from . import *
from enum import Enum

class errors(Enum):
    UNEXPECTED_EOF   = "unexpected EOF"
    EXPECTED_HEADER  = "expected file header"    
    EXPECTED_BGNLIB  = "expected beginning of library"
    EXPECTED_LIBNAME = "Library name is missing"
    EXPECTED_ENDMASK = "MASK records was not terminated by ENDMASK"
    EXPECTED_STRNAME = "encountered nameless structure"
    EXPECTED_UNITS   = "no unit record in file"
    EXPECTED_LAYER   = "expected a layer record in element"
    EXPECTED_POINTS  = "expected coordinates for element"
    EXPECTED_POINT   = "expected coordinate for element"
    EXPECTED_DATATYPE = "expected datatype"
    EXPECTED_ENDEL   = "end of element is missing"
    EXPECTED_TEXTTYPE = "expected TEXTTYPE"
    EXPECTED_STRING   = "textelement is missing text"
    EXPECTED_BOXTYPE  = "expected BOXTYPE"
    EXPECTED_SNAME    = "expected SNAME"
    EXPECTED_COLROW   = "expected COLROW"
    AREF_MISSING_POINTS = "aref needs three points"
    INVALID_PATHTYPE = "pathtype must be in range [0,2]"

class Warnings(Enum):
    EXPECTED_ENDLIB  = "missing end of library"
    
class ParserError(Exception):
    pass

class Parser(Reader):
    def __init__(self, file, progress_callback=None):
        super(Parser, self).__init__(file)
        
        self._token = None
        self.progress_callback = progress_callback
        
        # parser state
        self.Library = Library()
        self.current_structure = None
    
    @property
    def token(self):
        return self._token
    
    @token.setter
    def token(self, t):
        self._token = t

    def next_token(self, throw=False):
        self.token = self.read_record()

        if not self.token and throw:
            raise ParserError(errors.UNEXPECTED_EOF)

        # if self.token:
        #     print(self.token.ident.name)

        return self.token

    def parse_lib(self):
        # read header  
        if not self.next_token() or self.token.ident != Records.HEADER:
            raise ParserError(errors.EXPECTED_HEADER)
        
        self.Library.version = self.read_short()

        # must see BGNLIB
        if not self.next_token() or self.token.ident != Records.BGNLIB:
            raise ParserError(errors.EXPECTED_BGNLIB)
        
        self.Library.last_mod    = self.read_date()
        self.Library.last_access = self.read_date()

        if not self.next_token() or self.token.ident != Records.LIBNAME:
            raise ParserError(errors.EXPECTED_LIBNAME)

        self.Library.name = self.read_ascii(self.token.len)

        # read optional records
        while self.next_token():
            if self.token.ident  == Records.REFLIBS or    \
                self.token.ident == Records.FONTS or     \
                self.token.ident == Records.ATTRTABLE or \
                self.token.ident == Records.GENERATIONS:
                # skip these records
                self.skip(self.token.len)

            elif self.token.ident == Records.FORMAT:
                self.skip(self.token.len)

                # look for optional mask
                while self.next_token().ident == Records.MASK:
                    self.skip(self.token.len)
                                   
                if self.token.ident != Records.ENDMASK:
                    raise ParserError(errors.EXPECTED_ENDMASK)

            else:
                # continue
                break

        if self.token.ident != Records.UNITS:
            raise ParserError(errors.EXPECTED_UNITS)

        # read units
        self.Library.units_per_dbunit = self.read_double()
        self.Library.meters_per_unit  = self.read_double()
        
        while self.next_token() and self.parse_structure():
            pass
       
        if self.token.ident != Records.ENDLIB:
            print(Warnings.EXPECTED_ENDLIB.value)

        # tell callback that the process completed
        if self.progress_callback:
            self.progress_callback(self)

    def parse_structure(self):
        self.structure = Structure()
        
        if self.token.ident != Records.BGNSTR:
            return False

        self.structure.last_mod = self.read_date()
        self.structure.last_access = self.read_date()

        # read sname
        if not self.next_token() or self.token.ident != Records.STRNAME:
            raise ParserError(errors.EXPECTED_STRNAME)
        
        self.structure.name = self.read_ascii(self.token.len)

        while self.next_token() and self.token.ident != Records.ENDSTR:
            if self.token.ident == Records.BOUNDARY:
                self.parse_boundary()
            elif self.token.ident == Records.PATH:
                self.parse_path()
            elif self.token.ident == Records.TEXT:
                self.parse_text()
            elif self.token.ident == Records.SREF:
                self.parse_sref()
            elif self.token.ident == Records.AREF:
                self.parse_aref()
            else:
                self.skip(self.token.len)
            
            if self.progress_callback:
                self.progress_callback(self)

        self.Library.structures[self.structure.name] = self.structure
        self.structure = None

        return True

    def parse_element(self, element):
        if self.token.ident == Records.ELFLAGS:
            element.elflags = self.read_short()
            self.next_token(True)
        
        if self.token.ident == Records.PLEX:
            element.plex = self.read_int()
            self.next_token(True)

    def parse_layer(self, element):
        if self.token.ident != Records.LAYER:
            raise ParserError(errors.EXPECTED_LAYER)

        element.layer = self.read_ushort()

    def parse_boundary(self):
        element = Boundary()
        self.next_token(True)
        self.parse_element(element)
        self.parse_layer(element)

        if not self.next_token() or self.token.ident != Records.DATATYPE:
            raise ParserError(errors.EXPECTED_DATATYPE)

        element.datatype = self.read_short()

        if not self.next_token() or self.token.ident != Records.XY:
            raise ParserError(errors.EXPECTED_POINTS)

        element.points = self.read_coords(self.token.len)

        if not self.next_token() or self.token.ident != Records.ENDEL:
            raise ParserError(errors.EXPECTED_ENDEL)

        self.structure.elements.append(element)

    def parse_path(self):
        element = Path()
        self.next_token(True)
        self.parse_element(element)
        self.parse_layer(element)

        if not self.next_token() or self.token.ident != Records.DATATYPE:
            raise ParserError(errors.EXPECTED_DATATYPE)
        
        element.datatype = self.read_short()
            
        self.next_token(True)
        
        if self.token.ident == Records.PATHTYPE:
            pathtype = self.read_short()
            if pathtype < 0 or pathtype > 4 or pathtype == 3:  
                raise ParserError(errors.INVALID_PATHTYPE)
            
            element.pathStyle = Path.Styles(pathtype)
            self.next_token(True)
        
        if self.token.ident == Records.WIDTH:
            element.width = self.read_int()
            self.next_token(True)

        if self.token.ident == Records.BGNEXTN:
            element.extendEnd[0] = self.read_int()
            self.next_token(True)
        elif element.pathStyle == Path.Styles.OFFSET_ENDS:
            element.extendEnd[0] = element.width/2

        if self.token.ident == Records.ENDEXTN:
            element.extendEnd[1] = self.read_int()
            self.next_token(True)
        elif element.pathStyle == Path.Styles.OFFSET_ENDS:
            element.extendEnd[1] = element.width/2

        if self.token.ident != Records.XY:
            raise ParserError(errors.EXPECTED_POINTS)

        element.points = self.read_coords(self.token.len)

        if not self.next_token() or self.token.ident != Records.ENDEL:
            raise ParserError(errors.EXPECTED_ENDEL)
    
        self.structure.elements.append(element)

    def parse_text(self):
        element = Text()
        self.next_token(True)
        self.parse_element(element)
        self.parse_layer(element)

        if not self.next_token() or self.token.ident != Records.TEXTTYPE:
            raise ParserError(errors.EXPECTED_TEXTTYPE)

        element.datatype = self.read_short()

        self.next_token(True)

        if self.token.ident == Records.PRESENTATION:
            temp = self.read_short()
            element.fontnumber = (temp>>10)&0x03
            element.verticalJustification   = Text.VJust((temp>>12)&0x03)
            element.horizontalJustification = Text.HJust((temp>>14)&0X03)
            
            self.next_token(True)

        if self.token.ident == Records.PATHTYPE:
            element.pathStype = Path.Styles(self.read_short())
            self.next_token(True)
        
        if self.token.ident == Records.WIDTH:
            element.pathWidth = self.read_short()
            self.next_token(True)

        self.parse_strans(element.transformation)
        
        if self.token.ident != Records.XY:
            raise ParserError(errors.EXPECTED_POINT)

        element.point = self.read_coord()
        
        # skip potential array (if given)
        self.skip(self.token.len - 8)

        if not self.next_token() or self.token.ident != Records.STRING:
            raise ParserError(errors.EXPECTED_STRING)

        element.string = self.read_ascii(self.token.len)

        if not self.next_token() or self.token.ident != Records.ENDEL:
            raise ParserError(errors.EXPECTED_ENDEL)

        self.structure.elements.append(element)
        

    def parse_strans(self, trans:Transformation):
        if self.token.ident != Records.STRANS:
            return

        flags = self.read_ushort()
        if flags & 0x01:
            trans.mirror_x = True

        if flags & 0x2000:
            trans.absolute_magnification = True

        if flags & 0x4000:
            trans.absolute_rotation = True
    
        self.next_token(True) 

        if self.token.ident == Records.MAG:
            trans.zoom = self.read_double()
            self.next_token(True)

        if self.token.ident == Records.ANGLE:
            trans.rotation = self.read_double()
            self.next_token(True)

    def parse_box(self):
        element = Box()
        self.next_token(True)
        self.parse_element(element)
        self.parse_layer(element)

        if not self.next_token() or self.token.ident != Records.BOXTYPE:
            raise ParserError(errors.EXPECTED_BOXTYPE)
        
        element.datatype = self.read_short()

        if not self.next_token() or self.token.ident != Records.XY:
            raise ParserError(errors.EXPECTED_POINTS)

        element.points = self.read_coords(self.token.len)

        if not self.next_token() or self.token.ident != Records.ENDEL:
            raise ParserError(errors.EXPECTED_ENDEL)
        
        self.structure.elements.append(element)
    
    def parse_sref(self):
        element = SRef()
        element.parent = self.structure

        if not self.next_token(): 
            raise ParserError(errors.EXPECTED_SNAME)
        
        self.parse_element(element)

        if self.token.ident != Records.SNAME:
            raise ParserError(errors.EXPECTED_SNAME)
        
        element.structure = self.read_ascii(self.token.len)
        
        self.next_token(True)
        self.parse_strans(element.transformation)

        if self.token.ident != Records.XY:
            raise ParserError(errors.EXPECTED_POINT)

        element.position = self.read_coord()
        self.skip(self.token.len - 8)
        
        if not self.next_token() or self.token.ident != Records.ENDEL:
            raise ParserError(errors.EXPECTED_ENDEL)
        
        self.structure.references.append(element)
    
    def parse_aref(self):
        element = ARef()
        element.parent = self.structure

        if not self.next_token(): 
            raise ParserError(errors.EXPECTED_SNAME)
        
        self.parse_element(element)

        if self.token.ident != Records.SNAME:
            raise ParserError(errors.EXPECTED_SNAME)
        
        element.structure = self.read_ascii(self.token.len)
        
        self.next_token(True)

        self.parse_strans(element.transformation)

        if self.token.ident != Records.COLROW:
            raise ParserError(errors.EXPECTED_COLROW)

        element.size = (self.read_short(), self.read_short())

        if not self.next_token() or self.token.ident != Records.XY:
            raise ParserError(errors.EXPECTED_POINT)

        if self.token.len != 3*8:
            raise ParserError(errors.AREF_MISSING_POINTS)

        element.position = self.read_coord()
        element.bounds[0] = self.read_coord()
        element.bounds[1] = self.read_coord()

        if not self.next_token() or self.token.ident != Records.ENDEL:
            raise ParserError(errors.EXPECTED_ENDEL)
        
        self.structure.references.append(element)

def parse_file(file, progress_func=None):
    parser = Parser(file, progress_callback=progress_func)
    parser.parse_lib()

    return parser.Library