# Copyright (c) 2022 PaddlePaddle Authors. All Rights Reserved.
# 
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
# 
#     http://www.apache.org/licenses/LICENSE-2.0
# 
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

import logging
import yaml
import re
import argparse
import os

########################
### Global Variables ###
########################
ops_to_fill_zero_for_empty_grads = set(
    ["split_grad", "rnn_grad", "matmul_double_grad"])

# For API dispatch used at python-level
# { op_name : [arg_name, ...] }
core_ops_returns_info = {}
core_ops_args_info = {}
core_ops_args_type_info = {}

yaml_types_mapping = {
    'int' : 'int', 'int32_t' : 'int32_t', 'int64_t' : 'int64_t',  'size_t' : 'size_t', \
    'float' : 'float', 'double' : 'double', 'bool' : 'bool', \
    'str' : 'std::string', \
    'Place' : 'paddle::experimental::Place', 'DataLayout' : 'paddle::experimental::DataLayout', 'DataType' : 'paddle::experimental::DataType', \
    'int64_t[]' : 'std::vector<int64_t>', 'int[]' : 'std::vector<int>',
    'Tensor' : 'Tensor',
    'Tensor[]' : 'std::vector<Tensor>',
    'Tensor[Tensor[]]' : 'std::vector<std::vector<Tensor>>',
    'Scalar' : 'paddle::experimental::Scalar',
    'Scalar(int)' : 'paddle::experimental::Scalar',
    'Scalar(int64_t)' : 'paddle::experimental::Scalar',
    'Scalar(float)' : 'paddle::experimental::Scalar',
    'Scalar(double)' : 'paddle::experimental::Scalar',
    'IntArray' : 'paddle::experimental::IntArray'
}


#############################
###  File Reader Helpers  ###
#############################
def AssertMessage(lhs_str, rhs_str):
    return f"lhs: {lhs_str}, rhs: {rhs_str}"


def ReadFwdFile(filepath):
    f = open(filepath, 'r')
    contents = yaml.load(f, Loader=yaml.FullLoader)
    f.close()
    return contents


def ReadBwdFile(filepath):
    f = open(filepath, 'r')
    contents = yaml.load(f, Loader=yaml.FullLoader)
    ret = {}
    for content in contents:
        assert 'backward_api' in content.keys(), AssertMessage('backward_api',
                                                               content.keys())
        if 'backward_api' in content.keys():
            api_name = content['backward_api']

        ret[api_name] = content
    f.close()
    return ret


##################################
###  Generic Helper Functions  ###
##################################
def FindGradName(string):
    return string + "_grad"


def FindForwardName(string):
    if not string.endswith("_grad"):
        return None
    return string[:-5]


def IsGradName(string):
    return string.endswith("_grad")


def IsPlainTensorType(string):
    plain_tensor_types = ['Tensor&', 'Tensor', 'const Tensor&', 'const Tensor']
    if string in plain_tensor_types:
        return True
    return False


def IsVectorTensorType(string):
    vector_tensor_types = [
        'std::vector<std::vector<Tensor>>', 'std::vector<Tensor>'
    ]
    if string in vector_tensor_types:
        return True
    return False


def GetSavedName(string):
    return string + "_"


def GetConstReference(string):
    ret = string
    if not string.startswith("const "):
        ret = "const " + string
    if not string.endswith("&"):
        ret += "&"
    return ret


def RemoveConstAndReference(string):
    ret = string
    if string.startswith("const "):
        ret = ret[6:]
    if string.endswith("&"):
        ret = ret[:-1]

    return ret


def GetGradNodeName(string):
    return f"FinalGradNode{string}"


def GetDygraphForwardFunctionName(string):
    return f"{string}_final_state_dygraph_function"


def GetIntermediateAPIFunctionName(string):
    return string + "_intermediate"


def GetAutoGradMetaName(string):
    return f"{string}_autograd_meta"


def GetAutoGradMetaVectorName(string):
    return f"{string}_autograd_meta_vec"


def RemoveSpecialSymbolsInName(string):
    # Remove any name after '@'
    ret = string.split("@")[0]
    return ret


def RecoverBaseNameOfInplaceFunction(function_name):
    return function_name[:-1]


def GetInplacedFunctionName(function_name):
    return function_name + "_"


def GetForwardFunctionName(string):
    return f"{string}_final_state_dygraph_function"


def TransformGradVarNameForDoubleGradGeneration(string):
    if IsGradName(string):
        string = "grad_" + string[:-5]
    return string


def GetIndent(num):
    tab = "   "
    return "".join([tab for i in range(num)])


######################
###  Yaml Parsers  ###
######################
def ParseYamlArgs(string):
    # Example: const Tensor& x, const Tensor& y, bool transpose_x, bool transpose_y

    # inputs_list = [ [arg_name, arg_type, orig_position], ...]
    inputs_list = []
    # attrs_list = [ [arg_name, arg_type, default_value, orig_position], ...]
    attrs_list = []

    args = [x.strip() for x in string.strip().split(",")]
    atype = r'((const )?\S+) '
    aname = r'(.*)'
    pattern = f'{atype}{aname}'
    for i in range(len(args)):
        arg = args[i]
        m = re.search(pattern, arg)
        arg_type = m.group(1).strip()
        arg_name = m.group(3).split("=")[0].strip()
        default_value = m.group(3).split("=")[1].strip() if len(
            m.group(3).split("=")) > 1 else None

        assert arg_type in yaml_types_mapping.keys(
        ), f"The argument type {arg_type} in yaml config is not supported in yaml_types_mapping."
        arg_type = yaml_types_mapping[arg_type]

        arg_name = RemoveSpecialSymbolsInName(arg_name)
        if "Tensor" in arg_type:
            assert default_value is None
            inputs_list.append([arg_name, arg_type, i])
        else:
            attrs_list.append([arg_name, arg_type, default_value, i])

    return inputs_list, attrs_list


def ParseYamlReturns(string):
    # Example0: Tensor(out), Tensor(out1)
    # Example1: Tensor, Tensor
    # Example2: Tensor[](out), Tensor

    # list = [ [ret_name, ret_type, orig_position], ...]
    returns_list = []

    returns = [x.strip() for x in string.strip().split(",")]

    for i in range(len(returns)):
        ret = returns[i]

        ret_name = ""
        if "(" in ret and ")" in ret:
            # Remove trailing ')'
            ret = ret[:-1]
            ret_type = ret.split("(")[0].strip()
            ret_name = ret.split("(")[1].strip()
        else:
            ret_type = ret.strip()

        assert ret_type in yaml_types_mapping.keys(
        ), f"The return type {ret_type} in yaml config is not supported in yaml_types_mapping."
        ret_type = yaml_types_mapping[ret_type]

        assert "Tensor" in ret_type, AssertMessage("Tensor", ret_type)
        ret_name = RemoveSpecialSymbolsInName(ret_name)
        returns_list.append([ret_name, ret_type, i])

    return returns_list


def ParseYamlForwardFromBackward(string):
    # Example: matmul (const Tensor& x, const Tensor& y, bool transpose_x, bool transpose_y) -> Tensor(out)

    fname = r'(.*?)'
    wspace = r'\s*'
    fargs = r'(.*?)'
    frets = r'(.*)'
    pattern = f'{fname}{wspace}\({wspace}{fargs}{wspace}\){wspace}->{wspace}{frets}'

    m = re.search(pattern, string)
    function_name = m.group(1)
    function_args = m.group(2)
    function_returns = m.group(3)

    forward_inputs_list, forward_attrs_list = ParseYamlArgs(function_args)
    forward_returns_list = ParseYamlReturns(function_returns)

    return forward_inputs_list, forward_attrs_list, forward_returns_list


def ParseYamlForward(args_str, returns_str):
    # args Example: (const Tensor& x, const Tensor& y, bool transpose_x = false, bool transpose_y = false)
    # returns Example: Tensor, Tensor

    fargs = r'(.*?)'
    wspace = r'\s*'
    args_pattern = f'^\({fargs}\)$'
    args_str = re.search(args_pattern, args_str.strip()).group(1)

    inputs_list, attrs_list = ParseYamlArgs(args_str)
    returns_list = ParseYamlReturns(returns_str)

    return inputs_list, attrs_list, returns_list


def ParseYamlBackward(args_str, returns_str):
    # args Example: (const Tensor& x, const Tensor& y, const Tensor& out_grad, bool transpose_x=false, bool transpose_y=false)
    # returns Example: Tensor(x_grad), Tensor(y_grad)

    fargs = r'(.*?)'
    wspace = r'\s*'
    args_pattern = f'\({fargs}\)'
    args_str = re.search(args_pattern, args_str).group(1)

    inputs_list, attrs_list = ParseYamlArgs(args_str)
    returns_list = ParseYamlReturns(returns_str)

    return inputs_list, attrs_list, returns_list


########################
###  Generator Base  ###
########################
class FunctionGeneratorBase:
    def __init__(self, forward_api_contents, namespace):
        self.forward_api_contents = forward_api_contents
        self.namespace = namespace

        self.forward_api_name = ""

        self.orig_forward_inputs_list = [
        ]  #[ [arg_name, arg_type, orig_position], ...]
        self.orig_forward_attrs_list = [
        ]  #[ [attr_name, attr_type, default_value, orig_position], ...]
        self.orig_forward_returns_list = [
        ]  #[ [ret_name, ret_type, orig_position], ...]

        # Processed Forward Data
        self.forward_inputs_position_map = {
        }  #{ "name" : [type, fwd_position] }
        self.forward_outputs_position_map = {
        }  #{ "name" : [type, fwd_position] }

        # Special Op Attributes
        self.optional_inputs = []  #[name, ...]
        self.no_need_buffers = []  #[name, ...]
        self.intermediate_outputs = []  #[name, ...]    
        self.inplace_map = {}  #{name : name, ...}

    def ParseInplaceInfo(self):
        forward_api_contents = self.forward_api_contents
        if 'inplace' not in forward_api_contents.keys(): return

        # inplace_map_str: "(x -> out0), (y -> out2)"
        inplace_map_str = forward_api_contents['inplace']
        for pair in inplace_map_str.split(","):
            pair = pair.strip()
            if pair.startswith("("):
                pair = pair[1:]

            if pair.endswith(")"):
                pair = pair[:-1]

            key = pair.split("->")[0].strip()
            val = pair.split("->")[1].strip()
            self.inplace_map[key] = val

    def ParseNoNeedBuffer(self):
        grad_api_contents = self.grad_api_contents

        if 'no_need_buffer' in grad_api_contents.keys():
            no_need_buffer_str = grad_api_contents['no_need_buffer']
            for name in no_need_buffer_str.split(","):
                name = name.strip()
                name = RemoveSpecialSymbolsInName(name)
                self.no_need_buffers.append(name.strip())

    def ParseDispensable(self):
        forward_api_contents = self.forward_api_contents

        if 'optional' in forward_api_contents.keys():
            optional_inputs_str = forward_api_contents['optional']
            for name in optional_inputs_str.split(","):
                name = name.strip()
                name = RemoveSpecialSymbolsInName(name)
                self.optional_inputs.append(name)

    def ParseIntermediate(self):
        forward_api_contents = self.forward_api_contents

        if 'intermediate' in forward_api_contents.keys():
            intermediate_str = forward_api_contents['intermediate']
            for name in intermediate_str.split(","):
                name = name.strip()
                name = RemoveSpecialSymbolsInName(name)
                self.intermediate_outputs.append(name)

    def CollectOriginalForwardInfo(self):
        forward_api_contents = self.forward_api_contents

        self.forward_api_name = forward_api_contents['api']
        forward_args_str = forward_api_contents['args']
        forward_returns_str = forward_api_contents['output']

        assert 'api' in forward_api_contents.keys(
        ), "Unable to find \"api\" in forward_api_contents keys"
        assert 'args' in forward_api_contents.keys(
        ), "Unable to find \"args\" in forward_api_contents keys"
        assert 'output' in forward_api_contents.keys(
        ), "Unable to find \"output\" in forward_api_contents keys"

        # Collect Original Forward Inputs/Outputs and then perform validation checks
        self.orig_forward_inputs_list, self.orig_forward_attrs_list, self.orig_forward_returns_list = ParseYamlForward(
            forward_args_str, forward_returns_str)

    def DetermineForwardPositionMap(self, forward_inputs_list,
                                    forward_returns_list):
        for i in range(len(forward_inputs_list)):
            forward_input = forward_inputs_list[i]
            input_name = forward_input[0]
            input_type = forward_input[1]
            input_pos = forward_input[2]

            self.forward_inputs_position_map[
                input_name] = [input_type, input_pos]

        for i in range(len(forward_returns_list)):
            forward_return = forward_returns_list[i]
            return_name = forward_return[0]
            return_type = forward_return[1]
            return_pos = forward_return[2]

            self.forward_outputs_position_map[
                return_name] = [return_type, return_pos]
        print("Generated Forward Input Position Map: ",
              self.forward_inputs_position_map)
        print("Generated Forward Output Position Map: ",
              self.forward_outputs_position_map)


class YamlGeneratorBase:
    def __init__(self, api_yaml_path):
        self.namespace = ""
        self.api_yaml_path = api_yaml_path

        self.forward_api_list = []

    def ParseForwardYamlContents(self):
        api_yaml_path = self.api_yaml_path
        self.forward_api_list = ReadFwdFile(api_yaml_path)

    def InferNameSpace(self):
        api_yaml_path = self.api_yaml_path
        if "sparse" in api_yaml_path:
            self.namespace = "sparse::"
        elif "strings" in api_yaml_path:
            self.namespace = "strings::"
