#!/usr/bin/env python3
import argparse
import json
import os
import sys
from functools import reduce
from typing import Any, List, Set

import yaml
from tools.lite_interpreter.gen_selected_mobile_ops_header import (
    write_selected_mobile_ops,
)
from torchgen.selective_build.selector import (
    combine_selective_builders,
    SelectiveBuilder,
)


def extract_all_operators(selective_builder: SelectiveBuilder) -> Set[str]:
    ops = []
    for op_name, op in selective_builder.operators.items():
        ops.append(op_name)
    return set(ops)


def extract_training_operators(selective_builder: SelectiveBuilder) -> Set[str]:
    ops = []
    for op_name, op in selective_builder.operators.items():
        if op.is_used_for_training:
            ops.append(op_name)
    return set(ops)


def throw_if_any_op_includes_overloads(selective_builder: SelectiveBuilder) -> None:
    ops = []
    for op_name, op in selective_builder.operators.items():
        if op.include_all_overloads:
            ops.append(op_name)
    if ops:
        raise Exception(
            (
                "Operators that include all overloads are "
                + "not allowed since --allow-include-all-overloads "
                + "was specified: {}"
            ).format(", ".join(ops))
        )


def gen_supported_mobile_models(model_dicts: List[Any], output_dir: str) -> None:
    supported_mobile_models_source = """/*
 * Generated by gen_oplist.py
 */
#include "fb/supported_mobile_models/SupportedMobileModels.h"


struct SupportedMobileModelCheckerRegistry {{
  SupportedMobileModelCheckerRegistry() {{
    auto& ref = facebook::pytorch::supported_model::SupportedMobileModelChecker::singleton();
    ref.set_supported_md5_hashes(std::unordered_set<std::string>{{
      {supported_hashes_template}
    }});
  }}
}};

// This is a global object, initializing which causes the registration to happen.
SupportedMobileModelCheckerRegistry register_model_versions;


"""

    # Generate SupportedMobileModelsRegistration.cpp
    md5_hashes = set()
    for model_dict in model_dicts:
        if "debug_info" in model_dict:
            debug_info = json.loads(model_dict["debug_info"][0])
            if debug_info["is_new_style_rule"]:
                for asset, asset_info in debug_info["asset_info"].items():
                    md5_hashes.update(asset_info["md5_hash"])

    supported_hashes = ""
    for md5 in md5_hashes:
        supported_hashes += '"{}",\n'.format(md5)
    with open(
        os.path.join(output_dir, "SupportedMobileModelsRegistration.cpp"), "wb"
    ) as out_file:
        source = supported_mobile_models_source.format(
            supported_hashes_template=supported_hashes
        )
        out_file.write(source.encode("utf-8"))


def main(argv: List[Any]) -> None:
    """This binary generates 3 files:

    1. selected_mobile_ops.h: Primary operators used by templated selective build and Kernel Function
       dtypes captured by tracing
    2. selected_operators.yaml: Selected root and non-root operators (either via tracing or static analysis)
    """
    parser = argparse.ArgumentParser(description="Generate operator lists")
    parser.add_argument(
        "--output-dir",
        "--output_dir",
        help=(
            "The directory to store the output yaml files (selected_mobile_ops.h, "
            + "selected_kernel_dtypes.h, selected_operators.yaml)"
        ),
        required=True,
    )
    parser.add_argument(
        "--model-file-list-path",
        "--model_file_list_path",
        help=(
            "Path to a file that contains the locations of individual "
            + "model YAML files that contain the set of used operators. This "
            + "file path must have a leading @-symbol, which will be stripped "
            + "out before processing."
        ),
        required=True,
    )
    parser.add_argument(
        "--allow-include-all-overloads",
        "--allow_include_all_overloads",
        help=(
            "Flag to allow operators that include all overloads. "
            + "If not set, operators registered without using the traced style will"
            + "break the build."
        ),
        action="store_true",
        default=False,
        required=False,
    )
    options = parser.parse_args(argv)

    if os.path.isfile(options.model_file_list_path):
        print("Processing model file: ", options.model_file_list_path)
        model_dicts = []
        model_dict = yaml.safe_load(open(options.model_file_list_path))
        model_dicts.append(model_dict)
    else:
        print("Processing model directory: ", options.model_file_list_path)
        assert options.model_file_list_path[0] == "@"
        model_file_list_path = options.model_file_list_path[1:]

        model_dicts = []
        with open(model_file_list_path) as model_list_file:
            model_file_names = model_list_file.read().split()
            for model_file_name in model_file_names:
                with open(model_file_name, "rb") as model_file:
                    model_dict = yaml.safe_load(model_file)
                    model_dicts.append(model_dict)

    selective_builders = [SelectiveBuilder.from_yaml_dict(m) for m in model_dicts]

    # While we have the model_dicts generate the supported mobile models api
    gen_supported_mobile_models(model_dicts, options.output_dir)

    # We may have 0 selective builders since there may not be any viable
    # pt_operator_library rule marked as a dep for the pt_operator_registry rule.
    # This is potentially an error, and we should probably raise an assertion
    # failure here. However, this needs to be investigated further.
    selective_builder = SelectiveBuilder.from_yaml_dict({})
    if len(selective_builders) > 0:
        selective_builder = reduce(
            combine_selective_builders,
            selective_builders,
        )

    if not options.allow_include_all_overloads:
        throw_if_any_op_includes_overloads(selective_builder)
    with open(
        os.path.join(options.output_dir, "selected_operators.yaml"), "wb"
    ) as out_file:
        out_file.write(
            yaml.safe_dump(
                selective_builder.to_dict(), default_flow_style=False
            ).encode("utf-8"),
        )

    write_selected_mobile_ops(
        os.path.join(options.output_dir, "selected_mobile_ops.h"),
        selective_builder,
    )


if __name__ == "__main__":
    main(sys.argv[1:])
