#!/usr/bin/env python3
# -*- coding: utf-8 -*-
#
# Copyright 2020 The SkyWater PDK Authors.
#
# Use of this source code is governed by the Apache 2.0
# license that can be found in the LICENSE file or at
# https://www.apache.org/licenses/LICENSE-2.0
#
# SPDX-License-Identifier: Apache-2.0

import os

from dataclasses import dataclass
from enum import Enum
from typing import Optional


def parse_filename(pathname):
    """Extract library and module name from pathname.

    >>> t = list(parse_filename('sky130_fd_io-top_ground_padonlyv2-tt_1p80V_3p30V_3p30V_25C.wrap.lib'))
    >>> t.pop(0)
    Cell(name='top_ground_padonlyv2', library=Library(node=LibraryNode.SKY130, source=LibrarySource('fd'), type=LibraryType.io, name=None))
    >>> t.pop(0)
    'tt_1p80V_3p30V_3p30V_25C'
    >>> t.pop(0)
    'wrap.lib'

    """
    dirname, filename = os.path.split(pathname)

    if '.' in filename:
        basename, extension = filename.split('.', 1)
    else:
        basename = filename
        extension = ''
    basename = basename.replace('-', SEPERATOR)

    library, cell, extra = basename.split(SEPERATOR, 3)
    return (Cell.parse(library+SEPERATOR+cell), extra, extension)


SEPERATOR = "__"


class LibraryNode(Enum):
    SKY130 = "SkyWater 130nm"

    @classmethod
    def parse(cls, s):
        s = s.upper()
        if not hasattr(cls, s):
            raise ValueError("Unknown node: {}".format(s))
        return getattr(cls, s)

    def __repr__(self):
        return "LibraryNode."+self.name


class LibrarySource(str):
    """Where a library was created."""
    Known = []

    @classmethod
    def parse(cls, s):
        try:
            return cls.Known[cls.Known.index(s)]
        except ValueError:
            return cls(s)

    @property
    def fullname(self):
        if self in self.Known:
            return self.__doc__
        else:
            return 'Unknown source: '+str.__repr__(self)

    def __repr__(self):
        return 'LibrarySource({})'.format(str.__repr__(self))


Foundary = LibrarySource("fd")
Foundary.__doc__ = "The SkyWater Foundary"
LibrarySource.Known.append(Foundary)

Efabless = LibrarySource("ef")
Efabless.__doc__ = "Efabless"
LibrarySource.Known.append(Efabless)

OSU = LibrarySource("osu")
OSU.__doc__ = "Oklahoma State University"
LibrarySource.Known.append(OSU)


class LibraryType(Enum):
    pr = "Primitives"
    sc = "Standard Cells"
    sp = "Build Space (Flash, SRAM, etc)"
    io = "IO and Periphery"
    xx = "Miscellaneous"

    @classmethod
    def parse(cls, s):
        if not hasattr(cls, s):
            raise ValueError("Unknown library type: {}".format(s))
        return getattr(cls, s)

    def __repr__(self):
        return "LibraryType."+self.name

    def __str__(self):
        return self.value


@dataclass
class Library:
    """

    >>> l = Library.parse("sky130_fd_sc_hd")
    >>> l
    Library(node=LibraryNode.SKY130, source=LibrarySource('fd'), type=LibraryType.sc, name='hd')
    >>> l.fullname
    'sky130_fd_sc_hd'
    >>> l.source.fullname
    'The SkyWater Foundary'
    >>> print(l.type)
    Standard Cells

    >>> l = Library.parse("sky130_rrr_sc_hd")
    >>> l
    Library(node=LibraryNode.SKY130, source=LibrarySource('rrr'), type=LibraryType.sc, name='hd')
    >>> l.fullname
    'sky130_rrr_sc_hd'
    >>> l.source.fullname
    "Unknown source: 'rrr'"


    """

    node: LibraryNode
    source: LibrarySource
    type: LibraryType
    name: Optional[str] = None

    @property
    def fullname(self):
        output = []
        output.append(self.node.name.lower())
        output.append(self.source.lower())
        output.append(self.type.name)
        if self.name:
            output.append(self.name)
        return "_".join(output)

    @classmethod
    def parse(cls, s):
        if SEPERATOR in s:
            raise ValueError(
                "Found separator '__' in library name: {!r}".format(s))

        bits = s.split("_")
        if len(bits) < 3:
            raise ValueError(
                "Did not find enough parts in library name: {}".format(bits))

        kw = {}
        kw['node'] = LibraryNode.parse(bits.pop(0))
        kw['source'] = LibrarySource.parse(bits.pop(0))
        kw['type'] = LibraryType.parse(bits.pop(0))
        if bits:
            kw['name'] = bits.pop(0)
        return cls(**kw)


@dataclass
class Cell:
    """
    >>> c = Cell.parse("sky130_fd_sc_hd__abc")
    >>> c
    Cell(name='abc', library=Library(node=LibraryNode.SKY130, source=LibrarySource('fd'), type=LibraryType.sc, name='hd'))
    >>> c.fullname
    'sky130_fd_sc_hd__abc'

    >>> c = Cell.parse("abc")
    >>> c
    Cell(name='abc', library=None)
    >>> c.fullname
    Traceback (most recent call last):
        ...
    ValueError: Can't get fullname for cell without a library! Cell(name='abc', library=None)
    """

    name: str
    library: Optional[Library] = None

    @property
    def fullname(self):
        if not self.library:
            raise ValueError(
                "Can't get fullname for cell without a library! {}".format(
                    self))
        return "{}__{}".format(self.library.fullname, self.name)

    @classmethod
    def parse(cls, s):
        kw = {}
        if SEPERATOR in s:
            library, s = s.split(SEPERATOR, 1)
            kw['library'] = Library.parse(library)
        kw['name'] = s
        return cls(**kw)


if __name__ == "__main__":
    import doctest
    doctest.testmod()