feat: implement interactable dap hover

lua/ow/dap/hover/node.lua

@@ -0,0 +1,141 @@
+-- Tree node representation for DAP variables
+local Content = require("ow.dap.hover.content")
+local log = require("ow.log")
+
+---@class ow.dap.hover.Node
+---@field item ow.dap.Item The DAP item this node represents
+---@field parent ow.dap.hover.Node? Parent node
+---@field children ow.dap.hover.Node[] Child nodes
+---@field is_expanded boolean Whether this node is expanded
+---@field line_number integer Buffer line number where this node is displayed
+---@field is_last_child boolean Whether this is the last child of its parent
+local Node = {}
+Node.__index = Node
+
+---Create a new tree node
+---@param item ow.dap.Item
+---@param parent ow.dap.hover.Node?
+---@return ow.dap.hover.Node
+function Node.new(item, parent)
+    return setmetatable({
+        item = item,
+        parent = parent,
+        children = {},
+        is_expanded = false,
+        line_number = -1,
+        is_last_child = false,
+    }, Node)
+end
+
+---Check if this node represents a container (struct/array)
+---@return boolean
+function Node:is_container()
+    return self.item.variablesReference and self.item.variablesReference > 0
+        or false
+end
+
+---Get the tree prefix for this node (├─, └─, │, etc.)
+---@return string
+function Node:get_tree_prefix()
+    if not self.parent then
+        return "" -- Root node has no prefix
+    end
+
+    local prefix = ""
+
+    -- Walk up the tree to build the prefix
+    local node = self.parent
+    while node and node.parent do
+        if node.is_last_child then
+            prefix = "   " .. prefix
+        else
+            prefix = "│  " .. prefix
+        end
+        node = node.parent
+    end
+
+    -- Add the final branch character
+    if self.is_last_child then
+        prefix = prefix .. "└─ "
+    else
+        prefix = prefix .. "├─ "
+    end
+
+    return prefix
+end
+
+---@return boolean
+function Node:is_c_array_element()
+    return self.item.name:match("^%[?%d+%]?$") ~= nil
+end
+
+---@return boolean
+function Node:is_c_pointer_child()
+    return self.parent
+            and self.parent.item.type:match(
+                "%*%s*[const%s]*[volatile%s]*[restrict%s]*$"
+            ) ~= nil
+        or false
+end
+
+---@return string
+function Node:format_c_expression()
+    if self:is_c_array_element() then
+        return string.format(
+            "%s = (%s) %s",
+            self.item.name,
+            self.item.type,
+            self.item.value
+        )
+    end
+
+    if self:is_c_pointer_child() then
+        return string.format("*%s = %s", self.parent.item.name, self.item.value)
+    end
+
+    return string.format(
+        "%s %s = %s",
+        self.item.type,
+        self.item.name,
+        self.item.value
+    )
+end
+
+---Format this node as highlighted content
+---@param session dap.Session DAP session for making requests
+---@return ow.dap.hover.Content
+function Node:format(session)
+    local content = Content.new()
+
+    -- Add expansion marker for containers
+    if self:is_container() then
+        local marker = self.is_expanded and "-" or "+"
+        content:add(marker .. " ", "@comment")
+    else
+        content:add("  ")
+    end
+
+    -- Add tree prefix
+    local tree_prefix = self:get_tree_prefix()
+    if tree_prefix ~= "" then
+        content:add(tree_prefix, "@comment")
+    end
+
+    local stmt
+    if session.filetype == "c" or session.filetype == "cpp" then
+        stmt = self:format_c_expression()
+    else
+        error(
+            string.format("Formatting for %s not implemented", session.filetype)
+        )
+    end
+    content:add_with_treesitter(stmt, session.filetype)
+
+    if self.item.value == "" then
+        content:add("...", "@comment")
+    end
+
+    return content
+end
+
+return Node