import {z} from 'zod'

export type AICompletionMetadataResource = {transactionId: string, traceId?: string | undefined, model: string, responseQualityScore?: number | undefined, modelSource?: string | undefined, inputTokenCount: number, outputTokenCount: number, reasoningTokenCount?: number | undefined, cacheCreationTokenCount?: number | undefined, cacheReadTokenCount?: number | undefined, totalTokenCount: number, stopReason: 'END' | 'END_SEQUENCE' | 'TIMEOUT' | 'TOKEN_LIMIT' | 'COST_LIMIT' | 'COMPLETION_LIMIT' | 'ERROR', inputTokenCost?: number | undefined, outputTokenCost?: number | undefined, totalCost?: number | undefined, costType: 'AI', requestTime: string, completionStartTime: string, timeToFirstToken?: number | undefined, isStreamed: boolean, responseTime: string, requestDuration: number, mediationLatency?: number | undefined, provider: string, taskType?: string | undefined, subscriberCredentialName?: string | undefined, subscriberCredential?: string | undefined, subscriberEmail?: string | undefined, subscriberId?: string | undefined, organizationId?: string | undefined, subscriptionId?: string | undefined, productId?: string | undefined, agent?: string | undefined, operationType?: ('CHAT' | 'GENERATE' | 'EMBED' | 'CLASSIFY' | 'SUMMARIZE' | 'TRANSLATE' | 'OTHER') | undefined, systemFingerprint?: string | undefined, temperature?: number | undefined, errorReason?: string | undefined};

export type CreateApiV2AiCompletionsArgs = {body: AICompletionMetadataResource};

export type CreateApiV2AiCompletionsOptions = {baseUrl?: string | undefined, xApiKey?: string | undefined, fetch?: typeof fetch | undefined};

export const link = z.object({href: z.string().optional(), hreflang: z.string().optional(), title: z.string().optional(), type: z.string().optional(), deprecation: z.string().optional(), profile: z.string().optional(), name: z.string().optional(), templated: z.boolean().optional()});

export const links = z.record(z.string(), link);

export const meteringResponseResource = z.object({object: z.string(), label: z.string(), created: z.string().optional(), updated: z.string().optional(), id: z.string(), signature: z.string(), _links: links.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
};

/**
 * Meter an LLM completion
 * 
 * POST /v2/ai/completions
 */
export const createApiV2AiCompletions = async (args: CreateApiV2AiCompletionsArgs, options?: CreateApiV2AiCompletionsOptions) => {
const {baseUrl = "https://api.revenium.io/meter", fetch: fetchFn = fetch, xApiKey} = options ?? {}

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

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

const url = `${baseUrl.replace(/\/+$/, '')}/v2/ai/completions${query.size > 0 ? `?${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(meteringResponseResource, await res.json())
};