{
  "$schema": "http://json-schema.org/draft-07/schema#",
  "$id": "https://atomizer.io/schemas/atomizer_spec_v2.json",
  "title": "AtomizerSpec v2.0",
  "description": "Unified configuration schema for Atomizer optimization studies. This is the single source of truth used by Canvas, Backend, Claude, and the Optimization Engine.",
  "type": "object",
  "required": ["meta", "model", "design_variables", "extractors", "objectives", "optimization"],

  "properties": {
    "meta": {
      "$ref": "#/definitions/meta"
    },
    "model": {
      "$ref": "#/definitions/model"
    },
    "design_variables": {
      "type": "array",
      "description": "Design variables (NX expressions) to optimize",
      "minItems": 1,
      "maxItems": 50,
      "items": {
        "$ref": "#/definitions/design_variable"
      }
    },
    "extractors": {
      "type": "array",
      "description": "Physics extractors that compute outputs from FEA results",
      "minItems": 1,
      "items": {
        "$ref": "#/definitions/extractor"
      }
    },
    "objectives": {
      "type": "array",
      "description": "Optimization objectives (minimize/maximize)",
      "minItems": 1,
      "maxItems": 5,
      "items": {
        "$ref": "#/definitions/objective"
      }
    },
    "constraints": {
      "type": "array",
      "description": "Hard and soft constraints",
      "items": {
        "$ref": "#/definitions/constraint"
      }
    },
    "optimization": {
      "$ref": "#/definitions/optimization"
    },
    "workflow": {
      "$ref": "#/definitions/workflow"
    },
    "reporting": {
      "$ref": "#/definitions/reporting"
    },
    "canvas": {
      "$ref": "#/definitions/canvas"
    }
  },

  "definitions": {
    "meta": {
      "type": "object",
      "description": "Metadata about the spec",
      "required": ["version", "study_name"],
      "properties": {
        "version": {
          "type": "string",
          "description": "Schema version",
          "pattern": "^2\\.\\d+$",
          "examples": ["2.0", "2.1"]
        },
        "created": {
          "type": "string",
          "format": "date-time",
          "description": "When the spec was created"
        },
        "modified": {
          "type": "string",
          "format": "date-time",
          "description": "When the spec was last modified"
        },
        "created_by": {
          "type": "string",
          "description": "Who/what created the spec",
          "enum": ["canvas", "claude", "api", "migration", "manual"]
        },
        "modified_by": {
          "type": "string",
          "description": "Who/what last modified the spec"
        },
        "study_name": {
          "type": "string",
          "description": "Unique study identifier (snake_case)",
          "pattern": "^[a-z0-9_]+$",
          "minLength": 3,
          "maxLength": 100
        },
        "description": {
          "type": "string",
          "description": "Human-readable description of the study",
          "maxLength": 1000
        },
        "tags": {
          "type": "array",
          "description": "Tags for categorization",
          "items": {
            "type": "string",
            "maxLength": 50
          }
        },
        "engineering_context": {
          "type": "string",
          "description": "Real-world engineering scenario"
        }
      }
    },

    "model": {
      "type": "object",
      "description": "NX model files and configuration",
      "required": ["sim"],
      "properties": {
        "nx_part": {
          "type": "object",
          "description": "NX geometry part file",
          "properties": {
            "path": {
              "type": "string",
              "description": "Path to .prt file"
            },
            "hash": {
              "type": "string",
              "description": "File hash for change detection"
            },
            "idealized_part": {
              "type": "string",
              "description": "Idealized part filename (_i.prt)"
            }
          }
        },
        "fem": {
          "type": "object",
          "description": "FEM mesh file",
          "properties": {
            "path": {
              "type": "string",
              "description": "Path to .fem file"
            },
            "element_count": {
              "type": "integer",
              "description": "Number of elements"
            },
            "node_count": {
              "type": "integer",
              "description": "Number of nodes"
            }
          }
        },
        "sim": {
          "type": "object",
          "description": "Simulation file",
          "required": ["path", "solver"],
          "properties": {
            "path": {
              "type": "string",
              "description": "Path to .sim file"
            },
            "solver": {
              "type": "string",
              "description": "Solver type",
              "enum": ["nastran", "NX_Nastran", "abaqus"]
            },
            "solution_type": {
              "type": "string",
              "description": "Solution type (e.g., SOL101)",
              "pattern": "^SOL\\d+$"
            },
            "subcases": {
              "type": "array",
              "description": "Defined subcases",
              "items": {
                "type": "object",
                "properties": {
                  "id": {
                    "type": "integer"
                  },
                  "name": {
                    "type": "string"
                  },
                  "type": {
                    "type": "string",
                    "enum": ["static", "modal", "thermal", "buckling"]
                  }
                }
              }
            }
          }
        },
        "nx_settings": {
          "type": "object",
          "description": "NX runtime settings",
          "properties": {
            "nx_install_path": {
              "type": "string"
            },
            "simulation_timeout_s": {
              "type": "integer",
              "minimum": 60,
              "maximum": 7200
            },
            "auto_start_nx": {
              "type": "boolean"
            }
          }
        }
      }
    },

    "design_variable": {
      "type": "object",
      "description": "A design variable to optimize",
      "required": ["id", "name", "expression_name", "type", "bounds"],
      "properties": {
        "id": {
          "type": "string",
          "description": "Unique identifier",
          "pattern": "^dv_\\d{3}$"
        },
        "name": {
          "type": "string",
          "description": "Human-readable name"
        },
        "expression_name": {
          "type": "string",
          "description": "NX expression name (must match model)",
          "pattern": "^[a-zA-Z_][a-zA-Z0-9_]*$"
        },
        "type": {
          "type": "string",
          "description": "Variable type",
          "enum": ["continuous", "integer", "categorical"]
        },
        "bounds": {
          "type": "object",
          "description": "Value bounds",
          "required": ["min", "max"],
          "properties": {
            "min": {
              "type": "number"
            },
            "max": {
              "type": "number"
            }
          }
        },
        "baseline": {
          "type": "number",
          "description": "Current/initial value"
        },
        "units": {
          "type": "string",
          "description": "Physical units (mm, deg, etc.)"
        },
        "step": {
          "type": "number",
          "description": "Step size for integer/discrete"
        },
        "enabled": {
          "type": "boolean",
          "description": "Whether to include in optimization",
          "default": true
        },
        "description": {
          "type": "string"
        },
        "canvas_position": {
          "$ref": "#/definitions/position"
        }
      }
    },

    "extractor": {
      "type": "object",
      "description": "Physics extractor that computes outputs from FEA",
      "required": ["id", "name", "type", "outputs"],
      "properties": {
        "id": {
          "type": "string",
          "description": "Unique identifier",
          "pattern": "^ext_\\d{3}$"
        },
        "name": {
          "type": "string",
          "description": "Human-readable name"
        },
        "type": {
          "type": "string",
          "description": "Extractor type",
          "enum": [
            "displacement",
            "frequency",
            "stress",
            "mass",
            "mass_expression",
            "zernike_opd",
            "zernike_csv",
            "temperature",
            "custom_function"
          ]
        },
        "builtin": {
          "type": "boolean",
          "description": "Whether this is a built-in extractor",
          "default": true
        },
        "config": {
          "type": "object",
          "description": "Type-specific configuration",
          "properties": {
            "inner_radius_mm": {
              "type": "number"
            },
            "outer_radius_mm": {
              "type": "number"
            },
            "n_modes": {
              "type": "integer"
            },
            "filter_low_orders": {
              "type": "integer"
            },
            "displacement_unit": {
              "type": "string"
            },
            "reference_subcase": {
              "type": "integer"
            },
            "expression_name": {
              "type": "string"
            },
            "mode_number": {
              "type": "integer"
            },
            "element_type": {
              "type": "string"
            },
            "result_type": {
              "type": "string"
            },
            "metric": {
              "type": "string"
            }
          }
        },
        "function": {
          "type": "object",
          "description": "Custom function definition (for custom_function type)",
          "properties": {
            "name": {
              "type": "string",
              "description": "Function name"
            },
            "module": {
              "type": "string",
              "description": "Python module path"
            },
            "signature": {
              "type": "string",
              "description": "Function signature"
            },
            "source_code": {
              "type": "string",
              "description": "Python source code"
            }
          }
        },
        "outputs": {
          "type": "array",
          "description": "Output values this extractor produces",
          "minItems": 1,
          "items": {
            "type": "object",
            "required": ["name"],
            "properties": {
              "name": {
                "type": "string",
                "description": "Output name (used by objectives/constraints)"
              },
              "metric": {
                "type": "string",
                "description": "Specific metric (max, total, rms, etc.)"
              },
              "subcase": {
                "type": "integer",
                "description": "Subcase ID for this output"
              },
              "units": {
                "type": "string"
              }
            }
          }
        },
        "canvas_position": {
          "$ref": "#/definitions/position"
        }
      }
    },

    "objective": {
      "type": "object",
      "description": "Optimization objective",
      "required": ["id", "name", "direction", "source"],
      "properties": {
        "id": {
          "type": "string",
          "description": "Unique identifier",
          "pattern": "^obj_\\d{3}$"
        },
        "name": {
          "type": "string",
          "description": "Human-readable name"
        },
        "direction": {
          "type": "string",
          "description": "Optimization direction",
          "enum": ["minimize", "maximize"]
        },
        "weight": {
          "type": "number",
          "description": "Weight for weighted sum (multi-objective)",
          "minimum": 0,
          "default": 1.0
        },
        "source": {
          "type": "object",
          "description": "Where the value comes from",
          "required": ["extractor_id", "output_name"],
          "properties": {
            "extractor_id": {
              "type": "string",
              "description": "Reference to extractor"
            },
            "output_name": {
              "type": "string",
              "description": "Which output from the extractor"
            }
          }
        },
        "target": {
          "type": "number",
          "description": "Target value (for goal programming)"
        },
        "units": {
          "type": "string"
        },
        "description": {
          "type": "string"
        },
        "canvas_position": {
          "$ref": "#/definitions/position"
        }
      }
    },

    "constraint": {
      "type": "object",
      "description": "Hard or soft constraint",
      "required": ["id", "name", "type", "operator", "threshold", "source"],
      "properties": {
        "id": {
          "type": "string",
          "description": "Unique identifier",
          "pattern": "^con_\\d{3}$"
        },
        "name": {
          "type": "string"
        },
        "type": {
          "type": "string",
          "description": "Constraint type",
          "enum": ["hard", "soft"]
        },
        "operator": {
          "type": "string",
          "description": "Comparison operator",
          "enum": ["<=", ">=", "<", ">", "=="]
        },
        "threshold": {
          "type": "number",
          "description": "Constraint threshold value"
        },
        "source": {
          "type": "object",
          "description": "Where the value comes from",
          "required": ["extractor_id", "output_name"],
          "properties": {
            "extractor_id": {
              "type": "string"
            },
            "output_name": {
              "type": "string"
            }
          }
        },
        "penalty_config": {
          "type": "object",
          "description": "Penalty method configuration",
          "properties": {
            "method": {
              "type": "string",
              "enum": ["linear", "quadratic", "exponential"]
            },
            "weight": {
              "type": "number"
            },
            "margin": {
              "type": "number",
              "description": "Soft margin before penalty kicks in"
            }
          }
        },
        "description": {
          "type": "string"
        },
        "canvas_position": {
          "$ref": "#/definitions/position"
        }
      }
    },

    "optimization": {
      "type": "object",
      "description": "Optimization algorithm configuration",
      "required": ["algorithm", "budget"],
      "properties": {
        "algorithm": {
          "type": "object",
          "required": ["type"],
          "properties": {
            "type": {
              "type": "string",
              "description": "Algorithm type",
              "enum": ["TPE", "CMA-ES", "NSGA-II", "RandomSearch", "SAT_v3", "GP-BO"]
            },
            "config": {
              "type": "object",
              "description": "Algorithm-specific settings",
              "properties": {
                "population_size": {
                  "type": "integer"
                },
                "n_generations": {
                  "type": "integer"
                },
                "mutation_prob": {
                  "type": ["number", "null"]
                },
                "crossover_prob": {
                  "type": "number"
                },
                "seed": {
                  "type": "integer"
                },
                "n_startup_trials": {
                  "type": "integer"
                },
                "sigma0": {
                  "type": "number"
                }
              }
            }
          }
        },
        "budget": {
          "type": "object",
          "description": "Computational budget",
          "properties": {
            "max_trials": {
              "type": "integer",
              "minimum": 1,
              "maximum": 10000
            },
            "max_time_hours": {
              "type": "number"
            },
            "convergence_patience": {
              "type": "integer",
              "description": "Stop if no improvement for N trials"
            }
          }
        },
        "surrogate": {
          "type": "object",
          "description": "Neural surrogate configuration",
          "properties": {
            "enabled": {
              "type": "boolean"
            },
            "type": {
              "type": "string",
              "enum": ["MLP", "GNN", "ensemble"]
            },
            "config": {
              "type": "object",
              "properties": {
                "n_models": {
                  "type": "integer"
                },
                "architecture": {
                  "type": "array",
                  "items": {
                    "type": "integer"
                  }
                },
                "train_every_n_trials": {
                  "type": "integer"
                },
                "min_training_samples": {
                  "type": "integer"
                },
                "acquisition_candidates": {
                  "type": "integer"
                },
                "fea_validations_per_round": {
                  "type": "integer"
                }
              }
            }
          }
        },
        "canvas_position": {
          "$ref": "#/definitions/position"
        }
      }
    },

    "workflow": {
      "type": "object",
      "description": "Multi-stage optimization workflow",
      "properties": {
        "stages": {
          "type": "array",
          "items": {
            "type": "object",
            "properties": {
              "id": {
                "type": "string"
              },
              "name": {
                "type": "string"
              },
              "algorithm": {
                "type": "string"
              },
              "trials": {
                "type": "integer"
              },
              "purpose": {
                "type": "string"
              }
            }
          }
        },
        "transitions": {
          "type": "array",
          "items": {
            "type": "object",
            "properties": {
              "from": {
                "type": "string"
              },
              "to": {
                "type": "string"
              },
              "condition": {
                "type": "string"
              }
            }
          }
        }
      }
    },

    "reporting": {
      "type": "object",
      "description": "Reporting configuration",
      "properties": {
        "auto_report": {
          "type": "boolean"
        },
        "report_triggers": {
          "type": "array",
          "items": {
            "type": "string"
          }
        },
        "insights": {
          "type": "array",
          "items": {
            "type": "object",
            "properties": {
              "type": {
                "type": "string"
              },
              "for_trials": {
                "type": "string"
              },
              "config": {
                "type": "object"
              }
            }
          }
        }
      }
    },

    "canvas": {
      "type": "object",
      "description": "Canvas UI state (persisted for reconstruction)",
      "properties": {
        "layout_version": {
          "type": "string"
        },
        "viewport": {
          "type": "object",
          "properties": {
            "x": {
              "type": "number"
            },
            "y": {
              "type": "number"
            },
            "zoom": {
              "type": "number"
            }
          }
        },
        "edges": {
          "type": "array",
          "description": "Connections between nodes",
          "items": {
            "type": "object",
            "required": ["source", "target"],
            "properties": {
              "source": {
                "type": "string"
              },
              "target": {
                "type": "string"
              },
              "sourceHandle": {
                "type": "string"
              },
              "targetHandle": {
                "type": "string"
              }
            }
          }
        },
        "groups": {
          "type": "array",
          "description": "Node groupings for organization",
          "items": {
            "type": "object",
            "properties": {
              "id": {
                "type": "string"
              },
              "name": {
                "type": "string"
              },
              "node_ids": {
                "type": "array",
                "items": {
                  "type": "string"
                }
              }
            }
          }
        }
      }
    },

    "position": {
      "type": "object",
      "description": "Canvas position",
      "properties": {
        "x": {
          "type": "number"
        },
        "y": {
          "type": "number"
        }
      }
    }
  }
}