"""
opentrons.protocols.parse: functions and state for parsing protocols
"""

import ast
import functools
import itertools
import json
import logging
import re
from io import BytesIO
from zipfile import ZipFile
from typing import Any, Dict, Optional, Union, Tuple, TYPE_CHECKING

import jsonschema  # type: ignore

from opentrons.config import feature_flags as ff
from opentrons_shared_data import load_shared_data, protocol
from .types import (Protocol, PythonProtocol, JsonProtocol,
                    Metadata, APIVersion, MalformedProtocolError)
from .bundle import extract_bundle

if TYPE_CHECKING:
    from opentrons_shared_data.labware.dev_types import LabwareDefinition
    from opentrons_shared_data.protocol.dev_types import (
        JsonProtocol as JsonProtocolDef
    )

MODULE_LOG = logging.getLogger(__name__)

# match e.g. "2.0" but not "hi", "2", "2.0.1"
API_VERSION_RE = re.compile(r'^(\d+)\.(\d+)$')
MAX_SUPPORTED_JSON_SCHEMA_VERSION = 5


def _validate_v2_ast(protocol_ast: ast.Module):
    defs = [fdef for fdef in protocol_ast.body
            if isinstance(fdef, ast.FunctionDef)]
    rundefs = [fdef for fdef in defs
               if fdef.name == 'run']
    # There must be precisely 1 one run function
    if len(rundefs) > 1:
        lines = [str(d.lineno) for d in rundefs]
        linestr = ', '.join(lines)
        raise MalformedProtocolError(
            f'More than one run function is defined (lines {linestr})')
    if not rundefs:
        raise MalformedProtocolError(
            "No function 'run(ctx)' defined")
    if infer_version_from_imports(protocol_ast):
        raise MalformedProtocolError(
            'Protocol API v1 modules such as robot, instruments, and labware '
            'may not be imported in Protocol API V2 protocols'
        )


def version_from_string(vstr: str) -> APIVersion:
    """ Parse an API version from a string

    :param str vstr: The version string to parse
    :returns APIVersion: The parsed version
    :raises ValueError: if the version string is the wrong format
    """
    matches = API_VERSION_RE.match(vstr)
    if not matches:
        raise ValueError(
            f'apiLevel {vstr} is incorrectly formatted. It should '
            'major.minor, where both major and minor are numbers.')
    return APIVersion(
        major=int(matches.group(1)), minor=int(matches.group(2)))


def _parse_json(
        protocol_contents: str, filename: str = None) -> JsonProtocol:
    """ Parse a protocol known or at least suspected to be json """
    protocol_json = json.loads(protocol_contents)
    version, validated = validate_json(protocol_json)
    return JsonProtocol(
        text=protocol_contents, filename=filename, contents=validated,
        schema_version=version)


def _parse_python(
    protocol_contents: str,
    filename: str = None,
    bundled_labware: Dict[str, 'LabwareDefinition'] = None,
    bundled_data: Dict[str, bytes] = None,
    bundled_python: Dict[str, str] = None,
    extra_labware: Dict[str, 'LabwareDefinition'] = None,
) -> PythonProtocol:
    """ Parse a protocol known or at least suspected to be python """
    filename_checked = filename or '<protocol>'
    if filename_checked.endswith('.zip'):
        ast_filename = 'protocol.ot2.py'
    else:
        ast_filename = filename_checked

    parsed = ast.parse(protocol_contents,
                       filename=ast_filename)

    metadata = extract_metadata(parsed)
    protocol = compile(parsed, filename=ast_filename, mode='exec')
    version = get_version(metadata, parsed)

    if version >= APIVersion(2, 0):
        _validate_v2_ast(parsed)

    result = PythonProtocol(
        text=protocol_contents,
        filename=getattr(protocol, 'co_filename', '<protocol>'),
        contents=protocol,
        metadata=metadata,
        api_level=version,
        bundled_labware=bundled_labware,
        bundled_data=bundled_data,
        bundled_python=bundled_python,
        extra_labware=extra_labware)

    return result


def _parse_bundle(bundle: ZipFile, filename: str = None) -> PythonProtocol:  # noqa: C901
    """ Parse a bundled Python protocol """
    if not ff.use_protocol_api_v2():
        raise RuntimeError(
            'Uploading a bundled protocol requires the robot to be set to '
            'Protocol API V2. Enable the \'Use Protocol API version 2\' '
            'toggle in the robot\'s Advanced Settings and restart the robot')

    contents = extract_bundle(bundle)

    result = _parse_python(
        contents.protocol, filename,
        contents.bundled_labware,
        contents.bundled_data,
        contents.bundled_python)

    if result.api_level < APIVersion(2, 0):
        raise RuntimeError('Bundled protocols must use Protocol API V2, ' +
                           f'got {result.api_level}')

    return result


def parse(
    protocol_file: Union[str, bytes],
    filename: str = None,
    extra_labware: Dict[str, 'LabwareDefinition'] = None,
    extra_data: Dict[str, bytes] = None
) -> Protocol:
    """ Parse a protocol from text.

    :param protocol_file: The protocol file, or for single-file protocols, a
                        string of the protocol contents.
    :param filename: The name of the protocol. Optional, but helps with
                     deducing the kind of protocol (e.g. if it ends with
                     '.json' we can treat it like json)
    :param extra_labware: Any extra labware defs that should be given to the
                          protocol. Ignored if the protocol is json or zipped
                          python.
    :param extra_data: Any extra data files that should be provided to the
                       protocol. Ignored if the protocol is json or zipped
                       python.
    :return types.Protocol: The protocol holder, a named tuple that stores the
                        data in the protocol for later simulation or
                        execution.
    """
    if filename and filename.endswith('.zip'):
        if not isinstance(protocol_file, bytes):
            raise RuntimeError('Please update your Run App version to '
                               'support uploading a .zip file')

        with ZipFile(BytesIO(protocol_file)) as bundle:
            result = _parse_bundle(bundle, filename)
        return result
    else:
        if isinstance(protocol_file, bytes):
            protocol_str = protocol_file.decode('utf-8')
        else:
            protocol_str = protocol_file

        if filename and filename.endswith('.json'):
            return _parse_json(protocol_str, filename)
        elif filename and filename.endswith('.py'):
            return _parse_python(
                protocol_str, filename, extra_labware=extra_labware,
                bundled_data=extra_data)

        # our jsonschema says the top level json kind is object
        if protocol_str and protocol_str[0] in ('{', b'{'):
            return _parse_json(protocol_str, filename)
        else:
            return _parse_python(
                protocol_str, filename, extra_labware=extra_labware,
                bundled_data=extra_data)


def extract_metadata(parsed: ast.Module) -> Metadata:
    metadata: Metadata = {}
    assigns = [
        obj for obj in parsed.body if isinstance(obj, ast.Assign)]
    for obj in assigns:
        # XXX This seems brittle and could probably do with
        # - enough love that we can remove the type: ignores
        # - some thought about exactly what types are allowed in metadata
        if isinstance(obj.targets[0], ast.Name) \
                and obj.targets[0].id == 'metadata' \
                and isinstance(obj.value, ast.Dict):
            keys = [k.s for k in obj.value.keys]  # type: ignore
            values = [v.s for v in obj.value.values]  # type: ignore
            metadata = dict(zip(keys, values))
    return metadata


@functools.lru_cache(1)
def infer_version_from_imports(parsed: ast.Module) -> Optional[APIVersion]:
    # Imports in the form of `import opentrons.robot` will have an entry in
    # parsed.body[i].names[j].name in the form "opentrons.robot". Find those
    # imports and transform them to strip away the 'opentrons.' part.
    ot_imports = ['.'.join(name.name.split('.')[1:]) for name in
                  itertools.chain.from_iterable(
                      [obj.names for obj in parsed.body
                       if isinstance(obj, ast.Import)])
                  if 'opentrons' in name.name]

    # Imports in the form of `from opentrons import robot` (with or without an
    # `as ___` statement) will have an entry in parsed.body[i].module
    # containing "opentrons"
    ot_from_imports = [
        name.name for name in
        itertools.chain.from_iterable(
            [obj.names for obj in parsed.body
             if isinstance(obj, ast.ImportFrom)
             and obj.module
             and 'opentrons' in obj.module])
    ]

    # If any of these are populated, filter for entries with v1-specific terms
    opentrons_imports = set(ot_imports + ot_from_imports)
    v1_markers = set(('robot', 'instruments', 'modules', 'containers'))
    v1evidence = v1_markers.intersection(opentrons_imports)
    if v1evidence:
        return APIVersion(1, 0)
    else:
        return None


def version_from_metadata(metadata: Metadata) -> APIVersion:
    """ Build an API version from metadata, if we can.

    If there is no apiLevel key, raise a KeyError.
    If the apiLevel value is malformed, raise a ValueError.
    """
    if 'apiLevel' not in metadata:
        raise KeyError('apiLevel')
    requested_level = str(metadata['apiLevel'])
    if requested_level == '1':
        return APIVersion(1, 0)

    return version_from_string(requested_level)


def get_version(metadata: Metadata, parsed: ast.Module) -> APIVersion:
    """
    Infer protocol API version based on a combination of metadata and imports.

    If a protocol specifies its API version using the 'apiLevel' key of a top-
    level dict variable named `metadata`, the value for that key will be
    returned as the version (the value will be intified, so numeric values
    only can be used).

    If that variable does not exist or if it does not contain the 'apiLevel'
    key, the API version will be inferred from the imports. A script with an
    import containing 'robot', 'instruments', or 'modules' will be assumed to
    be an APIv1 protocol. If none of these are present, it is assumed to be an
    APIv2 protocol (note that 'labware' is not in this list, as there is a
    valid APIv2 import named 'labware').
    """
    try:
        return version_from_metadata(metadata)
    except KeyError:  # No apiLevel key, may be apiv1
        pass
    inferred = infer_version_from_imports(parsed)
    if not inferred:
        raise RuntimeError(
            'If this is not an API v1 protocol, you must specify the target '
            'api level in the apiLevel key of the metadata. For instance, '
            'metadata={"apiLevel": "2.0"}')
    return inferred


def _get_protocol_schema_version(protocol_json: Dict[Any, Any]) -> int:
    # v3 and above uses `schemaVersion: integer`
    version = protocol_json.get('schemaVersion')
    if version:
        return int(version)
    # v1 uses 1.x.x and v2 uses 2.x.x
    legacyKebabVersion = protocol_json.get('protocol-schema')
    # No minor/patch schemas ever were released,
    # do not permit protocols with nonexistent schema versions to load
    if legacyKebabVersion == '1.0.0':
        return 1
    elif legacyKebabVersion == '2.0.0':
        return 2
    elif legacyKebabVersion:
        raise RuntimeError(
            f'No such schema version: "{legacyKebabVersion}". Did you mean ' +
            '"1.0.0" or "2.0.0"?')
    # no truthy value for schemaVersion or protocol-schema
    raise RuntimeError(
        'Could not determine schema version for protocol. ' +
        'Make sure there is a version number under "schemaVersion"')


def _get_schema_for_protocol(version_num: int) -> protocol.Schema:
    """ Retrieve the json schema for a protocol schema version
    """
    # TODO(IL, 2020/03/05): use $otSharedSchema, but maybe wait until
    # deprecating v1/v2 JSON protocols?
    if version_num > MAX_SUPPORTED_JSON_SCHEMA_VERSION:
        raise RuntimeError(
            f'JSON Protocol version {version_num} is not yet ' +
            'supported in this version of the API')
    try:
        schema = load_shared_data(
            f'protocol/schemas/{version_num}.json')
    except FileNotFoundError:
        schema = None  # type: ignore
    if not schema:
        raise RuntimeError('JSON Protocol schema "{}" does not exist'
                           .format(version_num))
    return json.loads(schema.decode('utf-8'))


def validate_json(
        protocol_json: Dict[Any, Any]) -> Tuple[int, 'JsonProtocolDef']:
    """ Validates a json protocol and returns its schema version """
    # Check if this is actually a labware
    labware_schema_v2 = json.loads(load_shared_data(
        'labware/schemas/2.json').decode('utf-8'))
    try:
        jsonschema.validate(protocol_json, labware_schema_v2)
    except jsonschema.ValidationError:
        pass
    else:
        MODULE_LOG.error("labware uploaded instead of protocol")
        raise RuntimeError(
            'The file you are trying to open is a JSON labware definition, '
            'and therefore can not be opened here. Please try '
            'uploading a JSON protocol file instead.')

    # this is now either a protocol or something corrupt
    version_num = _get_protocol_schema_version(protocol_json)
    if version_num <= 2:
        raise RuntimeError(
            f'JSON protocol version {version_num} is '
            'deprecated. Please upload your protocol into Protocol '
            'Designer and save it to migrate the protocol to a later '
            'version. This error might mean a labware '
            'definition was specified instead of a protocol.')
    if version_num > MAX_SUPPORTED_JSON_SCHEMA_VERSION:
        raise RuntimeError(
            f'The protocol you are trying to open is a JSONv{version_num} '
            'protocol and is not supported by your current robot server '
            'version. Please update your OT-2 App and robot server to the '
            'latest version and try again.'
        )
    protocol_schema = _get_schema_for_protocol(version_num)

    # instruct schema how to resolve all $ref's used in protocol schemas
    resolver = jsonschema.RefResolver(
        protocol_schema.get('$id', ''),
        protocol_schema,
        store={