import logging
import math
import re
import sys

from .exceptions import PapermillException
from .models import Parameter


logger = logging.getLogger(__name__)


class PapermillTranslators(object):
    '''
    The holder which houses any translator registered with the system.
    This object is used in a singleton manner to save and load particular
    named Translator objects for reference externally.
    '''

    def __init__(self):
        self._translators = {}

    def register(self, language, translator):
        self._translators[language] = translator

    def find_translator(self, kernel_name, language):
        if kernel_name in self._translators:
            return self._translators[kernel_name]
        elif language in self._translators:
            return self._translators[language]
        raise PapermillException(
            "No parameter translator functions specified for kernel '{}' or language '{}'".format(
                kernel_name, language
            )
        )


class Translator(object):
    @classmethod
    def translate_raw_str(cls, val):
        """Reusable by most interpreters"""
        return '{}'.format(val)

    @classmethod
    def translate_escaped_str(cls, str_val):
        """Reusable by most interpreters"""
        if isinstance(str_val, str):
            str_val = str_val.encode('unicode_escape')
            if sys.version_info >= (3, 0):
                str_val = str_val.decode('utf-8')
            str_val = str_val.replace('"', r'\"')
        return '"{}"'.format(str_val)

    @classmethod
    def translate_str(cls, val):
        """Default behavior for translation"""
        return cls.translate_escaped_str(val)

    @classmethod
    def translate_none(cls, val):
        """Default behavior for translation"""
        return cls.translate_raw_str(val)

    @classmethod
    def translate_int(cls, val):
        """Default behavior for translation"""
        return cls.translate_raw_str(val)

    @classmethod
    def translate_float(cls, val):
        """Default behavior for translation"""
        return cls.translate_raw_str(val)

    @classmethod
    def translate_bool(cls, val):
        """Default behavior for translation"""
        return 'true' if val else 'false'

    @classmethod
    def translate_dict(cls, val):
        raise NotImplementedError('dict type translation not implemented for {}'.format(cls))

    @classmethod
    def translate_list(cls, val):
        raise NotImplementedError('list type translation not implemented for {}'.format(cls))

    @classmethod
    def translate(cls, val):
        """Translate each of the standard json/yaml types to appropiate objects."""
        if val is None:
            return cls.translate_none(val)
        elif isinstance(val, str):
            return cls.translate_str(val)
        # Needs to be before integer checks
        elif isinstance(val, bool):
            return cls.translate_bool(val)
        elif isinstance(val, int):
            return cls.translate_int(val)
        elif isinstance(val, float):
            return cls.translate_float(val)
        elif isinstance(val, dict):
            return cls.translate_dict(val)
        elif isinstance(val, list):
            return cls.translate_list(val)
        # Use this generic translation as a last resort
        return cls.translate_escaped_str(val)

    @classmethod
    def comment(cls, cmt_str):
        raise NotImplementedError('comment translation not implemented for {}'.format(cls))

    @classmethod
    def assign(cls, name, str_val):
        return '{} = {}'.format(name, str_val)

    @classmethod
    def codify(cls, parameters, comment='Parameters'):
        content = '{}\n'.format(cls.comment(comment))
        for name, val in parameters.items():
            content += '{}\n'.format(cls.assign(name, cls.translate(val)))
        return content

    @classmethod
    def inspect(cls, parameters_cell):
        """Inspect the parameters cell to get a Parameter list

        It must return an empty list if no parameters are found and
        it should ignore inspection errors.

        .. note::
            ``inferred_type_name`` should be "None" if unknown (set it
            to "NoneType" for null value)

        Parameters
        ----------
        parameters_cell : NotebookNode
            Cell tagged _parameters_

        Returns
        -------
        List[Parameter]
            A list of all parameters
        """
        raise NotImplementedError('parameters introspection not implemented for {}'.format(cls))


class PythonTranslator(Translator):
    # Pattern to capture parameters within cell input
    PARAMETER_PATTERN = re.compile(
        r"^(?P<target>\w[\w_]*)\s*(:\s*[\"']?(?P<annotation>\w[\w_\[\],\s]*)[\"']?\s*)?=\s*(?P<value>.*?)(\s*#\s*(type:\s*(?P<type_comment>[^\s]*)\s*)?(?P<help>.*))?$"  # noqa
    )

    @classmethod
    def translate_float(cls, val):
        if math.isfinite(val):
            return cls.translate_raw_str(val)
        elif math.isnan(val):
            return "float('nan')"
        elif val < 0:
            return "float('-inf')"
        else:
            return "float('inf')"

    @classmethod
    def translate_bool(cls, val):
        return cls.translate_raw_str(val)

    @classmethod
    def translate_dict(cls, val):
        escaped = ', '.join(
            ["{}: {}".format(cls.translate_str(k), cls.translate(v)) for k, v in val.items()]
        )
        return '{{{}}}'.format(escaped)

    @classmethod
    def translate_list(cls, val):
        escaped = ', '.join([cls.translate(v) for v in val])
        return '[{}]'.format(escaped)

    @classmethod
    def comment(cls, cmt_str):
        return '# {}'.format(cmt_str).strip()

    @classmethod
    def codify(cls, parameters, comment='Parameters'):
        content = super(PythonTranslator, cls).codify(parameters, comment)
        if sys.version_info >= (3, 6):
            try:
                # Put content through the Black Python code formatter
                import black

                fm = black.FileMode(string_normalization=False)
                content = black.format_str(content, mode=fm)
            except ImportError:
                logger.warning("Black is not installed, parameters wont be formatted")
        return content

    @classmethod
    def inspect(cls, parameters_cell):
        """Inspect the parameters cell to get a Parameter list

        It must return an empty list if no parameters are found and
        it should ignore inspection errors.

        Parameters
        ----------
        parameters_cell : NotebookNode
            Cell tagged _parameters_

        Returns
        -------
        List[Parameter]
            A list of all parameters
        """
        params = []
        src = parameters_cell['source']

        def flatten_accumulator(accumulator):
            """Flatten a multilines variable definition.

            Remove all comments except on the latest line - will be interpreted as help.

            Args:
                accumulator (List[str]): Line composing the variable definition
            Returns:
                Flatten definition
            """
            flat_string = ""
            for line in accumulator[:-1]:
                if "#" in line:
                    comment_pos = line.index("#")
                    flat_string += line[:comment_pos].strip()
                else:
                    flat_string += line.strip()
            if len(accumulator):
                flat_string += accumulator[-1].strip()
            return flat_string

        # Some common type like dictionaries or list can be expressed over multiline.
        # To support the parsing of such case, the cell lines are grouped between line
        # actually containing an assignment. In each group, the commented and empty lines
        # are skip; i.e. the parameter help can only be given as comment on the last variable
        # line definition
        grouped_variable = []
        accumulator = []
        for iline, line in enumerate(src.splitlines()):
            if len(line.strip()) == 0 or line.strip().startswith('#'):
                continue  # Skip blank and comment

            nequal = line.count("=")
            if nequal > 0:
                grouped_variable.append(flatten_accumulator(accumulator))
                accumulator = []
                if nequal > 1:
                    logger.warning("Unable to parse line {} '{}'.".format(iline + 1, line))
                    continue

            accumulator.append(line)
        grouped_variable.append(flatten_accumulator(accumulator))

        for definition in grouped_variable:
            if len(definition) == 0:
                continue

            match = re.match(cls.PARAMETER_PATTERN, definition)
            if match is not None:
                attr = match.groupdict()
                if attr["target"] is None:  # Fail to get variable name
                    continue

                type_name = str(attr["annotation"] or attr["type_comment"] or None)
                params.append(
                    Parameter(
                        name=attr["target"].strip(),
                        inferred_type_name=type_name.strip(),
                        default=str(attr["value"]).strip(),
                        help=str(attr["help"] or "").strip(),
                    )
                )

        return params


class RTranslator(Translator):
    @classmethod
    def translate_none(cls, val):
        return 'NULL'

    @classmethod
    def translate_bool(cls, val):
        return 'TRUE' if val else 'FALSE'

    @classmethod
    def translate_dict(cls, val):
        escaped = ', '.join(
            ['{} = {}'.format(cls.translate_str(k), cls.translate(v)) for k, v in val.items()]
        )
        return 'list({})'.format(escaped)

    @classmethod
    def translate_list(cls, val):
        escaped = ', '.join([cls.translate(v) for v in val])
        return 'list({})'.format(escaped)

    @classmethod
    def comment(cls, cmt_str):
        return '# {}'.format(cmt_str).strip()

    @classmethod
    def assign(cls, name, str_val):
        # Leading '_' aren't legal R variable names -- so we drop them when injecting
        while name.startswith("_"):
            name = name[1:]
        return '{} = {}'.format(name, str_val)


class ScalaTranslator(Translator):
    @classmethod
    def translate_int(cls, val):
        strval = cls.translate_raw_str(val)
        return strval + "L" if (val > 2147483647 or val < -2147483648) else strval

    @classmethod
    def translate_dict(cls, val):
        """Translate dicts to scala Maps"""
        escaped = ', '.join(
            ["{} -> {}".format(cls.translate_str(k), cls.translate(v)) for k, v in val.items()]
        )
        return 'Map({})'.format(escaped)

    @classmethod
    def translate_list(cls, val):
        """Translate list to scala Seq"""
        escaped = ', '.join([cls.translate(v) for v in val])
        return 'Seq({})'.format(escaped)

    @classmethod
    def comment(cls, cmt_str):
        return '// {}'.format(cmt_str).strip()

    @classmethod
    def assign(cls, name, str_val):
        return 'val {} = {}'.format(name, str_val)


class JuliaTranslator(Translator):
    @classmethod
    def translate_none(cls, val):
        return 'nothing'

    @classmethod
    def translate_dict(cls, val):
        escaped = ', '.join(
            ["{} => {}".format(cls.translate_str(k), cls.translate(v)) for k, v in val.items()]
        )
        return 'Dict({})'.format(escaped)

    @classmethod
    def translate_list(cls, val):
        escaped = ', '.join([cls.translate(v) for v in val])
        return '[{}]'.format(escaped)

    @classmethod
    def comment(cls, cmt_str):
        return '# {}'.format(cmt_str).strip()


class MatlabTranslator(Translator):
    @classmethod
    def translate_escaped_str(cls, str_val):
        """Translate a string to an escaped Matlab string"""
        if isinstance(str_val, str):
            str_val = str_val.encode('unicode_escape')
            if sys.version_info >= (3, 0):
                str_val = str_val.decode('utf-8')
            str_val = str_val.replace('"', '""')
        return '"{}"'.format(str_val)

    @staticmethod
    def __translate_char_array(str_val):
        """Translates a string to a Matlab char array"""
        if isinstance(str_val, str):
            str_val = str_val.encode('unicode_escape')
            if sys.version_info >= (3, 0):
                str_val = str_val.decode('utf-8')
            str_val = str_val.replace('\'', '\'\'')
        return '\'{}\''.format(str_val)

    @classmethod
    def translate_none(cls, val):
        return 'NaN'

    @classmethod
    def translate_dict(cls, val):
        keys = ', '.join(["{}".format(cls.__translate_char_array(k)) for k, v in val.items()])
        vals = ', '.join(["{}".format(cls.translate(v)) for k, v in val.items()])
        return 'containers.Map({{{}}}, {{{}}})'.format(keys, vals)

    @classmethod
    def translate_list(cls, val):
        escaped = ', '.join([cls.translate(v) for v in val])
        return '{{{}}}'.format(escaped)

    @classmethod
    def comment(cls, cmt_str):
        return '% {}'.format(cmt_str).strip()

    @classmethod
    def codify(cls, parameters, comment='Parameters'):
        content = '{}\n'.format(cls.comment(comment))
        for name, val in parameters.items():
            content += '{};\n'.format(cls.assign(name, cls.translate(val)))
        return content


class CSharpTranslator(Translator):
    @classmethod
    def translate_none(cls, val):
        # Can't figure out how to do this as nullable
        raise NotImplementedError("Option type not implemented for C#.")

    @classmethod
    def translate_bool(cls, val):
        return 'true' if val else 'false'

    @classmethod
    def translate_int(cls, val):
        strval = cls.translate_raw_str(val)
        return strval + "L" if (val > 2147483647 or val < -2147483648) else strval

    @classmethod
    def translate_dict(cls, val):
        """Translate dicts to nontyped dictionary"""

        kvps = ', '.join(
            ["{{ {} , {} }}".format(cls.translate_str(k), cls.translate(v)) for k, v in val.items()]
        )
        return 'new Dictionary<string,Object>{{ {} }}'.format(kvps)

    @classmethod
    def translate_list(cls, val):
        """Translate list to array"""
        escaped = ', '.join([cls.translate(v) for v in val])
        return 'new [] {{ {} }}'.format(escaped)

    @classmethod
    def comment(cls, cmt_str):
        return '// {}'.format(cmt_str).strip()

    @classmethod
    def assign(cls, name, str_val):
        return 'var {} = {};'.format(name, str_val)


class FSharpTranslator(Translator):
    @classmethod
    def translate_none(cls, val):
        return 'None'

    @classmethod
    def translate_bool(cls, val):
        return 'true' if val else 'false'

    @classmethod
    def translate_int(cls, val):
        strval = cls.translate_raw_str(val)
        return strval + "L" if (val > 2147483647 or val < -2147483648) else strval

    @classmethod
    def translate_dict(cls, val):
        tuples = '; '.join(
            [