"""Test Notebook signing"""

# Copyright (c) IPython Development Team.
# Distributed under the terms of the Modified BSD License.

import copy
import os
import shutil
import time
import tempfile
import testpath

from .base import TestsBase

from nbformat import read, sign

class TestNotary(TestsBase):
    
    def setUp(self):
        self.data_dir = tempfile.mkdtemp()
        self.notary = sign.NotebookNotary(
            db_file=':memory:',
            secret=b'secret',
            data_dir=self.data_dir,
        )
        with self.fopen(u'test3.ipynb', u'r') as f:
            self.nb = read(f, as_version=4)
        with self.fopen(u'test3.ipynb', u'r') as f:
            self.nb3 = read(f, as_version=3)
    
    def tearDown(self):
        shutil.rmtree(self.data_dir)
   
    def test_invalid_db_file(self):
        invalid_sql_file = os.path.join(self.data_dir, 'invalid_db_file.db')
        with open(invalid_sql_file, 'w') as tempfile:
            tempfile.write(u'[invalid data]')

        invalid_notary = sign.NotebookNotary(
            db_file=invalid_sql_file,
            secret=b'secret',
        )
        invalid_notary.sign(self.nb)

        testpath.assert_isfile(os.path.join(self.data_dir, invalid_sql_file))
        testpath.assert_isfile(os.path.join(self.data_dir, invalid_sql_file + '.bak'))
    
    def test_algorithms(self):
        last_sig = ''
        for algo in sign.algorithms:
            self.notary.algorithm = algo
            sig = self.notary.compute_signature(self.nb)
            self.assertNotEqual(last_sig, sig)
            last_sig = sig
    
    def test_sign_same(self):
        """Multiple signatures of the same notebook are the same"""
        sig1 = self.notary.compute_signature(self.nb)
        sig2 = self.notary.compute_signature(self.nb)
        self.assertEqual(sig1, sig2)
    
    def test_change_secret(self):
        """Changing the secret changes the signature"""
        sig1 = self.notary.compute_signature(self.nb)
        self.notary.secret = b'different'
        sig2 = self.notary.compute_signature(self.nb)
        self.assertNotEqual(sig1, sig2)
    
    def test_sign(self):
        self.assertFalse(self.notary.check_signature(self.nb))
        self.notary.sign(self.nb)
        self.assertTrue(self.notary.check_signature(self.nb))
    
    def test_unsign(self):
        self.notary.sign(self.nb)
        self.assertTrue(self.notary.check_signature(self.nb))
        self.notary.unsign(self.nb)
        self.assertFalse(self.notary.check_signature(self.nb))
        self.notary.unsign(self.nb)
        self.assertFalse(self.notary.check_signature(self.nb))
    
    def test_cull_db(self):
        # this test has various sleeps of 2ms
        # to ensure low resolution timestamps compare as expected
        dt = 2e-3
        nbs = [
            copy.deepcopy(self.nb) for i in range(10)
        ]
        for row in self.notary.db.execute("SELECT * FROM nbsignatures"):
            print(row)
        self.notary.cache_size = 8
        for i, nb in enumerate(nbs[:8]):
            nb.metadata.dirty = i
            self.notary.sign(nb)
        
        for i, nb in enumerate(nbs[:8]):
            time.sleep(dt)
            self.assertTrue(self.notary.check_signature(nb), 'nb %i is trusted' % i)
        
        # signing the 9th triggers culling of first 3
        # (75% of 8 = 6, 9 - 6 = 3 culled)
        self.notary.sign(nbs[8])
        self.assertFalse(self.notary.check_signature(nbs[0]))
        self.assertFalse(self.notary.check_signature(nbs[1]))
        self.assertFalse(self.notary.check_signature(nbs[2]))
        self.assertTrue(self.notary.check_signature(nbs[3]))
        # checking nb3 should keep it from being culled:
        self.notary.sign(nbs[0])
        self.notary.sign(nbs[1])
        self.notary.sign(nbs[2])
        self.assertTrue(self.notary.check_signature(nbs[3]))
        self.assertFalse(self.notary.check_signature(nbs[4]))
    
    def test_check_signature(self):
        nb = self.nb
        md = nb.metadata
        notary = self.notary
        check_signature = notary.check_signature
        # no signature:
        md.pop('signature', None)
        self.assertFalse(check_signature(nb))
        # hash only, no algo
        md.signature = notary.compute_signature(nb)
        self.assertFalse(check_signature(nb))
        # proper signature, algo mismatch
        notary.algorithm = 'sha224'
        notary.sign(nb)
        notary.algorithm = 'sha256'
        self.assertFalse(check_signature(nb))
        # check correctly signed notebook
        notary.sign(nb)
        self.assertTrue(check_signature(nb))
    
    def test_mark_cells_untrusted(self):
        cells = self.nb.cells
        self.notary.mark_cells(self.nb, False)
        for cell in cells:
            self.assertNotIn('trusted', cell)
            if cell.cell_type == 'code':
                self.assertIn('trusted', cell.metadata)
                self.assertFalse(cell.metadata.trusted)
            else:
                self.assertNotIn('trusted', cell.metadata)
    
    def test_mark_cells_trusted(self):
        cells = self.nb.cells
        self.notary.mark_cells(self.nb, True)
        for cell in cells:
            self.assertNotIn('trusted', cell)
            if cell.cell_type == 'code':
                self.assertIn('trusted', cell.metadata)
                self.assertTrue(cell.metadata.trusted)
            else:
                self.assertNotIn('trusted', cell.metadata)
    
    def test_check_cells(self):
        nb = self.nb
        self.notary.mark_cells(nb, True)
        self.assertTrue(self.notary.check_cells(nb))
        for cell in nb.cells:
            self.assertNotIn('trusted', cell)
        self.notary.mark_cells(nb, False)
        self.assertFalse(self.notary.check_cells(nb))
        for cell in nb.cells:
            self.assertNotIn('trusted', cell)
    
    def test_trust_no_output(self):
        nb = self.nb
        self.notary.mark_cells(nb, False)
        for cell in nb.cells:
            if cell.cell_type == 'code':
                cell.outputs = []
        self.assertTrue(self.notary.check_cells(nb))
    
    def test_mark_cells_untrusted_v3(self):
        nb = self.nb3
        cells = nb.worksheets[0].cells
        self.notary.mark_cells(nb, False)
        for cell in cells:
            self.assertNotIn('trusted', cell)
            if cell.cell_type == 'code':
                self.assertIn('trusted', cell.metadata)
                self.assertFalse(cell.metadata.trusted)
            else:
                self.assertNotIn('trusted', cell.metadata)
    
    def test_mark_cells_trusted_v3(self):
        nb = self.nb3
        cells = nb.worksheets[0].cells
        self.notary.mark_cells(nb, True)
        for cell in cells:
            self.assertNotIn('trusted', cell)
            if cell.cell_type == 'code':
                self.assertIn('trusted', cell.metadata)
                self.assertTrue(cell.metadata.trusted)
            else:
                self.assertNotIn('trusted', cell.metadata)
    
    def test_check_cells_v3(self):
        nb = self.nb3
        cells = nb.worksheets[0].cells
        self.notary.mark_cells(nb, True)
        self.assertTrue(self.notary.check_cells(nb))
        for cell in cells:
            self.assertNotIn('trusted', cell)
        self.notary.mark_cells(nb, False)
        self.assertFalse(self.notary.check_cells(nb))
        for cell in cells:
            self.assertNotIn('trusted', cell)

