local M = {}

M.config = {
    notes_dir = vim.fn.expand('~/.nvimwiki')
}

function M.setup(opts)
    M.config = vim.tbl_extend('force', M.config, opts or {})
end

function M.follow_link()
    local line = vim.api.nvim_get_current_line()
    local wiki_link = line:match('%[%[([^%]]+)%]%]')
    local md_link = line:match('%[.-%]%(([^%)])%)')

    local link = wiki_link or md_link

    if not link then return end

    if not link:match('%.md$') then link = link .. '.md' end

    if not link:match('^/') and not link:match('^%.') then
        local current_dir = vim.fn.expand('%:p:h')
        local relative_path = current_dir .. '/' .. link
        
        -- if file exists, edit it in the buffer
        if vim.fn.filereadable(realative_path) then
            vim.cmd('edit' .. relative_path)
            return
        end

        -- need to create file

        target_path = M.config.notes_dir .. '/' .. link
    else
        target_path = link
    end

    local parent_dir = vim.fn.fnamemodify(target_path, ':h')
    if vim.fn.isdirectory(parent_dir) == 0 then
        vim.fn.mkdir(parent_dir, 'p')
    end

    vim.cmd('edit' .. link)
end

function M.smart_link()
    local line = vim.api.nvim_get_current_line()
    local col = vim.api.nvim_win_get_cursor(0)[2]
    
    local before = line:sub(1, col + 1)
    local after = line:sub(col + 1)

    local in_wiki_link = before:match('%[%[[^%]]*$') and after:match('^[^%]]*%]%]')
    local in_md_link = before:match('%([^%)]*$') and after:match('^[^%)]*%)')

    if in_wiki_link or in_md_link then
        M.follow_link()
    else
        local word = vim.fn.expand('<cWORD>')

        word = word:match('[%w_/%-]+')

        if word and word ~= '' then
            vim.cmd('normal! ciW[[' .. word .. ']]')
            vim.cmd('normal! F[')
            M.follow_link()
        end

    end
end


function M.setup_keymaps()
    vim.keymap.set('n', '<CR>', M.smart_link, { buffer = true, desc = "follow link"})
    vim.keymap.set('n', '<BS>', '<C-o>', { buffer = true, desc = "go back"})
end

return M