# Copyright (c) 2019-2022 Manfred Moitzi
# License: MIT License
from typing import TYPE_CHECKING
from ezdxf.lldxf import validator
from ezdxf.lldxf.attributes import (
    DXFAttr,
    DXFAttributes,
    DefSubclass,
    XType,
    RETURN_DEFAULT,
    group_code_mapping,
    merge_group_code_mappings,
)
from ezdxf.lldxf.const import (
    SUBCLASS_MARKER,
    DXF12,
    MODEL_SPACE_R12,
    PAPER_SPACE_R12,
    MODEL_SPACE_R2000,
    PAPER_SPACE_R2000,
)
from ezdxf.math import NULLVEC
from .dxfentity import base_class, SubclassProcessor, DXFEntity
from .factory import register_entity

if TYPE_CHECKING:
    from ezdxf.eztypes import TagWriter, DXFNamespace

__all__ = ["Block", "EndBlk"]

acdb_entity = DefSubclass(
    "AcDbEntity",
    {
        # No auto fix for invalid layer names!
        "layer": DXFAttr(
            8, default="0", validator=validator.is_valid_layer_name
        ),
        "paperspace": DXFAttr(
            67,
            default=0,
            optional=True,
            validator=validator.is_integer_bool,
            fixer=RETURN_DEFAULT,
        ),
    },
)
acdb_entity_group_codes = group_code_mapping(acdb_entity)

acdb_block_begin = DefSubclass(
    "AcDbBlockBegin",
    {
        "name": DXFAttr(2, validator=validator.is_valid_block_name),
        # The 2nd name with group code 3 is handled internally, and is not an
        # explicit DXF attribute.
        "description": DXFAttr(4, default="", optional=True),
        # Flags:
        # 0 = Indicates none of the following flags apply
        # 1 = This is an anonymous block generated by hatching, associative
        #     dimensioning, other internal operations, or an application
        # 2 = This block has non-constant attribute definitions (this bit is not set
        #     if the block has any attribute definitions that are constant, or has
        #     no attribute definitions at all)
        # 4 = This block is an external reference (xref)
        # 8 = This block is an xref overlay
        # 16 = This block is externally dependent
        # 32 = This is a resolved external reference, or dependent of an external
        #      reference (ignored on input)
        # 64 = This definition is a referenced external reference (ignored on input)
        "flags": DXFAttr(70, default=0),
        "base_point": DXFAttr(10, xtype=XType.any_point, default=NULLVEC),
        "xref_path": DXFAttr(1, default=""),
    },
)
acdb_block_begin_group_codes = group_code_mapping(acdb_block_begin)
merged_block_begin_group_codes = merge_group_code_mappings(
    acdb_entity_group_codes, acdb_block_begin_group_codes
)

MODEL_SPACE_R2000_LOWER = MODEL_SPACE_R2000.lower()
MODEL_SPACE_R12_LOWER = MODEL_SPACE_R12.lower()
PAPER_SPACE_R2000_LOWER = PAPER_SPACE_R2000.lower()
PAPER_SPACE_R12_LOWER = PAPER_SPACE_R12.lower()


@register_entity
class Block(DXFEntity):
    """DXF BLOCK entity"""

    DXFTYPE = "BLOCK"
    DXFATTRIBS = DXFAttributes(base_class, acdb_entity, acdb_block_begin)

    # Block entity flags:
    # This is an anonymous block generated by hatching, associative
    # dimensioning, other internal operations, or an application:
    ANONYMOUS = 1

    # This block has non-constant attribute definitions (this bit is not set
    # if the block has any attribute definitions that are constant, or has no
    # attribute definitions at all):
    NON_CONSTANT_ATTRIBUTES = 2

    # This block is an external reference:
    XREF = 4

    # This block is an xref overlay:
    XREF_OVERLAY = 8

    # This block is externally dependent:
    EXTERNAL = 16

    # This is a resolved external reference, or dependent of an external reference:
    RESOLVED = 32

    # This definition is a referenced external reference:
    REFERENCED = 64

    def load_dxf_attribs(
        self, processor: SubclassProcessor = None
    ) -> "DXFNamespace":
        """Loading interface. (internal API)"""
        dxf = super().load_dxf_attribs(processor)
        if processor is None:
            return dxf
        processor.simple_dxfattribs_loader(dxf, merged_block_begin_group_codes)
        if processor.r12:
            name = dxf.name.lower()
            if name == MODEL_SPACE_R12_LOWER:
                dxf.name = MODEL_SPACE_R2000
            elif name == PAPER_SPACE_R12_LOWER:
                dxf.name = PAPER_SPACE_R2000
        return dxf

    def export_entity(self, tagwriter: "TagWriter") -> None:
        """Export entity specific data as DXF tags."""
        super().export_entity(tagwriter)

        if tagwriter.dxfversion > DXF12:
            tagwriter.write_tag2(SUBCLASS_MARKER, acdb_entity.name)
        if self.dxf.hasattr("paperspace"):
            tagwriter.write_tag2(67, 1)
        self.dxf.export_dxf_attribs(tagwriter, "layer")
        if tagwriter.dxfversion > DXF12:
            tagwriter.write_tag2(SUBCLASS_MARKER, acdb_block_begin.name)

        name = self.dxf.name
        if tagwriter.dxfversion == DXF12:
            # export modelspace and paperspace with leading '$' instead of '*'
            if name.lower() == MODEL_SPACE_R2000_LOWER:
                name = MODEL_SPACE_R12
            elif name.lower() == PAPER_SPACE_R2000_LOWER:
                name = PAPER_SPACE_R12

        tagwriter.write_tag2(2, name)
        self.dxf.export_dxf_attribs(tagwriter, ["flags", "base_point"])
        tagwriter.write_tag2(3, name)
        self.dxf.export_dxf_attribs(tagwriter, ["xref_path", "description"])

    @property
    def is_layout_block(self) -> bool:
        """Returns ``True`` if this is a :class:`~ezdxf.layouts.Modelspace` or
        :class:`~ezdxf.layouts.Paperspace` block definition.
        """
        name = self.dxf.name.lower()
        return name.startswith("*model_space") or name.startswith(
            "*paper_space"
        )

    @property
    def is_anonymous(self) -> bool:
        """Returns ``True`` if this is an anonymous block generated by
        hatching, associative dimensioning, other internal operations, or an
        application.

        """
        return self.get_flag_state(Block.ANONYMOUS)

    @property
    def is_xref(self) -> bool:
        """Returns ``True`` if bock is an external referenced file."""
        return self.get_flag_state(Block.XREF)

    @property
    def is_xref_overlay(self) -> bool:
        """Returns ``True`` if bock is an external referenced overlay file."""
        return self.get_flag_state(Block.XREF_OVERLAY)


acdb_block_end = DefSubclass("AcDbBlockEnd", {})


@register_entity
class EndBlk(DXFEntity):
    """DXF ENDBLK entity"""

    DXFTYPE = "ENDBLK"
    DXFATTRIBS = DXFAttributes(base_class, acdb_entity, acdb_block_end)

    def load_dxf_attribs(
        self, processor: SubclassProcessor = None
    ) -> "DXFNamespace":
        """Loading interface. (internal API)"""
        dxf = super().load_dxf_attribs(processor)
        if processor:
            processor.simple_dxfattribs_loader(dxf, acdb_entity_group_codes)  # type: ignore
        return dxf

    def export_entity(self, tagwriter: "TagWriter") -> None:
        """Export entity specific data as DXF tags."""
        super().export_entity(tagwriter)

        if tagwriter.dxfversion > DXF12:
            tagwriter.write_tag2(SUBCLASS_MARKER, acdb_entity.name)
        if self.dxf.hasattr("paperspace"):
            tagwriter.write_tag2(67, 1)
        self.dxf.export_dxf_attribs(tagwriter, "layer")
        if tagwriter.dxfversion > DXF12:
            tagwriter.write_tag2(SUBCLASS_MARKER, acdb_block_end.name)
