local buffers = require("nvim-tree.buffers")

local HL_POSITION = require("nvim-tree.enum").HL_POSITION
local ICON_PLACEMENT = require("nvim-tree.enum").ICON_PLACEMENT

local Decorator = require("nvim-tree.renderer.decorator")
local DirectoryNode = require("nvim-tree.node.directory")

---@class (exact) DecoratorModified: Decorator
---@field icon HighlightedString?
local DecoratorModified = Decorator:extend()

---@class DecoratorModified
---@overload fun(explorer: DecoratorArgs): DecoratorModified

---@private
---@param args DecoratorArgs
function DecoratorModified:new(args)
  Decorator.new(self, {
    explorer       = args.explorer,
    enabled        = true,
    hl_pos         = HL_POSITION[args.explorer.opts.renderer.highlight_modified] or HL_POSITION.none,
    icon_placement = ICON_PLACEMENT[args.explorer.opts.renderer.icons.modified_placement] or ICON_PLACEMENT.none,
  })

  if not self.enabled then
    return
  end

  if self.explorer.opts.renderer.icons.show.modified then
    self.icon = {
      str = self.explorer.opts.renderer.icons.glyphs.modified,
      hl = { "NvimTreeModifiedIcon" },
    }
    self:define_sign(self.icon)
  end
end

---Modified icon: modified.enable, renderer.icons.show.modified and node is modified
---@param node Node
---@return HighlightedString[]|nil icons
function DecoratorModified:calculate_icons(node)
  if self.enabled and buffers.is_modified(node) then
    return { self.icon }
  end
end

---Modified highlight: modified.enable, renderer.highlight_modified and node is modified
---@param node Node
---@return string|nil group
function DecoratorModified:calculate_highlight(node)
  if not self.enabled or self.hl_pos == HL_POSITION.none or not buffers.is_modified(node) then
    return nil
  end

  if node:is(DirectoryNode) then
    return "NvimTreeModifiedFolderHL"
  else
    return "NvimTreeModifiedFileHL"
  end
end

return DecoratorModified