-- Copyright 2015-2023 Mitchell. See LICENSE.
-- Contributed by Richard Philips.
-- Elixir LPeg lexer.
local lexer = require('lexer')
local token, word_match = lexer.token, lexer.word_match
local B, P, S = lpeg.B, lpeg.P, lpeg.S

local lex = lexer.new('elixir', {fold_by_indentation = true})

-- Whitespace.
lex:add_rule('whitespace', token(lexer.WHITESPACE, lexer.space ^ 1))

-- Sigils.
local sigil11 = '~' * S('CRSW') * lexer.range('<', '>')
local sigil12 = '~' * S('CRSW') * lexer.range('{', '}')
local sigil13 = '~' * S('CRSW') * lexer.range('[', ']')
local sigil14 = '~' * S('CRSW') * lexer.range('(', ')')
local sigil15 = '~' * S('CRSW') * lexer.range('|', false, false)
local sigil16 = '~' * S('CRSW') * lexer.range('/', false, false)
local sigil17 = '~' * S('CRSW') * lexer.range('"', false, false)
local sigil18 = '~' * S('CRSW') * lexer.range("'", false, false)
local sigil19 = '~' * S('CRSW') * lexer.range('"""')
local sigil10 = '~' * S('CRSW') * lexer.range("'''")
local sigil21 = '~' * S('crsw') * lexer.range('<', '>')
local sigil22 = '~' * S('crsw') * lexer.range('{', '}')
local sigil23 = '~' * S('crsw') * lexer.range('[', ']')
local sigil24 = '~' * S('crsw') * lexer.range('(', ')')
local sigil25 = '~' * S('crsw') * lexer.range('|')
local sigil26 = '~' * S('crsw') * lexer.range('/')
local sigil27 = '~' * S('crsw') * lexer.range('"')
local sigil28 = '~' * S('crsw') * lexer.range("'")
local sigil29 = '~' * S('crsw') * lexer.range('"""')
local sigil20 = '~' * S('crsw') * lexer.range("'''")
local sigil_token = token(lexer.REGEX,
                          sigil10 + sigil19 + sigil11 + sigil12 + sigil13 +
                              sigil14 + sigil15 + sigil16 + sigil17 + sigil18 +
                              sigil20 + sigil29 + sigil21 + sigil22 + sigil23 +
                              sigil24 + sigil25 + sigil26 + sigil27 + sigil28)
local sigiladdon_token = token(lexer.EMBEDDED, lexer.alpha ^ 0)
lex:add_rule('sigil', sigil_token * sigiladdon_token)

-- Atoms.
local atom1 = B(1 - P(':')) * ':' * lexer.range('"')
local atom2 = B(1 - P(':')) * ':' * lexer.alpha * (lexer.alnum + S('_@')) ^ 0 *
                  S('?!') ^ -1
local atom3 = B(1 - (lexer.alnum + S('_:'))) * lexer.upper *
                  (lexer.alnum + S('_@')) ^ 0 * S('?!') ^ -1
lex:add_rule('atom', token(lexer.CONSTANT, atom1 + atom2 + atom3))

-- Strings.
local dq_str = lexer.range('"')
local triple_dq_str = lexer.range('"""')
lex:add_rule('string', token(lexer.STRING, triple_dq_str + dq_str))

-- Comments.
lex:add_rule('comment', token(lexer.COMMENT, lexer.to_eol('#', true)))

-- Attributes.
lex:add_rule('attribute', token(lexer.LABEL, B(1 - (lexer.alnum + '_')) * '@' *
                                    lexer.alpha * (lexer.alnum + '_') ^ 0))

-- Booleans.
lex:add_rule('boolean',
             token(lexer.NUMBER, P(':') ^ -1 * word_match('true false nil')))

-- Functions.
lex:add_rule('function', token(lexer.FUNCTION, word_match {
    'defstruct', 'defrecordp', 'defrecord', 'defprotocol', 'defp',
    'defoverridable', 'defmodule', 'defmacrop', 'defmacro', 'defimpl',
    'defexception', 'defdelegate', 'defcallback', 'def'
}))

-- Keywords.
lex:add_rule('keyword', token(lexer.KEYWORD, word_match {
    'is_atom', 'is_binary', 'is_bitstring', 'is_boolean', 'is_float',
    'is_function', 'is_integer', 'is_list', 'is_map', 'is_number', 'is_pid',
    'is_port', 'is_record', 'is_reference', 'is_tuple', 'is_exception', 'case',
    'when', 'cond', 'for', 'if', 'unless', 'try', 'receive', 'send', 'exit',
    'raise', 'throw', 'after', 'rescue', 'catch', 'else', 'do', 'end', 'quote',
    'unquote', 'super', 'import', 'require', 'alias', 'use', 'self', 'with',
    'fn'
}))

-- Operators
local operator1 = word_match('and or not when xor in')
local operator2 = P('!==') + '!=' + '!' + '=~' + '===' + '==' + '=' + '<<<' +
                      '<<' + '<=' + '<-' + '<' + '>>>' + '>>' + '>=' + '>' +
                      '->' + '--' + '-' + '++' + '+' + '&&&' + '&&' + '&' +
                      '|||' + '||' + '|>' + '|' + '..' + '.' + '^^^' + '^' +
                      '\\\\' + '::' + '*' + '/' + '~~~' + '@'
lex:add_rule('operator', token(lexer.OPERATOR, operator1 + operator2))

-- Identifiers
lex:add_rule('identifier', token(lexer.IDENTIFIER, lexer.word * S('?!') ^ -1))

-- Numbers
local dec = lexer.digit * (lexer.digit + '_') ^ 0
local bin = '0b' * S('01') ^ 1
local oct = '0o' * lpeg.R('07') ^ 1
local integer = bin + lexer.hex_num + oct + dec
local float = lexer.digit ^ 1 * '.' * lexer.digit ^ 1 * S('eE') *
                  (S('+-') ^ -1 * lexer.digit ^ 1) ^ -1
lex:add_rule('number', B(1 - (lexer.alpha + '_')) * S('+-') ^ -1 *
                 token(lexer.NUMBER, float + integer))

lexer.property['scintillua.comment'] = '#'

return lex
