local interestingwords = (function()
  local api = vim.api
  local fn = vim.fn
  local uv = vim.loop

  local m = {}

  m.words = {}
  m.colors = {}
  m.limits = {}
  m.capcity = 0
  m.next = 1

  local get_default_config = function()
    return {
      colors = { "#aeee00", "#ff0000", "#0000ff", "#b88823", "#ffa724", "#ff2c4b" },
      search_count = true,
      navigation = true,
      scroll_center = true,
      search_key = "<leader>hl",
      cancel_search_key = "<leader>lh",
      color_key = "<leader>ih",
      cancel_color_key = "<leader>hi",
      select_mode = "random", -- random or loop
    }
  end

  local init_colors = function()
    for i, v in pairs(m.config.colors) do
      local color = "InterestingWord" .. i

      api.nvim_set_hl(0, color, { bg = v, fg = "Black" })
      m.colors[color] = 595129 + i
      m.capcity = m.capcity + 1
    end
    m.limits.min = 595129 + 1
    m.limits.max = 595129 + #m.config.colors
  end

  local get_reg_ex = function(word)
    if vim.o.ignorecase and (not vim.o.smartcase or fn.match(word, "\\u") == -1) then
      return "\\c\\V" .. word
    else
      return "\\C\\V" .. word
    end
  end

  local get_visual_selection = function()
    local lines
    local start_row, start_col = fn.getpos("v")[2], fn.getpos("v")[3]
    local end_row, end_col = fn.getpos(".")[2], fn.getpos(".")[3]
    if end_row < start_row then
      start_row, end_row = end_row, start_row
      start_col, end_col = end_col, start_col
    elseif end_row == start_row and end_col < start_col then
      start_col, end_col = end_col, start_col
    end
    start_row = start_row - 1
    start_col = start_col - 1
    end_row = end_row - 1
    if api.nvim_get_mode().mode == "V" then
      lines = api.nvim_buf_get_text(0, start_row, 0, end_row, -1, {})
    elseif api.nvim_get_mode().mode == "v" then
      lines = api.nvim_buf_get_text(0, start_row, start_col, end_row, end_col, {})
    end
    vim.cmd("normal! ")
    if lines == nil then
      return ""
    end

    local line = ""
    for i, v in ipairs(lines) do
      if i == 1 then
        line = line .. fn.escape(v, "\\")
      else
        line = line .. "\\n" .. fn.escape(v, "\\")
      end
    end

    return line
  end

  local uncolor = function(word)
    if m.words[word] then
      local windows = api.nvim_list_wins()
      for _, i in ipairs(windows) do
        pcall(function()
          fn.matchdelete(m.words[word].mid, i)
        end)
      end
      m.colors[m.words[word].color] = m.words[word].mid
      m.words[word] = nil
    end
  end

  local get_rest_color_random = function()
    local res = {}
    for k, v in pairs(m.colors) do
      if v ~= 0 then
        table.insert(res, { color = k, mid = v })
      end
    end
    if #res == 0 then
      return nil
    end

    return res[math.random(#res)]
  end

  local find_who_use_this = function(target_color)
    for word, color in pairs(m.words) do
      if color.color == target_color then
        return word
      end
    end
    return nil
  end

  local get_rest_color_loop = function()
    if m.next > m.capcity then
      m.next = 1
    end
    local color = "InterestingWord" .. m.next
    if m.colors[color] == 0 then
      local word = find_who_use_this(color)
      if word ~= nil then
        uncolor(word)
      else
        return nil
      end
    end
    m.next = m.next + 1
    return { color = color, mid = m.colors[color] }
  end

  local get_rest_color = function()
    local selector = {
      ["random"] = get_rest_color_random,
      ["loop"] = get_rest_color_loop,
    }
    return selector[m.config.select_mode]()
  end

  local color = function(word)
    local color = get_rest_color()
    if not color then
      vim.notify("InterestingWords: max number of highlight groups reached")
      return
    end

    m.words[word] = {}
    m.words[word].color = color.color
    m.words[word].mid = color.mid
    m.colors[color.color] = 0

    local windows = api.nvim_list_wins()
    for _, i in ipairs(windows) do
      pcall(function()
        fn.matchadd(m.words[word].color, word, 1, m.words[word].mid, { window = i })
      end)
    end
  end

  local recolorAllWords = function()
    for k, v in pairs(m.words) do
      pcall(function()
        fn.matchadd(v.color, k, 1, v.mid, { window = 0 })
      end)
    end
  end

  local nearest_word_at_cursor = function()
    for _, match_item in pairs(fn.getmatches()) do
      if match_item.id >= m.limits.min or match_item.id <= m.limits.max then
        local buf_content = fn.join(api.nvim_buf_get_lines(0, 0, -1, {}), "\n")
        local cur_pos = #fn.join(api.nvim_buf_get_lines(0, 0, fn.line(".") - 1, {}), "\n") +
        ((fn.line(".") == 1) and 0 or 1) + fn.col(".") - 1
        local lst_pos = 0
        while true do
          local mat_pos = fn.matchstrpos(buf_content, match_item.pattern, lst_pos, 1)
          if mat_pos[1] == "" then
            break
          end
          if cur_pos >= mat_pos[2] and cur_pos < mat_pos[3] then
            return match_item.pattern
          end
          lst_pos = mat_pos[3]
        end
      end
    end
  end

  local filter = function(word)
    if #word <= 4 or (string.sub(word, 1, 4) ~= "\\c\\V" and string.sub(word, 1, 4) ~= "\\C\\V") then
      return word
    else
      return string.sub(word, 5, -1)
    end
  end

  local display_search_count = function(word, count)
    local icon = ""
    m.search_count_extmark_id = api.nvim_buf_set_extmark(0, m.search_count_namespace, fn.line(".") - 1, 0, {
      virt_text_pos = "eol",
      virt_text = {
        { icon .. count, "NonText" },
      },
      hl_mode = "combine",
    })
    m.search_count_cache = icon .. " " .. filter(word) .. count
    m.search_count_timer:again()
  end

  local hide_search_count = function(bufnr)
    if m.search_count_namespace then
      api.nvim_buf_del_extmark(bufnr, m.search_count_namespace, m.search_count_extmark_id)
    end
  end

  local scroll_timer = vim.loop.new_timer()
  local function scroll_up(cnt)
    return vim.cmd("normal! " .. cnt .. "")
  end

  local function scroll_down(cnt)
    return vim.cmd("normal! " .. cnt .. "")
  end

  local function stop_scrolling()
    scroll_timer:stop()
  end

  local scroll_to_center = function()
    local window_height = api.nvim_win_get_height(0)
    local lines = fn.winline() - math.floor(window_height / 2)
    if lines == 0 then
      return
    end
    local up = lines > 0
    lines = math.abs(lines)

    local move_lines = function(n)
      return math.floor(n / 5) + 1
    end

    local each_time = function()
      local lines_bak = lines
      local circles = 0
      while lines_bak ~= 0 do
        lines_bak = lines_bak - move_lines(lines_bak)
        circles = circles + 1
      end
      local pseudo_total_time = 300 + 15 * math.min((lines - 11), 10) + lines
      return math.floor(pseudo_total_time / circles)
    end
    local t = each_time()
    local time_total = 0

    local scroll_callback = function()
      local cnt = move_lines(lines)
      if lines == 0 then
        stop_scrolling()
        return
      else
        lines = lines - cnt
      end

      if up then
        scroll_up(cnt)
      else
        scroll_down(cnt)
      end
      time_total = time_total + t
    end

    scroll_timer:start(t, t, vim.schedule_wrap(scroll_callback))
  end

  m.lualine_get = function()
    return m.search_count_cache
  end

  m.lualine_has = function()
    return m.search_count_cache ~= ""
  end

  m.init_search_count = function()
    m.search_count_extmark_id = 0
    m.search_count_namespace = api.nvim_create_namespace("custom/search_count")
    m.search_count_timer = vim.loop.new_timer()
    m.search_count_timer:start(0, 5000, function()
      m.search_count_cache = ""
      vim.defer_fn(function()
        hide_search_count(0)
      end, 100)
      m.search_count_timer:stop()
    end)

    vim.api.nvim_create_autocmd({ "CmdlineLeave" }, {
      pattern = { "*" },
      callback = function(event)
        if vim.v.event.abort then
          return
        end
        if event.match == "/" or event.match == "?" then
          vim.defer_fn(function()
            local searched = m.search_count(fn.getreg("/"))
            if searched and m.config.scroll_center then
              scroll_to_center()
            end
          end, 100)
        end
      end,
    })
  end

  m.search_count = function(word)
    hide_search_count(0)
    if word == "" then
      return false
    end

    local cur_cnt = 0
    local total_cnt = 0
    local buf_content = fn.join(api.nvim_buf_get_lines(0, 0, -1, {}), "\n")
    local cur_pos = #fn.join(api.nvim_buf_get_lines(0, 0, fn.line(".") - 1, {}), "\n") + ((fn.line(".") == 1) and 0 or 1) +
    fn.col(".") - 1
    local lst_pos = 0
    while true do
      local mat_pos = fn.matchstrpos(buf_content, word, lst_pos, 1)
      if mat_pos[1] == "" then
        break
      end
      total_cnt = total_cnt + 1
      if cur_pos >= mat_pos[2] and cur_pos < mat_pos[3] then
        cur_cnt = total_cnt
      end
      lst_pos = mat_pos[3]
    end

    if total_cnt == 0 or cur_cnt == 0 then
      return false
    end

    local count = " [" .. cur_cnt .. "/" .. total_cnt .. "]"
    display_search_count(word, count)

    return true
  end

  m.NavigateToWord = function(forward)
    local word = nearest_word_at_cursor()
    if not word then
      word = fn.getreg("/")
    end
    if word == "" then
      return
    end

    local search_flag = ""
    if not forward then
      search_flag = "b"
    end
    local n = fn.search(word, search_flag)
    if n ~= 0 then
      if m.config.scroll_center then
        scroll_to_center()
      end
    else
      vim.notify("Pattern not found: " .. filter(word))
      return
    end

    if m.config.search_count then
      m.search_count(word)
    end
  end

  m.InterestingWord = function(mode, search)
    local word = ""
    if mode == "v" then
      word = get_visual_selection()
    else
      word = "\\<" .. fn.expand("<cword>") .. "\\>"
    end
    if #word == 0 then
      return
    end
    word = get_reg_ex(word)

    if search then
      if word == fn.getreg("/") then
        fn.setreg("/", "")
        word = ""
      else
        fn.setreg("/", word)
        vim.cmd("set hls")
      end
    else
      if m.words[word] then
        uncolor(word)
        word = ""
      else
        color(word)
      end
    end

    if m.config.search_count then
      m.search_count(word)
    end
  end

  m.UncolorAllWords = function(search)
    m.search_count("")
    if search then
      fn.setreg("/", "")
    else
      local windows = api.nvim_list_wins()
      for _, v in pairs(m.words) do
        for _, i in ipairs(windows) do
          pcall(function()
            fn.matchdelete(v.mid, i)
          end)
        end
        m.colors[v.color] = v.mid
      end

      m.words = {}
    end
  end

  m.setup = function(opt)
    opt = opt or {}
    m.config = vim.tbl_deep_extend("force", get_default_config(), opt)

    init_colors()
    math.randomseed(uv.now())

    local group = api.nvim_create_augroup("InterestingWordsGroup", { clear = true })
    api.nvim_create_autocmd({ "WinEnter" }, {
      callback = function()
        recolorAllWords()
        local windows = api.nvim_list_wins()
        for _, i in ipairs(windows) do
          hide_search_count(api.nvim_win_get_buf(fn.win_getid(i)))
        end
      end,
      group = group,
    })

    if m.config.navigation then
      vim.keymap.set("n", "n", function()
        m.NavigateToWord(true)
      end, { noremap = true, silent = true, desc = "InterestingWord Navigation Forward" })
      vim.keymap.set("n", "N", m.NavigateToWord,
        { noremap = true, silent = true, desc = "InterestingWord Navigation Backword" })
    end

    if m.config.search_key then
      vim.keymap.set("n", m.config.search_key, function()
        m.InterestingWord("n", true)
      end, { noremap = true, silent = true, desc = "InterestingWord Toggle Search" })
      vim.keymap.set("x", m.config.search_key, function()
        m.InterestingWord("v", true)
      end, { noremap = true, silent = true, desc = "InterestingWord Toggle Search" })
      vim.keymap.set("n", m.config.cancel_search_key, function()
        m.UncolorAllWords(true)
      end, { noremap = true, silent = true, desc = "InterestingWord Unsearch" })
    end

    if m.config.color_key then
      vim.keymap.set("n", m.config.color_key, function()
        m.InterestingWord("n", false)
      end, { noremap = true, silent = true, desc = "InterestingWord Toggle Color" })
      vim.keymap.set("x", m.config.color_key, function()
        m.InterestingWord("v", false)
      end, { noremap = true, silent = true, desc = "InterestingWord Toggle Color" })
      vim.keymap.set("n", m.config.cancel_color_key, function()
        m.UncolorAllWords()
      end, { noremap = true, silent = true, desc = "InterestingWord Uncolor" })
    end

    if m.config.search_count then
      m.init_search_count()
    end
  end

  return m
end)()

interestingwords.setup({
  select_mode = "loop", -- or "random"
  scroll_center = false,
  search_key = "<leader>S",
  cancel_search_key = "<leader>C",
  color_key = "<leader>H",
  cancel_color_key = "<leader>C",
  colors = { "#ff5f5f", "#5fafff", "#afff5f", "#ffd75f" },
})