"""
Strands @tool functions for agents to read/write OpenSearch agentic memory.
These tools are shared across the Query Understanding and Ranking agents.
"""

import json
import os
from typing import Optional
from strands import tool

from search_personalization.agentic_memory.config import CONTAINER_ID
from search_personalization.agentic_memory.memory_client import read_memory, write_memory

# In-memory cache for rerank results (keyed by hash of query + documents)
_rerank_cache: dict[str, str] = {}


def _get_container_id() -> str:
    """Get the single memory container ID, raising if not configured."""
    if not CONTAINER_ID:
        raise ValueError(
            "MEMORY_CONTAINER_ID not configured. Run setup or set the env var."
        )
    return CONTAINER_ID


@tool
def get_user_profile(persona_id: str) -> str:
    """Retrieve the user's long-term memory profile from OpenSearch agentic memory.
    Returns extracted preferences including color preferences, style, size, price sensitivity,
    and any explicit aversions learned from purchase history, returns, and reviews.

    Args:
        persona_id: The user ID (e.g., user1, user2).
    """
    from search_personalization.agentic_memory.memory_client import _client

    container_id = _get_container_id()
    namespace = {"user_id": persona_id}

    # Query long-term memory filtered to USER_PREFERENCE strategy only
    client = _client()
    body = {
        "query": {"bool": {"must": [
            {"term": {"namespace.user_id": persona_id}},
            {"term": {"strategy_type": "USER_PREFERENCE"}},
        ]}},
        "size": 20,
    }
    result = client.transport.perform_request(
        "GET",
        f"/_plugins/_ml/memory_containers/{container_id}/memories/long-term/_search",
        body=body,
    )

    memories = result.get("hits", {}).get("hits", [])
    trace = {
        "memory_reads": [
            {
                "namespace": namespace,
                "type": "long-term",
                "strategy_filter": "USER_PREFERENCE",
                "records_retrieved": len(memories),
            }
        ]
    }

    return json.dumps(
        {"persona_id": persona_id, "memories": memories, "trace": trace},
        indent=2,
        default=str,
    )


@tool
def read_session_memory(persona_id: str, session_id: str) -> str:
    """Retrieve current session context for multi-turn query understanding.
    Returns previous queries and interactions within this shopping session.

    Args:
        persona_id: The user ID (e.g., user1, user2).
        session_id: The current session identifier.
    """
    container_id = _get_container_id()
    namespace = {"user_id": persona_id, "session_id": session_id}

    result = read_memory(
        container_id=container_id,
        namespace=namespace,
        memory_type="sessions",
    )

    memories = result.get("hits", {}).get("hits", [])
    trace = {
        "memory_reads": [
            {
                "namespace": namespace,
                "type": "session",
                "records_retrieved": len(memories),
            }
        ]
    }

    return json.dumps(
        {"persona_id": persona_id, "session_id": session_id, "memories": memories, "trace": trace},
        indent=2,
        default=str,
    )


@tool
def write_session_memory(persona_id: str, session_id: str, content: str) -> str:
    """Write a conversation turn to session memory for multi-turn context.

    Args:
        persona_id: The user ID.
        session_id: The current session identifier.
        content: The conversation turn content to store (query + results summary).
    """
    container_id = _get_container_id()
    namespace = {"user_id": persona_id, "session_id": session_id}

    result = write_memory(
        container_id=container_id,
        namespace=namespace,
        content=content,
    )

    trace = {
        "memory_writes": [
            {
                "namespace": namespace,
                "type": "session",
                "action": "write_session_turn",
            }
        ]
    }

    return json.dumps({"status": "written", "trace": trace}, indent=2, default=str)


@tool
def write_working_memory(persona_id: str, session_id: str, enriched_query: str) -> str:
    """Write the enriched query decomposition to working memory for the Ranking Agent to consume.
    This is the inter-agent communication channel.

    Args:
        persona_id: The user ID.
        session_id: The current session identifier.
        enriched_query: JSON string containing the enriched, decomposed query with all inferred attributes.
    """
    container_id = _get_container_id()
    namespace = {"user_id": persona_id, "session_id": session_id}

    result = write_memory(
        container_id=container_id,
        namespace=namespace,
        content=enriched_query,
        infer=False,
    )

    trace = {
        "memory_writes": [
            {
                "namespace": namespace,
                "type": "working-memory",
                "action": "write_enriched_query",
            }
        ]
    }

    return json.dumps({"status": "written", "trace": trace}, indent=2, default=str)


@tool
def write_history(persona_id: str, session_id: str, content: str) -> str:
    """Append a completed interaction to the user's history for long-term pattern learning.

    Args:
        persona_id: The user ID.
        session_id: The session identifier.
        content: Summary of the completed interaction (query, enrichment, results, outcome).
    """
    container_id = _get_container_id()
    namespace = {"user_id": persona_id, "session_id": session_id}

    result = write_memory(
        container_id=container_id,
        namespace=namespace,
        content=content,
    )

    trace = {
        "memory_writes": [
            {
                "namespace": namespace,
                "type": "history",
                "action": "append_interaction",
            }
        ]
    }

    return json.dumps({"status": "written", "trace": trace}, indent=2, default=str)


@tool
def search_product_catalog(query: str, category: Optional[str] = None, max_price: Optional[float] = None, gender_affinity: Optional[str] = None, size: int = 10) -> str:
    """Search the product catalog using server-side neural query (OpenSearch does the embedding).
    Style/product-type matching is handled semantically by the vector search — do NOT use term filters
    for fields with semantic meaning.

    Only truly categorical/numeric fields are used as hard filters:
    - category: broad taxonomy (5 values) — safe for exact filtering
    - max_price: numeric range — safe for range filtering
    - gender_affinity: hard filter ("M" or "F") to ensure persona-appropriate results

    Args:
        query: Natural language search query (e.g., "navy leather boots").
        category: Optional category filter (apparel, footwear, accessories, jewelry, electronics).
        max_price: Optional maximum price filter.
        gender_affinity: Optional gender affinity filter ("M" or "F"). Hard-filters to persona-appropriate products.
        size: Max number of results to return.
    """
    import os
    from search_personalization.data_loader import get_opensearch_client

    client = get_opensearch_client()
    model_id = os.getenv('OPENSEARCH_MODEL_ID', 'default_model_id')

    # Hard filters: only for truly categorical/numeric fields
    filter_clauses = []
    if category:
        filter_clauses.append({"term": {"category": category}})
    if max_price:
        filter_clauses.append({"range": {"price": {"lte": max_price}}})
    if gender_affinity:
        filter_clauses.append({"term": {"gender_affinity": gender_affinity.upper()}})

    # Use server-side neural query — OpenSearch calls the embedding model via its ML connector
    neural_query: dict = {
        "neural": {
            "product_description_vector": {
                "query_text": query,
                "model_id": model_id,
                "k": size,
            }
        }
    }

    if filter_clauses:
        # Use neural query's built-in filter (pre-filter before kNN neighbor selection)
        neural_query["neural"]["product_description_vector"]["filter"] = {"bool": {"filter": filter_clauses}}

    query_body = {
        "size": size,
        "query": neural_query,
    }

    resp = client.search(index="products", body=query_body)
    hits = resp["hits"]["hits"]

    results = []
    for h in hits:
        src = h["_source"]
        results.append({
            "id": src.get("id"),
            "name": src.get("name"),
            "category": src.get("category"),
            "style": src.get("style"),
            "price": src.get("price"),
            "description": src.get("description", "")[:150],
            "score": h.get("_score"),
        })

    return json.dumps({"total_hits": resp["hits"]["total"]["value"], "results": results, "_opensearch_query": query_body}, indent=2, default=str)


@tool
def rerank_results(query: str, documents: str, top_n: int = 10) -> str:
    """Rerank search results using Cohere Rerank 3.5 via Bedrock.
    Call this AFTER search_product_catalog to reorder results by relevance
    to the enriched query. Pass the enriched query (with user preferences baked in)
    as the query parameter for personalized reranking.

    Args:
        query: The enriched query string to rerank against (e.g., "spacious tan leather backpack, neutral colors, business-casual, $75-$175").
        documents: JSON string — either the full search_product_catalog output or just the results array.
        top_n: Number of top results to return after reranking.
    """
    import hashlib
    import boto3

    # Cache lookup — keyed by query + document content
    cache_key = hashlib.sha256((query + documents if isinstance(documents, str) else query + json.dumps(documents, sort_keys=True)).encode()).hexdigest()
    if cache_key in _rerank_cache:
        return _rerank_cache[cache_key]

    client = boto3.client("bedrock-runtime", region_name=os.getenv("AWS_REGION", "us-east-1"))

    # Robustly parse documents — handle both full output and just the array
    if isinstance(documents, str):
        parsed = json.loads(documents)
    else:
        parsed = documents

    if isinstance(parsed, dict) and "results" in parsed:
        docs = parsed["results"]
    elif isinstance(parsed, list):
        docs = parsed
    else:
        docs = parsed.get("reranked_results", []) if isinstance(parsed, dict) else []

    if not docs:
        return json.dumps({"error": "No documents to rerank"})

    # Build document strings for Cohere Rerank API (must be plain strings)
    doc_texts = []
    for d in docs:
        text = f"{d.get('name', '')}. {d.get('description', '')}. Style: {d.get('style', '')}. Category: {d.get('category', '')}. Price: ${d.get('price', '')}"
        doc_texts.append(text)

    body = json.dumps({
        "query": query,
        "documents": doc_texts,
        "top_n": min(top_n, len(doc_texts)),
        "api_version": 2,
    })

    response = client.invoke_model(
        modelId="cohere.rerank-v3-5:0",
        body=body,
        contentType="application/json",
        accept="application/json",
    )

    result = json.loads(response["body"].read())
    reranked = []
    for item in result.get("results", []):
        idx = item["index"]
        if idx < len(docs):
            original = docs[idx].copy()
            original["rerank_score"] = item["relevance_score"]
            reranked.append(original)

    result_json = json.dumps({"reranked_results": reranked}, indent=2, default=str)
    _rerank_cache[cache_key] = result_json
    return result_json