# -*- coding: utf-8 -*-
"""
待转接队列（本地 SQLite）
用于在设计师不在线时暂存转接请求，待设计师上线后自动转接。
"""

import os
import sqlite3
from datetime import datetime, timedelta
from typing import List, Dict

_DB_PATH = os.path.join(os.path.dirname(__file__), "pending_transfer.db")


def _get_conn() -> sqlite3.Connection:
    conn = sqlite3.connect(_DB_PATH)
    conn.row_factory = sqlite3.Row
    return conn


def init_db():
    os.makedirs(os.path.dirname(_DB_PATH), exist_ok=True)
    with _get_conn() as conn:
        conn.execute(
            """
            CREATE TABLE IF NOT EXISTS pending_transfers (
                id            INTEGER PRIMARY KEY AUTOINCREMENT,
                customer_id   TEXT NOT NULL,
                acc_id        TEXT DEFAULT '',
                acc_type      TEXT DEFAULT '',
                platform      TEXT DEFAULT 'qianniu',
                reason        TEXT DEFAULT '',
                status        TEXT NOT NULL DEFAULT 'pending',
                retry_count   INTEGER NOT NULL DEFAULT 0,
                next_retry_at TEXT NOT NULL,
                created_at    TEXT NOT NULL,
                updated_at    TEXT NOT NULL,
                completed_at  TEXT DEFAULT '',
                last_error    TEXT DEFAULT ''
            )
            """
        )
        conn.execute(
            "CREATE INDEX IF NOT EXISTS idx_pending_status_retry ON pending_transfers(status, next_retry_at)"
        )
        conn.execute(
            "CREATE INDEX IF NOT EXISTS idx_pending_customer_acc ON pending_transfers(customer_id, acc_id)"
        )
        conn.commit()


init_db()


def enqueue_pending_transfer(
    customer_id: str,
    acc_id: str,
    acc_type: str,
    platform: str,
    reason: str,
) -> int:
    now = datetime.now().strftime("%Y-%m-%d %H:%M:%S")
    with _get_conn() as conn:
        row = conn.execute(
            """
            SELECT id
            FROM pending_transfers
            WHERE customer_id = ? AND acc_id = ? AND status IN ('pending', 'processing')
            ORDER BY id DESC
            LIMIT 1
            """,
            (customer_id, acc_id),
        ).fetchone()

        if row:
            conn.execute(
                """
                UPDATE pending_transfers
                SET acc_type = ?, platform = ?, reason = ?, status = 'pending',
                    next_retry_at = ?, updated_at = ?, last_error = ''
                WHERE id = ?
                """,
                (acc_type, platform, reason, now, now, row["id"]),
            )
            conn.commit()
            return int(row["id"])

        cur = conn.execute(
            """
            INSERT INTO pending_transfers
            (customer_id, acc_id, acc_type, platform, reason, status, retry_count, next_retry_at, created_at, updated_at)
            VALUES (?, ?, ?, ?, ?, 'pending', 0, ?, ?, ?)
            """,
            (customer_id, acc_id, acc_type, platform, reason, now, now, now),
        )
        conn.commit()
        return int(cur.lastrowid)


def claim_due_pending_transfers(limit: int = 10) -> List[Dict]:
    now = datetime.now().strftime("%Y-%m-%d %H:%M:%S")
    with _get_conn() as conn:
        conn.execute("BEGIN IMMEDIATE")
        rows = conn.execute(
            """
            SELECT *
            FROM pending_transfers
            WHERE status = 'pending' AND next_retry_at <= ?
            ORDER BY created_at ASC, id ASC
            LIMIT ?
            """,
            (now, limit),
        ).fetchall()

        ids = [int(r["id"]) for r in rows]
        if ids:
            placeholders = ",".join("?" for _ in ids)
            conn.execute(
                f"""
                UPDATE pending_transfers
                SET status = 'processing', updated_at = ?
                WHERE id IN ({placeholders})
                """,
                (now, *ids),
            )
        conn.commit()
        return [dict(r) for r in rows]


def complete_pending_transfer(row_id: int):
    now = datetime.now().strftime("%Y-%m-%d %H:%M:%S")
    with _get_conn() as conn:
        conn.execute(
            """
            UPDATE pending_transfers
            SET status = 'completed', completed_at = ?, updated_at = ?, last_error = ''
            WHERE id = ?
            """,
            (now, now, row_id),
        )
        conn.commit()


def retry_pending_transfer(row_id: int, delay_seconds: int = 60, error: str = ""):
    now = datetime.now()
    next_retry = now + timedelta(seconds=max(delay_seconds, 5))
    now_s = now.strftime("%Y-%m-%d %H:%M:%S")
    next_s = next_retry.strftime("%Y-%m-%d %H:%M:%S")
    with _get_conn() as conn:
        conn.execute(
            """
            UPDATE pending_transfers
            SET status = 'pending',
                retry_count = retry_count + 1,
                next_retry_at = ?,
                updated_at = ?,
                last_error = ?
            WHERE id = ?
            """,
            (next_s, now_s, error[:500], row_id),
        )
        conn.commit()


def count_open_pending_transfers() -> int:
    with _get_conn() as conn:
        row = conn.execute(
            """
            SELECT COUNT(*) AS cnt
            FROM pending_transfers
            WHERE status IN ('pending', 'processing')
            """
        ).fetchone()
    return int(row["cnt"] or 0) if row else 0