dampen-core 0.3.2

pub mod attribute_standard;
pub mod canvas;
pub mod color_validator;
pub mod error;
pub mod gradient;
pub mod lexer;
pub mod style_parser;
pub mod theme_parser;

use crate::expr::tokenize_binding_expr;
use crate::expr::{BindingExpr, Expr, LiteralExpr};
use crate::ir::style::StyleProperties;
use crate::ir::theme::WidgetState;
use crate::ir::{
    AttributeValue, Breakpoint, DampenDocument, EventBinding, EventKind, InterpolatedPart,
    SchemaVersion, Span, WidgetKind, WidgetNode,
};
use crate::parser::error::{ParseError, ParseErrorKind};
use chrono::{NaiveDate, NaiveTime};
use roxmltree::{Document, Node, NodeType};
use std::collections::HashMap;

/// Maximum schema version supported by this framework release.
///
/// Files declaring a version higher than this will be rejected with an error.
/// Update this constant when the framework adds support for new schema versions.
pub const MAX_SUPPORTED_VERSION: SchemaVersion = SchemaVersion { major: 1, minor: 1 };

/// Parse a version string in "major.minor" format into a SchemaVersion.
///
/// # Arguments
///
/// * `version_str` - Raw version string from XML attribute (e.g., "1.0")
/// * `span` - Source location for error reporting
///
/// # Returns
///
/// `Ok(SchemaVersion)` on success, `Err(ParseError)` for invalid formats.
///
/// # Examples
///
/// ```ignore
/// let v = parse_version_string("1.0", span)?;
/// assert_eq!(v.major, 1);
/// assert_eq!(v.minor, 0);
/// ```
pub fn parse_version_string(version_str: &str, span: Span) -> Result<SchemaVersion, ParseError> {
    let trimmed = version_str.trim();

    // Reject empty strings
    if trimmed.is_empty() {
        return Err(ParseError {
            kind: ParseErrorKind::InvalidValue,
            message: "Version attribute cannot be empty".to_string(),
            span,
            suggestion: Some("Use format: version=\"1.0\"".to_string()),
        });
    }

    // Split on "." and validate exactly 2 parts
    let parts: Vec<&str> = trimmed.split('.').collect();
    if parts.len() != 2 {
        return Err(ParseError {
            kind: ParseErrorKind::InvalidValue,
            message: format!(
                "Invalid version format '{}'. Expected 'major.minor' (e.g., '1.0')",
                trimmed
            ),
            span,
            suggestion: Some("Use format: version=\"1.0\"".to_string()),
        });
    }

    // Parse major version
    let major = parts[0].parse::<u16>().map_err(|_| ParseError {
        kind: ParseErrorKind::InvalidValue,
        message: format!(
            "Invalid version format '{}'. Expected 'major.minor' (e.g., '1.0')",
            trimmed
        ),
        span,
        suggestion: Some("Use format: version=\"1.0\"".to_string()),
    })?;

    // Parse minor version
    let minor = parts[1].parse::<u16>().map_err(|_| ParseError {
        kind: ParseErrorKind::InvalidValue,
        message: format!(
            "Invalid version format '{}'. Expected 'major.minor' (e.g., '1.0')",
            trimmed
        ),
        span,
        suggestion: Some("Use format: version=\"1.0\"".to_string()),
    })?;

    Ok(SchemaVersion { major, minor })
}

/// Validate that a parsed version is supported by this framework.
///
/// # Arguments
///
/// * `version` - Parsed version to validate
/// * `span` - Source location for error reporting
///
/// # Returns
///
/// `Ok(())` if the version is supported, `Err(ParseError)` if the version
/// is newer than `MAX_SUPPORTED_VERSION`.
pub fn validate_version_supported(version: &SchemaVersion, span: Span) -> Result<(), ParseError> {
    if (version.major, version.minor) > (MAX_SUPPORTED_VERSION.major, MAX_SUPPORTED_VERSION.minor) {
        return Err(ParseError {
            kind: ParseErrorKind::UnsupportedVersion,
            message: format!(
                "Schema version {}.{} is not supported. Maximum supported version: {}.{}",
                version.major,
                version.minor,
                MAX_SUPPORTED_VERSION.major,
                MAX_SUPPORTED_VERSION.minor
            ),
            span,
            suggestion: Some(format!(
                "Upgrade dampen-core to support v{}.{}, or use version=\"{}.{}\"",
                version.major,
                version.minor,
                MAX_SUPPORTED_VERSION.major,
                MAX_SUPPORTED_VERSION.minor
            )),
        });
    }
    Ok(())
}

/// Warning about a widget requiring a higher schema version than declared.
///
/// This is non-blocking validation - widgets may work but compatibility is not guaranteed.
#[derive(Debug, Clone, PartialEq)]
pub struct ValidationWarning {
    /// The widget that requires a higher version
    pub widget_kind: WidgetKind,
    /// The schema version declared in the document
    pub declared_version: SchemaVersion,
    /// The minimum version required by the widget
    pub required_version: SchemaVersion,
    /// Source location of the widget
    pub span: Span,
}

impl ValidationWarning {
    /// Format the warning as a human-readable message
    pub fn format_message(&self) -> String {
        format!(
            "Widget '{}' requires schema v{}.{} but document declares v{}.{}",
            self.widget_kind,
            self.required_version.major,
            self.required_version.minor,
            self.declared_version.major,
            self.declared_version.minor
        )
    }

    /// Get a suggestion for resolving the warning
    pub fn suggestion(&self) -> String {
        format!(
            "Update to <dampen version=\"{}.{}\"> or remove this widget",
            self.required_version.major, self.required_version.minor
        )
    }
}

/// Validate that all widgets in the document are compatible with the declared schema version.
///
/// Returns warnings (not errors) for widgets that require a higher version than declared.
/// This is non-blocking validation to help developers identify potential compatibility issues.
///
/// # Arguments
///
/// * `document` - The parsed document to validate
///
/// # Returns
///
/// A vector of `ValidationWarning` for widgets requiring higher versions.
/// Empty vector means all widgets are compatible with the declared version.
///
/// # Examples
///
/// ```rust
/// use dampen_core::{parse, validate_widget_versions};
///
/// // Implicit document defaults to v1.0, but Canvas requires v1.1
/// let xml = r#"<canvas width="400" height="200" program="{chart}" />"#;
/// let doc = parse(xml).unwrap();
/// let warnings = validate_widget_versions(&doc);
/// assert_eq!(warnings.len(), 1); // Canvas requires v1.1
/// ```
pub fn validate_widget_versions(document: &DampenDocument) -> Vec<ValidationWarning> {
    let mut warnings = Vec::new();
    validate_widget_tree(&document.root, &document.version, &mut warnings);
    warnings
}

/// Recursively validate widget tree for version compatibility
fn validate_widget_tree(
    node: &WidgetNode,
    doc_version: &SchemaVersion,
    warnings: &mut Vec<ValidationWarning>,
) {
    let min_version = node.kind.minimum_version();

    // Check if widget requires a higher version than declared
    if (min_version.major, min_version.minor) > (doc_version.major, doc_version.minor) {
        warnings.push(ValidationWarning {
            widget_kind: node.kind.clone(),
            declared_version: *doc_version,
            required_version: min_version,
            span: node.span,
        });
    }

    // Recursively check children
    for child in &node.children {
        validate_widget_tree(child, doc_version, warnings);
    }
}

/// Preprocess XML to handle state attributes without XML namespaces.
///
/// Converts attributes like `hover:background` to `hover__state__background`
/// to avoid "unknown namespace prefix" errors from roxmltree.
fn preprocess_xml(xml: &str) -> String {
    let mut result = xml.to_string();
    let states = ["hover", "active", "focus", "disabled"];
    let prefixes = [' ', '\n', '\t', '\r'];

    for state in states {
        for prefix in prefixes {
            // We want to replace " hover:" with " hover__state__"
            // Note: We deliberately remove the colon to make it a valid non-namespaced attribute
            let target = format!("{}{}:", prefix, state);
            let sub = format!("{}{}_state_", prefix, state);
            result = result.replace(&target, &sub);
        }
    }
    result
}

/// Parse XML markup into a DampenDocument.
///
/// This is the main entry point for the parser. It takes XML markup and
/// converts it into the Intermediate Representation (IR) suitable for
/// rendering or code generation.
///
/// # Arguments
///
/// * `xml` - XML markup string
///
/// # Returns
///
/// `Ok(DampenDocument)` on success, `Err(ParseError)` on failure
///
/// # Examples
///
/// ```rust
/// use dampen_core::parse;
///
/// let xml = r#"<dampen><column><text value="Hello" /></column></dampen>"#;
/// let doc = parse(xml).unwrap();
/// assert_eq!(doc.root.children.len(), 1);
/// ```
///
/// # Errors
///
/// Returns `ParseError` for:
/// - Invalid XML syntax
/// - Unknown widget elements
/// - Invalid attribute values
/// - Malformed binding expressions
pub fn parse(xml: &str) -> Result<DampenDocument, ParseError> {
    // Preprocess XML to handle state attributes
    let processed_xml = preprocess_xml(xml);

    // Parse XML using roxmltree
    let doc = Document::parse(&processed_xml).map_err(|e| ParseError {
        kind: ParseErrorKind::XmlSyntax,
        message: e.to_string(),
        span: Span::new(0, 0, 1, 1),
        suggestion: None,
    })?;

    // Find root element (skip XML declaration)
    let root = doc.root().first_child().ok_or_else(|| ParseError {
        kind: ParseErrorKind::XmlSyntax,
        message: "No root element found".to_string(),
        span: Span::new(0, 0, 1, 1),
        suggestion: None,
    })?;

    // Check if root is <dampen> wrapper
    let root_tag = root.tag_name().name();

    if root_tag == "dampen" {
        // Parse <dampen> document with themes and widgets
        parse_dampen_document(root, xml)
    } else {
        // Parse direct widget (backward compatibility)
        // Default to version 1.0 for backward compatibility
        let root_widget = parse_node(root, xml)?;

        // Validate nesting constraints
        validate_nesting_constraints(&root_widget, None)?;

        Ok(DampenDocument {
            version: SchemaVersion::default(),
            root: root_widget,
            themes: HashMap::new(),
            style_classes: HashMap::new(),
            global_theme: None,
            follow_system: true,
        })
    }
}

/// Validate widget-specific required attributes
fn validate_widget_attributes(
    kind: &WidgetKind,
    attributes: &std::collections::HashMap<String, AttributeValue>,
    span: Span,
) -> Result<(), ParseError> {
    match kind {
        WidgetKind::ComboBox | WidgetKind::PickList => {
            require_non_empty_attribute(
                kind,
                "options",
                attributes,
                span,
                "Add a comma-separated list: options=\"Option1,Option2\"",
            )?;
        }
        WidgetKind::DatePicker => {
            validate_date_format(kind, attributes, span)?;
            validate_date_range(kind, attributes, span)?;
        }
        WidgetKind::TimePicker => {
            validate_time_format(kind, attributes, span)?;
        }
        WidgetKind::Canvas => {
            // Width and height are optional (defaulted in builder if missing)
            // But validation ensures they are numbers if present
            validate_numeric_range(kind, "width", attributes, span, 50..=4000)?;
            validate_numeric_range(kind, "height", attributes, span, 50..=4000)?;

            // T069: Warn if both 'program' attribute and children shapes are present
            if attributes.contains_key("program") {
                // We need access to children to check this.
                // But validate_widget_attributes doesn't have children.
                // I should probably move this check to where children are available,
                // or change the signature.
                // Actually, I can check this in parse_node or validate_canvas_children.
            }
        }
        WidgetKind::Grid => {
            require_attribute(
                kind,
                "columns",
                attributes,
                span,
                "Add columns attribute: columns=\"5\"",
            )?;
            validate_numeric_range(kind, "columns", attributes, span, 1..=20)?;
        }
        WidgetKind::Tooltip => {
            require_attribute(
                kind,
                "message",
                attributes,
                span,
                "Add message attribute: message=\"Help text\"",
            )?;
        }
        WidgetKind::For => {
            require_attribute(
                kind,
                "each",
                attributes,
                span,
                "Add each attribute: each=\"item\"",
            )?;
            require_attribute(
                kind,
                "in",
                attributes,
                span,
                "Add in attribute: in=\"{items}\"",
            )?;
        }
        WidgetKind::CanvasRect
        | WidgetKind::CanvasCircle
        | WidgetKind::CanvasLine
        | WidgetKind::CanvasText
        | WidgetKind::CanvasGroup => {
            canvas::validate_shape_attributes(kind, attributes, span)?;
        }
        _ => {}
    }
    Ok(())
}

/// Helper to validate date format for static value
fn validate_date_format(
    kind: &WidgetKind,
    attributes: &HashMap<String, AttributeValue>,
    span: Span,
) -> Result<(), ParseError> {
    if let Some(AttributeValue::Static(value)) = attributes.get("value") {
        let format = if let Some(AttributeValue::Static(f)) = attributes.get("format") {
            f.as_str()
        } else {
            "%Y-%m-%d"
        };

        if NaiveDate::parse_from_str(value, format).is_err() {
            return Err(ParseError {
                kind: ParseErrorKind::InvalidDateFormat,
                message: format!(
                    "Invalid date format for {:?}: '{}' does not match format '{}'",
                    kind, value, format
                ),
                span,
                suggestion: Some(
                    "Use ISO 8601 format (YYYY-MM-DD) or specify correct format attribute (e.g., format=\"%d/%m/%Y\")".to_string()
                ),
            });
        }
    }
    Ok(())
}

/// Helper to validate time format for static value
fn validate_time_format(
    kind: &WidgetKind,
    attributes: &HashMap<String, AttributeValue>,
    span: Span,
) -> Result<(), ParseError> {
    if let Some(AttributeValue::Static(value)) = attributes.get("value") {
        let format = if let Some(AttributeValue::Static(f)) = attributes.get("format") {
            f.as_str()
        } else {
            "%H:%M:%S"
        };

        if NaiveTime::parse_from_str(value, format).is_err() {
            return Err(ParseError {
                kind: ParseErrorKind::InvalidTimeFormat,
                message: format!(
                    "Invalid time format for {:?}: '{}' does not match format '{}'",
                    kind, value, format
                ),
                span,
                suggestion: Some(
                    "Use 24-hour format (HH:MM:SS) or specify correct format attribute (e.g., format=\"%I:%M %p\")".to_string()
                ),
            });
        }
    }
    Ok(())
}

/// Helper to validate date range (min <= max)
fn validate_date_range(
    kind: &WidgetKind,
    attributes: &HashMap<String, AttributeValue>,
    span: Span,
) -> Result<(), ParseError> {
    let min_date = if let Some(AttributeValue::Static(m)) = attributes.get("min_date") {
        NaiveDate::parse_from_str(m, "%Y-%m-%d").ok()
    } else {
        None
    };

    let max_date = if let Some(AttributeValue::Static(m)) = attributes.get("max_date") {
        NaiveDate::parse_from_str(m, "%Y-%m-%d").ok()
    } else {
        None
    };

    if let (Some(min), Some(max)) = (min_date, max_date)
        && min > max
    {
        return Err(ParseError {
            kind: ParseErrorKind::InvalidDateRange,
            message: format!(
                "Invalid date range for {:?}: min_date ({}) is after max_date ({})",
                kind, min, max
            ),
            span,
            suggestion: Some("Ensure min_date is before or equal to max_date".to_string()),
        });
    }
    Ok(())
}

/// Helper to require an attribute exists
fn require_attribute(
    kind: &WidgetKind,
    attr_name: &str,
    attributes: &HashMap<String, AttributeValue>,
    span: Span,
    suggestion: &str,
) -> Result<(), ParseError> {
    if !attributes.contains_key(attr_name) {
        return Err(ParseError {
            kind: ParseErrorKind::MissingAttribute,
            message: format!("{:?} widget requires '{}' attribute", kind, attr_name),
            span,
            suggestion: Some(suggestion.to_string()),
        });
    }
    Ok(())
}

/// Helper to require a non-empty attribute
fn require_non_empty_attribute(
    kind: &WidgetKind,
    attr_name: &str,
    attributes: &HashMap<String, AttributeValue>,
    span: Span,
    suggestion: &str,
) -> Result<(), ParseError> {
    match attributes.get(attr_name) {
        Some(AttributeValue::Static(value)) if !value.trim().is_empty() => Ok(()),
        _ => Err(ParseError {
            kind: ParseErrorKind::MissingAttribute,
            message: format!(
                "{:?} widget requires '{}' attribute to be non-empty",
                kind, attr_name
            ),
            span,
            suggestion: Some(suggestion.to_string()),
        }),
    }
}

/// Helper to validate numeric range
fn validate_numeric_range<T: PartialOrd + std::fmt::Display + std::str::FromStr>(
    kind: &WidgetKind,
    attr_name: &str,
    attributes: &HashMap<String, AttributeValue>,
    span: Span,
    range: std::ops::RangeInclusive<T>,
) -> Result<(), ParseError> {
    if let Some(AttributeValue::Static(value_str)) = attributes.get(attr_name)
        && let Ok(value) = value_str.parse::<T>()
        && !range.contains(&value)
    {
        return Err(ParseError {
            kind: ParseErrorKind::InvalidValue,
            message: format!(
                "{} for {:?} {} must be between {} and {}, found {}",
                attr_name,
                kind,
                attr_name,
                range.start(),
                range.end(),
                value
            ),
            span,
            suggestion: Some(format!(
                "Use {} value between {} and {}",
                attr_name,
                range.start(),
                range.end()
            )),
        });
    }
    Ok(())
}

/// Validate Tooltip widget has exactly one child
fn validate_tooltip_children(children: &[WidgetNode], span: Span) -> Result<(), ParseError> {
    if children.is_empty() {
        return Err(ParseError {
            kind: ParseErrorKind::InvalidValue,
            message: "Tooltip widget must have exactly one child widget".to_string(),
            span,
            suggestion: Some("Wrap a single widget in <tooltip></tooltip>".to_string()),
        });
    }
    if children.len() > 1 {
        return Err(ParseError {
            kind: ParseErrorKind::InvalidValue,
            message: format!(
                "Tooltip widget must have exactly one child, found {}",
                children.len()
            ),
            span,
            suggestion: Some("Wrap only one widget in <tooltip></tooltip>".to_string()),
        });
    }
    Ok(())
}

/// Validate Canvas widget children (must be shapes)
fn validate_canvas_children(
    attributes: &HashMap<String, AttributeValue>,
    children: &[WidgetNode],
    span: Span,
) -> Result<(), ParseError> {
    // T069: Warn if both 'program' attribute and children shapes are present
    if attributes.contains_key("program") && !children.is_empty() {
        // This is a warning-level check, but Dampen parser usually returns Result.
        // For now, let's treat it as a validation error or just a log?
        // Constitution says "Prefer helpful errors with suggestions".
        // If both are present, 'program' wins in the builder.
        // So we should probably error to avoid confusion.
        return Err(ParseError {
            kind: ParseErrorKind::InvalidValue,
            message: "Canvas cannot have both a 'program' attribute and child shapes".to_string(),
            span,
            suggestion: Some("Remove the 'program' attribute to use declarative shapes, or remove children to use a custom program".to_string()),
        });
    }

    canvas::validate_canvas_children(children, span)
}

/// Validate DatePicker/TimePicker has exactly one child
fn validate_datetime_picker_children(
    kind: &WidgetKind,
    children: &[WidgetNode],
    span: Span,
) -> Result<(), ParseError> {
    if children.is_empty() {
        return Err(ParseError {
            kind: ParseErrorKind::InvalidValue,
            message: format!(
                "{:?} widget must have exactly one child widget (the underlay)",
                kind
            ),
            span,
            suggestion: Some(format!(
                "Wrap a single widget (e.g., <button>) in <{}>",
                kind
            )),
        });
    }
    if children.len() > 1 {
        return Err(ParseError {
            kind: ParseErrorKind::InvalidValue,
            message: format!(
                "{:?} widget must have exactly one child, found {}",
                kind,
                children.len()
            ),
            span,
            suggestion: Some(format!("Wrap only one widget in <{}>", kind)),
        });
    }
    Ok(())
}

/// Validate ContextMenu has exactly 2 children: underlay + menu
fn validate_context_menu_children(children: &[WidgetNode], span: Span) -> Result<(), ParseError> {
    if children.len() != 2 {
        return Err(ParseError {
            kind: ParseErrorKind::InvalidValue,
            message: "ContextMenu requires exactly 2 children: underlay and menu".to_string(),
            span,
            suggestion: Some(
                "Add an underlay widget (1st child) and a <menu> element (2nd child)".to_string(),
            ),
        });
    }
    if children[1].kind != WidgetKind::Menu {
        return Err(ParseError {
            kind: ParseErrorKind::InvalidValue,
            message: "Second child of ContextMenu must be <menu>".to_string(),
            span: children[1].span,
            suggestion: None,
        });
    }
    Ok(())
}

/// Parse a single XML node into a WidgetNode
fn parse_node(node: Node, source: &str) -> Result<WidgetNode, ParseError> {
    // Only process element nodes
    if node.node_type() != NodeType::Element {
        return Err(ParseError {
            kind: ParseErrorKind::XmlSyntax,
            message: "Expected element node".to_string(),
            span: Span::new(0, 0, 1, 1),
            suggestion: None,
        });
    }

    // Get element name and map to WidgetKind
    let tag_name = node.tag_name().name();
    let kind = match tag_name {
        "column" => WidgetKind::Column,
        "row" => WidgetKind::Row,
        "container" => WidgetKind::Container,
        "scrollable" => WidgetKind::Scrollable,
        "stack" => WidgetKind::Stack,
        "text" => WidgetKind::Text,
        "image" => WidgetKind::Image,
        "svg" => WidgetKind::Svg,
        "button" => WidgetKind::Button,
        "text_input" => WidgetKind::TextInput,
        "checkbox" => WidgetKind::Checkbox,
        "slider" => WidgetKind::Slider,
        "pick_list" => WidgetKind::PickList,
        "toggler" => WidgetKind::Toggler,
        "space" => WidgetKind::Space,
        "rule" => WidgetKind::Rule,
        "radio" => WidgetKind::Radio,
        "combobox" => WidgetKind::ComboBox,
        "progress_bar" => WidgetKind::ProgressBar,
        "tooltip" => WidgetKind::Tooltip,
        "grid" => WidgetKind::Grid,
        "canvas" => WidgetKind::Canvas,
        "rect" => WidgetKind::CanvasRect,
        "circle" => WidgetKind::CanvasCircle,
        "line" => WidgetKind::CanvasLine,
        "canvas_text" => WidgetKind::CanvasText,
        "group" => WidgetKind::CanvasGroup,
        "date_picker" => WidgetKind::DatePicker,
        "time_picker" => WidgetKind::TimePicker,
        "color_picker" => WidgetKind::ColorPicker,
        "menu" => WidgetKind::Menu,
        "menu_item" => WidgetKind::MenuItem,
        "menu_separator" => WidgetKind::MenuSeparator,
        "context_menu" => WidgetKind::ContextMenu,
        "float" => WidgetKind::Float,
        "data_table" => WidgetKind::DataTable,
        "data_column" => WidgetKind::DataColumn,
        "tree_view" => WidgetKind::TreeView,
        "tree_node" => WidgetKind::TreeNode,
        "tab_bar" => WidgetKind::TabBar,
        "tab" => WidgetKind::Tab,
        "template" => WidgetKind::Custom("template".to_string()),
        "for" => WidgetKind::For,
        "if" => WidgetKind::If,
        unknown => {
            return Err(ParseError {
                kind: ParseErrorKind::UnknownWidget,
                message: format!("Unknown widget: {}", unknown),
                span: get_span(node, source),
                suggestion: Some(format!(
                    "Valid widgets are: {}",
                    WidgetKind::all_standard().join(", ")
                )),
            });
        }
    };

    // Parse attributes - separate breakpoint-prefixed and state-prefixed from regular
    let mut attributes = std::collections::HashMap::new();
    let mut breakpoint_attributes: HashMap<Breakpoint, HashMap<String, AttributeValue>> =
        HashMap::new();
    let mut inline_state_variants: HashMap<WidgetState, HashMap<String, AttributeValue>> =
        HashMap::new();
    let mut events = Vec::new();
    let mut id = None;

    // Pre-scan attributes for validation
    for attr in node.attributes() {
        if kind == WidgetKind::ColorPicker && attr.name() == "value" {
            color_validator::validate_color_format(attr.value(), get_span(node, source))?;
        }
    }

    for attr in node.attributes() {
        // Get full attribute name (including namespace prefix if present)
        let name = if let Some(ns) = attr.namespace() {
            // If attribute has a Dampen state namespace, find the prefix
            if ns.starts_with("urn:dampen:state") {
                // Find the namespace prefix by iterating through namespace declarations
                let prefix = node
                    .namespaces()
                    .find(|n| n.uri() == ns)
                    .and_then(|n| n.name())
                    .unwrap_or("");
                format!("{}:{}", prefix, attr.name())
            } else {
                attr.name().to_string()
            }
        } else {
            attr.name().to_string()
        };
        let value = attr.value();

        // Check for id attribute
        if name == "id" {
            id = Some(value.to_string());
            continue;
        }

        // Check for event attributes (on_click, on_change, etc.)
        if name.starts_with("on_") {
            let event_kind = match name.as_str() {
                "on_click" => Some(EventKind::CanvasClick), // Prefer specific Canvas variants if they exist
                "on_press" => Some(EventKind::Press),
                "on_release" => Some(EventKind::CanvasRelease),
                "on_drag" => Some(EventKind::CanvasDrag),
                "on_move" => Some(EventKind::CanvasMove),
                "on_change" => Some(EventKind::Change),
                "on_input" => Some(EventKind::Input),
                "on_submit" => Some(EventKind::Submit),
                "on_select" => Some(EventKind::Select),
                "on_toggle" => Some(EventKind::Toggle),
                "on_scroll" => Some(EventKind::Scroll),
                "on_cancel" => Some(EventKind::Cancel),
                "on_open" => Some(EventKind::Open),
                "on_close" => Some(EventKind::Close),
                "on_row_click" => Some(EventKind::RowClick),
                _ => None,
            };

            // Fallback for non-canvas widgets (or where CanvasClick isn't desired)
            let event_kind = if kind != WidgetKind::Canvas {
                match name.as_str() {
                    "on_click" => Some(EventKind::Click),
                    "on_release" => Some(EventKind::Release),
                    _ => event_kind,
                }
            } else {
                event_kind
            };

            if let Some(event) = event_kind {
                // Parse handler name and optional parameter
                // Syntax: "handler_name", "handler_name:{expression}", or "handler_name:'value'"
                let (handler_name, param) = if let Some(colon_pos) = value.find(':') {
                    let handler = value[..colon_pos].to_string();
                    let param_str = &value[colon_pos + 1..];

                    // Check for single-quoted string: 'value'
                    if param_str.starts_with('\'')
                        && param_str.ends_with('\'')
                        && param_str.len() >= 2
                    {
                        let quoted_value = &param_str[1..param_str.len() - 1];
                        // Create a static string binding expression
                        let expr = BindingExpr {
                            expr: Expr::Literal(LiteralExpr::String(quoted_value.to_string())),
                            span: Span::new(
                                colon_pos + 1,
                                colon_pos + 1 + param_str.len(),
                                1,
                                colon_pos as u32 + 1,
                            ),
                        };
                        (handler, Some(expr))
                    } else {
                        // Remove surrounding braces if present: {item.id} -> item.id
                        let param_clean = param_str.trim_matches('{').trim_matches('}');

                        // Parse parameter as binding expression
                        match crate::expr::tokenize_binding_expr(param_clean, 0, 1, 1) {
                            Ok(expr) => (handler, Some(expr)),
                            Err(_) => {
                                // If parsing fails, treat the whole string as handler name
                                (value.to_string(), None)
                            }
                        }
                    }
                } else {
                    (value.to_string(), None)
                };

                events.push(EventBinding {
                    event,
                    handler: handler_name,
                    param,
                    span: get_span(node, source),
                });
                continue;
            }
        }

        // Check for breakpoint-prefixed attributes (e.g., "mobile-spacing", "tablet-width")
        // Note: We use hyphen instead of colon to avoid XML namespace issues
        if let Some((prefix, attr_name)) = name.split_once('-')
            && let Ok(breakpoint) = crate::ir::layout::Breakpoint::parse(prefix)
        {
            let attr_value = parse_attribute_value(value, get_span(node, source))?;
            breakpoint_attributes
                .entry(breakpoint)
                .or_default()
                .insert(attr_name.to_string(), attr_value);
            continue;
        }

        if let Some((state_prefix, attr_name)) = name.split_once(':')
            && let Some(state) = WidgetState::from_prefix(state_prefix)
        {
            let attr_value = parse_attribute_value(value, get_span(node, source))?;
            inline_state_variants
                .entry(state)
                .or_default()
                .insert(attr_name.to_string(), attr_value);
            continue;
        }

        // Handle preprocessed state attributes (e.g. "hover_state_background")
        if let Some((state_prefix, attr_name)) = name.split_once("_state_")
            && let Some(state) = WidgetState::from_prefix(state_prefix)
        {
            let attr_value = parse_attribute_value(value, get_span(node, source))?;
            inline_state_variants
                .entry(state)
                .or_default()
                .insert(attr_name.to_string(), attr_value);
            continue;
        }

        // If state prefix is invalid, log warning and treat as regular attribute
        // TODO: Add proper logging when verbose mode is implemented

        // Parse attribute value (check for bindings)
        let attr_value = parse_attribute_value(value, get_span(node, source))?;
        attributes.insert(name.to_string(), attr_value);
    }

    // Extract class attribute into classes field
    let classes = if let Some(AttributeValue::Static(class_attr)) = attributes.get("class") {
        class_attr
            .split_whitespace()
            .map(|s| s.to_string())
            .collect()
    } else {
        Vec::new()
    };

    // Extract theme attribute into theme_ref field (supports both static and binding)
    let theme_ref = attributes.get("theme").cloned();

    // Parse children
    let mut children = Vec::new();
    for child in node.children() {
        if child.node_type() == NodeType::Element {
            children.push(parse_node(child, source)?);
        }
    }

    // Validate Tooltip has exactly one child
    if kind == WidgetKind::Tooltip {
        validate_tooltip_children(&children, get_span(node, source))?;
    }

    // Validate Canvas has no children (leaf widget)
    if kind == WidgetKind::Canvas {
        validate_canvas_children(&attributes, &children, get_span(node, source))?;
    }

    // Validate DatePicker/TimePicker has exactly one child
    if matches!(kind, WidgetKind::DatePicker | WidgetKind::TimePicker) {
        validate_datetime_picker_children(&kind, &children, get_span(node, source))?;
    }

    if kind == WidgetKind::ContextMenu {
        validate_context_menu_children(&children, get_span(node, source))?;
    }

    // Parse layout and style attributes into structured fields
    let layout = parse_layout_attributes(&kind, &attributes).map_err(|e| ParseError {
        kind: ParseErrorKind::InvalidValue,
        message: e,
        span: get_span(node, source),
        suggestion: None,
    })?;
    let style = parse_style_attributes(&attributes).map_err(|e| ParseError {
        kind: ParseErrorKind::InvalidValue,
        message: e,
        span: get_span(node, source),
        suggestion: None,
    })?;

    // Normalize deprecated attributes to standard names (with warnings)
    let _attr_warnings = attribute_standard::normalize_attributes(&kind, &mut attributes);
    // TODO: Log warnings in verbose mode

    // Validate widget-specific required attributes
    validate_widget_attributes(&kind, &attributes, get_span(node, source))?;

    // Convert inline_state_variants from HashMap<WidgetState, HashMap<String, AttributeValue>>
    // to HashMap<WidgetState, StyleProperties>
    let mut final_state_variants: HashMap<WidgetState, StyleProperties> = HashMap::new();
    for (state, state_attrs) in inline_state_variants {
        if let Some(state_style) = parse_style_attributes(&state_attrs).map_err(|e| ParseError {
            kind: ParseErrorKind::InvalidValue,
            message: format!("Invalid style in {:?} state: {}", state, e),
            span: get_span(node, source),
            suggestion: None,
        })? {
            final_state_variants.insert(state, state_style);
        }
    }

    Ok(WidgetNode {
        kind,
        id,
        attributes,
        events,
        children,
        span: get_span(node, source),
        style,
        layout,
        theme_ref,
        classes,
        breakpoint_attributes,
        inline_state_variants: final_state_variants,
    })
}

/// Parse a `<dampen>` document with themes and widgets
fn parse_dampen_document(root: Node, source: &str) -> Result<DampenDocument, ParseError> {
    let mut themes = HashMap::new();
    let mut style_classes = HashMap::new();
    let mut root_widget = None;
    let mut global_theme = None;
    let mut follow_system = true;

    // Parse version attribute from <dampen> root element
    let span = get_span(root, source);
    let version = if let Some(version_attr) = root.attribute("version") {
        let parsed = parse_version_string(version_attr, span)?;
        validate_version_supported(&parsed, span)?;
        parsed
    } else {
        // Default to version 1.0 for backward compatibility
        SchemaVersion::default()
    };

    // Iterate through children of <dampen>
    for child in root.children() {
        if child.node_type() != NodeType::Element {
            continue;
        }

        let tag_name = child.tag_name().name();

        match tag_name {
            "themes" => {
                // Parse themes section
                for theme_node in child.children() {
                    if theme_node.node_type() == NodeType::Element
                        && theme_node.tag_name().name() == "theme"
                    {
                        let theme =
                            crate::parser::theme_parser::parse_theme_from_node(theme_node, source)?;
                        let name = theme_node
                            .attribute("name")
                            .map(|s| s.to_string())
                            .unwrap_or_else(|| "default".to_string());
                        themes.insert(name, theme);
                    }
                }
            }
            "style_classes" | "classes" | "styles" => {
                // Parse style classes
                for class_node in child.children() {
                    if class_node.node_type() == NodeType::Element {
                        let tag = class_node.tag_name().name();
                        if tag == "class" || tag == "style" {
                            let class = crate::parser::theme_parser::parse_style_class_from_node(
                                class_node, source,
                            )?;
                            style_classes.insert(class.name.clone(), class);
                        }
                    }
                }
            }
            "global_theme" | "default_theme" => {
                // Set global theme reference
                if let Some(theme_name) = child.attribute("name") {
                    global_theme = Some(theme_name.to_string());
                }
            }
            "follow_system" => {
                if let Some(enabled) = child.attribute("enabled") {
                    follow_system = enabled.parse::<bool>().unwrap_or(true);
                }
            }
            _ => {
                // This should be a widget - parse as root
                if root_widget.is_some() {
                    return Err(ParseError {
                        kind: ParseErrorKind::XmlSyntax,
                        message: "Multiple root widgets found in <dampen>".to_string(),
                        span: get_span(child, source),
                        suggestion: Some("Only one root widget is allowed".to_string()),
                    });
                }
                root_widget = Some(parse_node(child, source)?);
            }
        }
    }

    // Ensure we have a root widget, or provide a default if themes are present
    let root_widget = if let Some(w) = root_widget {
        w
    } else if !themes.is_empty() || !style_classes.is_empty() {
        // Create an empty default container if this is a theme/style-only file
        WidgetNode::default()
    } else {
        return Err(ParseError {
            kind: ParseErrorKind::XmlSyntax,
            message: "No root widget found in <dampen>".to_string(),
            span: get_span(root, source),
            suggestion: Some("Add a widget like <column> or <row> inside <dampen>".to_string()),
        });
    };

    // T098: Enforce strict version validation
    // Widgets requiring a newer schema version than declared must be rejected
    validate_widget_versions_strict(&root_widget, &version)?;

    // Enforce nesting constraints (e.g. DataColumn must be inside DataTable)
    validate_nesting_constraints(&root_widget, None)?;

    Ok(DampenDocument {
        version,
        root: root_widget,
        themes,
        style_classes,
        global_theme,
        follow_system,
    })
}

/// Recursively validate widget nesting constraints
fn validate_nesting_constraints(
    node: &WidgetNode,
    parent_kind: Option<&WidgetKind>,
) -> Result<(), ParseError> {
    // Rule: DataColumn must be inside DataTable
    if node.kind == WidgetKind::DataColumn && parent_kind != Some(&WidgetKind::DataTable) {
        return Err(ParseError {
            kind: ParseErrorKind::InvalidChild,
            message: "DataColumn must be a direct child of DataTable".to_string(),
            span: node.span,
            suggestion: Some("Wrap this column in a <data_table>".to_string()),
        });
    }

    // Rule: Tab must be inside TabBar
    if node.kind == WidgetKind::Tab && parent_kind != Some(&WidgetKind::TabBar) {
        return Err(ParseError {
            kind: ParseErrorKind::InvalidChild,
            message: "Tab must be inside TabBar".to_string(),
            span: node.span,
            suggestion: Some("Wrap this tab in a <tab_bar>".to_string()),
        });
    }

    // Rule: TabBar must contain only Tab children
    if node.kind == WidgetKind::TabBar {
        for child in &node.children {
            if child.kind != WidgetKind::Tab {
                return Err(ParseError {
                    kind: ParseErrorKind::InvalidChild,
                    message: "TabBar can only contain Tab widgets".to_string(),
                    span: child.span,
                    suggestion: Some("Use <tab> elements inside <tab_bar>".to_string()),
                });
            }
        }
    }

    // Recurse
    for child in &node.children {
        validate_nesting_constraints(child, Some(&node.kind))?;
    }

    Ok(())
}

/// Recursively validate widget versions and return an error on mismatch.
fn validate_widget_versions_strict(
    node: &WidgetNode,
    doc_version: &SchemaVersion,
) -> Result<(), ParseError> {
    let min_version = node.kind.minimum_version();

    if (min_version.major, min_version.minor) > (doc_version.major, doc_version.minor) {
        return Err(ParseError {
            kind: ParseErrorKind::UnsupportedVersion,
            message: format!(
                "Widget '{}' requires schema v{}.{} but document declares v{}.{}",
                node.kind,
                min_version.major,
                min_version.minor,
                doc_version.major,
                doc_version.minor
            ),
            span: node.span,
            suggestion: Some(format!(
                "Update to <dampen version=\"{}.{}\"> or remove this widget",
                min_version.major, min_version.minor
            )),
        });
    }

    for child in &node.children {
        validate_widget_versions_strict(child, doc_version)?;
    }

    Ok(())
}

/// Parse comma-separated list into `Vec<String>`
pub fn parse_comma_separated(value: &str) -> Vec<String> {
    value
        .split(',')
        .map(|s| s.trim().to_string())
        .filter(|s| !s.is_empty())
        .collect()
}

/// Parse a simple enum value (case-insensitive) and return the matched variant
pub fn parse_enum_value<T>(value: &str, valid_variants: &[&str]) -> Result<T, String>
where
    T: std::str::FromStr + std::fmt::Display,
{
    let normalized = value.trim().to_lowercase();
    for variant in valid_variants.iter() {
        if variant.to_lowercase() == normalized {
            return T::from_str(variant).map_err(|_| {
                format!(
                    "Failed to parse '{}' as {}",
                    variant,
                    std::any::type_name::<T>()
                )
            });
        }
    }
    Err(format!(
        "Invalid value '{}'. Valid options: {}",
        value,
        valid_variants.join(", ")
    ))
}

/// Parse attribute value, detecting binding expressions
fn parse_attribute_value(value: &str, span: Span) -> Result<AttributeValue, ParseError> {
    // Check if value contains binding syntax {expr}
    if value.contains('{') && value.contains('}') {
        // Parse interpolated parts
        let mut parts = Vec::new();
        let mut remaining = value;

        while let Some(start_pos) = remaining.find('{') {
            // Add literal before {
            if start_pos > 0 {
                parts.push(InterpolatedPart::Literal(
                    remaining[..start_pos].to_string(),
                ));
            }

            // Find closing }
            if let Some(end_pos) = remaining[start_pos..].find('}') {
                let expr_start = start_pos + 1;
                let expr_end = start_pos + end_pos;
                let expr_str = &remaining[expr_start..expr_end];

                // Parse the expression
                let binding_expr = tokenize_binding_expr(
                    expr_str,
                    span.start + expr_start,
                    span.line,
                    span.column + expr_start as u32,
                )
                .map_err(|e| ParseError {
                    kind: ParseErrorKind::InvalidExpression,
                    message: format!("Invalid expression: {}", e),
                    span: Span::new(
                        span.start + expr_start,
                        span.start + expr_end,
                        span.line,
                        span.column + expr_start as u32,
                    ),
                    suggestion: None,
                })?;

                parts.push(InterpolatedPart::Binding(binding_expr));

                // Move past the }
                remaining = &remaining[expr_end + 1..];
            } else {
                // No closing }, treat rest as literal
                parts.push(InterpolatedPart::Literal(remaining.to_string()));
                break;
            }
        }

        // Add remaining literal
        if !remaining.is_empty() {
            parts.push(InterpolatedPart::Literal(remaining.to_string()));
        }

        // If only one binding with no literals, return Binding
        // If multiple parts, return Interpolated
        if parts.len() == 1 {
            match &parts[0] {
                InterpolatedPart::Binding(expr) => {
                    return Ok(AttributeValue::Binding(expr.clone()));
                }
                InterpolatedPart::Literal(lit) => {
                    return Ok(AttributeValue::Static(lit.clone()));
                }
            }
        } else {
            return Ok(AttributeValue::Interpolated(parts));
        }
    }

    // Static value
    Ok(AttributeValue::Static(value.to_string()))
}

/// Extract span information from roxmltree node
fn get_span(node: Node, source: &str) -> Span {
    let range = node.range();

    // Calculate line and column from byte offset
    let (line, col) = calculate_line_col(source, range.start);

    Span {
        start: range.start,
        end: range.end,
        line,
        column: col,
    }
}

/// Calculate line and column from byte offset
///
/// Optimized to stop early once the target offset is reached.
fn calculate_line_col(source: &str, offset: usize) -> (u32, u32) {
    if offset == 0 {
        return (1, 1);
    }

    let mut line = 1;
    let mut col = 1;

    for (i, c) in source.char_indices().take(offset.saturating_add(1)) {
        if i >= offset {
            break;
        }
        if c == '\n' {
            line += 1;
            col = 1;
        } else {
            col += 1;
        }
    }

    (line, col)
}

/// Parse layout-related attributes from the attributes map
fn parse_layout_attributes(
    kind: &WidgetKind,
    attributes: &HashMap<String, AttributeValue>,
) -> Result<Option<crate::ir::layout::LayoutConstraints>, String> {
    use crate::ir::layout::LayoutConstraints;
    use crate::parser::style_parser::{
        parse_alignment, parse_constraint, parse_float_attr, parse_int_attr, parse_justification,
        parse_length_attr, parse_padding_attr, parse_spacing,
    };

    let mut layout = LayoutConstraints::default();
    let mut has_any = false;

    // Parse width
    if let Some(AttributeValue::Static(value)) = attributes.get("width") {
        layout.width = Some(parse_length_attr(value)?);
        has_any = true;
    }

    // Parse height
    if let Some(AttributeValue::Static(value)) = attributes.get("height") {
        layout.height = Some(parse_length_attr(value)?);
        has_any = true;
    }

    // Parse min/max constraints
    if let Some(AttributeValue::Static(value)) = attributes.get("min_width") {
        layout.min_width = Some(parse_constraint(value)?);
        has_any = true;
    }

    if let Some(AttributeValue::Static(value)) = attributes.get("max_width") {
        layout.max_width = Some(parse_constraint(value)?);
        has_any = true;
    }

    if let Some(AttributeValue::Static(value)) = attributes.get("min_height") {
        layout.min_height = Some(parse_constraint(value)?);
        has_any = true;
    }

    if let Some(AttributeValue::Static(value)) = attributes.get("max_height") {
        layout.max_height = Some(parse_constraint(value)?);
        has_any = true;
    }

    // Parse padding
    if let Some(AttributeValue::Static(value)) = attributes.get("padding") {
        layout.padding = Some(parse_padding_attr(value)?);
        has_any = true;
    }

    // Parse spacing
    if let Some(AttributeValue::Static(value)) = attributes.get("spacing") {
        layout.spacing = Some(parse_spacing(value)?);
        has_any = true;
    }

    // Parse alignment
    if let Some(AttributeValue::Static(value)) = attributes.get("align_items") {
        layout.align_items = Some(parse_alignment(value)?);
        has_any = true;
    }

    if let Some(AttributeValue::Static(value)) = attributes.get("justify_content") {
        layout.justify_content = Some(parse_justification(value)?);
        has_any = true;
    }

    if let Some(AttributeValue::Static(value)) = attributes.get("align_self") {
        layout.align_self = Some(parse_alignment(value)?);
        has_any = true;
    }

    // Parse direct alignment (align_x, align_y)
    if let Some(AttributeValue::Static(value)) = attributes.get("align_x") {
        layout.align_x = Some(parse_alignment(value)?);
        has_any = true;
    }

    if let Some(AttributeValue::Static(value)) = attributes.get("align_y") {
        layout.align_y = Some(parse_alignment(value)?);
        has_any = true;
    }

    // Parse align shorthand (sets both align_items and justify_content)
    if let Some(AttributeValue::Static(value)) = attributes.get("align") {
        let alignment = parse_alignment(value)?;
        layout.align_items = Some(alignment);
        layout.justify_content = Some(match alignment {
            crate::ir::layout::Alignment::Start => crate::ir::layout::Justification::Start,
            crate::ir::layout::Alignment::Center => crate::ir::layout::Justification::Center,
            crate::ir::layout::Alignment::End => crate::ir::layout::Justification::End,
            crate::ir::layout::Alignment::Stretch => crate::ir::layout::Justification::Center,
        });
        has_any = true;
    }

    // Parse direction
    if let Some(AttributeValue::Static(value)) = attributes.get("direction") {
        layout.direction = Some(crate::ir::layout::Direction::parse(value)?);
        has_any = true;
    }

    // Parse position (skip for Tooltip - it has its own position attribute)
    if !matches!(kind, WidgetKind::Tooltip)
        && let Some(AttributeValue::Static(value)) = attributes.get("position")
    {
        layout.position = Some(crate::ir::layout::Position::parse(value)?);
        has_any = true;
    }

    // Parse position offsets
    if let Some(AttributeValue::Static(value)) = attributes.get("top") {
        layout.top = Some(parse_float_attr(value, "top")?);
        has_any = true;
    }

    if let Some(AttributeValue::Static(value)) = attributes.get("right") {
        layout.right = Some(parse_float_attr(value, "right")?);
        has_any = true;
    }

    if let Some(AttributeValue::Static(value)) = attributes.get("bottom") {
        layout.bottom = Some(parse_float_attr(value, "bottom")?);
        has_any = true;
    }

    if let Some(AttributeValue::Static(value)) = attributes.get("left") {
        layout.left = Some(parse_float_attr(value, "left")?);
        has_any = true;
    }

    // Parse z-index
    if let Some(AttributeValue::Static(value)) = attributes.get("z_index") {
        layout.z_index = Some(parse_int_attr(value, "z_index")?);
        has_any = true;
    }

    // Validate the layout
    if has_any {
        layout
            .validate()
            .map_err(|e| format!("Layout validation failed: {}", e))?;
        Ok(Some(layout))
    } else {
        Ok(None)
    }
}

/// Parse style-related attributes from the attributes map
fn parse_style_attributes(
    attributes: &HashMap<String, AttributeValue>,
) -> Result<Option<crate::ir::style::StyleProperties>, String> {
    use crate::parser::style_parser::{
        build_border, build_style_properties, parse_background_attr, parse_border_color,
        parse_border_radius, parse_border_style, parse_border_width, parse_color_attr,
        parse_opacity, parse_shadow_attr, parse_transform,
    };

    let mut background = None;
    let mut color = None;
    let mut border_width = None;
    let mut border_color = None;
    let mut border_radius = None;
    let mut border_style = None;
    let mut shadow = None;
    let mut opacity = None;
    let mut transform = None;
    let mut has_any = false;

    // Parse background
    if let Some(AttributeValue::Static(value)) = attributes.get("background") {
        background = Some(parse_background_attr(value)?);
        has_any = true;
    }

    // Parse color
    if let Some(AttributeValue::Static(value)) = attributes.get("color") {
        color = Some(parse_color_attr(value)?);
        has_any = true;
    }

    // Parse border attributes
    if let Some(AttributeValue::Static(value)) = attributes.get("border_width") {
        border_width = Some(parse_border_width(value)?);
        has_any = true;
    }

    if let Some(AttributeValue::Static(value)) = attributes.get("border_color") {
        border_color = Some(parse_border_color(value)?);
        has_any = true;
    }

    if let Some(AttributeValue::Static(value)) = attributes.get("border_radius") {
        border_radius = Some(parse_border_radius(value)?);
        has_any = true;
    }

    if let Some(AttributeValue::Static(value)) = attributes.get("border_style") {
        border_style = Some(parse_border_style(value)?);
        has_any = true;
    }

    // Parse shadow
    if let Some(AttributeValue::Static(value)) = attributes.get("shadow") {
        shadow = Some(parse_shadow_attr(value)?);
        has_any = true;
    }

    // Parse opacity
    if let Some(AttributeValue::Static(value)) = attributes.get("opacity") {
        opacity = Some(parse_opacity(value)?);
        has_any = true;
    }

    // Parse transform
    if let Some(AttributeValue::Static(value)) = attributes.get("transform") {
        transform = Some(parse_transform(value)?);
        has_any = true;
    }

    if has_any {
        let border = build_border(border_width, border_color, border_radius, border_style)?;
        let style = build_style_properties(background, color, border, shadow, opacity, transform)?;
        Ok(Some(style))
    } else {
        Ok(None)
    }
}

/// Validates that there are no circular dependencies in UI file includes.
///
/// **Feature T125 - Not Yet Implemented**
///
/// Currently, Dampen does not support file includes/imports in XML.
/// This function is a placeholder that will be implemented when UI file
/// composition is added.
///
/// # Returns
///
/// Currently returns `Ok(())` since includes are not supported.
/// Once implemented, returns `Err(ParseError)` for circular dependencies.
pub fn validate_no_circular_dependencies(
    _file_path: &std::path::Path,
    _visited: &mut std::collections::HashSet<std::path::PathBuf>,
) -> Result<(), ParseError> {
    Ok(())
}

#[cfg(test)]
mod circular_dependency_tests {
    use super::*;
    use std::collections::HashSet;
    use std::path::PathBuf;

    #[test]
    fn test_no_circular_dependencies_without_includes() {
        // T125: Validate that single files have no circular dependencies
        let file_path = PathBuf::from("test.dampen");
        let mut visited = HashSet::new();

        let result = validate_no_circular_dependencies(&file_path, &mut visited);
        assert!(
            result.is_ok(),
            "Single file should have no circular dependencies"
        );
    }

    // Future tests when includes are supported:
    // - test_detect_simple_circular_dependency: A -> B -> A
    // - test_detect_complex_circular_dependency: A -> B -> C -> D -> B
    // - test_allow_diamond_dependencies: A->B, A->C, B->D, C->D (this is OK, not circular)
    // - test_self_include_rejected: A -> A
}

#[cfg(test)]
mod inline_state_styles_tests {
    use super::*;
    use crate::ir::theme::WidgetState;

    #[test]
    fn test_parse_single_state_attribute() {
        // T011: Parse button with single hover:background state attribute
        // Note: XML requires namespace declaration for colons in attribute names
        let xml = r##"
            <dampen version="1.0" xmlns:hover="urn:dampen:state:hover">
                <button label="Click" hover:background="#ff0000" />
            </dampen>
        "##;

        let result = parse(xml);
        assert!(result.is_ok(), "Should parse valid XML with hover state");

        let doc = result.unwrap();
        let button = &doc.root;

        // Verify inline_state_variants contains hover state
        assert!(
            button
                .inline_state_variants
                .contains_key(&WidgetState::Hover),
            "Should have hover state variant"
        );

        let hover_style = button
            .inline_state_variants
            .get(&WidgetState::Hover)
            .unwrap();

        // Verify hover background color is red
        assert!(
            hover_style.background.is_some(),
            "Hover state should have background"
        );
    }

    #[test]
    fn test_parse_multiple_state_attributes() {
        // T012: Parse button with multiple state attributes
        // Note: Each state needs its own unique namespace URI to avoid attribute conflicts
        let xml = r##"
            <dampen version="1.0"
                xmlns:hover="urn:dampen:state:hover"
                xmlns:active="urn:dampen:state:active"
                xmlns:disabled="urn:dampen:state:disabled">
                <button
                    label="Click"
                    hover:background="#ff0000"
                    active:background="#00ff00"
                    disabled:opacity="0.5"
                />
            </dampen>
        "##;

        let result = parse(xml);
        assert!(
            result.is_ok(),
            "Should parse valid XML with multiple states"
        );

        let doc = result.unwrap();
        let button = &doc.root;

        // Verify all three state variants exist
        assert!(
            button
                .inline_state_variants
                .contains_key(&WidgetState::Hover),
            "Should have hover state"
        );
        assert!(
            button
                .inline_state_variants
                .contains_key(&WidgetState::Active),
            "Should have active state"
        );
        assert!(
            button
                .inline_state_variants
                .contains_key(&WidgetState::Disabled),
            "Should have disabled state"
        );

        // Verify hover has background
        let hover_style = button
            .inline_state_variants
            .get(&WidgetState::Hover)
            .unwrap();
        assert!(
            hover_style.background.is_some(),
            "Hover state should have background"
        );

        // Verify active has background
        let active_style = button
            .inline_state_variants
            .get(&WidgetState::Active)
            .unwrap();
        assert!(
            active_style.background.is_some(),
            "Active state should have background"
        );

        // Verify disabled has opacity
        let disabled_style = button
            .inline_state_variants
            .get(&WidgetState::Disabled)
            .unwrap();
        assert!(
            disabled_style.opacity.is_some(),
            "Disabled state should have opacity"
        );
    }

    #[test]
    fn test_parse_invalid_state_prefix() {
        // T013: Parse button with invalid state prefix should treat as regular attribute
        let xml = r##"
            <dampen version="1.0" xmlns:unknown="urn:dampen:state:unknown">
                <button label="Click" unknown:background="#ff0000" />
            </dampen>
        "##;

        let result = parse(xml);
        assert!(
            result.is_ok(),
            "Should parse with warning for invalid state"
        );

        let doc = result.unwrap();
        let button = &doc.root;

        // Verify inline_state_variants is empty (invalid prefix ignored)
        assert!(
            button.inline_state_variants.is_empty(),
            "Should have no state variants for invalid prefix"
        );

        // Verify unknown:background is treated as regular attribute
        assert!(
            button.attributes.contains_key("unknown:background"),
            "Invalid state prefix should be treated as regular attribute"
        );
    }
}