#!/usr/bin/env python3
# -*- coding: utf-8 -*-
#
# Copyright (C) 2017-2020  The Project X-Ray Authors.
#
# Use of this source code is governed by a ISC-style
# license that can be found in the LICENSE file or at
# https://opensource.org/licenses/ISC
#
# SPDX-License-Identifier: ISC
"""
This script generates code snippets for cell definition, technology mapping and
VPR architecture definition. It reads correlation of IOB fasm features with
IO standard settings such as IOSTANDARD, DRIVE and SLEW and generates:

- Verilog model parameter definitions that match fasm features.
- Xilinx's IOB parameter translation to those features.
- Assignment of model parameters to the actual fasm features for VPR arch def.

Generated code snippets need to be manually copied to relevant places in the
target code / arch. def.
"""
import os
import argparse
import csv

from collections import namedtuple

IOSettings = namedtuple("IOSettings", "iostandard, drive, slew, is_diff")

# =============================================================================


def load_feature_data(fname):
    """
    Load feature vs. IO settings correlation data from a CSV file.
    """

    # Load the data from CSV
    feature_data = {}
    with open(fname, "r") as fp:
        for line in csv.DictReader(fp):

            # Get IOSettings
            ios_parts = line["iosettings"].split(".")
            ios = IOSettings(
                ios_parts[0],
                int(ios_parts[1][1:]) if ios_parts[1][1:] != "_FIXED" else
                None, ios_parts[2], "DIFF_" in ios_parts[0])

            # Feature activity
            feature_data[ios] = {k: line[k] for k in list(line.keys())[1:]}

    return feature_data


def filter_feature_data(feature_data):
    """
    Filters fasm features and leaves only those related to IO settings.
    """

    for data in feature_data.values():
        for feature in dict(data):

            if "DISABLE" in feature:
                del data[feature]
            if "PULLTYPE" in feature:
                del data[feature]
            if "IN_TERM" in feature:
                del data[feature]
            if "LOW_PWR" in feature:
                del data[feature]

    return feature_data


def get_relevant_parameters(feature_data, iob_type):
    """
    Gets features relevant to a specific IOB type and assign them verilog
    parameter names.
    """

    # Get all features and make parameter names
    all_features = set(
        [f for data in feature_data.values() for f in data.keys()])
    parameters = []

    # Check if a feature is relevant to particular IOB type
    is_diff = "DIFF_" in iob_type

    for feature in all_features:
        for iosettings in feature_data:
            if iosettings.is_diff == is_diff:
                base_iob_type = iob_type.replace("DIFF_", "")
                if base_iob_type in feature_data[iosettings][feature]:
                    parameters.append((
                        feature,
                        feature.replace(".", "_"),
                    ))
                    break

    return parameters


# =============================================================================


def generate_parameter_defs(parameters):
    """
    Generates verilog parameter definitions for the IOB cell model.
    """
    verilog = []

    for feature, parameter in sorted(parameters):
        verilog.append("parameter [0:0] {} = 1'b0;".format(parameter))

    return "\n".join(verilog)


def generate_parameter_map(parameters):
    """
    Generates mapping of parameters for fasm features for architecture
    definition.
    """
    xml = []

    xml.append("<meta name=\"fasm_params\">")
    for feature, parameter in sorted(parameters):
        xml.append("  {} = {}".format(feature, parameter))
    xml.append("</meta>")

    return "\n".join(xml)


def generate_parameter_assignments(parameters, feature_data, iob_type):
    """
    Generates parameter assignmets to be used inside the techmap. For
    each IOB cell parameter a set of conditions is generated based on
    feature activity observation.
    """
    verilog = []

    is_diff = "DIFF_" in iob_type
    base_iob_type = iob_type.replace("DIFF_", "")

    for feature, parameter in sorted(parameters):
        condition = []
        for iosettings in feature_data:

            if iosettings.is_diff != is_diff:
                continue

            # Feature is set
            if base_iob_type in feature_data[iosettings][feature]:
                cond = "IOSTANDARD == \"{}\"".format(
                    iosettings.iostandard.upper())

                if base_iob_type in ["O", "T"]:
                    if iosettings.drive is not None and "DRIVE" in feature:
                        cond += " && DRIVE == {}".format(iosettings.drive)
                    if "SLEW" in feature:
                        cond += " && SLEW == \"{}\"".format(iosettings.slew)

                condition.append(cond)

        condition = sorted(list(set(condition)))

        condition_str = " || \n".join(["  ({})".format(c) for c in condition])
        verilog.append(".{}(\n{}\n)".format(parameter, condition_str))

    return ",\n".join(verilog)


# =============================================================================


def run():
    """
    Main.
    """

    # Parse arguments
    parser = argparse.ArgumentParser()
    parser.add_argument("features", type=str, help="Input CSV file")

    args = parser.parse_args()

    # Load iosettings vs. feature map
    feature_data = load_feature_data(args.features)
    # Reject non-iostandard related features
    feature_data = filter_feature_data(feature_data)

    # Make parameters
    parameters = {}
    for iob_type in ["I", "O", "T", "DIFF_I", "DIFF_O", "DIFF_T"]:
        parameters[iob_type] = get_relevant_parameters(feature_data, iob_type)

    # Parameter definition
    with open("cells_sim.v", "w") as fp:
        for iob_type, params in parameters.items():
            fp.write("// {} {}\n\n".format(iob_type, "=" * 70))
            verilog = generate_parameter_defs(params)
            fp.write(verilog + "\n\n")

    # Parameter assignments
    with open("cells_map.v", "w") as fp:
        for iob_type, params in parameters.items():
            fp.write("// {} {}\n\n".format(iob_type, "=" * 70))
            verilog = generate_parameter_assignments(
                params, feature_data, iob_type)
            fp.write(verilog + "\n\n")

    # Parameter assignments
    with open("arch.xml", "w") as fp:
        for iob_type, params in parameters.items():
            fp.write("<!-- {} -->\n\n".format(iob_type))
            xml = generate_parameter_map(params)
            fp.write(xml + "\n\n")


if __name__ == "__main__":
    run()