import {z} from 'zod'

export type SchemaNode = {fields: Array<string>, vector_fields?: Array<string> | undefined};

export type SchemaEdge = {from: string, to: string};

export type PlannerSchema = {nodes: {[key: string]: SchemaNode}, edges: {[key: string]: SchemaEdge}};

export type QueryPlanRequest = {query: string, schema: PlannerSchema, enable_pruning?: boolean | undefined, use_local_intelligence?: boolean | undefined};

export type CreateApiPlannerPlanArgs = {body: QueryPlanRequest};

export type CreateApiPlannerPlanOptions = {baseUrl: string, HTTPBearer?: string | undefined, fetch?: typeof fetch | undefined};

export const queryPlanResponse = z.object({query_plan: z.object({}), query_type: z.string(), constraint_embeddings: z.record(z.string(), z.array(z.number())).nullable().optional(), complexity_hints: z.object({}).nullable().optional(), latency_ms: z.number(), helix_ql: z.string().nullable().optional(), entity: z.object({}).nullable().optional(), planner_version: z.string().nullable().optional()});

export const validateResponse = async <Output>(
  schema: {
    readonly '~standard': {
      readonly validate: (value: unknown) => ({ readonly value: Output; readonly issues?: undefined } | { readonly issues: ReadonlyArray<{ readonly message: string; readonly path?: ReadonlyArray<PropertyKey | { readonly key: PropertyKey }> | undefined }> }) | Promise<{ readonly value: Output; readonly issues?: undefined } | { readonly issues: ReadonlyArray<{ readonly message: string; readonly path?: ReadonlyArray<PropertyKey | { readonly key: PropertyKey }> | undefined }> }>
    }
  },
  value: unknown
): Promise<Output> => {
  const result = await schema['~standard'].validate(value)

  if (result.issues !== undefined) {
    const detail = result.issues
      .map(({ message, path }) =>
        path?.length
          ? `${path.map((segment) => String(typeof segment === 'object' ? segment.key : segment)).join('.')}: ${message}`
          : message
      )
      .join('; ')

    throw new Error(`Response does not match the schema: ${detail}`, { cause: { issues: result.issues } })
  }

  return result.value
};

/**
 * Generate Query Plan
 * 
 * POST /planner/plan
 */
export const createApiPlannerPlan = async (args: CreateApiPlannerPlanArgs, options: CreateApiPlannerPlanOptions) => {
const {baseUrl, fetch: fetchFn = fetch, HTTPBearer} = options ?? {}

const query = new URLSearchParams()
const headers = new Headers()
headers.set('content-type', "application/json")
headers.set('accept', "application/json")

if (HTTPBearer !== undefined) headers.set('authorization', `Bearer ${HTTPBearer}`)

const url = `${baseUrl.replace(/\/+$/, '')}/planner/plan${query.size > 0 ? `?${query}` : ''}`

const res = await fetchFn(url, {method: "POST", headers, body: JSON.stringify(args.body)})

if (!res.ok) throw new Error(`Request failed with status ${res.status}`, {cause: {status: res.status, body: await res.text()}})

return validateResponse(queryPlanResponse, await res.json())
};