from __future__ import annotations

from pathlib import Path
from typing import Dict, Iterable, Optional

import psycopg2
import psycopg2.extras
from dotenv import load_dotenv

from uv_app.core.mssql import connect_to_mssql
from uv_app.core.pgsql import connect_to_pgsql

MIN_YEAR = 2000
OPEN_END_DATE = "3999-01-01"
SERVICE_CODE = "STATUSAS"

DOTENV_PATH = Path(__file__).resolve().parents[2] / ".env"
load_dotenv(DOTENV_PATH, override=True)

QUERY_PATH = Path(__file__).with_name("bukle_by_sutarties_kodas.sql")


def _read_query() -> str:
    return QUERY_PATH.read_text(encoding="utf-8")


def _fetch_pg_rows(sutarties_kodas: str) -> Iterable[Dict[str, object]]:
    conn = connect_to_pgsql()
    if conn is None:
        raise RuntimeError("Failed to connect to PostgreSQL.")
    try:
        with conn.cursor(cursor_factory=psycopg2.extras.RealDictCursor) as cursor:
            cursor.execute(_read_query(), (sutarties_kodas,))
            return cursor.fetchall()
    finally:
        conn.close()


def _fetch_mssql_appendices(contract_code: str) -> list[dict[str, object]]:
    conn = connect_to_mssql()
    if conn is None:
        raise RuntimeError("Failed to connect to MSSQL.")
    try:
        cursor = conn.cursor()
        cursor.execute(
            """
            SELECT
                N52_KODAS_KT,
                N52_KODAS_K0,
                N52_DOK_NR,
                N52_KODAS,
                CONVERT(date, N52_BEG_DATE) AS N52_BEG_DATE,
                CONVERT(date, N52_END_DATE) AS N52_END_DATE,
                N52_VISKAS
            FROM dbo.N52_SUTD
            WHERE N52_KODAS_KT = ?
              AND N52_KODAS = ?
            """,
            (contract_code, SERVICE_CODE),
        )
        rows = cursor.fetchall()
        columns = [c[0] for c in cursor.description]
        return [dict(zip(columns, row)) for row in rows]
    finally:
        conn.close()


def _normalize_date(value: object) -> str:
    if value is None:
        return ""
    return str(value)


def _build_periods(rows: list[dict[str, object]]) -> list[dict[str, object]]:
    normalized = []
    for row in rows:
        start = row.get("data")
        if start is None or str(start) < f"{MIN_YEAR}-01-01":
            start = f"{MIN_YEAR}-01-01"
        normalized.append(
            {
                "start": start,
                "bukle": int(row["bukle"]),
            }
        )
    normalized.sort(key=lambda item: str(item["start"]))
    periods = []
    for idx, item in enumerate(normalized):
        start_date = str(item["start"])
        if idx == len(normalized) - 1:
            end_date = OPEN_END_DATE
        else:
            next_start = normalized[idx + 1]["start"]
            end_date = str(next_start - date.resolution)
        active = item["bukle"] in {2, 3}
        periods.append(
            {
                "start": start_date,
                "end": end_date,
                "active": active,
                "k0": f"{SERVICE_CODE}-{idx + 1}",
                "dok_nr": str(idx + 1),
            }
        )
    return periods


def _explain_mismatch(existing: list[dict[str, object]], desired: list[dict[str, object]]) -> None:
    print("=== Desired (from PGSQL) ===")
    for row in desired:
        print(row)
    print("=== Existing (from MSSQL) ===")
    for row in existing:
        print(
            {
                "k0": str(row.get("N52_KODAS_K0") or "").strip(),
                "dok_nr": str(row.get("N52_DOK_NR") or "").strip(),
                "start": _normalize_date(row.get("N52_BEG_DATE")),
                "end": _normalize_date(row.get("N52_END_DATE")),
                "active": int(row.get("N52_VISKAS") or 0) == 1,
            }
        )

    existing_keys = {
        (
            _normalize_date(row.get("N52_BEG_DATE")),
            _normalize_date(row.get("N52_END_DATE")),
            int(row.get("N52_VISKAS") or 0) == 1,
            str(row.get("N52_KODAS_K0") or "").strip(),
            str(row.get("N52_DOK_NR") or "").strip(),
        )
        for row in existing
    }
    desired_keys = {
        (
            row["start"],
            row["end"],
            row["active"],
            row["k0"],
            row["dok_nr"],
        )
        for row in desired
    }

    print("=== Missing in MSSQL ===")
    for key in sorted(desired_keys - existing_keys):
        print(key)

    print("=== Extra in MSSQL ===")
    for key in sorted(existing_keys - desired_keys):
        print(key)


def main() -> None:
    sutarties_kodas = input("Sutarties kodas: ").strip()
    if not sutarties_kodas:
        print("Missing sutarties kodas.")
        return
    rows = list(_fetch_pg_rows(sutarties_kodas))
    if not rows:
        print("No bukle rows found in PGSQL.")
        return
    contract_code = f"SUT-{sutarties_kodas}"
    existing = _fetch_mssql_appendices(contract_code)
    desired = _build_periods(rows)
    _explain_mismatch(existing, desired)


if __name__ == "__main__":
    main()