/** DSH Tool Schema to deterministic retrieval document projection. @module dsh-tool-retriever/retrieval/document */

import { normalizeIdentifier, tokenize } from './tokenizer.ts'
import type { ToolDocument } from './types.ts'

/** Minimal schema projection supplied by `ctx.tools.schemas()`. */
export interface CatalogToolSchema {
  name: string
  description: string
  parameters: Record<string, unknown>
}

/**
 * Build a searchable document without generated aliases or inferred capabilities.
 * @param schema - Model-facing schema read from the live DSH tool registry.
 * @returns Tokenized deterministic fields used by Exact and BM25F retrieval.
 */
export function buildToolDocument(schema: CatalogToolSchema): ToolDocument {
  const parameterNames: string[] = []
  const parameterDescriptions: string[] = []
  collectSchemaText(schema.parameters, parameterNames, parameterDescriptions)
  return {
    name: schema.name,
    normalizedName: normalizeIdentifier(schema.name),
    description: schema.description,
    fields: {
      name: tokenize(schema.name),
      description: tokenize(schema.description),
      parameterName: parameterNames.flatMap(tokenize),
      parameterDescription: parameterDescriptions.flatMap(tokenize),
    },
  }
}

/** Recursively collect only text that is explicitly present in the input schema. */
function collectSchemaText(value: unknown, names: string[], descriptions: string[]): void {
  if (Array.isArray(value)) {
    for (const item of value) collectSchemaText(item, names, descriptions)
    return
  }
  if (value === null || typeof value !== 'object') return
  for (const [key, child] of Object.entries(value)) {
    if (key === 'properties' && child !== null && typeof child === 'object' && !Array.isArray(child)) {
      for (const [propertyName, propertySchema] of Object.entries(child)) {
        names.push(propertyName)
        collectSchemaText(propertySchema, names, descriptions)
      }
      continue
    }
    if ((key === 'description' || key === 'title') && typeof child === 'string') {
      descriptions.push(child)
      continue
    }
    if (key === 'enum' && Array.isArray(child)) {
      for (const literal of child) {
        if (typeof literal === 'string' || typeof literal === 'number') descriptions.push(String(literal))
      }
      continue
    }
    collectSchemaText(child, names, descriptions)
  }
}