feat(item): util method to add missing text to items

lua/trouble/item.lua

@@ -1,4 +1,5 @@
 local Cache = require("trouble.cache")
+local Util = require("trouble.util")
 
 ---@alias trouble.Pos {[1]:number, [2]:number}
 
@@ -49,4 +50,43 @@ function M:__index(k)
   end
 end
 
+---@param items trouble.Item[]
+function M.add_text(items)
+  local buf_rows = {} ---@type table<number, number[]>
+
+  for _, item in ipairs(items) do
+    if not item.item.text then
+      -- schedule to get the lines
+      buf_rows[item.buf] = buf_rows[item.buf] or {}
+      for r = item.pos[1], item.end_pos and item.end_pos[1] or item.pos[1] do
+        table.insert(buf_rows[item.buf], r)
+      end
+    end
+  end
+
+  -- get the lines and range text
+  local buf_lines = {} ---@type table<number, table<number, string>>
+  for buf, rows in pairs(buf_rows) do
+    buf_lines[buf] = Util.get_lines(buf, rows)
+  end
+  for _, item in ipairs(items) do
+    if not item.item.text then
+      local lines = {} ---@type string[]
+      for row = item.pos[1], item.end_pos[1] do
+        local line = buf_lines[item.buf][row] or ""
+        if row == item.pos[1] and row == item.end_pos[1] then
+          line = line
+        elseif row == item.pos[1] then
+          line = line:sub(item.pos[2] + 1)
+        elseif row == item.end_pos[1] then
+          line = line:sub(1, item.end_pos[2]) --[[@as string]]
+        end
+        lines[#lines + 1] = line
+      end
+      item.item.text = table.concat(lines, "\n")
+    end
+  end
+  return items
+end
+
 return M