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

#

# PgBrowser - browse database schema and metadata

#

# Some of the queries came from psql.

#

# 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.

from collections import OrderedDict

class Column:

    def __init__(self, browser, table,

        name, type, notnull, hasdefault, default, description):

        self.browser = browser  # Browser instance

        self.table = table  # Table instance

        self.name = name

        self.type = type

        self.notnull = notnull

        self.hasdefault = hasdefault

        self.default = default

        self.description = description

class Constraint:

        self.browser = browser

        self.table = table

        self.name = name

        self.type = type

        self.definition = definition

class Index:

    def __init__(self, browser, table,

        name, primary, unique, clustered, valid, definition):

        self.browser = browser

        self.table = table

        self.name = name

        self.primary = primary

        self.unique = unique

        self.clustered = clustered

        self.valid = valid

        self.definition = definition

class Table:

    def __init__(self, browser, schema, name, owner, size, description):

        self._columns = None

        self._constraints = None

        self._indexes = None

        self.browser = browser  # Browser instance

        self.schema = schema  # Schema instance

        self.name = name  # table name, str

        self.owner = owner

        self.size = size

        self.description = description

    def refresh(self):

        self.refresh_columns()

        self.refresh_constraints()

        self.refresh_indexes()

    def refresh_columns(self):

        rows = self.browser.list_columns(self.name, self.schema.name)

        self._columns = OrderedDict([(x['name'], Column(self.browser, self, **x)) for x in rows])

    def refresh_constraints(self):

        rows = self.browser.list_constraints(self.name, self.schema.name)

        self._constraints = OrderedDict([(x['name'], Constraint(self.browser, self, **x)) for x in rows])

    def refresh_indexes(self):

        rows = self.browser.list_indexes(self.name, self.schema.name)

        self._indexes = OrderedDict([(x['name'], Index(self.browser, self, **x)) for x in rows])

    def getcolumns(self):

        if self._columns is None:

            self.refresh_columns()

        return self._columns

    columns = property(getcolumns)

    def getconstraints(self):

        if self._constraints is None:

            self.refresh_constraints()

        return self._constraints

    constraints = property(getconstraints)

    def getindexes(self):

        if self._indexes is None:

            self.refresh_indexes()

        return self._indexes

    indexes = property(getindexes)

class Schema:

    def __init__(self, browser, name, owner, acl, description, system):

        self._tables = None

        self.browser = browser

        self.name = name

        self.owner = owner

        self.acl = acl

        self.description = description

        self.system = system

    def refresh(self):

        rows = self.browser.list_tables(self.name)

        self._tables = OrderedDict([(x['name'], Table(self.browser, self, **x)) for x in rows]) 

    def gettables(self):

        if self._tables is None:

            self.refresh()

        return self._tables

    tables = property(gettables)

class PgBrowser:

    def __init__(self, conn=None):

        self._schemas = None

        self.conn = conn

    def setconn(self, conn=None):

        self.conn = conn

    def refresh(self):

        rows = self.list_schemas()

        self._schemas = OrderedDict([(x['name'], Schema(self, **x)) for x in rows])

    def getschemas(self):

        if self._schemas is None:

            self.refresh()

        return self._schemas

    schemas = property(getschemas)

    def _query(self, query, args):

        try:

            curs = self.conn.cursor()

            curs.execute(query, args)

            curs.connection.commit()

            rows = curs.fetchall()

            return [dict(zip([desc[0] for desc in curs.description], row)) for row in rows]

        finally:

            curs.close()

    def list_databases(self):

        return self._query('''

            SELECT

                d.datname as "name",

                pg_catalog.pg_get_userbyid(d.datdba) as "owner",

                pg_catalog.pg_encoding_to_char(d.encoding) as "encoding",

                d.datcollate as "collation",

                d.datctype as "ctype",

                d.datacl AS "acl",

                CASE WHEN pg_catalog.has_database_privilege(d.datname, 'CONNECT')

                    THEN pg_catalog.pg_database_size(d.datname)

                    ELSE -1 -- No access

                END as "size",

                t.spcname as "tablespace",

                pg_catalog.shobj_description(d.oid, 'pg_database') as "description"

            FROM pg_catalog.pg_database d

            JOIN pg_catalog.pg_tablespace t on d.dattablespace = t.oid

            ORDER BY 1;

            ''', [])

    def list_schemas(self):

        return self._query('''

            SELECT

                n.nspname AS "name",

                pg_catalog.pg_get_userbyid(n.nspowner) AS "owner",

                n.nspacl AS "acl",

                pg_catalog.obj_description(n.oid, 'pg_namespace') AS "description",

                CASE WHEN n.nspname IN ('information_schema', 'pg_catalog', 'pg_toast')

                    OR n.nspname ~ '^pg_temp_' OR n.nspname ~ '^pg_toast_temp_'

                    THEN TRUE

                    ELSE FALSE

                END AS "system"

            FROM pg_catalog.pg_namespace n

            ORDER BY 1;

            ''', [])

    def list_tables(self, schema='public'):

        return self._query('''

            SELECT

                c.relname as "name",

                pg_catalog.pg_get_userbyid(c.relowner) as "owner",

                pg_catalog.pg_relation_size(c.oid) as "size",

                pg_catalog.obj_description(c.oid, 'pg_class') as "description"

            FROM pg_catalog.pg_class c

            LEFT JOIN pg_catalog.pg_namespace n ON n.oid = c.relnamespace

            WHERE n.nspname = %s AND c.relkind IN ('r','s','')

            ORDER BY 1;

            ''', [schema])

    def list_columns(self, table, schema='public', order=2):

        return self._query('''

            SELECT

                a.attname as "name",

                format_type(a.atttypid, a.atttypmod) AS "type",

                a.attnotnull as "notnull",

                a.atthasdef as "hasdefault",

                d.adsrc as "default",

                pg_catalog.col_description(a.attrelid, a.attnum) AS "description"

            FROM pg_catalog.pg_attribute a

            LEFT JOIN pg_catalog.pg_class c ON a.attrelid = c.oid

            LEFT JOIN pg_catalog.pg_namespace n ON n.oid = c.relnamespace

            LEFT JOIN pg_catalog.pg_attrdef d ON a.attrelid = d.adrelid AND a.attnum = d.adnum

            WHERE n.nspname = %s AND c.relname = %s AND a.attnum > 0 AND NOT a.attisdropped

            ORDER BY ''' + str(order), [schema, table])

    def list_constraints(self, table, schema='public'):

        return self._query('''

            SELECT

                r.conname AS "name",

                r.contype AS "type",

                cf.relname AS "fname",

                nf.nspname AS "fschema",

                pg_catalog.pg_get_constraintdef(r.oid, true) as "definition"

            FROM pg_catalog.pg_constraint r

            JOIN pg_catalog.pg_class c ON r.conrelid = c.oid

            JOIN pg_catalog.pg_namespace n ON n.oid = c.relnamespace

            LEFT JOIN pg_catalog.pg_class cf ON r.confrelid = cf.oid

            LEFT JOIN pg_catalog.pg_namespace nf ON nf.oid = cf.relnamespace

            WHERE n.nspname = %s AND c.relname = %s

            ORDER BY 1

            ''', [schema, table])

    def list_indexes(self, table, schema='public'):

        return self._query('''

            SELECT

                c2.relname as "name",

                i.indisprimary as "primary",

                i.indisunique as "unique",

                i.indisclustered as "clustered",

                i.indisvalid as "valid",

                pg_catalog.pg_get_indexdef(i.indexrelid, 0, true) as "definition",

                ARRAY(SELECT a.attname FROM pg_catalog.pg_attribute a WHERE a.attrelid = c2.oid ORDER BY attnum) AS "columns"

                --c2.reltablespace as "tablespace_oid"

            FROM pg_catalog.pg_class c

            JOIN pg_catalog.pg_index i ON c.oid = i.indrelid

            JOIN pg_catalog.pg_class c2 ON i.indexrelid = c2.oid

            JOIN pg_catalog.pg_namespace n ON n.oid = c.relnamespace

            WHERE n.nspname = %(schema)s AND c.relname = %(table)s

            ORDER BY i.indisprimary DESC, i.indisunique DESC, c2.relname

            ''', {'schema': schema, 'table': table})

    def list_column_usage(self, table, column, schema='public'):

        '''List objects using the column.

        Currently shows views and constraints which use the column.

        This is useful to find which views block alteration of column type etc.

        '''

        return self._query('''

            SELECT

                'view' AS type, view_schema AS schema, view_name AS name

            FROM information_schema.view_column_usage

            WHERE table_schema=%(schema)s AND table_name=%(table)s AND column_name=%(column)s

            UNION

            SELECT

                'constraint' AS type, constraint_schema AS schema, constraint_name AS name

            FROM information_schema.constraint_column_usage

            WHERE table_schema=%(schema)s AND table_name=%(table)s AND column_name=%(column)s

            ''', {'schema':schema, 'table':table, 'column':column})