local M = {}

local config = require("denote-fzf-lua.config")
local fzflua = require("fzf-lua")
local builtin = require("fzf-lua.previewer.builtin")

local FIELDS = { "path", "date", "time", "sig", "title", "keywords", "ext" }
local lua_dir = debug.getinfo(1, "S").source:match("@?(.*/)")
local script_dir = lua_dir .. "denote-fzf-lua/scripts/"

local function format_field(field, delim)
  if field == "." then return "" end
  return delim .. delim .. field:gsub("%s", delim)
end

function M.format_fzf_with_nth(options)
  local indices = {}
  for i, field in ipairs(FIELDS) do
    if options.search_fields[field] then
      table.insert(indices, i)
    end
  end
  return table.concat(indices, ",")
end

function M.has_prereqs(force_slow)
  if vim.fn.executable("fzf") ~= 1 then return "no" end
  if force_slow then return "partial" end
  for _, cmd in ipairs({ "fd", "sd", "qsv" }) do
    if vim.fn.executable(cmd) ~= 1 then return "partial" end
  end
  return "yes"
end

function M.get_script(force_slow)
  local prereqs = M.has_prereqs(force_slow)
  if prereqs == "no" then
    error("Missing dependency: fzf")
    return
  elseif prereqs == "yes" then
    return script_dir .. "search_files.sh"
  else
    return script_dir .. "fallback_search_files.sh"
  end
end

function M.reconstruct_filename(row)
  if not row or row == "" then return "" end
  row = row:gsub("%s+$", "")
  local parts = {}
  row = row:gsub("%s%s+", "|")
  parts.path, parts.year, parts.month, parts.day, parts.hour, parts.min, parts.sec, parts.sig, parts.title, parts.keywords, parts.ext =
    row:match("^(.*/)|(%d%d%d%d)%-(%d%d)%-(%d%d)|(%d%d):(%d%d):(%d%d)|([^|]+)|([^|]+)|([^|]+)|(%..+)")
  if not parts.path then return "" end
  local sig      = format_field(parts.sig, "=")
  local title    = format_field(parts.title, "-")
  local keywords = format_field(parts.keywords, "_")
  return parts.path .. parts.year .. parts.month .. parts.day .. "T" .. parts.hour .. parts.min .. parts.sec .. sig .. title .. keywords .. parts.ext
end

M.reconstruct_previewer = builtin.buffer_or_file:extend()

function M.reconstruct_previewer:new(o, opts, fzf_win)
  M.reconstruct_previewer.super.new(self, o, opts, fzf_win)
  setmetatable(self, M.reconstruct_previewer)
  return self
end

function M.reconstruct_previewer:parse_entry(entry_str)
  return {
    path = M.reconstruct_filename(entry_str),
    line = 1,
    col = 1,
  }
end

function M.search_files(options)
  local script = M.get_script(options.force_slow_mode)
  if not script then return end

  local opts = {}
  opts.previewer = M.reconstruct_previewer
  opts.fzf_opts = vim.deepcopy(options.fzf_lua_opts.fzf_opts)
  opts.fzf_opts["--with-nth"] = M.format_fzf_with_nth(options)
  opts.fzf_opts["--header-lines"] = 1
  opts.fzf_opts["--delimiter"] = "\\s{2,}"
  opts.actions = {
    default = function(selected)
      local filename = M.reconstruct_filename(selected[1])
      vim.api.nvim_command("edit " .. vim.fn.fnameescape(filename))
    end,
  }
  local dir = vim.fn.expand(vim.g.denote_dir or options.dir)
  fzflua.fzf_exec(script .. " " .. dir, opts)
end

function M.search_contents(options)
  if vim.fn.executable("rg") ~= 1 then
    vim.notify("denote-fzf-lua: ripgrep is required for content search", vim.log.levels.WARN)
    return
  end
  local opts = {}
  opts.cwd = vim.fn.expand(vim.g.denote_dir or options.dir)
  opts.previewer = "builtin"
  opts.fzf_opts = options.fzf_lua_opts.fzf_opts
  opts.actions = fzflua.defaults.actions.files
  fzflua.fzf_live(function(query)
    local q = type(query) == "table" and table.concat(query, " ") or query or ""
    return "rg --column --color=always -i -- " .. vim.fn.shellescape(q)
  end, opts)
end

function M.load_cmd(options)
  vim.api.nvim_create_user_command("DenoteSearch", function(opts)
    if opts.fargs[1] == "files" then
      M.search_files(options)
    elseif opts.fargs[1] == "contents" then
      M.search_contents(options)
    else
      error("Unsupported operation " .. opts.fargs[1])
    end
  end, {
    nargs = 1,
    complete = function()
      return { "files", "contents" }
    end,
  })
end

function M.setup(options)
  options = vim.tbl_deep_extend("force", config.defaults, options or {})
  fzflua.setup(options.fzf_lua_opts)
  M.load_cmd(options)
end

return M