local M = {}

function M.create_link()
  local files = require('muwiki.files')
  local config = require('muwiki.config')

  local mode = vim.fn.mode()
  if mode ~= 'v' and mode ~= 'V' then
    vim.notify('Must be in visual mode to create a link', vim.log.levels.WARN)
    return
  end

  local start_pos = vim.fn.getpos('v')
  local end_pos = vim.fn.getpos('.')
  local region = vim.fn.getregion(start_pos, end_pos, { type = mode })

  if not region or #region == 0 then
    vim.notify('No text selected', vim.log.levels.WARN)
    return
  end

  if #region > 1 then
    vim.notify('Multi-line selection not supported', vim.log.levels.WARN)
    return
  end

  local selected_text = region[1]
  local normalized = files.normalize_filename(selected_text)
  local link_target = normalized .. '.md'
  local link_text = string.format('[%s](%s)', selected_text, link_target)

  local start_row = start_pos[2]
  local start_col = start_pos[3]
  local end_row = end_pos[2]
  local end_col = end_pos[3]

  if start_row > end_row or (start_row == end_row and start_col > end_col) then
    start_row, end_row = end_row, start_row
    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 mode == 'V' then
    start_col = 0
    local line = vim.api.nvim_buf_get_lines(0, end_row, end_row + 1, false)[1]
    end_col = #line
  end

  vim.api.nvim_buf_set_text(0, start_row, start_col, end_row, end_col, { link_text })
  vim.api.nvim_feedkeys(vim.api.nvim_replace_termcodes('<Esc>', true, false, true), 'n', false)

  local wiki_root = config.get_wiki_root_for_file(vim.api.nvim_buf_get_name(0))
  if not wiki_root then
    vim.notify('Not in a wiki buffer', vim.log.levels.ERROR)
    return
  end

  local target_path = files.resolve(link_target, wiki_root)
  files.open_wiki_file(target_path)
end

return M