{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "$id": "https://open-data-protocol.org/fluid/fluid.schema.v0.4.0.json",
  "title": "FLUID (Federated Layered Unified Interchange Definition) Specification",
  "description": "A comprehensive, production-ready schema for FLUID data product contracts. Version 0.4.0 replaces the oneOf in build.transformation.properties with conditional validation to remove ambiguity, while keeping the rest of v0.3.0 verbatim.",
  "type": "object",
  "additionalProperties": false,
  "required": [
    "fluidVersion",
    "kind",
    "id",
    "name",
    "description",
    "domain",
    "metadata",
    "exposes"
  ],
  "properties": {
    "fluidVersion": {
      "type": "string",
      "description": "Version of the FLUID spec this contract adheres to.",
      "pattern": "^\\d+\\.\\d+(\\.\\d+)?$",
      "examples": [
        "0.4.0"
      ]
    },
    "kind": {
      "type": "string",
      "description": "The type of data product definition.",
      "examples": [
        "DataProduct",
        "VirtualDataProduct",
        "EgressFlow",
        "IngestFlow",
        "MLModelProduct",
        "FeatureStoreProduct"
      ]
    },
    "id": {
      "type": "string",
      "description": "Globally-unique, versioned data product identifier. Should be machine-friendly.",
      "pattern": "^[a-zA-Z0-9_.-]+$",
      "minLength": 1
    },
    "name": {
      "type": "string",
      "description": "Human-readable product name."
    },
    "description": {
      "type": "string",
      "description": "A brief, business-focused description of the product's purpose."
    },
    "domain": {
      "type": "string",
      "description": "The owning business domain (e.g., 'Marketing', 'Finance').",
      "pattern": "^[a-zA-Z0-9_.-]+$"
    },
    "metadata": {
      "$ref": "#/$defs/metadata"
    },
    "consumes": {
      "description": "An optional list of input data sources required to build the product.",
      "type": "array",
      "items": {
        "$ref": "#/$defs/consume"
      }
    },
    "build": {
      "type": "object",
      "description": "Describes the logical transformation process and its operational details.",
      "properties": {
        "transformation": {
          "type": "object",
          "properties": {
            "pattern": {
              "type": "string",
              "enum": [
                "declarative",
                "hybrid-reference",
                "embedded-logic",
                "logical-mapping"
              ],
              "default": "hybrid-reference",
              "description": "The transformation build pattern used."
            },
            "engine": {
              "type": "string",
              "description": "The transformation engine used."
            },
            "properties": {
              "type": "object",
              "description": "Pattern-specific properties for the build transformation."
            }
          },
          "required": [
            "pattern",
            "engine",
            "properties"
          ],
          "allOf": [
            {
              "if": { "properties": { "pattern": { "const": "hybrid-reference" } }, "required": ["pattern"] },
              "then": { "properties": { "properties": { "$ref": "#/$defs/hybridReferencePattern" } } }
            },
            {
              "if": { "properties": { "pattern": { "const": "declarative" } }, "required": ["pattern"] },
              "then": { "properties": { "properties": { "$ref": "#/$defs/declarativePattern" } } }
            },
            {
              "if": { "properties": { "pattern": { "const": "embedded-logic" } }, "required": ["pattern"] },
              "then": { "properties": { "properties": { "$ref": "#/$defs/embeddedLogicPattern" } } }
            },
            {
              "if": { "properties": { "pattern": { "const": "logical-mapping" } }, "required": ["pattern"] },
              "then": { "properties": { "properties": { "$ref": "#/$defs/logicalMappingPattern" } } }
            }
          ]
        },
        "execution": {
          "type": "object",
          "properties": {
            "trigger": {
              "$ref": "#/$defs/trigger"
            },
            "runtime": {
              "$ref": "#/$defs/runtime"
            },
            "retries": {
              "$ref": "#/$defs/retryPolicy"
            },
            "notifications": {
              "type": "array",
              "items": {
                "$ref": "#/$defs/notification"
              }
            }
          }
        }
      }
    },
    "exposes": {
      "description": "The public output interfaces (ports) of the data product.",
      "type": "array",
      "minItems": 1,
      "items": {
        "$ref": "#/$defs/expose"
      }
    },
    "slo": {
      "$ref": "#/$defs/sla"
    },
    "accessPolicy": {
      "$ref": "#/$defs/accessPolicy"
    },
    "operations": {
      "$ref": "#/$defs/operations"
    },
    "security": {
      "$ref": "#/$defs/security"
    },
    "governance": {
      "$ref": "#/$defs/governance"
    }
  },
  "$defs": {
    "metadata": {
      "type": "object",
      "properties": {
        "layer": {
          "type": "string",
          "enum": [
            "Bronze",
            "Silver",
            "Gold",
            "Platinum"
          ],
          "description": "The architectural layer of the data product."
        },
        "owner": {
          "description": "The team or individual responsible for the data product.",
          "oneOf": [
            {
              "type": "string",
              "description": "A contact email address for the owner.",
              "format": "email"
            },
            {
              "type": "object",
              "properties": {
                "team": {
                  "type": "string"
                },
                "email": {
                  "type": "string",
                  "format": "email"
                },
                "slack": {
                  "type": "string"
                }
              },
              "required": [
                "team"
              ]
            }
          ]
        },
        "status": {
          "type": "string",
          "enum": [
            "Development",
            "Published",
            "Deprecated"
          ],
          "default": "Development"
        },
        "tags": {
          "type": "array",
          "items": {
            "type": "string"
          },
          "description": "A list of arbitrary tags for categorization."
        }
      },
      "required": [
        "layer",
        "owner"
      ]
    },
    "consume": {
      "type": "object",
      "properties": {
        "id": {
          "type": "string",
          "description": "A local alias for the consumed data source.",
          "pattern": "^[a-zA-Z0-9_.-]+$"
        },
        "ref": {
          "type": "string",
          "description": "A reference to another data product (e.g., URN)."
        },
        "description": {
          "type": "string"
        }
      },
      "required": [
        "id",
        "ref"
      ]
    },
    "expose": {
      "type": "object",
      "description": "A single output port of the data product.",
      "properties": {
        "id": {
          "type": "string",
          "description": "The unique identifier for this output port.",
          "pattern": "^[a-zA-Z0-9_.-]+$"
        },
        "type": {
          "type": "string",
          "description": "The physical type of the output."
        },
        "description": {
          "type": "string"
        },
        "location": {
          "$ref": "#/$defs/location"
        },
        "tags": {
          "type": "object",
          "properties": {
            "archetype": {
              "type": "string",
              "enum": [
                "hub",
                "satellite",
                "link",
                "view",
                "table"
              ]
            },
            "relationships": {
              "type": "array",
              "items": {
                "$ref": "#/$defs/relationship"
              }
            }
          }
        },
        "schema": {
          "type": "array",
          "items": {
            "$ref": "#/$defs/column"
          }
        },
        "mappings": {
          "description": "OPTIONAL. Column-level lineage and rules for governance. SHOULD be generated from build.transformation, not manually maintained.",
          "type": "array",
          "items": {
            "$ref": "#/$defs/mapping"
          },
          "readOnly": true
        },
        "quality": {
          "type": "array",
          "items": {
            "$ref": "#/$defs/qualityRule"
          }
        },
        "privacy": {
          "type": "array",
          "items": {
            "$ref": "#/$defs/privacyRule"
          }
        },
        "semantics": {
          "$ref": "#/$defs/semantics"
        }
      },
      "required": [
        "id",
        "type",
        "schema",
        "location"
      ]
    },
    "mapping": {
      "type": "object",
      "properties": {
        "target": {
          "type": "string",
          "pattern": "^[a-zA-Z0-9_]+$"
        },
        "sources": {
          "type": "array",
          "items": {
            "type": "string"
          }
        },
        "rule": {
          "type": "string"
        }
      },
      "required": [
        "target",
        "sources",
        "rule"
      ]
    },
    "declarativePattern": {
      "type": "object",
      "properties": {
        "from": {
          "type": "string"
        },
        "joins": {
          "type": "array",
          "items": {
            "$ref": "#/$defs/join"
          }
        },
        "filters": {
          "type": "array",
          "items": {
            "type": "string"
          }
        },
        "select": {
          "type": "array",
          "items": {
            "$ref": "#/$defs/select"
          }
        }
      }
    },
    "hybridReferencePattern": {
      "type": "object",
      "properties": {
        "model": {
          "type": "string"
        },
        "vars": {
          "type": "object",
          "additionalProperties": true
        }
      },
      "required": [
        "model"
      ]
    },
    "embeddedLogicPattern": {
      "type": "object",
      "properties": {
        "sql": {
          "type": "string"
        },
        "language": {
          "type": "string",
          "enum": [
            "sql",
            "flink_sql",
            "pyspark",
            "scala"
          ]
        }
      },
      "required": [
        "sql"
      ]
    },
    "logicalMappingPattern": {
      "type": "object",
      "properties": {
        "sources": {
          "type": "array",
          "items": {
            "type": "string"
          }
        },
        "steps": {
          "type": "array",
          "items": {
            "$ref": "#/$defs/step"
          }
        }
      }
    },
    "join": {
      "type": "object",
      "properties": {
        "type": {
          "type": "string",
          "enum": [
            "inner",
            "left",
            "right",
            "full"
          ]
        },
        "left": {
          "type": "string"
        },
        "right": {
          "type": "string"
        },
        "on": {
          "type": "string"
        }
      },
      "required": [
        "type",
        "left",
        "right",
        "on"
      ]
    },
    "select": {
      "type": "object",
      "properties": {
        "name": {
          "type": "string"
        },
        "source": {
          "type": "string"
        },
        "expression": {
          "type": "string"
        }
      },
      "required": [
        "name"
      ]
    },
    "step": {
      "type": "object",
      "properties": {
        "type": {
          "type": "string",
          "enum": [
            "join",
            "filter",
            "project",
            "aggregate"
          ]
        },
        "source": {
          "type": "string"
        },
        "condition": {
          "type": "string"
        },
        "output": {
          "type": "string"
        }
      },
      "required": [
        "type"
      ]
    },
    "column": {
      "type": "object",
      "properties": {
        "name": {
          "type": "string",
          "pattern": "^[a-zA-Z0-9_]+$"
        },
        "type": {
          "type": "string"
        },
        "description": {
          "type": "string"
        },
        "nullable": {
          "type": "boolean",
          "default": true
        },
        "semantic": {
          "type": "string"
        },
        "tags": {
          "type": "array",
          "items": {
            "type": "string"
          }
        }
      },
      "required": [
        "name",
        "type"
      ]
    },
    "relationship": {
      "type": "object",
      "properties": {
        "to": {
          "type": "string"
        },
        "cardinality": {
          "type": "string",
          "enum": [
            "one-to-one",
            "one-to-many",
            "many-to-one",
            "many-to-many"
          ]
        },
        "description": {
          "type": "string"
        }
      },
      "required": [
        "to",
        "cardinality"
      ]
    },
    "qualityRule": {
      "type": "object",
      "properties": {
        "name": {
          "type": "string"
        },
        "rule": {
          "type": "string"
        },
        "onFailure": {
          "type": "object",
          "properties": {
            "action": {
              "type": "string",
              "enum": [
                "reject_row",
                "quarantine_row",
                "fail_pipeline",
                "alert"
              ]
            }
          },
          "required": [
            "action"
          ]
        }
      },
      "required": [
        "name",
        "rule",
        "onFailure"
      ]
    },
    "privacyRule": {
      "type": "object",
      "properties": {
        "classification": {
          "type": "string",
          "enum": [
            "PII",
            "SPI",
            "Confidential"
          ]
        },
        "columns": {
          "type": "array",
          "items": {
            "type": "string"
          }
        },
        "treatment": {
          "type": "object",
          "properties": {
            "type": {
              "type": "string",
              "enum": [
                "hashing",
                "masking",
                "encryption",
                "tokenization"
              ]
            }
          },
          "required": [
            "type"
          ]
        }
      },
      "required": [
        "columns",
        "treatment"
      ]
    },
    "semantics": {
      "type": "object",
      "properties": {
        "ontology": {
          "type": "string",
          "format": "uri"
        },
        "classifications": {
          "type": "object",
          "additionalProperties": {
            "type": "string"
          }
        }
      }
    },
    "location": {
      "type": "object",
      "properties": {
        "format": {
          "type": "string"
        },
        "properties": {
          "type": "object",
          "description": "Technology-specific properties (e.g., dataset, table, bucket)."
        }
      },
      "required": [
        "properties"
      ]
    },
    "trigger": {
      "type": "object",
      "description": "Defines how the build is initiated.",
      "oneOf": [
        {
          "properties": {
            "type": {
              "const": "schedule"
            },
            "cron": {
              "type": "string"
            }
          },
          "required": [
            "type",
            "cron"
          ]
        },
        {
          "properties": {
            "type": {
              "const": "event"
            },
            "eventType": {
              "type": "string"
            }
          },
          "required": [
            "type",
            "eventType"
          ]
        },
        {
          "properties": {
            "type": {
              "const": "manual"
            }
          },
          "required": [
            "type"
          ]
        }
      ]
    },
    "runtime": {
      "type": "object",
      "properties": {
        "platform": {
          "type": "string"
        },
        "resources": {
          "type": "object",
          "properties": {
            "cpu": {
              "type": "string"
            },
            "memory": {
              "type": "string"
            }
          }
        }
      }
    },
    "retryPolicy": {
      "type": "object",
      "properties": {
        "count": {
          "type": "integer",
          "minimum": 0,
          "default": 0
        },
        "delaySeconds": {
          "type": "integer",
          "minimum": 0,
          "default": 0
        },
        "backoff": {
          "type": "string",
          "enum": [
            "none",
            "exponential"
          ],
          "default": "none"
        }
      }
    },
    "notification": {
      "type": "object",
      "properties": {
        "channel": {
          "type": "string",
          "enum": [
            "email",
            "slack",
            "pagerduty",
            "webhook"
          ]
        },
        "target": {
          "type": "string"
        }
      }
    },
    "accessPolicy": {
      "type": "object",
      "properties": {
        "grants": {
          "type": "array",
          "items": {
            "$ref": "#/$defs/accessGrant"
          }
        }
      }
    },
    "accessGrant": {
      "type": "object",
      "properties": {
        "principal": {
          "type": "string"
        },
        "permissions": {
          "type": "array",
          "items": {
            "type": "string",
            "enum": [
              "readData",
              "readMetadata",
              "manage"
            ]
          }
        }
      }
    },
    "operations": {
      "type": "object",
      "properties": {
        "sla": {
          "$ref": "#/$defs/sla"
        },
        "lifecycle": {
          "$ref": "#/$defs/lifecycle"
        }
      }
    },
    "sla": {
      "type": "object",
      "properties": {
        "latencyMs": {
          "type": "integer",
          "minimum": 0
        },
        "freshnessMinutes": {
          "type": "integer",
          "minimum": 0
        },
        "availabilityPct": {
          "type": "number",
          "minimum": 0,
          "maximum": 100
        }
      }
    },
    "lifecycle": {
      "type": "object",
      "properties": {
        "retentionPeriodDays": {
          "type": "integer",
          "minimum": 0
        },
        "deletionPolicy": {
          "type": "string",
          "enum": [
            "hard-delete",
            "soft-delete",
            "anonymize"
          ]
        }
      }
    },
    "security": {
      "type": "object",
      "properties": {
        "encryptionAtRest": {
          "type": "string",
          "default": "AES256"
        },
        "encryptionInTransit": {
          "type": "string",
          "default": "TLS1.2+"
        }
      }
    },
    "governance": {
      "type": "object",
      "properties": {
        "lineage": {
          "type": "string"
        },
        "regulatory": {
          "type": "array",
          "items": {
            "type": "string",
            "enum": [
              "GDPR",
              "CCPA",
              "HIPAA",
              "SOX"
            ]
          }
        },
        "stewardship": {
          "type": "object",
          "properties": {
            "steward": {
              "type": "string"
            },
            "email": {
              "type": "string",
              "format": "email"
            }
          }
        }
      }
    }
  }
}