from __future__ import annotations

from dataclasses import dataclass, field
from pathlib import Path


@dataclass(slots=True)
class SessionHistory:
    """In-memory session history for visited directories."""

    _entries: list[Path] = field(default_factory=list)
    _index: int = -1

    def visit(self, path: Path) -> Path:
        """Record a directory visit and discard forward history when needed."""

        resolved_path = path.expanduser().resolve()

        if self.current == resolved_path:
            return resolved_path

        if self._index < len(self._entries) - 1:
            self._entries = self._entries[: self._index + 1]

        self._entries.append(resolved_path)
        self._index = len(self._entries) - 1
        return resolved_path

    @property
    def current(self) -> Path | None:
        """Return the current history entry."""

        if self._index == -1:
            return None

        return self._entries[self._index]

    def back(self) -> Path | None:
        """Move backward in history when possible."""

        if self._index <= 0:
            return None

        self._index -= 1
        return self._entries[self._index]

    def forward(self) -> Path | None:
        """Move forward in history when possible."""

        if self._index == -1 or self._index >= len(self._entries) - 1:
            return None

        self._index += 1
        return self._entries[self._index]

    def select(self, index: int) -> Path:
        """Jump to a previously visited directory by history index."""

        if index < 0 or index >= len(self._entries):
            raise IndexError("History index out of range")

        self._index = index
        return self._entries[self._index]

    def entries(self) -> tuple[Path, ...]:
        """Return the full history as an immutable sequence."""

        return tuple(self._entries)