{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "$id": "https://tabviewer.dalagerlabs.com/schema/collection-1.schema.json",
  "title": "Songbook collection, version 1",
  "description": "A collection.json: a named list of songbooks, hosted at any URL. Book URLs resolve against the collection document's own URL, so a folder holding collection.json and its .sbk files is a complete collection. Extensions go in properties prefixed with \"x-\", which readers ignore.",
  "type": "object",
  "required": ["collection", "name", "books"],
  "properties": {
    "$schema": {
      "description": "URI of this schema, so editors can validate the file.",
      "type": "string",
      "format": "uri"
    },
    "collection": {
      "description": "Format version. An incompatible future format will use a new number.",
      "const": 1
    },
    "name": {
      "description": "Display name of the collection.",
      "$ref": "#/$defs/text"
    },
    "description": {
      "description": "One or two sentences about the collection.",
      "$ref": "#/$defs/text"
    },
    "books": {
      "description": "The songbooks, in display order.",
      "type": "array",
      "items": { "$ref": "#/$defs/book" }
    }
  },
  "patternProperties": {
    "^x-": true
  },
  "additionalProperties": false,
  "$defs": {
    "text": {
      "description": "A string with at least one non-whitespace character. Readers trim it.",
      "type": "string",
      "pattern": "\\S"
    },
    "book": {
      "type": "object",
      "required": ["url", "name"],
      "properties": {
        "url": {
          "description": "Where the songbook (a .sbk file or a songbook.json) is: a relative reference, resolved against the collection document's URL, or an absolute http(s) URL. Other schemes are rejected. The resolved URL is the book's identity: links and favourites use it, so keep it when replacing the file.",
          "type": "string",
          "format": "uri-reference",
          "pattern": "^(?:[Hh][Tt][Tt][Pp][Ss]?:|(?![A-Za-z][A-Za-z0-9+.\\-]*:))\\S(?:.*\\S)?$",
          "examples": ["week-1.sbk", "https://example.com/books/bach/songbook.json"]
        },
        "name": {
          "description": "Display name of the songbook, normally the name in its own manifest.",
          "$ref": "#/$defs/text"
        },
        "description": {
          "description": "One or two sentences about the songbook.",
          "$ref": "#/$defs/text"
        },
        "songs": {
          "description": "How many pieces the songbook holds.",
          "type": "integer",
          "minimum": 0
        },
        "size": {
          "description": "Size of the songbook file in bytes.",
          "type": "integer",
          "minimum": 0
        },
        "updated": {
          "description": "When the songbook file last changed.",
          "type": "string",
          "format": "date-time"
        }
      },
      "patternProperties": {
        "^x-": true
      },
      "additionalProperties": false
    }
  },
  "examples": [
    {
      "$schema": "https://tabviewer.dalagerlabs.com/schema/collection-1.schema.json",
      "collection": 1,
      "name": "Easy pieces, autumn term",
      "description": "One songbook a week.",
      "books": [
        {
          "url": "week-1.sbk",
          "name": "Week 1",
          "songs": 4,
          "size": 32797,
          "updated": "2026-09-30T19:04:00Z"
        }
      ]
    }
  ]
}