// format parses src, prints the corresponding AST, verifies the resulting
// src is syntactically correct, and returns the resulting src or an error
// if any.
func format(src []byte, mode checkMode) ([]byte, error) {
	// parse src
	f, err := parser.ParseFile(fset, "", src, parser.ParseComments)
	if err != nil {
		return nil, fmt.Errorf("parse: %s\n%s", err, src)
	}

	// filter exports if necessary
	if mode&export != 0 {
		ast.FileExports(f) // ignore result
		f.Comments = nil   // don't print comments that are not in AST
	}

	// determine printer configuration
	cfg := Config{Tabwidth: tabwidth}
	if mode&rawFormat != 0 {
		cfg.Mode |= RawFormat
	}

	// print AST
	var buf bytes.Buffer
	if err := cfg.Fprint(&buf, fset, f); err != nil {
		return nil, fmt.Errorf("print: %s", err)
	}

	// make sure formatted output is syntactically correct
	res := buf.Bytes()
	if _, err := parser.ParseFile(fset, "", res, 0); err != nil {
		return nil, fmt.Errorf("re-parse: %s\n%s", err, buf.Bytes())
	}

	return res, nil
}

func doParseFiles(filePathes []string, fset *token.FileSet) (*token.FileSet, []*ast.File, error) {
	if fset == nil {
		fset = token.NewFileSet()
	}
	util.Info("parsing files %v", filePathes)
	astFiles := make([]*ast.File, 0, len(filePathes))
	for _, f := range filePathes {
		//XXX: Ignoring files with packages ends with _test.
		//XXX: Doing that because getting error in check()
		//XXX: cause source file is still going to current
		//XXX: packages. Need to analyze package before
		//XXX: and check both packages separately.
		tempFset := token.NewFileSet()
		astFile, err := parser.ParseFile(tempFset, f, nil, 0)
		if !strings.HasSuffix(astFile.Name.Name, "_test") {
			if err != nil {
				return nil, nil, err
			}
			astFile, _ := parser.ParseFile(fset, f, nil, 0)
			astFiles = append(astFiles, astFile)
		}
	}

	iterateFunc := func(f *token.File) bool {
		util.Debug("\t%s", f.Name())
		return true
	}
	fset.Iterate(iterateFunc)
	return fset, astFiles, nil
}

// Parse parses the source in filename and returns a list of tags.
func Parse(filename string) ([]Tag, error) {
	p := &tagParser{
		fset:  token.NewFileSet(),
		tags:  []Tag{},
		types: make([]string, 0),
	}

	var f *ast.File
	var err error

	if filename != "-" {
		f, err = parser.ParseFile(p.fset, filename, nil, 0)
		if err != nil {
			return nil, err
		}
	} else {
		bytes, err := ioutil.ReadAll(os.Stdin)

		f, err = parser.ParseFile(p.fset, "", string(bytes), 0)
		if err != nil {
			return nil, err
		}
	}

	// package
	p.parsePackage(f)

	// imports
	p.parseImports(f)

	// declarations
	p.parseDeclarations(f)

	return p.tags, nil
}

// NewParser creates a new Parser reference from the given options
func NewParser(opts *ParserOptions) (*Parser, error) {
	var mode parser.Mode
	if opts != nil && opts.Comments {
		mode = parser.ParseComments
	}

	fset := token.NewFileSet()
	p := &Parser{fset: fset}
	var err error

	switch {
	case opts.File != "":
		p.file, err = parser.ParseFile(fset, opts.File, nil, mode)
		if err != nil {
			return nil, err
		}
	case opts.Dir != "":
		p.pkgs, err = parser.ParseDir(fset, opts.Dir, nil, mode)
		if err != nil {
			return nil, err
		}
	case opts.Src != nil:
		p.file, err = parser.ParseFile(fset, "src.go", opts.Src, mode)
		if err != nil {
			return nil, err
		}
	default:
		return nil, errors.New("file, src or dir is not specified")
	}

	return p, nil
}

func checkGoFile(filePath string) bool {
	if strings.HasSuffix(filePath, ".go") {
		var (
			fset       = token.NewFileSet()
			astFile    *ast.File
			err        error
			hasGoglImp = false
		)
		if astFile, err = parser.ParseFile(fset, filePath, nil, parser.ImportsOnly); err != nil {
			panic(err)
		}
		for _, s := range astFile.Imports {
			if hasGoglImp = (strings.Index(s.Path.Value, "github.com/go3d/go-opengl/core/") >= 0); hasGoglImp {
				break
			}
		}
		if hasGoglImp {
			if astFile, err = parser.ParseFile(fset, filePath, nil, 0); err != nil {
				panic(err)
			}
			curFilePath = filePath
			ast.Inspect(astFile, inspectNode)
		}
	}
	return true
}

func applyPatches(file *ast.File, fileSet *token.FileSet, importPath string) *ast.File {
	removeImport := func(path string) {
		for _, decl := range file.Decls {
			if d, ok := decl.(*ast.GenDecl); ok && d.Tok == token.IMPORT {
				for j, spec := range d.Specs {
					value := spec.(*ast.ImportSpec).Path.Value
					if value[1:len(value)-1] == path {
						d.Specs[j] = d.Specs[len(d.Specs)-1]
						d.Specs = d.Specs[:len(d.Specs)-1]
						return
					}
				}
			}
		}
	}

	removeFunction := func(name string) {
		for i, decl := range file.Decls {
			if d, ok := decl.(*ast.FuncDecl); ok {
				if d.Name.String() == name {
					file.Decls[i] = file.Decls[len(file.Decls)-1]
					file.Decls = file.Decls[:len(file.Decls)-1]
					return
				}
			}
		}
	}

	basename := filepath.Base(fileSet.Position(file.Pos()).Filename)
	switch {
	case importPath == "bytes_test" && basename == "equal_test.go":
		file, _ = parser.ParseFile(fileSet, basename, "package bytes_test", 0)

	case importPath == "crypto/rc4" && basename == "rc4_ref.go": // see https://codereview.appspot.com/40540049/
		file, _ = parser.ParseFile(fileSet, basename, "// Copyright 2013 The Go Authors. All rights reserved.\n// Use of this source code is governed by a BSD-style\n// license that can be found in the LICENSE file.\n\n// +build !amd64,!arm,!386\n\npackage rc4\n\n// XORKeyStream sets dst to the result of XORing src with the key stream.\n// Dst and src may be the same slice but otherwise should not overlap.\nfunc (c *Cipher) XORKeyStream(dst, src []byte) {\n  i, j := c.i, c.j\n  for k, v := range src {\n    i += 1\n    j += uint8(c.s[i])\n    c.s[i], c.s[j] = c.s[j], c.s[i]\n    dst[k] = v ^ uint8(c.s[uint8(c.s[i]+c.s[j])])\n  }\n  c.i, c.j = i, j\n}", 0)

	case importPath == "encoding/json" && basename == "stream_test.go":
		removeImport("net")
		removeFunction("TestBlocking")

	case importPath == "math/big" && basename == "arith.go": // see https://codereview.appspot.com/55470046/
		file, _ = parser.ParseFile(fileSet, basename, "// Copyright 2009 The Go Authors. All rights reserved.\n// Use of this source code is governed by a BSD-style\n// license that can be found in the LICENSE file.\n\n// This file provides Go implementations of elementary multi-precision\n// arithmetic operations on word vectors. Needed for platforms without\n// assembly implementations of these routines.\n\npackage big\n\n// A Word represents a single digit of a multi-precision unsigned integer.\ntype Word uintptr\n\nconst (\n	// Compute the size _S of a Word in bytes.\n	_m    = ^Word(0)\n	_logS = _m>>8&1 + _m>>16&1 + _m>>32&1\n	_S    = 1 << _logS\n\n	_W = _S << 3 // word size in bits\n	_B = 1 << _W // digit base\n	_M = _B - 1  // digit mask\n\n	_W2 = _W / 2   // half word size in bits\n	_B2 = 1 << _W2 // half digit base\n	_M2 = _B2 - 1  // half digit mask\n)\n\n// ----------------------------------------------------------------------------\n// Elementary operations on words\n//\n// These operations are used by the vector operations below.\n\n// z1<<_W + z0 = x+y+c, with c == 0 or 1\nfunc addWW_g(x, y, c Word) (z1, z0 Word) {\n	yc := y + c\n	z0 = x + yc\n	if z0 < x || yc < y {\n		z1 = 1\n	}\n	return\n}\n\n// z1<<_W + z0 = x-y-c, with c == 0 or 1\nfunc subWW_g(x, y, c Word) (z1, z0 Word) {\n	yc := y + c\n	z0 = x - yc\n	if z0 > x || yc < y {\n		z1 = 1\n	}\n	return\n}\n\n// z1<<_W + z0 = x*y\n// Adapted from Warren, Hacker's Delight, p. 132.\nfunc mulWW_g(x, y Word) (z1, z0 Word) {\n	x0 := x & _M2\n	x1 := x >> _W2\n	y0 := y & _M2\n	y1 := y >> _W2\n	w0 := x0 * y0\n	t := x1*y0 + w0>>_W2\n	w1 := t & _M2\n	w2 := t >> _W2\n	w1 += x0 * y1\n	z1 = x1*y1 + w2 + w1>>_W2\n	z0 = x * y\n	return\n}\n\n// z1<<_W + z0 = x*y + c\nfunc mulAddWWW_g(x, y, c Word) (z1, z0 Word) {\n	z1, zz0 := mulWW(x, y)\n	if z0 = zz0 + c; z0 < zz0 {\n		z1++\n	}\n	return\n}\n\n// Length of x in bits.\nfunc bitLen_g(x Word) (n int) {\n	for ; x >= 0x8000; x >>= 16 {\n		n += 16\n	}\n	if x >= 0x80 {\n		x >>= 8\n		n += 8\n	}\n	if x >= 0x8 {\n		x >>= 4\n		n += 4\n	}\n	if x >= 0x2 {\n		x >>= 2\n		n += 2\n	}\n	if x >= 0x1 {\n		n++\n	}\n	return\n}\n\n// log2 computes the integer binary logarithm of x.\n// The result is the integer n for which 2^n <= x < 2^(n+1).\n// If x == 0, the result is -1.\nfunc log2(x Word) int {\n	return bitLen(x) - 1\n}\n\n// Number of leading zeros in x.\nfunc leadingZeros(x Word) uint {\n	return uint(_W - bitLen(x))\n}\n\n// q = (u1<<_W + u0 - r)/y\n// Adapted from Warren, Hacker's Delight, p. 152.\nfunc divWW_g(u1, u0, v Word) (q, r Word) {\n	if u1 >= v {\n		return 1<<_W - 1, 1<<_W - 1\n	}\n\n	s := leadingZeros(v)\n	v <<= s\n\n	vn1 := v >> _W2\n	vn0 := v & _M2\n	un32 := u1<<s | u0>>(_W-s)\n	un10 := u0 << s\n	un1 := un10 >> _W2\n	un0 := un10 & _M2\n	q1 := un32 / vn1\n	rhat := un32 - q1*vn1\n\n	for q1 >= _B2 || q1*vn0 > _B2*rhat+un1 {\n		q1--\n		rhat += vn1\n		if rhat >= _B2 {\n			break\n		}\n	}\n\n	un21 := un32*_B2 + un1 - q1*v\n	q0 := un21 / vn1\n	rhat = un21 - q0*vn1\n\n	for q0 >= _B2 || q0*vn0 > _B2*rhat+un0 {\n		q0--\n		rhat += vn1\n		if rhat >= _B2 {\n			break\n		}\n	}\n\n	return q1*_B2 + q0, (un21*_B2 + un0 - q0*v) >> s\n}\n\nfunc addVV_g(z, x, y []Word) (c Word) {\n	for i := range z {\n		c, z[i] = addWW_g(x[i], y[i], c)\n	}\n	return\n}\n\nfunc subVV_g(z, x, y []Word) (c Word) {\n	for i := range z {\n		c, z[i] = subWW_g(x[i], y[i], c)\n	}\n	return\n}\n\nfunc addVW_g(z, x []Word, y Word) (c Word) {\n	c = y\n	for i := range z {\n		c, z[i] = addWW_g(x[i], c, 0)\n	}\n	return\n}\n\nfunc subVW_g(z, x []Word, y Word) (c Word) {\n	c = y\n	for i := range z {\n		c, z[i] = subWW_g(x[i], c, 0)\n	}\n	return\n}\n\nfunc shlVU_g(z, x []Word, s uint) (c Word) {\n	if n := len(z); n > 0 {\n		ŝ := _W - s\n		w1 := x[n-1]\n		c = w1 >> ŝ\n		for i := n - 1; i > 0; i-- {\n			w := w1\n			w1 = x[i-1]\n			z[i] = w<<s | w1>>ŝ\n		}\n		z[0] = w1 << s\n	}\n	return\n}\n\nfunc shrVU_g(z, x []Word, s uint) (c Word) {\n	if n := len(z); n > 0 {\n		ŝ := _W - s\n		w1 := x[0]\n		c = w1 << ŝ\n		for i := 0; i < n-1; i++ {\n			w := w1\n			w1 = x[i+1]\n			z[i] = w>>s | w1<<ŝ\n		}\n		z[n-1] = w1 >> s\n	}\n	return\n}\n\nfunc mulAddVWW_g(z, x []Word, y, r Word) (c Word) {\n	c = r\n	for i := range z {\n		c, z[i] = mulAddWWW_g(x[i], y, c)\n	}\n	return\n}\n\nfunc addMulVVW_g(z, x []Word, y Word) (c Word) {\n	for i := range z {\n		z1, z0 := mulAddWWW_g(x[i], y, z[i])\n		c, z[i] = addWW_g(z0, c, 0)\n		c += z1\n	}\n	return\n}\n\nfunc divWVW_g(z []Word, xn Word, x []Word, y Word) (r Word) {\n	r = xn\n	for i := len(z) - 1; i >= 0; i-- {\n		z[i], r = divWW_g(r, x[i], y)\n	}\n	return\n}", 0)

	case importPath == "reflect_test" && basename == "all_test.go":
		removeImport("unsafe")
		removeFunction("TestAlignment")
		removeFunction("TestSliceOverflow")

	case importPath == "runtime" && strings.HasPrefix(basename, "zgoarch_"):
		file, _ = parser.ParseFile(fileSet, basename, "package runtime\nconst theGoarch = `js`\n", 0)

	case importPath == "sync/atomic_test" && basename == "atomic_test.go":
		removeFunction("TestUnaligned64")

	case importPath == "text/template/parse" && basename == "lex.go": // this patch will be removed as soon as goroutines are supported
		file, _ = parser.ParseFile(fileSet, basename, "// Copyright 2011 The Go Authors. All rights reserved.\n// Use of this source code is governed by a BSD-style\n// license that can be found in the LICENSE file.\npackage parse\nimport (\n	\"container/list\"\n	\"fmt\"\n	\"strings\"\n	\"unicode\"\n	\"unicode/utf8\"\n)\n// item represents a token or text string returned from the scanner.\ntype item struct {\n	typ itemType // The type of this item.\n	pos Pos      // The starting position, in bytes, of this item in the input string.\n	val string   // The value of this item.\n}\nfunc (i item) String() string {\n	switch {\n	case i.typ == itemEOF:\n		return \"EOF\"\n	case i.typ == itemError:\n		return i.val\n	case i.typ > itemKeyword:\n		return fmt.Sprintf(\"<%s>\", i.val)\n	case len(i.val) > 10:\n		return fmt.Sprintf(\"%.10q...\", i.val)\n	}\n	return fmt.Sprintf(\"%q\", i.val)\n}\n// itemType identifies the type of lex items.\ntype itemType int\nconst (\n	itemError        itemType = iota // error occurred; value is text of error\n	itemBool                         // boolean constant\n	itemChar                         // printable ASCII character; grab bag for comma etc.\n	itemCharConstant                 // character constant\n	itemComplex                      // complex constant (1+2i); imaginary is just a number\n	itemColonEquals                  // colon-equals (':=') introducing a declaration\n	itemEOF\n	itemField      // alphanumeric identifier starting with '.'\n	itemIdentifier // alphanumeric identifier not starting with '.'\n	itemLeftDelim  // left action delimiter\n	itemLeftParen  // '(' inside action\n	itemNumber     // simple number, including imaginary\n	itemPipe       // pipe symbol\n	itemRawString  // raw quoted string (includes quotes)\n	itemRightDelim // right action delimiter\n	itemRightParen // ')' inside action\n	itemSpace      // run of spaces separating arguments\n	itemString     // quoted string (includes quotes)\n	itemText       // plain text\n	itemVariable   // variable starting with '$', such as '$' or  '$1' or '$hello'\n	// Keywords appear after all the rest.\n	itemKeyword  // used only to delimit the keywords\n	itemDot      // the cursor, spelled '.'\n	itemDefine   // define keyword\n	itemElse     // else keyword\n	itemEnd      // end keyword\n	itemIf       // if keyword\n	itemNil      // the untyped nil constant, easiest to treat as a keyword\n	itemRange    // range keyword\n	itemTemplate // template keyword\n	itemWith     // with keyword\n)\nvar key = map[string]itemType{\n	\".\":        itemDot,\n	\"define\":   itemDefine,\n	\"else\":     itemElse,\n	\"end\":      itemEnd,\n	\"if\":       itemIf,\n	\"range\":    itemRange,\n	\"nil\":      itemNil,\n	\"template\": itemTemplate,\n	\"with\":     itemWith,\n}\nconst eof = -1\n// stateFn represents the state of the scanner as a function that returns the next state.\ntype stateFn func(*lexer) stateFn\n// lexer holds the state of the scanner.\ntype lexer struct {\n	name       string     // the name of the input; used only for error reports\n	input      string     // the string being scanned\n	leftDelim  string     // start of action\n	rightDelim string     // end of action\n	state      stateFn    // the next lexing function to enter\n	pos        Pos        // current position in the input\n	start      Pos        // start position of this item\n	width      Pos        // width of last rune read from input\n	lastPos    Pos        // position of most recent item returned by nextItem\n	items      *list.List // scanned items\n	parenDepth int        // nesting depth of ( ) exprs\n}\n// next returns the next rune in the input.\nfunc (l *lexer) next() rune {\n	if int(l.pos) >= len(l.input) {\n		l.width = 0\n		return eof\n	}\n	r, w := utf8.DecodeRuneInString(l.input[l.pos:])\n	l.width = Pos(w)\n	l.pos += l.width\n	return r\n}\n// peek returns but does not consume the next rune in the input.\nfunc (l *lexer) peek() rune {\n	r := l.next()\n	l.backup()\n	return r\n}\n// backup steps back one rune. Can only be called once per call of next.\nfunc (l *lexer) backup() {\n	l.pos -= l.width\n}\n// emit passes an item back to the client.\nfunc (l *lexer) emit(t itemType) {\n	l.items.PushBack(item{t, l.start, l.input[l.start:l.pos]})\n	l.start = l.pos\n}\n// ignore skips over the pending input before this point.\nfunc (l *lexer) ignore() {\n	l.start = l.pos\n}\n// accept consumes the next rune if it's from the valid set.\nfunc (l *lexer) accept(valid string) bool {\n	if strings.IndexRune(valid, l.next()) >= 0 {\n		return true\n	}\n	l.backup()\n	return false\n}\n// acceptRun consumes a run of runes from the valid set.\nfunc (l *lexer) acceptRun(valid string) {\n	for strings.IndexRune(valid, l.next()) >= 0 {\n	}\n	l.backup()\n}\n// lineNumber reports which line we're on, based on the position of\n// the previous item returned by nextItem. Doing it this way\n// means we don't have to worry about peek double counting.\nfunc (l *lexer) lineNumber() int {\n	return 1 + strings.Count(l.input[:l.lastPos], \"\\n\")\n}\n// errorf returns an error token and terminates the scan by passing\n// back a nil pointer that will be the next state, terminating l.nextItem.\nfunc (l *lexer) errorf(format string, args ...interface{}) stateFn {\n	l.items.PushBack(item{itemError, l.start, fmt.Sprintf(format, args...)})\n	return nil\n}\n// nextItem returns the next item from the input.\nfunc (l *lexer) nextItem() item {\n	element := l.items.Front()\n	for element == nil {\n		l.state = l.state(l)\n		element = l.items.Front()\n	}\n	l.items.Remove(element)\n	item := element.Value.(item)\n	l.lastPos = item.pos\n	return item\n}\n// lex creates a new scanner for the input string.\nfunc lex(name, input, left, right string) *lexer {\n	if left == \"\" {\n		left = leftDelim\n	}\n	if right == \"\" {\n		right = rightDelim\n	}\n	l := &lexer{\n		name:       name,\n		input:      input,\n		leftDelim:  left,\n		rightDelim: right,\n		items:      list.New(),\n	}\n	l.state = lexText\n	return l\n}\n// state functions\nconst (\n	leftDelim    = \"{{\"\n	rightDelim   = \"}}\"\n	leftComment  = \"/*\"\n	rightComment = \"*/\"\n)\n// lexText scans until an opening action delimiter, \"{{\".\nfunc lexText(l *lexer) stateFn {\n	for {\n		if strings.HasPrefix(l.input[l.pos:], l.leftDelim) {\n			if l.pos > l.start {\n				l.emit(itemText)\n			}\n			return lexLeftDelim\n		}\n		if l.next() == eof {\n			break\n		}\n	}\n	// Correctly reached EOF.\n	if l.pos > l.start {\n		l.emit(itemText)\n	}\n	l.emit(itemEOF)\n	return nil\n}\n// lexLeftDelim scans the left delimiter, which is known to be present.\nfunc lexLeftDelim(l *lexer) stateFn {\n	l.pos += Pos(len(l.leftDelim))\n	if strings.HasPrefix(l.input[l.pos:], leftComment) {\n		return lexComment\n	}\n	l.emit(itemLeftDelim)\n	l.parenDepth = 0\n	return lexInsideAction\n}\n// lexComment scans a comment. The left comment marker is known to be present.\nfunc lexComment(l *lexer) stateFn {\n	l.pos += Pos(len(leftComment))\n	i := strings.Index(l.input[l.pos:], rightComment)\n	if i < 0 {\n		return l.errorf(\"unclosed comment\")\n	}\n	l.pos += Pos(i + len(rightComment))\n	if !strings.HasPrefix(l.input[l.pos:], l.rightDelim) {\n		return l.errorf(\"comment ends before closing delimiter\")\n	}\n	l.pos += Pos(len(l.rightDelim))\n	l.ignore()\n	return lexText\n}\n// lexRightDelim scans the right delimiter, which is known to be present.\nfunc lexRightDelim(l *lexer) stateFn {\n	l.pos += Pos(len(l.rightDelim))\n	l.emit(itemRightDelim)\n	return lexText\n}\n// lexInsideAction scans the elements inside action delimiters.\nfunc lexInsideAction(l *lexer) stateFn {\n	// Either number, quoted string, or identifier.\n	// Spaces separate arguments; runs of spaces turn into itemSpace.\n	// Pipe symbols separate and are emitted.\n	if strings.HasPrefix(l.input[l.pos:], l.rightDelim) {\n		if l.parenDepth == 0 {\n			return lexRightDelim\n		}\n		return l.errorf(\"unclosed left paren\")\n	}\n	switch r := l.next(); {\n	case r == eof || isEndOfLine(r):\n		return l.errorf(\"unclosed action\")\n	case isSpace(r):\n		return lexSpace\n	case r == ':':\n		if l.next() != '=' {\n			return l.errorf(\"expected :=\")\n		}\n		l.emit(itemColonEquals)\n	case r == '|':\n		l.emit(itemPipe)\n	case r == '\"':\n		return lexQuote\n	case r == '`':\n		return lexRawQuote\n	case r == '$':\n		return lexVariable\n	case r == '\\'':\n		return lexChar\n	case r == '.':\n		// special look-ahead for \".field\" so we don't break l.backup().\n		if l.pos < Pos(len(l.input)) {\n			r := l.input[l.pos]\n			if r < '0' || '9' < r {\n				return lexField\n			}\n		}\n		fallthrough // '.' can start a number.\n	case r == '+' || r == '-' || ('0' <= r && r <= '9'):\n		l.backup()\n		return lexNumber\n	case isAlphaNumeric(r):\n		l.backup()\n		return lexIdentifier\n	case r == '(':\n		l.emit(itemLeftParen)\n		l.parenDepth++\n		return lexInsideAction\n	case r == ')':\n		l.emit(itemRightParen)\n		l.parenDepth--\n		if l.parenDepth < 0 {\n			return l.errorf(\"unexpected right paren %#U\", r)\n		}\n		return lexInsideAction\n	case r <= unicode.MaxASCII && unicode.IsPrint(r):\n		l.emit(itemChar)\n		return lexInsideAction\n	default:\n		return l.errorf(\"unrecognized character in action: %#U\", r)\n	}\n	return lexInsideAction\n}\n// lexSpace scans a run of space characters.\n// One space has already been seen.\nfunc lexSpace(l *lexer) stateFn {\n	for isSpace(l.peek()) {\n		l.next()\n	}\n	l.emit(itemSpace)\n	return lexInsideAction\n}\n// lexIdentifier scans an alphanumeric.\nfunc lexIdentifier(l *lexer) stateFn {\nLoop:\n	for {\n		switch r := l.next(); {\n		case isAlphaNumeric(r):\n			// absorb.\n		default:\n			l.backup()\n			word := l.input[l.start:l.pos]\n			if !l.atTerminator() {\n				return l.errorf(\"bad character %#U\", r)\n			}\n			switch {\n			case key[word] > itemKeyword:\n				l.emit(key[word])\n			case word[0] == '.':\n				l.emit(itemField)\n			case word == \"true\", word == \"false\":\n				l.emit(itemBool)\n			default:\n				l.emit(itemIdentifier)\n			}\n			break Loop\n		}\n	}\n	return lexInsideAction\n}\n// lexField scans a field: .Alphanumeric.\n// The . has been scanned.\nfunc lexField(l *lexer) stateFn {\n	return lexFieldOrVariable(l, itemField)\n}\n// lexVariable scans a Variable: $Alphanumeric.\n// The $ has been scanned.\nfunc lexVariable(l *lexer) stateFn {\n	if l.atTerminator() { // Nothing interesting follows -> \"$\".\n		l.emit(itemVariable)\n		return lexInsideAction\n	}\n	return lexFieldOrVariable(l, itemVariable)\n}\n// lexVariable scans a field or variable: [.$]Alphanumeric.\n// The . or $ has been scanned.\nfunc lexFieldOrVariable(l *lexer, typ itemType) stateFn {\n	if l.atTerminator() { // Nothing interesting follows -> \".\" or \"$\".\n		if typ == itemVariable {\n			l.emit(itemVariable)\n		} else {\n			l.emit(itemDot)\n		}\n		return lexInsideAction\n	}\n	var r rune\n	for {\n		r = l.next()\n		if !isAlphaNumeric(r) {\n			l.backup()\n			break\n		}\n	}\n	if !l.atTerminator() {\n		return l.errorf(\"bad character %#U\", r)\n	}\n	l.emit(typ)\n	return lexInsideAction\n}\n// atTerminator reports whether the input is at valid termination character to\n// appear after an identifier. Breaks .X.Y into two pieces. Also catches cases\n// like \"$x+2\" not being acceptable without a space, in case we decide one\n// day to implement arithmetic.\nfunc (l *lexer) atTerminator() bool {\n	r := l.peek()\n	if isSpace(r) || isEndOfLine(r) {\n		return true\n	}\n	switch r {\n	case eof, '.', ',', '|', ':', ')', '(':\n		return true\n	}\n	// Does r start the delimiter? This can be ambiguous (with delim==\"//\", $x/2 will\n	// succeed but should fail) but only in extremely rare cases caused by willfully\n	// bad choice of delimiter.\n	if rd, _ := utf8.DecodeRuneInString(l.rightDelim); rd == r {\n		return true\n	}\n	return false\n}\n// lexChar scans a character constant. The initial quote is already\n// scanned. Syntax checking is done by the parser.\nfunc lexChar(l *lexer) stateFn {\nLoop:\n	for {\n		switch l.next() {\n		case '\\\\':\n			if r := l.next(); r != eof && r != '\\n' {\n				break\n			}\n			fallthrough\n		case eof, '\\n':\n			return l.errorf(\"unterminated character constant\")\n		case '\\'':\n			break Loop\n		}\n	}\n	l.emit(itemCharConstant)\n	return lexInsideAction\n}\n// lexNumber scans a number: decimal, octal, hex, float, or imaginary. This\n// isn't a perfect number scanner - for instance it accepts \".\" and \"0x0.2\"\n// and \"089\" - but when it's wrong the input is invalid and the parser (via\n// strconv) will notice.\nfunc lexNumber(l *lexer) stateFn {\n	if !l.scanNumber() {\n		return l.errorf(\"bad number syntax: %q\", l.input[l.start:l.pos])\n	}\n	if sign := l.peek(); sign == '+' || sign == '-' {\n		// Complex: 1+2i. No spaces, must end in 'i'.\n		if !l.scanNumber() || l.input[l.pos-1] != 'i' {\n			return l.errorf(\"bad number syntax: %q\", l.input[l.start:l.pos])\n		}\n		l.emit(itemComplex)\n	} else {\n		l.emit(itemNumber)\n	}\n	return lexInsideAction\n}\nfunc (l *lexer) scanNumber() bool {\n	// Optional leading sign.\n	l.accept(\"+-\")\n	// Is it hex?\n	digits := \"0123456789\"\n	if l.accept(\"0\") && l.accept(\"xX\") {\n		digits = \"0123456789abcdefABCDEF\"\n	}\n	l.acceptRun(digits)\n	if l.accept(\".\") {\n		l.acceptRun(digits)\n	}\n	if l.accept(\"eE\") {\n		l.accept(\"+-\")\n		l.acceptRun(\"0123456789\")\n	}\n	// Is it imaginary?\n	l.accept(\"i\")\n	// Next thing mustn't be alphanumeric.\n	if isAlphaNumeric(l.peek()) {\n		l.next()\n		return false\n	}\n	return true\n}\n// lexQuote scans a quoted string.\nfunc lexQuote(l *lexer) stateFn {\nLoop:\n	for {\n		switch l.next() {\n		case '\\\\':\n			if r := l.next(); r != eof && r != '\\n' {\n				break\n			}\n			fallthrough\n		case eof, '\\n':\n			return l.errorf(\"unterminated quoted string\")\n		case '\"':\n			break Loop\n		}\n	}\n	l.emit(itemString)\n	return lexInsideAction\n}\n// lexRawQuote scans a raw quoted string.\nfunc lexRawQuote(l *lexer) stateFn {\nLoop:\n	for {\n		switch l.next() {\n		case eof, '\\n':\n			return l.errorf(\"unterminated raw quoted string\")\n		case '`':\n			break Loop\n		}\n	}\n	l.emit(itemRawString)\n	return lexInsideAction\n}\n// isSpace reports whether r is a space character.\nfunc isSpace(r rune) bool {\n	return r == ' ' || r == '\\t'\n}\n// isEndOfLine reports whether r is an end-of-line character.\nfunc isEndOfLine(r rune) bool {\n	return r == '\\r' || r == '\\n'\n}\n// isAlphaNumeric reports whether r is an alphabetic, digit, or underscore.\nfunc isAlphaNumeric(r rune) bool {\n	return r == '_' || unicode.IsLetter(r) || unicode.IsDigit(r)\n}", 0)
	}

	return file
}

func parse(fset *token.FileSet, src []byte) (interface{}, error) {
	// Try as a complete source file.
	file, err := parser.ParseFile(fset, "", src, parser.ParseComments)
	if err == nil {
		return file, nil
	}
	// If the source is missing a package clause, try as a source fragment; otherwise fail.
	if !strings.Contains(err.Error(), "expected 'package'") {
		return nil, err
	}

	// Try as a declaration list by prepending a package clause in front of src.
	// Use ';' not '\n' to keep line numbers intact.
	psrc := append([]byte("package p;"), src...)
	file, err = parser.ParseFile(fset, "", psrc, parser.ParseComments)
	if err == nil {
		return file.Decls, nil
	}
	// If the source is missing a declaration, try as a statement list; otherwise fail.
	if !strings.Contains(err.Error(), "expected declaration") {
		return nil, err
	}

	// Try as statement list by wrapping a function around src.
	fsrc := append(append([]byte("package p; func _() {"), src...), '}')
	file, err = parser.ParseFile(fset, "", fsrc, parser.ParseComments)
	if err == nil {
		return file.Decls[0].(*ast.FuncDecl).Body.List, nil
	}

	// Failed, and out of options.
	return nil, err
}

func GetCurrentAppSettings(settings_path string)(settings map[string]string,err error){

    fset := token.NewFileSet()

    f, err := parser.ParseFile(fset, default_settings_path, nil, 0)
    if err != nil {
        f, err = parser.ParseFile(fset, default_relative_settings_path, nil, 0)
        if err!=nil{
            return nil,err
        }
    }

    conf := types.Config{Importer: importer.Default()}
    pkg, err := conf.Check("wapour/settings", fset, []*ast.File{f}, nil)
    if err != nil {
        return nil,err
    }
    settings=make(map[string]string,0)
    for word_id := range initial {
        word:=initial[word_id]
        existing_set:=pkg.Scope().Lookup(word).(*types.Const).Val().String()
        settings[word]=existing_set
    }
    return settings,err
}

func GetPackageList() {
	for _, fname := range files {
		file, err := parser.ParseFile(fname, nil, parser.PackageClauseOnly)
		if err != nil {
			fmt.Fprint(os.Stderr, err)
			os.Exit(1)
		}
		pname := file.Name.Name
		if pname == "main" {
			fullfile, err := parser.ParseFile(fname, nil, 0)
			if err == nil {
				v := &MainCheckVisitor{fname: fname}
				ast.Walk(v, fullfile)
				if v.hasMain {
					// get the name from the filename
					fparts := strings.Split(fname, ".", -1)
					basename := path.Base(fparts[0])
					packages[basename] = nil
				} else {
					packages[pname] = nil
				}
			}
		} else {
			packages[file.Name.Name] = nil
		}
	}
}

func Print(filename string, source interface{}) (pretty string, ok os.Error) {
	fileAst, ok := parser.ParseFile(filename, source, 4)

	// Make common corrections for snippet pastes
	if ok != nil && source != nil {
		src := source.(string)

		if m, _ := regexp.MatchString(`^package`, src); !m {
			src = "package main\n\n" + src
		}

		if fileAst, ok = parser.ParseFile(filename, src, 4); ok != nil {
			return
		}
	}

	coll := new(collector)
	coll.contents = new(vector.StringVector)

	(&printer.Config{
		Mode:     5,
		Tabwidth: 4,
		Styler:   new(HTMLStyler),
	}).Fprint(coll, fileAst)

	pretty = strings.Join(coll.contents.Data(), "")

	return
}

// inspired by godeps rewrite, rewrites import paths with gx vendored names
func rewriteImportsInFile(fi string, rw func(string) string) error {
	cfg := &printer.Config{Mode: printer.UseSpaces | printer.TabIndent, Tabwidth: 8}
	fset := token.NewFileSet()
	file, err := parser.ParseFile(fset, fi, nil, parser.ParseComments)
	if err != nil {
		return err
	}

	var changed bool
	for _, imp := range file.Imports {
		p, err := strconv.Unquote(imp.Path.Value)
		if err != nil {
			return err
		}

		np := rw(p)

		if np != p {
			changed = true
			imp.Path.Value = strconv.Quote(np)
		}
	}

	if !changed {
		return nil
	}

	buf := bufpool.Get().(*bytes.Buffer)
	if err = cfg.Fprint(buf, fset, file); err != nil {
		return err
	}

	fset = token.NewFileSet()
	file, err = parser.ParseFile(fset, fi, buf, parser.ParseComments)
	if err != nil {
		return err
	}

	buf.Reset()
	bufpool.Put(buf)

	ast.SortImports(fset, file)

	wpath := fi + ".temp"
	w, err := os.Create(wpath)
	if err != nil {
		return err
	}

	if err = cfg.Fprint(w, fset, file); err != nil {
		return err
	}

	if err = w.Close(); err != nil {
		return err
	}

	return os.Rename(wpath, fi)
}

// parse parses src, which was read from filename,
// as a Go source file or statement list.
func parse(fset *token.FileSet, filename string, src []byte, stdin bool) (*ast.File, func(orig, src []byte) []byte, error) {
	// Try as whole source file.
	file, err := parser.ParseFile(fset, filename, src, parserMode)
	if err == nil {
		return file, nil, nil
	}
	// If the error is that the source file didn't begin with a
	// package line and this is standard input, fall through to
	// try as a source fragment.  Stop and return on any other error.
	if !stdin || !strings.Contains(err.Error(), "expected 'package'") {
		return nil, nil, err
	}

	// If this is a declaration list, make it a source file
	// by inserting a package clause.
	// Insert using a ;, not a newline, so that the line numbers
	// in psrc match the ones in src.
	psrc := append([]byte("package p;"), src...)
	file, err = parser.ParseFile(fset, filename, psrc, parserMode)
	if err == nil {
		adjust := func(orig, src []byte) []byte {
			// Remove the package clause.
			// Gofmt has turned the ; into a \n.
			src = src[len("package p\n"):]
			return matchSpace(orig, src)
		}
		return file, adjust, nil
	}
	// If the error is that the source file didn't begin with a
	// declaration, fall through to try as a statement list.
	// Stop and return on any other error.
	if !strings.Contains(err.Error(), "expected declaration") {
		return nil, nil, err
	}

	// If this is a statement list, make it a source file
	// by inserting a package clause and turning the list
	// into a function body.  This handles expressions too.
	// Insert using a ;, not a newline, so that the line numbers
	// in fsrc match the ones in src.
	fsrc := append(append([]byte("package p; func _() {"), src...), '}')
	file, err = parser.ParseFile(fset, filename, fsrc, parserMode)
	if err == nil {
		adjust := func(orig, src []byte) []byte {
			// Remove the wrapping.
			// Gofmt has turned the ; into a \n\n.
			src = src[len("package p\n\nfunc _() {"):]
			src = src[:len(src)-len("}\n")]
			// Gofmt has also indented the function body one level.
			// Remove that indent.
			src = bytes.Replace(src, []byte("\n\t"), []byte("\n"), -1)
			return matchSpace(orig, src)
		}
		return file, adjust, nil
	}

	// Failed, and out of options.
	return nil, nil, err
}

func getImports(dir string) *DepSet {
	var pf *ast.File
	var err error
	fset = token.NewFileSet()
	files := getGoFiles(dir)
	dset := NewDepSet()

	for _, file := range files {
		if showCalls == true {
			pf, err = parser.ParseFile(fset, file, nil, 0)
			// Build a map with the imports mapping to the files
			for _, s := range pf.Imports {
				pname := strings.Trim(s.Path.Value, "\"")
				if debug {
					fmt.Printf("Import found: %s imports %s\n", file, pname)
				}
				dset.AddImport(pname, file)
			}

			if debug {
				for _, pkg := range dset.Packages() {
					fmt.Printf("Imported: %s\n", pkg)
				}
			}

			// ast.Inspect(pf, parseCalls)
			ast.Walk(finder{
				find: findCalls,
				dset: dset,
			}, pf)
		} else {
			pf, err = parser.ParseFile(fset, file, nil, parser.ImportsOnly)
			// Build a map with the imports mapping to the files
			for _, s := range pf.Imports {
				pname := strings.Trim(s.Path.Value, "\"")
				dset.AddImport(pname, file)
			}
		}
		if err != nil {
			// fmt.Println(err)
		}

		/*
		 * We'll need to AND the imports and the keys in the
		 * package calls map to trim out keys from the latter
		 * which are not actually packages.
		 * We also need to figure out how to account for methods -
		 * since the qualifier (X node) in those cases is the
		 * method receiver, not the package.
		 */
	}

	return dset
}

func (b *builder) merge() ([]byte, error) {
	var buf bytes.Buffer
	if err := b.tpl.Execute(&buf, b); err != nil {
		return nil, err
	}

	f, err := parser.ParseFile(b.fset, "", &buf, 0)
	if err != nil {
		return nil, err
	}
	// b.imports(f)
	b.deleteImports(f)
	b.files["main.go"] = f

	pkg, _ := ast.NewPackage(b.fset, b.files, nil, nil)
	pkg.Name = "main"

	ret, err := ast.MergePackageFiles(pkg, 0), nil
	if err != nil {
		return nil, err
	}

	// @TODO: we reread the file, probably something goes wrong with position
	buf.Reset()
	if err = format.Node(&buf, b.fset, ret); err != nil {
		return nil, err
	}

	ret, err = parser.ParseFile(b.fset, "", buf.Bytes(), 0)
	if err != nil {
		return nil, err
	}

	for _, spec := range b.imports {
		var name string
		if spec.Name != nil {
			name = spec.Name.Name
		}
		ipath, _ := strconv.Unquote(spec.Path.Value)
		addImport(b.fset, ret, name, ipath)
	}

	buf.Reset()
	if err := format.Node(&buf, b.fset, ret); err != nil {
		return nil, err
	}

	return buf.Bytes(), nil
}

func main() {
	fileSet := token.NewFileSet()
	comFileSet := token.NewFileSet() // The FileSet used to parse the COM declarations.
	mod := newModule(comFileSet)

	// Iterate over all the files specified on the command line.
	for _, filename := range os.Args[1:] {
		f, err := parser.ParseFile(fileSet, filename, nil, parser.ParseComments)
		if err != nil {
			log.Fatalln("error parsing the source file", filename, ":", err)
		}

		// Iterate over all the comments in the current file, picking out the ones that
		// start with "com".
		// Join them into a long string to be parsed, starting with a package declaration.
		chunks := []string{"package " + f.Name.Name}
		for _, cg := range f.Comments {
			for _, c := range cg.List {
				text := strings.TrimSpace(strings.Trim(c.Text, "/*"))
				if strings.HasPrefix(text, "com") {
					text = text[len("com"):]
					if text == "" || !strings.Contains(" \t\n", text[:1]) {
						continue
					}
					text = strings.TrimSpace(text)
					chunks = append(chunks, text)
				}
			}
		}
		comDecls := strings.Join(chunks, "\n")

		// Now parse the concatenated result as a Go source file.
		comAST, err := parser.ParseFile(comFileSet, filename, comDecls, parser.ParseComments)
		if err != nil {
			log.Fatalln("error parsing the COM declarations from", filename, ":", err)
		}

		err = mod.loadFile(comAST)
		if err != nil {
			log.Fatalln("error loading declarations from", filename, "into module:", err)
		}
	}

	err := mod.write(os.Stdout)
	if err != nil {
		log.Fatalln("error generating output:", err)
	}
}

// rewriteGoFile rewrites import statments in the named file
// according to the rules for func qualify.
func rewriteGoFile(name, qual string, paths []string) error {
	debugln("rewriteGoFile", name, ",", qual, ",", paths)
	printerConfig := &printer.Config{Mode: printer.TabIndent | printer.UseSpaces, Tabwidth: 8}
	fset := token.NewFileSet()
	f, err := parser.ParseFile(fset, name, nil, parser.ParseComments)
	if err != nil {
		return err
	}

	var changed bool
	for _, s := range f.Imports {
		name, err := strconv.Unquote(s.Path.Value)
		if err != nil {
			return err // can't happen
		}
		q := qualify(unqualify(name), qual, paths)
		if q != name {
			s.Path.Value = strconv.Quote(q)
			changed = true
		}
	}
	if !changed {
		return nil
	}
	var buffer bytes.Buffer
	if err = printerConfig.Fprint(&buffer, fset, f); err != nil {
		return err
	}
	fset = token.NewFileSet()
	f, err = parser.ParseFile(fset, name, &buffer, parser.ParseComments)
	ast.SortImports(fset, f)
	tpath := name + ".temp"
	t, err := os.Create(tpath)
	if err != nil {
		return err
	}
	if err = printerConfig.Fprint(t, fset, f); err != nil {
		return err
	}
	if err = t.Close(); err != nil {
		return err
	}
	// This is required before the rename on windows.
	if err = os.Remove(name); err != nil {
		return err
	}
	return os.Rename(tpath, name)
}

func pkgForPath(path string) (*types.Package, error) {
	// collect filenames
	ctxt := build.Default
	pkginfo, err := ctxt.Import(path, "", 0)
	if err != nil {
		return nil, err
	}
	filenames := append(pkginfo.GoFiles, pkginfo.CgoFiles...)

	// parse files
	fset := token.NewFileSet()
	files := make([]*ast.File, len(filenames))
	for i, filename := range filenames {
		var err error
		files[i], err = parser.ParseFile(fset, filepath.Join(pkginfo.Dir, filename), nil, 0)
		if err != nil {
			return nil, err
		}
	}

	// typecheck files
	// (we only care about exports and thus can ignore function bodies)
	conf := types.Config{IgnoreFuncBodies: true, FakeImportC: true}
	return conf.Check(path, fset, files, nil)
}