from rest_framework import serializers

from apps.assets.serializers import AssetFileSerializer

from .models import (
    BaseAssetGroup,
    BgmTrack,
    ExportJob,
    Project,
    ProjectStage,
    ScriptSegment,
    ScriptVersion,
    StoryboardFrame,
    StoryboardVersion,
    SubtitleTrack,
    Timeline,
    TimelineClip,
    VideoSegment,
    VideoSegmentVersion,
)


def _asset_preview_url(asset) -> str:
    """资产主文件的可播放/可显示 URL(主图优先,其次首张),内嵌进各阶段序列化,
    让前端缩略图不再依赖(分页 20 条的)团队 assets 列表解析——团队资产 >20 时新生成的图本会丢。"""
    if asset is None:
        return ""
    files = list(asset.files.all())
    primary = next((f for f in files if f.is_primary), files[0] if files else None)
    return AssetFileSerializer().get_preview_url(primary) if primary else ""


class ProjectStageSerializer(serializers.ModelSerializer):
    class Meta:
        model = ProjectStage
        fields = ["id", "stage", "status", "started_at", "completed_at", "error_message", "metadata"]
        read_only_fields = fields


class VideoSegmentSerializer(serializers.ModelSerializer):
    adopted_asset = serializers.SerializerMethodField()
    adopted_asset_url = serializers.SerializerMethodField()

    class Meta:
        model = VideoSegment
        fields = ["id", "sort_order", "target_duration_seconds", "status", "error_message", "adopted_version", "adopted_asset", "adopted_asset_url"]
        read_only_fields = ["id", "sort_order", "target_duration_seconds", "status", "error_message", "adopted_version"]

    def get_adopted_asset(self, obj):
        # pipeline stage4 缩略图:暴露已采用版本对应的资产 id(供前端在 assets 里解析 preview_url)
        version = obj.adopted_version
        return str(version.asset_id) if version and version.asset_id else None

    def get_adopted_asset_url(self, obj) -> str:
        version = obj.adopted_version
        return _asset_preview_url(version.asset) if version is not None else ""


class BaseAssetGroupSerializer(serializers.ModelSerializer):
    candidate_assets = serializers.PrimaryKeyRelatedField(many=True, read_only=True)
    adopted_asset_url = serializers.SerializerMethodField()
    candidate_asset_urls = serializers.SerializerMethodField()

    class Meta:
        model = BaseAssetGroup
        fields = ["id", "kind", "prompt", "adopted_asset", "adopted_asset_url", "candidate_assets", "candidate_asset_urls", "version", "metadata", "created_at"]
        read_only_fields = fields

    def get_adopted_asset_url(self, obj) -> str:
        return _asset_preview_url(obj.adopted_asset)

    def get_candidate_asset_urls(self, obj) -> dict:
        return {str(asset.id): _asset_preview_url(asset) for asset in obj.candidate_assets.all()}


class StoryboardFrameSerializer(serializers.ModelSerializer):
    asset_url = serializers.SerializerMethodField()

    class Meta:
        model = StoryboardFrame
        fields = ["id", "script_segment", "asset", "asset_url", "sort_order", "prompt"]
        read_only_fields = fields

    def get_asset_url(self, obj) -> str:
        return _asset_preview_url(obj.asset)


class StoryboardVersionSerializer(serializers.ModelSerializer):
    frames = StoryboardFrameSerializer(many=True, read_only=True)

    class Meta:
        model = StoryboardVersion
        fields = ["id", "prompt", "is_adopted", "frames", "created_at", "updated_at"]
        read_only_fields = fields


class VideoSegmentVersionSerializer(serializers.ModelSerializer):
    class Meta:
        model = VideoSegmentVersion
        fields = ["id", "video_segment", "asset", "prompt", "is_adopted", "metadata", "created_at"]
        read_only_fields = fields


class TimelineClipSerializer(serializers.ModelSerializer):
    # 直接内嵌片段资产的可播放 URL + 是否视频,前端播放器无需再依赖(分页的)团队 assets 列表解析
    asset_url = serializers.SerializerMethodField()
    asset_is_video = serializers.SerializerMethodField()

    class Meta:
        model = TimelineClip
        fields = ["id", "asset", "asset_url", "asset_is_video", "sort_order", "start_ms", "duration_ms", "trim_start_ms", "trim_end_ms"]
        read_only_fields = ["id", "asset_url", "asset_is_video"]

    def _primary_file(self, obj):
        asset = obj.asset
        if asset is None:
            return None
        files = list(asset.files.all())
        return next((f for f in files if f.is_primary), files[0] if files else None)

    def get_asset_url(self, obj) -> str:
        f = self._primary_file(obj)
        return AssetFileSerializer().get_preview_url(f) if f else ""

    def get_asset_is_video(self, obj) -> bool:
        asset = obj.asset
        if asset is None:
            return False
        if asset.asset_type == "video":
            return True
        f = self._primary_file(obj)
        return bool(f and "video/" in (f.content_type or ""))


class TimelineExportJobSerializer(serializers.ModelSerializer):
    class Meta:
        model = ExportJob
        fields = ["id", "status", "output_asset", "progress", "error_message", "created_at", "updated_at"]
        read_only_fields = fields


class SubtitleTrackSerializer(serializers.ModelSerializer):
    class Meta:
        model = SubtitleTrack
        fields = ["id", "content", "style", "enabled"]
        read_only_fields = fields


class BgmTrackSerializer(serializers.ModelSerializer):
    asset_url = serializers.SerializerMethodField()
    asset_name = serializers.SerializerMethodField()

    class Meta:
        model = BgmTrack
        fields = ["id", "asset", "asset_url", "asset_name", "volume", "start_ms"]
        read_only_fields = fields

    def get_asset_url(self, obj) -> str:
        return _asset_preview_url(obj.asset)

    def get_asset_name(self, obj) -> str:
        return obj.asset.name if obj.asset_id else ""


class TimelineSerializer(serializers.ModelSerializer):
    clips = TimelineClipSerializer(many=True, read_only=True)
    export_jobs = TimelineExportJobSerializer(many=True, read_only=True)
    subtitle_tracks = SubtitleTrackSerializer(many=True, read_only=True)
    bgm_tracks = BgmTrackSerializer(many=True, read_only=True)

    class Meta:
        model = Timeline
        fields = ["id", "name", "aspect_ratio", "resolution", "duration_seconds", "metadata", "clips", "export_jobs", "subtitle_tracks", "bgm_tracks"]
        read_only_fields = ["id", "clips", "export_jobs", "subtitle_tracks", "bgm_tracks"]


class ExportJobSerializer(serializers.ModelSerializer):
    class Meta:
        model = ExportJob
        fields = ["id", "status", "output_asset", "progress", "error_message", "metadata", "created_at", "updated_at"]
        read_only_fields = fields


class ScriptSegmentSerializer(serializers.ModelSerializer):
    class Meta:
        model = ScriptSegment
        fields = ["id", "sort_order", "duration_seconds", "narration", "visual_prompt", "product_points"]
        read_only_fields = fields


class ScriptVersionSerializer(serializers.ModelSerializer):
    segments = ScriptSegmentSerializer(many=True, read_only=True)

    class Meta:
        model = ScriptVersion
        fields = ["id", "title", "content", "source", "is_adopted", "segments", "created_at", "updated_at"]
        read_only_fields = fields


class ProjectSerializer(serializers.ModelSerializer):
    stages = ProjectStageSerializer(many=True, read_only=True)
    video_segments = VideoSegmentSerializer(many=True, read_only=True)
    script_versions = ScriptVersionSerializer(many=True, read_only=True)
    base_asset_groups = BaseAssetGroupSerializer(many=True, read_only=True)
    storyboard_versions = StoryboardVersionSerializer(many=True, read_only=True)
    timeline = TimelineSerializer(read_only=True)

    class Meta:
        model = Project
        fields = [
            "id",
            "name",
            "product",
            "status",
            "current_stage",
            "budget_limit",
            "failure_reason",
            "metadata",
            "stages",
            "script_versions",
            "base_asset_groups",
            "storyboard_versions",
            "video_segments",
            "timeline",
            "created_at",
            "updated_at",
        ]
        read_only_fields = ["id", "status", "current_stage", "failure_reason", "created_at", "updated_at"]