local M = {}

---@param win integer
---@return boolean
local function has_border(win)
    local b = vim.api.nvim_win_get_config(win).border
    if not b or b == "none" or b == "" then
        return false
    end
    if type(b) == "table" and #b == 0 then
        return false
    end
    return true
end

---@param lines string[]
---@param opts? { min_width?: integer, padding?: integer }
---@return integer width
---@return integer height
function M.size_for(lines, opts)
    opts = opts or {}
    local width = 1
    for _, l in ipairs(lines) do
        local w = vim.api.nvim_strwidth(l)
        if w > width then
            width = w
        end
    end
    width = math.min(
        math.max(width + (opts.padding or 1), opts.min_width or 30),
        100,
        vim.o.columns - 4
    )
    local height =
        math.min(math.max(#lines, 1), 20, math.floor(vim.o.lines / 2))
    return width, height
end

---@param pbuf integer
---@param win integer
---@param ns integer
function M.paint_overflow(pbuf, win, ns)
    vim.schedule(function()
        if
            not vim.api.nvim_buf_is_valid(pbuf)
            or not vim.api.nvim_win_is_valid(win)
        then
            return
        end
        vim.api.nvim_buf_clear_namespace(pbuf, ns, 0, -1)
        local total = vim.api.nvim_buf_line_count(pbuf)
        local top, bottom = unpack(vim.api.nvim_win_call(win, function()
            return { vim.fn.line("w0"), vim.fn.line("w$") }
        end)) ---@cast top integer
        ---@cast bottom integer
        local needs_top = top > 1
        local needs_bottom = bottom < total
        if has_border(win) then
            pcall(vim.api.nvim_win_set_config, win, {
                title = needs_top and { { "▲ ", "FloatBorder" } } or "",
                title_pos = needs_top and "right" or nil,
                footer = needs_bottom and { { "▼ ", "FloatBorder" } } or "",
                footer_pos = needs_bottom and "right" or nil,
            })
            return
        end
        if needs_top then
            pcall(vim.api.nvim_buf_set_extmark, pbuf, ns, top - 1, 0, {
                virt_text = { { "▲ ", "GitPopupEnd" } },
                virt_text_pos = "right_align",
            })
        end
        if needs_bottom then
            pcall(vim.api.nvim_buf_set_extmark, pbuf, ns, bottom - 1, 0, {
                virt_text = { { "▼ ", "GitPopupEnd" } },
                virt_text_pos = "right_align",
            })
        end
    end)
end

return M