{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "$id": "https://open-data-protocol.org/fluid/fluid.schema.v2.0.json",
  "title": "FLUID (Federated Layered Unified Interchange Definition) Specification",
  "description": "A comprehensive, production-ready schema for FLUID data product contracts, merging rich operational details with a streamlined, developer-friendly authoring experience.",
  "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+)?$",
      "examples": ["0.1.1"]
    },
    "kind": {
      "type": "string",
      "description": "The type of data product definition.",
      "enum": [
        "DataProduct",
        "VirtualDataProduct",
        "EgressFlow",
        "IngestFlow",
        "MLModelProduct",
        "FeatureStoreProduct"
      ]
    },
    "id": {
      "type": "string",
      "description": "Globally-unique, versioned data product identifier.",
      "minLength": 1
    },
    "name": {
      "type": "string",
      "description": "Human-readable product name."
    },
    "description": {
      "type": "string",
      "description": "A brief, business-focused description of the product's purpose."
    },
    "domain": {
      "type": "string",
      "description": "The owning business domain (e.g., 'Marketing', 'Finance')."
    },
    "metadata": {
      "$ref": "#/$defs/metadata"
    },
    "consumes": {
      "description": "An optional list of input data sources required to build the product.",
      "type": "array",
      "items": {
        "$ref": "#/$defs/consume"
      }
    },
    "build": {
      "$ref": "#/$defs/build"
    },
    "exposes": {
      "description": "The public output interfaces (ports) of the data product.",
      "type": "array",
      "minItems": 1,
      "items": {
        "$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."
            },
            {
              "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."
        },
        "ref": {
          "type": "string",
          "description": "A reference to another data product (e.g., URN)."
        },
        "description": {
          "type": "string"
        }
      },
      "required": ["id", "ref"]
    },
    "build": {
      "type": "object",
      "description": "Describes the logical transformation process and its operational details.",
      "properties": {
        "engine": {
          "type": "string",
          "enum": ["sql", "python", "dbt", "dbt-cloud", "spark-sql", "spark-python"],
          "description": "The transformation engine used."
        },
        "model": {
          "type": "string",
          "description": "A reference to the specific model or script (e.g., dbt model path)."
        },
        "config": {
          "type": "object",
          "description": "Engine-specific configuration key-value pairs.",
          "additionalProperties": true
        },
        "trigger": {
          "$ref": "#/$defs/trigger"
        },
        "runtime": {
          "$ref": "#/$defs/runtime"
        },
        "retries": {
          "$ref": "#/$defs/retryPolicy"
        },
        "notifications": {
          "type": "array",
          "items": {
            "$ref": "#/$defs/notification"
          }
        }
      },
      "required": ["engine", "model"]
    },
    "expose": {
      "type": "object",
      "description": "A single output port of the data product.",
      "properties": {
        "id": {
          "type": "string",
          "description": "The unique identifier for this output port."
        },
        "type": {
          "type": "string",
          "description": "The physical type of the output (e.g., 'snowflake_table', 'bigquery_view')."
        },
        "description": {
          "type": "string"
        },
        "location": {
          "$ref": "#/$defs/location"
        },
        "tags": {
          "type": "object",
          "properties": {
            "archetype": {
              "type": "string",
              "enum": ["hub", "satellite", "link", "view", "table"],
              "description": "The modeling archetype of the port."
            },
            "relationships": {
              "type": "array",
              "items": {
                "$ref": "#/$defs/relationship"
              }
            }
          }
        },
        "schema": {
          "type": "array",
          "items": {
            "$ref": "#/$defs/column"
          }
        },
        "quality": {
          "description": "A list of quality rules specific to this port.",
          "type": "array",
          "items": {
            "$ref": "#/$defs/qualityRule"
          }
        },
        "privacy": {
          "description": "A list of privacy treatments applied to columns in this port.",
          "type": "array",
          "items": {
            "$ref": "#/$defs/privacyRule"
          }
        },
        "semantics": {
          "$ref": "#/$defs/semantics"
        }
      },
      "required": ["id", "type", "schema", "location"]
    },
    "column": {
      "type": "object",
      "properties": {
        "name": {
          "type": "string"
        },
        "type": {
          "type": "string",
          "description": "The physical data type."
        },
        "description": {
          "type": "string"
        },
        "nullable": {
          "type": "boolean",
          "default": true
        },
        "semantic": {
          "type": "string",
          "description": "Reference to an ontology term or glossary ID."
        },
        "tags": {
          "type": "array",
          "items": {
            "type": "string"
          },
          "description": "Semantic tags like 'primary_key', 'foreign_key', 'pii'."
        }
      },
      "required": ["name", "type"]
    },
    "relationship": {
      "type": "object",
      "properties": {
        "to": {
          "type": "string",
          "description": "The 'id' of the target port for the relationship."
        },
        "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", "description": "The rule to be enforced (e.g., 'not_null', 'unique', or a SQL predicate)." },
        "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", "enum": ["parquet", "delta", "iceberg", "json", "csv"] },
        "properties": {
          "type": "object",
          "description": "Technology-specific properties (e.g., project, dataset, table)."
        }
      },
      "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", "enum": ["airflow", "dbt-cloud", "databricks", "spark", "kubernetes"] },
        "resources": { "type": "object", "properties": { "cpu": { "type": "string" }, "memory": { "type": "string" } } }
      },
      "required": []
    },
    "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" }
      },
      "required": []
    },
    "accessPolicy": {
      "type": "object",
      "properties": {
        "grants": {
          "type": "array",
          "items": {
            "$ref": "#/$defs/accessGrant"
          }
        }
      }
    },
    "accessGrant": {
      "type": "object",
      "properties": {
        "principal": { "type": "string", "description": "e.g., group:analysts, user:name@company.com" },
        "permissions": { "type": "array", "items": { "type": "string", "enum": ["readData", "readMetadata", "manage"] } }
      },
      "required": []
    },
    "operations": {
      "type": "object",
      "properties": {
        "sla": { "$ref": "#/$defs/sla" },
        "lifecycle": { "$ref": "#/$defs/lifecycle" }
      }
    },
    "sla": {
      "type": "object",
      "description": "Defines the Service Level Objectives for the entire data product.",
      "properties": {
        "latencyMs": { "type": "integer", "description": "Maximum query latency in milliseconds." },
        "freshnessMinutes": { "type": "integer", "description": "Maximum data latency in minutes." },
        "availabilityPct": { "type": "number", "description": "Expected uptime percentage." }
      }
    },
    "lifecycle": {
      "type": "object",
      "properties": {
        "retentionPeriodDays": { "type": "integer" },
        "deletionPolicy": { "type": "string", "enum": ["hard-delete", "soft-delete", "anonymize"] }
      }
    },
    "security": {
      "type": "object",
      "properties": {
        "encryptionAtRest": { "type": "string", "enum": ["None", "AES256", "KMS"], "default": "AES256" },
        "encryptionInTransit": { "type": "string", "enum": ["None", "TLS1.2+", "mTLS"], "default": "TLS1.2+" }
      }
    },
    "governance": {
      "type": "object",
      "properties": {
        "rules": {
          "type": "array",
          "items": {
            "type": "object",
            "properties": {
              "name": { "type": "string" },
              "requirement": { "type": "string" }
            },
            "required": ["name", "requirement"]
          }
        }
      }
    }
  }
}