"""
整理失败的用户反馈、阶段识别和恢复动作投影。
"""

from collections import Counter
from dataclasses import dataclass
from enum import StrEnum
from typing import Optional


class TransferFailureStage(StrEnum):
    """
    整理失败所在的可操作阶段。
    """

    # 无法访问或读取源文件
    SOURCE_ACCESS = "source_access"
    # 无法确定正确的媒体身份
    RECOGNITION = "recognition"
    # 无法构造可执行整理计划
    PLANNING = "planning"
    # 目标存储、权限或空间不可用
    DESTINATION_ACCESS = "destination_access"
    # 文件转移执行失败
    TRANSFER = "transfer"
    # 覆盖现有目标的策略或操作失败
    OVERWRITE = "overwrite"
    # 媒体已入库，但下载器清理未完成
    DOWNLOADER_CLEANUP = "downloader_cleanup"
    # 租约、执行状态或检查点冲突
    EXECUTION = "execution"
    # 尚不能归入已知业务阶段的失败
    UNKNOWN = "unknown"


@dataclass(frozen=True, slots=True)
class TransferFailureFeedback:
    """
    整理失败的公开阶段、动作和自动处理状态。

    :param stage: 本次失败所在的可操作业务阶段
    :param action: 推荐用户执行的修复操作说明
    :param retryable: 是否仍允许自动或用户发起重试，默认 True
    :param auto_paused: 是否因失败策略暂停自动恢复
    """

    stage: TransferFailureStage
    action: str
    retryable: bool = True
    auto_paused: bool = False


_STAGE_RULES: tuple[tuple[TransferFailureStage, tuple[str, ...]], ...] = (
    (
        TransferFailureStage.SOURCE_ACCESS,
        ("源文件不存在", "无法访问源文件", "读取源文件", "文件不存在", "没有找到源文件"),
    ),
    (
        TransferFailureStage.RECOGNITION,
        (
            "未识别到媒体",
            "识别媒体",
            "媒体信息",
            "无法识别",
            "识别失败",
            "没有找到可整理",
        ),
    ),
    (
        TransferFailureStage.PLANNING,
        ("整理计划", "规划失败", "计划失败", "缺少整理", "规划输入"),
    ),
    (
        TransferFailureStage.OVERWRITE,
        ("覆盖策略", "目标已存在", "跳过覆盖", "不覆盖"),
    ),
    (
        TransferFailureStage.DOWNLOADER_CLEANUP,
        ("删除种子", "清理下载器", "下载器清理", "移除种子"),
    ),
    (
        TransferFailureStage.EXECUTION,
        ("租约", "正在被其他", "执行快照", "任务状态", "人工复核"),
    ),
    (
        TransferFailureStage.DESTINATION_ACCESS,
        (
            "目标目录",
            "目标文件",
            "目标存储",
            "写入目标",
            "写入失败",
            "不可写",
            "创建目录",
            "剩余空间",
            "没有权限",
            "权限不足",
        ),
    ),
)

_STAGE_ACTIONS: dict[TransferFailureStage, str] = {
    TransferFailureStage.SOURCE_ACCESS: "检查源文件是否存在，以及 MoviePilot 的读取权限和路径映射",
    TransferFailureStage.RECOGNITION: "修改文件名，或指定正确的媒体来源和媒体 ID 后重新整理",
    TransferFailureStage.PLANNING: "检查媒体身份、目标目录和整理参数后点击“重新生成计划”",
    TransferFailureStage.DESTINATION_ACCESS: "检查目标存储连接、目录权限和剩余空间，修复后重试",
    TransferFailureStage.TRANSFER: "检查源文件和目标存储，修复后重新整理",
    TransferFailureStage.OVERWRITE: "调整覆盖策略，或移除目标位置的旧文件后重新整理",
    TransferFailureStage.DOWNLOADER_CLEANUP: "媒体已入库；请检查下载器任务并手动清理未完成的下载器操作",
    TransferFailureStage.EXECUTION: "刷新整理历史，等待任务结束；仍无法继续时提交人工复核",
    TransferFailureStage.UNKNOWN: "检查源文件、路径映射和目标存储，修复后重新整理",
}

_STAGE_LABELS: dict[TransferFailureStage, str] = {
    TransferFailureStage.SOURCE_ACCESS: "源文件访问",
    TransferFailureStage.RECOGNITION: "媒体识别",
    TransferFailureStage.PLANNING: "整理计划",
    TransferFailureStage.DESTINATION_ACCESS: "目标存储访问",
    TransferFailureStage.TRANSFER: "文件转移",
    TransferFailureStage.OVERWRITE: "覆盖策略",
    TransferFailureStage.DOWNLOADER_CLEANUP: "下载器清理",
    TransferFailureStage.EXECUTION: "任务执行",
    TransferFailureStage.UNKNOWN: "未知阶段",
}


def transfer_failure_stage_label(stage: Optional[str | TransferFailureStage]) -> str:
    """
    把稳定失败阶段编码转换为后端通知使用的中文标签。
    """
    try:
        normalized = TransferFailureStage(stage or TransferFailureStage.UNKNOWN)
    except ValueError:
        return str(stage or _STAGE_LABELS[TransferFailureStage.UNKNOWN])
    return _STAGE_LABELS[normalized]


def classify_transfer_failure(
        error: Optional[object],
        *,
        overwrite_skipped: bool = False,
        auto_paused: bool = False,
) -> TransferFailureFeedback:
    """
    根据稳定业务关键词生成用户可执行的失败阶段和恢复动作。
    """
    if overwrite_skipped:
        stage = TransferFailureStage.OVERWRITE
    else:
        message = " ".join(str(error or "").split())
        stage = TransferFailureStage.TRANSFER
        for candidate, markers in _STAGE_RULES:
            if any(marker in message for marker in markers):
                stage = candidate
                break
    return TransferFailureFeedback(
        stage=stage,
        action=_STAGE_ACTIONS[stage],
        retryable=stage not in {
            TransferFailureStage.OVERWRITE,
            TransferFailureStage.DOWNLOADER_CLEANUP,
        },
        auto_paused=auto_paused,
    )


def format_transfer_failure_message(
        error: Optional[object],
        *,
        stage: Optional[str] = None,
        action: Optional[str] = None,
        source_path: Optional[str] = None,
        target_path: Optional[str] = None,
        retry_count: Optional[int] = None,
        max_retries: Optional[int] = None,
        auto_paused: bool = False,
) -> str:
    """
    把整理失败转换为包含原因、阶段和下一步动作的公开文案。
    """
    feedback = classify_transfer_failure(error, auto_paused=auto_paused)
    lines = [
        f"失败阶段：{transfer_failure_stage_label(stage or feedback.stage)}",
        f"原因：{' '.join(str(error or '整理失败').split())}",
        f"下一步：{action or feedback.action}",
    ]
    if source_path:
        lines.insert(0, f"源文件：{source_path}")
    if target_path:
        lines.insert(1 if source_path else 0, f"目标路径：{target_path}")
    if retry_count is not None and max_retries is not None:
        lines.append(f"重试状态：已尝试 {retry_count}/{max_retries} 次")
    if auto_paused:
        lines.append("当前状态：自动整理已暂停，请修复原因后点击“重新整理”，或删除失败记录后重新扫描")
    return "\n".join(lines)


@dataclass(frozen=True, slots=True)
class TransferFailureNotification:
    """
    整理失败聚合器保存的单条通知快照。

    :param media_title: 通知中展示的媒体标题
    :param season_episode: 通知中展示的季集范围
    :param reason: 整理失败的具体可读原因
    :param history_id: 关联整理历史的数据库主键
    :param image: 通知展示图片地址；未取得时为 None
    :param username: 触发整理的本地用户名；未绑定时为 None
    :param manual_identity: 媒体身份是否由用户手动指定
    :param task_id: 持久整理任务的稳定标识
    :param source_path: 失败任务的源路径；未记录时为 None
    :param target_path: 计划目标路径；规划前失败时可为 None
    :param failure_stage: 失败所在的业务阶段
    :param recovery_action: 允许执行或推荐执行的恢复动作
    :param retry_count: 当前恢复周期已经消耗的重试次数
    :param max_retries: 当前策略允许的最大重试次数；不适用时为 None
    :param auto_paused: 是否因失败策略暂停自动恢复
    :param cleanup_status: 媒体入库后下载器清理的状态
    :param cleanup_error: 下载器清理失败原因；无错误时为 None
    """

    media_title: str
    season_episode: str
    reason: str
    history_id: Optional[int]
    image: Optional[str]
    username: Optional[str]
    manual_identity: bool = False
    task_id: Optional[str] = None
    source_path: Optional[str] = None
    target_path: Optional[str] = None
    failure_stage: Optional[str] = None
    recovery_action: Optional[str] = None
    retry_count: Optional[int] = None
    max_retries: Optional[int] = None
    auto_paused: bool = False
    cleanup_status: Optional[str] = None
    cleanup_error: Optional[str] = None


def render_transfer_failure_notification(
    notifications: list[TransferFailureNotification],
) -> tuple[str, str]:
    """
    把非空失败分组投影为标题和正文，按钮及消息派发仍由整理链处理。
    """
    first = notifications[0]
    history_ids = [item.history_id for item in notifications if item.history_id]
    if len(notifications) == 1:
        history_hint = (
            (
                "如果按钮不可用，可回复：\n"
                f"```\n/redo {history_ids[0]}\n"
                f"/redo {history_ids[0]} [media_source]|[media_id]|[类型]\n```\n"
                "自动重试或手动识别整理。"
                if first.manual_identity
                else f"如果按钮不可用，可回复：\n```\n/redo {history_ids[0]}\n```"
            )
            if history_ids
            else ""
        )
        context_lines = [
            f"失败阶段：{transfer_failure_stage_label(first.failure_stage)}",
            f"源文件：{first.source_path}" if first.source_path else None,
            f"目标路径：{first.target_path}" if first.target_path else None,
            f"原因：{first.reason}",
            f"下一步：{first.recovery_action}" if first.recovery_action else None,
            (
                f"重试状态：已尝试 {first.retry_count}/{first.max_retries} 次"
                if first.retry_count is not None and first.max_retries is not None
                else None
            ),
            (
                "当前状态：自动整理已暂停，请修复原因后点击“重新整理”，"
                "或删除失败记录后重新扫描"
                if first.auto_paused
                else None
            ),
            history_hint,
        ]
        text = "\n".join(line for line in context_lines if line).strip()
        title = (
            f"{first.media_title} 未识别到媒体信息，无法入库！"
            if first.manual_identity
            else f"{first.media_title} {first.season_episode} 入库失败！"
        )
    else:
        reason_counts = Counter(item.reason for item in notifications)
        reason_lines = [
            f"- {reason} × {count}"
            for reason, count in reason_counts.most_common()
        ]
        history_text = "、".join(f"#{history_id}" for history_id in history_ids)
        text_parts = [
            f"失败文件：{len(notifications)} 个",
            "原因统计：",
            *reason_lines,
        ]
        source_paths = [item.source_path for item in notifications if item.source_path]
        if source_paths:
            text_parts.append("源文件：" + "、".join(source_paths[:3]))
        if any(item.auto_paused for item in notifications):
            text_parts.append("部分文件已达到自动重试上限，自动整理已暂停，请在整理历史中处理。")
        if history_text:
            text_parts.extend([f"整理记录：{history_text}", "可在整理历史中批量处理。"])
        text = "\n".join(text_parts)
        title = f"{first.media_title} 入库失败（{len(notifications)} 个文件）"
    return title, text


def cleanup_update_fields(
    cleanup_status: str, cleanup_error: Optional[str] = None,
) -> dict[str, Optional[str]]:
    """
    投影清理状态的业务字段，数据库层只暂存最终标量更新。
    """
    values = {
        "cleanup_status": cleanup_status,
        "cleanup_error": cleanup_error,
    }
    if cleanup_status == "failed":
        # 清理失败发生在媒体入库成功之后，单独覆盖阶段字段，避免历史页把
        # 空 errmsg 解释成普通文件转移失败。
        feedback = classify_transfer_failure("下载器清理失败")
        values.update(
            failure_stage=feedback.stage.value,
            recovery_action=feedback.action,
        )
    elif cleanup_status == "resolved":
        # 用户已在下载器中人工完成清理时，同时关闭专属于清理步骤的失败提示；
        # 媒体整理成功状态及其余历史字段保持不变。
        values.update(
            failure_stage=None,
            recovery_action=None,
            cleanup_error=None,
        )
    return values