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import type { Context } from '../context.ts'import { getCookie } from '../helper/cookie/index.ts'import { HTTPException } from '../http-exception.ts'import type { Env, ValidationTargets, MiddlewareHandler, TypedResponse } from '../types.ts'import type { BodyData } from '../utils/body.ts'import { bufferToFormData } from '../utils/buffer.ts'
type ValidationTargetKeysWithBody = 'form' | 'json'type ValidationTargetByMethod<M> = M extends 'get' | 'head' // GET and HEAD request must not have a body content.  ? Exclude<keyof ValidationTargets, ValidationTargetKeysWithBody>  : keyof ValidationTargets
export type ValidationFunction<  InputType,  OutputType,  E extends Env = {},  P extends string = string> = (  value: InputType,  c: Context<E, P>) => OutputType | Response | Promise<OutputType> | Promise<Response>
// eslint-disable-next-line @typescript-eslint/no-explicit-anytype ExcludeResponseType<T> = T extends Response & TypedResponse<any> ? never : T
export const validator = <  InputType,  P extends string,  M extends string,  U extends ValidationTargetByMethod<M>,  OutputType = ValidationTargets[U],  OutputTypeExcludeResponseType = ExcludeResponseType<OutputType>,  P2 extends string = P,  V extends {    in: {      [K in U]: K extends 'json'        ? unknown extends InputType          ? OutputTypeExcludeResponseType          : InputType        : { [K2 in keyof OutputTypeExcludeResponseType]: ValidationTargets[K][K2] }    }    out: { [K in U]: OutputTypeExcludeResponseType }  } = {    in: {      [K in U]: K extends 'json'        ? unknown extends InputType          ? OutputTypeExcludeResponseType          : InputType        : { [K2 in keyof OutputTypeExcludeResponseType]: ValidationTargets[K][K2] }    }    out: { [K in U]: OutputTypeExcludeResponseType }  },  // eslint-disable-next-line @typescript-eslint/no-explicit-any  E extends Env = any>(  target: U,  validationFunc: ValidationFunction<    unknown extends InputType ? ValidationTargets[U] : InputType,    OutputType,    E,    P2  >): MiddlewareHandler<E, P, V> => {  return async (c, next) => {    let value = {}    const contentType = c.req.header('Content-Type')
    switch (target) {      case 'json':        if (!contentType || !contentType.startsWith('application/json')) {          const message = `Invalid HTTP header: Content-Type=${contentType}`          throw new HTTPException(400, { message })        }        try {          value = await c.req.json()        } catch {          const message = 'Malformed JSON in request body'          throw new HTTPException(400, { message })        }        break      case 'form': {        if (!contentType) {          break        }
        if (c.req.bodyCache.formData) {          value = await c.req.bodyCache.formData          break        }
        try {          const arrayBuffer = await c.req.arrayBuffer()          const formData = await bufferToFormData(arrayBuffer, contentType)          const form: BodyData = {}          formData.forEach((value, key) => {            form[key] = value          })          value = form          c.req.bodyCache.formData = formData        } catch (e) {          let message = 'Malformed FormData request.'          message += e instanceof Error ? ` ${e.message}` : ` ${String(e)}`          throw new HTTPException(400, { message })        }        break      }      case 'query':        value = Object.fromEntries(          Object.entries(c.req.queries()).map(([k, v]) => {            return v.length === 1 ? [k, v[0]] : [k, v]          })        )        break      case 'param':        value = c.req.param() as Record<string, string>        break      case 'header':        value = c.req.header()        break      case 'cookie':        value = getCookie(c)        break    }
    const res = await validationFunc(value as never, c as never)
    if (res instanceof Response) {      return res    }
    c.req.addValidatedData(target, res as never)
    await next()  }}