from __future__ import annotations

import re

from functools import cached_property
from typing import TYPE_CHECKING, override

from ..log import WARNING, log
from .base import Boundary, Lookup, Syntax
from .Version import Version

if TYPE_CHECKING:
    from collections.abc import Sequence
    from typing import ClassVar

class Dependency:  # export

    class Error(ValueError):
        pass

    __SPLIT_RE: ClassVar[re.Pattern[str]] = re.compile('([=><]+)')

    @cached_property
    def __parsed_spec(self) -> tuple[str, Boundary | None]:
        parts = [part.strip() for part in self.__SPLIT_RE.split(self.__spec)]
        match len(parts):
            case 1:
                if not parts[0]:
                    raise Dependency.Error(f'Invalid dependency spec "{self.__spec}"')
                return parts[0], None
            case 3:
                if not parts[0] or not parts[2]:
                    raise Dependency.Error(f'Invalid dependency spec "{self.__spec}"')
                if parts[2] == 'REVISION':
                    log(
                        WARNING,
                        f'Spec "{self.__spec}": a bare REVISION renders as a bare '
                        'number, which RPM reads as a version constraint, not a '
                        'release constraint'
                    )
                return parts[0], Boundary(
                    op = parts[1],
                    version = Version(parts[0], parts[2], self.__lookup_version),
                )
            case _:
                raise Dependency.Error(f'Invalid dependency spec "{self.__spec}"')

    def __version_boundaries(
        self,
        expanded: bool,
    ) -> Sequence[Boundary]:
        specified = self.__parsed_spec[1]
        if specified is None:
            return []
        if not expanded or not specified.version.is_full:
            return (specified, )
        ret: list[Boundary] = []
        match specified.op:
            case '>' | '>=':
                ret.append(specified)
                ret.append(Boundary('<', specified.version.next_binary_incompatible))
            case '=':
                ret.append(Boundary('>=', specified.version))
                ret.append(Boundary('<', specified.version.next_binary_incompatible))
            case '<' | '<=':
                ret.append(specified)
            case _:
                raise NotImplementedError(
                    (
                        'Expanding version boundary '
                        f'"{self.full_name} {specified.op} {specified.version}" '
                        'is not yet implemented'
                    )
                )
        return ret

    # -- Public API

    def __init__(
        self,
        spec: str,
        lookup_version: Lookup | None = None,
    ) -> None:
        self.__spec = spec
        self.__lookup_version = lookup_version

    @override
    def __str__(self) -> str:
        return self.__spec

    @cached_property
    def current_version(self) -> str:
        if not self.__lookup_version:
            raise Dependency.Error(
                f'Tried to look up "{self.__spec}" for package '
                f'"{self.base_name}" without lookup function'
            )
        return self.__lookup_version(self.base_name)

    @cached_property
    def full_name(self) -> str:
        return self.__parsed_spec[0]

    @cached_property
    def base_name(self) -> str:
        return Version.strip_package_suffix(self.full_name)

    def version_boundaries(self, expanded: bool = False) -> Sequence[Boundary]:
        return self.__version_boundaries(expanded)

    def constraint_str(
        self,
        syntax: Syntax = Syntax.SEM_VER,
        untemplated: bool = True,
        include_revision: bool = True,
        as_range: bool = False,
        no_subpackages: bool = False,
        quote: str | None = None,
    ) -> str:

        def __str() -> str:
            name = self.base_name if no_subpackages else self.full_name
            if syntax is Syntax.NAMES_ONLY:
                return name
            ret: list[str] = []
            for boundary in self.version_boundaries(expanded = as_range, ):
                op = boundary.format_op(syntax)
                version = boundary.version.id(untemplated, include_revision)
                ret.append(f'{name} {op} {version}')
            if ret:
                return ' '.join(ret)
            return name

        return __str() if quote is None else f'{quote}{__str()}{quote}'

    @classmethod
    def parse_deps_spec(
        cls,
        spec: str,
        lookup_version: Lookup | None = None,
    ) -> Sequence[Dependency]:
        return [
            Dependency(spec = spec.strip(), lookup_version = lookup_version)
            for spec in spec.split(',')
        ]