import operator
import os
import csv
import operator

from enum import Enum, auto
from typing import List, Set, ClassVar, Any
from dataclasses import dataclass, field

from ansi.color import fg

from cxxheaderparser.parser import CxxParser


# 'Fixing' complaints about typedefs
CxxParser._fundamentals.discard("wchar_t")

from cxxheaderparser.types import (
    EnumDecl,
    Field,
    ForwardDecl,
    FriendDecl,
    Function,
    Method,
    Typedef,
    UsingAlias,
    UsingDecl,
    Variable,
    Pointer,
    Type,
    PQName,
    NameSpecifier,
    FundamentalSpecifier,
    Parameter,
    Array,
    Value,
    Token,
    FunctionType,
)

from cxxheaderparser.parserstate import (
    State,
    EmptyBlockState,
    ClassBlockState,
    ExternBlockState,
    NamespaceBlockState,
)


@dataclass(frozen=True)
class ApiEntryFunction:
    name: str
    returns: str
    params: str

    csv_type: ClassVar[str] = "Function"

    def dictify(self):
        return dict(name=self.name, type=self.returns, params=self.params)


@dataclass(frozen=True)
class ApiEntryVariable:
    name: str
    var_type: str

    csv_type: ClassVar[str] = "Variable"

    def dictify(self):
        return dict(name=self.name, type=self.var_type, params=None)


@dataclass(frozen=True)
class ApiHeader:
    name: str

    csv_type: ClassVar[str] = "Header"

    def dictify(self):
        return dict(name=self.name, type=None, params=None)


@dataclass
class ApiEntries:
    # These are sets, to avoid creating duplicates when we have multiple
    # declarations with same signature
    functions: Set[ApiEntryFunction] = field(default_factory=set)
    variables: Set[ApiEntryVariable] = field(default_factory=set)
    headers: Set[ApiHeader] = field(default_factory=set)


class SymbolManager:
    def __init__(self):
        self.api = ApiEntries()
        self.name_hashes = set()

    # Calculate hash of name and raise exception if it already is in the set
    def _name_check(self, name: str):
        name_hash = gnu_sym_hash(name)
        if name_hash in self.name_hashes:
            raise Exception(f"Hash collision on {name}")
        self.name_hashes.add(name_hash)

    def add_function(self, function_def: ApiEntryFunction):
        if function_def in self.api.functions:
            return
        self._name_check(function_def.name)
        self.api.functions.add(function_def)

    def add_variable(self, variable_def: ApiEntryVariable):
        if variable_def in self.api.variables:
            return
        self._name_check(variable_def.name)
        self.api.variables.add(variable_def)

    def add_header(self, header: str):
        self.api.headers.add(ApiHeader(header))


def gnu_sym_hash(name: str):
    h = 0x1505
    for c in name:
        h = (h << 5) + h + ord(c)
    return str(hex(h))[-8:]


class SdkCollector:
    def __init__(self):
        self.symbol_manager = SymbolManager()

    def add_header_to_sdk(self, header: str):
        self.symbol_manager.add_header(header)

    def process_source_file_for_sdk(self, file_path: str):
        visitor = SdkCxxVisitor(self.symbol_manager)
        with open(file_path, "rt") as f:
            content = f.read()
        parser = CxxParser(file_path, content, visitor, None)
        parser.parse()

    def get_api(self):
        return self.symbol_manager.api


def stringify_array_dimension(size_descr):
    if not size_descr:
        return ""
    return stringify_descr(size_descr)


def stringify_array_descr(type_descr):
    assert isinstance(type_descr, Array)
    return (
        stringify_descr(type_descr.array_of),
        stringify_array_dimension(type_descr.size),
    )


def stringify_descr(type_descr):
    if isinstance(type_descr, (NameSpecifier, FundamentalSpecifier)):
        return type_descr.name
    elif isinstance(type_descr, PQName):
        return "::".join(map(stringify_descr, type_descr.segments))
    elif isinstance(type_descr, Pointer):
        # Hack
        if isinstance(type_descr.ptr_to, FunctionType):
            return stringify_descr(type_descr.ptr_to)
        return f"{stringify_descr(type_descr.ptr_to)}*"
    elif isinstance(type_descr, Type):
        return (
            f"{'const ' if type_descr.const else ''}"
            f"{'volatile ' if type_descr.volatile else ''}"
            f"{stringify_descr(type_descr.typename)}"
        )
    elif isinstance(type_descr, Parameter):
        return stringify_descr(type_descr.type)
    elif isinstance(type_descr, Array):
        # Hack for 2d arrays
        if isinstance(type_descr.array_of, Array):
            argtype, dimension = stringify_array_descr(type_descr.array_of)
            return (
                f"{argtype}[{stringify_array_dimension(type_descr.size)}][{dimension}]"
            )
        return f"{stringify_descr(type_descr.array_of)}[{stringify_array_dimension(type_descr.size)}]"
    elif isinstance(type_descr, Value):
        return " ".join(map(stringify_descr, type_descr.tokens))
    elif isinstance(type_descr, FunctionType):
        return f"{stringify_descr(type_descr.return_type)} (*)({', '.join(map(stringify_descr, type_descr.parameters))})"
    elif isinstance(type_descr, Token):
        return type_descr.value
    elif type_descr is None:
        return ""
    else:
        raise Exception("unsupported type_descr: %s" % type_descr)


class SdkCxxVisitor:
    def __init__(self, symbol_manager: SymbolManager):
        self.api = symbol_manager

    def on_variable(self, state: State, v: Variable) -> None:
        if not v.extern:
            return

        self.api.add_variable(
            ApiEntryVariable(
                stringify_descr(v.name),
                stringify_descr(v.type),
            )
        )

    def on_function(self, state: State, fn: Function) -> None:
        if fn.inline or fn.has_body:
            return

        self.api.add_function(
            ApiEntryFunction(
                stringify_descr(fn.name),
                stringify_descr(fn.return_type),
                ", ".join(map(stringify_descr, fn.parameters))
                + (", ..." if fn.vararg else ""),
            )
        )

    def on_define(self, state: State, content: str) -> None:
        pass

    def on_pragma(self, state: State, content: str) -> None:
        pass

    def on_include(self, state: State, filename: str) -> None:
        pass

    def on_empty_block_start(self, state: EmptyBlockState) -> None:
        pass

    def on_empty_block_end(self, state: EmptyBlockState) -> None:
        pass

    def on_extern_block_start(self, state: ExternBlockState) -> None:
        pass

    def on_extern_block_end(self, state: ExternBlockState) -> None:
        pass

    def on_namespace_start(self, state: NamespaceBlockState) -> None:
        pass

    def on_namespace_end(self, state: NamespaceBlockState) -> None:
        pass

    def on_forward_decl(self, state: State, fdecl: ForwardDecl) -> None:
        pass

    def on_typedef(self, state: State, typedef: Typedef) -> None:
        pass

    def on_using_namespace(self, state: State, namespace: List[str]) -> None:
        pass

    def on_using_alias(self, state: State, using: UsingAlias) -> None:
        pass

    def on_using_declaration(self, state: State, using: UsingDecl) -> None:
        pass

    def on_enum(self, state: State, enum: EnumDecl) -> None:
        pass

    def on_class_start(self, state: ClassBlockState) -> None:
        pass

    def on_class_field(self, state: State, f: Field) -> None:
        pass

    def on_class_method(self, state: ClassBlockState, method: Method) -> None:
        pass

    def on_class_friend(self, state: ClassBlockState, friend: FriendDecl) -> None:
        pass

    def on_class_end(self, state: ClassBlockState) -> None:
        pass


@dataclass(frozen=True)
class SdkVersion:
    major: int = 0
    minor: int = 0

    csv_type: ClassVar[str] = "Version"

    def __str__(self) -> str:
        return f"{self.major}.{self.minor}"

    def as_int(self) -> int:
        return ((self.major & 0xFFFF) << 16) | (self.minor & 0xFFFF)

    @staticmethod
    def from_str(s: str) -> "SdkVersion":
        major, minor = s.split(".")
        return SdkVersion(int(major), int(minor))

    def dictify(self) -> dict:
        return dict(name=str(self), type=None, params=None)


class VersionBump(Enum):
    NONE = auto()
    MAJOR = auto()
    MINOR = auto()


class ApiEntryState(Enum):
    PENDING = "?"
    APPROVED = "+"
    DISABLED = "-"
    # Special value for API version entry so users have less incentive to edit it
    VERSION_PENDING = "v"


# Class that stores all known API entries, both enabled and disabled.
# Also keeps track of API versioning
# Allows comparison and update from newly-generated API
class SdkCache:
    CSV_FIELD_NAMES = ("entry", "status", "name", "type", "params")

    def __init__(self, cache_file: str, load_version_only=False):
        self.cache_file_name = cache_file
        self.version = SdkVersion(0, 0)
        self.sdk = ApiEntries()
        self.disabled_entries = set()
        self.new_entries = set()
        self.loaded_dirty_version = False

        self.version_action = VersionBump.NONE
        self._load_version_only = load_version_only
        self.load_cache()

    def is_buildable(self) -> bool:
        return (
            self.version != SdkVersion(0, 0)
            and self.version_action == VersionBump.NONE
            and not self._have_pending_entries()
        )

    def _filter_enabled(self, sdk_entries):
        return sorted(
            filter(lambda e: e not in self.disabled_entries, sdk_entries),
            key=operator.attrgetter("name"),
        )

    def get_valid_names(self):
        syms = set(map(lambda e: e.name, self.get_functions()))
        syms.update(map(lambda e: e.name, self.get_variables()))
        return syms

    def get_functions(self):
        return self._filter_enabled(self.sdk.functions)

    def get_variables(self):
        return self._filter_enabled(self.sdk.variables)

    def get_headers(self):
        return self._filter_enabled(self.sdk.headers)

    def _get_entry_status(self, entry) -> str:
        if entry in self.disabled_entries:
            return ApiEntryState.DISABLED
        elif entry in self.new_entries:
            if isinstance(entry, SdkVersion):
                return ApiEntryState.VERSION_PENDING
            return ApiEntryState.PENDING
        else:
            return ApiEntryState.APPROVED

    def _format_entry(self, obj):
        obj_dict = obj.dictify()
        obj_dict.update(
            dict(
                entry=obj.csv_type,
                status=self._get_entry_status(obj).value,
            )
        )
        return obj_dict

    def save(self) -> None:
        if self._load_version_only:
            raise Exception("Only SDK version was loaded, cannot save")

        if self.version_action == VersionBump.MINOR:
            self.version = SdkVersion(self.version.major, self.version.minor + 1)
        elif self.version_action == VersionBump.MAJOR:
            self.version = SdkVersion(self.version.major + 1, 0)

        if self._have_pending_entries():
            self.new_entries.add(self.version)
            print(
                fg.red(
                    f"API version is still WIP: {self.version}. Review the changes and re-run command."
                )
            )
            print(f"CSV file entries to mark up:")
            print(
                fg.yellow(
                    "\n".join(
                        map(
                            str,
                            filter(
                                lambda e: not isinstance(e, SdkVersion),
                                self.new_entries,
                            ),
                        )
                    )
                )
            )
        else:
            print(fg.green(f"API version {self.version} is up to date"))

        regenerate_csv = (
            self.loaded_dirty_version
            or self._have_pending_entries()
            or self.version_action != VersionBump.NONE
        )

        if regenerate_csv:
            str_cache_entries = [self.version]
            name_getter = operator.attrgetter("name")
            str_cache_entries.extend(sorted(self.sdk.headers, key=name_getter))
            str_cache_entries.extend(sorted(self.sdk.functions, key=name_getter))
            str_cache_entries.extend(sorted(self.sdk.variables, key=name_getter))

            with open(self.cache_file_name, "wt", newline="") as f:
                writer = csv.DictWriter(f, fieldnames=SdkCache.CSV_FIELD_NAMES)
                writer.writeheader()

                for entry in str_cache_entries:
                    writer.writerow(self._format_entry(entry))

    def _process_entry(self, entry_dict: dict) -> None:
        entry_class = entry_dict["entry"]
        entry_status = entry_dict["status"]
        entry_name = entry_dict["name"]

        entry = None
        if entry_class == SdkVersion.csv_type:
            self.version = SdkVersion.from_str(entry_name)
            if entry_status == ApiEntryState.VERSION_PENDING.value:
                self.loaded_dirty_version = True
        elif entry_class == ApiHeader.csv_type:
            self.sdk.headers.add(entry := ApiHeader(entry_name))
        elif entry_class == ApiEntryFunction.csv_type:
            self.sdk.functions.add(
                entry := ApiEntryFunction(
                    entry_name,
                    entry_dict["type"],
                    entry_dict["params"],
                )
            )
        elif entry_class == ApiEntryVariable.csv_type:
            self.sdk.variables.add(
                entry := ApiEntryVariable(entry_name, entry_dict["type"])
            )
        else:
            print(entry_dict)
            raise Exception("Unknown entry type: %s" % entry_class)

        if entry is None:
            return

        if entry_status == ApiEntryState.DISABLED.value:
            self.disabled_entries.add(entry)
        elif entry_status == ApiEntryState.PENDING.value:
            self.new_entries.add(entry)

    def load_cache(self) -> None:
        if not os.path.exists(self.cache_file_name):
            raise Exception(
                f"Cannot load symbol cache '{self.cache_file_name}'! File does not exist"
            )

        with open(self.cache_file_name, "rt") as f:
            reader = csv.DictReader(f)
            for row in reader:
                self._process_entry(row)
                if self._load_version_only and row.get("entry") == SdkVersion.csv_type:
                    break

    def _have_pending_entries(self) -> bool:
        return any(
            filter(
                lambda e: not isinstance(e, SdkVersion),
                self.new_entries,
            )
        )

    def sync_sets(
        self, known_set: Set[Any], new_set: Set[Any], update_version: bool = True
    ):
        new_entries = new_set - known_set
        if new_entries:
            print(f"New: {new_entries}")
            known_set |= new_entries
            self.new_entries |= new_entries
            if update_version and self.version_action == VersionBump.NONE:
                self.version_action = VersionBump.MINOR
        removed_entries = known_set - new_set
        if removed_entries:
            print(f"Removed: {removed_entries}")
            known_set -= removed_entries
            # If any of removed entries was a part of active API, that's a major bump
            if update_version and any(
                filter(
                    lambda e: e not in self.disabled_entries
                    and e not in self.new_entries,
                    removed_entries,
                )
            ):
                self.version_action = VersionBump.MAJOR
            self.disabled_entries -= removed_entries
            self.new_entries -= removed_entries

    def validate_api(self, api: ApiEntries) -> None:
        self.sync_sets(self.sdk.headers, api.headers, False)
        self.sync_sets(self.sdk.functions, api.functions)
        self.sync_sets(self.sdk.variables, api.variables)