from __future__ import annotations

from typing import TYPE_CHECKING, Sequence
from dataclasses import replace

from pystencils import CreateKernelConfig, create_kernel
from pystencils.astnodes import KernelFunction

if TYPE_CHECKING:
    from .context import SfgContext
    from .tree import SfgCallTreeNode


class SfgHeaderInclude:
    def __init__(self, header_file: str, system_header: bool = False, private: bool = False):
        self._header_file = header_file
        self._system_header = system_header
        self._private = private

    @property
    def system_header(self):
        return self._system_header

    @property
    def private(self):
        return self._private

    def get_code(self):
        if self._system_header:
            return f"#include <{self._header_file}>"
        else:
            return f'#include "{self._header_file}"'

    def __hash__(self) -> int:
        return hash((self._header_file, self._system_header, self._private))

    def __eq__(self, other: object) -> bool:
        return (isinstance(other, SfgHeaderInclude)
                and self._header_file == other._header_file
                and self._system_header == other._system_header
                and self._private == other._private)


class SfgKernelNamespace:
    def __init__(self, ctx, name: str):
        self._ctx = ctx
        self._name = name
        self._asts: dict[str, KernelFunction] = dict()

    @property
    def name(self):
        return self._name

    @property
    def asts(self):
        yield from self._asts.values()

    def add(self, ast: KernelFunction, name: str | None = None):
        """Adds an existing pystencils AST to this namespace.
        If a name is specified, the AST's function name is changed."""
        if name is not None:
            astname = name
        else:
            astname = ast.function_name

        if astname in self._asts:
            raise ValueError(f"Duplicate ASTs: An AST with name {astname} already exists in namespace {self._name}")

        if name is not None:
            ast.function_name = name

        self._asts[astname] = ast

        return SfgKernelHandle(self._ctx, astname, self, ast.get_parameters())

    def create(self, assignments, name: str | None = None, config: CreateKernelConfig | None = None):
        """Creates a new pystencils kernel from a list of assignments and a configuration.
        This is a wrapper around
        [`pystencils.create_kernel`](
            https://pycodegen.pages.i10git.cs.fau.de/pystencils/
            sphinx/kernel_compile_and_call.html#pystencils.create_kernel
        )
        with a subsequent call to [`add`][pystencilssfg.source_components.SfgKernelNamespace.add].
        """
        if config is None:
            config = CreateKernelConfig()

        if name is not None:
            if name in self._asts:
                raise ValueError(f"Duplicate ASTs: An AST with name {name} already exists in namespace {self._name}")
            config = replace(config, function_name=name)

        # type: ignore
        ast = create_kernel(assignments, config=config)
        return self.add(ast)


class SfgKernelHandle:
    def __init__(self, ctx, name: str, namespace: SfgKernelNamespace, parameters: Sequence[KernelFunction.Parameter]):
        self._ctx = ctx
        self._name = name
        self._namespace = namespace
        self._parameters = parameters

        self._scalar_params = set()
        self._fields = set()

        for param in self._parameters:
            if param.is_field_parameter:
                self._fields |= set(param.fields)
            else:
                self._scalar_params.add(param.symbol)

    @property
    def kernel_name(self):
        return self._name

    @property
    def kernel_namespace(self):
        return self._namespace

    @property
    def fully_qualified_name(self):
        match self._ctx.fully_qualified_namespace:
            case None: return f"{self.kernel_namespace.name}::{self.kernel_name}"
            case fqn: return f"{fqn}::{self.kernel_namespace.name}::{self.kernel_name}"

    @property
    def parameters(self):
        return self._parameters

    @property
    def scalar_parameters(self):
        return self._scalar_params

    @property
    def fields(self):
        return self.fields


class SfgFunction:
    def __init__(self, ctx: SfgContext, name: str, tree: SfgCallTreeNode):
        self._ctx = ctx
        self._name = name
        self._tree = tree

        from .tree.visitors import ExpandingParameterCollector

        param_collector = ExpandingParameterCollector(self._ctx)
        self._parameters = param_collector.visit(self._tree)

    @property
    def name(self):
        return self._name

    @property
    def parameters(self):
        return self._parameters

    @property
    def tree(self):
        return self._tree

    def get_code(self):
        return self._tree.get_code(self._ctx)