{
    "$schema": "http://json-schema.org/draft-07/schema",
    "$id": "https://github.com/FGPE-Erasmus/format-specifications/blob/master/schemas/yapexil.schema.json",
    "title": "Yet Another Programming Exercise Interoperability Language",
    "description": "JSON schema for describing a programming exercise package, based on PExIL - an XML dialect that aims to consolidate all the data required in the programming exercise life-cycle. YAPExIL aims for simplicity while covering most features of a task package as described by Verhoeff's model, i.e., a unit for collecting, storing, archiving, and exchanging all information concerning with a programming task.",
    "type": "object",
    "required": [
        "id",
        "title",
        "author",
        "keywords",
        "status",
        "type",
        "created_at",
        "statements",
        "solutions",
        "tests"
    ],
    "properties": {
        "id": {
            "title": "ID",
            "description": "UUID of the exercise.",
            "type": "string",
            "format": "uuid"
        },
        "title": {
            "title": "Title",
            "description": "Title of the exercise.",
            "type": "string"
        },
        "module": {
            "title": "Module",
            "description": "Module in which the exercise is in (description of its main topic).",
            "type": "string"
        },
        "author": {
            "title": "Author",
            "description": "Author of the exercise.",
            "type": "string"
        },
        "keywords": {
            "title": "Keywords",
            "description": "Keywords of the exercise.",
            "type": "array",
            "items": {
                "maxLength": 50,
                "type": "string"
            }
        },
        "type": {
            "title": "Type",
            "description": "The type of programming exercise to be solved.",
            "type": "string",
            "enum": [
                "BLANK_SHEET",
                "EXTENSION",
                "IMPROVEMENT",
                "BUG_FIX",
                "FILL_IN_GAPS",
                "SORT_BLOCKS",
                "SPOT_BUG"
            ],
            "default": "BLANK_SHEET"
        },
        "event": {
            "title": "Event",
            "description": "Event at which the exercise was created (if any).",
            "type": "string"
        },
        "platform": {
            "title": "Platform",
            "description": "Platform requirements (if any).",
            "type": "string"
        },
        "difficulty": {
            "title": "Difficulty",
            "description": "Difficulty of the exercise.",
            "type": "string",
            "enum": [
                "BEGINNER",
                "EASY",
                "AVERAGE",
                "HARD",
                "MASTER"
            ]
        },
        "timeout": {
            "title": "Timeout",
            "description": "Timeout of the exercise.",
            "type": "number",
            "default": -1
        },
        "programmingLanguages": {
            "title": "Programming Languages",
            "description": "Programming languages in which the code can be written.",
            "type": "array",
            "items": {
                "maxLength": 50,
                "type": "string"
            },
            "default": []
        },
        "status": {
            "title": "Status",
            "description": "Status of the exercise.",
            "type": "string",
            "enum": [
                "DRAFT",
                "PUBLISHED",
                "UNPUBLISHED",
                "TRASH"
            ],
            "default": "DRAFT"
        },
        "created_at": {
            "title": "Creation Date",
            "description": "Date of creation of the exercise.",
            "type": "string",
            "format": "date-time"
        },
        "updated_at": {
            "title": "Last Update Date",
            "description": "Date of the last update to the exercise.",
            "type": "string",
            "format": "date-time"
        },
        "instructions": {
            "title": "Instructions",
            "description": "Instructions to teachers about the exercise.",
            "type": "array",
            "items": {
                "$ref": "#/definitions/FormattedText"
            },
            "default": []
        },
        "statements": {
            "title": "Statements",
            "description": "The statement of the exercise to present to the student in the various languages.",
            "type": "array",
            "items": {
                "$ref": "#/definitions/FormattedText"
            },
            "minItems": 1
        },
        "embeddables": {
            "title": "Embeddables",
            "description": "Images, videos, and other files that can be embedded in the statement.",
            "type": "array",
            "items": {
                "$ref": "#/definitions/Resource"
            },
            "default": []
        },
        "libraries": {
            "title": "Libraries",
            "description": "Code libraries that can be used by solutions. It may be used during compilation and/or execution phases.",
            "type": "array",
            "items": {
                "$ref": "#/definitions/Resource"
            },
            "default": []
        },
        "static_correctors": {
            "title": "Static Correctors",
            "description": "External programs that are invoked before dynamic correction to classify/process the program's source code.",
            "type": "array",
            "items": {
                "$ref": "#/definitions/Executable"
            },
            "default": []
        },
        "dynamic_correctors": {
            "title": "Dynamic Correctors",
            "description": "External programs that are invoked after the main correction to classify each run.",
            "type": "array",
            "items": {
                "$ref": "#/definitions/Executable"
            },
            "default": []
        },
        "test_generators": {
            "title": "Test Generators",
            "description": "External programs that generate the test cases to validate a solution.",
            "type": "array",
            "items": {
                "$ref": "#/definitions/Executable"
            },
            "default": []
        },
        "feedback_generators": {
            "title": "Feedback Generators",
            "description": "External programs that generate the feedback to give to the student about his/her attempt to achieve a solution.",
            "type": "array",
            "items": {
                "$ref": "#/definitions/Executable"
            },
            "default": []
        },
        "skeletons": {
            "title": "Skeletons",
            "description": "Part of a solution that is provided to the students.",
            "type": "array",
            "items": {
                "$ref": "#/definitions/Code"
            },
            "default": []
        },
        "solutions": {
            "title": "Solutions",
            "description": "Solutions provided by the author(s) of the exercise.",
            "type": "array",
            "items": {
                "$ref": "#/definitions/Code"
            },
            "default": []
        },
        "templates": {
            "title": "Templates",
            "description": "Part of a solution that wraps students' code without their awareness.",
            "type": "array",
            "items": {
                "$ref": "#/definitions/Code"
            },
            "default": []
        },
        "tests": {
            "title": "Tests",
            "description": "Test cases to validate if attempts are correct.",
            "type": "array",
            "items": {
                "$ref": "#/definitions/Test"
            },
            "minItems": 0
        },
        "testsets": {
            "title": "Test Sets",
            "description": "Set(s) of test cases to validate if attempts are correct.",
            "type": "array",
            "items": {
                "$ref": "#/definitions/TestSet"
            },
            "minItems": 0
        }
    },
    "definitions": {
        "Test": {
            "title": "Test",
            "description": "Test case to validate if the attempt is correct.",
            "type": "object",
            "properties": {
                "id": {
                    "title": "ID",
                    "description": "ID of the test.",
                    "type": "string",
                    "format": "uuid"
                },
                "name": {
                    "title": "Name",
                    "description": "Name of the test (e.g., T002).",
                    "type": "string"
                },
                "input": {
                    "title": "Input",
                    "description": "File with input of the test.",
                    "type": "string"
                },
                "output": {
                    "title": "Output",
                    "description": "File with expected output of the test.",
                    "type": "string"
                },
                "arguments": {
                    "title": "Arguments",
                    "description": "Additional arguments provided to the program when running this test.",
                    "type": "array",
                    "items": {
                        "type": "string"
                    },
                    "default": []
                },
                "weight": {
                    "title": "Weight",
                    "description": "Weight of this test in overall evaluation.",
                    "type": "number"
                },
                "visible": {
                    "title": "Visible",
                    "description": "Is this test visible to the user?",
                    "type": "boolean",
                    "default": false
                },
                "timeout": {
                    "title": "Timeout",
                    "description": "Timeout of this test.",
                    "type": "number",
                    "default": -1
                },
                "feedback": {
                    "title": "Feedback",
                    "description": "Feedback messages associated with the test.",
                    "type": "array",
                    "items": {
                        "$ref": "#/definitions/Feedback"
                    }

                }
            },
            "required": [
                "input",
                "output",
                "visible"
            ]
        },
        "TestSet": {
            "title": "Test Set",
            "description": "A set of test cases to validate if the attempt is correct.",
            "type": "object",
            "properties": {
                "id": {
                    "title": "ID",
                    "description": "ID of the test set.",
                    "type": "string",
                    "format": "uuid"
                },
                "name": {
                    "title": "Name",
                    "description": "Name of the test set.",
                    "type": "string"
                },
                "tests": {
                    "title": "Tests",
                    "description": "Set of test cases.",
                    "type": "array",
                    "items": {
                        "$ref": "#/definitions/Test"
                    },
                    "minItems": 1
                },
                "weight": {
                    "title": "Weight",
                    "description": "Weight of the test set in overall evaluation.",
                    "type": "number"
                },
                "visible": {
                    "title": "Visible",
                    "description": "Is this test set visible to the user?",
                    "type": "boolean",
                    "default": false
                }
            },
            "required": [
                "tests",
                "visible"
            ]
        },
        "FormattedText": {
            "title": "FormattedText",
            "description": "An external file with formatted text.",
            "type": "object",
            "properties": {
                "pathname": {
                    "title": "Pathname",
                    "description": "Path to file in the archive.",
                    "type": "string"
                },
                "format": {
                    "title": "Format",
                    "description": "Format used in this file.",
                    "enum": [
                        "PDF",
                        "MARKDOWN",
                        "HTML",
                        "TXT"
                    ],
                    "type": "string"
                },
                "nat_lang": {
                    "title": "Natural Language",
                    "description": "Natural language in which the text is written.",
                    "type": "string"
                }
            },
            "required": [
                "pathname",
                "format",
                "nat_lang"
            ]
        },
        "Resource": {
            "title": "Resource",
            "description": "An external file used in the exercise.",
            "type": "object",
            "properties": {
                "pathname": {
                    "title": "Pathname",
                    "description": "Path to file in the archive.",
                    "type": "string"
                },
                "type": {
                    "title": "Type",
                    "description": "Type of resource.",
                    "enum": [
                        "EMBEDDABLE",
                        "LIBRARY"
                    ],
                    "type": "string"
                }
            },
            "required": [
                "pathname",
                "type"
            ]
        },
        "Executable": {
            "title": "Executable",
            "description": "An external file that is an executable program.",
            "type": "object",
            "properties": {
                "pathname": {
                    "title": "Pathname",
                    "description": "Path to file in the archive.",
                    "type": "string"
                },
                "command_line": {
                    "title": "Command Line",
                    "description": "The command line to run this executable.",
                    "type": "string"
                }
            },
            "required": [
                "pathname",
                "command_line"
            ]
        },
        "Code": {
            "title": "Code",
            "description": "An external file that contains code in a certain programming language",
            "type": "object",
            "properties": {
                "pathname": {
                    "title": "Pathname",
                    "description": "Path to file in the archive.",
                    "type": "string"
                },
                "lang": {
                    "title": "Programming Language",
                    "description": "Programming language in which the code is written.",
                    "type": "string"
                }
            },
            "required": [
                "pathname",
                "lang"
            ]
        },
        "Feedback": {
            "title": "Feedback",
            "description": "Feedback messages associated with the test.",
            "type": "object",
            "properties": {
                "message": {
                    "title": "Message",
                    "description": "The message.",
                    "type": "string"
                },
                "weight": {
                    "title": "Weight",
                    "description": "The weight of this message.",
                    "type": "number"
                }
            },
            "required": [
                "message"
            ]
        }
    }
}