feat: implement interactable dap hover

lua/ow/dap/hover/tree.lua

@@ -0,0 +1,156 @@
+-- Tree-based DAP variable formatter with expand/collapse support
+local Content = require("ow.dap.hover.content")
+local Node = require("ow.dap.hover.node")
+local log = require("ow.log")
+
+---@class ow.dap.hover.Tree
+---@field session dap.Session
+---@field root_node ow.dap.hover.Node?
+---@field line_to_node table<integer, ow.dap.hover.Node> Map line numbers to nodes
+---@field extmark_to_node table<integer, ow.dap.hover.Node> Map extmark IDs to nodes
+local Tree = {}
+Tree.__index = Tree
+
+---Create a new tree formatter
+---@param session dap.Session
+---@return ow.dap.hover.Tree
+function Tree.new(session)
+    return setmetatable({
+        session = session,
+        root_node = nil,
+        line_to_node = {},
+        extmark_to_node = {},
+    }, Tree)
+end
+
+---Build the tree from a DAP item (async)
+---@async
+---@param item ow.dap.Item Root item to build tree from
+---@return ow.dap.hover.Node
+function Tree:build(item)
+    local root = Node.new(item, nil)
+    self.root_node = root
+
+    -- For now, start with everything collapsed
+    -- Later we can add logic to expand first level by default
+    return root
+end
+
+---Load children for a node (async)
+---@async
+---@param node ow.dap.hover.Node
+---@return boolean success Whether loading succeeded
+function Tree:load_children(node)
+    if not node:is_container() or #node.children > 0 then
+        return true -- Already loaded or not a container
+    end
+
+    local err, resp = self.session:request("variables", {
+        variablesReference = node.item.variablesReference,
+    })
+
+    if err or not resp or #resp.variables == 0 then
+        return false
+    end
+
+    -- Create child nodes
+    for i, var in ipairs(resp.variables) do
+        local child_item = {
+            name = var.name,
+            type = var.type,
+            value = var.value,
+            variablesReference = var.variablesReference,
+            depth = node.item.depth + 1,
+        }
+
+        local child = Node.new(child_item, node)
+        child.is_last_child = (i == #resp.variables)
+
+        -- Format array indices properly
+        if child_item.name:match("^%d+$") then
+            child_item.name = "[" .. child_item.name .. "]"
+        end
+
+        table.insert(node.children, child)
+    end
+
+    return true
+end
+
+---Render the tree to highlighted content
+---@async
+---@return ow.dap.hover.Content
+function Tree:render()
+    if not self.root_node then
+        return Content.new()
+    end
+
+    local content = Content.new()
+    self.line_to_node = {}
+
+    self:render_node(self.root_node, content, 0)
+    return content
+end
+
+---Render a single node and its expanded children
+---@async
+---@param node ow.dap.hover.Node
+---@param content ow.dap.hover.Content
+---@param line_number integer Current line number
+---@return integer new_line_number Updated line number after rendering
+function Tree:render_node(node, content, line_number)
+    -- Store line mapping
+    node.line_number = line_number
+    self.line_to_node[line_number] = node
+
+    -- Format this node
+    local node_content = node:format(self.session)
+    content.text = content.text .. node_content.text
+
+    -- Copy highlights, adjusting for current position
+    local text_offset = #content.text - #node_content.text
+    for _, highlight in ipairs(node_content.highlights) do
+        table.insert(content.highlights, {
+            group = highlight.group,
+            start_col = highlight.start_col + text_offset,
+            end_col = highlight.end_col + text_offset,
+        })
+    end
+
+    content:newline()
+    line_number = line_number + 1
+
+    -- Render expanded children
+    if node.is_expanded then
+        for _, child in ipairs(node.children) do
+            line_number = self:render_node(child, content, line_number)
+        end
+    end
+
+    return line_number
+end
+
+---Toggle expansion state of node at given line
+---@async
+---@param line_number integer
+---@return boolean success Whether toggle succeeded
+function Tree:toggle_at_line(line_number)
+    local node = self.line_to_node[line_number]
+    if not node or not node:is_container() then
+        return false
+    end
+
+    if not node.is_expanded then
+        -- Expanding: load children if needed
+        local success = self:load_children(node)
+        if not success then
+            return false
+        end
+    end
+
+    -- Toggle state
+    node.is_expanded = not node.is_expanded
+    return true
+end
+
+return Tree