{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "$id": "trainlog-ai-session-drafts-v1.schema.json",
  "title": "PC to Android AI session drafts companion",
  "type": "object",
  "additionalProperties": false,
  "required": ["format", "version", "generated_at", "drafts"],
  "properties": {
    "format": {"const": "trainlog-ai-session-drafts"},
    "version": {"const": 1},
    "generated_at": {"type": "string", "pattern": "^[0-9]{4}-[0-9]{2}-[0-9]{2}T[0-9]{2}:[0-9]{2}:[0-9]{2}Z$"},
    "drafts": {"type": "array", "maxItems": 256, "items": {"$ref": "#/$defs/draft"}}
  },
  "$defs": {
    "target": {
      "type": "object", "additionalProperties": false,
      "required": ["sets", "reps", "duration_seconds", "weight_kg"],
      "properties": {
        "sets": {"type": "integer", "minimum": 1, "maximum": 99},
        "reps": {"type": ["integer", "null"], "minimum": 1, "maximum": 999},
        "duration_seconds": {"type": ["integer", "null"], "minimum": 1, "maximum": 86400},
        "weight_kg": {"type": ["number", "null"], "exclusiveMinimum": 0, "maximum": 10000}
      }
    },
    "entry": {
      "type": "object", "additionalProperties": false,
      "required": ["entry_id", "position", "exercise_id", "recording_mode", "tracking_mode", "data_fields", "equipment_id", "load_mode", "rest_seconds", "target"],
      "properties": {
        "entry_id": {"type": "string", "pattern": "^sxe_[0-9a-f]{8}-[0-9a-f]{4}-4[0-9a-f]{3}-[89ab][0-9a-f]{3}-[0-9a-f]{12}$"},
        "position": {"type": "integer", "minimum": 0, "maximum": 63},
        "exercise_id": {"type": "string", "pattern": "^ex_[0-9a-f]{8}-[0-9a-f]{4}-4[0-9a-f]{3}-[89ab][0-9a-f]{3}-[0-9a-f]{12}$"},
        "recording_mode": {"const": "sets"},
        "tracking_mode": {"enum": ["reps", "duration"]},
        "data_fields": {"type": "integer", "minimum": 0, "maximum": 3},
        "equipment_id": {"type": ["string", "null"]},
        "load_mode": {"enum": ["none", "external"]},
        "rest_seconds": {"type": "integer", "minimum": 0, "maximum": 86400},
        "target": {"$ref": "#/$defs/target"}
      }
    },
    "draft": {
      "type": "object", "additionalProperties": false,
      "required": ["draft_id", "created_at", "planned_for", "session_type", "title", "notes", "entries"],
      "properties": {
        "draft_id": {"type": "string", "pattern": "^aid_[0-9a-f]{8}-[0-9a-f]{4}-4[0-9a-f]{3}-[89ab][0-9a-f]{3}-[0-9a-f]{12}$"},
        "created_at": {"type": "string"},
        "planned_for": {"type": ["string", "null"]},
        "session_type": {"const": "training"},
        "title": {"type": ["string", "null"], "maxLength": 120},
        "notes": {"type": ["string", "null"], "maxLength": 2000},
        "entries": {"type": "array", "minItems": 1, "maxItems": 64, "items": {"$ref": "#/$defs/entry"}}
      }
    }
  }
}