local ls = require 'luasnip'
local s = ls.snippet
local sn = ls.snippet_node
local isn = ls.indent_snippet_node
local t = ls.text_node
local i = ls.insert_node
local f = ls.function_node
local c = ls.choice_node
local d = ls.dynamic_node
local r = ls.restore_node
local events = require 'luasnip.util.events'
local ai = require 'luasnip.nodes.absolute_indexer'
local extras = require 'luasnip.extras'
local l = extras.lambda
local rep = extras.rep
local p = extras.partial
local m = extras.match
local n = extras.nonempty
local dl = extras.dynamic_lambda
local fmt = require('luasnip.extras.fmt').fmt
local fmta = require('luasnip.extras.fmt').fmta
local conds = require 'luasnip.extras.expand_conditions'
local postfix = require('luasnip.extras.postfix').postfix
local types = require 'luasnip.util.types'
local parse = require('luasnip.util.parser').parse_snippet
local ms = ls.multi_snippet
local k = require('luasnip.nodes.key_indexer').new_key

return {
  s({ trig = 'mod', name = 'Module', description = 'insert module with filename populated' }, {
    t '-module(',
    f(function(args, snip)
      local filename = snip.env.TM_FILENAME
      local rev = string.reverse(filename)
      local dot = string.find(rev, '.', 1, true)
      if dot == nil then
        return filename
      else
        return filename:sub(1, -(dot + 1))
      end
    end, {}),
    t ').',
  }),
  s({ trig = 'fn', name = 'function', description = 'new function' }, {
    i(1, 'function_name'),
    t '(',
    i(2),
    t { ') ->', '' },
    i(0),
    t '.',
  }),
  s({ trig = 'case', name = 'case statement', description = 'new case statement' }, {
    t 'case ',
    i(1),
    t { ' of', '' },
    i(2),
    t 'end',
  }),
  s({ trig = 'HT', name = 'list pattern', description = 'list pattern' }, {
    t '[ ',
    i(1, 'Head'),
    t ' | ',
    i(2, 'Tail'),
    t ' ]',
  }),
  s({ trig = 'tup', name = 'tuple pattern', description = 'tuple pattern' }, {
    t '{ ',
    i(1, 'Value'),
    t ' }',
  }),
  s({ trig = 'DOWN', name = 'Down message', description = 'down message for matching' }, {
    t "{'DOWN', Ref, process, Pid, Reason}",
  }),
  s({ trig = 'mexp', name = 'merge exports', description = 'merge multiple lines of exports into one' }, {
    t '-export([',
    f(function(_, snip)
      local all_exports = ''
      local is_first = true
      for _, line in ipairs(snip.env.LS_SELECT_RAW) do
        local exports = line:gsub('-export%(%[(.*)%]%).', '%1')
        if is_first then
          all_exports = all_exports .. exports
          is_first = false
        else
          all_exports = all_exports .. ',' .. exports
        end
      end
      return all_exports
    end, {}),
    t ']).',
  }),
  s({ trig = 'server', name = 'gen server template', description = 'create gen server outline' }, {
    t {
      '-behavoir(gen_server).',
      '-export([init/1, handle_call/3, handle_cast/2, handle_info/2, terminate/2, code_change/3]).',
      '',
      'init(State) ->',
      '\t{ok, State}.',
      '',
      'handle_call(_Event, _From, State) ->',
      '\t{noreply, State}.',
      '',
      'handle_cast(_Event, State) ->',
      '\t{noreply, State}.',
      '',
      'handle_info(_Event, State) ->',
      '\t{noreply, State}.',
      '',
      'terminate(_Reason, _State) ->',
      '\tok.',
      '',
      'code_change(_OldSvn, State, _Extra) ->',
      '\t{ok, State}.',
    },
  }),
}