{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "$id":     "https://civitasconnect.digital/core/datasource/v1",
  "title":   "CORE DataSource",
  "description": "Configuration for a data source that feeds data into a CORE pipeline. The connector-specific fields are chosen by 'connectionType' (mqtt | sql); each variant declares exactly the fields the host persists (the connector configuration POJO). Only 'password' is stored ENCRYPTED by the host — every other field is stored as-is. 'element' references the DataStructure describing the payload format by versioned CORE URN.",
  "oneOf": [
    { "$ref": "#/$defs/MqttDataSource" },
    { "$ref": "#/$defs/SqlDataSource" }
  ],
  "$defs": {
    "MqttDataSource": {
      "type": "object",
      "title": "MQTT DataSource",
      "description": "Subscribes to one or more MQTT brokers and topics.",
      "required": ["$schema", "id", "connectionType"],
      "additionalProperties": false,
      "properties": {
        "$schema": {
          "type": "string",
          "enum": [
            "https://civitasconnect.digital/core/datasource/v1",
            "https://civitasconnect.digital/core-dataset/v1#/$defs/DataSource"
          ]
        },
        "id": {
          "type": "string",
          "description": "Versioned CORE URN of this DataSource.",
          "pattern": "^urn:core:[^:]+:[^:]+:datasource:[^:]+:[^:]+:[^:]+(:[^:]+)?$"
        },
        "title":       { "type": "string", "description": "Human-readable display name." },
        "description": { "type": "string" },
        "connectionType": { "const": "mqtt", "description": "MQTT broker subscription source." },
        "element": {
          "type": "string",
          "description": "Versioned CORE URN of the DataStructure that describes the payload format.",
          "pattern": "^urn:core:[^:]+:[^:]+:(datastructure|element):[^:]+:[^:]+:[^:]+(:[^:]+)?$",
          "x-core-ref": { "type": "urn:core:type:DataStructure" }
        },
        "urls":   { "type": ["array", "null"], "items": { "type": "string" }, "description": "MQTT broker URLs, e.g. 'mqtt://mosquitto:1883'." },
        "topics": { "type": ["array", "null"], "items": { "type": "string" }, "description": "MQTT topic filter(s) to subscribe to. Wildcards (+, #) are supported." },
        "qos":             { "enum": [0, 1, 2, null], "description": "MQTT Quality of Service level: 0, 1 or 2." },
        "protocol_version": { "enum": ["3", "5", null], "description": "MQTT protocol version: '3' (auto-select 3.1 or 3.1.1) or '5' (5.0)." },
        "connect_timeout": { "type": ["string", "null"], "description": "Connection timeout, e.g. '5s'." },
        "keepalive":       { "type": ["string", "null"], "description": "Keep-alive interval, e.g. '30s'." },
        "tls": {
          "type": ["object", "null"],
          "additionalProperties": false,
          "properties": { "enabled": { "type": "boolean" } },
          "description": "TLS settings for the broker connection."
        },
        "user":     { "type": ["string", "null"], "description": "MQTT username." },
        "password": { "type": ["string", "null"], "description": "MQTT password. Stored ENCRYPTED by the host; null/absent when unset." }
      }
    },
    "SqlDataSource": {
      "type": "object",
      "title": "SQL DataSource",
      "description": "Polls a relational database via a JDBC/SQL query.",
      "required": ["$schema", "id", "connectionType"],
      "additionalProperties": false,
      "properties": {
        "$schema": {
          "type": "string",
          "enum": [
            "https://civitasconnect.digital/core/datasource/v1",
            "https://civitasconnect.digital/core-dataset/v1#/$defs/DataSource"
          ]
        },
        "id": {
          "type": "string",
          "description": "Versioned CORE URN of this DataSource.",
          "pattern": "^urn:core:[^:]+:[^:]+:datasource:[^:]+:[^:]+:[^:]+(:[^:]+)?$"
        },
        "title":       { "type": "string", "description": "Human-readable display name." },
        "description": { "type": "string" },
        "connectionType": { "const": "sql", "description": "SQL/JDBC polling source." },
        "element": {
          "type": "string",
          "description": "Versioned CORE URN of the DataStructure that describes the row format.",
          "pattern": "^urn:core:[^:]+:[^:]+:(datastructure|element):[^:]+:[^:]+:[^:]+(:[^:]+)?$",
          "x-core-ref": { "type": "urn:core:type:DataStructure" }
        },
        "driver":  { "type": ["string", "null"], "description": "Database driver, e.g. 'postgres'. Only 'postgres' is wired in the NiFi engine." },
        "dsn":     { "type": ["string", "null"], "description": "Connection URL / data-source name (embedded credentials are stripped)." },
        "table":   { "type": ["string", "null"], "description": "Table to poll." },
        "columns": { "type": ["array", "null"], "items": { "type": "string" }, "description": "Columns to select." },
        "where":   { "type": ["string", "null"], "description": "SQL WHERE clause." },
        "user":     { "type": ["string", "null"], "description": "Database login username." },
        "password": { "type": ["string", "null"], "description": "Database login password. Stored ENCRYPTED by the host; null/absent when unset." }
      }
    }
  }
}