"""
Voting-related models: Voter, Antichain, VotedAntichain.
"""

from dataclasses import dataclass, field
from uuid import uuid4

from ..types import (
    AntichainId,
    VotedAntichainId,
)
from .core import Element, Poset


@dataclass
class Antichain:
    """An antichain in a posetspace - a set of mutually incomparable elements.

    An antichain is a collection of elements where no element is comparable to
    any other in the poset ordering. This structure is used in interactive voting
    to present pairs of elements for comparison.

    Attributes:
        element: The primary element of this antichain.
        id: Unique identifier for the antichain (auto-generated if not provided).
        comparisons: Set of elements to compare against the primary element.

    Examples:
        >>> # In a project prioritization context
        >>> from coposet.models.posetspace import PosetSpace
        >>> from coposet.types import PosetSpaceName, Description, ElementName
        >>>
        >>> project_space = PosetSpace(
        ...     name=PosetSpaceName("Projects"),
        ...     description=Description("Software project priorities")
        ... )
        >>>
        >>> # Create project elements
        >>> security = Element(
        ...     name=ElementName("Security Update"),
        ...     description=Description("Fix vulnerabilities"),
        ...     posetspace=project_space
        ... )
        >>> ui_redesign = Element(
        ...     name=ElementName("UI Redesign"),
        ...     description=Description("Improve user interface"),
        ...     posetspace=project_space
        ... )
        >>> performance = Element(
        ...     name=ElementName("Performance"),
        ...     description=Description("Optimize speed"),
        ...     posetspace=project_space
        ... )
        >>>
        >>> # Create antichain for voting
        >>> antichain = Antichain(
        ...     element=security,
        ...     comparisons={ui_redesign, performance}
        ... )
        >>> # User will be asked: Is Security Update more/less important than UI Redesign?
        >>> #                     Is Security Update more/less important than Performance?

    Note:
        In voting contexts, an antichain represents a set of pairwise comparisons
        that need to be resolved to extend the poset ordering.
    """

    element: Element
    id: AntichainId = field(default_factory=lambda: AntichainId(uuid4()))
    comparisons: set[Element] = field(default_factory=set)


@dataclass
class VotedAntichain:
    """Result of voting on an antichain.

    Represents the outcome of user voting on an antichain, specifying which
    elements were determined to be less than or greater than the primary element.

    Attributes:
        antichain: The antichain that was voted on.
        id: Unique identifier for the voting result (auto-generated if not provided).
        new_less: Set of elements determined to be less than antichain.element.
        new_greater: Set of elements determined to be greater than antichain.element.

    Examples:
        >>> # Continuing from the antichain example
        >>> # User voted that Security is more important than both others
        >>> voted_result = VotedAntichain(
        ...     antichain=antichain,
        ...     new_less={ui_redesign, performance},  # Both less important
        ...     new_greater=set()  # Nothing more important than security
        ... )
        >>> # This establishes: ui_redesign < security and performance < security
        >>>
        >>> # Alternative voting outcome with mixed preferences
        >>> mixed_vote = VotedAntichain(
        ...     antichain=antichain,
        ...     new_less={ui_redesign},      # UI less important
        ...     new_greater={performance}     # Performance more important
        ... )
        >>> # This establishes: ui_redesign < security < performance
        >>>
        >>> # Partial voting (user unsure about some comparisons)
        >>> partial_vote = VotedAntichain(
        ...     antichain=antichain,
        ...     new_less={ui_redesign},      # UI definitely less important
        ...     new_greater=set()             # Unsure about performance
        ... )
        >>> # Only establishes: ui_redesign < security
        >>> # security and performance remain incomparable

    Note:
        Elements not in new_less or new_greater remain incomparable with
        the antichain's primary element.
    """

    antichain: Antichain
    id: VotedAntichainId = field(default_factory=lambda: VotedAntichainId(uuid4()))
    new_less: set[Element] = field(default_factory=set)
    new_greater: set[Element] = field(default_factory=set)


@dataclass
class Voter:
    """A voter that can provide the next antichain to vote on.

    The Voter class implements the logic for interactive poset construction
    through sequential voting. It determines which comparisons need to be made
    and when the voting process is complete.

    Attributes:
        poset: The poset being constructed through voting.

    Examples:
        >>> from coposet.models.core import Poset
        >>> from coposet.types import PosetName
        >>>
        >>> # Initialize voter with a poset containing only incomparable elements
        >>> initial_poset = Poset(
        ...     name=PosetName("Team Priorities"),
        ...     description=Description("Building team consensus"),
        ...     posetspace=project_space,
        ...     relations=[]  # No initial ordering
        ... )
        >>>
        >>> voter = Voter(poset=initial_poset)
        >>>
        >>> # Start voting process (when implemented)
        >>> # first_antichain = voter.next_antichain(None)  # Get first comparison
        >>> # Present to user: "Compare Security Update with UI Redesign"
        >>> # User votes...
        >>> # voted = VotedAntichain(antichain=first_antichain, ...)
        >>> # next_antichain = voter.next_antichain(voted)  # Get next comparison
        >>> # Continue until a complete Poset is returned
    """

    poset: Poset

    def next_antichain(self, voted_antichain: VotedAntichain) -> Antichain | Poset:
        """Determine the next antichain to vote on given a voted antichain.

        This method implements the core voting algorithm that decides which
        comparisons to present next based on previous voting results. The algorithm
        aims to efficiently construct a complete poset ordering through minimal
        user interactions.

        Args:
            voted_antichain: The result of the previous voting round, containing
                           the resolved comparisons.

        Returns:
            Either:
            - Antichain: The next set of comparisons to present to the user
            - Poset: The final poset if voting is complete

        Raises:
            NotImplementedError: Voting algorithm is not yet implemented.

        Examples:
            >>> # Interactive voting session (conceptual example)
            >>> voter = Voter(poset=initial_poset)
            >>>
            >>> # First round of voting
            >>> antichain1 = Antichain(element=feature_a, comparisons={feature_b, feature_c})
            >>> voted1 = VotedAntichain(
            ...     antichain=antichain1,
            ...     new_less={feature_b},
            ...     new_greater={feature_c}
            ... )
            >>>
            >>> # Get next comparison based on previous vote
            >>> result = voter.next_antichain(voted1)
            >>>
            >>> if isinstance(result, Antichain):
            ...     print(f"Compare {result.element.name} with:")
            ...     for elem in result.comparisons:
            ...         print(f"  - {elem.name}")
            ... else:
            ...     # result is a Poset - voting complete
            ...     print(f"Final ordering has {len(result.relations)} relations")
            ...     for rel in result.relations:
            ...         print(f"{rel.less.name} < {rel.greater.name}")

        Note:
            Future implementations may use various strategies such as:
            - Topological sorting to minimize comparisons
            - Adaptive algorithms that learn from voting patterns
            - Heuristics based on element properties
        """
        # Skeleton implementation
        raise NotImplementedError("Voting algorithm not yet implemented")
