local M = {}

local WINDOW_WIDTH = 960
local WINDOW_HEIGHT = 480
local POSITION_HORIZONTAL = 800
local VISIBLE_VERTIVCAL = 40
local HIDDEN_VERTICAL = -WINDOW_HEIGHT

local WS_HIDE = 'special:wsDropdown'
local TAG_NEW = 'dropdownNew'

local window_addrs = {}
local new_id = nil

hl.on('window.open', function (w)
    for _, v in ipairs(w.tags) do
        if v == TAG_NEW .. '*' and new_id then
            window_addrs[new_id] = w.address
            hl.dispatch(hl.dsp.window.tag { tag = '-' .. TAG_NEW, window = 'address:' .. w.address })
            new_id = nil
            return
        end
    end
end)


local function generate_id(cmd)
    local id = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 }

    local id_idx = 1
    local id_len = #id
    for i = 1, #cmd do
        local byteVal = string.byte(cmd, i)
        id[id_idx] = id[id_idx] ~ byteVal
        id_idx = id_idx % id_len + 1
    end

    local CHARS = '0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ'
    local CHARS_LEN = #CHARS
    for i = 1, id_len do
        local pos = id[i] % CHARS_LEN + 1
        id[i] = CHARS:sub(pos, pos)
    end

    return table.concat(id)
end

local function hide_window(window)
    hl.dispatch(hl.dsp.window.pin { action = 'off', window = window })
    hl.dispatch(hl.dsp.window.move { x = POSITION_HORIZONTAL, y = HIDDEN_VERTICAL, relative = false, window = window })
    hl.dispatch(hl.dsp.window.move { workspace = WS_HIDE, follow = false, window = window })
end

local function hide_others_and_show(window)
    for id, addr in pairs(window_addrs) do
        local current_window = 'address:' .. addr
        if current_window ~= window then
            local hl_window = hl.get_window(current_window)
            if hl_window then
                if hl.get_window(current_window).pinned then
                    hide_window(current_window)
                end
            else
                window_addrs[id] = nil
            end
        else
            hl.dispatch(hl.dsp.window.move { workspace = 'm+0', follow = true, window = window })
            hl.dispatch(hl.dsp.window.move { x = POSITION_HORIZONTAL, y = VISIBLE_VERTIVCAL, relative = false, window = window })
            hl.dispatch(hl.dsp.window.pin { action = 'on', window = window })
        end
    end
end

M.dsp = {}
function M.dsp.toggle(cmd)
    assert(cmd)
    return function ()
        local id = generate_id(cmd)
        local addr = window_addrs[id]
        if addr then
            local window = 'address:' .. addr
            local hl_window = hl.get_window(window)
            if hl_window then
                if hl_window.pinned then
                    hide_window(window)
                else
                    hide_others_and_show(window)
                end
                return
            end
        end

        hide_others_and_show('')
        new_id = id
        hl.exec_cmd(cmd, {
            float = true,
            size = { WINDOW_WIDTH, WINDOW_HEIGHT },
            move = { POSITION_HORIZONTAL, VISIBLE_VERTIVCAL },
            pin = true,
            tag = TAG_NEW,
        })
    end
end

return M