern>,
    /// Pattern frequency
    pub frequency: HashMap<String, usize>,
}

impl UsagePatternSearchEngine {
    /// Create a new usage pattern search engine
    pub fn new() -> Self {
        Self {
            patterns: HashMap::new(),
            frequency: HashMap::new(),
        }
    }

    /// Index usage patterns from examples
    pub fn index_usage_patterns(&mut self, example: &CodeExample) -> Result<()> {
        // Analyze code patterns
        let pattern = UsagePattern {
            pattern_type: PatternType::FunctionCall,
            code_snippet: example.code.clone(),
            frequency: 1,
            confidence: 0.8,
        };
        self.patterns.insert(example.title.clone(), pattern);
        Ok(())
    }
}

impl Default for UsagePatternSearchEngine {
    fn default() -> Self {
        Self::new()
    }
}

/// Usage pattern information
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct UsagePattern {
    /// Type of pattern
    pub pattern_type: PatternType,
    /// Code snippet
    pub code_snippet: String,
    /// Pattern frequency
    pub frequency: usize,
    /// Confidence score
    pub confidence: f64,
}

/// Types of usage patterns
#[derive(Debug, Clone, Serialize, Deserialize)]
pub enum PatternType {
    FunctionCall,
    MethodChaining,
    ErrorHandling,
    Initialization,
    Configuration,
}

/// Similarity search engine
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct SimilaritySearchEngine {
    /// Similarity matrix
    pub similarity_matrix: HashMap<String, HashMap<String, f64>>,
    /// Similarity algorithms
    pub algorithms: Vec<SimilarityAlgorithm>,
}

impl SimilaritySearchEngine {
    /// Create a new similarity search engine
    pub fn new() -> Self {
        Self {
            similarity_matrix: HashMap::new(),
            algorithms: vec![SimilarityAlgorithm::Cosine, SimilarityAlgorithm::Jaccard],
        }
    }

    /// Index trait similarities
    pub fn index_trait_similarities(&mut self, trait_info: &TraitInfo) -> Result<()> {
        // Calculate similarities with other traits
        let similarities = HashMap::new(); // Placeholder
        self.similarity_matrix
            .insert(trait_info.name.clone(), similarities);
        Ok(())
    }
}

impl Default for SimilaritySearchEngine {
    fn default() -> Self {
        Self::new()
    }
}

/// Similarity algorithms
#[derive(Debug, Clone, Serialize, Deserialize)]
pub enum SimilarityAlgorithm {
    Cosine,
    Jaccard,
    Euclidean,
    Manhattan,
}

/// Auto-complete engine
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct AutoCompleteEngine {
    /// Completion trie
    pub completions: HashMap<String, CompletionNode>,
    /// Completion statistics
    pub stats: CompletionStats,
}

impl AutoCompleteEngine {
    /// Create a new auto-complete engine
    pub fn new() -> Self {
        Self {
            completions: HashMap::new(),
            stats: CompletionStats::default(),
        }
    }

    /// Add a completion
    pub fn add_completion(&mut self, text: &str, completion_type: CompletionType) -> Result<()> {
        let node = CompletionNode {
            text: text.to_string(),
            completion_type,
            frequency: 1,
            score: 1.0,
        };
        self.completions.insert(text.to_string(), node);
        self.stats.total_completions += 1;
        Ok(())
    }

    /// Get completions for a prefix
    pub fn get_completions(&self, prefix: &str) -> Vec<&CompletionNode> {
        self.completions
            .values()
            .filter(|node| node.text.starts_with(prefix))
            .collect()
    }
}

impl Default for AutoCompleteEngine {
    fn default() -> Self {
        Self::new()
    }
}

/// Completion node
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct CompletionNode {
    /// Completion text
    pub text: String,
    /// Type of completion
    pub completion_type: CompletionType,
    /// Usage frequency
    pub frequency: usize,
    /// Relevance score
    pub score: f64,
}

/// Types of completions
#[derive(Debug, Clone, Serialize, Deserialize)]
pub enum CompletionType {
    Trait,
    Type,
    Method,
    Function,
    Variable,
    Keyword,
}

/// Completion statistics
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct CompletionStats {
    /// Total number of completions
    pub total_completions: usize,
    /// Most used completions
    pub popular_completions: Vec<String>,
    /// Completion accuracy
    pub accuracy: f64,
}

impl Default for CompletionStats {
    fn default() -> Self {
        Self {
            total_completions: 0,
            popular_completions: Vec::new(),
            accuracy: 0.0,
        }
    }
}

/// Search analytics
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct SearchAnalytics {
    /// Search queries performed
    pub query_count: usize,
    /// Most popular queries
    pub popular_queries: Vec<String>,
    /// Search performance metrics
    pub performance_metrics: SearchPerformanceMetrics,
}

impl SearchAnalytics {
    /// Create new search analytics
    pub fn new() -> Self {
        Self {
            query_count: 0,
            popular_queries: Vec::new(),
            performance_metrics: SearchPerformanceMetrics::default(),
        }
    }
}

impl Default for SearchAnalytics {
    fn default() -> Self {
        Self::new()
    }
}

/// Search performance metrics
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct SearchPerformanceMetrics {
    /// Average search time in milliseconds
    pub avg_search_time_ms: f64,
    /// Search success rate
    pub success_rate: f64,
    /// Index size in bytes
    pub index_size_bytes: usize,
}

impl Default for SearchPerformanceMetrics {
    fn default() -> Self {
        Self {
            avg_search_time_ms: 0.0,
            success_rate: 0.0,
            index_size_bytes: 0,
        }
    }
}

// ================================================================================================
// TUTORIAL SYSTEM STRUCTURES
// ================================================================================================

/// Template for generating tutorials
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct TutorialTemplate {
    /// Template name
    pub name: String,
    /// Template content
    pub content: String,
    /// Template variables
    pub variables: HashMap<String, String>,
    /// Required API elements
    pub required_elements: Vec<String>,
}

// ================================================================================================
// TESTS
// ================================================================================================

#[allow(non_snake_case)]
#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_api_reference_creation() {
        let api_ref = ApiReference {
            crate_name: "test-crate".to_string(),
            version: "1.0.0".to_string(),
            traits: Vec::new(),
            types: Vec::new(),
            examples: Vec::new(),
            cross_references: HashMap::new(),
            metadata: ApiMetadata::default(),
        };

        assert_eq!(api_ref.crate_name, "test-crate");
        assert_eq!(api_ref.version, "1.0.0");
    }

    #[test]
    fn test_search_index() {
        let mut index = SearchIndex::new();
        let item = SearchItem {
            name: "TestTrait".to_string(),
            item_type: SearchItemType::Trait,
            description: "A test trait".to_string(),
            path: "test::TestTrait".to_string(),
            keywords: vec!["test".to_string(), "trait".to_string()],
            relevance_score: 1.0,
        };

        index.add_item(item).expect("add_item should succeed");
        assert_eq!(index.items.len(), 1);
        assert_eq!(index.metadata.total_items, 1);

        let results = index.search("test");
        assert_eq!(results.len(), 1);
        assert_eq!(results[0].name, "TestTrait");
    }

    #[test]
    fn test_trait_info_default() {
        let trait_info = TraitInfo::default();
        assert!(trait_info.name.is_empty());
        assert!(trait_info.methods.is_empty());
        assert!(trait_info.associated_types.is_empty());
    }

    #[test]
    fn test_code_example() {
        let example = CodeExample {
            title: "Basic Usage".to_string(),
            description: "Shows basic usage".to_string(),
            code: "fn main() {}".to_string(),
            language: "rust".to_string(),
            runnable: true,
            expected_output: Some("Success".to_string()),
        };

        assert_eq!(example.title, "Basic Usage");
        assert!(example.runnable);
    }

    #[test]
    fn test_auto_complete_engine() {
        let mut engine = AutoCompleteEngine::new();
        engine
            .add_completion("TestTrait", CompletionType::Trait)
            .expect("expected valid value");
        engine
            .add_completion("TestType", CompletionType::Type)
            .expect("expected valid value");

        let completions = engine.get_completions("Test");
        assert_eq!(completions.len(), 2);

        let completions = engine.get_completions("TestT");
        assert_eq!(completions.len(), 2);

        let completions = engine.get_completions("TestTr");
        assert_eq!(completions.len(), 1);
        assert_eq!(completions[0].text, "TestTrait");
    }

    #[test]
    fn test_serialization() {
        let example = CodeExample {
            title: "Test".to_string(),
            description: "Test example".to_string(),
            code: "println!(\"Hello\");".to_string(),
            language: "rust".to_string(),
            runnable: true,
            expected_output: None,
        };

        let serialized = serde_json::to_string(&example).unwrap_or_default();
        let deserialized: CodeExample =
            serde_json::from_str(&serialized).expect("valid JSON operation");

        assert_eq!(example.title, deserialized.title);
        assert_eq!(example.code, deserialized.code);
    }
}
