#include "Python.h"

#include "Python-ast.h"

#include "node.h"

#include "token.h"

#include "graminit.h"

#include "code.h"

#include "compile.h"

#include "symtable.h"

#define UNDEFINED_FUTURE_FEATURE "future feature %.100s is not defined"

static int

future_check_features(PyFutureFeatures *ff, stmt_ty s, const char *filename)

{

	int i;

	asdl_seq *names;

	assert(s->kind == ImportFrom_kind);

	names = s->v.ImportFrom.names;

	for (i = 0; i < asdl_seq_LEN(names); i++) {

                alias_ty name = (alias_ty)asdl_seq_GET(names, i);

		const char *feature = PyString_AsString(name->name);

		if (!feature)

			return 0;

		if (strcmp(feature, FUTURE_NESTED_SCOPES) == 0) {

			continue;

		} else if (strcmp(feature, FUTURE_GENERATORS) == 0) {

			continue;

		} else if (strcmp(feature, FUTURE_DIVISION) == 0) {

			ff->ff_features |= CO_FUTURE_DIVISION;

		} else if (strcmp(feature, FUTURE_ABSOLUTE_IMPORT) == 0) {

			ff->ff_features |= CO_FUTURE_ABSOLUTE_IMPORT;

		} else if (strcmp(feature, FUTURE_WITH_STATEMENT) == 0) {

			ff->ff_features |= CO_FUTURE_WITH_STATEMENT;

		} else if (strcmp(feature, FUTURE_PRINT_FUNCTION) == 0) {

			ff->ff_features |= CO_FUTURE_PRINT_FUNCTION;

		} else if (strcmp(feature, FUTURE_UNICODE_LITERALS) == 0) {

			ff->ff_features |= CO_FUTURE_UNICODE_LITERALS;

		} else if (strcmp(feature, "braces") == 0) {

			PyErr_SetString(PyExc_SyntaxError,

					"not a chance");

			PyErr_SyntaxLocation(filename, s->lineno);

			return 0;

		} else {

			PyErr_Format(PyExc_SyntaxError,

				     UNDEFINED_FUTURE_FEATURE, feature);

			PyErr_SyntaxLocation(filename, s->lineno);

			return 0;

		}

	}

	return 1;

}

static int

future_parse(PyFutureFeatures *ff, mod_ty mod, const char *filename)

{

	int i, found_docstring = 0, done = 0, prev_line = 0;

	static PyObject *future;

	if (!future) {

		future = PyString_InternFromString("__future__");

		if (!future)

			return 0;

	}

	if (!(mod->kind == Module_kind || mod->kind == Interactive_kind))

		return 1;

	/* A subsequent pass will detect future imports that don't

	   appear at the beginning of the file.  There's one case,

	   however, that is easier to handle here: A series of imports

	   joined by semi-colons, where the first import is a future

	   statement but some subsequent import has the future form

	   but is preceded by a regular import.

	*/

	for (i = 0; i < asdl_seq_LEN(mod->v.Module.body); i++) {

		stmt_ty s = (stmt_ty)asdl_seq_GET(mod->v.Module.body, i);

		if (done && s->lineno > prev_line)

			return 1;

		prev_line = s->lineno;

		/* The tests below will return from this function unless it is

		   still possible to find a future statement.  The only things

		   that can precede a future statement are another future

		   statement and a doc string.

		*/

		if (s->kind == ImportFrom_kind) {

			if (s->v.ImportFrom.module == future) {

				if (done) {

					PyErr_SetString(PyExc_SyntaxError,

							ERR_LATE_FUTURE);

					PyErr_SyntaxLocation(filename, 

							     s->lineno);

					return 0;

				}

				if (!future_check_features(ff, s, filename))

					return 0;

				ff->ff_lineno = s->lineno;

			}

			else

				done = 1;

		}

		else if (s->kind == Expr_kind && !found_docstring) {

			expr_ty e = s->v.Expr.value;

			if (e->kind != Str_kind)

				done = 1;

			else

				found_docstring = 1;

		}

		else

			done = 1;

	}

	return 1;

}

PyFutureFeatures *

PyFuture_FromAST(mod_ty mod, const char *filename)

{

	PyFutureFeatures *ff;

	ff = (PyFutureFeatures *)PyObject_Malloc(sizeof(PyFutureFeatures));

	if (ff == NULL) {

		PyErr_NoMemory();

		return NULL;

	}

	ff->ff_features = 0;

	ff->ff_lineno = -1;

	if (!future_parse(ff, mod, filename)) {

		PyObject_Free(ff);

		return NULL;

	}

	return ff;

}