seam-skeleton 0.5.27

/* src/cli/skeleton/src/extract/array.rs */

use std::collections::HashSet;

use super::boolean::insert_boolean_directives;
use super::combo::AxisGroup;
use super::container::{hoist_list_container, unwrap_container_tree};
use super::directives::{comment_each, comment_else, comment_endeach, comment_endif, comment_if};
use super::dom::{DomNode, parse_html, serialize};
use super::tree_diff::{DiffOp, diff_children};
use super::variant::{find_pair_for_axis, find_scoped_variant_indices};
use super::{
	Axis, content_indices, extract_template_inner, navigate_to_children, nth_content_index,
	rename_slot_markers,
};

/// Process a single array axis (without nested children):
/// insert each/endeach directives, rename slot markers, unwrap container.
pub(super) fn process_array(
	result: Vec<DomNode>,
	axes: &[Axis],
	variants: &[String],
	axis_idx: usize,
) -> Vec<DomNode> {
	let axis = &axes[axis_idx];
	let pair = find_pair_for_axis(axes, variants.len(), axis_idx);
	let Some((vi_pop, vi_empty)) = pair else {
		return result;
	};

	let tree_pop = parse_html(&variants[vi_pop]);
	let tree_empty = parse_html(&variants[vi_empty]);

	insert_array_directives(result, &tree_pop, &tree_empty, &axis.path)
}

/// Insert array directives (each/endeach) by comparing populated vs empty trees.
fn insert_array_directives(
	tree: Vec<DomNode>,
	pop_nodes: &[DomNode],
	empty_nodes: &[DomNode],
	path: &str,
) -> Vec<DomNode> {
	let ops = diff_children(pop_nodes, empty_nodes);

	// Collect body nodes (OnlyLeft in populated) and replacement nodes (OnlyRight in empty)
	let mut body_indices: Vec<usize> = Vec::new();
	let mut has_only_right = false;
	let mut has_modified = false;

	for op in &ops {
		match op {
			DiffOp::OnlyLeft(ai) => body_indices.push(*ai),
			DiffOp::OnlyRight(_) => has_only_right = true,
			DiffOp::Modified(_, _) => has_modified = true,
			DiffOp::Identical(_, _) => {}
		}
	}

	// If content only differs inside a shared element, recurse
	if body_indices.is_empty() && has_modified {
		return insert_array_modified(tree, pop_nodes, empty_nodes, path);
	}

	// If there's only a replacement (OnlyLeft + OnlyRight at same position), treat
	// the entire region as a conditional with if/else semantics for the array
	if body_indices.is_empty() && has_only_right {
		// Fall back to treating as boolean-like diff
		return insert_boolean_directives(&tree, pop_nodes, empty_nodes, path);
	}

	if body_indices.is_empty() {
		return tree;
	}

	// Extract body nodes and rename slot markers
	let mut body: Vec<DomNode> = body_indices.iter().map(|&i| pop_nodes[i].clone()).collect();
	rename_slot_markers(&mut body, path);

	// Container unwrap + each/endeach wrapping
	let each_nodes = wrap_array_body(&body, path);

	// If empty variant has replacement content, wrap each in if/else
	let final_nodes = if has_only_right {
		let fallback: Vec<DomNode> = ops
			.iter()
			.filter_map(|op| match op {
				DiffOp::OnlyRight(bi) => Some(empty_nodes[*bi].clone()),
				_ => None,
			})
			.collect();

		let mut nodes = vec![comment_if(path)];
		nodes.extend(each_nodes);
		nodes.push(comment_else());
		nodes.extend(fallback);
		nodes.push(comment_endif(path));
		nodes
	} else {
		each_nodes
	};

	// Build result: copy content map approach
	let content_map = content_indices(&tree);

	let mut result = Vec::new();
	let mut tree_content_idx = 0usize;
	let mut tree_pos = 0usize;

	for op in &ops {
		// Copy leading directives
		let target =
			if tree_content_idx < content_map.len() { content_map[tree_content_idx] } else { tree.len() };
		while tree_pos < target {
			result.push(tree[tree_pos].clone());
			tree_pos += 1;
		}

		match op {
			DiffOp::Identical(_, _) => {
				result.push(tree[tree_pos].clone());
				tree_pos += 1;
				tree_content_idx += 1;
			}
			DiffOp::OnlyLeft(ai) => {
				// First body node gets the final_nodes, rest are consumed
				if *ai == body_indices[0] {
					result.extend(final_nodes.iter().cloned());
				}
				tree_pos += 1;
				tree_content_idx += 1;
			}
			DiffOp::OnlyRight(_) => {
				// Empty variant's extra content — skip (replaced by array when populated)
			}
			DiffOp::Modified(_, _) => {
				result.push(tree[tree_pos].clone());
				tree_pos += 1;
				tree_content_idx += 1;
			}
		}
	}

	while tree_pos < tree.len() {
		result.push(tree[tree_pos].clone());
		tree_pos += 1;
	}

	result
}

/// Handle array where the diff is inside a shared parent element (Modified case).
fn insert_array_modified(
	mut tree: Vec<DomNode>,
	pop_nodes: &[DomNode],
	empty_nodes: &[DomNode],
	path: &str,
) -> Vec<DomNode> {
	let ops = diff_children(pop_nodes, empty_nodes);
	for op in ops {
		if let DiffOp::Modified(ai, bi) = op
			&& let (DomNode::Element { children: pc, .. }, DomNode::Element { children: ec, .. }) =
				(&pop_nodes[ai], &empty_nodes[bi])
		{
			// Find corresponding tree node (skip directive comments)
			if let Some(ti) = nth_content_index(&tree, ai)
				&& let DomNode::Element { children: tc, .. } = &mut tree[ti]
			{
				*tc = insert_array_directives(std::mem::take(tc), pc, ec, path);
			}
		}
	}
	tree
}

/// Wrap array body nodes with each/endeach, unwrapping container if applicable.
fn wrap_array_body(body: &[DomNode], path: &str) -> Vec<DomNode> {
	// Simple case: single list container
	if let Some((tag, attrs, inner)) = unwrap_container_tree(body) {
		let mut inner_with_directives = vec![comment_each(path)];
		inner_with_directives.extend(inner.iter().cloned());
		inner_with_directives.push(comment_endeach());
		return vec![DomNode::Element {
			tag: tag.to_string(),
			attrs: attrs.to_string(),
			children: inner_with_directives,
			self_closing: false,
		}];
	}

	// Hoist case: directive comments wrap identical list containers
	if let Some((tag, attrs, inner)) = hoist_list_container(body) {
		let mut inner_with_directives = vec![comment_each(path)];
		inner_with_directives.extend(inner);
		inner_with_directives.push(comment_endeach());
		return vec![DomNode::Element {
			tag: tag.clone(),
			attrs: attrs.clone(),
			children: inner_with_directives,
			self_closing: false,
		}];
	}

	// No container unwrap
	let mut nodes = vec![comment_each(path)];
	nodes.extend(body.iter().cloned());
	nodes.push(comment_endeach());
	nodes
}

/// Recursively find the body location by diffing populated vs empty trees.
/// Traverses through Modified elements until OnlyLeft items (the body) are found.
struct BodyLocation {
	path: Vec<usize>,
	body_indices: Vec<usize>,
	fallback_indices: Vec<usize>,
}

fn find_body_in_trees(pop: &[DomNode], empty: &[DomNode]) -> Option<BodyLocation> {
	let ops = diff_children(pop, empty);

	let body_idx: Vec<usize> = ops
		.iter()
		.filter_map(|op| if let DiffOp::OnlyLeft(ai) = op { Some(*ai) } else { None })
		.collect();

	if !body_idx.is_empty() {
		let fallback_idx: Vec<usize> = ops
			.iter()
			.filter_map(|op| if let DiffOp::OnlyRight(bi) = op { Some(*bi) } else { None })
			.collect();
		return Some(BodyLocation {
			path: vec![],
			body_indices: body_idx,
			fallback_indices: fallback_idx,
		});
	}

	// Recurse into Modified elements to find body deeper
	for op in &ops {
		if let DiffOp::Modified(ai, bi) = op
			&& let (DomNode::Element { children: pc, .. }, DomNode::Element { children: ec, .. }) =
				(&pop[*ai], &empty[*bi])
			&& let Some(mut loc) = find_body_in_trees(pc, ec)
		{
			loc.path.insert(0, *ai);
			return Some(loc);
		}
	}

	None
}

/// Navigate into a tree at a path and replace the body nodes with replacement.
fn replace_body_at_path(
	result: &mut Vec<DomNode>,
	path: &[usize],
	body_indices: &[usize],
	replacement: Vec<DomNode>,
) {
	if path.is_empty() {
		let body_set: HashSet<usize> = body_indices.iter().copied().collect();
		let mut new = Vec::new();
		for (i, node) in result.iter().enumerate() {
			if body_set.contains(&i) {
				if i == body_indices[0] {
					new.extend(replacement.iter().cloned());
				}
			} else {
				new.push(node.clone());
			}
		}
		*result = new;
	} else {
		// Navigate to the content node at index path[0] (skip directive comments)
		if let Some(ci) = nth_content_index(result, path[0])
			&& let DomNode::Element { children, .. } = &mut result[ci]
		{
			replace_body_at_path(children, &path[1..], body_indices, replacement);
		}
	}
}

/// Process an array axis that has nested child axes.
pub(super) fn process_array_with_children(
	mut result: Vec<DomNode>,
	axes: &[Axis],
	variants: &[String],
	group: &AxisGroup,
) -> Vec<DomNode> {
	let array_axis = &axes[group.parent_axis_idx];
	if array_axis.kind != "array" {
		return result;
	}

	// 1. Find populated/empty pair
	let pair = find_pair_for_axis(axes, variants.len(), group.parent_axis_idx);
	let Some((_, vi_empty)) = pair else {
		return result;
	};
	let tree_empty = parse_html(&variants[vi_empty]);

	// 2. Find all scoped variants (array=populated, non-child axes at reference)
	let scoped_indices =
		find_scoped_variant_indices(axes, variants.len(), group.parent_axis_idx, &group.children);
	if scoped_indices.is_empty() {
		return result;
	}

	// 3. Parse all scoped variants
	let scoped_trees: Vec<Vec<DomNode>> =
		scoped_indices.iter().map(|&i| parse_html(&variants[i])).collect();
	let first_pop = &scoped_trees[0];

	// 4. Find body location by recursively traversing Modified elements
	let Some(body_loc) = find_body_in_trees(first_pop, &tree_empty) else {
		return result;
	};

	// 5. Extract body from each scoped variant at the found path
	let body_variants: Vec<String> = scoped_trees
		.iter()
		.map(|tree| {
			let parent = navigate_to_children(tree, &body_loc.path);
			let body_nodes: Vec<DomNode> = body_loc
				.body_indices
				.iter()
				.filter(|&&i| i < parent.len())
				.map(|&i| parent[i].clone())
				.collect();
			serialize(&body_nodes)
		})
		.collect();

	// 6. Build child axes with stripped parent prefix
	let parent_dot = format!("{}.", array_axis.path);
	let child_axes: Vec<Axis> = group
		.children
		.iter()
		.map(|&i| {
			let orig = &axes[i];
			Axis {
				path: orig.path.strip_prefix(&parent_dot).unwrap_or(&orig.path).to_string(),
				kind: orig.kind.clone(),
				values: orig.values.clone(),
			}
		})
		.collect();

	// 6b. Pre-rename slot markers in body variants
	let slot_prefix = format!("<!--seam:{}.", array_axis.path);
	let body_variants: Vec<String> =
		body_variants.into_iter().map(|b| b.replace(&slot_prefix, "<!--seam:")).collect();

	// 7. Recursively extract template from body variants
	let template_body = extract_template_inner(&child_axes, &body_variants);
	let mut body_tree = parse_html(&template_body);
	rename_slot_markers(&mut body_tree, &array_axis.path);

	// 8. Wrap with each markers, adding if/else fallback when present
	let each_nodes = wrap_array_body(&body_tree, &array_axis.path);

	let final_nodes = if !body_loc.fallback_indices.is_empty() {
		let empty_children = navigate_to_children(&tree_empty, &body_loc.path);
		let fallback: Vec<DomNode> = body_loc
			.fallback_indices
			.iter()
			.filter(|&&i| i < empty_children.len())
			.map(|&i| empty_children[i].clone())
			.collect();

		let mut nodes = vec![comment_if(&array_axis.path)];
		nodes.extend(each_nodes);
		nodes.push(comment_else());
		nodes.extend(fallback);
		nodes.push(comment_endif(&array_axis.path));
		nodes
	} else {
		each_nodes
	};

	// 9. Insert into result tree at the body location
	replace_body_at_path(&mut result, &body_loc.path, &body_loc.body_indices, final_nodes);
	result
}