-- Reference:
-- https://www.cnblogs.com/yf-zhao/p/16018481.html
-- https://zhuanlan.zhihu.com/p/425951648

local ffi = require "ffi"

ffi.cdef [[
    typedef unsigned int UINT, HWND, WPARAM;
    typedef unsigned long LPARAM, LRESULT;
    LRESULT SendMessageA(HWND hWnd, UINT Msg, WPARAM wParam, LPARAM lParam);
    HWND ImmGetDefaultIMEWnd(HWND unnamedParam1);
    HWND GetForegroundWindow();
]]

local user32 = ffi.load "user32.dll"
local imm32 = ffi.load "imm32.dll"

local ime_hwnd
local ime_group = vim.api.nvim_create_augroup("ime_toggle", { clear = true })

-- Get ime control's hwnd after InsertEnter or CmdlineEnter
-- to ensure getting correct foregroundwindow
vim.api.nvim_create_autocmd({ "InsertEnter", "CmdlineEnter" }, {
    group = ime_group,
    once = true,
    desc = "Get ime control hwnd attached to nvim window",
    callback = function()
        ime_hwnd = imm32.ImmGetDefaultIMEWnd(user32.GetForegroundWindow())
    end,
})

local WM_IME_CONTROL = 0x283
local IMC_GETCONVERSIONMODE = 0x001
local IMC_SETCONVERSIONMODE = 0x002 -- It's said this value differs on different ime, I'm not sure
local ime_mode_ch = 1025
local ime_mode_en = 0

local function set_ime_mode(mode)
    return user32.SendMessageA(ime_hwnd, WM_IME_CONTROL, IMC_SETCONVERSIONMODE, mode)
end

local function get_ime_mode()
    return user32.SendMessageA(ime_hwnd, WM_IME_CONTROL, IMC_GETCONVERSIONMODE, 0)
end

vim.api.nvim_create_autocmd({ "InsertLeave", "CmdlineLeave" }, {
    group = ime_group,
    desc = "Toggle ime to English mode on normal mode",
    callback = function()
        if ime_mode_ch == get_ime_mode() then
            set_ime_mode(ime_mode_en)
        end
    end,
})

return {
  "keaising/im-select.nvim",
  config = function()
    require("im_select").setup({
      -- IM will be set to `default_im_select` in `normal` mode
      -- For Windows/WSL, default: "1033", aka: English US Keyboard
      -- For macOS, default: "com.apple.keylayout.ABC", aka: US
      -- For Linux, default:
      --               "keyboard-us" for Fcitx5
      --               "1" for Fcitx
      --               "xkb:us::eng" for ibus
      -- You can use `im-select` or `fcitx5-remote -n` to get the IM's name
      default_im_select = "com.apple.keylayout.ABC",

      -- Can be binary's name or binary's full path,
      -- e.g. 'im-select' or '/usr/local/bin/im-select'
      -- For Windows/WSL, default: "im-select.exe"
      -- For macOS, default: "im-select"
      -- For Linux, default: "fcitx5-remote" or "fcitx-remote" or "ibus"
      default_command = "im-select",

      -- Restore the default input method state when the following events are triggered
      set_default_events = { "VimEnter", "FocusGained", "InsertLeave", "CmdlineLeave" },

      -- Restore the previous used input method state when the following events
      -- are triggered, if you don't want to restore previous used im in Insert mode,
      -- e.g. deprecated `disable_auto_restore = 1`, just let it empty
      -- as `set_previous_events = {}`
      set_previous_events = { "InsertEnter" },

      -- Show notification about how to install executable binary when binary missed
      keep_quiet_on_no_binary = false,

      -- Async run `default_command` to switch IM or not
      async_switch_im = true,
    })
  end,
}

return {
    {
        "keaising/im-select.nvim",
        config = function()
            require('im_select').setup({
                -- IM will be set to `default_im_select` in `normal` mode
                -- For Windows/WSL, default: "1033", aka: English US Keyboard
                -- For macOS, default: "com.apple.keylayout.ABC", aka: US
                -- For Linux, default:
                --               "keyboard-us" for Fcitx5
                --               "1" for Fcitx
                --               "xkb:us::eng" for ibus
                -- You can use `im-select` or `fcitx5-remote -n` to get the IM's name
                default_im_select  = "com.apple.keylayout.ABC",

                -- Can be binary's name or binary's full path,
                -- e.g. 'im-select' or '/usr/local/bin/im-select'
                -- For Windows/WSL, default: "im-select.exe"
                -- For macOS, default: "im-select"
                -- For Linux, default: "fcitx5-remote" or "fcitx-remote" or "ibus"
                default_command = '/usr/local/bin/im-select', -- macOS13 Apple silicon上用的不是这个，而是/opt/homebrew那个

                -- Restore the default input method state when the following events are triggered
                -- set_default_events = { "VimEnter", "FocusGained", "InsertLeave", "CmdlineLeave" },

                -- Restore the previous used input method state when the following events
                -- are triggered, if you don't want to restore previous used im in Insert mode,
                -- e.g. deprecated `disable_auto_restore = 1`, just let it empty
                -- as `set_previous_events = {}`
                -- set_previous_events = { "InsertEnter" },

                -- Show notification about how to install executable binary when binary missed
                keep_quiet_on_no_binary = false,

                -- Async run `default_command` to switch IM or not
                async_switch_im = false
            })
        end,
    }
}

 -- im-select
  {
    "keaising/im-select.nvim",
    lazy = false,
    config = function()
      require("im_select").setup {
        default_im_select = "1033",
        default_command = "im-select.exe",
        set_default_events = { "VimEnter", "FocusGained", "InsertLeave", "CmdlineLeave" },
        set_previous_events = { "InsertEnter" },
        keep_quiet_on_no_binary = false,
        async_switch_im = true,
      }
    end,
  },

-- get node right before user's cursor
local function get_node_before_cursor()
    local cursor_pos = vim.api.nvim_win_get_cursor(0)
    -- because nvim_win_get_cursor is (1, 0)-indexed
    -- but vim.treesitter.get_node is (0, 0)-indexed
    -- so row must decrease 1
    -- and in insert mode, cursor's position is in cursor right
    -- but we need detect the char just before the cursor
    -- so col need decrease 1
    local row, col = cursor_pos[1] - 1, cursor_pos[2] - 1
    if col < 0 then
        return nil
    end
    local node = vim.treesitter.get_node({ pos = { row, col } })
    return node
end

local function would_alternative_im_better(t)
    local specific_type = { "comment", "comment_content", "string_content", "string" }
    for _, v in ipairs(specific_type) do
        if t == v then
            return true
        end
    end
    return false
end

local function determine_which_IM_and_switch(ignore_last_node_type)
    local current_node = get_node_before_cursor()
    if current_node == nil then
        return
    end
    local current_node_type = current_node:type()

    -- when type comment or string, switch IM to alternative IM
    if would_alternative_im_better(current_node_type) then
        if ignore_last_node_type or not would_alternative_im_better(last_node_type) then
            switch_to_alternative_im()
        end
    end

    -- when type comment or string finish, switch IM to default IM
    if not would_alternative_im_better(current_node_type) then
        if ignore_last_node_type or would_alternative_im_better(last_node_type) then
            switch_to_default_im()
        end
    end
    last_node_type = current_node:type()
end

M.setup = function(opts)
    -- some code here .......
    local group_id = vim.api.nvim_create_augroup("im-select", { clear = true })

    if #C.set_default_events > 0 then
        vim.api.nvim_create_autocmd(C.set_default_events, {
            callback = switch_to_default_im,
            group = group_id,
        })
    end
    vim.api.nvim_create_autocmd({ "InsertEnter" }, {
        callback = function()
            determine_which_IM_and_switch(true)
        end
    })
    vim.api.nvim_create_autocmd({ "TextChangedI" }, {
        callback = function()
            determine_which_IM_and_switch(false)
        end
    })
    -- some code here .......
end

return {
  "keaising/im-select.nvim",
  config = function()
    require("im-select").setup {
      default_im_select = "com.apple.keylayout.ABC",
    }
  end,
}

  {
    "keaising/im-select.nvim",
    opts = {
      set_default_events = { "VimEnter", "InsertLeave", "CmdlineLeave" },
    },
    config = true
  }