local M = {}

---@class inbox.TextChunk
---@field [1] string text
---@field [2] string hl

---@param text string
---@param length nil|integer
---@return string
function M.rpad(text, length)
	if not length then
		return text
	end

	if text:len() <= length then
		return text .. string.rep(" ", length - text:len())
	else
		return string.sub(text, 1, length - 3) .. "..."
	end
end

---@param cols (string | inbox.TextChunk)[]
---@param col_widths integer[]
---@return string
---@return any[][] List of highlights {group, col_start, col_end}
function M.render_row(cols, col_widths)
	local pieces = {}
	local highlights = {}

	local col = 0
	for i, chunk in ipairs(cols) do
		local text, hl
		if type(chunk) == "table" then
			text, hl = unpack(chunk) --[[@as string]]
		else
			text = chunk --[[@as string]]
		end
		text = M.rpad(text, col_widths[i])
		table.insert(pieces, text)
		local col_end = col + text:len() + 1
		if hl then
			table.insert(highlights, { hl, col, col_end })
		end
		col = col_end
	end

	return table.concat(pieces, " "), highlights
end

---@param rows (string | inbox.TextChunk)[][]
---@param col_widths integer[]
---@return string[]
---@return any[][] List of highlights {group, lnum, col_start, col_end}
function M.render_table(rows, col_widths)
	local lines = {}
	local highlights = {}

	for lnum, cols in ipairs(rows) do
		local line, line_hls = M.render_row(cols, col_widths)
		table.insert(lines, line)

		for _, hl in pairs(line_hls) do
			local group, col_start, col_end = unpack(hl)
			table.insert(highlights, { group, lnum, col_start, col_end })
		end
	end

	return lines, highlights
end

---@param winid integer
---@param cols (string | inbox.TextChunk)[]
---@param col_widths integer[]
function M.render_winbar(winid, cols, col_widths)
	local winbar = M.render_row(cols, col_widths)
	local offset = vim.fn.getwininfo(winid)[1].textoff + 1
	vim.api.nvim_set_option_value("winbar", string.rep(" ", offset) .. winbar, { scope = "local", win = winid })
end

return M