import {z} from 'zod'

export type ChatMessage = {role: string, content?: (string | Array<{[key: string]: unknown}> | null) | undefined, name?: (string | null) | undefined, tool_calls?: (Array<unknown> | null) | undefined, tool_call_id?: (string | null) | undefined, reasoning_content?: (string | null) | undefined};

export type ChatCompletionRequest = {model: string, messages: Array<ChatMessage>, system?: (string | Array<{[key: string]: unknown}> | null) | undefined, temperature?: (number | null) | undefined, max_tokens?: (number | null) | undefined, response_format?: ({[key: string]: unknown} | null) | undefined, stop?: (Array<string> | string | null) | undefined, stream?: boolean | undefined, extra_headers?: ({[key: string]: string} | null) | undefined, extra_body?: ({[key: string]: unknown} | null) | undefined, reasoning?: ({[key: string]: unknown} | null) | undefined, store?: boolean | undefined, metadata?: ({[key: string]: unknown} | null) | undefined, top_p?: (number | null) | undefined, n?: (number | null) | undefined, presence_penalty?: (number | null) | undefined, frequency_penalty?: (number | null) | undefined, logit_bias?: ({[key: string]: unknown} | null) | undefined, user?: (string | null) | undefined, seed?: (number | null) | undefined, tools?: (Array<unknown> | null) | undefined, tool_choice?: (string | {[key: string]: unknown} | null) | undefined, schema?: (Array<string> | {[key: string]: unknown} | null) | undefined, task_type?: (string | null) | undefined, include_confidence?: boolean | undefined, include_spans?: boolean | undefined, threshold?: number | undefined};

export type CreateApiV1ChatCompletionsArgs = {body: ChatCompletionRequest};

export type CreateApiV1ChatCompletionsOptions = {baseUrl: string, ApiKeyAuth?: string | undefined, fetch?: typeof fetch | undefined};

export const chatCompletionChoice = z.object({index: z.number().int().optional(), message: z.record(z.string(), z.unknown()).optional(), finish_reason: z.string().nullable().optional()});

export const promptTokensDetails = z.object({cached_tokens: z.number().int().optional(), cache_write_tokens: z.number().int().optional()});

export const chatCompletionUsage = z.object({prompt_tokens: z.number().int().optional(), completion_tokens: z.number().int().optional(), total_tokens: z.number().int().optional(), prompt_tokens_details: promptTokensDetails.nullable().optional()});

export const fastinoExtension = z.object({inference_id: z.string().nullable().optional()});

export const chatCompletionResponse = z.object({id: z.string().optional(), object: z.string().optional(), created: z.number().int().optional(), model: z.string(), choices: z.array(chatCompletionChoice), usage: chatCompletionUsage, x_fastino: fastinoExtension.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
};

/**
 * Chat Completions
 * 
 * POST /v1/chat/completions
 * 
 * Also accepts auth: BearerAuth
 */
export const createApiV1ChatCompletions = async (args: CreateApiV1ChatCompletionsArgs, options: CreateApiV1ChatCompletionsOptions) => {
const {baseUrl, fetch: fetchFn = fetch, ApiKeyAuth} = options ?? {}

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

if (ApiKeyAuth !== undefined) headers.set("X-API-Key", ApiKeyAuth)

const url = `${baseUrl.replace(/\/+$/, '')}/v1/chat/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(chatCompletionResponse, await res.json())
};