// ModelLedgerEntry — aggregate per-task-type-per-model performance.
// Built by aggregating mode_experiments.jsonl + model_trust.jsonl.
// Updated rather than appended — one row per (model_name, task_type)
// representing latest aggregates.
import {
  ValidationResult, requireString, requireNumber, requireIsoTimestamp, requireStringArray,
} from "./types";

export const MODEL_LEDGER_SCHEMA_VERSION = 1;

export interface ModelLedgerEntry {
  schema_version: number;
  model_name: string;
  model_provider: string;
  task_type: string;
  success_rate: number;          // [0, 1]
  failure_modes: string[];       // top failure mode tags
  best_partner_model?: string;   // pairs well with X (consensus / tie-break)
  escalation_role?: string;      // when this model gets escalated TO (or FROM)
  cost_usd_p50?: number;
  latency_ms_p50?: number;
  latency_ms_p95?: number;
  context_window?: number;
  sample_count: number;
  last_updated: string;          // ISO 8601
  notes?: string;
}

export function validateModelLedgerEntry(input: unknown): ValidationResult<ModelLedgerEntry> {
  const errors: string[] = [];
  if (typeof input !== "object" || input === null) return { valid: false, errors: ["expected object"] };
  const r = input as Record<string, unknown>;
  let ok = true;

  if (r.schema_version !== MODEL_LEDGER_SCHEMA_VERSION) {
    errors.push(`schema_version: expected ${MODEL_LEDGER_SCHEMA_VERSION}, got ${JSON.stringify(r.schema_version)}`);
    ok = false;
  }
  ok = requireString(r.model_name, "model_name", errors) && ok;
  ok = requireString(r.model_provider, "model_provider", errors) && ok;
  ok = requireString(r.task_type, "task_type", errors) && ok;
  ok = requireIsoTimestamp(r.last_updated, "last_updated", errors) && ok;
  ok = requireStringArray(r.failure_modes, "failure_modes", errors) && ok;

  if (!requireNumber(r.success_rate, "success_rate", errors)) ok = false;
  else if ((r.success_rate as number) < 0 || (r.success_rate as number) > 1) {
    errors.push("success_rate: must be in [0, 1]"); ok = false;
  }
  if (!requireNumber(r.sample_count, "sample_count", errors)) ok = false;
  else if ((r.sample_count as number) < 1 || !Number.isInteger(r.sample_count)) {
    errors.push("sample_count: must be positive integer (no aggregate from zero samples)"); ok = false;
  }

  if (!ok) return { valid: false, errors };
  return { valid: true, value: r as unknown as ModelLedgerEntry };
}