-- Copyright 2026 Artur Ugnivenko. See LICENSE.
-- Odin LPeg lexer.

-- References:
-- https://odin-lang.org/spec/grammar/
-- https://pkg.odin-lang.org/base/builtin/

local lexer = lexer
local P, S = lpeg.P, lpeg.S

local lex = lexer.new(...)

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

-- Types.
lex:add_rule('type', lex:tag(lexer.TYPE, lex:word_match(lexer.TYPE)))

-- Functions.
local builtin_func = -lpeg.B('.') *
	lex:tag(lexer.FUNCTION_BUILTIN, lex:word_match(lexer.FUNCTION_BUILTIN))
local func = lex:tag(lexer.FUNCTION, lexer.word)
lex:add_rule('function', (builtin_func + func) * #P('('))

-- Constants.
lex:add_rule('constant', lex:tag(lexer.CONSTANT_BUILTIN, lex:word_match(lexer.CONSTANT_BUILTIN)))

-- Variables.
lex:add_rule('variable', lex:word_match(lexer.VARIABLE_BUILTIN))

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

-- Strings.
local sq_str = lexer.range("'")
local dq_str = lexer.range('"')
local raw_str = lexer.range('`')
lex:add_rule('string', lex:tag(lexer.STRING, P('L')^-1 * (sq_str + dq_str + raw_str)))

-- Comments.
local comment = lexer.to_eol(P('//') + '#!', true)
local block_comment = lexer.range('/*', '*/', false, false, true)
local file_tag = lexer.to_eol('#+')
lex:add_rule('comment', lex:tag(lexer.COMMENT, comment + block_comment + file_tag))

-- Directives.
lex:add_rule('directive', lex:tag(lexer.PREPROCESSOR, '#' * S(' \t')^0 * lexer.word))

-- Attributes.
lex:add_rule('attribute', lex:tag(lexer.PREPROCESSOR, '@' * lexer.word^-1))

-- Numbers.
lex:add_rule('number', lex:tag(lexer.NUMBER, lexer.number * S('ijk')^-1))

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

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

-- Word lists.
lex:set_word_list(lexer.KEYWORD, {
	'asm', 'auto_cast', 'bit_field', 'bit_set', 'break', 'case', 'cast', 'continue', 'defer',
	'distinct', 'do', 'dynamic', 'else', 'fallthrough', 'for', 'foreign', 'if', 'import', 'in', 'map',
	'matrix', 'not_in', 'of_break', 'or_continue', 'or_else', 'or_return', 'package', 'proc',
	'return', 'switch', 'transmute', 'typeid', 'using', 'when', 'where', 'enum', 'struct', 'union'
})

lex:set_word_list(lexer.TYPE, {
	'any', 'b8', 'b16', 'b32', 'b64', 'bool', 'byte', 'complex32', 'complex64', 'complex128',
	'cstring', 'cstring16', 'f16', 'f16le', 'f16be', 'f32', 'f32le', 'f32be', 'f64', 'f64le', 'f64be',
	'i8', 'i16', 'i16le', 'i16be', 'i32', 'i32le', 'i32be', 'i64', 'i64le', 'i64be', 'int',
	'quaternion64', 'quaternion128', 'quaternion256', 'rawptr', 'rune', 'string', 'string16',
	'typeid', 'u8', 'u16', 'u16le', 'u16be', 'u32', 'u32le', 'u32be', 'u64', 'u64le', 'u64be', 'uint',
	'uintptr'
})

lex:set_word_list(lexer.FUNCTION_BUILTIN, {
	'abs', 'align_of', 'cap', 'clamp', 'complex', 'compress_values', 'conj', 'expand_values', 'imag',
	'jmag', 'kmag', 'len', 'max', 'min', 'offset_of', 'offset_of_by_string', 'offset_of_member',
	'offset_of_selector', 'quaternion', 'raw_data', 'real', 'size_of', 'soa_unzip', 'soa_zip',
	'swizzle', 'type_info_of', 'type_of', 'typeid_of'
})

lex:set_word_list(lexer.CONSTANT_BUILTIN, {
	'false', 'true', 'nil', 'ODIN_ARCH', 'ODIN_BUILD_MODE', 'ODIN_COMPILE_TIMESTAMP', 'ODIN_DEBUG',
	'ODIN_DEFAULT_TO_NIL_ALLOCATOR', 'ODIN_DEFAULT_TO_PANIC_ALLOCATOR', 'ODIN_DISABLE_ASSERT',
	'ODIN_ENDIAN', 'ODIN_ERROR_POS_STYLE', 'ODIN_NO_CRT', 'ODIN_NO_ENTRY_POINT', 'ODIN_NO_RTTI',
	'ODIN_OS', 'ODIN_PLATFORM_SUBTARGET', 'ODIN_ROOT', 'ODIN_VENDOR', 'ODIN_VERSION',
	'ODIN_WINDOWS_SUBSYSTEM'
})

lex:set_word_list(lexer.VARIABLE_BUILTIN, {
	'context', 'runtime'
})

return lex