"""视频复刻:参考视频 + 商品图/人物图 → Seedance 换商品或换角色。

不新建任务类型、不接检测/抠图。提交仍走 submit_free_video,只把
feature=video_replace 和 replace_mode 写进 payload,提示词由后端写死。
"""
from __future__ import annotations

import uuid

from django.db.models import Q

from apps.assets.models import Asset, Model
from apps.products.models import Product

from .free_video import HIGH_RES_MODEL, serialize_free_video_task, submit_free_video
from .media_probe import REF_DURATION_MAX

FEATURE = "video_replace"
REPLACE_MODES = {"product", "character"}
MAX_IMAGES = 9
LEGACY_PROMPT_PREFIX = "[视频复刻]"

PRODUCT_PROMPT = (
    "使用@参考视频作为镜头、节奏与口播氛围基准，"
    "将画面中需要替换的原商品完整替换为@目标商品的外观。"
    "保留参考视频的人物、场景、镜头运动、剪辑节奏与口播氛围，"
    "商品外观、材质、包装必须与参考图一致，不要改变原片构图和人物表演。"
)
CHARACTER_PROMPT = (
    "使用@参考视频作为镜头、节奏与口播氛围基准，"
    "将画面中需要替换的原人物完整替换为@目标角色。"
    "保留参考视频的商品、场景、镜头运动、剪辑节奏与口播氛围，"
    "角色五官、发型、体态必须与参考图一致，不要改变原片构图和商品展示。"
)


def is_video_replace_task(task) -> bool:
    payload = task.request_payload or {}
    if payload.get("feature") == FEATURE:
        return True
    return str(payload.get("prompt") or "").startswith(LEGACY_PROMPT_PREFIX)


def video_replace_q() -> Q:
    return Q(request_payload__feature=FEATURE) | Q(request_payload__prompt__startswith=LEGACY_PROMPT_PREFIX)


def serialize_video_replace_task(task, *, include_deleted_assets: bool = False) -> dict:
    data = serialize_free_video_task(task, include_deleted_assets=include_deleted_assets)
    payload = task.request_payload or {}
    replace_mode = payload.get("replace_mode") or _legacy_replace_mode(payload.get("prompt") or "")
    data.update({
        "feature": FEATURE,
        "replace_mode": replace_mode,
        "subject_name": payload.get("subject_name") or "",
        "subject_source": payload.get("subject_source") or "",
        "product_id": payload.get("product_id") or "",
        "model_id": payload.get("model_id") or "",
    })
    return data


def submit_video_replace(*, team, user, params: dict):
    """校验素材 → 套提示词 → 复用 free_video 提交。失败抛 ValueError。"""
    replace_mode = str(params.get("replace_mode") or "").strip()
    if replace_mode not in REPLACE_MODES:
        raise ValueError("请选择替换商品或替换角色")

    product_id = _optional_uuid(params.get("product_id"), "商品")
    model_id = _optional_uuid(params.get("model_id"), "角色")
    image_ids = _uuid_list(params.get("image_asset_ids"), "参考图")
    has_product = product_id is not None
    has_model = model_id is not None
    has_temp = bool(image_ids)

    if replace_mode == "product":
        if has_model:
            raise ValueError("商品复刻请选择商品，不要同时选择角色")
        if has_product and has_temp:
            raise ValueError("请从商品库选择，或临时上传商品图，不要混用")
        if not has_product and not has_temp:
            raise ValueError("请选择商品或上传商品参考图")
    else:
        if has_product:
            raise ValueError("角色复刻请选择角色，不要同时选择商品")
        if has_model and has_temp:
            raise ValueError("请从人物库选择，或临时上传角色图，不要混用")
        if not has_model and not has_temp:
            raise ValueError("请选择角色或上传角色参考图")

    video = _team_asset(team, params.get("video_asset_id"), kind=Asset.Type.VIDEO, label="参考视频")
    video_seconds = _asset_duration_seconds(video)
    if video_seconds > REF_DURATION_MAX:
        raise ValueError("参考视频不能超过 15 秒，请剪短后重试")

    if has_product:
        subject_name, image_refs, subject_source = _product_library_refs(team, product_id)
    elif has_model:
        subject_name, image_refs, subject_source = _character_library_refs(team, model_id)
    else:
        noun = "商品" if replace_mode == "product" else "角色"
        subject_name, image_refs, subject_source = _temporary_image_refs(team, image_ids, noun=noun)

    prompt = PRODUCT_PROMPT if replace_mode == "product" else CHARACTER_PROMPT
    duration = _output_duration(params.get("duration"), video_seconds)
    references = [
        _owned_ref(video, kind="video", role="reference_video", label="参考视频"),
        *image_refs,
    ]
    return submit_free_video(
        team=team,
        user=user,
        params={
            "prompt": prompt,
            "mode": "universal",
            "model": str(params.get("model") or HIGH_RES_MODEL),
            "aspect_ratio": str(params.get("aspect_ratio") or "9:16"),
            "resolution": str(params.get("resolution") or "720p"),
            "duration": duration,
            "seed": params.get("seed", -1),
            "generate_audio": True,
            "references": references,
            "feature": FEATURE,
            "extra_payload": {
                "replace_mode": replace_mode,
                "subject_name": subject_name,
                "subject_source": subject_source,
                "product_id": str(product_id) if product_id else "",
                "model_id": str(model_id) if model_id else "",
            },
        },
    )


def _legacy_replace_mode(prompt: str) -> str:
    return "character" if prompt.startswith("[视频复刻·角色]") else "product"


def _optional_uuid(value, label: str):
    text = str(value or "").strip()
    if not text:
        return None
    try:
        return uuid.UUID(text)
    except (TypeError, ValueError) as exc:
        raise ValueError(f"{label}无效") from exc


def _uuid_list(value, label: str) -> list:
    if value in (None, ""):
        return []
    if not isinstance(value, (list, tuple)):
        raise ValueError(f"{label}格式无效")
    if len(value) > MAX_IMAGES:
        raise ValueError(f"{label}最多 {MAX_IMAGES} 张")
    seen = set()
    out = []
    for item in value:
        parsed = _optional_uuid(item, label)
        if parsed is None or parsed in seen:
            continue
        seen.add(parsed)
        out.append(parsed)
    return out


def _team_asset(team, asset_id, *, kind: str, label: str) -> Asset:
    parsed = _optional_uuid(asset_id, label)
    if parsed is None:
        raise ValueError(f"请先上传{label}")
    asset = Asset.objects.filter(id=parsed, team=team, is_deleted=False, purged_at__isnull=True).first()
    if asset is None:
        raise ValueError(f"{label}不存在或已被删除")
    if asset.asset_type != kind:
        raise ValueError(f"{label}类型不正确")
    return asset


def _asset_duration_seconds(asset: Asset) -> float:
    primary = asset.files.filter(is_primary=True).first() or asset.files.first()
    if primary is None or not primary.duration_ms:
        return 0.0
    return primary.duration_ms / 1000.0


def _output_duration(requested, video_seconds: float) -> int:
    try:
        value = int(requested) if requested not in (None, "") else 0
    except (TypeError, ValueError):
        value = 0
    if value:
        return min(15, max(4, value))
    if video_seconds:
        return min(15, max(4, int(round(video_seconds))))
    return 15


def _owned_ref(asset: Asset, *, kind: str, role: str, label: str) -> dict:
    from .services import _asset_preview_url

    url = _asset_preview_url(asset)
    if not url:
        raise ValueError(f"「{label}」没有可用文件")
    ref = {
        "url": url,
        "type": kind,
        "role": role,
        "label": label,
        "source": "upload",
        "asset_id": str(asset.id),
    }
    seconds = _asset_duration_seconds(asset)
    if seconds:
        ref["duration"] = seconds
    return ref


def _library_image_ref(asset: Asset, *, team, label: str) -> dict:
    from .services import _asset_preview_url, _seedance_ref_url

    if asset.team_id == team.id and not asset.is_deleted:
        return {
            "url": _asset_preview_url(asset) or "",
            "type": "image",
            "role": "reference_image",
            "label": label,
            "source": "asset",
            "asset_id": str(asset.id),
        }
    raw = _asset_preview_url(asset)
    url = _seedance_ref_url(raw, asset.review_status, asset.review_remote_id)
    if not url:
        raise ValueError(f"「{label}」没有可用文件")
    return {
        "url": url,
        "type": "image",
        "role": "reference_image",
        "label": label,
        "source": "upload",
        "asset_id": str(asset.id),
    }


def _product_library_refs(team, product_id: uuid.UUID) -> tuple[str, list, str]:
    product = (
        Product.objects.filter(id=product_id, team=team, purged_at__isnull=True, status=Product.Status.ACTIVE)
        .select_related("cover_asset")
        .prefetch_related("images__asset")
        .first()
    )
    if product is None:
        raise ValueError("商品不存在或已被删除")
    assets = []
    seen = set()
    for image in product.images.all():
        asset = image.asset
        if asset is None or asset.id in seen or asset.is_deleted:
            continue
        seen.add(asset.id)
        assets.append(asset)
        if len(assets) >= MAX_IMAGES:
            break
    if not assets and product.cover_asset_id and not product.cover_asset.is_deleted:
        assets.append(product.cover_asset)
    if not assets:
        raise ValueError("这个商品还没有可用图片")
    refs = [_library_image_ref(asset, team=team, label="目标商品" if index == 0 else f"目标商品{index + 1}") for index, asset in enumerate(assets)]
    return product.title, refs, "library"


def _character_library_refs(team, model_id: uuid.UUID) -> tuple[str, list, str]:
    model = (
        Model.objects.filter(Q(team=team) | Q(is_official=True), id=model_id, is_deleted=False, purged_at__isnull=True)
        .select_related("portrait_asset", "triview_asset")
        .first()
    )
    if model is None:
        raise ValueError("角色不存在或已被删除")
    assets = []
    seen = set()
    for asset in (model.portrait_asset, model.triview_asset):
        if asset is None or asset.id in seen or asset.is_deleted:
            continue
        seen.add(asset.id)
        assets.append(asset)
        if len(assets) >= MAX_IMAGES:
            break
    if not assets:
        raise ValueError("这个角色还没有可用图片")
    labels = ["目标角色", "目标角色三视图"]
    refs = [_library_image_ref(asset, team=team, label=labels[index] if index < len(labels) else f"目标角色{index + 1}") for index, asset in enumerate(assets)]
    return model.name, refs, "library"


def _temporary_image_refs(team, image_ids: list, *, noun: str) -> tuple[str, list, str]:
    refs = []
    for index, asset_id in enumerate(image_ids):
        asset = _team_asset(team, asset_id, kind=Asset.Type.IMAGE, label=f"{noun}参考图")
        label = "目标商品" if noun == "商品" else "目标角色"
        if index > 0:
            label = f"{label}{index + 1}"
        refs.append(_owned_ref(asset, kind="image", role="reference_image", label=label))
    fallback = "临时商品素材" if noun == "商品" else "临时角色素材"
    name = Asset.objects.filter(id=image_ids[0]).values_list("name", flat=True).first() or fallback
    subject = name.rsplit(".", 1)[0] if name else fallback
    if len(refs) > 1:
        subject = f"{subject}（{len(refs)}张参考图）"
    return subject, refs, "temporary"