{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "$id": "https://raw.githubusercontent.com/api-evangelist/wgl-holdings/main/json-schema/wgl-holdings-customer-account-schema.json",
  "title": "WGL Holdings Customer Account",
  "description": "Schema representing a WGL Holdings (Washington Gas / WGL Energy Services) customer account for natural gas or electricity service.",
  "type": "object",
  "properties": {
    "accountNumber": {
      "type": "string",
      "description": "Unique customer account identifier."
    },
    "serviceType": {
      "type": "string",
      "enum": ["NaturalGas", "Electricity", "DualFuel"],
      "description": "Type of energy service: natural gas, electricity, or both."
    },
    "serviceAddress": {
      "type": "object",
      "description": "Address where energy service is delivered.",
      "properties": {
        "street": { "type": "string" },
        "city": { "type": "string" },
        "state": {
          "type": "string",
          "enum": ["DC", "MD", "VA", "PA", "DE", "OH", "NJ"]
        },
        "zip": { "type": "string", "pattern": "^[0-9]{5}(-[0-9]{4})?$" }
      },
      "required": ["street", "city", "state", "zip"]
    },
    "customerType": {
      "type": "string",
      "enum": ["Residential", "Commercial", "Industrial"],
      "description": "Customer classification."
    },
    "utilityProvider": {
      "type": "string",
      "enum": ["WashingtonGas", "WGLEnergyServices"],
      "description": "Identifies whether service is regulated (Washington Gas) or retail (WGL Energy Services)."
    },
    "rateSchedule": {
      "type": "string",
      "description": "Utility tariff rate schedule code applicable to the customer."
    },
    "meterNumber": {
      "type": "string",
      "description": "The physical meter identifier at the service address."
    },
    "usageHistory": {
      "type": "array",
      "description": "Historical energy usage readings.",
      "items": {
        "type": "object",
        "properties": {
          "billingPeriodStart": {
            "type": "string",
            "format": "date",
            "description": "Start date of the billing period."
          },
          "billingPeriodEnd": {
            "type": "string",
            "format": "date",
            "description": "End date of the billing period."
          },
          "usage": {
            "type": "number",
            "minimum": 0,
            "description": "Energy consumed during the billing period."
          },
          "unit": {
            "type": "string",
            "enum": ["Therms", "CCF", "KWh"],
            "description": "Unit of measurement for energy consumption."
          },
          "billedAmount": {
            "type": "number",
            "minimum": 0,
            "description": "Dollar amount billed for the period."
          }
        },
        "required": ["billingPeriodStart", "billingPeriodEnd", "usage", "unit"]
      }
    },
    "contractDetails": {
      "type": "object",
      "description": "For WGL Energy Services retail customers: contract terms.",
      "properties": {
        "contractType": {
          "type": "string",
          "enum": ["Fixed", "Variable", "Indexed"],
          "description": "Pricing structure of the retail energy contract."
        },
        "startDate": {
          "type": "string",
          "format": "date"
        },
        "endDate": {
          "type": "string",
          "format": "date"
        },
        "pricePerUnit": {
          "type": "number",
          "minimum": 0,
          "description": "Contracted price per unit of energy."
        },
        "unit": {
          "type": "string",
          "enum": ["Therms", "KWh"]
        },
        "renewablePercentage": {
          "type": "number",
          "minimum": 0,
          "maximum": 100,
          "description": "Percentage of supply sourced from renewable energy."
        },
        "carbonNeutral": {
          "type": "boolean",
          "description": "Whether the contract includes carbon offset credits."
        }
      }
    },
    "contact": {
      "type": "object",
      "description": "Account holder contact information.",
      "properties": {
        "name": { "type": "string" },
        "email": { "type": "string", "format": "email" },
        "phone": { "type": "string" }
      }
    }
  },
  "required": ["accountNumber", "serviceType", "serviceAddress", "customerType", "utilityProvider"]
}