"""Asset 子域 Router。

外部系统限界上下文的适配器资产管理 API，覆盖资产 CRUD / 校验 / 预览 /
引用 / 生成预览。所有端点通过 ``create_use_cases_from_db`` 装配 use_cases，
经 ``asset_service`` 端口调用用例。

Request Schema 与 Input DTO 不共享类，Router 内显式构造 DTO，操作人字段由
current_user.uid 填充。``content`` 字段在 Request Schema 中为 base64 字符串，
Router 内解码为 bytes；``size`` 与 ``checksum`` 由 service 根据 ``content``
统一计算，不在 Router 侧透传，避免与 service 计算结果不一致。
"""

from __future__ import annotations

import base64
import binascii
from datetime import datetime
from typing import Any

from fastapi import (
    APIRouter,
    Depends,
    File,
    Form,
    Path,
    Query,
    UploadFile,
)
from pydantic import (
    BaseModel,
    ConfigDict,
    Field,
    field_validator,
    model_validator,
)
from sqlalchemy.ext.asyncio import AsyncSession
from yuxi.external_systems.exceptions import ExternalSystemError
from yuxi.external_systems.infrastructure.container import create_use_cases_from_db
from yuxi.external_systems.use_cases.dto.asset import (
    CreateAssetInput,
    DeleteAssetInput,
    GeneratePreviewInput,
    GetAssetByChecksumInput,
    GetAssetInput,
    GetAssetReferencesInput,
    ListAssetsInput,
    PreviewAssetInput,
    ProbeAssetInput,
    UpdateAssetInput,
    ValidateAssetInput,
)
from yuxi.storage.postgres.models_business import User

from server.utils.auth_middleware import get_admin_user, get_db, get_required_user

asset_router = APIRouter(prefix="/assets", tags=["external-systems-asset"])


# ---------------- Request Schemas ----------------


def _validate_base64_content(value: str) -> str:
    """校验 base64 编码字符串，非法时抛 ValueError（由 Pydantic 映射为 422）。"""
    try:
        base64.b64decode(value, validate=True)
    except (binascii.Error, ValueError) as exc:
        raise ValueError("content 必须是合法的 base64 编码") from exc
    return value


class CreateAssetRequest(BaseModel):
    """创建资产请求体。字段对齐 ``CreateAssetInput``（不含 size、checksum 与 created_by）。

    ``content`` 为 base64 编码的字符串，Router 内解码为 bytes；
    ``size`` 与 ``checksum`` 由 service 根据 ``content`` 统一计算。
    """

    model_config = ConfigDict(frozen=True)

    adapter_type: str = Field(..., max_length=32)
    asset_type: str = Field(..., max_length=32)
    name: str = Field(..., min_length=1, max_length=128)
    content: str = Field(..., min_length=1)

    @field_validator("content")
    @classmethod
    def validate_content(cls, v: str) -> str:
        return _validate_base64_content(v)


class UpdateAssetRequest(BaseModel):
    """更新资产请求体。字段对齐 ``UpdateAssetInput``（不含 id、size、checksum 与 updated_by）。

    ``content`` 为 base64 编码的字符串，Router 内解码为 bytes；
    ``size`` 与 ``checksum`` 由 service 根据 ``content`` 统一计算，
    不接受客户端单独传入 ``checksum``，避免与实际内容不一致。
    仅透传客户端显式设置的字段。
    """

    model_config = ConfigDict(frozen=True)

    name: str | None = Field(default=None, min_length=1, max_length=128)
    status: str | None = Field(default=None, max_length=32)
    status_message: str | None = None
    content: str | None = Field(default=None, min_length=1)

    @field_validator("content")
    @classmethod
    def validate_content(cls, v: str | None) -> str | None:
        if v is None:
            return v
        return _validate_base64_content(v)


class BatchDeleteAssetsRequest(BaseModel):
    """批量删除资产请求体。"""

    model_config = ConfigDict(frozen=True)

    asset_ids: list[int] = Field(..., min_length=1, max_length=100)


class BatchValidateAssetsRequest(BaseModel):
    """批量校验资产请求体。"""

    model_config = ConfigDict(frozen=True)

    asset_ids: list[int] = Field(..., min_length=1, max_length=100)


class ProbeAssetRequest(BaseModel):
    """资产探测请求体。``content`` 为 base64 编码字符串，与 ``url`` 二选一。"""

    model_config = ConfigDict(frozen=True)

    adapter_type: str = Field(..., max_length=32)
    source_type: str = Field(..., max_length=32)
    content: str | None = Field(default=None, min_length=1)
    url: str | None = Field(default=None, max_length=2048)

    @field_validator("content")
    @classmethod
    def validate_content(cls, v: str | None) -> str | None:
        if v is None:
            return v
        return _validate_base64_content(v)

    @model_validator(mode="after")
    def validate_source(self) -> ProbeAssetRequest:
        if self.content is None and self.url is None:
            raise ValueError("必须提供 url 或 content")
        if self.content is not None and self.url is not None:
            raise ValueError("url 与 content 不能同时提供")
        return self


# ---------------- Endpoints ----------------


@asset_router.get("", response_model=dict)
async def list_assets(
    limit: int = Query(100, ge=1, le=500),
    offset: int = Query(0, ge=0),
    adapter_type: str | None = Query(None, max_length=32),
    asset_type: str | None = Query(None, max_length=32),
    status: str | None = Query(None, max_length=32),
    keyword: str | None = Query(None, max_length=128),
    start_time: datetime | None = Query(None, description="创建时间起始（UTC ISO 8601）"),
    end_time: datetime | None = Query(None, description="创建时间结束（UTC ISO 8601）"),
    created_by: str | None = Query(None, max_length=64, description="按创建人过滤"),
    db: AsyncSession = Depends(get_db),
    current_user: User = Depends(get_required_user),
) -> dict[str, Any]:
    """分页列出适配器资产。"""
    use_cases = create_use_cases_from_db(db)
    input_dto = ListAssetsInput(
        page=offset // limit + 1,
        page_size=limit,
        adapter_type=adapter_type,
        asset_type=asset_type,
        status=status,
        keyword=keyword,
        start_time=start_time,
        end_time=end_time,
        created_by=created_by,
    )
    output = await use_cases.asset_service.list_assets(input_dto)
    return {"success": True, "data": output.model_dump()}


@asset_router.post("", response_model=dict)
async def create_asset(
    payload: CreateAssetRequest,
    db: AsyncSession = Depends(get_db),
    current_user: User = Depends(get_admin_user),
) -> dict[str, Any]:
    """创建适配器资产。``content`` 为 base64 字符串，解码后交由 service 计算 size 与 checksum。"""
    use_cases = create_use_cases_from_db(db)
    content = base64.b64decode(payload.content)
    input_dto = CreateAssetInput(
        adapter_type=payload.adapter_type,
        asset_type=payload.asset_type,
        name=payload.name,
        content=content,
        created_by=current_user.uid,
    )
    output = await use_cases.asset_service.create_asset(input_dto)
    return {"success": True, "data": output.model_dump()}


@asset_router.get("/stats", response_model=dict)
async def get_asset_stats(
    db: AsyncSession = Depends(get_db),
    current_user: User = Depends(get_required_user),
) -> dict[str, Any]:
    """查询资产统计（按适配器类型、资产类型、状态分组）。"""
    use_cases = create_use_cases_from_db(db)
    output = await use_cases.asset_service.get_asset_stats()
    return {"success": True, "data": output.model_dump()}


@asset_router.get("/by-checksum/{checksum}", response_model=dict)
async def get_asset_by_checksum(
    checksum: str = Path(
        ...,
        min_length=64,
        max_length=64,
        pattern=r"^[0-9a-f]{64}$",
        description="SHA-256 checksum（64 位十六进制字符串）",
    ),
    db: AsyncSession = Depends(get_db),
    current_user: User = Depends(get_required_user),
) -> dict[str, Any]:
    """按 SHA-256 checksum 查询资产（上传去重检查）。资产不存在时 data 为 null。"""
    use_cases = create_use_cases_from_db(db)
    input_dto = GetAssetByChecksumInput(checksum=checksum)
    output = await use_cases.asset_service.get_asset_by_checksum(input_dto)
    return {"success": True, "data": output.model_dump() if output else None}


@asset_router.post("/batch-upload", response_model=dict)
async def batch_upload_assets(
    adapter_type: str = Form(..., max_length=32),
    asset_type: str = Form(..., max_length=32),
    files: list[UploadFile] = File(..., min_length=1, max_length=100),
    db: AsyncSession = Depends(get_db),
    current_user: User = Depends(get_admin_user),
) -> dict[str, Any]:
    """批量上传资产文件（multipart/form-data），允许部分成功。

    所有文件共享一个 ``adapter_type`` 与 ``asset_type``，适用于批量上传同类型资产场景。
    单次最多 100 个文件，每个文件独立创建，失败项记录 filename 与 reason。
    """
    use_cases = create_use_cases_from_db(db)
    uploaded: list[dict[str, Any]] = []
    failed: list[dict[str, str]] = []
    for file in files:
        try:
            content = await file.read()
            input_dto = CreateAssetInput(
                adapter_type=adapter_type,
                asset_type=asset_type,
                name=file.filename or "unnamed",
                content=content,
                created_by=current_user.uid,
            )
            output = await use_cases.asset_service.create_asset(input_dto)
            uploaded.append(output.model_dump())
        except ExternalSystemError as exc:
            failed.append({"filename": file.filename or "unnamed", "reason": str(exc)})
    return {"success": True, "data": {"uploaded": uploaded, "failed": failed}}


@asset_router.post("/batch-delete", response_model=dict)
async def batch_delete_assets(
    payload: BatchDeleteAssetsRequest,
    db: AsyncSession = Depends(get_db),
    current_user: User = Depends(get_admin_user),
) -> dict[str, Any]:
    """批量删除资产（软删除），允许部分成功。

    循环调用 ``delete_asset`` 保证每个资产的引用检查完整执行。
    """
    use_cases = create_use_cases_from_db(db)
    deleted_count = 0
    failed: list[dict[str, Any]] = []
    for asset_id in payload.asset_ids:
        try:
            input_dto = DeleteAssetInput(id=asset_id, user=current_user.uid)
            await use_cases.asset_service.delete_asset(input_dto)
            deleted_count += 1
        except ExternalSystemError as exc:
            failed.append({"asset_id": asset_id, "reason": str(exc)})
    return {"success": True, "data": {"deleted_count": deleted_count, "failed": failed}}


@asset_router.post("/batch-validate", response_model=dict)
async def batch_validate_assets(
    payload: BatchValidateAssetsRequest,
    db: AsyncSession = Depends(get_db),
    current_user: User = Depends(get_admin_user),
) -> dict[str, Any]:
    """批量校验资产并更新状态，允许部分成功。"""
    use_cases = create_use_cases_from_db(db)
    validated: list[dict[str, Any]] = []
    failed: list[dict[str, Any]] = []
    for asset_id in payload.asset_ids:
        try:
            input_dto = ValidateAssetInput(id=asset_id, user=current_user.uid)
            output = await use_cases.asset_service.validate_asset(input_dto)
            validated.append(output.model_dump())
        except ExternalSystemError as exc:
            failed.append({"asset_id": asset_id, "reason": str(exc)})
    return {"success": True, "data": {"validated": validated, "failed": failed}}


@asset_router.post("/probe", response_model=dict)
async def probe_asset(
    payload: ProbeAssetRequest,
    db: AsyncSession = Depends(get_db),
    current_user: User = Depends(get_admin_user),
) -> dict[str, Any]:
    """探测资产内容（URL 或 base64 内容），返回适配器解析的摘要，不保存资产。"""
    use_cases = create_use_cases_from_db(db)
    input_dto = ProbeAssetInput(
        adapter_type=payload.adapter_type,
        source_type=payload.source_type,
        content=payload.content,
        url=payload.url,
    )
    output = await use_cases.asset_service.probe_asset(input_dto)
    return {"success": True, "data": output.model_dump()}


@asset_router.get("/{asset_id}", response_model=dict)
async def get_asset(
    asset_id: int = Path(ge=1),
    db: AsyncSession = Depends(get_db),
    current_user: User = Depends(get_required_user),
) -> dict[str, Any]:
    """获取资产详情。"""
    use_cases = create_use_cases_from_db(db)
    input_dto = GetAssetInput(id=asset_id)
    output = await use_cases.asset_service.get_asset(input_dto)
    return {"success": True, "data": output.model_dump()}


@asset_router.put("/{asset_id}", response_model=dict)
async def update_asset(
    payload: UpdateAssetRequest,
    asset_id: int = Path(ge=1),
    db: AsyncSession = Depends(get_db),
    current_user: User = Depends(get_admin_user),
) -> dict[str, Any]:
    """更新资产。``content`` 为 base64 字符串，解码后交由 service 计算 size 与 checksum。仅透传显式设置的字段。"""
    use_cases = create_use_cases_from_db(db)
    data = payload.model_dump(exclude_unset=True)
    content_b64 = data.pop("content", None)
    if content_b64 is not None:
        data["content"] = base64.b64decode(content_b64)
    input_dto = UpdateAssetInput(
        id=asset_id,
        updated_by=current_user.uid,
        **data,
    )
    output = await use_cases.asset_service.update_asset(input_dto)
    return {"success": True, "data": output.model_dump()}


@asset_router.delete("/{asset_id}", response_model=dict)
async def delete_asset(
    asset_id: int = Path(ge=1),
    db: AsyncSession = Depends(get_db),
    current_user: User = Depends(get_admin_user),
) -> dict[str, Any]:
    """删除资产。"""
    use_cases = create_use_cases_from_db(db)
    input_dto = DeleteAssetInput(id=asset_id, user=current_user.uid)
    output = await use_cases.asset_service.delete_asset(input_dto)
    return {"success": True, "data": output.model_dump()}


@asset_router.post("/{asset_id}/validate", response_model=dict)
async def validate_asset(
    asset_id: int = Path(ge=1),
    db: AsyncSession = Depends(get_db),
    current_user: User = Depends(get_admin_user),
) -> dict[str, Any]:
    """校验资产。"""
    use_cases = create_use_cases_from_db(db)
    input_dto = ValidateAssetInput(id=asset_id, user=current_user.uid)
    output = await use_cases.asset_service.validate_asset(input_dto)
    return {"success": True, "data": output.model_dump()}


@asset_router.get("/{asset_id}/preview", response_model=dict)
async def preview_asset(
    asset_id: int = Path(ge=1),
    max_lines: int = Query(200, ge=1, le=10000),
    db: AsyncSession = Depends(get_db),
    current_user: User = Depends(get_required_user),
) -> dict[str, Any]:
    """预览资产内容（适配器视角的结构化摘要）。

    调用适配器的 ``preview_asset`` 能力，返回适配器解析的摘要（如 OpenAPI 的 endpoint 列表）。
    与 ``generate_preview`` 的区别：本端点调用外部适配器获取结构化摘要，
    ``generate_preview`` 仅本地解码内容并截取前 N 行原始文本。
    """
    use_cases = create_use_cases_from_db(db)
    input_dto = PreviewAssetInput(id=asset_id, max_lines=max_lines)
    output = await use_cases.asset_service.preview_asset(input_dto)
    return {"success": True, "data": output.model_dump()}


@asset_router.get("/{asset_id}/generate-preview", response_model=dict)
async def generate_preview(
    asset_id: int = Path(ge=1),
    max_lines: int = Query(200, ge=1, le=10000),
    db: AsyncSession = Depends(get_db),
    current_user: User = Depends(get_required_user),
) -> dict[str, Any]:
    """生成资产文本预览（本地解码内容并截取前 N 行）。

    不调用外部适配器，仅本地解码内容并截取前 N 行，适用于查看资产原始文本内容。
    与 ``preview_asset`` 的区别：本端点不调用外部适配器，仅返回原始文本前 N 行；
    ``preview_asset`` 调用适配器获取结构化摘要。
    """
    use_cases = create_use_cases_from_db(db)
    input_dto = GeneratePreviewInput(id=asset_id, max_lines=max_lines)
    output = await use_cases.asset_service.generate_preview(input_dto)
    return {"success": True, "data": output.model_dump()}


@asset_router.get("/{asset_id}/references", response_model=dict)
async def get_asset_references(
    asset_id: int = Path(ge=1),
    db: AsyncSession = Depends(get_db),
    current_user: User = Depends(get_required_user),
) -> dict[str, Any]:
    """获取资产引用（关联的系统与工具）。"""
    use_cases = create_use_cases_from_db(db)
    input_dto = GetAssetReferencesInput(id=asset_id)
    output = await use_cases.asset_service.get_asset_references(input_dto)
    return {"success": True, "data": output.model_dump()}