package scanner

import (
	"bufio"
	"bytes"
	"go/token"
	"io"
	"unicode"

	"github.com/cznic/golex/lex"
	"github.com/z7zmey/php-parser/comment"
	t "github.com/z7zmey/php-parser/token"
)

// Allocate Character classes anywhere in [0x80, 0xFF].
const (
	classUnicodeLeter = iota + 0x80
	classUnicodeDigit
	classUnicodeGraphic
	classOther
)

// T_INCLUDE token
const T_INCLUDE = 57346
// T_INCLUDE_ONCE token
const T_INCLUDE_ONCE = 57347
// T_EXIT token
const T_EXIT = 57348
// T_IF token
const T_IF = 57349
// T_LNUMBER token
const T_LNUMBER = 57350
// T_DNUMBER token
const T_DNUMBER = 57351
// T_STRING token
const T_STRING = 57352
// T_STRING_VARNAME token
const T_STRING_VARNAME = 57353
// T_VARIABLE token
const T_VARIABLE = 57354
// T_NUM_STRING token
const T_NUM_STRING = 57355
// T_INLINE_HTML token
const T_INLINE_HTML = 57356
// T_CHARACTER token
const T_CHARACTER = 57357
// T_BAD_CHARACTER token
const T_BAD_CHARACTER = 57358
// T_ENCAPSED_AND_WHITESPACE token
const T_ENCAPSED_AND_WHITESPACE = 57359
// T_CONSTANT_ENCAPSED_STRING token
const T_CONSTANT_ENCAPSED_STRING = 57360
// T_ECHO token
const T_ECHO = 57361
// T_DO token
const T_DO = 57362
// T_WHILE token
const T_WHILE = 57363
// T_ENDWHILE token
const T_ENDWHILE = 57364
// T_FOR token
const T_FOR = 57365
// T_ENDFOR token
const T_ENDFOR = 57366
// T_FOREACH token
const T_FOREACH = 57367
// T_ENDFOREACH token
const T_ENDFOREACH = 57368
// T_DECLARE token
const T_DECLARE = 57369
// T_ENDDECLARE token
const T_ENDDECLARE = 57370
// T_AS token
const T_AS = 57371
// T_SWITCH token
const T_SWITCH = 57372
// T_ENDSWITCH token
const T_ENDSWITCH = 57373
// T_CASE token
const T_CASE = 57374
// T_DEFAULT token
const T_DEFAULT = 57375
// T_BREAK token
const T_BREAK = 57376
// T_CONTINUE token
const T_CONTINUE = 57377
// T_GOTO token
const T_GOTO = 57378
// T_FUNCTION token
const T_FUNCTION = 57379
// T_CONST token
const T_CONST = 57380
// T_RETURN token
const T_RETURN = 57381
// T_TRY token
const T_TRY = 57382
// T_CATCH token
const T_CATCH = 57383
// T_FINALLY token
const T_FINALLY = 57384
// T_THROW token
const T_THROW = 57385
// T_USE token
const T_USE = 57386
// T_INSTEADOF token
const T_INSTEADOF = 57387
// T_GLOBAL token
const T_GLOBAL = 57388
// T_VAR token
const T_VAR = 57389
// T_UNSET token
const T_UNSET = 57390
// T_ISSET token
const T_ISSET = 57391
// T_EMPTY token
const T_EMPTY = 57392
// T_HALT_COMPILER token
const T_HALT_COMPILER = 57393
// T_CLASS token
const T_CLASS = 57394
// T_TRAIT token
const T_TRAIT = 57395
// T_INTERFACE token
const T_INTERFACE = 57396
// T_EXTENDS token
const T_EXTENDS = 57397
// T_IMPLEMENTS token
const T_IMPLEMENTS = 57398
// T_OBJECT_OPERATOR token
const T_OBJECT_OPERATOR = 57399
// T_DOUBLE_ARROW token
const T_DOUBLE_ARROW = 57400
// T_LIST token
const T_LIST = 57401
// T_ARRAY token
const T_ARRAY = 57402
// T_CALLABLE token
const T_CALLABLE = 57403
// T_CLASS_C token
const T_CLASS_C = 57404
// T_TRAIT_C token
const T_TRAIT_C = 57405
// T_METHOD_C token
const T_METHOD_C = 57406
// T_FUNC_C token
const T_FUNC_C = 57407
// T_LINE token
const T_LINE = 57408
// T_FILE token
const T_FILE = 57409
// T_COMMENT token
const T_COMMENT = 57410
// T_DOC_COMMENT token
const T_DOC_COMMENT = 57411
// T_OPEN_TAG token
const T_OPEN_TAG = 57412
// T_OPEN_TAG_WITH_ECHO token
const T_OPEN_TAG_WITH_ECHO = 57413
// T_CLOSE_TAG token
const T_CLOSE_TAG = 57414
// T_WHITESPACE token
const T_WHITESPACE = 57415
// T_START_HEREDOC token
const T_START_HEREDOC = 57416
// T_END_HEREDOC token
const T_END_HEREDOC = 57417
// T_DOLLAR_OPEN_CURLY_BRACES token
const T_DOLLAR_OPEN_CURLY_BRACES = 57418
// T_CURLY_OPEN token
const T_CURLY_OPEN = 57419
// T_PAAMAYIM_NEKUDOTAYIM token
const T_PAAMAYIM_NEKUDOTAYIM = 57420
// T_NAMESPACE token
const T_NAMESPACE = 57421
// T_NS_C token
const T_NS_C = 57422
// T_DIR token
const T_DIR = 57423
// T_NS_SEPARATOR token
const T_NS_SEPARATOR = 57424
// T_ELLIPSIS token
const T_ELLIPSIS = 57425
// T_EVAL token
const T_EVAL = 57426
// T_REQUIRE token
const T_REQUIRE = 57427
// T_REQUIRE_ONCE token
const T_REQUIRE_ONCE = 57428
// T_LOGICAL_OR token
const T_LOGICAL_OR = 57429
// T_LOGICAL_XOR token
const T_LOGICAL_XOR = 57430
// T_LOGICAL_AND token
const T_LOGICAL_AND = 57431
// T_INSTANCEOF token
const T_INSTANCEOF = 57432
// T_NEW token
const T_NEW = 57433
// T_CLONE token
const T_CLONE = 57434
// T_ELSEIF token
const T_ELSEIF = 57435
// T_ELSE token
const T_ELSE = 57436
// T_ENDIF token
const T_ENDIF = 57437
// T_PRINT token
const T_PRINT = 57438
// T_YIELD token
const T_YIELD = 57439
// T_STATIC token
const T_STATIC = 57440
// T_ABSTRACT token
const T_ABSTRACT = 57441
// T_FINAL token
const T_FINAL = 57442
// T_PRIVATE token
const T_PRIVATE = 57443
// T_PROTECTED token
const T_PROTECTED = 57444
// T_PUBLIC token
const T_PUBLIC = 57445
// T_INC token
const T_INC = 57446
// T_DEC token
const T_DEC = 57447
// T_YIELD_FROM token
const T_YIELD_FROM = 57448
// T_INT_CAST token
const T_INT_CAST = 57449
// T_DOUBLE_CAST token
const T_DOUBLE_CAST = 57450
// T_STRING_CAST token
const T_STRING_CAST = 57451
// T_ARRAY_CAST token
const T_ARRAY_CAST = 57452
// T_OBJECT_CAST token
const T_OBJECT_CAST = 57453
// T_BOOL_CAST token
const T_BOOL_CAST = 57454
// T_UNSET_CAST token
const T_UNSET_CAST = 57455
// T_COALESCE token
const T_COALESCE = 57456
// T_SPACESHIP token
const T_SPACESHIP = 57457
// T_NOELSE token
const T_NOELSE = 57458
// T_PLUS_EQUAL token
const T_PLUS_EQUAL = 57459
// T_MINUS_EQUAL token
const T_MINUS_EQUAL = 57460
// T_MUL_EQUAL token
const T_MUL_EQUAL = 57461
// T_DIV_EQUAL token
const T_DIV_EQUAL = 57462
// T_CONCAT_EQUAL token
const T_CONCAT_EQUAL = 57463
// T_MOD_EQUAL token
const T_MOD_EQUAL = 57464
// T_AND_EQUAL token
const T_AND_EQUAL = 57465
// T_OR_EQUAL token
const T_OR_EQUAL = 57466
// T_XOR_EQUAL token
const T_XOR_EQUAL = 57467
// T_SL_EQUAL token
const T_SL_EQUAL = 57468
// T_SR_EQUAL token
const T_SR_EQUAL = 57469
// T_POW_EQUAL token
const T_POW_EQUAL = 57470
// T_BOOLEAN_OR token
const T_BOOLEAN_OR = 57471
// T_BOOLEAN_AND token
const T_BOOLEAN_AND = 57472
// T_IS_EQUAL token
const T_IS_EQUAL = 57473
// T_IS_NOT_EQUAL token
const T_IS_NOT_EQUAL = 57474
// T_IS_IDENTICAL token
const T_IS_IDENTICAL = 57475
// T_IS_NOT_IDENTICAL token
const T_IS_NOT_IDENTICAL = 57476
// T_IS_SMALLER_OR_EQUAL token
const T_IS_SMALLER_OR_EQUAL = 57477
// T_IS_GREATER_OR_EQUAL token
const T_IS_GREATER_OR_EQUAL = 57478
// T_SL token
const T_SL = 57479
// T_SR token
const T_SR = 57480
// T_POW token
const T_POW = 57481

// Lval parsers yySymType must implement this interface
type Lval interface {
	Token(tkn t.Token)
}

// Lexer php lexer
type Lexer struct {
	*lex.Lexer
	StateStack    []int
	PhpDocComment string
	Comments      []comment.Comment
}

// Rune2Class returns the rune integer id
func Rune2Class(r rune) int {
	if r >= 0 && r < 0x80 { // Keep ASCII as it is.
		return int(r)
	}
	if unicode.IsLetter(r) {
		return classUnicodeLeter
	}
	if unicode.IsDigit(r) {
		return classUnicodeDigit
	}
	if unicode.IsGraphic(r) {
		return classUnicodeGraphic
	}
	// return classOther
	return -1
}

// NewLexer the Lexer constructor
func NewLexer(src io.Reader, fName string) *Lexer {
	file := token.NewFileSet().AddFile(fName, -1, 1<<31-1)
	lx, err := lex.New(file, bufio.NewReader(src), lex.RuneClass(Rune2Class))
	if err != nil {
		panic(err)
	}
	return &Lexer{lx, []int{0}, "", nil}
}

func (l *Lexer) ungetChars(n int) []lex.Char {
	l.Unget(l.Lookahead())

	chars := l.Token()

	for i := 1; i <= n; i++ {
		char := chars[len(chars)-i]
		l.Unget(char)
	}

	buf := l.Token()
	buf = buf[:len(buf)-n]

	return buf
}

func (l *Lexer) pushState(state int) {
	l.StateStack = append(l.StateStack, state)
}

func (l *Lexer) popState() {
	len := len(l.StateStack)
	if len <= 1 {
		return
	}

	l.StateStack = l.StateStack[:len-1]
}

func (l *Lexer) begin(state int) {
	len := len(l.StateStack)
	l.StateStack = l.StateStack[:len-1]
	l.StateStack = append(l.StateStack, state)
}

func (l *Lexer) getCurrentState() int {
	return l.StateStack[len(l.StateStack)-1]
}

func (l *Lexer) newToken(chars []lex.Char) t.Token {
	firstChar := chars[0]
	lastChar := chars[len(chars)-1]

	startLine := l.File.Line(firstChar.Pos())
	endLine := l.File.Line(lastChar.Pos())
	startPos := int(firstChar.Pos())
	endPos := int(lastChar.Pos())

	return t.NewToken(l.charsToBytes(chars), startLine, endLine, startPos, endPos).SetComments(l.Comments)
}

func (l *Lexer) addComment(c comment.Comment) {
	l.Comments = append(l.Comments, c)
}

func (l *Lexer) charsToBytes(chars []lex.Char) []byte {
	bytesBuf := bytes.Buffer{}

	for _, c := range chars {
		bytesBuf.WriteRune(c.Rune)
	}

	return bytesBuf.Bytes()
}