local core = require "fzf-lua.core"
local utils = require "fzf-lua.utils"
local shell = require "fzf-lua.shell"
local config = require "fzf-lua.config"
local actions = require "fzf-lua.actions"

local M = {}

M.commands = function(opts)

  opts = config.normalize_opts(opts, config.globals.nvim.commands)
  if not opts then return end

  local commands = vim.api.nvim_get_commands {}

  local prev_act = shell.action(function (args)
    local cmd = args[1]
    if commands[cmd] then
      cmd = vim.inspect(commands[cmd])
    end
    return cmd
  end)

  local entries = {}
  for k, _ in pairs(commands) do
    table.insert(entries, utils.ansi_codes.magenta(k))
  end

  table.sort(entries, function(a, b) return a<b end)

  opts.fzf_opts['--no-multi'] = ''
  opts.fzf_opts['--preview'] = prev_act

  core.fzf_wrap(opts, entries, function(selected)

    if not selected then return end
    actions.act(opts.actions, selected)

  end)()

end

local history = function(opts, str)

  local history = vim.fn.execute("history " .. str)
  history = vim.split(history, "\n")

  local entries = {}
  for i = #history, 3, -1 do
    local item = history[i]
    local _, finish = string.find(item, "%d+ +")
    table.insert(entries, string.sub(item, finish + 1))
  end

  opts.fzf_opts['--no-multi'] = ''
  opts.fzf_opts['--preview-window'] = 'hidden:right:0'

  core.fzf_wrap(opts, entries, function(selected)

    if not selected then return end
    actions.act(opts.actions, selected)

  end)()
end

local arg_header = function(sel_key, edit_key, text)
  sel_key = utils.ansi_codes.yellow(sel_key)
  edit_key = utils.ansi_codes.yellow(edit_key)
  return vim.fn.shellescape((':: %s to %s, %s to edit')
    :format(sel_key, text, edit_key))
end

M.command_history = function(opts)
  opts = config.normalize_opts(opts, config.globals.nvim.command_history)
  if not opts then return end
  opts.fzf_opts['--header'] = arg_header("<CR>", "<Ctrl-e>", "execute")
  history(opts, "cmd")
end

M.search_history = function(opts)
  opts = config.normalize_opts(opts, config.globals.nvim.search_history)
  if not opts then return end
  opts.fzf_opts['--header'] = arg_header("<CR>", "<Ctrl-e>", "search")
  history(opts, "search")
end

M.changes = function(opts)
  opts = opts or {}
  opts.cmd = "changes"
  opts.prompt = opts.prompt or "Changes> "
  return M.jumps(opts)
end

M.jumps = function(opts)
  opts = config.normalize_opts(opts, config.globals.nvim.jumps)
  if not opts then return end

  local jumps = vim.fn.execute(opts.cmd)
  jumps = vim.split(jumps, "\n")

  local entries = {}
  for i = #jumps-1, 3, -1 do
    local jump, line, col, text = jumps[i]:match("(%d+)%s+(%d+)%s+(%d+)%s+(.*)")
    if not jump then print(i, jumps[i]) end
    table.insert(entries, string.format("%-15s %-15s %-15s %s",
      utils.ansi_codes.yellow(jump),
      utils.ansi_codes.blue(line),
      utils.ansi_codes.green(col),
      text))
  end

  opts.fzf_opts['--no-multi'] = ''

  core.fzf_wrap(opts, entries, function(selected)

    if not selected then return end
    actions.act(opts.actions, selected, opts)

  end)()
end

M.marks = function(opts)
  opts = config.normalize_opts(opts, config.globals.nvim.marks)
  if not opts then return end

  local marks = vim.fn.execute("marks")
  marks = vim.split(marks, "\n")

  local prev_act = shell.action(function (args, fzf_lines, _)
    local mark = args[1]:match("[^ ]+")
    local bufnr, lnum, _, _ = unpack(vim.fn.getpos("'"..mark))
    if vim.api.nvim_buf_is_loaded(bufnr) then
      return vim.api.nvim_buf_get_lines(bufnr, lnum, fzf_lines+lnum, false)
    else
      local name = vim.fn.expand(args[1]:match(".* (.*)"))
      if vim.fn.filereadable(name) ~= 0 then
        return vim.fn.readfile(name, "", fzf_lines)
      end
      return "UNLOADED: " .. name
    end
  end)

  local entries = {}
  for i = #marks, 3, -1 do
    local mark, line, col, text = marks[i]:match("(.)%s+(%d+)%s+(%d+)%s+(.*)")
    table.insert(entries, string.format("%-15s %-15s %-15s %s",
      utils.ansi_codes.yellow(mark),
      utils.ansi_codes.blue(line),
      utils.ansi_codes.green(col),
      text))
  end

  table.sort(entries, function(a, b) return a<b end)

  opts.fzf_opts['--preview'] = prev_act
  opts.fzf_opts['--no-multi'] = ''

  core.fzf_wrap(opts, entries, function(selected)

    if not selected then return end
    actions.act(opts.actions, selected)

  end)()
end

M.registers = function(opts)

  opts = config.normalize_opts(opts, config.globals.nvim.registers)
  if not opts then return end

  local registers = { '"', "_", "#", "=", "_", "/", "*", "+", ":", ".", "%" }
  -- named
  for i = 0, 9 do
    table.insert(registers, tostring(i))
  end
  -- alphabetical
  for i = 65, 90 do
    table.insert(registers, string.char(i))
  end

  local prev_act = shell.action(function (args)
    local r = args[1]:match("%[(.*)%] ")
    local _, contents = pcall(vim.fn.getreg, r)
    return contents or args[1]
  end)

  local entries = {}
  for _, r in ipairs(registers) do
    -- pcall as this could fail with:
    -- E5108: Error executing lua Vim:clipboard:
    --        provider returned invalid data
    local _, contents = pcall(vim.fn.getreg, r)
    contents = contents:gsub("\n", utils.ansi_codes.magenta("\\n"))
    if (contents and #contents > 0) or not opts.ignore_empty then
      table.insert(entries, string.format("[%s] %s",
        utils.ansi_codes.yellow(r), contents))
    end
  end

  opts.fzf_opts['--no-multi'] = ''
  opts.fzf_opts['--preview'] = prev_act

  core.fzf_wrap(opts, entries, function(selected)

    if not selected then return end
    actions.act(opts.actions, selected)

  end)()
end

M.keymaps = function(opts)

  opts = config.normalize_opts(opts, config.globals.nvim.keymaps)
  if not opts then return end

  local modes = { "n", "i", "c" }
  local keymaps = {}

  local add_keymap = function(keymap)
    -- hijack fields
    keymap.str = string.format("[%s:%s:%s]",
      utils.ansi_codes.yellow(tostring(keymap.buffer)),
      utils.ansi_codes.green(keymap.mode),
      utils.ansi_codes.magenta(keymap.lhs:gsub("%s", "<Space>")))
    local k = string.format("[%s:%s:%s]",
      keymap.buffer, keymap.mode, keymap.lhs)
    keymaps[k] = keymap
  end

  for _, mode in pairs(modes) do
    local global = vim.api.nvim_get_keymap(mode)
    for _, keymap in pairs(global) do
      add_keymap(keymap)
    end
    local buf_local = vim.api.nvim_buf_get_keymap(0, mode)
    for _, keymap in pairs(buf_local) do
      add_keymap(keymap)
    end
  end

  local prev_act = shell.action(function (args)
    local k = args[1]:match("(%[.*%]) ")
    local v = keymaps[k]
    if v then
      -- clear hijacked field
      v.str = nil
      k = vim.inspect(v)
    end
    return k
  end)

  local entries = {}
  for _, v in pairs(keymaps) do
    table.insert(entries, string.format("%-50s %s",
    v.str, v.rhs))
  end

  opts.fzf_opts['--no-multi'] = ''
  opts.fzf_opts['--preview'] = prev_act

  core.fzf_wrap(opts, entries, function(selected)

    if not selected then return end
    actions.act(opts.actions, selected)

  end)()
end

M.spell_suggest = function(opts)

  -- if not vim.wo.spell then return false end
  opts = config.normalize_opts(opts, config.globals.nvim.spell_suggest)
  if not opts then return end

  local cursor_word = vim.fn.expand "<cword>"
  local entries = vim.fn.spellsuggest(cursor_word)

  if vim.tbl_isempty(entries) then return end

  opts.fzf_opts['--no-multi'] = ''
  opts.fzf_opts['--preview-window'] = 'hidden:right:0'

  core.fzf_wrap(opts, entries, function(selected)

    if not selected then return end
    actions.act(opts.actions, selected)

  end)()

end

M.filetypes = function(opts)

  opts = config.normalize_opts(opts, config.globals.nvim.filetypes)
  if not opts then return end

  local entries = vim.fn.getcompletion('', 'filetype')
  if vim.tbl_isempty(entries) then return end

  opts.fzf_opts['--no-multi'] = ''
  opts.fzf_opts['--preview-window'] = 'hidden:right:0'

  core.fzf_wrap(opts, entries, function(selected)

    if not selected then return end
    actions.act(opts.actions, selected)

  end)()

end

M.packadd = function(opts)

  opts = config.normalize_opts(opts, config.globals.nvim.packadd)
  if not opts then return end

  local entries = vim.fn.getcompletion('', 'packadd')

  if vim.tbl_isempty(entries) then return end

  opts.fzf_opts['--no-multi'] = ''
  opts.fzf_opts['--preview-window'] = 'hidden:right:0'

  core.fzf_wrap(opts, entries, function(selected)

    if not selected then return end
    actions.act(opts.actions, selected)

  end)()

end

return M