#!/usr/bin/env python3
#
# Copyright (C) 2022-2023 VyOS maintainers and contributors
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License version 2 or later as
# published by the Free Software Foundation.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.
#
#
# A utility to generate GraphQL schema defintions from standardized op-mode
# scripts.

import os
import sys
import json
from inspect import signature, getmembers, isfunction, isclass, getmro
from jinja2 import Template

from vyos.defaults import directories
from vyos.opmode import _is_op_mode_function_name as is_op_mode_function_name
from vyos.opmode import _get_literal_values as get_literal_values
from vyos.utils.system import load_as_module
if __package__ is None or __package__ == '':
    sys.path.append(os.path.join(directories['services'], 'api'))
    from graphql.libs.op_mode import is_show_function_name
    from graphql.libs.op_mode import snake_to_pascal_case, map_type_name
else:
    from .. libs.op_mode import is_show_function_name
    from .. libs.op_mode import snake_to_pascal_case, map_type_name

OP_MODE_PATH = directories['op_mode']
SCHEMA_PATH = directories['api_schema']
CLIENT_OP_PATH = directories['api_client_op']
DATA_DIR = directories['data']


op_mode_include_file = os.path.join(DATA_DIR, 'op-mode-standardized.json')
op_mode_error_schema = 'op_mode_error.graphql'

schema_data: dict = {'schema_name': '',
                     'schema_fields': []}

query_template  = """
input {{ schema_name }}Input {
    key: String
    {%- for field_entry in schema_fields %}
    {{ field_entry }}
    {%- endfor %}
}

type {{ schema_name }} {
    result: Generic
}

type {{ schema_name }}Result {
    data: {{ schema_name }}
    op_mode_error: OpModeError
    success: Boolean!
    errors: [String]
}

extend type Query {
    {{ schema_name }}(data: {{ schema_name }}Input) : {{ schema_name }}Result @genopquery
}
"""

mutation_template  = """
input {{ schema_name }}Input {
    key: String
    {%- for field_entry in schema_fields %}
    {{ field_entry }}
    {%- endfor %}
}

type {{ schema_name }} {
    result: Generic
}

type {{ schema_name }}Result {
    data: {{ schema_name }}
    op_mode_error: OpModeError
    success: Boolean!
    errors: [String]
}

extend type Mutation {
    {{ schema_name }}(data: {{ schema_name }}Input) : {{ schema_name }}Result @genopmutation
}
"""

enum_template = """
enum {{ enum_name }} {
    {%- for field_entry in enum_fields %}
    {{ field_entry }}
    {%- endfor %}
}
"""

error_template = """
interface OpModeError {
    name: String!
    message: String!
    vyos_code: Int!
}
{% for name in error_names %}
type {{ name }} implements OpModeError {
    name: String!
    message: String!
    vyos_code: Int!
}
{%- endfor %}
"""

op_query_template = """
query {{ op_name }} ({{ op_sig }}) {
  {{ op_name }} (data: { {{ op_arg }} }) {
    success
    errors
    op_mode_error {
      name
      message
      vyos_code
    }
    data {
      result
    }
  }
}
"""

op_mutation_template = """
mutation {{ op_name }} ({{ op_sig }}) {
  {{ op_name }} (data: { {{ op_arg }} }) {
    success
    errors
    op_mode_error {
      name
      message
      vyos_code
    }
    data {
      result
    }
  }
}
"""

def create_schema(func_name: str, base_name: str, func: callable,
                  enums: dict) -> str:
    sig = signature(func)

    for k in sig.parameters:
        t = get_literal_values(sig.parameters[k].annotation)
        if t:
            enums[t] = snake_to_pascal_case(sig.parameters[k].name + '_' + base_name)

    field_dict = {}
    for k in sig.parameters:
        field_dict[sig.parameters[k].name] = map_type_name(sig.parameters[k].annotation, enums)

    # It is assumed that if one is generating a schema for a 'show_*'
    # function, that 'get_raw_data' is present and 'raw' is desired.
    if 'raw' in list(field_dict):
        del field_dict['raw']

    schema_fields = []
    for k,v in field_dict.items():
        schema_fields.append(k+': '+v)

    schema_data['schema_name'] = snake_to_pascal_case(func_name + '_' + base_name)
    schema_data['schema_fields'] = schema_fields

    if is_show_function_name(func_name):
        j2_template = Template(query_template)
    else:
        j2_template = Template(mutation_template)

    res = j2_template.render(schema_data)

    return res

def create_client_op(func_name: str, base_name: str, func: callable,
                     enums: dict) -> str:
    sig = signature(func)

    for k in sig.parameters:
        t = get_literal_values(sig.parameters[k].annotation)
        if t:
            enums[t] = snake_to_pascal_case(sig.parameters[k].name + '_' + base_name)

    field_dict = {}
    for k in sig.parameters:
        field_dict[sig.parameters[k].name] = map_type_name(sig.parameters[k].annotation, enums)

    # It is assumed that if one is generating a schema for a 'show_*'
    # function, that 'get_raw_data' is present and 'raw' is desired.
    if 'raw' in list(field_dict):
        del field_dict['raw']

    op_sig = ['$key: String']
    op_arg = ['key: $key']
    for k,v in field_dict.items():
        op_sig.append('$'+k+': '+v)
        op_arg.append(k+': $'+k)

    op_data = {}
    op_data['op_name'] = snake_to_pascal_case(func_name + '_' + base_name)
    op_data['op_sig'] = ', '.join(op_sig)
    op_data['op_arg'] = ', '.join(op_arg)

    if is_show_function_name(func_name):
        j2_template = Template(op_query_template)
    else:
        j2_template = Template(op_mutation_template)

    res = j2_template.render(op_data)

    return res

def create_enums(enums: dict) -> str:
    enum_data = []
    for k, v in enums.items():
        enum = {'enum_name': v, 'enum_fields': list(k)}
        enum_data.append(enum)

    out = ''
    j2_template = Template(enum_template)
    for el in enum_data:
        out += j2_template.render(el)
        out += '\n'

    return out

def create_error_schema():
    from vyos import opmode

    e = Exception
    err_types = getmembers(opmode, isclass)
    err_types = [k for k in err_types if issubclass(k[1], e)]
    # drop base class, to be replaced by interface type. Find the class
    # programmatically, in case the base class name changes.
    for i in range(len(err_types)):
        if err_types[i][1] in getmro(err_types[i-1][1]):
            del err_types[i]
            break
    err_names = [k[0] for k in err_types]
    error_data = {'error_names': err_names}
    j2_template = Template(error_template)
    res = j2_template.render(error_data)

    return res

def generate_op_mode_definitions():
    os.makedirs(CLIENT_OP_PATH, exist_ok=True)

    out = create_error_schema()
    with open(f'{SCHEMA_PATH}/{op_mode_error_schema}', 'w') as f:
        f.write(out)

    with open(op_mode_include_file) as f:
        op_mode_files = json.load(f)

    for file in op_mode_files:
        basename = os.path.splitext(file)[0].replace('-', '_')
        module = load_as_module(basename, os.path.join(OP_MODE_PATH, file))

        funcs = getmembers(module, isfunction)
        funcs = list(filter(lambda ft: is_op_mode_function_name(ft[0]), funcs))

        funcs_dict = {}
        for (name, thunk) in funcs:
            funcs_dict[name] = thunk

        schema = []
        client_op = []
        enums = {} # gather enums from function Literal type args
        for name,func in funcs_dict.items():
            res = create_schema(name, basename, func, enums)
            schema.append(res)
            res = create_client_op(name, basename, func, enums)
            client_op.append(res)

        out = create_enums(enums)
        out += '\n'.join(schema)
        with open(f'{SCHEMA_PATH}/{basename}.graphql', 'w') as f:
            f.write(out)

        out = '\n'.join(client_op)
        with open(f'{CLIENT_OP_PATH}/{basename}.graphql', 'w') as f:
            f.write(out)

if __name__ == '__main__':
    generate_op_mode_definitions()