-- Copyright 2006-2023 Mitchell. See LICENSE.
-- Lua LPeg lexer.
-- Original written by Peter Odding, 2007/04/04.
local lexer = lexer
local B, P, S = lpeg.B, lpeg.P, lpeg.S

local lex = lexer.new(...)

-- Keywords.
lex:add_rule('keyword', lex:tag(lexer.KEYWORD, lex:word_match(lexer.KEYWORD)))

-- Functions.
local non_field = -B('.') + B('_G.') + B('..')
local builtin_func = lex:word_match(lexer.FUNCTION_BUILTIN)
local lib_func = lex:word_match(lexer.FUNCTION_BUILTIN .. '.library')
local func = lex:tag(lexer.FUNCTION, lexer.word)
local method = B(':') * lex:tag(lexer.FUNCTION_METHOD, lexer.word)
lex:add_rule('function', method +
                 ((non_field *
                     lex:tag(lexer.FUNCTION_BUILTIN, builtin_func + lib_func)) +
                     func) * #(lexer.space ^ 0 * S('({\'"')))

-- Constants.
local builtin_const = lex:word_match(lexer.CONSTANT_BUILTIN)
local lib_const = lex:word_match(lexer.CONSTANT_BUILTIN .. '.library')
lex:add_rule('constant', non_field *
                 lex:tag(lexer.CONSTANT_BUILTIN, builtin_const + lib_const))

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

-- Strings.
local sq_str = lexer.range("'")
local dq_str = lexer.range('"')
local longstring = lpeg.Cmt('[' * lpeg.C(P('=') ^ 0) * '[',
                            function(input, index, eq)
    local _, e = input:find(']' .. eq .. ']', index, true)
    return (e or #input) + 1
end)
lex:add_rule('string', lex:tag(lexer.STRING, sq_str + dq_str) +
                 lex:tag(lexer.STRING .. '.longstring', longstring))

-- Comments.
local line_comment = lexer.to_eol('--')
local block_comment = '--' * longstring
lex:add_rule('comment', lex:tag(lexer.COMMENT, block_comment + line_comment))

-- Numbers.
local lua_integer = P('-') ^ -1 * (lexer.hex_num + lexer.dec_num)
lex:add_rule('number', lex:tag(lexer.NUMBER, lexer.float + lua_integer))

-- Labels.
lex:add_rule('label', lex:tag(lexer.LABEL, '::' * lexer.word * '::'))

-- Attributes.
lex:add_rule('attribute', lex:tag(lexer.ATTRIBUTE, '<' * lexer.space ^ 0 *
                                      lexer.word_match('const close') *
                                      lexer.space ^ 0 * '>'))

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

-- Fold points.
local function fold_longcomment(text, pos, line, s, symbol)
    if symbol == '[' then
        if line:find('^%[=*%[', s) then return 1 end
    elseif symbol == ']' then
        if line:find('^%]=*%]', s) then return -1 end
    end
    return 0
end
lex:add_fold_point(lexer.KEYWORD, 'if', 'end')
lex:add_fold_point(lexer.KEYWORD, 'do', 'end')
lex:add_fold_point(lexer.KEYWORD, 'function', 'end')
lex:add_fold_point(lexer.KEYWORD, 'repeat', 'until')
lex:add_fold_point(lexer.COMMENT, '[', fold_longcomment)
lex:add_fold_point(lexer.COMMENT, ']', fold_longcomment)
lex:add_fold_point(lexer.FUNCTION .. '.longstring', '[', ']')
lex:add_fold_point(lexer.OPERATOR, '(', ')')
lex:add_fold_point(lexer.OPERATOR, '[', ']')
lex:add_fold_point(lexer.OPERATOR, '{', '}')

-- Word lists.
lex:set_word_list(lexer.KEYWORD, {
    'and', 'break', 'do', 'else', 'elseif', 'end', 'false', 'for', 'function',
    'if', 'in', 'local', 'or', 'nil', 'not', 'repeat', 'return', 'then', 'true',
    'until', 'while', --
    'goto' -- 5.2
})

lex:set_word_list(lexer.FUNCTION_BUILTIN, {
    'assert', 'collectgarbage', 'dofile', 'error', 'getmetatable', 'ipairs',
    'load', 'loadfile', 'next', 'pairs', 'pcall', 'print', 'rawequal', 'rawget',
    'rawset', 'require', 'select', 'setmetatable', 'tonumber', 'tostring',
    'type', 'xpcall', --
    'rawlen', -- 5.2
    'warn' -- 5.4
})

lex:set_word_list(lexer.FUNCTION_BUILTIN .. '.library', {
    'coroutine.create', 'coroutine.resume', 'coroutine.running',
    'coroutine.status', 'coroutine.wrap', 'coroutine.yield', --
    'coroutine.isyieldable', -- 5.3
    'coroutine.close', -- 5.4
    'package.loadlib', --
    'package.searchpath', -- 5.2
    'utf8.char', 'utf8.codepoint', 'utf8.codes', 'utf8.len', 'utf8.offset', -- 5.3
    'string.byte', 'string.char', 'string.dump', 'string.find', 'string.format',
    'string.gmatch', 'string.gsub', 'string.len', 'string.lower',
    'string.match', 'string.rep', 'string.reverse', 'string.sub',
    'string.upper', --
    'string.pack', 'string.packsize', 'string.unpack', -- 5.3
    'table.concat', 'table.insert', 'table.remove', 'table.sort', --
    'table.pack', 'table.unpack', -- 5.2
    'table.move', -- 5.3
    'math.abs', 'math.acos', 'math.asin', 'math.atan', 'math.ceil', 'math.cos',
    'math.deg', 'math.exp', 'math.floor', 'math.fmod', 'math.log', 'math.max',
    'math.min', 'math.modf', 'math.rad', 'math.random', 'math.randomseed',
    'math.sin', 'math.sqrt', 'math.tan', --
    'math.tointeger', 'math.type', 'math.ult', -- 5.3
    'io.close', 'io.flush', 'io.input', 'io.lines', 'io.open', 'io.output',
    'io.popen', 'io.read', 'io.tmpfile', 'io.type', 'io.write', --
    'os.clock', 'os.date', 'os.difftime', 'os.execute', 'os.exit', 'os.getenv',
    'os.remove', 'os.rename', 'os.setlocale', 'os.time', 'os.tmpname', --
    'debug', 'debug.debug', 'debug.gethook', 'debug.getinfo', 'debug.getlocal',
    'debug.getmetatable', 'debug.getregistry', 'debug.getupvalue',
    'debug.sethook', 'debug.setlocal', 'debug.setmetatable', 'debug.setupvalue',
    'debug.traceback', --
    'debug.getuservalue', 'debug.setuservalue', 'debug.upvalueid',
    'debug.upvaluejoin' -- 5.2
})

lex:set_word_list(lexer.CONSTANT_BUILTIN, {
    '_G', '_VERSION', --
    '_ENV' -- 5.2
})

lex:set_word_list(lexer.CONSTANT_BUILTIN .. '.library', {
    'coroutine', --
    'package', 'package.cpath', 'package.loaded', 'package.path',
    'package.preload', --
    'package.config', 'package.searchers', -- 5.2
    'utf8', 'utf8.charpattern', -- 5.3
    'string', --
    'table', --
    'math', 'math.huge', 'math.pi', --
    'math.maxinteger', 'math.mininteger', -- 5.3
    'io', 'io.stderr', 'io.stdin', 'io.stdout', --
    'os'
})

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

return lex
