"""任务 Pydantic Schemas — 支持无限嵌套子任务、裂变转交、驳回返工"""
from __future__ import annotations
import uuid
from datetime import datetime
from typing import Optional
from pydantic import BaseModel, Field, field_validator, model_validator


# ============================================================
# 请求模型
# ============================================================

class TaskCreate(BaseModel):
    """创建任务"""
    product_id: uuid.UUID = Field(..., description="所属产品ID")
    parent_task_id: uuid.UUID | None = Field(None, description="父任务ID(用于嵌套子任务/裂变分支)")
    task_name: str = Field(..., max_length=200, description="任务名称")
    assignee_id: str | None = Field(None, max_length=64, description="负责人ID(逻辑外键→老系统)")
    notify_parent_on_complete: bool = Field(False, description="完成后是否通知父任务")
    is_rework: bool = Field(False, description="是否为返工任务")
    remark: str | None = Field(None, max_length=2000, description="初始描述/交接备注")

    model_config = {"from_attributes": True}


class TaskUpdate(BaseModel):
    """更新任务"""
    task_name: str | None = Field(None, max_length=200)
    assignee_id: str | None = Field(None, max_length=64)
    status: str | None = Field(None, max_length=50, description="任务状态")
    notify_parent_on_complete: bool | None = Field(None)

    model_config = {"from_attributes": True}


class TaskCompleteRequest(BaseModel):
    """完成任务请求 — 携带转交信息（保留兼容旧版单步转交）"""
    operator_id: str | None = Field(None, max_length=64, description="操作人ID")
    next_assignee_id: str | None = Field(None, max_length=64, description="下一步任务负责人ID")
    next_task_name: str | None = Field(None, max_length=200, description="下一步任务名称")
    remark: str | None = Field(None, description="完成备注")


class SubtaskCreate(BaseModel):
    """创建子任务"""
    task_name: str = Field(..., max_length=200, description="子任务名称")
    assignee_id: str | None = Field(None, max_length=64, description="负责人ID")
    notify_parent_on_complete: bool = Field(False, description="完成后是否通知父任务")


class TaskRejectRequest(BaseModel):
    """品质驳回请求 — 驳回原因必填；异常图片【选填】
    （编号错误、工序选错等场景无需拍照举证，故不强制传图）"""
    reason: str = Field(..., min_length=1, max_length=500, description="驳回原因（必填）")
    images: list[str] = Field(
        default_factory=list, max_length=9,
        description="异常图片 URL 列表（选填，可传空数组，最多 9 张）",
    )

    @field_validator("reason", mode="before")
    @classmethod
    def _strip_reason(cls, v):
        """先 strip 再交给 min_length 校验：否则纯空格（'   '）能凑够长度绕过必填。
        顺带保证落库的 Task.reject_reason / TaskRecord.remark 不带首尾空白。
        非字符串原样返回，让 Pydantic 抛出正常的类型错误。"""
        return v.strip() if isinstance(v, str) else v

    @field_validator("images")
    @classmethod
    def _validate_images(cls, v: list[str]) -> list[str]:
        """剥离空串（前端可能提交 [''] 之类的占位），并做总长度上限校验，
        避免落库时才撞上 TaskRecord.images 的 String(4000) 上限。图片选填，允许为空。"""
        urls = [u.strip() for u in v if u and u.strip()]
        if sum(len(u) for u in urls) > 3500:
            raise ValueError("异常图片 URL 总长度超限，请减少图片数量")
        return urls


class TaskTransferBranch(BaseModel):
    """裂变分支"""
    task_name: str = Field(..., max_length=200, description="工序名称")
    assignees: list[str] = Field(
        default_factory=list, min_length=0,
        description=(
            "接收人列表。允许为空数组，但仅当 finish_directly=True 时合法——"
            "空分支不产生任何下游任务（见 TaskTransferRequest 的校验）。"
        ),
    )


class TaskTransferRequest(BaseModel):
    """完工裂变转交请求 — 支持多分支 next_tasks 和旧版单线兼容"""
    next_assignees: list[str] | None = Field(None, description="[旧版] 下一道工序接收人列表")
    next_task_name: str | None = Field(None, max_length=200, description="[旧版] 下一道工序名称")
    next_tasks: list[TaskTransferBranch] | None = Field(None, description="[新版] 多分支任务列表")
    note: str | None = Field(None, description="交接备注")
    finish_directly: bool = Field(
        False,
        description=(
            "直接完结：闭环当前任务但【不产生任何下游任务】。"
            "它只是一个任务闭环动作，【不改动】产品的 overall_status —— "
            "已出库的设备完结后依然是已出库（不入库，也不会变成「待仓库收货」）。"
            "权限：仅 SUPER_ADMIN / SUPERVISOR 可调用，其余角色 403。"
            "置 True 时忽略 next_tasks / next_assignees。"
        ),
    )

    @model_validator(mode="after")
    def _reject_silent_empty_branch(self):
        """空 assignees 分支会让「转交」静默退化成「直接完结」——任务闭环了却没人接手，
        是个丢件级隐患。想直接完结必须显式传 finish_directly=true，不能靠漏填凑合。"""
        if self.finish_directly:
            return self
        if any(not b.assignees for b in (self.next_tasks or [])):
            raise ValueError(
                "分支 assignees 不能为空；若意图是「直接完结该任务」，"
                "请改为传 finish_directly=true"
            )
        return self


class TaskRecordCreate(BaseModel):
    """任务进度记录 — 备注 + 图片"""
    remark: str = Field("", max_length=2000, description="备注文本")
    images: list[str] = Field(default_factory=list, description="图片 URL 列表")


class TaskRecordResponse(BaseModel):
    id: int
    task_id: uuid.UUID
    remark: str | None = None
    images: list[str] = []
    created_at: datetime | None = None

    model_config = {"from_attributes": True}

    @field_validator("images", mode="before")
    @classmethod
    def _parse_images(cls, v):
        """处理 DB 中 images 的 JSON 字符串 → list 反序列化（不污染 ORM 对象）"""
        import json
        if isinstance(v, str):
            try:
                return json.loads(v)
            except (json.JSONDecodeError, TypeError):
                return []
        if v is None:
            return []
        return v


# ============================================================
# 响应模型
# ============================================================

class TaskSummaryResponse(BaseModel):
    """任务摘要 — 扫码时用，不含嵌套子任务"""
    id: uuid.UUID
    product_id: uuid.UUID
    parent_task_id: uuid.UUID | None
    task_name: str
    assignee_id: str | None
    status: str
    notify_parent_on_complete: bool
    is_rework: bool = False
    task_type: str | None = None
    remark: str | None = None
    reject_reason: str | None = None
    received_at: datetime | None = None
    completed_at: datetime | None = None
    created_at: datetime
    created_by: str | None = None   # 谁创建的（从task_logs追溯）

    model_config = {"from_attributes": True}


class TaskResponse(BaseModel):
    """任务详情响应 — 递归包含所有子任务"""
    id: uuid.UUID
    product_id: uuid.UUID
    product_sn: str = ""
    product_material: str = ""
    parent_task_id: uuid.UUID | None
    task_name: str
    assignee_id: str | None
    status: str
    notify_parent_on_complete: bool
    is_rework: bool = False
    task_type: str | None = None
    remark: str | None = None
    reject_reason: str | None = None
    received_at: datetime | None = None
    completed_at: datetime | None = None
    created_at: datetime
    child_tasks: list[TaskResponse] = []
    records: list[TaskRecordResponse] = []
    created_by: str | None = None   # 谁创建的（从task_logs追溯）

    model_config = {"from_attributes": True}


class TaskCompleteResponse(BaseModel):
    """任务完成响应"""
    completed_task: TaskResponse
    next_task: TaskResponse | None = None
    message: str


class TaskTransferResponse(BaseModel):
    """裂变转交响应"""
    completed_task: TaskResponse
    created_tasks: list[TaskResponse] = []
    message: str


class TaskListResponse(BaseModel):
    """任务列表响应"""
    tasks: list[TaskResponse]
    total: int