"""
Stage 4: Query Language and Steering Interface

Provides a formal query language for navigating the program space by composing
concepts. Users express preferences as concept coordinates, and the system
steers LLM generation accordingly.

The query language supports:
  - Single concept selection: steer("recursive", strength=0.8)
  - Concept composition: steer(recursive=0.8, space_efficient=0.6)
  - Concept negation: steer(mutation=-0.5)  (avoid mutation)
  - Region queries: select(region_where(recursive > 0.5, fast_execution > 0.7))
  - Lattice navigation: refine(current, add_concept="memoization")
"""

from __future__ import annotations

import logging
import re
from dataclasses import dataclass, field
from typing import Any, Optional, Union

import numpy as np

from reason_first_program.program_space import Program, ProgramSpace
from reason_first_program.concepts import Concept, ConceptSet
from reason_first_program.embeddings import (
    ConceptEmbeddingSpace,
    GCAVEmbedding,
    MSRSSteering,
)

logger = logging.getLogger(__name__)


@dataclass
class ConceptQuery:
    """
    A query in the concept space.
    
    A query is a weighted combination of concepts that defines a target
    region in the program space. The system either:
      1. Selects existing programs nearest to this region, or
      2. Steers generation toward this region.
    
    Formally: q = Σ_i w_i · v_i where v_i is concept i's activation vector
    """

    weights: dict[str, float] = field(default_factory=dict)
    constraints: dict[str, tuple[str, float]] = field(default_factory=dict)
    # constraints: {concept_name: (operator, threshold)} e.g., {"recursive": (">", 0.5)}
    metadata: dict[str, Any] = field(default_factory=dict)

    def __repr__(self) -> str:
        parts = []
        for name, weight in sorted(self.weights.items(), key=lambda x: -abs(x[1])):
            if weight > 0:
                parts.append(f"+{weight:.1f}·{name}")
            else:
                parts.append(f"{weight:.1f}·{name}")
        for name, (op, val) in self.constraints.items():
            parts.append(f"{name}{op}{val:.1f}")
        return f"Query({', '.join(parts)})"

    @property
    def concept_vector(self) -> dict[str, float]:
        """The query as a concept-space direction vector."""
        return self.weights.copy()

    def matches(self, concept_scores: dict[str, float]) -> bool:
        """Check if a program's concept scores satisfy the query constraints."""
        for name, (op, threshold) in self.constraints.items():
            score = concept_scores.get(name, 0.0)
            if op == ">" and not (score > threshold):
                return False
            elif op == ">=" and not (score >= threshold):
                return False
            elif op == "<" and not (score < threshold):
                return False
            elif op == "<=" and not (score <= threshold):
                return False
            elif op == "==" and not (abs(score - threshold) < 0.05):
                return False
        return True

    def distance_to(self, concept_scores: dict[str, float]) -> float:
        """
        Compute distance from a program's concept scores to this query.
        Lower = more aligned with query.
        """
        total = 0.0
        for name, target_weight in self.weights.items():
            actual = concept_scores.get(name, 0.0)
            # Distance weighted by how strongly we care about this concept
            total += abs(target_weight) * (actual - (1.0 if target_weight > 0 else 0.0)) ** 2
        return total


class QueryLanguage:
    """
    Parser and builder for concept queries.
    
    Supports a simple DSL:
      "recursive > 0.5 AND fast_execution > 0.7"
      "recursive=0.8, space_efficient=0.6, mutation=-0.3"
      "LIKE program_id_abc123"  (find programs similar to a reference)
      "NOT mutation"  (avoid mutation)
    """

    def __init__(self, concept_set: ConceptSet):
        self.concept_set = concept_set

    def parse(self, query_str: str) -> ConceptQuery:
        """Parse a query string into a ConceptQuery."""
        query = ConceptQuery()

        # Handle comma-separated weight assignments: "recursive=0.8, mutation=-0.3"
        weight_pattern = r"(\w+)\s*=\s*(-?\d+\.?\d*)"
        for match in re.finditer(weight_pattern, query_str):
            name = match.group(1)
            weight = float(match.group(2))
            if self.concept_set.get_by_name(name):
                query.weights[name] = weight

        # Handle constraint expressions: "recursive > 0.5"
        constraint_pattern = r"(\w+)\s*(>=|<=|>|<|==)\s*(-?\d+\.?\d*)"
        for match in re.finditer(constraint_pattern, query_str):
            name = match.group(1)
            op = match.group(2)
            threshold = float(match.group(3))
            if name not in query.weights:  # Don't double-count
                if self.concept_set.get_by_name(name):
                    query.constraints[name] = (op, threshold)

        # Handle NOT: "NOT mutation"
        not_pattern = r"NOT\s+(\w+)"
        for match in re.finditer(not_pattern, query_str, re.IGNORECASE):
            name = match.group(1)
            if self.concept_set.get_by_name(name):
                query.weights[name] = query.weights.get(name, -1.0)

        return query

    def build(self, **concept_weights: float) -> ConceptQuery:
        """Build a query from keyword arguments."""
        validated = {}
        for name, weight in concept_weights.items():
            if self.concept_set.get_by_name(name):
                validated[name] = weight
            else:
                logger.warning(f"Unknown concept: {name}")
        return ConceptQuery(weights=validated)

    def constrain(self, **constraints: str) -> ConceptQuery:
        """
        Build a constraint query.
        Example: constrain(recursive=">0.5", fast_execution=">=0.7")
        """
        query = ConceptQuery()
        for name, expr in constraints.items():
            if not self.concept_set.get_by_name(name):
                logger.warning(f"Unknown concept: {name}")
                continue
            match = re.match(r"(>=|<=|>|<|==)?\s*(-?\d+\.?\d*)", expr)
            if match:
                op = match.group(1) or ">"
                threshold = float(match.group(2))
                query.constraints[name] = (op, threshold)
        return query


class SteeringEngine:
    """
    Engine for steering program generation using concept queries.
    
    Two modes:
      1. Selection: Given a ProgramSpace and a query, rank/filter programs
      2. Generation: Given a query, steer LLM hidden states during generation
    
    Selection uses concept scores directly.
    Generation uses GCAV vectors (e' = e + ε·v) or MSRS orthogonal steering.
    """

    def __init__(
        self,
        concept_set: ConceptSet,
        embedding_space: Optional[ConceptEmbeddingSpace] = None,
        gcav: Optional[GCAVEmbedding] = None,
        msrs: Optional[MSRSSteering] = None,
    ):
        self.concept_set = concept_set
        self.embedding_space = embedding_space
        self.gcav = gcav
        self.msrs = msrs
        self.query_language = QueryLanguage(concept_set)

    # ---- Selection Mode ----

    def select(
        self,
        space: ProgramSpace,
        query: Union[ConceptQuery, str],
        top_k: int = 10,
    ) -> list[tuple[Program, float]]:
        """
        Select programs from the space that best match the query.
        
        Returns list of (program, relevance_score) tuples, sorted by relevance.
        """
        if isinstance(query, str):
            query = self.query_language.parse(query)

        scored: list[tuple[Program, float]] = []

        for program in space.valid_programs:
            concept_scores = self.concept_set.score_program(program)

            # Check hard constraints
            if not query.matches(concept_scores):
                continue

            # Compute soft relevance score
            relevance = self._compute_relevance(concept_scores, query)
            scored.append((program, relevance))

        # Sort by relevance (higher = better match)
        scored.sort(key=lambda x: x[1], reverse=True)
        return scored[:top_k]

    def _compute_relevance(
        self,
        concept_scores: dict[str, float],
        query: ConceptQuery,
    ) -> float:
        """
        Compute relevance of a program to a query.
        
        For positive weights: reward high concept scores
        For negative weights: reward low concept scores
        """
        relevance = 0.0
        total_weight = 0.0

        for name, target_weight in query.weights.items():
            actual = concept_scores.get(name, 0.0)
            if target_weight > 0:
                relevance += target_weight * actual
            else:
                relevance += abs(target_weight) * (1.0 - actual)
            total_weight += abs(target_weight)

        if total_weight > 0:
            relevance /= total_weight

        return relevance

    def filter(
        self,
        space: ProgramSpace,
        query: Union[ConceptQuery, str],
    ) -> ProgramSpace:
        """Filter a ProgramSpace to programs matching the query."""
        if isinstance(query, str):
            query = self.query_language.parse(query)

        filtered = ProgramSpace(space.stub)
        for program in space.valid_programs:
            concept_scores = self.concept_set.score_program(program)
            if query.matches(concept_scores):
                filtered.add(program)
        return filtered

    # ---- Generation Steering Mode ----

    def build_steering_vector(
        self,
        query: Union[ConceptQuery, str],
        method: str = "additive",
    ) -> Optional[np.ndarray]:
        """
        Build a steering vector from a concept query.
        
        Args:
            query: The concept query
            method: 'additive' (GCAV sum) or 'msrs' (orthogonal subspaces)
            
        Returns:
            Steering vector in activation space, or None if no GCAV available
        """
        if isinstance(query, str):
            query = self.query_language.parse(query)

        if method == "additive" and self.gcav is not None:
            # Simple additive: v_steer = Σ w_i · v_i
            steer = np.zeros_like(
                next(iter(self.gcav.concept_vectors.values()))
            )
            for name, weight in query.weights.items():
                if name in self.gcav.concept_vectors:
                    steer += weight * self.gcav.concept_vectors[name]
            return steer

        elif method == "msrs" and self.msrs is not None:
            # Use MSRS orthogonal steering
            base = np.zeros(self.msrs.S_align.shape[1])
            return self.msrs.steer(base, query.weights) - base

        return None

    def steer_prompt(
        self,
        query: Union[ConceptQuery, str],
        base_prompt: str,
    ) -> str:
        """
        Augment a generation prompt with concept-steering instructions.
        
        This is a lightweight steering approach that works with any LLM API
        (no hidden state access needed). For stronger steering, use
        build_steering_vector with activation-level intervention.
        """
        if isinstance(query, str):
            query = self.query_language.parse(query)

        concept_instructions = []
        for name, weight in sorted(
            query.weights.items(), key=lambda x: -abs(x[1])
        ):
            concept = self.concept_set.get_by_name(name)
            if concept is None:
                continue

            if weight > 0.5:
                concept_instructions.append(
                    f"STRONGLY PREFER: {concept.description}"
                )
            elif weight > 0:
                concept_instructions.append(
                    f"PREFER: {concept.description}"
                )
            elif weight < -0.5:
                concept_instructions.append(
                    f"STRONGLY AVOID: {concept.description}"
                )
            elif weight < 0:
                concept_instructions.append(
                    f"AVOID: {concept.description}"
                )

        for name, (op, threshold) in query.constraints.items():
            concept = self.concept_set.get_by_name(name)
            if concept:
                concept_instructions.append(
                    f"CONSTRAINT: {concept.description} ({op} {threshold})"
                )

        if not concept_instructions:
            return base_prompt

        steering_block = "\n".join(
            f"  - {inst}" for inst in concept_instructions
        )
        return (
            f"{base_prompt}\n\n"
            f"CONCEPT STEERING INSTRUCTIONS:\n{steering_block}\n\n"
            f"Follow the above concept preferences when implementing."
        )

    # ---- Exploration Mode ----

    def explore_neighbors(
        self,
        program: Program,
        space: ProgramSpace,
        n_neighbors: int = 5,
    ) -> list[tuple[Program, float, dict[str, float]]]:
        """
        Find programs in the space that are conceptually nearby.
        
        Returns list of (program, distance, concept_diff) tuples.
        concept_diff shows which concepts differ most.
        """
        ref_scores = self.concept_set.score_program(program)

        neighbors: list[tuple[Program, float, dict[str, float]]] = []
        for other in space.valid_programs:
            if other.program_id == program.program_id:
                continue

            other_scores = self.concept_set.score_program(other)

            # Euclidean distance in concept space
            diff = {}
            dist_sq = 0.0
            for name in set(ref_scores) | set(other_scores):
                d = ref_scores.get(name, 0.0) - other_scores.get(name, 0.0)
                if abs(d) > 0.01:
                    diff[name] = d
                dist_sq += d ** 2

            neighbors.append((other, dist_sq ** 0.5, diff))

        neighbors.sort(key=lambda x: x[1])
        return neighbors[:n_neighbors]

    def concept_boundary_programs(
        self,
        concept_name: str,
        space: ProgramSpace,
        n_per_side: int = 3,
    ) -> dict[str, list[Program]]:
        """
        Find programs at the boundary of a concept.
        Returns programs just inside and just outside the concept region.
        """
        concept = self.concept_set.get_by_name(concept_name)
        if concept is None:
            return {"inside": [], "outside": []}

        inside: list[tuple[Program, float]] = []
        outside: list[tuple[Program, float]] = []

        for program in space.valid_programs:
            score = concept.score(program)
            if score > 0.5:
                inside.append((program, score))
            else:
                outside.append((program, score))

        # Sort inside by score ascending (closest to boundary)
        inside.sort(key=lambda x: x[1])
        # Sort outside by score descending (closest to boundary)
        outside.sort(key=lambda x: x[1], reverse=True)

        return {
            "inside": [p for p, _ in inside[:n_per_side]],
            "outside": [p for p, _ in outside[:n_per_side]],
        }