{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "$id": "https://ralfspoeth.github.io/xldr/schema/mapping-spec-0.10.json",
  "title": "xldr mapping specification",
  "description": "How one input file is parsed and how its records map onto database tables. Add \"$schema\" to a spec.json to have an editor validate it; the reader ignores members it does not know.",
  "type": "object",
  "required": ["input"],
  "properties": {
    "input": { "$ref": "#/$defs/input" },
    "mapping": {
      "type": "array",
      "description": "The record mappings; a spec without any parses but loads nothing.",
      "items": { "$ref": "#/$defs/recordMapping" }
    }
  },
  "$defs": {

    "input": {
      "type": "object",
      "required": ["mimeType"],
      "description": "A feed declares exactly one of accepts or sentinel; a spec used programmatically may declare neither.",
      "oneOf": [
        { "required": ["accepts"] },
        { "required": ["sentinel"] }
      ],
      "properties": {
        "mimeType": {
          "type": "string",
          "description": "Selects the input adapter.",
          "anyOf": [
            {
              "enum": [
                "text/csv",
                "text/xml",
                "application/xml",
                "text/plain",
                "application/json",
                "text/json",
                "application/vnd.ms-excel",
                "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet"
              ]
            },
            { "type": "string" }
          ]
        },
        "accepts": {
          "$ref": "#/$defs/pattern",
          "description": "Atomic delivery: a file whose name matches triggers the load on its own, so it must be delivered atomically."
        },
        "sentinel": {
          "$ref": "#/$defs/pattern",
          "description": "Marker delivery: only a marker file matching this pattern triggers the load, of the data file named by the marker minus its last dotted suffix."
        },
        "properties": {
          "type": "object",
          "description": "Settings of the adapter the mimeType selects, e.g. fieldSeparator, header, charset, dateFormat, numberFormat, locale, linesPerRecord, ns.<prefix>. Each value is taken as its text.",
          "additionalProperties": { "type": ["string", "number", "boolean"] }
        },
        "recordSelectors": {
          "type": "array",
          "items": { "$ref": "#/$defs/recordSelector" }
        },
        "vars": {
          "type": "array",
          "description": "Values evaluated once per load and referenced from a field mapping by {\"var\": \"name\"}.",
          "items": { "$ref": "#/$defs/var" }
        }
      }
    },

    "pattern": {
      "type": "string",
      "description": "A file name pattern, in the glob: or regex: form of FileSystem.getPathMatcher.",
      "pattern": "^(glob|regex):"
    },

    "recordSelector": {
      "type": "object",
      "required": ["name"],
      "properties": {
        "name": { "type": "string", "description": "Referenced by a record mapping." },
        "selector": {
          "type": "string",
          "description": "The adapter's own syntax: an XPath, a CSV first-column discriminator, a character range, a JSON pointer, a spreadsheet range. Optional: omit it where the whole file holds one kind of record, as in a CSV with a header or a fixed-length file."
        },
        "fieldSelectors": {
          "type": "array",
          "items": { "$ref": "#/$defs/fieldSelector" }
        }
      },
      "additionalProperties": false
    },

    "fieldSelector": {
      "type": "object",
      "required": ["name", "selector"],
      "properties": {
        "name": { "type": "string", "description": "Referenced by a field mapping." },
        "selector": { "type": "string" },
        "type": { "$ref": "#/$defs/dataType" }
      },
      "additionalProperties": false
    },

    "dataType": {
      "description": "The Java type the value is delivered as; matched case-insensitively, absent means text.",
      "anyOf": [
        { "enum": ["STRING", "INTEGER", "FLOAT", "DECIMAL", "DATE"] },
        {
          "type": "string",
          "pattern": "^([Ss][Tt][Rr][Ii][Nn][Gg]|[Ii][Nn][Tt][Ee][Gg][Ee][Rr]|[Ff][Ll][Oo][Aa][Tt]|[Dd][Ee][Cc][Ii][Mm][Aa][Ll]|[Dd][Aa][Tt][Ee])$"
        }
      ]
    },

    "var": {
      "type": "object",
      "required": ["name"],
      "description": "A var is evaluated with no record in hand, so it may not read a fieldSelector.",
      "properties": {
        "name": { "type": "string" },
        "constant": { "$ref": "#/$defs/constant" },
        "var": { "type": "string" },
        "expr": { "$ref": "#/$defs/expr" },
        "lookup": { "$ref": "#/$defs/lookup" }
      },
      "oneOf": [
        { "required": ["constant"] },
        { "required": ["var"] },
        { "required": ["expr"] },
        { "required": ["lookup"] }
      ],
      "additionalProperties": false
    },

    "recordMapping": {
      "type": "object",
      "required": ["recordSelector", "table"],
      "properties": {
        "recordSelector": { "type": "string", "description": "The name of a record selector of the input." },
        "table": { "type": "string" },
        "limit": {
          "type": "integer",
          "minimum": 0,
          "description": "At most this many records are inserted for this mapping."
        },
        "fieldMapping": {
          "type": "array",
          "items": { "$ref": "#/$defs/fieldMapping" }
        }
      },
      "additionalProperties": false
    },

    "fieldMapping": {
      "type": "object",
      "required": ["column"],
      "description": "One target column and exactly one source for its value.",
      "properties": {
        "column": { "type": "string" },
        "fieldSelector": { "type": "string", "description": "The name of a field selector of the record." },
        "constant": { "$ref": "#/$defs/constant" },
        "var": { "type": "string", "description": "The name of an input var." },
        "expr": { "$ref": "#/$defs/expr" },
        "lookup": { "$ref": "#/$defs/lookup" }
      },
      "oneOf": [
        { "required": ["fieldSelector"] },
        { "required": ["constant"] },
        { "required": ["var"] },
        { "required": ["expr"] },
        { "required": ["lookup"] }
      ],
      "additionalProperties": false
    },

    "lookup": {
      "type": "object",
      "required": ["table", "column", "keyColumn"],
      "description": "A value read from a reference table, keyed by exactly one source. A key matching no row yields NULL.",
      "properties": {
        "table": { "type": "string" },
        "column": { "type": "string", "description": "The column whose value is taken." },
        "keyColumn": { "type": "string", "description": "The column the key is matched against." },
        "fieldSelector": { "type": "string" },
        "constant": { "$ref": "#/$defs/constant" },
        "var": { "type": "string" },
        "expr": { "$ref": "#/$defs/expr" }
      },
      "oneOf": [
        { "required": ["fieldSelector"] },
        { "required": ["constant"] },
        { "required": ["var"] },
        { "required": ["expr"] }
      ],
      "additionalProperties": false
    },

    "constant": {
      "type": ["string", "number", "boolean", "null"],
      "description": "A fixed value; its Java type follows the JSON literal. null loads a SQL NULL into the column."
    },

    "expr": {
      "type": "string",
      "description": "A ${...} template: interpolation of xldr.* ambient values, vars and - per row - fields, plus nextval('name'[, start[, inc]]) and now().",
      "pattern": "\\$\\{"
    }
  }
}