# Copyright (c) Microsoft Corporation. All rights reserved.
# Licensed under the MIT License.

import hashlib
import itertools
import json
import logging
import re
from copy import deepcopy
from typing import Any, List, Optional, Union

import generator.model as model

LSP_MAX_INT = 2**31 - 1
LSP_MIN_INT = -(2**31)

LSP_MAX_UINT = 2**31 - 1
LSP_MIN_UINT = 0

LSP_OVER_MAX_INT = 2**31
LSP_UNDER_MIN_INT = -(2**31) - 1

LSP_OVER_MAX_UINT = 2**32 + 1
LSP_UNDER_MIN_UINT = -1


def get_hash_from(text: str) -> str:
    return hashlib.sha256(text.encode("utf-8")).hexdigest()


def request_variants(method: str):
    for id_value in [1, LSP_MAX_INT, LSP_MIN_INT, "string-id-1"]:
        yield True, {"jsonrpc": "2.0", "id": id_value, "method": method}
    for id_value in [LSP_OVER_MAX_INT, LSP_UNDER_MIN_INT, 1.0, True, None]:
        yield False, {"jsonrpc": "2.0", "id": id_value, "method": method}
    yield False, {"jsonrpc": "2.0", "method": method}
    yield False, {"jsonrpc": "2.0", "id": 1}
    yield False, {"id": 1, "method": method}


def response_variants():
    for id_value in [1, LSP_MAX_INT, LSP_MIN_INT, "string-id-1"]:
        yield True, {"jsonrpc": "2.0", "id": id_value}
    for id_value in [LSP_OVER_MAX_INT, LSP_UNDER_MIN_INT, 1.0, True, None]:
        yield False, {"jsonrpc": "2.0", "id": id_value}
    yield False, {"jsonrpc": "2.0"}
    yield False, {"id": 1}


def notify_variants(method: str):
    yield True, {"jsonrpc": "2.0", "method": method}
    yield False, {"jsonrpc": "2.0", "id": 1, "method": method}


def _get_struct(name: str, spec: model.LSPModel) -> Optional[model.Structure]:
    for struct in spec.structures:
        if struct.name == name:
            return struct
    return None


def _get_type_alias(name: str, spec: model.LSPModel) -> Optional[model.TypeAlias]:
    for alias in spec.typeAliases:
        if alias.name == name:
            return alias
    return None


def _get_enum(name: str, spec: model.LSPModel) -> Optional[model.Enum]:
    for enum in spec.enumerations:
        if enum.name == name:
            return enum
    return None


class Ignore:
    pass


def extend(arr: List[Any], length: int) -> List[Any]:
    result = arr * (length // len(arr)) + arr[: length % len(arr)]
    return result


def extend_all(lists: List[List[Any]]) -> List[List[Any]]:
    max_len = max(len(part) for part in lists)
    max_len = min(1000, max_len)
    return [extend(part, max_len) for part in lists]


def has_null_base_type(items: List[model.LSP_TYPE_SPEC]) -> bool:
    return any(item.kind == "base" and item.name == "null" for item in items)


def filter_null_base_type(
    items: List[model.LSP_TYPE_SPEC],
) -> List[model.LSP_TYPE_SPEC]:
    return [item for item in items if not (item.kind == "base" and item.name == "null")]


def generate_for_base(name: str):
    if name == "string":
        yield (True, "some string 🐍🐜")
        yield (True, "")
    elif name == "integer":
        yield (True, 1)
        yield (True, LSP_MAX_INT)
        yield (True, LSP_MIN_INT)
        yield (False, LSP_OVER_MAX_INT)
        yield (False, LSP_UNDER_MIN_INT)
    elif name == "decimal":
        yield (True, 1.0)
    elif name == "boolean":
        yield (True, True)
        yield (True, False)
    elif name == "null":
        yield (True, None)
    elif name == "uinteger":
        yield (True, 1)
        yield (True, LSP_MAX_UINT)
        yield (True, LSP_MIN_UINT)
        yield (False, LSP_OVER_MAX_UINT)
        yield (False, LSP_UNDER_MIN_UINT)
    elif name in ["URI", "DocumentUri"]:
        yield (True, "file:///some/path")
    elif name == "RegExp":
        yield (True, ".*")


def generate_for_array(
    type_def: model.LSP_TYPE_SPEC, spec: model.LSPModel, visited: List[str]
):
    generated = list(generate_for_type(type_def, spec, visited))
    yield (True, [])

    # array with 1 item
    for valid, value in generated:
        if not isinstance(value, Ignore):
            yield (valid, [value])

    # array with 2 items
    generated = generated[:100] if len(generated) > 100 else generated
    values = itertools.product(generated, repeat=2)
    for (valid1, value1), (valid2, value2) in values:
        if not isinstance(value1, Ignore) and not isinstance(value2, Ignore):
            yield (valid1 and valid2, [value1, value2])


def generate_for_tuple(
    type_defs: List[model.LSP_TYPE_SPEC], spec: model.LSPModel, visited: List[str]
):
    generated = [
        list(generate_for_type(type_def, spec, visited)) for type_def in type_defs
    ]
    products = zip(*extend_all(generated))

    for product in products:
        is_valid = all(valid for valid, _ in product)
        values = [value for _, value in product if not isinstance(value, Ignore)]
        yield (is_valid, tuple(values))


def generate_for_map(
    key_def: model.LSP_TYPE_SPEC,
    value_def: model.LSP_TYPE_SPEC,
    spec: model.LSPModel,
    visited: List[str],
):
    key_values = list(generate_for_type(key_def, spec, visited))
    value_values = list(generate_for_type(value_def, spec, visited))

    for key_valid, key_value in key_values:
        for value_valid, value_value in value_values:
            if not (isinstance(key_value, Ignore) or isinstance(value_value, Ignore)):
                yield (key_valid and value_valid, {key_value: value_value})


def get_all_extends(struct_def: model.Structure, spec) -> List[model.Structure]:
    extends = []
    for extend in struct_def.extends:
        extends.append(_get_struct(extend.name, spec))
        for struct in get_all_extends(_get_struct(extend.name, spec), spec):
            if not any(struct.name == e.name for e in extends):
                extends.append(struct)
    return extends


def get_all_properties(struct: model.Structure, spec) -> List[model.Property]:
    properties = []
    for prop in struct.properties:
        properties.append(prop)

    for extend in get_all_extends(struct, spec):
        for prop in get_all_properties(extend, spec):
            if not any(prop.name == p.name for p in properties):
                properties.append(prop)

    if not all(mixin.kind == "reference" for mixin in struct.mixins):
        raise ValueError(f"Struct {struct.name} has non-reference mixins")
    for mixin in [_get_struct(mixin.name, spec) for mixin in struct.mixins]:
        for prop in get_all_properties(mixin, spec):
            if not any(prop.name == p.name for p in properties):
                properties.append(prop)

    return properties


def generate_for_property(
    prop: model.Property, spec: model.LSPModel, visited: List[str]
):
    if prop.optional:
        yield (True, Ignore())
    yield from generate_for_type(prop.type, spec, visited)


def generate_for_reference(
    refname: str,
    spec: model.LSPModel,
    visited: List[str],
):
    if len([name for name in visited if name == refname]) > 2:
        return

    ref = _get_struct(refname, spec)
    alias = _get_type_alias(refname, spec)
    enum = _get_enum(refname, spec)
    if ref:
        properties = get_all_properties(ref, spec)
        if properties:
            names = [prop.name for prop in properties]
            value_variants = [
                list(generate_for_property(prop, spec, visited)) for prop in properties
            ]

            products = zip(*extend_all(value_variants))
            for variants in products:
                is_valid = all(valid for valid, _ in variants)
                values = [value for _, value in variants]
                variant = {
                    name: value
                    for name, value in zip(names, values)
                    if not isinstance(value, Ignore)
                }
                yield (is_valid, variant)
        else:
            yield (True, {"lspExtension": "some value"})
            yield (True, dict())
    elif alias:
        if refname in ["LSPObject", "LSPAny", "LSPArray"]:
            yield from (
                (True, value)
                for _, value in generate_for_type(alias.type, spec, visited)
            )
        else:
            yield from generate_for_type(alias.type, spec, visited)
    elif enum:
        value = enum.values[0].value
        yield (True, value)
        if isinstance(value, int):
            yield (bool(enum.supportsCustomValues), 12345)
        elif isinstance(value, str):
            yield (bool(enum.supportsCustomValues), "testCustomValue")
    else:
        raise ValueError(f"Unknown reference {refname}")


def generate_for_or(
    type_defs: List[model.LSP_TYPE_SPEC],
    spec: model.LSPModel,
    visited: List[str],
):
    if has_null_base_type(type_defs):
        yield (True, None)

    subset = filter_null_base_type(type_defs)
    generated = [
        list(generate_for_type(type_def, spec, visited)) for type_def in subset
    ]
    for valid, value in itertools.chain(*generated):
        yield (valid, value)


def generate_for_and(
    type_defs: List[model.LSP_TYPE_SPEC],
    spec: model.LSPModel,
    visited: List[str],
):
    generated = [
        list(generate_for_type(type_def, spec, visited)) for type_def in type_defs
    ]
    products = zip(*extend_all(generated))
    for variants in products:
        is_valid = all(valid for valid, _ in variants)
        values = [value for _, value in variants]
        variant = {}
        for value in values:
            variant.update(value)
        yield (is_valid, variant)


def generate_for_literal(
    type_def: model.LiteralType,
    spec: model.LSPModel,
    visited: List[str],
):
    if type_def.value.properties:
        names = [prop.name for prop in type_def.value.properties]
        value_variants = [
            list(generate_for_type(prop.type, spec, visited))
            for prop in type_def.value.properties
        ]

        products = zip(*extend_all(value_variants))
        for variants in products:
            is_valid = all(valid for valid, _ in variants)
            values = [value for _, value in variants]
            variant = {name: value for name, value in zip(names, values)}
            yield (is_valid, variant)
    else:
        # Literal with no properties are a way to extend LSP spec
        # see: https://github.com/microsoft/vscode-languageserver-node/issues/997
        yield (True, {"lspExtension": "some value"})
        yield (True, dict())


def generate_for_type(
    type_def: model.LSP_TYPE_SPEC,
    spec: model.LSPModel,
    visited: List[str],
):
    if type_def is None:
        yield (True, None)
    elif type_def.kind == "base":
        yield from generate_for_base(type_def.name)
    elif type_def.kind == "array":
        yield from generate_for_array(type_def.element, spec, visited)
    elif type_def.kind == "reference":
        yield from generate_for_reference(
            type_def.name, spec, visited + [type_def.name]
        )
    elif type_def.kind == "stringLiteral":
        yield (True, type_def.value)
        # yield (False, f"invalid@{type_def.value}")
    elif type_def.kind == "tuple":
        yield from generate_for_tuple(type_def.items, spec, visited)
    elif type_def.kind == "or":
        yield from generate_for_or(type_def.items, spec, visited)
    elif type_def.kind == "and":
        yield from generate_for_and(type_def.items, spec, visited)
    elif type_def.kind == "literal":
        yield from generate_for_literal(type_def, spec, visited)
    elif type_def.kind == "map":
        yield from generate_for_map(type_def.key, type_def.value, spec, visited)


def generate_requests(request: model.Request, spec: model.LSPModel):
    variants = zip(
        *extend_all(
            [
                list(request_variants(request.method)),
                list(generate_for_type(request.params, spec, [])),
            ]
        )
    )

    for (valid1, base), (valid2, params) in variants:
        valid = valid1 and valid2
        if isinstance(params, Ignore):
            yield (valid, base)
        else:
            message = deepcopy(base)
            message.update({"params": params})
            yield (valid1 and valid2, message)


def generate_notifications(notify: model.Notification, spec: model.LSPModel):
    variants = zip(
        *extend_all(
            [
                list(notify_variants(notify.method)),
                list(generate_for_type(notify.params, spec, [])),
            ]
        )
    )

    for (valid1, base), (valid2, params) in variants:
        valid = valid1 and valid2
        if isinstance(params, Ignore):
            yield (valid, base)
        else:
            message = deepcopy(base)
            message.update({"params": params})
            yield (valid1 and valid2, message)


RESPONSE_ERROR = model.Structure(
    **{
        "name": "ResponseError",
        "properties": [
            {
                "name": "code",
                "type": {"kind": "base", "name": "integer"},
            },
            {
                "name": "message",
                "type": {"kind": "base", "name": "string"},
            },
            {
                "name": "data",
                "type": {"kind": "reference", "name": "LSPObject"},
                "optional": True,
            },
        ],
    }
)


def generate_responses(request: model.Request, spec: model.LSPModel):
    variants = zip(
        *extend_all(
            [
                list(response_variants()),
                list(generate_for_type(request.result, spec, [])),
                list(
                    generate_for_type(
                        model.ReferenceType("reference", "ResponseError"), spec, []
                    )
                ),
            ]
        )
    )

    for (valid1, base), (valid2, result), (valid3, error) in variants:
        valid = valid1 and valid2 and valid3
        if isinstance(result, Ignore):
            yield (valid, base)
        else:
            message = deepcopy(base)
            message.update({"result": result})
            message.update({"error": error})
            yield (valid, message)


PARTS_RE = re.compile(r"(([a-z0-9])([A-Z]))")


def get_parts(name: str) -> List[str]:
    name = name.replace("_", " ")
    return PARTS_RE.sub(r"\2 \3", name).split()


def to_upper_camel_case(name: str) -> str:
    return "".join([c.capitalize() for c in get_parts(name)])


def lsp_method_to_name(method: str) -> str:
    if method.startswith("$"):
        method = method[1:]
    method = method.replace("/", "_")
    return to_upper_camel_case(method)


def get_name(obj: Union[model.Request, model.Notification]) -> str:
    if obj.typeName:
        return obj.typeName
    return lsp_method_to_name(obj.method)


def generate(spec: model.LSPModel, logger: logging.Logger):
    spec.structures.append(RESPONSE_ERROR)
    testdata = {}
    for request in spec.requests:
        request_name = get_name(request)
        if not request_name.endswith("Request"):
            request_name = f"{request_name}Request"
        response_name_part = request_name.replace("Request", "")
        response_name = f"{response_name_part}Response"
        counter = 0
        for valid, value in generate_requests(request, spec):
            content = json.dumps(value, indent=4, ensure_ascii=False)
            name = f"{request_name}-{valid}-{get_hash_from(content)}.json"
            if name in testdata:
                continue
            testdata[name] = content
            counter += 1
        logger.info(f"Generated {counter} variants for Request: {request.method}")

        for valid, value in generate_responses(request, spec):
            content = json.dumps(value, indent=4, ensure_ascii=False)
            name = f"{response_name}-{valid}-{get_hash_from(content)}.json"
            if name in testdata:
                continue
            testdata[name] = content
            counter += 1
        logger.info(f"Generated {counter} variants for Response: {request.method}")

    for notify in spec.notifications:
        notification_name = get_name(notify)
        if not notification_name.endswith("Notification"):
            notification_name = f"{notification_name}Notification"
        counter = 0
        for valid, value in generate_notifications(notify, spec):
            content = json.dumps(value, indent=4, ensure_ascii=False)
            name = f"{notification_name}-{valid}-{get_hash_from(content)}.json"
            if name in testdata:
                continue
            testdata[name] = content
            counter += 1
        logger.info(f"Generated {counter} variants for Notification: {notify.method}")

    logger.info(f"Generated {len(testdata)} test variants")
    return testdata
