import asyncio
import json
import logging
import os
from datetime import datetime, timezone
from urllib.parse import urlparse

from sqlalchemy import or_, select

from app.config import settings
from app.enums.generation_status import GenerationRecordPipelineStage
from app.models.base import async_session
from app.models.generation_record import GenerationRecord
from app.services.generation.refund_service import mark_generation_record_failed_and_refund_once
from app.services.image_gen import download_image, get_active_image_engine
from app.services.media_token_usage_snapshot_service import sync_generation_record_media_token_snapshot
from app.services.provider_limit import provider_limit
from app.services.resource_accounting_service import (
    record_generation_record_generated_resource,
    safe_file_size,
)
from app.services.video_cover_service import create_video_cover_for_local_video
from app.services.video_gen import _log_video_response, download_video, get_active_engine, poll_task_status
from app.services.video_upscale.media_service import build_part_mp4_path, probe_video, safe_remove

logger = logging.getLogger("videogen")

POLL_INTERVAL = 30
MAX_POLLS = 60

_PROVIDER_RECOVERABLE_STAGES = {
    None,
    "",
    GenerationRecordPipelineStage.CREATING_PROVIDER_TASK.value,
    GenerationRecordPipelineStage.WAITING_REMOTE.value,
    GenerationRecordPipelineStage.POLLING.value,
    GenerationRecordPipelineStage.RESULT_READY.value,
    GenerationRecordPipelineStage.DOWNLOADING.value,
}


def _is_provider_stage(record: GenerationRecord) -> bool:
    return (record.pipeline_stage or "") in _PROVIDER_RECOVERABLE_STAGES


def _source_date_dir(record: GenerationRecord) -> str:
    created = record.created_at
    if created is None:
        created = datetime.now(timezone.utc)
    return created.strftime("%Y/%m/%d")


def _normalize_image_extension(output_format: str | None, remote_url: str | None = None) -> str:
    value = str(output_format or "").strip().lower()
    if value in {"jpg", "jpeg"}:
        return "jpg"
    if value == "png":
        return "png"
    if value == "webp":
        return "webp"

    if remote_url:
        try:
            path = urlparse(remote_url).path or ""
        except Exception:
            path = str(remote_url)
        suffix = os.path.splitext(path)[1].lower().lstrip(".")
        if suffix in {"jpg", "jpeg"}:
            return "jpg"
        if suffix == "png":
            return "png"
        if suffix == "webp":
            return "webp"

    return "jpg"


async def _download_generation_record_upscale_source(
    record: GenerationRecord,
    remote_url: str,
) -> tuple[str, int]:
    date_dir = _source_date_dir(record)
    dest_dir = os.path.join(settings.STORAGE_LOCAL_PATH, "_upscale_source", date_dir)
    os.makedirs(dest_dir, exist_ok=True)
    final_path = os.path.join(dest_dir, f"{record.id}.source.mp4")
    if os.path.isfile(final_path) and os.path.getsize(final_path) > 0:
        await probe_video(final_path)
        return final_path, safe_file_size(final_path)

    part_path = build_part_mp4_path(final_path)
    try:
        async with provider_limit("result_download", settings.RESULT_DOWNLOAD_MAX_CONCURRENCY):
            await download_video(remote_url, part_path)
        if not os.path.isfile(part_path) or os.path.getsize(part_path) <= 0:
            raise RuntimeError("超分源视频下载完成但临时文件为空")
        await probe_video(part_path)
        os.replace(part_path, final_path)
        return final_path, safe_file_size(final_path)
    except Exception:
        safe_remove(part_path)
        raise


async def handle_generation_record_video_succeeded(
    db,
    record: GenerationRecord,
    *,
    remote_url: str,
    provider_response: dict | None,
    video_tokens: int = 0,
) -> bool:
    """处理 GenerationRecord 原视频生成成功。

    返回 True 表示已进入超分队列；False 表示按原流程直接完成。
    """
    record.video_tokens_used = int(video_tokens or 0)
    await sync_generation_record_media_token_snapshot(db, record, provider_response=provider_response or {})

    if bool(record.video_upscale_enabled_snapshot) and record.video_upscale_snapshot_json:
        record.pipeline_stage = GenerationRecordPipelineStage.DOWNLOADING.value
        await db.flush()
        source_path, source_size = await _download_generation_record_upscale_source(record, remote_url)
        from app.services.video_upscale.task_service import enqueue_upscale_task, prepare_video_upscale_task

        upscale = await prepare_video_upscale_task(
            db,
            generation_record=record,
            source_local_path=source_path,
            source_file_size_bytes=source_size,
            source_remote_url=remote_url,
        )
        # enqueue_upscale_task 会先提交数据库，再投递 Celery；投递失败由 gen_recovery 补投。
        await enqueue_upscale_task(db, upscale=upscale, reason="generation_record_source_ready")
        logger.info("GenerationRecord 已进入视频超分队列: record_id=%s upscale_task_id=%s", record.id, upscale.id)
        return True

    storage_path = None
    file_size_bytes = 0
    if settings.STORAGE_TYPE == "local" and remote_url:
        try:
            date_dir = _source_date_dir(record)
            dest_dir = os.path.join(settings.STORAGE_LOCAL_PATH, date_dir)
            os.makedirs(dest_dir, exist_ok=True)
            dest = os.path.join(dest_dir, f"{record.id}.mp4")
            await download_video(remote_url, dest)
            record.video_url = f"/generate/videos/{date_dir}/{record.id}.mp4"
            cover_url, _cover_storage_path = create_video_cover_for_local_video(
                record_id=record.id,
                video_path=dest,
                date_dir=date_dir,
                log_prefix=f"GenerationRecord视频封面生成 record_id={record.id}",
            )
            record.video_cover_url = cover_url
            storage_path = dest
            file_size_bytes = safe_file_size(dest)
        except Exception as exc:
            logger.warning("GenerationRecord 最终视频本地保存失败，回退远程地址: record_id=%s error=%s", record.id, exc)
            record.video_url = remote_url
    else:
        record.video_url = remote_url

    record.status = "completed"
    record.pipeline_stage = GenerationRecordPipelineStage.DONE.value
    record.generated_at = datetime.now(timezone.utc)
    record.error_message = None
    if record.video_url:
        await record_generation_record_generated_resource(
            db,
            record,
            resource_url=record.video_url,
            storage_path=storage_path,
            file_size_bytes=file_size_bytes,
            remote_url=remote_url,
            generated_at=record.generated_at,
        )
    await db.commit()
    return False


class TaskQueue:
    def __init__(self):
        self.queue: asyncio.Queue[str] = asyncio.Queue()
        self.running = False
        self._active: dict[str, int] = {}

    async def enqueue(self, record_id: str):
        await self.queue.put(record_id)

    async def recover(self):
        async with async_session() as db:
            result = await db.execute(
                select(GenerationRecord).where(
                    GenerationRecord.status == "generating",
                    GenerationRecord.seedance_task_id.isnot(None),
                    GenerationRecord.deleted_at.is_(None),
                    or_(
                        GenerationRecord.pipeline_stage.is_(None),
                        GenerationRecord.pipeline_stage.in_(
                            [stage for stage in _PROVIDER_RECOVERABLE_STAGES if stage]
                        ),
                    ),
                )
            )
            records = result.scalars().all()
            for record in records:
                await self.queue.put(record.id)
                logger.info("Recovered task: %s (seedance: %s stage=%s)", record.id, record.seedance_task_id, record.pipeline_stage)

    async def run(self):
        self.running = True
        logger.info("Video queue started")
        while self.running:
            try:
                record_id = await asyncio.wait_for(self.queue.get(), timeout=5.0)
            except asyncio.TimeoutError:
                continue
            try:
                await self._process(record_id)
            except Exception as exc:
                logger.exception("Error processing %s: %s", record_id, exc)
            finally:
                self.queue.task_done()
        logger.info("Video queue stopped")

    async def _process(self, record_id: str):
        async with async_session() as db:
            result = await db.execute(
                select(GenerationRecord).where(
                    GenerationRecord.id == record_id,
                    GenerationRecord.deleted_at.is_(None),
                ).with_for_update().limit(1)
            )
            record = result.scalar_one_or_none()
            if not record or record.status != "generating":
                return
            if record.gen_type == "video":
                if not _is_provider_stage(record):
                    return
                await self._process_video(db, record)
            else:
                await self._process_image(db, record)

    async def _process_video(self, db, record: GenerationRecord):
        record_id = record.id
        if not record.seedance_task_id:
            record.pipeline_stage = GenerationRecordPipelineStage.FAILED.value
            await mark_generation_record_failed_and_refund_once(db, record=record, error_message="缺少外部任务ID")
            await db.commit()
            return

        record.pipeline_stage = GenerationRecordPipelineStage.POLLING.value
        try:
            engine = await get_active_engine(db)
            poll_result = await poll_task_status(engine, record.seedance_task_id)
        except Exception as exc:
            logger.error("Poll error for %s: %s", record_id, exc)
            count = self._active.get(record_id, 0) + 1
            self._active[record_id] = count
            if count >= MAX_POLLS:
                record.pipeline_stage = GenerationRecordPipelineStage.FAILED.value
                await mark_generation_record_failed_and_refund_once(db, record=record, error_message=f"轮询超时: {exc}")
                await db.commit()
                self._active.pop(record_id, None)
            else:
                await db.commit()
                await asyncio.sleep(POLL_INTERVAL)
                await self.queue.put(record_id)
            return

        status = poll_result["status"]
        try:
            resp_data = json.loads(poll_result.get("response_data", "{}"))
        except (json.JSONDecodeError, TypeError):
            resp_data = {}
        _log_video_response(record_id, resp_data, poll_result.get("error"))

        if status == "succeeded":
            file_url = str(poll_result.get("video_url") or "").strip()
            if not file_url:
                record.pipeline_stage = GenerationRecordPipelineStage.FAILED.value
                await mark_generation_record_failed_and_refund_once(db, record=record, error_message="供应商成功但未返回视频地址")
                await db.commit()
                return
            record.pipeline_stage = GenerationRecordPipelineStage.RESULT_READY.value
            await db.flush()
            try:
                await handle_generation_record_video_succeeded(
                    db,
                    record,
                    remote_url=file_url,
                    provider_response=resp_data,
                    video_tokens=poll_result.get("video_tokens", 0),
                )
            except Exception as exc:
                await db.rollback()
                result = await db.execute(
                    select(GenerationRecord).where(GenerationRecord.id == record_id).with_for_update().limit(1)
                )
                failed_record = result.scalar_one_or_none()
                if failed_record:
                    failed_record.pipeline_stage = GenerationRecordPipelineStage.FAILED.value
                    await mark_generation_record_failed_and_refund_once(
                        db,
                        record=failed_record,
                        error_message=f"视频结果下载失败: {exc}",
                    )
                    await db.commit()
                logger.exception("GenerationRecord 视频成功结果处理失败: %s", record_id)
            self._active.pop(record_id, None)
            return

        if status == "failed":
            record.pipeline_stage = GenerationRecordPipelineStage.FAILED.value
            await mark_generation_record_failed_and_refund_once(
                db,
                record=record,
                error_message=poll_result.get("error", "视频生成失败"),
            )
            self._active.pop(record_id, None)
            await db.commit()
            logger.info("Video task failed: %s", record_id)
            return

        count = self._active.get(record_id, 0) + 1
        self._active[record_id] = count
        if count >= MAX_POLLS:
            record.pipeline_stage = GenerationRecordPipelineStage.FAILED.value
            await mark_generation_record_failed_and_refund_once(db, record=record, error_message="视频生成超时")
            self._active.pop(record_id, None)
            await db.commit()
            logger.info("Video task timed out: %s", record_id)
        else:
            await db.commit()
            await asyncio.sleep(POLL_INTERVAL)
            await self.queue.put(record_id)

    async def _process_image(self, db, record: GenerationRecord):
        """Process image generation task - calls API directly."""
        record_id = record.id
        from app.services.image_gen import submit_image_task

        try:
            engine = await get_active_image_engine(db)
            poll_result = await asyncio.to_thread(
                submit_image_task,
                db,
                engine,
                record,
                include_media_references=False,
            )

            if not isinstance(poll_result, dict):
                raise RuntimeError("图片供应商返回结构异常")

            items = poll_result.get("items") or []
            if not isinstance(items, list):
                raise RuntimeError("图片供应商返回结果列表异常")
            if not items:
                raise RuntimeError("图片供应商未返回图片结果")
            if len(items) != 1:
                raise RuntimeError(f"图片供应商单图返回数量异常，期望 1，实际 {len(items)}")

            item = items[0] or {}
            if not isinstance(item, dict):
                raise RuntimeError("图片供应商返回单项结果结构异常")

            item_error = item.get("error_message") or item.get("error_code")
            if item_error:
                raise RuntimeError(str(item_error))

            remote_url = str(item.get("remote_result_url") or "").strip()
            if not remote_url:
                raise RuntimeError("图片供应商成功响应但没有图片地址")

            storage_path = None
            file_size_bytes = 0
            if settings.STORAGE_TYPE == "local":
                try:
                    date_dir = _source_date_dir(record)
                    dest_dir = os.path.join(settings.STORAGE_IMAGE_LOCAL_PATH, date_dir)
                    os.makedirs(dest_dir, exist_ok=True)
                    extension = _normalize_image_extension(item.get("output_format"), remote_url)
                    dest = os.path.join(dest_dir, f"{record_id}.{extension}")
                    await download_image(remote_url, dest)
                    record.image_url = f"/generate/images/{date_dir}/{record_id}.{extension}"
                    storage_path = dest
                    file_size_bytes = safe_file_size(dest)
                except Exception as exc:
                    logger.warning("GenerationRecord 图片本地保存失败，回退远程地址: record_id=%s error=%s", record_id, exc)
                    record.image_url = remote_url
            else:
                record.image_url = remote_url

            record.image_tokens_used = int(poll_result.get("image_tokens", 0) or 0)
            provider_response = poll_result.get("response_data") or {}
            await sync_generation_record_media_token_snapshot(
                db,
                record,
                provider_response=provider_response if isinstance(provider_response, dict) else {},
            )
            record.status = "completed"
            record.pipeline_stage = GenerationRecordPipelineStage.DONE.value
            record.generated_at = datetime.now(timezone.utc)
            record.error_message = None
            if record.image_url:
                await record_generation_record_generated_resource(
                    db,
                    record,
                    resource_url=record.image_url,
                    storage_path=storage_path,
                    file_size_bytes=file_size_bytes,
                    remote_url=remote_url,
                    generated_at=record.generated_at,
                )
            await db.commit()
            logger.info("Image task completed: %s", record_id)

        except Exception as exc:
            record.pipeline_stage = GenerationRecordPipelineStage.FAILED.value
            await mark_generation_record_failed_and_refund_once(
                db,
                record=record,
                error_message=(getattr(exc, "safe_message", None) or str(exc) or "图片生成失败"),
            )
            await db.commit()
            logger.error("Image task failed: %s, error: %s", record_id, exc, exc_info=True)

    def stop(self):
        """Signal the queue to stop."""
        self.running = False


task_queue = TaskQueue()