"""Tasks CRUD 路由 + folders + channel_tasks + export(DESIGN §7.1/§7.2)。"""
from __future__ import annotations

import os
import tempfile
from pathlib import Path
from typing import Any, Optional
from uuid import UUID, uuid4

from fastapi import Depends, HTTPException
from fastapi.responses import FileResponse
from sqlalchemy import func, select, update
from starlette.background import BackgroundTask as StarletteBackgroundTask

from core.paths import to_db_path
from core.storage import NoSubtaskError, check_no_subtask, session_scope
from core.storage.models import Message, Task
from core.storage.usage_report import task_usage_aggregates as usage_aggregates
from core.storage.utils import ensure_local_task_row

from ..common import (
    CHANNEL_MIRROR_KINDS,
    STATUS_FILTERS,
    STATUS_WRITABLE,
    assert_owns_task,
    iso,
    parse_ordering,
    task_dict,
)
from ..model_gate import resolve_model_profile
from ..schemas import TaskCreateRequest, TaskPatchRequest
from ..userfiles import system_wd_names


def register_task_routes(app, *, require_user) -> None:
    @app.post("/v1/tasks", status_code=201, tags=["tasks"])
    def create_task(body: TaskCreateRequest, user_id: UUID = Depends(require_user)):
        """新建 task。

        - `name` 有值 → 作为人工标题；`working_dir` 可留空并 fallback 到 name
        - `name` 缺失/空值 → `working_dir` 必填，以“新对话”占位并在首条消息后自动命名
        - `auto_title` 仅作旧客户端兼容：显式 name + true 仍启用自动命名
        - name / working_dir 都过 validate_task_name(简单名,无 `/\\..`,非 `.` 起头,≤255)
        - 前缀嵌套(no-subtask,同 user 内)→ 409
        """
        from core.agent_builder import InvalidTaskName, resolve_workspace, validate_task_name, working_dir_from_name
        name_raw = (body.name or "").strip()
        wd_raw = (body.working_dir or "").strip()
        auto_title = bool(body.auto_title) or not name_raw
        if name_raw:
            try:
                name = validate_task_name(name_raw)
            except InvalidTaskName as e:
                raise HTTPException(400, f"name 不合法: {e}")
        else:
            if not wd_raw:
                raise HTTPException(400, "name 为空时 working_dir 必填")
            name = "新对话"

        # 兼容旧契约：显式 name 时 working_dir 留空仍 fallback 用 name。
        wd_name = wd_raw if wd_raw else name
        try:
            wd_name = validate_task_name(wd_name)
        except InvalidTaskName as e:
            raise HTTPException(400, f"working_dir 不合法: {e}")
        description = body.description.strip()
        skill = body.skill.strip()

        tid = uuid4()
        ws = resolve_workspace(None)
        fs_dir = working_dir_from_name(ws, user_id, wd_name)
        fs_dir_db = to_db_path(fs_dir)

        try:
            check_no_subtask(fs_dir_db, user_id=user_id)
        except NoSubtaskError as e:
            raise HTTPException(409, str(e))

        # 工作目录立刻建出(同 working_dir 多 task 共享,exist_ok=True)
        fs_dir.mkdir(parents=True, exist_ok=True)

        profile, model_id = resolve_model_profile(body.model_profile, user_id=user_id)
        ensure_local_task_row(
            task_id=tid, name=name, working_dir=fs_dir_db, skill=skill,
            description=description, user_id=user_id,
            model=model_id, model_profile=profile,
            auto_title_pending=auto_title,
            title_source="auto" if auto_title else "manual",
        )
        with session_scope() as s:
            row = s.execute(select(Task).where(Task.task_id == tid)).scalar_one()
        return task_dict(row, n_messages=0)

    @app.get("/v1/tasks", tags=["tasks"])
    def list_tasks_route(
        page: int = 1,
        page_size: int = 20,
        status: Optional[str] = None,
        skill: Optional[str] = None,
        working_dir: Optional[str] = None,
        q: Optional[str] = None,
        ordering: Optional[str] = None,
        run_status: Optional[str] = None,
        user_id: UUID = Depends(require_user),
    ):
        """列出当前 user 的 task,分页 + 多维筛选 + 排序。

        - `page` ≥ 1(1-based);`page_size` 1–100(超界 clamp)
        - `status` 在 active/completed/abandoned;非法值静默忽略
        - `skill` 精确匹配(空忽略)
        - `working_dir` 末段目录名(如 `水泥申报`);后端自动拼 `workspace/users/<uid>/<name>` 比对
        - `q` 模糊搜索 name + description(ILIKE,大小写不敏感)
        - `run_status` 逗号分隔,allowlist `idle/running/cancelling/error/cancelled`;非法值静默忽略
          (dev SPA 拉同 wd 活跃 task 用,通常 `running,cancelling`)
        - `ordering` DRF 风格,逗号分隔,`-field` 倒序;allowlist `created_at/updated_at/name/status`;
          非法字段静默忽略;**默认 `-updated_at`**(更新时间倒序)
        返回标准分页壳 `{page, page_size, count, results}` —— count 供前端算总页数。
        """
        # clamp + sanitize
        page = max(1, page)
        page_size = max(1, min(page_size, 100))
        status = status if status in STATUS_FILTERS else None
        skill = (skill or "").strip() or None
        wd_name = (working_dir or "").strip() or None
        q_text = (q or "").strip() or None
        rs_allowed = ("idle", "running", "cancelling", "error", "cancelled")
        run_status_set = {
            s.strip() for s in (run_status or "").split(",") if s.strip() in rs_allowed
        } or None

        # 组装 WHERE(软删除的 task 永不出现在列表;恢复见 /restore)
        # 渠道镜像 task(wechat/wecom 常驻对话)不进普通列表 —— 它们在左栏「新建任务」下
        # 做成固定卡片(GET /v1/channel_tasks),从列表排除避免重复。coalesce 兜 NULL(老 web task)。
        conditions = [
            Task.user_id == user_id,
            Task.deleted_at.is_(None),
            func.coalesce(Task.channel, "web").notin_(CHANNEL_MIRROR_KINDS),
            # 定时任务执行 task(scheduled_job_id 归属)不进普通列表;兜底 working_dir
            # LIKE 防 backfill 漏网的孤行(job 已物理删的 isolated task)
            Task.scheduled_job_id.is_(None),
            ~Task.working_dir.like("%/scheduled-%"),
        ]
        if status:
            conditions.append(Task.status == status)
        if skill:
            conditions.append(Task.skill == skill)
        if wd_name:
            # 末段 → 完整 db form。同 working_dir 多 task 共享时,这是命中入口。
            wd_db = f"workspace/users/{user_id}/{wd_name}"
            conditions.append(Task.working_dir == wd_db)
        if run_status_set:
            conditions.append(Task.run_status.in_(run_status_set))
        if q_text:
            pat = f"%{q_text}%"
            conditions.append(Task.name.ilike(pat) | Task.description.ilike(pat))

        offset = (page - 1) * page_size

        with session_scope() as s:
            cnt = s.execute(
                select(func.count()).select_from(Task).where(*conditions)
            ).scalar_one() or 0

            rows = s.execute(
                select(Task).where(*conditions)
                .order_by(*parse_ordering(ordering))
                .limit(page_size).offset(offset)
            ).scalars().all()

            tids = [r.task_id for r in rows]
            msg_counts = (
                dict(s.execute(
                    select(Message.task_id, func.count())
                    .where(Message.task_id.in_(tids))
                    .group_by(Message.task_id)
                ).all())
                if tids else {}
            )
            usage = usage_aggregates(s, tids)

        return {
            "page": page,
            "page_size": page_size,
            "count": int(cnt),
            "results": [
                task_dict(
                    r,
                    n_messages=msg_counts.get(r.task_id, 0),
                    usage=usage.get(r.task_id),
                )
                for r in rows
            ],
        }

    @app.get("/v1/channel_tasks", tags=["tasks"])
    def list_channel_tasks(user_id: UUID = Depends(require_user)):
        """渠道镜像任务(微信 / 企业微信)的绑定状态 + 常驻对话摘要 —— 前端在左栏「新建任务」
        下做成固定卡片。返回 `{ wechat: { bound: bool, task: <task_dict>|null },
                                 wecom:  { bound: bool, task: <task_dict>|null } }`,
        bound 状态由 `get_binding` / `get_wecom_userid` 判定;task 同 /v1/tasks 列表项(复用 task_dict),
        有对话则给摘要,无则 null。前端据此渲染三种卡片:未绑定(点绑定)、已绑定无对话(占位)、
        已绑定有对话(点进 + ⚙ 管理)。
        """
        from core.wechat import service as _wx

        snap = _wx.get_binding(user_id)
        wuid = _wx.get_wecom_userid(user_id)
        bound: dict[str, bool] = {
            "wechat": bool(snap and snap.status == "active"),
            "wecom": bool(wuid),
        }
        tids: dict[str, Optional[UUID]] = {
            "wechat": snap.chat_task_id if snap and snap.status == "active" else None,
            "wecom": _wx.get_wecom_chat_task(user_id),
        }
        wanted = [t for t in tids.values() if t is not None]
        tasks: dict[str, Optional[dict]] = {"wechat": None, "wecom": None}
        if wanted:
            with session_scope() as s:
                rows = {
                    r.task_id: r
                    for r in s.execute(
                        select(Task).where(
                            Task.task_id.in_(wanted),
                            Task.user_id == user_id,
                            Task.deleted_at.is_(None),
                        )
                    ).scalars().all()
                }
                msg_counts = dict(
                    s.execute(
                        select(Message.task_id, func.count())
                        .where(Message.task_id.in_(list(rows.keys())))
                        .group_by(Message.task_id)
                    ).all()
                ) if rows else {}
                usage = usage_aggregates(s, list(rows.keys()))
                for kind, tid in tids.items():
                    row = rows.get(tid) if tid else None
                    if row is not None:
                        tasks[kind] = task_dict(
                            row,
                            n_messages=msg_counts.get(row.task_id, 0),
                            usage=usage.get(row.task_id),
                        )
        # 按渠道返回 { bound, task }
        return {
            "wechat": {"bound": bound["wechat"], "task": tasks["wechat"]},
            "wecom":  {"bound": bound["wecom"],  "task": tasks["wecom"]},
        }

    @app.get("/v1/tasks/{task_id}", tags=["tasks"])
    def get_task(task_id: str, user_id: UUID = Depends(require_user)):
        """单 task meta(不含 messages;走 /messages 拿)。跨 user → 404。

        额外带上下文压力字段(仅详情端点,列表不加 —— 每 task 一条 sum 聚合,列表
        100 行×聚合不值得):`context_window_chars`(当前窗口体量,idx>=base 的
        payload 字节和)、`context_limit_chars`(reliable_context×2.5 折算容量)、
        `context_pressure`(前者/后者,0-1+)、`context_folds`(折叠次数,=
        usage_events kind='context_fold' 计数)。前端头部压缩指示环用。
        """
        from sqlalchemy import Text as SAText, cast as sa_cast

        from core.context import CHARS_PER_TOKEN
        from core.storage.models import UsageEvent

        try:
            tid = UUID(task_id)
        except ValueError:
            raise HTTPException(404, f"invalid task id: {task_id!r}")
        with session_scope() as s:
            row = s.execute(
                select(Task).where(Task.task_id == tid, Task.user_id == user_id)
            ).scalar_one_or_none()
            if row is None:
                raise HTTPException(404, f"task not found: {tid}")
            n = s.execute(
                select(func.count()).select_from(Message).where(Message.task_id == tid)
            ).scalar_one()
            usage = usage_aggregates(s, [tid])
            window_chars = s.execute(
                select(func.coalesce(func.sum(func.length(sa_cast(Message.payload, SAText))), 0))
                .where(Message.task_id == tid, Message.idx >= (row.context_base_idx or 0))
            ).scalar_one()
            folds = s.execute(
                select(func.count()).select_from(UsageEvent)
                .where(UsageEvent.task_id == tid, UsageEvent.kind == "context_fold")
            ).scalar_one()
            d = task_dict(row, n_messages=n, usage=usage.get(tid))
        # 容量按 task 当前模型折算;模型档案读不出(profile 已下线等)→ 字段置 None,
        # 前端画灰环,不 500。
        limit_chars = None
        try:
            from core.agent_builder import load_config
            from core.capabilities import ModelCapabilities
            from core.paths import ROOT
            cfg = load_config()
            profile = d.get("model_profile") or cfg["default_model"]
            caps = ModelCapabilities.load(profile, ROOT / cfg["models_dir"])
            limit_chars = int(caps.reliable_context * CHARS_PER_TOKEN)
        except Exception:
            pass
        d["context_window_chars"] = int(window_chars)
        d["context_limit_chars"] = limit_chars
        d["context_pressure"] = (
            round(int(window_chars) / limit_chars, 4) if limit_chars else None
        )
        d["context_folds"] = int(folds)
        return d

    @app.get("/v1/folders", tags=["folders"])
    def list_folders(user_id: UUID = Depends(require_user)):
        """列出当前 user 的工作目录(`workspace/users/<uid>/` 下非 dotfile 子目录)。
        供新建 task 时自动补全 / 选已有目录用。FS 是 source of truth(也含手动创建
        但还无关联 task 的目录)。每项带 n_tasks(关联 task 数)+ last_used(最近使用 ISO)。
        排序:有 last_used 的按降序,无 last_used 的排最后,同列 by name asc。
        """
        from core.agent_builder import resolve_workspace, user_root
        ws = resolve_workspace(None)
        root = user_root(ws, user_id)

        folder_names: list[str] = []
        if root.is_dir():
            for p in sorted(root.iterdir(), key=lambda x: x.name.lower()):
                if p.is_dir() and not p.name.startswith("."):
                    folder_names.append(p.name)
        # 系统工作目录(定时/渠道)不进候选 —— 新任务不该落到它们里面
        hidden = system_wd_names(user_id) if folder_names else set()
        folder_names = [n for n in folder_names if n not in hidden]

        folders: list[dict] = []
        if folder_names:
            with session_scope() as s:
                for name in folder_names:
                    db_form = f"workspace/users/{user_id}/{name}"
                    stat = s.execute(
                        select(func.count(), func.max(Task.updated_at))
                        .where(
                            Task.user_id == user_id,
                            Task.working_dir == db_form,
                            Task.deleted_at.is_(None),
                        )
                    ).first()
                    n = int((stat[0] if stat else 0) or 0)
                    lu = stat[1] if stat else None
                    folders.append({
                        "name": name,
                        "n_tasks": n,
                        "last_used": iso(lu),
                    })

        folders.sort(key=lambda f: f["name"])
        folders.sort(key=lambda f: f["last_used"] or "", reverse=True)
        return {"folders": folders}

    @app.delete("/v1/tasks/{task_id}", status_code=204, tags=["tasks"])
    def delete_task(task_id: str, user_id: UUID = Depends(require_user)):
        """软删除:置 deleted_at=now(),从任务列表隐藏。

        DB 行 / messages / usage_events(原 CASCADE 不再触发)及工作目录文件全部保留
        —— 留作训练语料,且可经 POST /v1/tasks/{id}/restore 恢复。不动任何磁盘文件。
        已软删的再次调用幂等返回 204。跨 user / 不存在 → 404。
        """
        try:
            tid = UUID(task_id)
        except ValueError:
            raise HTTPException(404, f"invalid task id: {task_id!r}")
        with session_scope() as s:
            row = s.execute(
                select(Task.deleted_at).where(
                    Task.task_id == tid, Task.user_id == user_id,
                )
            ).first()
            if row is None:
                raise HTTPException(404, f"task not found: {tid}")
            if row.deleted_at is None:
                s.execute(
                    update(Task)
                    .where(Task.task_id == tid, Task.user_id == user_id)
                    .values(deleted_at=func.now())
                )
        return None  # 204

    @app.post("/v1/tasks/{task_id}/restore", tags=["tasks"])
    def restore_task(task_id: str, user_id: UUID = Depends(require_user)):
        """恢复软删除的 task(置 deleted_at=NULL),重新出现在列表。

        未软删的幂等成功。跨 user / 不存在 → 404。
        """
        try:
            tid = UUID(task_id)
        except ValueError:
            raise HTTPException(404, f"invalid task id: {task_id!r}")
        with session_scope() as s:
            row = s.execute(
                select(Task).where(Task.task_id == tid, Task.user_id == user_id)
            ).scalar_one_or_none()
            if row is None:
                raise HTTPException(404, f"task not found: {tid}")
            row.deleted_at = None  # ORM 脏标记,session_scope 提交时落库
            n = s.execute(
                select(func.count()).select_from(Message).where(Message.task_id == tid)
            ).scalar_one()
            usage = usage_aggregates(s, [tid])
            # 序列化必须在 session 内:updated_at 是 server-side onupdate,flush 后被
            # 标记 expired,出了 session 再读会 DetachedInstanceError(真软删过的恢复
            # 路径 500;幂等路径无脏标记所以此前没暴露 —— test_web_routes_db 抓出)。
            s.flush()
            s.refresh(row)
            d = task_dict(row, n_messages=n, usage=usage.get(tid))
        return d

    @app.patch("/v1/tasks/{task_id}", tags=["tasks"])
    def patch_task(
        task_id: str,
        body: TaskPatchRequest,
        user_id: UUID = Depends(require_user),
    ):
        """更新 task 字段。`status` 仅允许 completed/abandoned(active 走 CLI 切回)。"""
        try:
            tid = UUID(task_id)
        except ValueError:
            raise HTTPException(404, f"invalid task id: {task_id!r}")
        updates: dict[str, Any] = {}
        if body.status is not None:
            if body.status not in STATUS_WRITABLE:
                raise HTTPException(
                    400, f"invalid status {body.status!r}; allowed: {STATUS_WRITABLE}"
                )
            updates["status"] = body.status
        if body.description is not None:
            updates["description"] = body.description
        if body.skill is not None:
            updates["skill"] = body.skill
        if body.name is not None:
            from core.agent_builder import InvalidTaskName, validate_task_name
            try:
                updates["name"] = validate_task_name(body.name)
            except InvalidTaskName as e:
                raise HTTPException(400, f"name 不合法: {e}")
            # 人工命名优先级最高：即使自动标题调用已在途，最终 UPDATE 也会因
            # pending=False 条件失配而放弃，绝不覆盖用户刚改好的名称。
            updates["auto_title_pending"] = False
            updates["title_source"] = "manual"
        if body.model_profile is not None:
            # 切模型:校验后双列同更(profile + model_id)。下条 send 才生效 — 当前
            # in-flight run 不受影响(build_agent resume 时下次重读)。档外模型 → 403。
            profile, model_id = resolve_model_profile(body.model_profile, user_id=user_id)
            updates["model_profile"] = profile
            updates["model"] = model_id
        if not updates:
            raise HTTPException(400, "no fields to update")
        with session_scope() as s:
            result = s.execute(
                update(Task)
                .where(Task.task_id == tid, Task.user_id == user_id)
                .values(**updates)
            )
            if result.rowcount == 0:
                raise HTTPException(404, f"task not found: {tid}")
            row = s.execute(select(Task).where(Task.task_id == tid)).scalar_one()
            n = s.execute(
                select(func.count()).select_from(Message).where(Message.task_id == tid)
            ).scalar_one()
            usage = usage_aggregates(s, [tid])
        return task_dict(row, n_messages=n, usage=usage.get(tid))

    @app.get("/v1/tasks/{task_id}/export", tags=["export"])
    def export_task(task_id: str, user_id: UUID = Depends(require_user)):
        """导出对话为 .docx,临时文件下载完后 BackgroundTask 删 tmp。"""
        try:
            tid = UUID(task_id)
        except ValueError:
            raise HTTPException(404, f"invalid task id: {task_id!r}")
        with session_scope() as s:
            assert_owns_task(s, tid, user_id)
            has_msg = s.execute(
                select(Message.message_id).where(Message.task_id == tid).limit(1)
            ).first()
        if not has_msg:
            raise HTTPException(400, "no messages to export")

        fd, tmp_str = tempfile.mkstemp(suffix=".docx", prefix="zcbot-export-")
        os.close(fd)
        tmp_path = Path(tmp_str)
        try:
            from core.export_docx import export_chat_to_docx
            export_chat_to_docx(tid, out_path=tmp_path)
        except Exception as e:
            tmp_path.unlink(missing_ok=True)
            raise HTTPException(500, f"export failed: {type(e).__name__}: {e}")

        return FileResponse(
            path=str(tmp_path),
            media_type="application/vnd.openxmlformats-officedocument.wordprocessingml.document",
            filename=f"chat_{str(tid)[:8]}.docx",
            background=StarletteBackgroundTask(tmp_path.unlink, missing_ok=True),
        )