{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "$id": "https://open-data-protocol.org/fluid/fluid.schema.v0.3.0.json",
  "title": "FLUID (Federated Layered Unified Interchange Definition) Specification",
  "description": "A comprehensive, production-ready schema for FLUID data product contracts. Version 0.3.0 introduces support for multiple Build Patterns (Declarative, Hybrid Reference, Embedded Logic, Logical Mapping) and clarifies that exposes.mappings should be treated as derivative metadata, not the source of truth.",
  "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+)?$",
      "examples": ["0.3.0"]
    },
    "kind": {
      "type": "string",
      "description": "The type of data product definition.",
      "examples": [
        "DataProduct",
        "VirtualDataProduct",
        "EgressFlow",
        "IngestFlow",
        "MLModelProduct",
        "FeatureStoreProduct"
      ]
    },
    "id": {
      "type": "string",
      "description": "Globally-unique, versioned data product identifier. Should be machine-friendly.",
      "pattern": "^[a-zA-Z0-9_.-]+$",
      "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": "#/$defs/consume"
      }
    },
    "build": {
      "type": "object",
      "description": "Describes the logical transformation process and its operational details.",
      "properties": {
        "transformation": {
          "type": "object",
          "properties": {
            "pattern": {
              "type": "string",
              "enum": ["declarative", "hybrid-reference", "embedded-logic", "logical-mapping"],
              "default": "hybrid-reference",
              "description": "The transformation build pattern used."
            },
            "engine": {
              "type": "string",
              "description": "The transformation engine used."
            },
            "properties": {
              "type": "object",
              "description": "Pattern-specific properties for the build transformation.",
              "oneOf": [
                { "$ref": "#/$defs/declarativePattern" },
                { "$ref": "#/$defs/hybridReferencePattern" },
                { "$ref": "#/$defs/embeddedLogicPattern" },
                { "$ref": "#/$defs/logicalMappingPattern" }
              ]
            }
          },
          "required": ["pattern", "engine", "properties"]
        },
        "execution": {
          "type": "object",
          "properties": {
            "trigger": { "$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" }
          }
        }
      }
    }
  }
}