# See LICENSE for licensing information.
#
# Copyright (c) 2016-2021 Regents of the University of California and The Board
# of Regents for the Oklahoma Agricultural and Mechanical College
# (acting for and on behalf of Oklahoma State University)
# All rights reserved.
#

from openram.base import design
from openram.base import vector
from openram import OPTS
from openram.sram_factory import factory
from openram.tech import drc

class rom_poly_tap(design):

    def __init__(self, name="", cell_name=None, tx_type="nmos", strap_layer="m2", add_tap=False):
        super().__init__(name, cell_name)
        self.strap_layer=strap_layer
        self.tx_type = tx_type
        self.add_tap = add_tap
        self.pitch_offset = 0
        self.create_netlist()
        self.create_layout()

    def create_netlist(self):
        #for layout constants
        if self.tx_type == "nmos":
            self.dummy = factory.create(module_type="rom_base_cell")
        else:
            self.dummy = factory.create(module_type="rom_precharge_cell")

        self.pmos = factory.create(module_type="ptx", tx_type="pmos")

    def create_layout(self):

        self.place_via()

        if self.add_tap:
            self.place_active_tap()
            self.extend_poly()
        self.add_boundary()

        # if self.length != 0:
        #     self.place_strap()

    
    def add_boundary(self):
        contact_width = self.poly_contact.width 

        # offset = self.active_space - (contact_width - self.active_enclose_contact - self.active_extend_contact)
        self.height = self.dummy.height
        self.width = contact_width + self.pitch_offset 

        super().add_boundary()

    def place_via(self):
        
        contact_width = self.poly_contact.width

        # DRC rule here is hard coded since licon.9 isnt included in skywater130 tech file

        # poly contact spacing to P-diffusion < 0.235um (licon.9 + psdm.5a)
        if OPTS.tech_name == "sky130":
            self.contact_x_offset =  0.235 - (contact_width - self.pmos.contact_width) * 0.5 - self.poly_extend_active
        else:
            assert(False)

        contact_y = self.dummy.cell_inst.width * 0.5 - 0.5 * self.contact_width - self.active_enclose_contact

        if self.tx_type == "nmos":
            
            # contact_y = self.dummy.cell_inst.width * 0.5 - 0.5 * self.contact_width - self.active_enclose_contact
            # contact_y = self.dummy.poly.offset.x + (self.poly_width * 0.5)
            self.contact_x_offset = 0
        # else:
        #     contact_y = self.pmos.poly_positions[0].x - self.pmos.active_offset.x

        contact_x = contact_width * 0.5 + self.contact_x_offset
        self.contact_offset = vector(contact_x, contact_y)

        self.via = self.add_via_stack_center(from_layer="poly",
                                  to_layer=self.strap_layer,
                                  offset=self.contact_offset)
        self.add_layout_pin_rect_center("poly_tap", self.strap_layer, self.contact_offset)


    # def place_strap(self):

    #     strap_start = vector(self.via.lx() , self.via.cy())

    #     strap_end = vector( self.dummy.width * (self.length + 1), self.via.cy())

    #     self.strap = self.add_path(self.strap_layer, (strap_start, strap_end))

    def extend_poly(self):
    
        self.add_segment_center("poly", self.via.center(), vector(self.via.cx() + self.pitch_offset, self.via.cy()))
        self.add_segment_center("poly", self.via.center(), vector(0, self.via.cy()))


        
    def place_active_tap(self):
        gap = self.poly_extend_active - 0.5 * ( self.active_contact.height - self.poly_contact.width )
        offset = self.active_space - gap
        # tap_x = self.via.cx() + self.contact_width + self.active_enclose_contact + self.poly_enclose_contact
        tap_x = self.via.cx() + offset
        tap_y = self.via.cy() + self.dummy.width * 0.5 
        contact_pos = vector(tap_x, tap_y)
        

        # edge of the next nmos
        active_edge = self.dummy.width - self.dummy.cell_inst.height - self.poly_extend_active
        
        # edge of the active contact
        tap_edge = tap_x + 0.5 * self.active_contact.height
        self.pitch_offset += (self.active_space * 2) - (tap_edge - active_edge) + self.contact_x_offset
        
        if self.tx_type == "nmos":

            self.add_via_center(layers=self.active_stack,
                                offset=contact_pos,
                                implant_type="p",
                                well_type="p",
                                directions="nonpref")
            self.add_power_pin(name="gnd", 
                            loc=contact_pos,
                            start_layer=self.active_stack[2])
            self.add_layout_pin_rect_center("active_tap", self.supply_stack[0], contact_pos)