medical_training/apps/case/mobile.py

"""移动端病例列表（首页 / 病例页 5 个入口）。

均读 `case_base`，只取**已发布**病例（publish_status=2 & status=1 & is_deleted=0）：

- 5.1 推荐病例（个性化）   GET /api/case/mobile/recommended/
- 5.2 科室专项           GET /api/case/mobile/specialty/
- 5.3 薄弱环节           GET /api/case/mobile/weak/
- 5.4 教学互动           GET /api/case/mobile/teaching/
- 5.5 教师任务           GET /api/case/mobile/teacher-task/（CMS 暂无指派，先同教学互动）

个性化/薄弱口径读只读表 training_record（user_id=当前用户、status='completed'），
分数按 score_type 归一百分制后比较，与《个人中心》一致。
"""
from django.db.models import Q
from rest_framework import serializers
from rest_framework.decorators import api_view, permission_classes
from rest_framework.permissions import IsAuthenticated
from rest_framework.pagination import PageNumberPagination
from rest_framework.response import Response
from drf_spectacular.utils import extend_schema

from apps.training.models import TrainingRecord
from .models import CaseBase

# 薄弱阈值：归一百分制下，最好成绩低于该分数视为「薄弱病例」
WEAK_SCORE_THRESHOLD = 70


class MobilePagination(PageNumberPagination):
    page_size = 20
    page_size_query_param = 'page_size'
    max_page_size = 100


class MobileCaseSerializer(serializers.ModelSerializer):
    """移动端病例列表元素（统一字段）。"""
    case_type_display = serializers.CharField(source='get_case_type_display', read_only=True)
    department_name = serializers.CharField(source='department.name', read_only=True)
    # 仅「薄弱环节」会注入；其余接口为 None
    my_best_score = serializers.SerializerMethodField()
    my_train_count = serializers.SerializerMethodField()

    class Meta:
        model = CaseBase
        fields = [
            'id', 'title', 'case_type', 'case_type_display', 'difficulty',
            'difficulty_score', 'department', 'department_name',
            'chief_complaint', 'description', 'patient_age', 'patient_gender',
            'tags', 'competency_tags', 'estimated_minutes', 'osce_enabled',
            'created_at', 'my_best_score', 'my_train_count',
        ]

    def _stat(self, obj):
        return (self.context.get('case_stats') or {}).get(obj.id)

    def get_my_best_score(self, obj):
        s = self._stat(obj)
        return s['best_score'] if s else None

    def get_my_train_count(self, obj):
        s = self._stat(obj)
        return s['train_count'] if s else None


# ── 公共工具 ──────────────────────────────────────────────────────────────

def _published():
    """已发布病例基集（已过滤 is_deleted）。"""
    return CaseBase.objects.filter(publish_status=2, status=1)


def _apply_common_filters(qs, request, *, allow_department=True):
    """通用查询参数：search / case_type / difficulty / department。"""
    p = request.query_params
    search = (p.get('search') or '').strip()
    if search:
        qs = qs.filter(
            Q(title__icontains=search)
            | Q(chief_complaint__icontains=search)
            | Q(tags__icontains=search)
        )
    if p.get('case_type'):
        qs = qs.filter(case_type=p['case_type'])
    if p.get('difficulty'):
        qs = qs.filter(difficulty=p['difficulty'])
    if allow_department and p.get('department'):
        qs = qs.filter(department_id=p['department'])
    return qs


def _completed_records(user):
    """当前用户已完成训练记录（只读表，不 JOIN，仅取 case_id/分数）。"""
    return TrainingRecord.objects.filter(user_id=user.id, status='completed')


def _norm_score(score, score_type):
    if score is None:
        return None
    return float(score) * 20 if score_type == 'five_point' else float(score)


def _user_case_stats(user):
    """{case_id: {best_score, train_count}}（归一百分制）。"""
    stats = {}
    rows = _completed_records(user).values('case_id', 'total_score', 'score_type')
    for r in rows:
        cid = r['case_id']
        if cid is None:
            continue
        s = _norm_score(r['total_score'], r['score_type'])
        cur = stats.setdefault(cid, {'best_score': None, 'train_count': 0})
        cur['train_count'] += 1
        if s is not None and (cur['best_score'] is None or s > cur['best_score']):
            cur['best_score'] = round(s, 1)
    return stats


def _paginate(qs, request, *, case_stats=None):
    paginator = MobilePagination()
    page = paginator.paginate_queryset(qs, request)
    ctx = {'request': request, 'case_stats': case_stats or {}}
    data = MobileCaseSerializer(page, many=True, context=ctx).data
    return paginator.get_paginated_response(data)


# ── 5.1 推荐病例（个性化）────────────────────────────────────────────────────

def _recommend_score(case, *, dept_id, trained_ids, weak_dims):
    """个性化推荐分：未训练 > 同科室 > 命中薄弱能力标签。"""
    score = 0
    if case.id not in trained_ids:
        score += 2
    if dept_id and case.department_id == dept_id:
        score += 1
    if weak_dims and case.competency_tags:
        tags = ' '.join(str(t) for t in case.competency_tags)
        if any(w and w in tags for w in weak_dims):
            score += 1
    return score


@extend_schema(summary='推荐病例（个性化）', tags=['病例列表'])
@api_view(['GET'])
@permission_classes([IsAuthenticated])
def recommended(request):
    user = request.user
    qs = _apply_common_filters(_published(), request)
    cases = list(qs.select_related('department'))

    trained_ids = set(
        _completed_records(user).values_list('case_id', flat=True)
    )
    weak_dims = [str(w) for w in (user.weak_dimensions or [])]
    dept_id = user.department_id

    cases.sort(
        key=lambda c: (
            _recommend_score(c, dept_id=dept_id, trained_ids=trained_ids, weak_dims=weak_dims),
            c.created_at or c.id,
        ),
        reverse=True,
    )
    return _paginate(cases, request)


# ── 5.2 科室专项 ────────────────────────────────────────────────────────────

@extend_schema(summary='科室专项病例', tags=['病例列表'])
@api_view(['GET'])
@permission_classes([IsAuthenticated])
def specialty(request):
    qs = _apply_common_filters(_published(), request, allow_department=False)
    dept = request.query_params.get('department') or request.user.department_id
    if dept:
        qs = qs.filter(department_id=dept)
    qs = qs.select_related('department').order_by('-created_at', '-id')
    return _paginate(qs, request)


# ── 5.3 薄弱环节 ────────────────────────────────────────────────────────────

@extend_schema(summary='薄弱环节病例', tags=['病例列表'])
@api_view(['GET'])
@permission_classes([IsAuthenticated])
def weak(request):
    user = request.user
    stats = _user_case_stats(user)
    weak_ids = [cid for cid, s in stats.items()
                if s['best_score'] is not None and s['best_score'] < WEAK_SCORE_THRESHOLD]

    base = _apply_common_filters(_published(), request).select_related('department')
    if weak_ids:
        cases = list(base.filter(id__in=weak_ids))
        # worst-first：最好成绩越低越靠前
        cases.sort(key=lambda c: stats[c.id]['best_score'])
        return _paginate(cases, request, case_stats=stats)

    # 冷启动：无低分记录 → 回退到命中用户薄弱能力标签的已发布病例（competency_tags 为 JSON，按 Python 匹配）
    weak_dims = [str(w) for w in (user.weak_dimensions or []) if w]
    cases = []
    if weak_dims:
        for c in base.order_by('-created_at', '-id'):
            tags = ' '.join(str(t) for t in (c.competency_tags or []))
            if any(w in tags for w in weak_dims):
                cases.append(c)
    return _paginate(cases, request, case_stats=stats)


# ── 5.4 教学互动 ────────────────────────────────────────────────────────────

@extend_schema(summary='教学互动病例', tags=['病例列表'])
@api_view(['GET'])
@permission_classes([IsAuthenticated])
def teaching(request):
    qs = _apply_common_filters(
        _published().filter(case_type='teaching'), request
    ).select_related('department').order_by('-created_at', '-id')
    return _paginate(qs, request)


# ── 5.5 教师任务（暂同教学互动）──────────────────────────────────────────────

@extend_schema(
    summary='教师任务病例', tags=['病例列表'],
    description='CMS 暂无「指派病例」功能，先与教学互动一致（已发布 case_type=teaching）。',
)
@api_view(['GET'])
@permission_classes([IsAuthenticated])
def teacher_task(request):
    qs = _apply_common_filters(
        _published().filter(case_type='teaching'), request
    ).select_related('department').order_by('-created_at', '-id')
    return _paginate(qs, request)