import asyncio
import os
from contextlib import asynccontextmanager
from typing import Optional

import asyncpg
import psycopg2
from cachetools import TTLCache, cached
from dotenv import load_dotenv
import pandas as pd

# Global connection pool
load_dotenv()


@asynccontextmanager
async def get_async_connection(schema="talmudexplore"):
    """Get a connection for the current request."""
    conn = None
    try:
        # Create a single connection without relying on a shared pool
        conn = await asyncpg.connect(
            database=os.getenv("pg_dbname"),
            user=os.getenv("pg_user"),
            password=os.getenv("pg_password"),
            host=os.getenv("pg_host"),
            port=os.getenv("pg_port")
        )
        await conn.execute(f'SET search_path TO {schema}')
        yield conn
    finally:
        if conn:
            await conn.close()


async def get_questions(conn: asyncpg.Connection):
    questions = await conn.fetch("SELECT id, question_text FROM questions where question_group_id = 1 ORDER BY id")
    return [{"id": q["id"], "text": q["question_text"]} for q in questions]

@cached(cache=TTLCache(ttl=1800, maxsize=1024))
async def get_metadata(conn: asyncpg.Connection, question_id: int, source_finder_id_run_id: int):
    metadata = await conn.fetchrow('''
        SELECT metadata 
        FROM source_finder_run_question_metadata sfrqm                           
        WHERE sfrqm.question_id = $1 and sfrqm.source_finder_run_id = $2;
    ''', question_id, source_finder_id_run_id)
    if metadata is None:
        return ""
    return metadata.get('metadata')


# Get distinct source finders
async def get_source_finders(conn: asyncpg.Connection):
    finders = await conn.fetch("""
        SELECT distinct sf.id, sf.source_finder_type as name from talmudexplore.source_finder_runs sfr
        join talmudexplore.source_finders sf on sf.id = sfr.source_finder_id
        WHERE EXISTS (
            SELECT 1
            FROM talmudexplore.source_run_results srr
            WHERE srr.source_finder_run_id = sfr.id
        )
    ORDER BY sf.id
    """
    )
    return [{"id": f["id"], "name": f["name"]} for f in finders]


# Get distinct run IDs for a question
@cached(cache=TTLCache(ttl=1800, maxsize=1024))
async def get_run_ids(conn: asyncpg.Connection, source_finder_id: int, question_id: int = None):
    query = """
    select distinct sfr.description, srs.source_finder_run_id as run_id
        from source_run_results srs
        join source_finder_runs sfr on srs.source_finder_run_id = sfr.id
        join source_finders sf on sfr.source_finder_id = sf.id
        where sfr.source_finder_id = $1        
    """

    if question_id is not None:
        query += " and srs.question_id = $2"
        params = (source_finder_id, question_id)
    else:
        params = (source_finder_id,)
    query += " order by run_id DESC;"

    run_ids = await conn.fetch(query, *params)
    return {r["description"]:r["run_id"] for r in run_ids}


async def get_baseline_rankers(conn: asyncpg.Connection):
    query = """
    SELECT sfr.id, sf.source_finder_type, sfr.description from source_finder_runs sfr
    join source_finders sf on sf.id = sfr.source_finder_id
    WHERE EXISTS (
        SELECT 1
        FROM source_run_results srr
        WHERE srr.source_finder_run_id = sfr.id
    )
    ORDER BY sf.id
    """

    rankers = await conn.fetch(query)
    return [{"id": r["id"], "name": f"{r['source_finder_type']} : {r['description']}"} for r in rankers]

async def calculate_baseline_vs_source_stats_for_question(conn: asyncpg.Connection, baseline_sources , source_runs_sources):
    # for a given question_id and source_finder_id and run_id calculate the baseline vs source stats
    # e.g. overlap, high ranked overlap, etc.

    actual_sources_set = {s["id"] for s in source_runs_sources}
    baseline_sources_set = {s["id"] for s in baseline_sources}

    # Calculate overlap
    overlap = actual_sources_set.intersection(baseline_sources_set)
    # only_in_1 = actual_sources_set - baseline_sources_set
    # only_in_2 = baseline_sources_set - actual_sources_set

    # Calculate high-ranked overlap (rank >= 4)
    actual_high_ranked = {s["id"] for s in source_runs_sources if int(s["source_rank"]) >= 4}
    baseline_high_ranked = {s["id"] for s in baseline_sources if int(s["baseline_rank"]) >= 4}

    high_ranked_overlap = actual_high_ranked.intersection(baseline_high_ranked)

    results = {
        "total_baseline_sources": len(baseline_sources),
        "total_found_sources": len(source_runs_sources),
        "overlap_count": len(overlap),
        "overlap_percentage": round(len(overlap) * 100 / max(len(actual_sources_set), len(baseline_sources_set)),
                                    2) if max(len(actual_sources_set), len(baseline_sources_set)) > 0 else 0,
        "num_high_ranked_baseline_sources": len(baseline_high_ranked),
        "num_high_ranked_found_sources": len(actual_high_ranked),
        "high_ranked_overlap_count": len(high_ranked_overlap),
        "high_ranked_overlap_percentage": round(len(high_ranked_overlap) * 100 / max(len(actual_high_ranked), len(baseline_high_ranked)), 2) if max(len(actual_high_ranked), len(baseline_high_ranked)) > 0 else 0
    }
    #convert results to dataframe
    results_df = pd.DataFrame([results])
    return results_df


async def calculate_cumulative_statistics_for_all_questions(conn: asyncpg.Connection, source_finder_run_id: int, ranker_id: int):
    """
    Calculate cumulative statistics across all questions for a specific source finder, run, and ranker.

    Args:
        source_finder_run_id (int): ID of the source finder and run as appears in source runs
        ranker_id (int): ID of the baseline ranker

    Returns:
        pd.DataFrame: DataFrame containing aggregated statistics
    """
    # Get all questions
    query = "SELECT id FROM questions ORDER BY id"
    questions = await conn.fetch(query)
    question_ids = [q["id"] for q in questions]

    # Initialize aggregates
    total_baseline_sources = 0
    total_found_sources = 0
    total_overlap = 0
    total_high_ranked_baseline = 0
    total_high_ranked_found = 0
    total_high_ranked_overlap = 0

    # Process each question
    valid_questions = 0
    for question_id in question_ids:
        try:
            # Get unified sources for this question
            sources, stats = await get_unified_sources(conn, question_id, source_finder_run_id, ranker_id)

            if sources and len(sources) > 0:
                valid_questions += 1
                stats_dict = stats.iloc[0].to_dict()

                # Add to running totals
                total_baseline_sources += stats_dict.get('total_baseline_sources', 0)
                total_found_sources += stats_dict.get('total_found_sources', 0)
                total_overlap += stats_dict.get('overlap_count', 0)
                total_high_ranked_baseline += stats_dict.get('num_high_ranked_baseline_sources', 0)
                total_high_ranked_found += stats_dict.get('num_high_ranked_found_sources', 0)
                total_high_ranked_overlap += stats_dict.get('high_ranked_overlap_count', 0)
        except Exception as e:
            # Skip questions with errors
            continue

    # Calculate overall percentages
    overlap_percentage = round(total_overlap * 100 / max(total_baseline_sources, total_found_sources), 2) \
        if max(total_baseline_sources, total_found_sources) > 0 else 0

    high_ranked_overlap_percentage = round(
        total_high_ranked_overlap * 100 / max(total_high_ranked_baseline, total_high_ranked_found), 2) \
        if max(total_high_ranked_baseline, total_high_ranked_found) > 0 else 0

    # Compile results
    cumulative_stats = {
        "total_questions_analyzed": valid_questions,
        "total_baseline_sources": total_baseline_sources,
        "total_found_sources": total_found_sources,
        "total_overlap_count": total_overlap,
        "overall_overlap_percentage": overlap_percentage,
        "total_high_ranked_baseline_sources": total_high_ranked_baseline,
        "total_high_ranked_found_sources": total_high_ranked_found,
        "total_high_ranked_overlap_count": total_high_ranked_overlap,
        "overall_high_ranked_overlap_percentage": high_ranked_overlap_percentage,
        "avg_baseline_sources_per_question": round(total_baseline_sources / valid_questions,
                                                   2) if valid_questions > 0 else 0,
        "avg_found_sources_per_question": round(total_found_sources / valid_questions,
                                                2) if valid_questions > 0 else 0
    }

    return pd.DataFrame([cumulative_stats])


async def get_unified_sources(conn: asyncpg.Connection, question_id: int, source_finder_run_id: int, ranker_id: int):
    """
    Create unified view of sources from both baseline_sources and source_runs
    with indicators of where each source appears and their respective ranks.
    """

    query_runs = """
                 SELECT tb.tractate_chunk_id as id,
                        sr.rank              as source_rank,
                        sr.tractate,
                        sr.folio,
                        sr.reason            as source_reason
                 FROM source_run_results sr
                          join talmud_bavli tb on sr.sugya_id = tb.xml_id
                 WHERE sr.question_id = $1
                   AND sr.source_finder_run_id = $2
                 """
    source_runs = await conn.fetch(query_runs, question_id, source_finder_run_id)
    # Get sources from baseline_sources
    baseline_query = query_runs.replace("source_rank", "baseline_rank")
    baseline_sources = await conn.fetch(baseline_query, question_id, ranker_id)
    stats_df = await calculate_baseline_vs_source_stats_for_question(conn, baseline_sources, source_runs)
    # Convert to dictionaries for easier lookup
    source_runs_dict = {s["id"]: dict(s) for s in source_runs}
    baseline_dict = {s["id"]: dict(s) for s in baseline_sources}
    # Get all unique sugya_ids
    all_sugya_ids = set(source_runs_dict.keys()) | set(baseline_dict.keys())
    # Build unified results
    unified_results = []
    for sugya_id in all_sugya_ids:
        in_source_run = sugya_id in source_runs_dict
        in_baseline = sugya_id in baseline_dict
        if in_baseline:
            info = baseline_dict[sugya_id]
        else:
            info = source_runs_dict[sugya_id]
        result = {
            "id": sugya_id,
            "tractate": info.get("tractate"),
            "folio": info.get("folio"),
            "in_baseline": "Yes" if in_baseline else "No",
            "baseline_rank": baseline_dict.get(sugya_id, {}).get("baseline_rank", "N/A"),
            "in_source_run": "Yes" if in_source_run else "No",
            "source_run_rank": source_runs_dict.get(sugya_id, {}).get("source_rank", "N/A"),
            "source_reason": source_runs_dict.get(sugya_id, {}).get("reason", "N/A"),
            "metadata": source_runs_dict.get(sugya_id, {}).get("metadata", "")
        }
        unified_results.append(result)

    return unified_results, stats_df


@cached(cache=TTLCache(ttl=1800, maxsize=1024))
async def get_source_text(conn: asyncpg.Connection, tractate_chunk_id: int):
    """
    Retrieves the text content for a given tractate chunk ID.
    """

    query = """
    SELECT tb.text as text
    FROM talmud_bavli tb
    WHERE tb.tractate_chunk_id = $1
    """
    result = await conn.fetchrow(query, tractate_chunk_id)
    return result["text"] if result else "Source text not found"

def get_pg_sync_connection(schema="talmudexplore"):
    conn = psycopg2.connect(dbname=os.getenv("pg_dbname"),
        user=os.getenv("pg_user"),
        password=os.getenv("pg_password"),
        host=os.getenv("pg_host"),
        port=os.getenv("pg_port"),
        options=f"-c search_path={schema}")
    return conn