use super::*;
use crate::openai_image_generation::{
    OpenAiReferenceImage, create_openai_image_edit_with_references,
};

#[derive(Clone, Copy, Debug, Eq, PartialEq)]
pub(crate) enum PuzzleImageModel {
    GptImage2,
    Gemini31FlashPreview,
}

impl PuzzleImageModel {
    pub(crate) fn provider_name(self) -> &'static str {
        VECTOR_ENGINE_PROVIDER
    }

    pub(crate) fn request_model_name(self) -> &'static str {
        GPT_IMAGE_2_MODEL
    }

    pub(crate) fn candidate_source_type(self) -> &'static str {
        match self {
            Self::GptImage2 => "generated:gpt-image-2",
            Self::Gemini31FlashPreview => "generated:nanobanana2",
        }
    }
}

pub(crate) struct PuzzleVectorEngineSettings {
    pub(crate) base_url: String,
    pub(crate) api_key: String,
    pub(crate) request_timeout_ms: u64,
    pub(crate) external_api_audit_state: Option<AppState>,
    pub(crate) external_api_audit_user_id: Option<String>,
    pub(crate) external_api_audit_profile_id: Option<String>,
    pub(crate) external_api_audit_request_id: Option<String>,
}

pub(crate) struct PuzzleGeneratedImages {
    pub(crate) task_id: String,
    pub(crate) images: Vec<PuzzleDownloadedImage>,
}

pub(crate) struct PuzzleResolvedReferenceImage {
    pub(crate) mime_type: String,
    pub(crate) bytes_len: usize,
    pub(crate) bytes: Vec<u8>,
}

pub(crate) struct GeneratedPuzzleImageCandidate {
    pub(crate) record: PuzzleGeneratedImageCandidateRecord,
    pub(crate) downloaded_image: PuzzleDownloadedImage,
}

impl GeneratedPuzzleImageCandidate {
    pub(crate) fn into_record(self) -> PuzzleGeneratedImageCandidateRecord {
        self.record
    }
}

pub(crate) trait GeneratedPuzzleImageCandidatesExt {
    fn into_records(self) -> Vec<PuzzleGeneratedImageCandidateRecord>;
}

impl GeneratedPuzzleImageCandidatesExt for Vec<GeneratedPuzzleImageCandidate> {
    fn into_records(self) -> Vec<PuzzleGeneratedImageCandidateRecord> {
        self.into_iter()
            .map(GeneratedPuzzleImageCandidate::into_record)
            .collect()
    }
}

#[derive(Clone)]
pub(crate) struct PuzzleDownloadedImage {
    pub(crate) extension: String,
    pub(crate) mime_type: String,
    pub(crate) bytes: Vec<u8>,
}

impl PuzzleDownloadedImage {
    pub(crate) fn from_resolved_reference_image(image: PuzzleResolvedReferenceImage) -> Self {
        Self {
            extension: puzzle_mime_to_extension(image.mime_type.as_str()).to_string(),
            mime_type: normalize_puzzle_downloaded_image_mime_type(image.mime_type.as_str()),
            bytes: image.bytes,
        }
    }

    pub(crate) fn from_openai_image(image: DownloadedOpenAiImage) -> Self {
        Self {
            extension: image.extension,
            mime_type: normalize_puzzle_downloaded_image_mime_type(image.mime_type.as_str()),
            bytes: image.bytes,
        }
    }
}

impl PuzzleVectorEngineSettings {
    fn to_openai_settings(&self) -> crate::openai_image_generation::OpenAiImageSettings {
        crate::openai_image_generation::OpenAiImageSettings {
            base_url: self.base_url.clone(),
            api_key: self.api_key.clone(),
            request_timeout_ms: self.request_timeout_ms,
            external_api_audit_state: self.external_api_audit_state.clone(),
            external_api_audit_user_id: self.external_api_audit_user_id.clone(),
            external_api_audit_profile_id: self.external_api_audit_profile_id.clone(),
            external_api_audit_request_id: self.external_api_audit_request_id.clone(),
        }
    }

    pub(crate) fn with_external_api_audit_context(
        mut self,
        request_context: &RequestContext,
        user_id: Option<String>,
        profile_id: Option<String>,
    ) -> Self {
        self.external_api_audit_user_id = user_id;
        self.external_api_audit_profile_id = profile_id;
        self.external_api_audit_request_id = Some(request_context.request_id().to_string());
        self
    }
}

pub(crate) struct ParsedPuzzleImageDataUrl {
    pub(crate) mime_type: String,
    pub(crate) bytes: Vec<u8>,
}

pub(crate) struct GeneratedPuzzleAssetResponse {
    pub(crate) image_src: String,
    pub(crate) asset_id: String,
}

pub(crate) struct GeneratedPuzzleUiBackgroundResponse {
    pub(crate) image_src: String,
    pub(crate) object_key: String,
}

#[derive(Clone, Debug)]
pub(crate) struct GeneratedPuzzleLevelAssetResponse {
    pub(crate) image_src: String,
    pub(crate) object_key: String,
}

#[derive(Clone, Debug)]
pub(crate) struct GeneratedPuzzleLevelAssetBundle {
    pub(crate) level_scene: GeneratedPuzzleLevelAssetResponse,
    pub(crate) ui_spritesheet: GeneratedPuzzleLevelAssetResponse,
    pub(crate) level_background: GeneratedPuzzleLevelAssetResponse,
}

pub(crate) fn resolve_puzzle_image_model(value: Option<&str>) -> PuzzleImageModel {
    match value.map(str::trim).filter(|value| !value.is_empty()) {
        Some(PUZZLE_IMAGE_MODEL_GEMINI_31_FLASH_PREVIEW) => {
            tracing::warn!(
                requested_model = PUZZLE_IMAGE_MODEL_GEMINI_31_FLASH_PREVIEW,
                effective_model = GPT_IMAGE_2_MODEL,
                "拼图 nanobanana2 历史选项已回落到 VectorEngine GPT-image-2"
            );
            PuzzleImageModel::Gemini31FlashPreview
        }
        _ => PuzzleImageModel::GptImage2,
    }
}

pub(crate) fn require_puzzle_vector_engine_settings(
    state: &PuzzleApiState,
) -> Result<PuzzleVectorEngineSettings, AppError> {
    let base_url = state.vector_engine_base_url().trim().trim_end_matches('/');
    if base_url.is_empty() {
        return Err(
            AppError::from_status(StatusCode::SERVICE_UNAVAILABLE).with_details(json!({
                "provider": VECTOR_ENGINE_PROVIDER,
                "message": "VectorEngine 图片生成地址未配置",
                "reason": "VECTOR_ENGINE_BASE_URL 未配置",
            })),
        );
    }

    let api_key = state
        .vector_engine_api_key()
        .map(str::trim)
        .filter(|value| !value.is_empty())
        .ok_or_else(|| {
            AppError::from_status(StatusCode::SERVICE_UNAVAILABLE).with_details(json!({
                "provider": VECTOR_ENGINE_PROVIDER,
                "message": "VectorEngine 图片生成密钥未配置",
                "reason": "VECTOR_ENGINE_API_KEY 未配置",
            }))
        })?;

    Ok(PuzzleVectorEngineSettings {
        base_url: base_url.to_string(),
        api_key: api_key.to_string(),
        request_timeout_ms: state.vector_engine_image_request_timeout_ms().max(1),
        external_api_audit_state: Some(state.root_state().clone()),
        external_api_audit_user_id: None,
        external_api_audit_profile_id: None,
        external_api_audit_request_id: None,
    })
}

pub(crate) fn build_puzzle_image_http_client(
    state: &PuzzleApiState,
    _image_model: PuzzleImageModel,
) -> Result<reqwest::Client, AppError> {
    let settings = require_puzzle_vector_engine_settings(state)?;

    build_openai_image_http_client(&settings.to_openai_settings())
}

pub(crate) fn to_puzzle_generated_image_candidate(
    candidate: &PuzzleGeneratedImageCandidateRecord,
) -> PuzzleGeneratedImageCandidate {
    // SpacetimeDB 模块反序列化的是 module-puzzle 的持久化结构，必须保留 snake_case 字段名；HTTP 响应层再单独映射为 camelCase。
    PuzzleGeneratedImageCandidate {
        candidate_id: candidate.candidate_id.clone(),
        image_src: candidate.image_src.clone(),
        asset_id: candidate.asset_id.clone(),
        prompt: candidate.prompt.clone(),
        actual_prompt: candidate.actual_prompt.clone(),
        source_type: candidate.source_type.clone(),
        selected: candidate.selected,
    }
}

pub(crate) async fn create_puzzle_vector_engine_image_generation(
    http_client: &reqwest::Client,
    settings: &PuzzleVectorEngineSettings,
    image_model: PuzzleImageModel,
    prompt: &str,
    negative_prompt: &str,
    size: &str,
    candidate_count: u32,
    reference_image: Option<&PuzzleResolvedReferenceImage>,
) -> Result<PuzzleGeneratedImages, AppError> {
    if let Some(reference_image) = reference_image {
        return create_puzzle_vector_engine_image_edit(
            http_client,
            settings,
            image_model,
            prompt,
            negative_prompt,
            size,
            candidate_count,
            reference_image,
        )
        .await;
    }

    let generated = create_openai_image_generation(
        http_client,
        &settings.to_openai_settings(),
        prompt,
        Some(negative_prompt),
        size,
        candidate_count,
        &[],
        "拼图 VectorEngine 图片生成失败",
    )
    .await?;

    Ok(PuzzleGeneratedImages {
        task_id: generated.task_id,
        images: generated
            .images
            .into_iter()
            .map(PuzzleDownloadedImage::from_openai_image)
            .collect(),
    })
}

pub(crate) async fn create_puzzle_vector_engine_image_edit(
    http_client: &reqwest::Client,
    settings: &PuzzleVectorEngineSettings,
    _image_model: PuzzleImageModel,
    prompt: &str,
    negative_prompt: &str,
    size: &str,
    candidate_count: u32,
    reference_image: &PuzzleResolvedReferenceImage,
) -> Result<PuzzleGeneratedImages, AppError> {
    let file_name = format!(
        "puzzle-reference.{}",
        puzzle_mime_to_extension(reference_image.mime_type.as_str())
    );
    let generated = create_openai_image_edit_with_references(
        http_client,
        &settings.to_openai_settings(),
        prompt,
        Some(negative_prompt),
        size,
        candidate_count,
        &[OpenAiReferenceImage {
            bytes: reference_image.bytes.clone(),
            mime_type: reference_image.mime_type.clone(),
            file_name,
        }],
        "拼图 VectorEngine 图片编辑失败",
    )
    .await?;

    Ok(PuzzleGeneratedImages {
        task_id: generated.task_id,
        images: generated
            .images
            .into_iter()
            .map(PuzzleDownloadedImage::from_openai_image)
            .collect(),
    })
}

pub(crate) fn build_puzzle_downloaded_image_reference(
    image: &PuzzleDownloadedImage,
) -> PuzzleResolvedReferenceImage {
    PuzzleResolvedReferenceImage {
        mime_type: image.mime_type.clone(),
        bytes_len: image.bytes.len(),
        bytes: image.bytes.clone(),
    }
}

#[cfg(test)]
pub(crate) fn build_puzzle_vector_engine_image_request_body(
    image_model: PuzzleImageModel,
    prompt: &str,
    negative_prompt: &str,
    size: &str,
    candidate_count: u32,
    reference_image: Option<&PuzzleResolvedReferenceImage>,
) -> Value {
    let body = serde_json::Map::from_iter([
        (
            "model".to_string(),
            Value::String(image_model.request_model_name().to_string()),
        ),
        (
            "prompt".to_string(),
            Value::String(build_puzzle_vector_engine_prompt(prompt, negative_prompt)),
        ),
        ("n".to_string(), json!(candidate_count.clamp(1, 1))),
        ("size".to_string(), Value::String(size.to_string())),
    ]);
    let _ = reference_image;

    Value::Object(body)
}

pub(crate) fn build_puzzle_vector_engine_generation_prompt(
    prompt: &str,
    has_reference_image: bool,
) -> String {
    let prompt = prompt.trim();
    if !has_reference_image {
        return prompt.to_string();
    }

    format!(
        concat!(
            "请以随请求提供的参考图作为第一优先级生成依据，严格保留参考图的主要主体、构图关系、视角、姿态、配色和光影氛围；",
            "允许按下面文字要求做风格化和细节增强，但不要改成与参考图无关的新画面。\n",
            "{prompt}"
        ),
        prompt = prompt,
    )
}

pub(crate) fn has_puzzle_reference_image(reference_image_src: Option<&str>) -> bool {
    reference_image_src
        .map(str::trim)
        .map(|value| !value.is_empty())
        .unwrap_or(false)
}

pub(crate) fn collect_puzzle_reference_image_sources(
    legacy_reference_image_src: Option<&str>,
    reference_image_srcs: &[String],
    reference_image_asset_object_id: Option<&str>,
    reference_image_asset_object_ids: &[String],
) -> Vec<String> {
    let mut sources = Vec::new();
    for source in reference_image_asset_object_id
        .into_iter()
        .chain(reference_image_asset_object_ids.iter().map(String::as_str))
        .map(|asset_object_id| {
            asset_object_id
                .trim()
                .strip_prefix("asset-object:")
                .unwrap_or_else(|| asset_object_id.trim())
        })
        .filter(|asset_object_id| !asset_object_id.is_empty())
        .map(|asset_object_id| format!("asset-object:{asset_object_id}"))
        .chain(
            legacy_reference_image_src
                .into_iter()
                .chain(reference_image_srcs.iter().map(String::as_str))
                .map(str::to_string),
        )
    {
        let normalized = source.trim();
        if normalized.is_empty() {
            continue;
        }
        if !sources
            .iter()
            .any(|existing: &String| existing == normalized)
        {
            sources.push(normalized.to_string());
        }
        if sources.len() >= PUZZLE_REFERENCE_IMAGE_SOURCE_LIMIT {
            break;
        }
    }
    sources
}

pub(crate) fn has_puzzle_reference_images(
    legacy_reference_image_src: Option<&str>,
    reference_image_srcs: &[String],
    reference_image_asset_object_id: Option<&str>,
    reference_image_asset_object_ids: &[String],
) -> bool {
    !collect_puzzle_reference_image_sources(
        legacy_reference_image_src,
        reference_image_srcs,
        reference_image_asset_object_id,
        reference_image_asset_object_ids,
    )
    .is_empty()
}

pub(crate) fn should_use_puzzle_reference_image_generation(
    reference_image_src: Option<&str>,
    use_reference_image_generation: bool,
) -> bool {
    use_reference_image_generation && has_puzzle_reference_image(reference_image_src)
}

#[cfg(test)]
pub(crate) fn build_puzzle_vector_engine_prompt(prompt: &str, negative_prompt: &str) -> String {
    let prompt = prompt.trim();
    let negative_prompt = negative_prompt.trim();
    if negative_prompt.is_empty() {
        return prompt.to_string();
    }

    format!("{prompt}\n避免：{negative_prompt}")
}

pub(crate) fn parse_puzzle_asset_object_reference(source: &str) -> Option<&str> {
    source
        .trim()
        .strip_prefix("asset-object:")
        .map(str::trim)
        .filter(|value| !value.is_empty())
}

pub(crate) async fn resolve_puzzle_reference_image(
    state: &PuzzleApiState,
    http_client: &reqwest::Client,
    source: &str,
    owner_user_id: Option<&str>,
) -> Result<PuzzleResolvedReferenceImage, AppError> {
    let trimmed = source.trim();
    if trimmed.is_empty() {
        return Err(
            AppError::from_status(StatusCode::BAD_REQUEST).with_details(json!({
                "provider": "puzzle",
                "field": "referenceImageSrc",
                "message": "参考图不能为空。",
            })),
        );
    }

    if let Some(asset_object_id) = parse_puzzle_asset_object_reference(trimmed) {
        return resolve_puzzle_reference_asset_object(
            state,
            http_client,
            asset_object_id,
            owner_user_id,
        )
        .await;
    }

    if let Some(parsed) = parse_puzzle_image_data_url(trimmed) {
        let bytes_len = parsed.bytes.len();
        if bytes_len > PUZZLE_REFERENCE_IMAGE_MAX_BYTES {
            return Err(
                AppError::from_status(StatusCode::BAD_REQUEST).with_details(json!({
                    "provider": "puzzle",
                    "field": "referenceImageSrc",
                    "message": build_puzzle_reference_image_too_large_message(bytes_len),
                    "maxBytes": PUZZLE_REFERENCE_IMAGE_MAX_BYTES,
                    "actualBytes": bytes_len,
                })),
            );
        }
        return Ok(PuzzleResolvedReferenceImage {
            mime_type: parsed.mime_type,
            bytes_len,
            bytes: parsed.bytes,
        });
    }

    if !trimmed.starts_with('/') {
        return Err(
            AppError::from_status(StatusCode::BAD_REQUEST).with_details(json!({
                "provider": "puzzle",
                "field": "referenceImageSrc",
                "message": "参考图必须是 assetObjectId、Data URL 或 /generated-* 旧路径。",
            })),
        );
    }

    let object_key = trimmed.trim_start_matches('/');
    if LegacyAssetPrefix::from_object_key(object_key).is_none() {
        return Err(
            AppError::from_status(StatusCode::BAD_REQUEST).with_details(json!({
                "provider": "puzzle",
                "field": "referenceImageSrc",
                "message": "参考图当前只支持 assetObjectId 或 /generated-* 旧路径。",
            })),
        );
    }

    let oss_client = state.oss_client().ok_or_else(|| {
        AppError::from_status(StatusCode::SERVICE_UNAVAILABLE).with_details(json!({
            "provider": "aliyun-oss",
            "reason": "OSS 未完成环境变量配置",
        }))
    })?;
    let signed = oss_client
        .sign_get_object_url(OssSignedGetObjectUrlRequest {
            object_key: object_key.to_string(),
            expire_seconds: Some(60),
        })
        .map_err(map_puzzle_asset_oss_error)?;
    let signed_read_url = signed.signed_url;
    download_signed_puzzle_reference_image(
        http_client,
        signed_read_url,
        object_key,
        None,
        "referenceImageSrc",
    )
    .await
}

pub(crate) async fn resolve_puzzle_reference_image_as_data_url(
    state: &PuzzleApiState,
    http_client: &reqwest::Client,
    source: &str,
) -> Result<PuzzleResolvedReferenceImage, AppError> {
    resolve_puzzle_reference_image(state, http_client, source, None).await
}

async fn resolve_puzzle_reference_asset_object(
    state: &PuzzleApiState,
    http_client: &reqwest::Client,
    asset_object_id: &str,
    owner_user_id: Option<&str>,
) -> Result<PuzzleResolvedReferenceImage, AppError> {
    let asset_object = state
        .spacetime_client()
        .get_asset_object(asset_object_id.to_string())
        .await
        .map_err(map_puzzle_client_error)?
        .ok_or_else(|| {
            AppError::from_status(StatusCode::BAD_REQUEST).with_details(json!({
                "provider": "asset-object",
                "field": "referenceImageAssetObjectId",
                "assetObjectId": asset_object_id,
                "message": "参考图资产不存在或当前账号不可见。",
            }))
        })?;
    let oss_client = state.oss_client().ok_or_else(|| {
        AppError::from_status(StatusCode::SERVICE_UNAVAILABLE).with_details(json!({
            "provider": "aliyun-oss",
            "reason": "OSS 未完成环境变量配置",
        }))
    })?;
    validate_puzzle_reference_asset_object(
        &asset_object,
        owner_user_id,
        oss_client.config_bucket(),
    )?;
    let signed = oss_client
        .sign_get_object_url(OssSignedGetObjectUrlRequest {
            object_key: asset_object.object_key.clone(),
            expire_seconds: Some(60),
        })
        .map_err(map_puzzle_asset_oss_error)?;
    let content_type = asset_object.content_type.clone();
    download_signed_puzzle_reference_image(
        http_client,
        signed.signed_url,
        asset_object.object_key.as_str(),
        content_type.as_deref(),
        "referenceImageAssetObjectId",
    )
    .await
}

pub(crate) fn validate_puzzle_reference_asset_object(
    asset_object: &module_assets::AssetObjectRecord,
    owner_user_id: Option<&str>,
    oss_bucket: &str,
) -> Result<(), AppError> {
    if asset_object.bucket.trim() != oss_bucket.trim() {
        return Err(
            AppError::from_status(StatusCode::BAD_REQUEST).with_details(json!({
                "provider": "asset-object",
                "field": "referenceImageAssetObjectId",
                "assetObjectId": asset_object.asset_object_id,
                "message": "参考图资产 bucket 与当前服务 OSS 配置不一致。",
            })),
        );
    }
    if asset_object.asset_kind.trim() != "puzzle_cover_image" {
        return Err(
            AppError::from_status(StatusCode::BAD_REQUEST).with_details(json!({
                "provider": "asset-object",
                "field": "referenceImageAssetObjectId",
                "assetObjectId": asset_object.asset_object_id,
                "message": "参考图资产类型不属于拼图图片。",
            })),
        );
    }
    let content_type = asset_object
        .content_type
        .as_deref()
        .map(str::trim)
        .unwrap_or_default();
    if !content_type.starts_with("image/") {
        return Err(
            AppError::from_status(StatusCode::BAD_REQUEST).with_details(json!({
                "provider": "asset-object",
                "field": "referenceImageAssetObjectId",
                "assetObjectId": asset_object.asset_object_id,
                "message": "参考图资产不是图片类型。",
            })),
        );
    }
    if asset_object.content_length == 0
        || asset_object.content_length > PUZZLE_REFERENCE_IMAGE_MAX_BYTES as u64
    {
        return Err(
            AppError::from_status(StatusCode::BAD_REQUEST).with_details(json!({
                "provider": "asset-object",
                "field": "referenceImageAssetObjectId",
                "assetObjectId": asset_object.asset_object_id,
                "message": build_puzzle_reference_image_too_large_message(
                    asset_object.content_length as usize,
                ),
                "maxBytes": PUZZLE_REFERENCE_IMAGE_MAX_BYTES,
                "actualBytes": asset_object.content_length,
            })),
        );
    }
    if let Some(expected_owner_user_id) = owner_user_id
        .map(str::trim)
        .filter(|value| !value.is_empty())
    {
        let actual_owner_user_id = asset_object
            .owner_user_id
            .as_deref()
            .map(str::trim)
            .filter(|value| !value.is_empty());
        if actual_owner_user_id != Some(expected_owner_user_id) {
            return Err(
                AppError::from_status(StatusCode::FORBIDDEN).with_details(json!({
                    "provider": "asset-object",
                    "field": "referenceImageAssetObjectId",
                    "assetObjectId": asset_object.asset_object_id,
                    "message": "参考图资产不属于当前账号。",
                })),
            );
        }
    }

    Ok(())
}

async fn download_signed_puzzle_reference_image(
    http_client: &reqwest::Client,
    signed_read_url: String,
    object_key: &str,
    fallback_content_type: Option<&str>,
    field: &str,
) -> Result<PuzzleResolvedReferenceImage, AppError> {
    let response = http_client
        .get(signed_read_url.as_str())
        .send()
        .await
        .map_err(|error| map_puzzle_image_request_error(format!("读取拼图参考图失败：{error}")))?;
    let status = response.status();
    let content_type = response
        .headers()
        .get(reqwest::header::CONTENT_TYPE)
        .and_then(|value| value.to_str().ok())
        .or(fallback_content_type)
        .unwrap_or("image/png")
        .to_string();
    let body = response.bytes().await.map_err(|error| {
        map_puzzle_image_request_error(format!("读取拼图参考图内容失败：{error}"))
    })?;
    if !status.is_success() {
        return Err(
            AppError::from_status(StatusCode::BAD_GATEWAY).with_details(json!({
                "provider": "aliyun-oss",
                "message": format!("读取参考图失败，状态码：{status}"),
                "objectKey": object_key,
                "field": field,
            })),
        );
    }
    if body.is_empty() {
        return Err(
            AppError::from_status(StatusCode::BAD_GATEWAY).with_details(json!({
                "provider": "aliyun-oss",
                "message": "读取参考图失败：对象内容为空",
                "objectKey": object_key,
                "field": field,
            })),
        );
    }

    let mime_type = normalize_puzzle_downloaded_image_mime_type(content_type.as_str());
    let bytes_len = body.len();
    Ok(PuzzleResolvedReferenceImage {
        mime_type,
        bytes_len,
        bytes: body.to_vec(),
    })
}

pub(crate) async fn persist_puzzle_generated_asset(
    state: &PuzzleApiState,
    owner_user_id: &str,
    session_id: &str,
    level_name: &str,
    candidate_id: &str,
    task_id: &str,
    image: PuzzleDownloadedImage,
    generated_at_micros: i64,
) -> Result<GeneratedPuzzleAssetResponse, AppError> {
    let oss_client = state.oss_client().ok_or_else(|| {
        AppError::from_status(StatusCode::SERVICE_UNAVAILABLE).with_details(json!({
            "provider": "aliyun-oss",
            "reason": "OSS 未完成环境变量配置",
        }))
    })?;
    let http_client = reqwest::Client::new();
    let asset_id = format!("asset-{generated_at_micros}");
    let put_result = oss_client
        .put_object(
            &http_client,
            OssPutObjectRequest {
                prefix: LegacyAssetPrefix::PuzzleAssets,
                path_segments: vec![
                    sanitize_path_segment(session_id, "session"),
                    sanitize_path_segment(level_name, "puzzle"),
                    sanitize_path_segment(candidate_id, "candidate"),
                    asset_id.clone(),
                ],
                file_name: format!("image.{}", image.extension),
                content_type: Some(image.mime_type.clone()),
                access: OssObjectAccess::Private,
                metadata: build_puzzle_asset_metadata(owner_user_id, session_id, candidate_id),
                body: image.bytes,
            },
        )
        .await
        .map_err(map_puzzle_asset_oss_error)?;
    let head = oss_client
        .head_object(
            &http_client,
            OssHeadObjectRequest {
                object_key: put_result.object_key.clone(),
            },
        )
        .await
        .map_err(map_puzzle_asset_oss_error)?;
    let asset_object = state
        .spacetime_client()
        .confirm_asset_object(
            build_asset_object_upsert_input(
                generate_asset_object_id(generated_at_micros),
                head.bucket,
                head.object_key,
                AssetObjectAccessPolicy::Private,
                head.content_type.or(Some(image.mime_type)),
                head.content_length,
                head.etag,
                "puzzle_cover_image".to_string(),
                Some(task_id.to_string()),
                Some(owner_user_id.to_string()),
                None,
                Some(session_id.to_string()),
                generated_at_micros,
            )
            .map_err(map_puzzle_asset_field_error)?,
        )
        .await;
    match asset_object {
        Ok(asset_object) => {
            if let Err(error) = state
                .spacetime_client()
                .bind_asset_object_to_entity(
                    build_asset_entity_binding_input(
                        generate_asset_binding_id(generated_at_micros),
                        asset_object.asset_object_id,
                        PUZZLE_ENTITY_KIND.to_string(),
                        session_id.to_string(),
                        candidate_id.to_string(),
                        "puzzle_cover_image".to_string(),
                        Some(owner_user_id.to_string()),
                        None,
                        generated_at_micros,
                    )
                    .map_err(map_puzzle_asset_field_error)?,
                )
                .await
            {
                handle_puzzle_asset_spacetime_index_error(
                    error,
                    owner_user_id,
                    session_id,
                    candidate_id,
                    "绑定拼图资产对象到实体",
                )?;
            }
        }
        Err(error) => handle_puzzle_asset_spacetime_index_error(
            error,
            owner_user_id,
            session_id,
            candidate_id,
            "确认拼图资产对象",
        )?,
    }

    Ok(GeneratedPuzzleAssetResponse {
        image_src: put_result.legacy_public_path,
        asset_id,
    })
}

pub(crate) async fn persist_puzzle_ui_background_image(
    state: &PuzzleApiState,
    owner_user_id: &str,
    session_id: &str,
    level_name: &str,
    task_id: &str,
    image: DownloadedOpenAiImage,
) -> Result<GeneratedPuzzleUiBackgroundResponse, AppError> {
    let oss_client = state.oss_client().ok_or_else(|| {
        AppError::from_status(StatusCode::SERVICE_UNAVAILABLE).with_details(json!({
            "provider": "aliyun-oss",
            "reason": "OSS 未完成环境变量配置",
        }))
    })?;
    let http_client = reqwest::Client::new();
    let put_result = oss_client
        .put_object(
            &http_client,
            OssPutObjectRequest {
                prefix: LegacyAssetPrefix::PuzzleAssets,
                path_segments: vec![
                    sanitize_path_segment(session_id, "session"),
                    sanitize_path_segment(level_name, "puzzle"),
                    "ui-background".to_string(),
                    sanitize_path_segment(task_id, "task"),
                ],
                file_name: format!("background.{}", image.extension),
                content_type: Some(image.mime_type.clone()),
                access: OssObjectAccess::Private,
                metadata: build_puzzle_ui_background_asset_metadata(owner_user_id, session_id),
                body: image.bytes,
            },
        )
        .await
        .map_err(map_puzzle_asset_oss_error)?;
    Ok(GeneratedPuzzleUiBackgroundResponse {
        image_src: put_result.legacy_public_path,
        object_key: put_result.object_key,
    })
}

pub(crate) async fn persist_puzzle_level_asset_image(
    state: &PuzzleApiState,
    owner_user_id: &str,
    session_id: &str,
    level_name: &str,
    task_id: &str,
    path_segment: &str,
    asset_kind: &str,
    slot: &str,
    file_stem: &str,
    image: PuzzleDownloadedImage,
) -> Result<GeneratedPuzzleLevelAssetResponse, AppError> {
    let oss_client = state.oss_client().ok_or_else(|| {
        AppError::from_status(StatusCode::SERVICE_UNAVAILABLE).with_details(json!({
            "provider": "aliyun-oss",
            "reason": "OSS 未完成环境变量配置",
        }))
    })?;
    let http_client = reqwest::Client::new();
    let put_result = oss_client
        .put_object(
            &http_client,
            OssPutObjectRequest {
                prefix: LegacyAssetPrefix::PuzzleAssets,
                path_segments: vec![
                    sanitize_path_segment(session_id, "session"),
                    sanitize_path_segment(level_name, "puzzle"),
                    sanitize_path_segment(path_segment, "level-asset"),
                    sanitize_path_segment(task_id, "task"),
                ],
                file_name: format!("{file_stem}.{}", image.extension),
                content_type: Some(image.mime_type.clone()),
                access: OssObjectAccess::Private,
                metadata: build_puzzle_level_asset_metadata(
                    owner_user_id,
                    session_id,
                    asset_kind,
                    slot,
                ),
                body: image.bytes,
            },
        )
        .await
        .map_err(map_puzzle_asset_oss_error)?;

    Ok(GeneratedPuzzleLevelAssetResponse {
        image_src: put_result.legacy_public_path,
        object_key: put_result.object_key,
    })
}

pub(crate) fn handle_puzzle_asset_spacetime_index_error(
    error: SpacetimeClientError,
    owner_user_id: &str,
    session_id: &str,
    candidate_id: &str,
    stage: &str,
) -> Result<(), AppError> {
    if should_skip_asset_operation_billing_for_connectivity(&error) {
        // 中文注释：OSS 已经持有真实图片，资产索引的 SpacetimeDB 短暂失败只影响历史检索，不应阻断本次生图展示。
        tracing::warn!(
            provider = "spacetimedb",
            owner_user_id,
            session_id,
            candidate_id,
            stage,
            error = %error,
            "拼图图片资产索引写入因 SpacetimeDB 连接不可用而降级跳过"
        );
        return Ok(());
    }

    Err(map_puzzle_asset_spacetime_error(error))
}

pub(crate) fn build_puzzle_asset_metadata(
    owner_user_id: &str,
    session_id: &str,
    candidate_id: &str,
) -> BTreeMap<String, String> {
    BTreeMap::from([
        ("asset_kind".to_string(), "puzzle_cover_image".to_string()),
        ("owner_user_id".to_string(), owner_user_id.to_string()),
        ("entity_kind".to_string(), PUZZLE_ENTITY_KIND.to_string()),
        ("entity_id".to_string(), session_id.to_string()),
        ("slot".to_string(), candidate_id.to_string()),
    ])
}

pub(crate) fn build_puzzle_ui_background_asset_metadata(
    owner_user_id: &str,
    session_id: &str,
) -> BTreeMap<String, String> {
    BTreeMap::from([
        (
            "asset_kind".to_string(),
            "puzzle_ui_background_image".to_string(),
        ),
        ("owner_user_id".to_string(), owner_user_id.to_string()),
        ("entity_kind".to_string(), PUZZLE_ENTITY_KIND.to_string()),
        ("entity_id".to_string(), session_id.to_string()),
        ("slot".to_string(), "ui_background".to_string()),
    ])
}

pub(crate) fn build_puzzle_level_asset_metadata(
    owner_user_id: &str,
    session_id: &str,
    asset_kind: &str,
    slot: &str,
) -> BTreeMap<String, String> {
    BTreeMap::from([
        ("asset_kind".to_string(), asset_kind.to_string()),
        ("owner_user_id".to_string(), owner_user_id.to_string()),
        ("entity_kind".to_string(), PUZZLE_ENTITY_KIND.to_string()),
        ("entity_id".to_string(), session_id.to_string()),
        ("slot".to_string(), slot.to_string()),
    ])
}

pub(crate) fn parse_puzzle_image_data_url(value: &str) -> Option<ParsedPuzzleImageDataUrl> {
    let body = value.strip_prefix("data:")?;
    let (mime_type, data) = body.split_once(";base64,")?;
    if !mime_type.starts_with("image/") {
        return None;
    }
    let bytes = decode_puzzle_base64(data)?;
    Some(ParsedPuzzleImageDataUrl {
        mime_type: mime_type.to_string(),
        bytes,
    })
}

pub(crate) fn decode_puzzle_base64(value: &str) -> Option<Vec<u8>> {
    let cleaned = value.trim().replace(char::is_whitespace, "");
    let mut output = Vec::with_capacity(cleaned.len() * 3 / 4);
    let mut buffer = 0u32;
    let mut bits = 0u8;

    for byte in cleaned.bytes() {
        let value = match byte {
            b'A'..=b'Z' => byte - b'A',
            b'a'..=b'z' => byte - b'a' + 26,
            b'0'..=b'9' => byte - b'0' + 52,
            b'+' => 62,
            b'/' => 63,
            b'=' => break,
            _ => return None,
        } as u32;
        buffer = (buffer << 6) | value;
        bits += 6;
        while bits >= 8 {
            bits -= 8;
            output.push(((buffer >> bits) & 0xFF) as u8);
        }
    }

    Some(output)
}

pub(crate) fn normalize_puzzle_downloaded_image_mime_type(content_type: &str) -> String {
    let mime_type = content_type
        .split(';')
        .next()
        .map(str::trim)
        .unwrap_or("image/jpeg");
    match mime_type {
        "image/png" | "image/webp" | "image/jpeg" | "image/jpg" | "image/gif" => {
            mime_type.to_string()
        }
        _ => "image/jpeg".to_string(),
    }
}

pub(crate) fn puzzle_mime_to_extension(mime_type: &str) -> &str {
    match mime_type {
        "image/png" => "png",
        "image/webp" => "webp",
        "image/gif" => "gif",
        _ => "jpg",
    }
}

pub(crate) fn map_puzzle_image_request_error(message: String) -> AppError {
    let is_timeout = is_puzzle_request_timeout_message(message.as_str());
    let status = if is_timeout {
        StatusCode::GATEWAY_TIMEOUT
    } else {
        StatusCode::BAD_GATEWAY
    };

    AppError::from_status(status).with_details(json!({
        "provider": "puzzle-image",
        "message": message,
        "timeout": is_timeout,
    }))
}

pub(crate) fn is_puzzle_request_timeout_message(message: &str) -> bool {
    let lower = message.to_ascii_lowercase();
    lower.contains("timed out")
        || lower.contains("timeout")
        || lower.contains("operation timed out")
        || lower.contains("deadline has elapsed")
}

pub(crate) fn map_puzzle_asset_oss_error(error: platform_oss::OssError) -> AppError {
    map_oss_error(error, "aliyun-oss")
}

pub(crate) fn map_puzzle_asset_spacetime_error(error: SpacetimeClientError) -> AppError {
    AppError::from_status(StatusCode::BAD_GATEWAY).with_details(json!({
        "provider": "spacetimedb",
        "message": error.to_string(),
    }))
}

pub(crate) fn map_puzzle_asset_field_error(error: AssetObjectFieldError) -> AppError {
    AppError::from_status(StatusCode::INTERNAL_SERVER_ERROR).with_details(json!({
        "provider": "asset-object",
        "message": error.to_string(),
    }))
}

pub(crate) fn sanitize_path_segment(value: &str, fallback: &str) -> String {
    let sanitized = value
        .trim()
        .chars()
        .map(|ch| {
            if ch.is_ascii_alphanumeric() || ('\u{4e00}'..='\u{9fff}').contains(&ch) {
                ch
            } else {
                '-'
            }
        })
        .collect::<String>()
        .trim_matches('-')
        .to_string();
    if sanitized.is_empty() {
        fallback.to_string()
    } else {
        sanitized
    }
}

pub(crate) fn current_utc_micros() -> i64 {
    let duration = SystemTime::now()
        .duration_since(UNIX_EPOCH)
        .unwrap_or_default();
    (duration.as_secs() as i64) * 1_000_000 + i64::from(duration.subsec_micros())
}