"""
任务管理服务

负责任务 CRUD、置顶、放弃、取消放弃等操作。
通过 FDW 读取客户信息和 RS 指数，计算爱心 icon 档位。
"""

import json
import logging
from decimal import Decimal

from fastapi import HTTPException

from app.services.task_generator import compute_heart_icon

logger = logging.getLogger(__name__)


def _get_connection():
    """延迟导入 get_connection，避免纯函数测试时触发模块级导入失败。"""
    from app.database import get_connection

    return get_connection()


def _record_history(
    cur,
    task_id: int,
    action: str,
    old_status: str | None = None,
    new_status: str | None = None,
    old_task_type: str | None = None,
    new_task_type: str | None = None,
    detail: dict | None = None,
) -> None:
    """在 coach_task_history 中记录变更。"""
    cur.execute(
        """
        INSERT INTO biz.coach_task_history
            (task_id, action, old_status, new_status,
             old_task_type, new_task_type, detail)
        VALUES (%s, %s, %s, %s, %s, %s, %s)
        """,
        (
            task_id,
            action,
            old_status,
            new_status,
            old_task_type,
            new_task_type,
            json.dumps(detail) if detail else None,
        ),
    )


def _get_assistant_id(conn, user_id: int, site_id: int) -> int:
    """
    通过 user_assistant_binding 获取 assistant_id。

    找不到绑定关系时抛出 403。
    """
    with conn.cursor() as cur:
        cur.execute(
            """
            SELECT assistant_id
            FROM auth.user_assistant_binding
            WHERE user_id = %s AND site_id = %s AND assistant_id IS NOT NULL
            LIMIT 1
            """,
            (user_id, site_id),
        )
        row = cur.fetchone()
    if not row:
        raise HTTPException(status_code=403, detail="权限不足")
    return row[0]


def _verify_task_ownership(
    conn, task_id: int, assistant_id: int, site_id: int, required_status: str | None = None
) -> dict:
    """
    验证任务归属并返回任务信息。

    - 任务不存在 → 404
    - 不属于当前助教 → 403
    - required_status 不匹配 → 409
    """
    with conn.cursor() as cur:
        cur.execute(
            """
            SELECT id, task_type, status, is_pinned, abandon_reason,
                   assistant_id, site_id
            FROM biz.coach_tasks
            WHERE id = %s
            """,
            (task_id,),
        )
        row = cur.fetchone()

    if not row:
        raise HTTPException(status_code=404, detail="资源不存在")

    task = {
        "id": row[0],
        "task_type": row[1],
        "status": row[2],
        "is_pinned": row[3],
        "abandon_reason": row[4],
        "assistant_id": row[5],
        "site_id": row[6],
    }

    if task["site_id"] != site_id or task["assistant_id"] != assistant_id:
        raise HTTPException(status_code=403, detail="权限不足")

    if required_status and task["status"] != required_status:
        raise HTTPException(status_code=409, detail="任务状态不允许此操作")

    return task


async def get_task_list(user_id: int, site_id: int) -> list[dict]:
    """
    获取助教的活跃任务列表。

    1. 通过 auth.user_assistant_binding 获取 assistant_id
    2. 查询 biz.coach_tasks WHERE status='active'
    3. 通过 FDW 读取客户基本信息（dim_member）和 RS 指数
    4. 计算爱心 icon 档位
    5. 排序：is_pinned DESC, priority_score DESC, created_at ASC

    FDW 查询需要 SET LOCAL app.current_site_id。
    """
    conn = _get_connection()
    try:
        assistant_id = _get_assistant_id(conn, user_id, site_id)

        # 查询活跃任务
        with conn.cursor() as cur:
            cur.execute(
                """
                SELECT id, task_type, status, priority_score, is_pinned,
                       expires_at, created_at, member_id
                FROM biz.coach_tasks
                WHERE site_id = %s
                  AND assistant_id = %s
                  AND status = 'active'
                ORDER BY is_pinned DESC, priority_score DESC NULLS LAST, created_at ASC
                """,
                (site_id, assistant_id),
            )
            tasks = cur.fetchall()
        conn.commit()

        if not tasks:
            return []

        member_ids = list({t[7] for t in tasks})

        # 通过 FDW 读取客户信息和 RS 指数（需要 SET LOCAL app.current_site_id）
        member_info_map: dict[int, dict] = {}
        rs_map: dict[int, Decimal] = {}

        with conn.cursor() as cur:
            cur.execute("BEGIN")
            cur.execute(
                "SET LOCAL app.current_site_id = %s", (str(site_id),)
            )

            # 读取客户基本信息
            cur.execute(
                """
                SELECT member_id, member_name, member_phone
                FROM fdw_etl.v_dim_member
                WHERE member_id = ANY(%s)
                """,
                (member_ids,),
            )
            for row in cur.fetchall():
                member_info_map[row[0]] = {
                    "member_name": row[1],
                    "member_phone": row[2],
                }

            # 读取 RS 指数
            cur.execute(
                """
                SELECT member_id, COALESCE(rs_display, 0)
                FROM fdw_etl.v_dws_member_assistant_relation_index
                WHERE assistant_id = %s
                  AND member_id = ANY(%s)
                """,
                (assistant_id, member_ids),
            )
            for row in cur.fetchall():
                rs_map[row[0]] = Decimal(str(row[1]))

        conn.commit()

        # 组装结果
        result = []
        for task_row in tasks:
            (task_id, task_type, status, priority_score,
             is_pinned, expires_at, created_at, member_id) = task_row

            info = member_info_map.get(member_id, {})
            rs_score = rs_map.get(member_id, Decimal("0"))
            heart_icon = compute_heart_icon(rs_score)

            result.append({
                "id": task_id,
                "task_type": task_type,
                "status": status,
                "priority_score": float(priority_score) if priority_score else None,
                "is_pinned": is_pinned,
                "expires_at": expires_at.isoformat() if expires_at else None,
                "created_at": created_at.isoformat() if created_at else None,
                "member_id": member_id,
                "member_name": info.get("member_name"),
                "member_phone": info.get("member_phone"),
                "rs_score": float(rs_score),
                "heart_icon": heart_icon,
            })

        return result

    finally:
        conn.close()


async def pin_task(task_id: int, user_id: int, site_id: int) -> dict:
    """
    置顶任务。

    验证任务归属后设置 is_pinned=TRUE，记录 history。
    """
    conn = _get_connection()
    try:
        assistant_id = _get_assistant_id(conn, user_id, site_id)
        task = _verify_task_ownership(
            conn, task_id, assistant_id, site_id, required_status="active"
        )

        with conn.cursor() as cur:
            cur.execute("BEGIN")
            cur.execute(
                """
                UPDATE biz.coach_tasks
                SET is_pinned = TRUE, updated_at = NOW()
                WHERE id = %s
                """,
                (task_id,),
            )
            _record_history(
                cur,
                task_id,
                action="pin",
                old_status="active",
                new_status="active",
                old_task_type=task["task_type"],
                new_task_type=task["task_type"],
                detail={"is_pinned": True},
            )
        conn.commit()

        return {"id": task_id, "is_pinned": True}

    finally:
        conn.close()


async def unpin_task(task_id: int, user_id: int, site_id: int) -> dict:
    """
    取消置顶。

    验证任务归属后设置 is_pinned=FALSE。
    """
    conn = _get_connection()
    try:
        assistant_id = _get_assistant_id(conn, user_id, site_id)
        task = _verify_task_ownership(
            conn, task_id, assistant_id, site_id, required_status="active"
        )

        with conn.cursor() as cur:
            cur.execute("BEGIN")
            cur.execute(
                """
                UPDATE biz.coach_tasks
                SET is_pinned = FALSE, updated_at = NOW()
                WHERE id = %s
                """,
                (task_id,),
            )
        conn.commit()

        return {"id": task_id, "is_pinned": False}

    finally:
        conn.close()


async def abandon_task(
    task_id: int, user_id: int, site_id: int, reason: str
) -> dict:
    """
    放弃任务。

    1. 验证 reason 非空（空或纯空白 → 422）
    2. 验证任务归属和 status='active'
    3. 设置 status='abandoned', abandon_reason=reason
    4. 记录 coach_task_history
    """
    if not reason or not reason.strip():
        raise HTTPException(status_code=422, detail="放弃原因不能为空")

    conn = _get_connection()
    try:
        assistant_id = _get_assistant_id(conn, user_id, site_id)
        task = _verify_task_ownership(
            conn, task_id, assistant_id, site_id, required_status="active"
        )

        with conn.cursor() as cur:
            cur.execute("BEGIN")
            cur.execute(
                """
                UPDATE biz.coach_tasks
                SET status = 'abandoned',
                    abandon_reason = %s,
                    updated_at = NOW()
                WHERE id = %s
                """,
                (reason, task_id),
            )
            _record_history(
                cur,
                task_id,
                action="abandon",
                old_status="active",
                new_status="abandoned",
                old_task_type=task["task_type"],
                new_task_type=task["task_type"],
                detail={"abandon_reason": reason},
            )
        conn.commit()

        return {"id": task_id, "status": "abandoned"}

    finally:
        conn.close()


async def cancel_abandon(task_id: int, user_id: int, site_id: int) -> dict:
    """
    取消放弃。

    1. 验证任务归属和 status='abandoned'
    2. 恢复 status='active', 清空 abandon_reason
    3. 记录 coach_task_history
    """
    conn = _get_connection()
    try:
        assistant_id = _get_assistant_id(conn, user_id, site_id)
        task = _verify_task_ownership(
            conn, task_id, assistant_id, site_id, required_status="abandoned"
        )

        with conn.cursor() as cur:
            cur.execute("BEGIN")
            cur.execute(
                """
                UPDATE biz.coach_tasks
                SET status = 'active',
                    abandon_reason = NULL,
                    updated_at = NOW()
                WHERE id = %s
                """,
                (task_id,),
            )
            _record_history(
                cur,
                task_id,
                action="cancel_abandon",
                old_status="abandoned",
                new_status="active",
                old_task_type=task["task_type"],
                new_task_type=task["task_type"],
            )
        conn.commit()

        return {"id": task_id, "status": "active"}

    finally:
        conn.close()