#! /usr/bin/env python
# -*- Mode: python; tab-width: 4; indent-tabs-mode: t -*-
#
# This file is part of the LibreOffice project.
#
# This Source Code Form is subject to the terms of the Mozilla Public
# License, v. 2.0. If a copy of the MPL was not distributed with this
# file, You can obtain one at http://mozilla.org/MPL/2.0/.
#

"""
This script is to fix precompiled headers.

This script runs in two modes.
In one mode, it starts with a header
that doesn't compile. If finds the
minimum number of includes in the
header to remove to get a successful
run of the command (i.e. compile).

In the second mode, it starts with a
header that compiles fine, however,
it contains one or more required
include without which it wouldn't
compile, which it identifies.
This mode is used to find source
files that miss one or more includes
and rely on pch file to compile.

Usage: ./bin/update_pch_bisect ./vcl/inc/pch/precompiled_vcl.hxx "/opt/lo/bin/make vcl.build" --find-required --verbose
"""

from __future__ import print_function

import sys
import re
import os
import unittest
import subprocess

SILENT = True
FIND_CONFLICTS = True

IGNORE = 0
GOOD = 1
TEST_ON = 2
TEST_OFF = 3
BAD = 4

def run(command):
    try:
        cmd = command.split(' ', 1)
        status = subprocess.call(cmd, stdout=open(os.devnull, 'w'),
                                 stderr=subprocess.STDOUT, close_fds=True)
        return True if status == 0 else False
    except Exception as e:
        sys.stderr.write('Error: {}\n'.format(e))
        return False

def update_pch(filename, lines, marks):
    with open(filename, 'w') as f:
        for i in xrange(len(marks)):
            mark = marks[i]
            if mark <= TEST_ON:
                f.write(lines[i])
            else:
                f.write('//' + lines[i])

def log(*args, **kwargs):
    global SILENT
    if not SILENT:
        print(*args, **kwargs)

def bisect(lines, marks, min, max, update, command):
    """ Disable half the includes and
        calls the command.
        Depending on the result,
        recurse or return.
    """
    global FIND_CONFLICTS

    log('Bisecting [{}, {}].'.format(min+1, max))
    for i in range(min, max):
        if marks[i] != IGNORE:
            marks[i] = TEST_ON if FIND_CONFLICTS else TEST_OFF

    assume_fail = False
    if not FIND_CONFLICTS:
        on_list = [x for x in marks if x in (TEST_ON, GOOD)]
        assume_fail = (len(on_list) == 0)

    update(lines, marks)
    if assume_fail or not command():
        # Failed
        log('Failed [{}, {}].'.format(min+1, max))
        if min >= max - 1:
            if not FIND_CONFLICTS:
                # Try with this one alone.
                marks[min] = TEST_ON
                update(lines, marks)
                if command():
                    log(' Found #{}: {}'.format(min+1, lines[min].strip('\n')))
                    marks[min] = GOOD
                    return marks
            else:
                log(' Found #{}: {}'.format(min+1, lines[min].strip('\n')))
            # Either way, this one is irrelevant.
            marks[min] = BAD
            return marks

        # Bisect
        for i in range(min, max):
            if marks[i] != IGNORE:
                marks[i] = TEST_OFF if FIND_CONFLICTS else TEST_ON

        half = min + ((max - min) / 2)
        marks = bisect(lines, marks, min, half, update, command)
        marks = bisect(lines, marks, half, max, update, command)
    else:
        # Success
        if FIND_CONFLICTS:
            log(' Good [{}, {}].'.format(min+1, max))
            for i in range(min, max):
                if marks[i] != IGNORE:
                    marks[i] = GOOD

    return marks

def get_filename(line):
    """ Strips the line from the
        '#include' and angled brakets
        and return the filename only.
    """
    return re.sub(r'(.*#include\s*)<(.*)>(.*)', r'\2', line)

def get_marks(lines):
    marks = []
    min = -1
    max = -1
    for i in xrange(len(lines)):
        line = lines[i]
        if line.startswith('#include'):
            marks.append(TEST_ON)
            min = i if min < 0 else min
            max = i
        else:
            marks.append(IGNORE)

    return (marks, min, max+1)

def main():

    global FIND_CONFLICTS
    global SILENT

    filename = sys.argv[1]
    command = sys.argv[2]

    for i in range(3, len(sys.argv)):
        opt = sys.argv[i]
        if opt == '--find-conflicts':
            FIND_CONFLICTS = True
        elif opt == '--find-required':
            FIND_CONFLICTS = False
        elif opt == '--verbose':
            SILENT = False
        else:
            sys.stderr.write('Error: Unknown option [{}].\n'.format(opt))
            return 1

    lines = []
    with open(filename) as f:
        lines = f.readlines()

    (marks, min, max) = get_marks(lines)

    # Test preconditions.
    log('Validating all-excluded state...')
    for i in range(min, max):
        if marks[i] != IGNORE:
            marks[i] = TEST_OFF
    update_pch(filename, lines, marks)
    res = run(command)

    if FIND_CONFLICTS:
        # Must build all excluded.
        if not res:
            sys.stderr.write("Error: broken state when all excluded, fix first and try again.")
            return 1
    else:
        # If builds all excluded, we can't bisect.
        if res:
            sys.stderr.write("Done: in good state when all excluded, nothing to do.")
            return 1

        # Must build all included.
        log('Validating all-included state...')
        for i in range(min, max):
            if marks[i] != IGNORE:
                marks[i] = TEST_ON
        update_pch(filename, lines, marks)
        if not run(command):
            sys.stderr.write("Error: broken state without modifying, fix first and try again.")
            return 1

    marks = bisect(lines, marks, min, max+1,
                   lambda l, m: update_pch(filename, l, m),
                   lambda: run(command))
    if not FIND_CONFLICTS:
        # Simplify further, as sometimes we can have
        # false positives due to the benign nature
        # of includes that are not absolutely required.
        for i in xrange(len(marks)):
            if marks[i] == GOOD:
                marks[i] = TEST_OFF
                update_pch(filename, lines, marks)
                if not run(command):
                    # Revert.
                    marks[i] = GOOD
                else:
                    marks[i] = BAD
            elif marks[i] == TEST_OFF:
                marks[i] = TEST_ON

    update_pch(filename, lines, marks)

    log('')
    for i in xrange(len(marks)):
        if marks[i] == (BAD if FIND_CONFLICTS else GOOD):
            print("'{}',".format(get_filename(lines[i].strip('\n'))))

    return 0

if __name__ == '__main__':

    if len(sys.argv) in (3, 5):
        status = main()
        sys.exit(status)

    print('Usage: {} <pch> <command> [--find-conflicts]|[--find-required] [--verbose]\n'.format(sys.argv[0]))
    print('    --find-conflicts - Finds all conflicting includes. (Default)')
    print('                       Must compile without any includes.\n')
    print('    --find-required - Finds all required includes.')
    print('                      Must compile with all includes.\n')
    print('    --verbose - print noisy progress.')
    print('\nRunning unit-tests...')


class TestBisectConflict(unittest.TestCase):
    TEST = """ /* Test header. */
#include <memory>
#include <set>
#include <algorithm>
#include <vector>
/* blah blah */
"""
    BAD_LINE = "#include <bad>"

    def setUp(self):
        global FIND_CONFLICTS
        FIND_CONFLICTS = True

    def _update_func(self, lines, marks):
        self.lines = []
        for i in xrange(len(marks)):
            mark = marks[i]
            if mark <= TEST_ON:
                self.lines.append(lines[i])
            else:
                self.lines.append('//' + lines[i])

    def _test_func(self):
        """ Command function called by bisect.
            Returns True on Success, False on failure.
        """
        # If the bad line is still there, fail.
        return self.BAD_LINE not in self.lines

    def test_success(self):
        lines = self.TEST.split('\n')
        (marks, min, max) = get_marks(lines)
        marks = bisect(lines, marks, min, max,
                       lambda l, m: self._update_func(l, m),
                       lambda: self._test_func())
        self.assertTrue(BAD not in marks)

    def test_conflict(self):
        lines = self.TEST.split('\n')
        for pos in xrange(len(lines) + 1):
            lines = self.TEST.split('\n')
            lines.insert(pos, self.BAD_LINE)
            (marks, min, max) = get_marks(lines)

            marks = bisect(lines, marks, min, max,
                           lambda l, m: self._update_func(l, m),
                           lambda: self._test_func())
            for i in xrange(len(marks)):
                if i == pos:
                    self.assertEqual(BAD, marks[i])
                else:
                    self.assertNotEqual(BAD, marks[i])

class TestBisectRequired(unittest.TestCase):
    TEST = """#include <algorithm>
#include <set>
#include <map>
#include <vector>
"""
    REQ_LINE = "#include <req>"

    def setUp(self):
        global FIND_CONFLICTS
        FIND_CONFLICTS = False

    def _update_func(self, lines, marks):
        self.lines = []
        for i in xrange(len(marks)):
            mark = marks[i]
            if mark <= TEST_ON:
                self.lines.append(lines[i])
            else:
                self.lines.append('//' + lines[i])

    def _test_func(self):
        """ Command function called by bisect.
            Returns True on Success, False on failure.
        """
        # If the required line is not there, fail.
        found = self.REQ_LINE in self.lines
        return found

    def test_success(self):
        lines = self.TEST.split('\n')
        (marks, min, max) = get_marks(lines)
        marks = bisect(lines, marks, min, max,
                       lambda l, m: self._update_func(l, m),
                       lambda: self._test_func())
        self.assertTrue(GOOD not in marks)

    def test_required(self):
        lines = self.TEST.split('\n')
        for pos in xrange(len(lines) + 1):
            lines = self.TEST.split('\n')
            lines.insert(pos, self.REQ_LINE)
            (marks, min, max) = get_marks(lines)

            marks = bisect(lines, marks, min, max,
                           lambda l, m: self._update_func(l, m),
                           lambda: self._test_func())
            for i in xrange(len(marks)):
                if i == pos:
                    self.assertEqual(GOOD, marks[i])
                else:
                    self.assertNotEqual(GOOD, marks[i])

unittest.main()

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