import {z} from 'zod'

export type FunctionCall = {name: string, arguments: string};

export type ChatCompletionMessageToolCall = {id: string, type: 'function', function: FunctionCall};

export type ChatCompletionRequestMessage = {role: 'assistant', content?: (string | null) | undefined, tool_calls?: (Array<ChatCompletionMessageToolCall> | null) | undefined} | {role: 'system', content: string} | {role: 'tool', content: string, tool_call_id: string} | {role: 'user', content: string};

export type SarvamModelIds = 'sarvam-105b' | 'sarvam-30b';

export type ReasoningEffort = 'low' | 'medium' | 'high';

export type StopConfiguration = string | Array<string>;

export type FunctionDefinition = {name: string, description?: (string | null) | undefined, parameters?: ({[key: string]: unknown} | null) | undefined};

export type ChatCompletionTool = {type: 'function', function: FunctionDefinition};

export type ToolChoiceOption0 = 'none' | 'auto' | 'required';

export type ChatCompletionNamedToolChoiceFunction = {name: string};

export type ChatCompletionNamedToolChoice = {type: 'function', function: ChatCompletionNamedToolChoiceFunction};

export type ToolChoiceOption = ToolChoiceOption0 | ChatCompletionNamedToolChoice;

export type JsonSchemaDefinitionSchema = Record<string, never>;

export type JsonSchemaDefinition = {name: string, description?: (string | null) | undefined, schema?: (JsonSchemaDefinitionSchema | null) | undefined, strict?: (boolean | null) | undefined};

export type ResponseFormat = {type: 'text'} | {type: 'json_object'} | {type: 'json_schema', json_schema: JsonSchemaDefinition};

export type CreateChatCompletionRequest = {messages: Array<ChatCompletionRequestMessage>, model: SarvamModelIds, temperature?: (number | null) | undefined, top_p?: (number | null) | undefined, reasoning_effort?: (ReasoningEffort | null) | undefined, max_tokens?: (number | null) | undefined, stream?: (boolean | null) | undefined, stop?: (StopConfiguration | null) | undefined, n?: (number | null) | undefined, seed?: (number | null) | undefined, frequency_penalty?: (number | null) | undefined, presence_penalty?: (number | null) | undefined, wiki_grounding?: (boolean | null) | undefined, tools?: (Array<ChatCompletionTool> | null) | undefined, tool_choice?: (ToolChoiceOption | null) | undefined, response_format?: (ResponseFormat | null) | undefined};

export type CreateApiV1ChatCompletionsArgs = {Authorization: string, 'api-subscription-key'?: (string | null) | undefined, body: CreateChatCompletionRequest};

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

export const finishReason = z.enum(["stop", "length", "tool_calls", "content_filter", "function_call"]);

export const role = z.literal("assistant");

export const functionCall = z.object({name: z.string(), arguments: z.string()});

export const chatCompletionMessageToolCall = z.object({id: z.string(), type: z.literal("function"), function: functionCall});

export const chatCompletionResponseMessage = z.object({content: z.string().nullable(), refusal: z.string().nullable().optional(), reasoning_content: z.string().nullable().optional(), role: role, tool_calls: z.array(chatCompletionMessageToolCall).nullable().optional()});

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

export const completionUsage = z.object({completion_tokens: z.number().int(), prompt_tokens: z.number().int(), total_tokens: z.number().int(), completion_tokens_details: z.record(z.string(), z.unknown()).nullable().optional(), prompt_tokens_details: z.record(z.string(), z.unknown()).nullable().optional()});

export const createChatCompletionResponse = z.object({id: z.string(), choices: z.array(choice), created: z.number().int(), model: z.string(), object: z.literal("chat.completion"), service_tier: z.string().nullable().optional(), system_fingerprint: z.string().nullable().optional(), usage: completionUsage.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
 */
export const createApiV1ChatCompletions = async (args: CreateApiV1ChatCompletionsArgs, options?: CreateApiV1ChatCompletionsOptions) => {
const {baseUrl = "https://api.sarvam.ai", fetch: fetchFn = fetch} = options ?? {}

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

if (args.Authorization != null) headers.set("Authorization", String(args.Authorization))
if (args['api-subscription-key'] != null) headers.set("api-subscription-key", String(args['api-subscription-key']))

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(createChatCompletionResponse, await res.json())
};