"""
SessionContext — binds field, vault, vocab, and persona for one session.

One session = one field trajectory on the manifold.
The vault accumulates versors across turns.
The persona motor is fixed per session (or composable across sessions).

Generation returns GenerationResult so the evolved field state is preserved.
The assistant vault entry stores the generated final_state, not the prompt
field that entered the turn.
"""

from __future__ import annotations

import numpy as np

from algebra.backend import versor_apply
from algebra.cga import cga_inner, outer_product
from field.state import FieldState
from generate.dialogue import DialogueTurn
from generate.proposition import Proposition
from generate.result import GenerationResult
from generate.stream import generate
from ingest.gate import inject
from persona.motor import PersonaMotor
from vault.store import VaultStore


class SessionContext:
    def __init__(self, vocab, persona=None, vault=None, vault_reproject_interval: int = 100):
        self.vocab = vocab
        self.persona = persona or PersonaMotor.identity()
        self.vault = vault or VaultStore(reproject_interval=vault_reproject_interval)
        self.state: FieldState | None = None
        self.turn: int = 0
        self.dialogue_history: list[DialogueTurn] = []
        self.running_dialogue_blade: np.ndarray | None = None
        self._last_response_tokens: tuple[str, ...] | None = None
        self._anchor_field: np.ndarray | None = None

    def ingest(self, tokens: list) -> FieldState:
        """Inject a prompt into the running field. Stores the user field in vault."""
        injected = inject(tokens, self.vocab)
        node_idx = self.vocab.index_of(tokens[0])
        if self.state is None:
            self.state = FieldState(
                F=injected.F,
                node=node_idx,
                step=injected.step,
                holonomy=injected.holonomy,
                energy=injected.energy,
                valence=injected.valence,
            )
            self._anchor_field = self.state.F.copy()
        else:
            self.state = FieldState(
                F=versor_apply(injected.F, self.state.F),
                node=node_idx,
                step=self.state.step + 1,
                holonomy=injected.holonomy,
                energy=injected.energy,
                valence=injected.valence,
            )
        self.vault.store(self.state.F, {"turn": self.turn, "role": "user"})
        return self.state

    def record_dialogue(self, proposition: Proposition) -> DialogueTurn:
        """
        Store a proposition as geometric dialogue state.

        The transcript surface is deliberately not used as session memory here;
        the retained object is the proposition paired with its relation blade.
        """
        blade = proposition.relation
        turn = DialogueTurn(proposition=proposition, outer_product_blade=blade)
        self.dialogue_history.append(turn)
        if self.running_dialogue_blade is None:
            self.running_dialogue_blade = blade.copy()
        else:
            self.running_dialogue_blade = outer_product(self.running_dialogue_blade, blade)
        return turn

    @property
    def last_dialogue_blade(self) -> np.ndarray | None:
        if not self.dialogue_history:
            return None
        return self.dialogue_history[-1].outer_product_blade.copy()

    def respond(self, max_tokens: int = 128) -> GenerationResult:
        """
        Generate a response from current state and preserve the evolved field.

        Returns:
            GenerationResult carrying emitted tokens and final_state.
        """
        assert self.state is not None, "Call ingest() before respond()."
        result = generate(self.state, self.vocab, self.persona, max_tokens, vault=self.vault)
        if self._last_response_tokens is not None and result.tokens == self._last_response_tokens and result.tokens:
            try:
                pivot_node = self.vocab.index_of(result.tokens[0])
            except KeyError:
                pivot_node = self.state.node
            if pivot_node != self.state.node:
                pivot = FieldState(
                    F=self.state.F,
                    node=pivot_node,
                    step=self.state.step,
                    holonomy=self.state.holonomy,
                    energy=self.state.energy,
                    valence=self.state.valence,
                )
                result = generate(pivot, self.vocab, self.persona, max_tokens, vault=self.vault)
        final_state = result.final_state
        coherence_anchor = self._anchor_field if self._anchor_field is not None else self.state.F
        if cga_inner(final_state.F, coherence_anchor) < 0.0:
            final_state = FieldState(
                F=-final_state.F,
                node=final_state.node,
                step=final_state.step,
                holonomy=final_state.holonomy,
                energy=final_state.energy,
                valence=final_state.valence,
            )
            result = GenerationResult(
                tokens=result.tokens,
                final_state=final_state,
                trajectory=result.trajectory,
                salience_top_k=result.salience_top_k,
                candidates_used=result.candidates_used,
            )
        self.state = result.final_state
        self.vault.store(result.final_state.F, {"turn": self.turn, "role": "assistant"})
        self.turn += 1
        self._last_response_tokens = result.tokens
        return result

    async def arespond(self, max_tokens: int = 128):
        """
        Async token-yielding response path.

        The generation pass still returns a GenerationResult internally so
        SessionContext can store the evolved assistant final_state after
        yielding the surface tokens.
        """
        assert self.state is not None, "Call ingest() before arespond()."
        result = generate(self.state, self.vocab, self.persona, max_tokens, vault=self.vault)
        for token in result.tokens:
            yield token
        self.state = result.final_state
        self.vault.store(result.final_state.F, {"turn": self.turn, "role": "assistant"})
        self.turn += 1

    def recall(self, query_tokens: list, top_k: int = 5) -> list:
        """Recall relevant past versors for a query."""
        query_state = inject(query_tokens, self.vocab)
        return self.vault.recall(query_state.F, top_k=top_k)