-- Copyright (c) 2014-2023 Piotr Orzechowski [drzewo.org]. See LICENSE.
-- Xtend LPeg lexer.
local lexer = require('lexer')
local token, word_match = lexer.token, lexer.word_match
local P, S = lpeg.P, lpeg.S

local lex = lexer.new('xtend')

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

-- Classes.
lex:add_rule('class', token(lexer.KEYWORD, 'class') * ws ^ 1 *
                 token(lexer.CLASS, lexer.word))

-- Keywords.
lex:add_rule('keyword', token(lexer.KEYWORD, word_match {
    -- General.
    'abstract', 'annotation', 'as', 'case', 'catch', 'class', 'create', 'def',
    'default', 'dispatch', 'do', 'else', 'enum', 'extends', 'extension',
    'final', 'finally', 'for', 'if', 'implements', 'import', 'interface',
    'instanceof', 'it', 'new', 'override', 'package', 'private', 'protected',
    'public', 'return', 'self', 'static', 'super', 'switch', 'synchronized',
    'this', 'throw', 'throws', 'try', 'typeof', 'val', 'var', 'while',
    -- Templates.
    'AFTER', 'BEFORE', 'ENDFOR', 'ENDIF', 'FOR', 'IF', 'SEPARATOR',
    -- Literals.
    'true', 'false', 'null'
}))

-- Types.
lex:add_rule('type', token(lexer.TYPE, word_match {
    'boolean', 'byte', 'char', 'double', 'float', 'int', 'long', 'short',
    'void', 'Boolean', 'Byte', 'Character', 'Double', 'Float', 'Integer',
    'Long', 'Short', 'String'
}))

-- Functions.
lex:add_rule('function', token(lexer.FUNCTION, lexer.word) * #P('('))

-- Identifiers.
lex:add_rule('identifier', token(lexer.IDENTIFIER, lexer.word))

-- Templates.
lex:add_rule('template', token(lexer.EMBEDDED, lexer.range("'''")))

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

-- Comments.
local line_comment = lexer.to_eol('//', true)
local block_comment = lexer.range('/*', '*/')
lex:add_rule('comment', token(lexer.COMMENT, line_comment + block_comment))

-- Numbers.
local small_suff = S('lL')
local med_suff = S('bB') * S('iI')
local large_suff = S('dD') + S('fF') + S('bB') * S('dD')
local exp = S('eE') * lexer.digit ^ 1

local dec_inf = ('_' * lexer.digit ^ 1) ^ 0
local hex_inf = ('_' * lexer.xdigit ^ 1) ^ 0
local float_pref = lexer.digit ^ 1 * '.' * lexer.digit ^ 1
local float_suff = exp ^ -1 * med_suff ^ -1 * large_suff ^ -1

local dec = lexer.digit * dec_inf * (small_suff ^ -1 + float_suff)
local hex = lexer.hex_num * hex_inf * P('#' * (small_suff + med_suff)) ^ -1
local float = float_pref * dec_inf * float_suff

lex:add_rule('number', token(lexer.NUMBER, float + hex + dec))

-- Annotations.
lex:add_rule('annotation', token(lexer.ANNOTATION, '@' * lexer.word))

-- Operators.
lex:add_rule('operator', token(lexer.OPERATOR, S('+-/*%<>!=^&|?~:;.()[]{}#')))

-- Error.
lex:add_rule('error', token(lexer.ERROR, lexer.any))

-- Fold points.
lex:add_fold_point(lexer.OPERATOR, '{', '}')
lex:add_fold_point(lexer.COMMENT, '/*', '*/')

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

return lex
