# -*- coding: utf-8 -*-

#

# PgDiff - capture differences of database metadata

#

# Depends on PgBrowser

#

# Copyright (c) 2011  Radek Brich <radek.brich@devl.cz>

#

# Permission is hereby granted, free of charge, to any person obtaining a copy

# of this software and associated documentation files (the "Software"), to deal

# in the Software without restriction, including without limitation the rights

# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell

# copies of the Software, and to permit persons to whom the Software is

# furnished to do so, subject to the following conditions:

#

# The above copyright notice and this permission notice shall be included in

# all copies or substantial portions of the Software.

#

# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE

# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,

# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN

# THE SOFTWARE.

class DiffBase:

    COLORS = {

        '+' : BOLD | GREEN,

        '-' : BOLD | RED,

        '*' : BOLD | YELLOW}

    def __init__(self):

        self.changes = None

    def format(self):

        out = ['  ' * self.level]

        out.append(highlight(1, self.COLORS[self.change]))

        out.append(self.change)

        out += [' ', self.type, ' ', self.name, highlight(0)]

        if self.changes:

            out += [highlight(1, WHITE), ' (', self.formatchanges(), ')', highlight(0)]

        return ''.join(out)

    def formatnotnull(self, notnull):

        if notnull:

            return 'NOT NULL'

        else:

            return None

    def formatchanges(self):

        res = []

        for x in self.changes:

            type, a, b = x

            if type == 'notnull':

                type = ''

                a = self.formatnotnull(a)

                b = self.formatnotnull(b)

            if a and b:

                s = ''.join(['Changed ', type, ' from ',

                    highlight(1,15), a, highlight(0), ' to ',

                    highlight(1,15), b, highlight(0), '.'])

            elif a and not b:

                l = ['Removed ']

                if type:

                    l += [type, ' ']

                l += [highlight(1,15), a, highlight(0), '.']

                s = ''.join(l)

            elif b and not a:

                l = ['Added ']

                if type:

                    l += [type, ' ']

                l += [highlight(1,15), b, highlight(0), '.']

                s = ''.join(l)

            res.append(s)

        return ' '.join(res)

class DiffSchema(DiffBase):

    def __init__(self, change, schema):

        DiffBase.__init__(self)

        self.level = 0

        self.type = 'schema'

        self.change = change

        self.schema = schema

        self.name = schema

class DiffTable(DiffBase):

    def __init__(self, change, schema, table):

        DiffBase.__init__(self)

        self.level = 1

        self.type = 'table'

        self.change = change

        self.schema = schema

        self.table = table

        self.name = table

class DiffColumn(DiffBase):

    def __init__(self, change, schema, table, column, changes=None):

        DiffBase.__init__(self)

        self.level = 2

        self.type = 'column'

        self.change = change

        self.schema = schema

        self.table = table

        self.column = column

        self.name = column

        self.changes = changes

class DiffConstraint(DiffBase):

    def __init__(self, change, schema, table, constraint, changes=None):

        DiffBase.__init__(self)

        self.level = 2

        self.type = 'constraint'

        self.change = change

        self.schema = schema

        self.table = table

        self.constraint = constraint

        self.name = constraint

        self.changes = changes

class PgDiff:

    def __init__(self, srcbrowser=None, dstbrowser=None):

        self.allowcolor = False

        self.src = srcbrowser

        self.dst = dstbrowser

        self.include_schemas = set()  # if not empty, consider only these schemas for diff

        self.exclude_schemas = set()  # exclude these schemas from diff

        self.include_tables = set()

        self.exclude_tables = set()

    def _test_filter(self, schema):

        if self.include_schemas and schema not in self.include_schemas:

            return False

        if schema in self.exclude_schemas:

            return False

        return True

    def _test_table(self, schema, table):

        name = schema + '.' + table

        if self.include_tables and name not in self.include_tables:

            return False

        if name in self.exclude_tables:

            return False

        return True 

    def _diffnames(self, src, dst):

        for x in src:

            if x in dst:

                yield ('*', x)

            else:

                yield ('-', x)

        for x in dst:

            if x not in src:

                yield ('+', x)

    def _compare_columns(self, a, b):

        diff = []

        if a.type != b.type:

            diff.append(('type', a.type, b.type))

        if a.notnull != b.notnull:

            diff.append(('notnull', a.notnull, b.notnull))

        if a.default != b.default:

            diff.append(('default', a.default, b.default))

        return diff

    def _compare_constraints(self, a, b):

        diff = []

        if a.type != b.type:

            diff.append(('type', a.type, b.type))

        if a.definition != b.definition:

            diff.append(('definition', a.definition, b.definition))

        return diff

    def _diff_columns(self, schema, table, src_columns, dst_columns):

        for nd in self._diffnames(src_columns, dst_columns):

            cdo = DiffColumn(change=nd[0], schema=schema, table=table, column=nd[1])

            if nd[0] == '*':

                a = src_columns[nd[1]]

                b = dst_columns[nd[1]]

                cdo.changes = self._compare_columns(a, b)

                if cdo.changes:

                    yield cdo

            else:

                yield cdo

    def _diff_constraints(self, schema, table, src_constraints, dst_constraints):

        for nd in self._diffnames(src_constraints, dst_constraints):

            cdo = DiffConstraint(change=nd[0], schema=schema, table=table, constraint=nd[1])

            if nd[0] == '*':

                a = src_constraints[nd[1]]

                b = dst_constraints[nd[1]]

                cdo.changes = self._compare_constraints(a, b)

                if cdo.changes:

                    yield cdo

            else:

                yield cdo

    def _difftables(self, schema, src_tables, dst_tables):

        for nd in self._diffnames(src_tables, dst_tables):

            if not self._test_table(schema, nd[1]):

                continue

            tdo = DiffTable(change=nd[0], schema=schema, table=nd[1])

            if nd[0] == '*':

                # columns

                src_columns = src_tables[nd[1]].columns

                dst_columns = dst_tables[nd[1]].columns

                for cdo in self._diff_columns(schema, nd[1], src_columns, dst_columns):

                    if tdo:

                        yield tdo

                        tdo = None

                    yield cdo

                # constraints

                src_constraints = src_tables[nd[1]].constraints

                dst_constraints = dst_tables[nd[1]].constraints

                for cdo in self._diff_constraints(schema, nd[1], src_constraints, dst_constraints):

                    if tdo:

                        yield tdo

                        tdo = None

                    yield cdo

            else:

                yield tdo

    def iter_diff(self):

        '''Return diff between src and dst database schema.

        Yields one line at the time. Each line is in form of object

        iherited from DiffBase. This object contains all information

        about changes. See format() method.

        '''

        src_schemas = self.src.schemas

        dst_schemas = self.dst.schemas

        src = [x.name for x in src_schemas.values() if not x.system and self._test_filter(x.name)]

        dst = [x.name for x in dst_schemas.values() if not x.system and self._test_filter(x.name)]

        for nd in self._diffnames(src, dst):

            sdo = DiffSchema(change=nd[0], schema=nd[1])

            if nd[0] == '*':

                src_tables = src_schemas[nd[1]].tables

                dst_tables = dst_schemas[nd[1]].tables

                for tdo in self._difftables(nd[1], src_tables, dst_tables):

                    if sdo:

                        yield sdo

                        sdo = None

                    yield tdo

            else:

                yield sdo

    def print_diff(self):

        '''Print diff between src and dst database schema.

        The output is in human readable form.

        Set allowcolor=True of PgDiff instance to get colored output. 

        '''

        for ln in self.iter_diff():

            print(ln.format())

    def print_patch(self):

        '''Print patch for updating from src schema to dst schema.

        Supports table drop, add, column drop, add and following

        changes of columns:

          - type

          - set/remove not null

          - default value

        This is experimental, not tested very much.

        Do not use without checking the commands.

        Even if it works as intended, it can cause table lock ups

        and/or loss of data. You have been warned.

        '''

        for ln in self.iter_diff():

            print(ln.format_patch())

    def filter_schemas(self, include=[], exclude=[]):

        '''Modify list of schemas which are used for computing diff.

        include (list) -- if not empty, consider only these schemas for diff

        exclude (list) -- exclude these schemas from diff

        Order: include, exclude

        include=[] means include everything

        '''

        self.include_schemas.clear()

        self.include_schemas.update(include)

        self.exclude_schemas.clear()

        self.exclude_schemas.update(exclude)

    def filter_tables(self, include=[], exclude=[]):

        self.include_tables.clear()

        self.include_tables.update(include)

        self.exclude_tables.clear()

        self.exclude_tables.update(exclude)