local keymap = vim.keymap

-- Picker for markdown headers
local pickers = require("telescope.pickers")
local finders = require("telescope.finders")
local conf = require("telescope.config").values
local actions = require("telescope.actions")
local action_state = require("telescope.actions.state")

local function formatted_date()
  local current_date = os.date("%Y-%m-%d")
  if type(current_date) == "string" then
    vim.api.nvim_put({current_date}, 'c', true, true)
  end
end

local function formatted_datetime()
  local current_datetime = os.date("%Y-%m-%d %HH:%MM")
  if type(current_datetime) == "string" then
    vim.api.nvim_put({current_datetime}, 'c', true, true)
  end
end

local function markdown_headings()
  local bufnr = vim.api.nvim_get_current_buf()
  local lines = vim.api.nvim_buf_get_lines(bufnr, 0, -1, false)
  local headings = {}

  for lnum, line in ipairs(lines) do
    local heading = line:match('^(#+%s+.+)$')
    if heading then
      table.insert(headings, {
        lnum = lnum,
        text = heading,
        display = string.format("%4d: %s", lnum, heading)
      })
    end
  end
  pickers.new({}, {
    prompt_title = 'Markdown Headings',
    finder = finders.new_table {
      results = headings,
      entry_maker = function(entry)
        return {
          value = entry,
          display = entry.display,
          ordinal = entry.text,
          lnum = entry.lnum,
        }
      end
    },
    sorter = conf.generic_sorter({}),
    attach_mappings = function(prompt_bufnr, map)
      actions.select_default:replace(function()
        actions.close(prompt_bufnr)
        local selection = action_state.get_selected_entry()
        vim.api.nvim_win_set_cursor(0, {selection.value.lnum, 0})
      end)
      return true
    end,
  }):find()
end

keymap.set("n", "<leader>fdh", markdown_headings, { desc = "Grep: Markdown headings" })
keymap.set("n", "<leader>icd", formatted_date, { desc = "Insert current date" })
keymap.set("n", "<leader>ict", formatted_datetime, { desc = "Insert current datetime" })