# Copyright BigchainDB GmbH and BigchainDB contributors
# SPDX-License-Identifier: (Apache-2.0 AND CC-BY-4.0)
# Code is Apache-2.0 and docs are CC-BY-4.0

"""Query interfaces for backends."""

from functools import singledispatch

from bigchaindb.backend.exceptions import OperationError


@singledispatch
def store_asset(connection, asset):
    """Write an asset to the asset table.

    Args:
        asset (dict): the asset.

    Returns:
        The result of the operation.
    """

    raise NotImplementedError


@singledispatch
def store_assets(connection, assets):
    """Write a list of assets to the assets table.

    Args:
        assets (list): a list of assets to write.

    Returns:
        The database response.
    """

    raise NotImplementedError


@singledispatch
def store_metadatas(connection, metadata):
    """Write a list of metadata to metadata table.

    Args:
        metadata (list): list of metadata.

    Returns:
        The result of the operation.
    """

    raise NotImplementedError


@singledispatch
def store_transactions(connection, signed_transactions):
    """Store the list of transactions."""

    raise NotImplementedError


@singledispatch
def get_transaction(connection, transaction_id):
    """Get a transaction from the transactions table.

    Args:
        transaction_id (str): the id of the transaction.

    Returns:
        The result of the operation.
    """

    raise NotImplementedError


@singledispatch
def get_transactions(connection, transaction_ids):
    """Get transactions from the transactions table.

    Args:
        transaction_ids (list): list of transaction ids to fetch

    Returns:
        The result of the operation.
    """

    raise NotImplementedError


@singledispatch
def get_asset(connection, asset_id):
    """Get a transaction from the transactions table.

    Args:
        asset_id (str): the id of the asset

    Returns:
        The result of the operation.
    """

    raise NotImplementedError


@singledispatch
def get_spent(connection, transaction_id, condition_id):
    """Check if a `txid` was already used as an input.

    A transaction can be used as an input for another transaction. Bigchain
    needs to make sure that a given `txid` is only used once.

    Args:
        transaction_id (str): The id of the transaction.
        condition_id (int): The index of the condition in the respective
            transaction.

    Returns:
        The transaction that used the `txid` as an input else `None`
    """

    raise NotImplementedError


@singledispatch
def get_spending_transactions(connection, inputs):
    """Return transactions which spend given inputs

    Args:
        inputs (list): list of {txid, output}

    Returns:
        Iterator of (block_ids, transaction) for transactions that
        spend given inputs.
    """
    raise NotImplementedError


@singledispatch
def get_owned_ids(connection, owner):
    """Retrieve a list of `txids` that can we used has inputs.

    Args:
        owner (str): base58 encoded public key.

    Returns:
        Iterator of (block_id, transaction) for transactions
        that list given owner in conditions.
    """
    raise NotImplementedError


@singledispatch
def get_block(connection, block_id):
    """Get a block from the bigchain table.

    Args:
        block_id (str): block id of the block to get

    Returns:
        block (dict): the block or `None`
    """

    raise NotImplementedError


@singledispatch
def get_block_with_transaction(connection, txid):
    """Get a block containing transaction id `txid`

    Args:
        txid (str): id of transaction to be searched.

    Returns:
        block_id (int): the block id or `None`
    """

    raise NotImplementedError


@singledispatch
def get_metadata(connection, transaction_ids):
    """Get a list of metadata from the metadata table.

    Args:
        transaction_ids (list): a list of ids for the metadata to be retrieved from
        the database.

    Returns:
        metadata (list): the list of returned metadata.
    """
    raise NotImplementedError


@singledispatch
def get_assets(connection, asset_ids):
    """Get a list of assets from the assets table.
    Args:
        asset_ids (list): a list of ids for the assets to be retrieved from
        the database.
    Returns:
        assets (list): the list of returned assets.
    """
    raise NotImplementedError


@singledispatch
def get_txids_filtered(connection, asset_id, operation=None):
    """Return all transactions for a particular asset id and optional operation.

    Args:
        asset_id (str): ID of transaction that defined the asset
        operation (str) (optional): Operation to filter on
    """

    raise NotImplementedError


@singledispatch
def text_search(conn, search, *, language='english', case_sensitive=False,
                diacritic_sensitive=False, text_score=False, limit=0, table=None):
    """Return all the assets that match the text search.

    The results are sorted by text score.
    For more information about the behavior of text search on MongoDB see
    https://docs.mongodb.com/manual/reference/operator/query/text/#behavior

    Args:
        search (str): Text search string to query the text index
        language (str, optional): The language for the search and the rules for
            stemmer and tokenizer. If the language is ``None`` text search uses
            simple tokenization and no stemming.
        case_sensitive (bool, optional): Enable or disable case sensitive
            search.
        diacritic_sensitive (bool, optional): Enable or disable case sensitive
            diacritic search.
        text_score (bool, optional): If ``True`` returns the text score with
            each document.
        limit (int, optional): Limit the number of returned documents.

    Returns:
        :obj:`list` of :obj:`dict`: a list of assets

    Raises:
        OperationError: If the backend does not support text search
    """

    raise OperationError('This query is only supported when running '
                         'BigchainDB with MongoDB as the backend.')


@singledispatch
def get_latest_block(conn):
    """Get the latest commited block i.e. block with largest height"""

    raise NotImplementedError


@singledispatch
def store_block(conn, block):
    """Write a new block to the `blocks` table

    Args:
        block (dict): block with current height and block hash.

    Returns:
        The result of the operation.
    """

    raise NotImplementedError


@singledispatch
def store_unspent_outputs(connection, unspent_outputs):
    """Store unspent outputs in ``utxo_set`` table."""

    raise NotImplementedError


@singledispatch
def delete_unspent_outputs(connection, unspent_outputs):
    """Delete unspent outputs in ``utxo_set`` table."""

    raise NotImplementedError


@singledispatch
def delete_transactions(conn, txn_ids):
    """Delete transactions from database

    Args:
        txn_ids (list): list of transaction ids

    Returns:
        The result of the operation.
    """

    raise NotImplementedError


@singledispatch
def get_unspent_outputs(connection, *, query=None):
    """Retrieves unspent outputs.

    Args:
        query (dict): An optional parameter to filter the result set.
            Defaults to ``None``, which means that all UTXO records
            will be returned.

    Returns:
        Generator yielding unspent outputs (UTXO set) according to the
        given query.
    """

    raise NotImplementedError


@singledispatch
def store_pre_commit_state(connection, state):
    """Store pre-commit state.

    Args:
        state (dict): pre-commit state.

    Returns:
        The result of the operation.
    """

    raise NotImplementedError


@singledispatch
def get_pre_commit_state(connection):
    """Get pre-commit state.

    Returns:
        Document representing the pre-commit state.
    """

    raise NotImplementedError


@singledispatch
def store_validator_set(conn, validator_update):
    """Store updated validator set"""

    raise NotImplementedError


@singledispatch
def delete_validator_set(conn, height):
    """Delete the validator set at the given height."""

    raise NotImplementedError


@singledispatch
def store_election(conn, election_id, height, is_concluded):
    """Store election record"""

    raise NotImplementedError


@singledispatch
def store_elections(conn, elections):
    """Store election records in bulk"""

    raise NotImplementedError


@singledispatch
def delete_elections(conn, height):
    """Delete all election records at the given height"""

    raise NotImplementedError


@singledispatch
def get_validator_set(conn, height):
    """Get validator set for a given `height`, if `height` is not specified
    then return the latest validator set
    """

    raise NotImplementedError


@singledispatch
def get_election(conn, election_id):
    """Return the election record
    """

    raise NotImplementedError


@singledispatch
def get_asset_tokens_for_public_key(connection, asset_id, public_key):
    """Retrieve a list of tokens of type `asset_id` that are owned by the `public_key`.
    Args:
        asset_id (str): Id of the token.
        public_key (str): base58 encoded public key
    Returns:
        Iterator of transaction that list given owner in conditions.
    """
    raise NotImplementedError


@singledispatch
def store_abci_chain(conn, height, chain_id, is_synced=True):
    """Create or update an ABCI chain at the given height.
    Usually invoked in the beginning of the ABCI communications (height=0)
    or when ABCI client (like Tendermint) is migrated (any height).

    Args:
        is_synced: True if the chain is known by both ABCI client and server
    """

    raise NotImplementedError


@singledispatch
def delete_abci_chain(conn, height):
    """Delete the ABCI chain at the given height."""

    raise NotImplementedError


@singledispatch
def get_latest_abci_chain(conn):
    """Returns the ABCI chain stored at the biggest height, if any,
    None otherwise.
    """
    raise NotImplementedError