let $FZF_BIBTEX_CACHEDIR = 'PATH-TO-CACHE-DIR'
let $FZF_BIBTEX_SOURCES = 'PATH-TO-BIBTEX-FILE'

function! s:bibtex_cite_sink(lines)
    let r=system("bibtex-cite ", a:lines)
    execute ':normal! a' . r
endfunction

function! s:bibtex_markdown_sink(lines)
    let r=system("bibtex-markdown ", a:lines)
    execute ':normal! a' . r
endfunction

nnoremap <silent> <leader>c :call fzf#run({
                        \ 'source': 'bibtex-ls',
                        \ 'sink*': function('<sid>bibtex_cite_sink'),
                        \ 'up': '40%',
                        \ 'options': '--ansi --layout=reverse-list --multi --prompt "Cite> "'})<CR>

nnoremap <silent> <leader>m :call fzf#run({
                        \ 'source': 'bibtex-ls',
                        \ 'sink*': function('<sid>bibtex_markdown_sink'),
                        \ 'up': '40%',
                        \ 'options': '--ansi --layout=reverse-list --multi --prompt "Markdown> "'})<CR>

function! s:bibtex_cite_sink_insert(lines)
    let r=system("bibtex-cite ", a:lines)
    execute ':normal! a' . r
    call feedkeys('a', 'n')
endfunction

inoremap <silent> @@ <c-g>u<c-o>:call fzf#run({
                        \ 'source': 'bibtex-ls',
                        \ 'sink*': function('<sid>bibtex_cite_sink_insert'),
                        \ 'up': '40%',
                        \ 'options': '--ansi --layout=reverse-list --multi --prompt "Cite> "'})<CR>

function! Bibtex_ls()
  let bibfiles = (
      \ globpath('.', '*.bib', v:true, v:true) +
      \ globpath('..', '*.bib', v:true, v:true) +
      \ globpath('*/', '*.bib', v:true, v:true)
      \ )
  let bibfiles = join(bibfiles, ' ')
  let source_cmd = 'bibtex-ls '.bibfiles
  return source_cmd
endfunction

function! s:bibtex_cite_sink_insert(lines)
    let r=system("bibtex-cite ", a:lines)
    execute ':normal! a' . r
    call feedkeys('a', 'n')
endfunction

inoremap <silent> @@ <c-g>u<c-o>:call fzf#run({
                        \ 'source': Bibtex_ls(),
                        \ 'sink*': function('<sid>bibtex_cite_sink_insert'),
                        \ 'up': '40%',
                        \ 'options': '--ansi --layout=reverse-list --multi --prompt "Cite> "'})<CR>

-- default list of bibfiles
-- can be overriden by changing vim.b.bibfiles inside buffer
local default_bibfiles = {
    -- put your default bibfiles here
    }

-- default cache directory
-- uses neovim's stdpath to set up a cache - no need to fiddle with this
local cachedir = vim.fn.stdpath("state") .. "/fzf-bibtex/"

-- actions
local pandoc = function(selected, opts)
    local result = vim.fn.system('bibtex-cite', selected)
    vim.api.nvim_put({ result }, "c", false, true)
    if opts.fzf_bibtex.mode == "i" then
        vim.api.nvim_feedkeys("i", "n", true)
    end
end

local citet = function(selected, opts)
    local result = vim.fn.system('bibtex-cite -prefix="\\citet{" -postfix="}" -separator=","', selected)
    vim.api.nvim_put({ result }, "c", false, true)
    if opts.fzf_bibtex.mode == "i" then
        vim.api.nvim_feedkeys("i", "n", true)
    end
end

local citep = function(selected, opts)
    local result = vim.fn.system('bibtex-cite -prefix="\\citep{" -postfix="}" -separator=","', selected)
    vim.api.nvim_put({ result }, "c", false, true)
    if opts.fzf_bibtex.mode == "i" then
        vim.api.nvim_feedkeys("i", "n", true)
    end
end

local markdown_print = function(selected, opts)
    local result = vim.fn.system("bibtex-markdown -cache=" .. cachedir .. " " .. table.concat(vim.b.bibfiles, " "),
        selected)
    local result_lines = {}
    for line in result:gmatch('[^\n]+') do
        table.insert(result_lines, line)
    end
    vim.api.nvim_put(result_lines, "l", true, true)
    if opts.fzf_bibtex.mode == "i" then
        vim.api.nvim_feedkeys("i", "n", true)
    end
end

local fzf_bibtex_menu = function(mode)
    return function()
        -- check cache directory hasn't mysteriously disappeared
        if vim.fn.isdirectory(cachedir) == 0 then
            vim.fn.mkdir(cachedir, "p")
        end

        require 'fzf-lua'.config.set_action_helpstr(pandoc, "@-pandoc")
        require 'fzf-lua'.config.set_action_helpstr(citet, "\\citet{}")
        require 'fzf-lua'.config.set_action_helpstr(citep, "\\citep{}")
        require 'fzf-lua'.config.set_action_helpstr(markdown_print, "markdown-pretty-print")

        -- header line: the bibtex filenames
        local filenames = {}
        for i, fullpath in ipairs(vim.b.bibfiles) do
            filenames[i] = vim.fn.fnamemodify(fullpath, ":t")
        end
        local header = table.concat(filenames, "\\ ")

        -- set default action
        local default_action = nil
        if vim.bo.ft == "markdown" then
            default_action = pandoc
        elseif
            vim.bo.ft == "tex" then
            default_action = citet
        end

        -- run fzf
        return require 'fzf-lua'.fzf_exec(
            "bibtex-ls "
            .. "-cache=" .. cachedir .. " "
            .. table.concat(vim.b.bibfiles, " "), {
                actions = {
                        ['default'] = default_action,
                        ['alt-a'] = pandoc,
                        ['alt-t'] = citet,
                        ['alt-p'] = citep,
                        ['alt-m'] = markdown_print,
                },
                fzf_bibtex = { ['mode'] = mode },
                fzf_opts = { ['--prompt'] = 'BibTeX> ',['--header'] = header }
            })
    end
end

-- Only enable mapping in tex or markdown
vim.api.nvim_create_autocmd("Filetype", {
    desc = "Set up keymaps for fzf-bibtex",
    group = vim.api.nvim_create_augroup("fzf-bibtex", { clear = true }),
    pattern = { "markdown", "tex" },
    callback = function()
        vim.b.bibfiles = default_bibfiles
        vim.keymap.set("n", "<leader>c", fzf_bibtex_menu("n"), { buffer = true, desc = "FZF: BibTeX [C]itations" })
        vim.keymap.set("i", "@@", fzf_bibtex_menu("i"), { buffer = true, desc = "FZF: BibTeX [C]itations" })
    end
})