import {z} from 'zod'

export type MessageInput = {role: 'system' | 'user' | 'assistant', content: string};

export type InvokeRequest = {messages: Array<MessageInput>, router_config_id?: (string | null) | undefined, config_overrides?: ({[key: string]: unknown} | null) | undefined, session_id?: (string | null) | undefined, smart_routing?: boolean | undefined};

export type CreateApiV1ModelRouterInvokeArgs = {body: InvokeRequest};

export type CreateApiV1ModelRouterInvokeOptions = {baseUrl: string, APIKeyHeader?: string | undefined, fetch?: typeof fetch | undefined};

export const modelTier = z.enum(["economy", "standard", "premium"]);

export const smartRoutingMetadata = z.object({classifier_model: z.string(), classifier_tier: modelTier, classifier_confidence: z.number(), recommended_model: z.string(), executed_model: z.string(), candidate_chain: z.array(z.string()), reason: z.string()});

export const modelResponse = z.object({content: z.string(), model_identifier: z.string(), provider: z.string(), input_tokens: z.number().int(), output_tokens: z.number().int(), total_tokens: z.number().int(), input_cost_usd: z.number(), output_cost_usd: z.number(), cache_cost_usd: z.number().optional(), total_cost_usd: z.number(), latency_ms: z.number().int(), routing_metadata: smartRoutingMetadata.nullable().optional(), parsed_output: z.record(z.string(), z.unknown()).nullable().optional(), execution_engine: z.enum(["pydantic_text", "pydantic_structured"]).optional(), cache_read_input_tokens: z.number().int().optional(), cache_creation_input_tokens: z.number().int().optional(), cache_hit: z.boolean().optional(), route_decision_id: 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
};

/**
 * Invoke a model with routing
 * 
 * POST /v1/model-router/invoke
 */
export const createApiV1ModelRouterInvoke = async (args: CreateApiV1ModelRouterInvokeArgs, options: CreateApiV1ModelRouterInvokeOptions) => {
const {baseUrl, fetch: fetchFn = fetch, APIKeyHeader} = options ?? {}

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

if (APIKeyHeader !== undefined) headers.set("x-api-key", APIKeyHeader)

const url = `${baseUrl.replace(/\/+$/, '')}/v1/model-router/invoke${query.size > 0 ? `?${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(modelResponse, await res.json())
};