import {z} from 'zod'

export type GetApiV2MessagesArgs = {limit?: number | undefined, cursor?: (string | null) | undefined, direction?: ('older' | 'newer') | undefined, parent_tool_use_id?: (string | null) | undefined, task_id: string};

export type GetApiV2MessagesOptions = {baseUrl: string, fetch?: typeof fetch | undefined};

export const usage = z.object({inputTokens: z.number().int(), outputTokens: z.number().int(), totalTokens: z.number().int().nullable().optional()});

export const uIMessageMetadata = z.object({costUsd: z.number().nullable().optional(), durationMs: z.number().int().nullable().optional(), model: z.string().nullable().optional(), parentToolUseId: z.string().nullable().optional(), usage: usage.nullable().optional()});

export const textPart = z.object({text: z.string(), type: z.literal("text").optional()});

export const reasoningPart = z.object({providerMetadata: z.record(z.string(), z.unknown()).nullable().optional(), text: z.string(), type: z.literal("reasoning").optional()});

export const toolPartState = z.enum(["input-streaming", "input-available", "output-available", "output-error"]);

export const toolPart = z.object({errorText: z.string().nullable().optional(), input: z.record(z.string(), z.unknown()), output: z.unknown(), state: toolPartState, toolCallId: z.string(), toolName: z.string(), type: z.literal("tool").optional()});

export const sourceUrlPart = z.object({sourceId: z.string(), title: z.string().nullable().optional(), type: z.literal("source-url").optional(), url: z.string()});

export const filePart = z.object({mediaType: z.string(), type: z.literal("file").optional(), url: z.string()});

export const dataPart = z.object({data: z.unknown(), type: z.literal("data").optional()});

export const errorPart = z.object({error: z.string(), rawContent: z.unknown(), type: z.literal("error").optional()});

export const uIMessagePartWrapper = z.discriminatedUnion("type", [textPart, reasoningPart, toolPart, sourceUrlPart, filePart, dataPart, errorPart]);

export const uIMessageRole = z.enum(["system", "user", "assistant"]);

export const uIMessage = z.object({createdAt: z.string().nullable().optional(), id: z.string(), metadata: uIMessageMetadata.nullable().optional(), parts: z.array(uIMessagePartWrapper), role: uIMessageRole});

export const listMessagesV2Response = z.object({data: z.array(uIMessage), hasMore: z.boolean().optional(), nextCursor: 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
};

/**
 * List Messages (v2 - UIMessage format)
 * 
 * GET /v2/messages
 */
export const getApiV2Messages = async (args: GetApiV2MessagesArgs, options: GetApiV2MessagesOptions) => {
const {baseUrl, fetch: fetchFn = fetch} = options ?? {}

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

if (args.limit != null) query.append("limit", String(args.limit))
if (args.cursor != null) query.append("cursor", String(args.cursor))
if (args.direction != null) query.append("direction", String(args.direction))
if (args.parent_tool_use_id != null) query.append("parent_tool_use_id", String(args.parent_tool_use_id))
if (args.task_id != null) query.append("task_id", String(args.task_id))

const url = `${baseUrl.replace(/\/+$/, '')}/v2/messages${query.size > 0 ? `?${query}` : ''}`

const res = await fetchFn(url, {method: "GET", headers})

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

return validateResponse(listMessagesV2Response, await res.json())
};