Calendar Model

The calendar model must resolve a complete LiturgicalDay: date, season, feast, fast, commemorations, readings, propers, and conflicts.

{
  "id": "calendar-eotc",
  "system": "ethiopian",
  "epoch": "amete-mihret",
  "monthCount": 13,
  "supports": ["fixed-feasts", "movable-feasts", "fasting-periods", "lectionary"]
}

Resolution Input and Output

A calendar definition is not itself a resolved day. Given a civil or liturgical date, a calendar engine produces a LiturgicalDay containing the applicable season, observances, fast, readings, and propers.

{
  "date": {
    "gregorian": "2026-01-19",
    "ethiopian": { "year": 2018, "month": 5, "day": 11 }
  },
  "season": "timkat",
  "feasts": ["timkat"],
  "activePropers": ["proper-timkat"],
  "conflicts": []
}

The example is a resolution result, not a replacement for the calendar definition. Implementations should retain the input date system and the rules or profile version used to calculate the result so it can be reproduced later.

Calendar arithmetic, feast activation, and proper conflict resolution are separate stages. A valid date conversion does not by itself prove that the correct proper won.