"""派发器：按单位/月份汇总任务 → 生成派发 payload JSON → 写派发日志。

v1.1.0 dry-run 模式：payload 写 data/dispatch/{unit}_{month}.json，
但**不真正调用企业微信 API**。开发者后续接入：
- 真实 API：调用 WECOM_API_BASE_URL + WECOM_API_TOKEN
- 在 dispatch_log 写 status='sent' 而非 'dry_run'
"""

from __future__ import annotations

import json
import sqlite3
import uuid
from datetime import datetime
from pathlib import Path

from db import repository as repo
from util.date_util import parse_iso_date
from util.logging_setup import get_skill_logger
from util.runtime_paths import get_dispatch_dir

logger = get_skill_logger()


def build_payload(
    conn: sqlite3.Connection,
    unit_id: str,
    month: str = "",
) -> dict:
    """构建派发 payload：含单位、月份、任务清单、收件人、消息正文。"""
    rows = repo.list_open_alerts_by_unit_month(conn, unit_id, month)

    # 单位名（取第一条）
    unit_name = rows[0]["unit_name"] if rows else "(无)"

    items = []
    for r in rows:
        items.append({
            "contract_id": r["contract_id"],
            "teacher_name": r["teacher_name"],
            "alert_level": r["alert_level"],
            "days_to_expire": r["days_to_expire"],
            "contract_end": r["contract_end"],
        })

    if month:
        title = f"{unit_name} {month} 合同到期人员清单及续聘建议"
    else:
        title = f"{unit_name} 待续聘合同清单"

    body_lines = [
        title,
        "",
        f"共 {len(items)} 份合同需在到期前办理续聘手续。",
        "",
    ]
    for it in items:
        level_zh = {"yellow": "黄色", "orange": "橙色", "red": "红色"}.get(
            it["alert_level"], it["alert_level"]
        )
        body_lines.append(
            f"- {it['teacher_name']}（合同至 {it['contract_end']}，{level_zh}预警，距到期 {it['days_to_expire']} 天）"
        )
    body_lines.append("")
    body_lines.append("请人事秘书尽快通知相关教师备齐续聘材料。")

    payload = {
        "schema_version": 1,
        "channel": "wecom",
        "dry_run": True,
        "to": {
            "unit_id": unit_id,
            "unit_name": unit_name,
            "role": "人事秘书",
        },
        "title": title,
        "body": "\n".join(body_lines),
        "items": items,
        "generated_at": datetime.now().isoformat(timespec="seconds"),
    }
    return payload


def dispatch(
    conn: sqlite3.Connection,
    unit_id: str,
    month: str = "",
) -> dict:
    """派发 dry-run：写 payload 文件 + 写 dispatch_log。"""
    payload = build_payload(conn, unit_id, month)
    items = payload["items"]
    task_ids = [f"T-{it['contract_id']}" for it in items]

    dispatch_dir = get_dispatch_dir()
    dispatch_dir.mkdir(parents=True, exist_ok=True)

    month_part = month or "all"
    payload_path = dispatch_dir / f"{unit_id}_{month_part}.json"
    payload_path.write_text(
        json.dumps(payload, ensure_ascii=False, indent=2),
        encoding="utf-8",
    )

    log_id = f"L-{uuid.uuid4().hex[:8]}"
    repo.insert_dispatch_log(
        conn, log_id, unit_id, month or "all", task_ids, str(payload_path),
        status="dry_run",
    )
    conn.commit()

    logger.info(
        "dispatcher: unit=%s month=%s items=%d payload=%s log=%s",
        unit_id, month or "(all)", len(items), payload_path, log_id,
    )
    return {
        "log_id": log_id,
        "unit_id": unit_id,
        "unit_name": payload["to"]["unit_name"],
        "month": month or "(all)",
        "item_count": len(items),
        "payload_path": str(payload_path),
        "status": "dry_run",
    }