"""
出题与批题系统 API 蓝图

提供 REST API 接口：
- 出题：生成题目（异步任务，返回 task_id）
- 批题：批阅答案（异步任务，返回 task_id）

职责边界：
- RAG 服务负责：生成题目 + 批阅答案
- 后端服务负责：审核入库 + 状态管理

使用方式：
    from exam_pkg.api import exam_bp
    app.register_blueprint(exam_bp, url_prefix='/exam')

异步任务流程：
    1. POST /exam/generate → 返回 {"task_id": "xxx", ...}
    2. GET /tasks/xxx → 轮询状态，直到 completed
    3. result 字段包含完整出题/批阅结果
"""

from flask import Blueprint, request, jsonify
import os

# 导入考试管理模块
from exam_pkg.manager import (
    generate_questions_from_file,
    grade_answers,
)

# 导入网关认证模块
from auth.gateway import (
    require_gateway_auth, require_role, check_collection_permission, get_current_user
)

# 导入统一响应格式
from core.status_codes import EXAM_SUCCESS, GRADE_SUCCESS, EXAM_ERROR, GRADE_ERROR, BAD_REQUEST, UNAUTHORIZED, FORBIDDEN, NO_CONTENT, LLM_ERROR
from api.response_utils import success_response, error_response

# 合法题型
VALID_QUESTION_TYPES = {'single_choice', 'multiple_choice', 'true_false', 'fill_blank', 'subjective'}


def validate_question_types(question_types: dict) -> str:
    """
    校验 question_types 参数

    Returns:
        None 表示校验通过，字符串表示错误信息
    """
    if not isinstance(question_types, dict):
        return "question_types 必须为对象"

    for q_type, count in question_types.items():
        if q_type not in VALID_QUESTION_TYPES:
            return f"不支持的题型: {q_type}，合法值: {', '.join(sorted(VALID_QUESTION_TYPES))}"
        if not isinstance(count, int) or count < 0:
            return f"题型 {q_type} 的数量必须为非负整数，当前值: {count}"

    return None


def validate_difficulty(difficulty) -> str:
    """校验 difficulty 参数"""
    if not isinstance(difficulty, int) or difficulty < 1 or difficulty > 5:
        return "difficulty 必须为 1-5 的整数"
    return None


MAX_EXCLUDE_STEMS = 100

def validate_exclude_stems(exclude_stems) -> str:
    """校验 exclude_stems 参数（可选）"""
    if exclude_stems is None:
        return None
    if not isinstance(exclude_stems, list):
        return "exclude_stems 必须为字符串数组"
    if len(exclude_stems) > MAX_EXCLUDE_STEMS:
        return f"exclude_stems 数量不能超过 {MAX_EXCLUDE_STEMS}，当前 {len(exclude_stems)}"
    for i, stem in enumerate(exclude_stems):
        if not isinstance(stem, str) or not stem.strip():
            return f"exclude_stems 第 {i+1} 项必须为非空字符串"
    return None

# 创建蓝图
exam_bp = Blueprint('exam', __name__)


# ==================== 出题 API ====================

@exam_bp.route('/generate', methods=['POST'])
@require_gateway_auth
def api_generate_questions():
    """
    🔥 新版出题接口

    请求体:
    {
        "request_id": "uuid-optional",  // 幂等性支持
        "file_path": "public/产品手册.pdf",
        "collection": "public_kb",
        "question_types": {
            "single_choice": 3,
            "multiple_choice": 2,
            "true_false": 2,
            "fill_blank": 2,
            "subjective": 1
        },
        "difficulty": 3,
        "exclude_stems": ["已有题目的题干1", "已有题目的题干2"],  // 可选，排除已有题目避免重复
        "options": {
            "include_explanation": true,
            "max_source_chunks": 50
        }
    }

    返回:
    {
        "success": true,
        "request_id": "uuid",
        "questions": [
            {
                "question_type": "single_choice",
                "difficulty": 3,
                "content": {"stem": "...", "data": {...}, "answer": "...", "explanation": "..."},
                "source_trace": {"document_name": "...", "chunk_ids": [...], "sources": [...]}
            }
        ],
        "total": 10,
        "requested_types": {"single_choice": 3, "fill_blank": 2},
        "actual_types": {"single_choice": 3, "fill_blank": 2},
        "warnings": ["fill_blank: 请求 3 道，实际生成 2 道"],
        "source_chunks_used": 15
    }
    """
    try:
        data = request.json

        file_path = data.get('file_path')
        collection = data.get('collection')
        question_types = data.get('question_types', {})

        if not file_path or not collection:
            return error_response("MISSING_PARAMS", BAD_REQUEST, "缺少 file_path 或 collection 参数", http_status=400)

        if not question_types:
            return error_response("MISSING_PARAMS", BAD_REQUEST, "缺少 question_types 参数", http_status=400)

        # 校验题型和数量
        type_error = validate_question_types(question_types)
        if type_error:
            return error_response("INVALID_PARAMS", BAD_REQUEST, type_error, http_status=400)

        # 校验难度
        difficulty = data.get('difficulty', 3)
        diff_error = validate_difficulty(difficulty)
        if diff_error:
            return error_response("INVALID_PARAMS", BAD_REQUEST, diff_error, http_status=400)

        # 校验总题数上限
        MAX_TOTAL_QUESTIONS = 20
        total_requested = sum(question_types.values())
        if total_requested > MAX_TOTAL_QUESTIONS:
            return error_response("INVALID_PARAMS", BAD_REQUEST,
                f"总题数不能超过 {MAX_TOTAL_QUESTIONS} 道，当前请求 {total_requested} 道",
                http_status=400)

        # 校验排除题干列表（可选）
        exclude_stems = data.get('exclude_stems')
        stems_error = validate_exclude_stems(exclude_stems)
        if stems_error:
            return error_response("INVALID_PARAMS", BAD_REQUEST, stems_error, http_status=400)

        # 获取当前用户
        user = get_current_user()
        if not user:
            return error_response("UNAUTHORIZED", UNAUTHORIZED, "未认证", http_status=401)

        # 检查向量库访问权限
        if not check_collection_permission(
            role=user['role'],
            department=user.get('department', ''),
            collection_name=collection,
            operation="read"
        ):
            return error_response("FORBIDDEN", FORBIDDEN, "权限不足", http_status=403)

        # 调用新版出题接口（异步任务）
        from core.task_registry import get_registry
        import logging as _logging
        _logger = _logging.getLogger(__name__)

        registry = get_registry()
        total_questions = sum(question_types.values())
        task = registry.create_task(
            'exam_generate',
            f"出题: {os.path.basename(file_path)} ({total_questions}题)",
            total=total_questions
        )

        def _do_generate(task, fp, coll, q_types, diff, opts, req_id, excl):
            """后台执行出题"""
            registry.update_progress(task.id, stage='检索知识', message='正在检索相关文档切片...')
            result = generate_questions_from_file(
                file_path=fp,
                collection=coll,
                question_types=q_types,
                difficulty=diff,
                options=opts,
                request_id=req_id,
                exclude_stems=excl
            )
            registry.update_progress(task.id, stage='完成', message=f"生成 {result.get('total', 0)} 道题")
            return result

        registry.start_task(
            task.id, _do_generate,
            file_path, collection, question_types,
            data.get('difficulty', 3), data.get('options', {}),
            data.get('request_id'), data.get('exclude_stems')
        )

        return success_response(
            data={
                'task_id': task.id,
                'message': f'出题任务已启动 ({total_questions}题)，通过 GET /tasks/{task.id} 查询结果'
            },
            status_code=EXAM_SUCCESS,
            message="出题任务已启动"
        )

    except Exception as e:
        return error_response("EXAM_ERROR", EXAM_ERROR, str(e), http_status=500)


@exam_bp.route('/generate-smart', methods=['POST'])
@require_gateway_auth
def api_generate_smart():
    """
    AI 智能出题 - 自动分析文件并决定题型和数量

    与 /exam/generate 的区别：不需要传 question_types，AI 自动分析文档后决定

    请求体:
    {
        "file_path": "public/产品手册.pdf",
        "collection": "public_kb",
        "difficulty": 3,           // 可选，默认 3
        "max_total": 20,           // 可选，AI出题总数上限。不传则不限制
        "options": {}              // 可选
    }

    返回:
    与 /exam/generate 相同格式，额外包含 ai_analysis 字段
    """
    try:
        data = request.json

        file_path = data.get('file_path')
        collection = data.get('collection')

        if not file_path or not collection:
            return error_response("MISSING_PARAMS", BAD_REQUEST, "缺少 file_path 或 collection 参数", http_status=400)

        # 校验难度
        difficulty = data.get('difficulty', 3)
        diff_error = validate_difficulty(difficulty)
        if diff_error:
            return error_response("INVALID_PARAMS", BAD_REQUEST, diff_error, http_status=400)

        # 可选：AI出题总数上限（不传则不限制）
        max_total = data.get('max_total')
        if max_total is not None:
            try:
                max_total = int(max_total)
                if max_total <= 0:
                    return error_response("INVALID_PARAMS", BAD_REQUEST, "max_total 必须为正整数", http_status=400)
            except (ValueError, TypeError):
                return error_response("INVALID_PARAMS", BAD_REQUEST, "max_total 必须为整数", http_status=400)

        # 校验排除题干列表（可选）
        exclude_stems = data.get('exclude_stems')
        stems_error = validate_exclude_stems(exclude_stems)
        if stems_error:
            return error_response("INVALID_PARAMS", BAD_REQUEST, stems_error, http_status=400)

        # 获取当前用户
        user = get_current_user()
        if not user:
            return error_response("UNAUTHORIZED", UNAUTHORIZED, "未认证", http_status=401)

        # 检查向量库访问权限
        if not check_collection_permission(
            role=user['role'],
            department=user.get('department', ''),
            collection_name=collection,
            operation="read"
        ):
            return error_response("FORBIDDEN", FORBIDDEN, "权限不足", http_status=403)

        # AI 智能出题（异步任务）
        from core.task_registry import get_registry
        import logging as _logging
        _logger = _logging.getLogger(__name__)

        registry = get_registry()
        task = registry.create_task(
            'exam_generate',
            f"AI智能出题: {os.path.basename(file_path)}"
        )

        def _do_smart_generate(task, fp, coll, diff, opts, req_id, excl, max_t):
            """后台执行 AI 智能出题"""
            registry.update_progress(task.id, stage='AI分析', message='正在分析文档内容...')
            from exam_pkg.manager import analyze_file_for_exam
            ai_analysis = analyze_file_for_exam(file_path=fp, collection=coll, max_total=max_t)

            q_types = ai_analysis.get('question_types', {})
            if not q_types or sum(q_types.values()) == 0:
                raise ValueError("AI 分析后未生成有效题型配置")

            total = sum(q_types.values())
            registry.update_progress(task.id, total=total, stage='生成题目',
                                     message=f"AI 推荐 {total} 道题，正在生成...")

            result = generate_questions_from_file(
                file_path=fp, collection=coll,
                question_types=q_types, difficulty=diff,
                options=opts, request_id=req_id, exclude_stems=excl
            )
            result['ai_analysis'] = ai_analysis
            registry.update_progress(task.id, stage='完成', message=f"生成 {result.get('total', 0)} 道题")
            return result

        registry.start_task(
            task.id, _do_smart_generate,
            file_path, collection,
            data.get('difficulty', 3), data.get('options', {}),
            data.get('request_id'), data.get('exclude_stems'),
            max_total
        )

        return success_response(
            data={
                'task_id': task.id,
                'message': 'AI 智能出题任务已启动，通过 GET /tasks/' + task.id + ' 查询结果'
            },
            status_code=EXAM_SUCCESS,
            message="AI 智能出题任务已启动"
        )

    except Exception as e:
        return error_response("EXAM_ERROR", EXAM_ERROR, str(e), http_status=500)


# ==================== 批题 API ====================

@exam_bp.route('/grade', methods=['POST'])
@require_gateway_auth
def api_grade_answers():
    """
    🔥 新版批题接口

    请求体:
    {
        "request_id": "uuid-optional",
        "answers": [
            {
                "question_id": "uuid",
                "question_type": "single_choice",
                "content": {"answer": "B"},
                "student_answer": "A",
                "max_score": 2
            },
            {
                "question_id": "uuid",
                "question_type": "fill_blank",
                "content": {"answer": [["答案1", "同义词"], ["答案2"]]},
                "student_answer": ["学生答案1", "学生答案2"],
                "max_score": 4
            },
            {
                "question_id": "uuid",
                "question_type": "subjective",
                "content": {
                    "stem": "简述...",
                    "data": {"scoring_points": [...]},
                    "answer": "参考范文..."
                },
                "student_answer": "学生作答内容...",
                "max_score": 10
            }
        ]
    }

    说明：
    - content 字段与出题接口返回的 content 结构一致，后端可直接透传
    - 客观题：content 只需包含 answer
    - 填空题：content.answer 格式为 [["答案1", "同义词"], ...] 每空一个列表
    - 主观题：content 需包含 stem + answer + data.scoring_points

    返回:
    {
        "success": true,
        "request_id": "uuid",
        "results": [
            {
                "question_id": "uuid",
                "score": 2,
                "max_score": 2,
                "grading_status": "success",
                "details": {"correct": true, "student_answer": "A", "correct_answer": "B", "feedback": "..."}
            }
        ],
        "total_score": 10.5,
        "total_max_score": 16.0,
        "score_rate": 65.6
    }

    grading_status 取值：
    - "success": 评分成功
    - "failed": 评分失败（LLM 超时/解析失败等），score 为 0
    """
    try:
        data = request.json

        answers = data.get('answers', [])
        if not answers:
            return error_response("MISSING_PARAMS", BAD_REQUEST, "缺少答案数据", http_status=400)
        if not isinstance(answers, list):
            return error_response("INVALID_PARAMS", BAD_REQUEST, "answers 必须为数组", http_status=400)

        # 校验每道题的 question_type
        for i, ans in enumerate(answers):
            q_type = ans.get('question_type')
            if q_type not in VALID_QUESTION_TYPES:
                return error_response("INVALID_PARAMS", BAD_REQUEST,
                    f"第 {i+1} 题的 question_type 无效: {q_type}，合法值: {', '.join(sorted(VALID_QUESTION_TYPES))}",
                    http_status=400)

        # 调用批题接口（异步任务）
        from core.task_registry import get_registry
        registry = get_registry()

        task = registry.create_task(
            'exam_grade',
            f"批阅: {len(answers)} 道题",
            total=len(answers)
        )

        def _do_grade(task, ans_list, req_id):
            """后台执行批阅"""
            registry.update_progress(task.id, stage='批阅中', message='正在逐题评分...')
            result = grade_answers(answers=ans_list, request_id=req_id)
            registry.update_progress(task.id, stage='完成',
                                     message=f"批阅完成，得分率 {result.get('score_rate', 0):.1f}%")
            return result

        registry.start_task(task.id, _do_grade, answers, data.get('request_id'))

        return success_response(
            data={
                'task_id': task.id,
                'message': f'批阅任务已启动 ({len(answers)}题)，通过 GET /tasks/{task.id} 查询结果'
            },
            status_code=GRADE_SUCCESS,
            message="批阅任务已启动"
        )

    except Exception as e:
        return error_response("GRADE_ERROR", GRADE_ERROR, str(e), http_status=500)


# ==================== 健康检查 ====================

@exam_bp.route('/health', methods=['GET'])
def api_health():
    """健康检查"""
    return jsonify({
        "status": "ok",
        "service": "exam-api",
        "version": "2.0"
    })