Folder = {
	PARENT = 0,
	CURRENT = 1,
	PREVIEW = 2,
}

function Folder:by_kind(kind)
	if kind == self.PARENT then
		return cx.active.parent
	elseif kind == self.CURRENT then
		return cx.active.current
	elseif kind == self.PREVIEW then
		return cx.active.preview.folder
	end
end

function Folder:highlighted_name(file)
	-- Complete prefix when searching across directories
	local prefix = file:prefix() or ""
	if prefix ~= "" then
		prefix = prefix .. "/"
	end

	-- Range highlighting for filenames
	local highlights = file:highlights()
	local spans = ui.highlight_ranges(prefix .. file.name, highlights)

	-- Show symlink target
	if MANAGER.show_symlink and file.link_to ~= nil then
		spans[#spans + 1] = ui.Span(" -> " .. tostring(file.link_to)):italic()
	end

	if highlights == nil or not file:is_hovered() then
		return spans
	end

	local found = file:found()
	if found ~= nil then
		spans[#spans + 1] = ui.Span("  ")
		spans[#spans + 1] = ui.Span(string.format("[%d/%d]", found[1] + 1, found[2])):style(THEME.manager.find_position)
	end
	return spans
end

function Folder:linemode(area)
	local mode = cx.active.conf.linemode
	if mode == "none" then
		return {}
	end

	local lines = {}
	for _, f in ipairs(self:by_kind(self.CURRENT).window) do
		local spans = { ui.Span(" ") }
		if mode == "size" then
			local size = f:size()
			spans[#spans + 1] = ui.Span(size and utils.readable_size(size) or "")
		elseif mode == "mtime" then
			spans[#spans + 1] = ui.Span(os.date("%y-%m-%d %H:%M", f.modified))
		elseif mode == "permissions" then
			spans[#spans + 1] = ui.Span(f:permissions() or "")
		end
		lines[#lines + 1] = ui.Line(spans)
	end
	return ui.Paragraph(area:padding(ui.Padding.right(1)), lines):align(ui.Alignment.RIGHT)
end

function Folder:markers(area, markers)
	if #markers == 0 then
		return {}
	end

	local elements = {}
	local append = function(last)
		local p = ui.Bar(
			ui.Rect {
				x = math.max(1, area.x) - 1,
				y = area.y + last[1] - 1,
				w = 1,
				h = 1 + last[2] - last[1],
			},
			ui.Position.LEFT
		)

		if last[3] == 1 then
			p = p:style(THEME.manager.marker_copied)
		elseif last[3] == 2 then
			p = p:style(THEME.manager.marker_cut)
		elseif last[3] == 3 then
			p = p:style(THEME.manager.marker_selected)
		end
		elements[#elements + 1] = p
	end

	local last = { markers[1][1], markers[1][1], markers[1][2] } -- start, end, type
	for _, m in ipairs(markers) do
		if m[1] - last[2] > 1 or last[3] ~= m[2] then
			append(last)
			last = { m[1], m[1], m[2] }
		else
			last[2] = m[1]
		end
	end

	append(last)
	return elements
end

function Folder:parent(area)
	local folder = self:by_kind(self.PARENT)
	if folder == nil then
		return {}
	end

	local items = {}
	for _, f in ipairs(folder.window) do
		local item = ui.ListItem(" " .. f:icon() .. " " .. f.name .. " ")
		if f:is_hovered() then
			item = item:style(THEME.manager.hovered)
		else
			item = item:style(f:style())
		end

		items[#items + 1] = item
	end

	return { ui.List(area, items) }
end

function Folder:current(area)
	local markers = {}
	local items = {}
	for i, f in ipairs(self:by_kind(self.CURRENT).window) do
		local name = self:highlighted_name(f)

		-- Highlight hovered file
		local item = ui.ListItem(ui.Line { ui.Span(" " .. f:icon() .. " "), table.unpack(name) })
		if f:is_hovered() then
			item = item:style(THEME.manager.hovered)
		else
			item = item:style(f:style())
		end
		items[#items + 1] = item

		-- Mark yanked/selected files
		local yanked = f:is_yanked()
		if yanked ~= 0 then
			markers[#markers + 1] = { i, yanked }
		elseif f:is_selected() then
			markers[#markers + 1] = { i, 3 }
		end
	end
	return utils.flat { ui.List(area, items), self:linemode(area), table.unpack(self:markers(area, markers)) }
end

function Folder:preview(area)
	local folder = self:by_kind(self.PREVIEW)
	if folder == nil then
		return {}
	end

	local items = {}
	for _, f in ipairs(folder.window) do
		local item = ui.ListItem(" " .. f:icon() .. " " .. f.name .. " ")
		if f:is_hovered() then
			item = item:style(THEME.manager.preview_hovered)
		else
			item = item:style(f:style())
		end
		items[#items + 1] = item
	end

	return { ui.List(area, items) }
end

function Folder:render(area, args)
	if args.kind == self.PARENT then
		return self:parent(area)
	elseif args.kind == self.CURRENT then
		return self:current(area)
	elseif args.kind == self.PREVIEW then
		return self:preview(area)
	end
end