{
  "$schema": "http://json-schema.org/draft-07/schema#",
  "title": "Examination Question Set",
  "description": "CS 知识应试强化系统 - 题目集 JSON Schema",
  "type": "object",
  "required": ["topic", "type", "schema_version", "questions"],
  "properties": {
    "topic": {
      "type": "string",
      "description": "主题 slug"
    },
    "type": {
      "type": "string",
      "enum": ["single_choice", "multiple_choice", "true_false", "fill_blank", "short_answer", "code_reading", "scenario"],
      "description": "题目类型"
    },
    "schema_version": {
      "type": "string",
      "const": "1.0.0"
    },
    "generated": {
      "type": "string",
      "format": "date-time"
    },
    "questions": {
      "type": "array",
      "items": {
        "$ref": "#/definitions/question"
      }
    }
  },
  "definitions": {
    "question": {
      "type": "object",
      "required": ["id", "type", "difficulty", "tags", "question", "explanation"],
      "properties": {
        "id": {
          "type": "string",
          "pattern": "^(sc|mc|tf|fb|sa|cr|sn)-[0-9]{3}$",
          "description": "题目唯一标识，格式: typecode-number（如 fb-001, sc-003）"
        },
        "type": {
          "type": "string",
          "enum": ["single_choice", "multiple_choice", "true_false", "fill_blank", "short_answer", "code_reading", "scenario"]
        },
        "difficulty": {
          "type": "integer",
          "minimum": 1,
          "maximum": 5
        },
        "tags": {
          "type": "array",
          "items": { "type": "string" }
        },
        "question": {
          "type": "string"
        },
        "explanation": {
          "type": "string"
        },
        "source": {
          "type": ["string", "null"],
          "default": null
        },
        "related": {
          "type": "array",
          "items": { "type": "string" },
          "default": []
        },
        "options": {
          "description": "选项（选择题类型）或 null"
        },
        "answer": {
          "description": "答案（根据题型不同而不同）"
        },
        "answer_rule": {
          "type": "string",
          "enum": ["any", "all", "ordered"],
          "default": "any",
          "description": "填空题答案匹配规则"
        },
        "keywords": {
          "type": "array",
          "items": { "type": "string" },
          "description": "简答题评分关键词"
        },
        "scoring_rubric": {
          "type": "string",
          "description": "简答题评分标准"
        },
        "code": {
          "type": ["string", "null"],
          "description": "代码片段（代码阅读题和场景题）"
        },
        "language": {
          "type": "string",
          "description": "编程语言（代码阅读题必填）"
        },
        "context": {
          "type": "string",
          "description": "场景描述（场景分析题必填）"
        },
        "sub_questions": {
          "type": "array",
          "items": {
            "$ref": "#/definitions/sub_question"
          },
          "description": "子问题列表（代码阅读题和场景分析题）"
        }
      },
      "allOf": [
        {
          "if": { "properties": { "type": { "const": "single_choice" } } },
          "then": {
            "required": ["options", "answer"],
            "properties": {
              "options": {
                "type": "object",
                "patternProperties": {
                  "^[A-Z]$": { "type": "string" }
                },
                "additionalProperties": false,
                "minProperties": 2
              },
              "answer": {
                "type": "string",
                "pattern": "^[A-Z]$"
              }
            }
          }
        },
        {
          "if": { "properties": { "type": { "const": "multiple_choice" } } },
          "then": {
            "required": ["options", "answer"],
            "properties": {
              "options": {
                "type": "object",
                "patternProperties": {
                  "^[A-Z]$": { "type": "string" }
                },
                "additionalProperties": false,
                "minProperties": 2
              },
              "answer": {
                "type": "array",
                "items": { "type": "string", "pattern": "^[A-Z]$" },
                "minItems": 1,
                "uniqueItems": true
              }
            }
          }
        },
        {
          "if": { "properties": { "type": { "const": "true_false" } } },
          "then": {
            "required": ["answer"],
            "properties": {
              "answer": { "type": "boolean" }
            }
          }
        },
        {
          "if": { "properties": { "type": { "const": "fill_blank" } } },
          "then": {
            "required": ["answer"],
            "properties": {
              "answer": {
                "type": "array",
                "items": { "type": "string" },
                "minItems": 1
              },
              "answer_rule": {
                "type": "string",
                "enum": ["any", "all", "ordered"],
                "default": "any"
              }
            }
          }
        },
        {
          "if": { "properties": { "type": { "const": "short_answer" } } },
          "then": {
            "required": ["answer"],
            "properties": {
              "answer": { "type": "string" },
              "keywords": {
                "type": "array",
                "items": { "type": "string" }
              },
              "scoring_rubric": { "type": "string" }
            }
          }
        },
        {
          "if": { "properties": { "type": { "const": "code_reading" } } },
          "then": {
            "required": ["code", "language", "sub_questions"],
            "properties": {
              "code": { "type": "string" },
              "language": { "type": "string" },
              "sub_questions": {
                "type": "array",
                "items": { "$ref": "#/definitions/sub_question" },
                "minItems": 1
              }
            }
          }
        },
        {
          "if": { "properties": { "type": { "const": "scenario" } } },
          "then": {
            "required": ["context", "sub_questions"],
            "properties": {
              "context": { "type": "string" },
              "code": { "type": ["string", "null"] },
              "sub_questions": {
                "type": "array",
                "items": { "$ref": "#/definitions/sub_question" },
                "minItems": 1
              }
            }
          }
        }
      ]
    },
    "sub_question": {
      "type": "object",
      "required": ["index", "type", "question", "answer", "explanation"],
      "properties": {
        "index": {
          "type": "integer",
          "minimum": 1
        },
        "type": {
          "type": "string",
          "enum": ["single_choice", "multiple_choice", "true_false", "fill_blank", "short_answer", "code_reading", "scenario"]
        },
        "question": { "type": "string" },
        "answer": {},
        "explanation": { "type": "string" },
        "options": {
          "type": "object",
          "patternProperties": {
            "^[A-Z]$": { "type": "string" }
          },
          "additionalProperties": false
        },
        "keywords": {
          "type": "array",
          "items": { "type": "string" }
        },
        "scoring_rubric": { "type": "string" }
      },
      "allOf": [
        {
          "if": { "properties": { "type": { "const": "single_choice" } } },
          "then": {
            "required": ["options"],
            "properties": {
              "options": {
                "type": "object",
                "patternProperties": {
                  "^[A-Z]$": { "type": "string" }
                },
                "additionalProperties": false,
                "minProperties": 2
              },
              "answer": {
                "type": "string",
                "pattern": "^[A-Z]$"
              }
            }
          }
        },
        {
          "if": { "properties": { "type": { "const": "multiple_choice" } } },
          "then": {
            "required": ["options"],
            "properties": {
              "options": {
                "type": "object",
                "patternProperties": {
                  "^[A-Z]$": { "type": "string" }
                },
                "additionalProperties": false,
                "minProperties": 2
              },
              "answer": {
                "type": "array",
                "items": { "type": "string", "pattern": "^[A-Z]$" },
                "minItems": 1,
                "uniqueItems": true
              }
            }
          }
        },
        {
          "if": { "properties": { "type": { "const": "true_false" } } },
          "then": {
            "properties": {
              "answer": { "type": "boolean" }
            }
          }
        },
        {
          "if": { "properties": { "type": { "const": "fill_blank" } } },
          "then": {
            "properties": {
              "answer": {
                "type": "array",
                "items": { "type": "string" },
                "minItems": 1
              }
            }
          }
        },
        {
          "if": { "properties": { "type": { "const": "short_answer" } } },
          "then": {
            "properties": {
              "answer": { "type": "string" },
              "keywords": {
                "type": "array",
                "items": { "type": "string" }
              },
              "scoring_rubric": { "type": "string" }
            }
          }
        }
      ]
    }
  }
}