"""
CLI command for refreshing pathway data from Snowflake.

This command fetches activity data from Snowflake, processes it through the
pathway pipeline for all 6 date filter combinations, and stores the results
in the SQLite pathway_nodes table. Supports two chart types:
- "directory": Trust → Directory → Drug → Pathway (default)
- "indication": Trust → Search_Term → Drug → Pathway (requires GP diagnosis lookup)

Usage:
    python -m cli.refresh_pathways
    python -m cli.refresh_pathways --minimum-patients 10
    python -m cli.refresh_pathways --provider-codes RGT,RM1
    python -m cli.refresh_pathways --chart-type all
    python -m cli.refresh_pathways --chart-type directory
    python -m cli.refresh_pathways --dry-run

Run `python -m cli.refresh_pathways --help` for full options.
"""

import argparse
import json
import sqlite3
import sys
import time
import uuid
from datetime import datetime
from pathlib import Path
from typing import Optional

from core import PathConfig, default_paths
from core.logging_config import get_logger, setup_logging
from data_processing.database import DatabaseManager, DatabaseConfig
from data_processing.schema import (
    clear_pathway_nodes,
    get_pathway_table_counts,
    verify_pathway_tables_exist,
    create_pathway_tables,
)
from data_processing.pathway_pipeline import (
    ChartType,
    DATE_FILTER_CONFIGS,
    fetch_and_transform_data,
    process_all_date_filters,
    process_pathway_for_date_filter,
    process_indication_pathway_for_date_filter,
    extract_denormalized_fields,
    extract_indication_fields,
    convert_to_records,
)
from data_processing.diagnosis_lookup import (
    assign_drug_indications,
    get_patient_indication_groups,
    load_drug_indication_mapping,
)

logger = get_logger(__name__)


def get_default_filters(paths: PathConfig) -> tuple[list[str], list[str], list[str]]:
    """
    Load default filter values from reference files.

    Returns:
        Tuple of (trust_filter, drug_filter, directory_filter)
    """
    import pandas as pd

    # Load default trusts
    trust_filter = []
    if paths.default_trusts_csv.exists():
        try:
            trusts_df = pd.read_csv(paths.default_trusts_csv)
            # Use the "Name" column which contains trust names
            if 'Name' in trusts_df.columns:
                trust_filter = trusts_df['Name'].dropna().tolist()
            else:
                # Fallback to first column if no Name column
                trust_filter = trusts_df.iloc[:, 0].dropna().tolist()
            logger.info(f"Loaded {len(trust_filter)} default trusts")
        except Exception as e:
            logger.warning(f"Could not load default trusts: {e}")

    # Load default drugs (Include=1 in include.csv)
    drug_filter = []
    if paths.include_csv.exists():
        try:
            drugs_df = pd.read_csv(paths.include_csv)
            if 'Include' in drugs_df.columns:
                drug_filter = drugs_df[drugs_df['Include'] == 1].iloc[:, 0].dropna().tolist()
            else:
                # Assume first column contains drug names if no Include column
                drug_filter = drugs_df.iloc[:, 0].dropna().tolist()
            logger.info(f"Loaded {len(drug_filter)} default drugs")
        except Exception as e:
            logger.warning(f"Could not load default drugs: {e}")

    # Load default directories
    directory_filter = []
    if paths.directory_list_csv.exists():
        try:
            dirs_df = pd.read_csv(paths.directory_list_csv)
            # Assume first column contains directory names
            directory_filter = dirs_df.iloc[:, 0].dropna().tolist()
            logger.info(f"Loaded {len(directory_filter)} default directories")
        except Exception as e:
            logger.warning(f"Could not load default directories: {e}")

    return trust_filter, drug_filter, directory_filter


def insert_pathway_records(
    conn: sqlite3.Connection,
    records: list[dict],
) -> int:
    """
    Insert pathway records into pathway_nodes table.

    Uses INSERT OR REPLACE to handle updates to existing records.

    Args:
        conn: SQLite connection
        records: List of record dicts from convert_to_records()

    Returns:
        Number of records inserted
    """
    if not records:
        return 0

    # Column order matching pathway_nodes schema (includes chart_type)
    columns = [
        'date_filter_id', 'chart_type', 'parents', 'ids', 'labels', 'level',
        'value', 'cost', 'costpp', 'cost_pp_pa', 'colour',
        'first_seen', 'last_seen', 'first_seen_parent', 'last_seen_parent',
        'average_spacing', 'average_administered', 'avg_days',
        'trust_name', 'directory', 'drug_sequence', 'data_refresh_id'
    ]

    placeholders = ', '.join(['?' for _ in columns])
    column_names = ', '.join(columns)

    insert_sql = f"""
        INSERT OR REPLACE INTO pathway_nodes ({column_names})
        VALUES ({placeholders})
    """

    # Convert records to tuples in column order
    rows = []
    for record in records:
        row = tuple(record.get(col) for col in columns)
        rows.append(row)

    cursor = conn.executemany(insert_sql, rows)
    return cursor.rowcount


def log_refresh_start(
    conn: sqlite3.Connection,
    refresh_id: str,
    date_from: Optional[str] = None,
    date_to: Optional[str] = None,
) -> None:
    """Log the start of a refresh operation."""
    conn.execute("""
        INSERT INTO pathway_refresh_log
        (refresh_id, started_at, status, snowflake_query_date_from, snowflake_query_date_to)
        VALUES (?, ?, 'running', ?, ?)
    """, (refresh_id, datetime.now().isoformat(), date_from, date_to))
    conn.commit()


def log_refresh_complete(
    conn: sqlite3.Connection,
    refresh_id: str,
    record_count: int,
    date_filter_counts: dict[str, int],
    duration_seconds: float,
    source_row_count: Optional[int] = None,
) -> None:
    """Log the successful completion of a refresh operation."""
    conn.execute("""
        UPDATE pathway_refresh_log
        SET completed_at = ?,
            status = 'completed',
            record_count = ?,
            date_filter_counts = ?,
            processing_duration_seconds = ?,
            source_row_count = ?
        WHERE refresh_id = ?
    """, (
        datetime.now().isoformat(),
        record_count,
        json.dumps(date_filter_counts),
        duration_seconds,
        source_row_count,
        refresh_id,
    ))
    conn.commit()


def log_refresh_failed(
    conn: sqlite3.Connection,
    refresh_id: str,
    error_message: str,
    duration_seconds: float,
) -> None:
    """Log a failed refresh operation."""
    conn.execute("""
        UPDATE pathway_refresh_log
        SET completed_at = ?,
            status = 'failed',
            error_message = ?,
            processing_duration_seconds = ?
        WHERE refresh_id = ?
    """, (
        datetime.now().isoformat(),
        error_message,
        duration_seconds,
        refresh_id,
    ))
    conn.commit()


def refresh_pathways(
    minimum_patients: int = 5,
    provider_codes: Optional[list[str]] = None,
    trust_filter: Optional[list[str]] = None,
    drug_filter: Optional[list[str]] = None,
    directory_filter: Optional[list[str]] = None,
    db_path: Optional[Path] = None,
    paths: Optional[PathConfig] = None,
    dry_run: bool = False,
    chart_type: str = "directory",
) -> tuple[bool, str, dict]:
    """
    Main refresh function that orchestrates the full pipeline.

    Args:
        minimum_patients: Minimum patients to include a pathway
        provider_codes: List of provider codes to filter Snowflake query
        trust_filter: List of trust names to include in pathways
        drug_filter: List of drug names to include in pathways
        directory_filter: List of directories to include in pathways
        db_path: Path to SQLite database (uses default if None)
        paths: PathConfig for file paths
        dry_run: If True, don't actually insert records
        chart_type: Which chart type to process: "directory", "indication", or "all"

    Returns:
        Tuple of (success: bool, message: str, stats: dict)
    """
    if paths is None:
        paths = default_paths

    # Set up database connection
    if db_path:
        db_config = DatabaseConfig(db_path=db_path)
    else:
        db_config = DatabaseConfig(data_dir=paths.data_dir)

    db_manager = DatabaseManager(db_config)

    # Load default filters if not provided
    default_trusts, default_drugs, default_dirs = get_default_filters(paths)

    if trust_filter is None:
        trust_filter = default_trusts
    if drug_filter is None:
        drug_filter = default_drugs
    if directory_filter is None:
        directory_filter = default_dirs

    # Ensure we have some filters
    if not drug_filter:
        return False, "No drugs specified and could not load defaults", {}

    # Determine which chart types to process
    if chart_type == "all":
        chart_types_to_process: list[ChartType] = ["directory", "indication"]
    else:
        chart_types_to_process = [chart_type]  # type: ignore

    logger.info("=" * 60)
    logger.info("Pathway Data Refresh Starting")
    logger.info("=" * 60)
    logger.info(f"Minimum patients: {minimum_patients}")
    logger.info(f"Trust filter: {len(trust_filter)} trusts")
    logger.info(f"Drug filter: {len(drug_filter)} drugs")
    logger.info(f"Directory filter: {len(directory_filter)} directories")
    logger.info(f"Provider codes: {provider_codes or 'All'}")
    logger.info(f"Chart type(s): {', '.join(chart_types_to_process)}")
    logger.info(f"Database: {db_manager.db_path}")
    logger.info(f"Dry run: {dry_run}")
    logger.info("=" * 60)

    start_time = time.time()
    refresh_id = str(uuid.uuid4())[:8]
    stats = {
        "refresh_id": refresh_id,
        "date_filter_counts": {},
        "total_records": 0,
        "snowflake_rows": 0,
    }

    try:
        # Verify database and tables
        with db_manager.get_connection() as conn:
            missing_tables = verify_pathway_tables_exist(conn)
            if missing_tables:
                logger.info(f"Creating missing tables: {missing_tables}")
                create_pathway_tables(conn)

            # Log refresh start
            if not dry_run:
                log_refresh_start(conn, refresh_id)

        # Step 1: Fetch data from Snowflake
        logger.info("")
        logger.info("Step 1/4: Fetching data from Snowflake...")
        df = fetch_and_transform_data(
            provider_codes=provider_codes,
            paths=paths,
        )

        if df.empty:
            msg = "No data returned from Snowflake"
            logger.error(msg)
            with db_manager.get_connection() as conn:
                log_refresh_failed(conn, refresh_id, msg, time.time() - start_time)
            return False, msg, stats

        stats["snowflake_rows"] = len(df)
        logger.info(f"Fetched {len(df)} records from Snowflake")

        # Step 2: Process all date filters for each chart type
        num_date_filters = len(DATE_FILTER_CONFIGS)
        num_chart_types = len(chart_types_to_process)
        total_datasets = num_date_filters * num_chart_types

        logger.info("")
        logger.info(f"Step 2/4: Processing pathway data for {total_datasets} datasets "
                   f"({num_date_filters} date filters x {num_chart_types} chart types)...")

        # Store results keyed by "date_filter_id:chart_type"
        results: dict[str, list[dict]] = {}

        for current_chart_type in chart_types_to_process:
            logger.info("")
            logger.info(f"Processing chart type: {current_chart_type}")

            if current_chart_type == "directory":
                # Use existing process_all_date_filters for directory charts
                dir_results = process_all_date_filters(
                    df=df,
                    trust_filter=trust_filter,
                    drug_filter=drug_filter,
                    directory_filter=directory_filter,
                    minimum_patients=minimum_patients,
                    refresh_id=refresh_id,
                    paths=paths,
                )
                # Add results with chart_type suffix
                for filter_id, records in dir_results.items():
                    # Records already have chart_type set by convert_to_records
                    results[f"{filter_id}:directory"] = records

            elif current_chart_type == "indication":
                # For indication charts, use drug-aware matching:
                # 1. Get ALL GP diagnosis matches per patient (with code_frequency)
                # 2. Cross-reference with drug-to-Search_Term mapping from DimSearchTerm.csv
                # 3. Assign each drug to its matched indication via modified UPIDs
                logger.info("Building drug-aware indication groups...")

                # Check Snowflake availability
                from data_processing.snowflake_connector import get_connector, is_snowflake_available

                if not is_snowflake_available():
                    logger.warning("Snowflake not available - cannot process indication charts")
                    for config in DATE_FILTER_CONFIGS:
                        results[f"{config.id}:indication"] = []
                    continue

                try:
                    import pandas as pd
                    connector = get_connector()

                    if 'PseudoNHSNoLinked' not in df.columns:
                        logger.error("DataFrame missing 'PseudoNHSNoLinked' column - cannot lookup GP records")
                        for config in DATE_FILTER_CONFIGS:
                            results[f"{config.id}:indication"] = []
                        continue

                    # Step 1: Load drug-to-Search_Term mapping from DimSearchTerm.csv
                    _, search_term_to_fragments = load_drug_indication_mapping()
                    logger.info(f"Loaded drug mapping: {len(search_term_to_fragments)} Search_Terms")

                    # Step 2: Get ALL GP diagnosis matches per patient (with code_frequency)
                    patient_pseudonyms = df['PseudoNHSNoLinked'].dropna().unique().tolist()
                    logger.info(f"Looking up GP diagnoses for {len(patient_pseudonyms)} unique patients...")

                    # Restrict GP codes to HCD data window (reduces noise from old diagnoses)
                    earliest_hcd_date = df['Intervention Date'].min()
                    if pd.notna(earliest_hcd_date):
                        earliest_hcd_date_str = pd.Timestamp(earliest_hcd_date).strftime('%Y-%m-%d')
                        logger.info(f"Restricting GP codes to HCD window: >= {earliest_hcd_date_str}")
                    else:
                        earliest_hcd_date_str = None

                    gp_matches_df = get_patient_indication_groups(
                        patient_pseudonyms=patient_pseudonyms,
                        connector=connector,
                        batch_size=5000,
                        earliest_hcd_date=earliest_hcd_date_str,
                    )

                    # Step 3: Assign drug-aware indications using cross-referencing
                    # This replaces the old per-patient approach with per-drug matching
                    modified_df, indication_df = assign_drug_indications(
                        df=df,
                        gp_matches_df=gp_matches_df,
                        search_term_to_fragments=search_term_to_fragments,
                    )

                    logger.info(f"Drug-aware indication matching complete. "
                               f"Modified UPIDs: {modified_df['UPID'].nunique()}, "
                               f"Indication groups: {len(indication_df)}")

                    if indication_df.empty:
                        logger.warning("Empty indication_df - skipping indication charts")
                        for config in DATE_FILTER_CONFIGS:
                            results[f"{config.id}:indication"] = []
                    else:
                        # Process each date filter with drug-aware indication grouping
                        # Use modified_df (with indication-aware UPIDs) instead of original df
                        for config in DATE_FILTER_CONFIGS:
                            logger.info(f"Processing indication pathway for {config.id}")

                            ice_df = process_indication_pathway_for_date_filter(
                                df=modified_df,
                                indication_df=indication_df,
                                config=config,
                                trust_filter=trust_filter,
                                drug_filter=drug_filter,
                                directory_filter=directory_filter,
                                minimum_patients=minimum_patients,
                                paths=paths,
                            )

                            if ice_df is None:
                                logger.warning(f"No indication pathway data for {config.id}")
                                results[f"{config.id}:indication"] = []
                                continue

                            # Extract denormalized fields (using indication variant)
                            ice_df = extract_indication_fields(ice_df)

                            # Convert to records with chart_type="indication"
                            records = convert_to_records(ice_df, config.id, refresh_id, chart_type="indication")
                            results[f"{config.id}:indication"] = records

                            logger.info(f"Completed {config.id}:indication: {len(records)} nodes")

                except Exception as e:
                    logger.error(f"Error processing indication charts: {e}")
                    logger.exception(e)
                    for config in DATE_FILTER_CONFIGS:
                        results[f"{config.id}:indication"] = []

        # Count records per filter and chart type
        stats["chart_type_counts"] = {}
        for key, records in results.items():
            stats["date_filter_counts"][key] = len(records)
            stats["total_records"] += len(records)
            # Also track by chart type
            _, ct = key.split(":")
            stats["chart_type_counts"][ct] = stats["chart_type_counts"].get(ct, 0) + len(records)

        logger.info("")
        logger.info(f"Processed {stats['total_records']} total pathway nodes")
        for chart_type_name, count in stats.get("chart_type_counts", {}).items():
            logger.info(f"  {chart_type_name}: {count} nodes total")
        for key, count in sorted(stats["date_filter_counts"].items()):
            if count > 0:
                logger.info(f"    {key}: {count} nodes")

        if dry_run:
            logger.info("")
            logger.info("DRY RUN - Skipping database insertion")
            elapsed = time.time() - start_time
            return True, f"Dry run complete: {stats['total_records']} records would be inserted", stats

        # Step 3: Clear existing data and insert new records
        logger.info("")
        logger.info("Step 3/4: Clearing existing pathway data and inserting new records...")

        with db_manager.get_transaction() as conn:
            # Clear all existing pathway nodes
            deleted = clear_pathway_nodes(conn)
            logger.info(f"Cleared {deleted} existing pathway nodes")

            # Insert new records for each date filter + chart type combination
            total_inserted = 0
            for key, records in results.items():
                if records:
                    inserted = insert_pathway_records(conn, records)
                    total_inserted += len(records)
                    logger.info(f"  Inserted {len(records)} records for {key}")

        # Step 4: Log completion
        logger.info("")
        logger.info("Step 4/4: Logging refresh completion...")

        elapsed = time.time() - start_time

        with db_manager.get_connection() as conn:
            log_refresh_complete(
                conn=conn,
                refresh_id=refresh_id,
                record_count=stats["total_records"],
                date_filter_counts=stats["date_filter_counts"],
                duration_seconds=elapsed,
                source_row_count=stats.get("snowflake_rows"),
            )

            # Verify final counts
            counts = get_pathway_table_counts(conn)
            logger.info(f"Final table counts: {counts}")

        logger.info("")
        logger.info("=" * 60)
        logger.info(f"Refresh completed successfully in {elapsed:.1f} seconds")
        logger.info(f"Total records: {stats['total_records']}")
        logger.info(f"Refresh ID: {refresh_id}")
        logger.info("=" * 60)

        return True, f"Refresh complete: {stats['total_records']} records in {elapsed:.1f}s", stats

    except Exception as e:
        elapsed = time.time() - start_time
        error_msg = f"Refresh failed: {e}"
        logger.error(error_msg, exc_info=True)

        try:
            with db_manager.get_connection() as conn:
                log_refresh_failed(conn, refresh_id, str(e), elapsed)
        except Exception:
            pass  # Don't fail the error handling

        return False, error_msg, stats


def main() -> int:
    """CLI entry point."""
    parser = argparse.ArgumentParser(
        description="Refresh pathway data from Snowflake",
        formatter_class=argparse.RawDescriptionHelpFormatter,
        epilog="""
Examples:
    # Basic refresh with defaults (directory chart only)
    python -m cli.refresh_pathways

    # Refresh both chart types (directory and indication)
    python -m cli.refresh_pathways --chart-type all

    # Refresh only indication-based charts
    python -m cli.refresh_pathways --chart-type indication

    # Refresh with custom minimum patients
    python -m cli.refresh_pathways --minimum-patients 10

    # Refresh specific providers only
    python -m cli.refresh_pathways --provider-codes RGT,RM1

    # Dry run to see what would be processed
    python -m cli.refresh_pathways --dry-run

    # Verbose output
    python -m cli.refresh_pathways --verbose
        """
    )

    parser.add_argument(
        "--minimum-patients",
        type=int,
        default=5,
        help="Minimum patients to include a pathway (default: 5)"
    )

    parser.add_argument(
        "--provider-codes",
        type=str,
        default=None,
        help="Comma-separated list of provider codes to filter (default: all)"
    )

    parser.add_argument(
        "--db-path",
        type=str,
        default=None,
        help="Path to SQLite database (default: data/pathways.db)"
    )

    parser.add_argument(
        "--dry-run",
        action="store_true",
        help="Process data but don't insert into database"
    )

    parser.add_argument(
        "--chart-type",
        type=str,
        choices=["directory", "indication", "all"],
        default="directory",
        help="Chart type to process: 'directory' (default), 'indication', or 'all'"
    )

    parser.add_argument(
        "--verbose", "-v",
        action="store_true",
        help="Enable verbose logging"
    )

    args = parser.parse_args()

    # Configure logging
    import logging
    log_level = logging.DEBUG if args.verbose else logging.INFO
    setup_logging(level=log_level)

    # Parse provider codes
    provider_codes = None
    if args.provider_codes:
        provider_codes = [code.strip() for code in args.provider_codes.split(",")]

    # Parse db path
    db_path = Path(args.db_path) if args.db_path else None

    # Run the refresh
    success, message, stats = refresh_pathways(
        minimum_patients=args.minimum_patients,
        provider_codes=provider_codes,
        db_path=db_path,
        dry_run=args.dry_run,
        chart_type=args.chart_type,
    )

    if success:
        print(f"\n[OK] {message}")
        return 0
    else:
        print(f"\n[FAILED] {message}", file=sys.stderr)
        return 1


if __name__ == "__main__":
    sys.exit(main())