import argparse
import io
import urllib.parse
import zipfile
from functools import partial
from pathlib import Path
from sys import argv, stdout, stderr

import requests

from . import Command
from .server import report_configuration
from ..service.db import dump_db, exp_drop, exp_db_exist, exp_duplicate_database, exp_rename, restore_db
from ..tools import config

eprint = partial(print, file=stderr, flush=True)

class Db(Command):
    name = 'db'

    def run(self, cmdargs):
        """Command-line version of the database manager.

        Doesn't provide a `create` command as that's not useful. Commands are
        all filestore-aware.
        """
        parser = argparse.ArgumentParser(
            prog="%s %s" % (Path(argv[0]).name, self.name),
            description=self.__doc__
        )
        parser.add_argument('-c', '--config')
        parser.add_argument('-D', '--data-dir')
        parser.add_argument('--addons-path')
        parser.add_argument('-r', '--db_user')
        parser.add_argument('-w', '--db_password')
        parser.add_argument('--pg_path')
        parser.add_argument('--db_host')
        parser.add_argument('--db_port')
        parser.add_argument('--db_sslmode')
        parser.set_defaults(func=lambda _: exit(parser.format_help()))

        subs = parser.add_subparsers()
        load = subs.add_parser(
            "load", help="Load a dump file.",
            description="Loads a dump file into odoo, dump file can be a URL. "
                 "If `database` is provided, uses that as the database name. "
                 "Otherwise uses the dump file name without extension.")
        load.set_defaults(func=self.load)
        load.add_argument(
            '-f', '--force', action='store_const', default=False, const=True,
            help="delete `database` database before loading if it exists"
        )
        load.add_argument(
            'database', nargs='?',
            help="database to create, defaults to dump file's name "
                 "(without extension)"
        )
        load.add_argument('dump_file', help="zip or pg_dump file to load")

        dump = subs.add_parser(
            "dump", help="Create a dump with filestore.",
            description="Creates a dump file. The dump is always in zip format "
                        "(with filestore), to get a no-filestore format use "
                        "pg_dump directly.")
        dump.set_defaults(func=self.dump)
        dump.add_argument('database', help="database to dump")
        dump.add_argument(
            'dump_path', nargs='?', default='-',
            help="if provided, database is dumped to specified path, otherwise "
                 "or if `-`, dumped to stdout",
        )

        duplicate = subs.add_parser("duplicate", help="Duplicate a database including filestore.")
        duplicate.set_defaults(func=self.duplicate)
        duplicate.add_argument(
            '-f', '--force', action='store_const', default=False, const=True,
            help="delete `target` database before copying if it exists"
        )
        duplicate.add_argument("source")
        duplicate.add_argument("target", help="database to copy `source` to, must not exist unless `-f` is specified in which case it will be dropped first")

        rename = subs.add_parser("rename", help="Rename a database including filestore.")
        rename.set_defaults(func=self.rename)
        rename.add_argument(
            '-f', '--force', action='store_const', default=False, const=True,
            help="delete `target` database before renaming if it exists"
        )
        rename.add_argument('source')
        rename.add_argument("target", help="database to rename `source` to, must not exist unless `-f` is specified, in which case it will be dropped first")

        drop = subs.add_parser("drop", help="Delete a database including filestore")
        drop.set_defaults(func=self.drop)
        drop.add_argument("database", help="database to delete")

        args = parser.parse_args(cmdargs)

        config.parse_config([
            val
            for k, v in vars(args).items()
            if v is not None
            if k in ['config', 'data_dir', 'addons_path'] or k.startswith(('db_', 'pg_'))
            for val in [
                '--data-dir' if k == 'data_dir'\
                    else '--addons-path' if k == 'addons_path'\
                    else f'--{k}',
                v,
            ]
        ])
        # force db management active to bypass check when only a
        # `check_db_management_enabled` version is available.
        config['list_db'] = True
        report_configuration()

        args.func(args)

    def load(self, args):
        db_name = args.database or Path(args.dump_file).stem
        self._check_target(db_name, delete_if_exists=args.force)

        url = urllib.parse.urlparse(args.dump_file)
        if url.scheme:
            eprint(f"Fetching {args.dump_file}...", end='')
            r = requests.get(args.dump_file, timeout=10)
            if not r.ok:
                exit(f" unable to fetch {args.dump_file}: {r.reason}")

            eprint(" done")
            dump_file = io.BytesIO(r.content)
        else:
            eprint(f"Restoring {args.dump_file}...")
            dump_file = args.dump_file

        if not zipfile.is_zipfile(dump_file):
            exit("Not a zipped dump file, use `pg_restore` to restore raw dumps,"
                 " and `psql` to execute sql dumps or scripts.")

        restore_db(db=db_name, dump_file=dump_file, copy=True)

    def dump(self, args):
        if args.dump_path == '-':
            dump_db(args.database, stdout.buffer)
        else:
            with open(args.dump_path, 'wb') as f:
                dump_db(args.database, f)

    def duplicate(self, args):
        self._check_target(args.target, delete_if_exists=args.force)
        exp_duplicate_database(args.source, args.target)

    def rename(self, args):
        self._check_target(args.target, delete_if_exists=args.force)
        exp_rename(args.source, args.target)

    def drop(self, args):
        if not exp_drop(args.database):
            exit(f"Database {args.database} does not exist.")

    def _check_target(self, target, *, delete_if_exists):
        if exp_db_exist(target):
            if delete_if_exists:
                exp_drop(target)
            else:
                exit(f"Target database {target} exists, aborting.\n\n"
                     f"\tuse `--force` to delete the existing database anyway.")