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import type { ExecutionContext } from './types.ts'import type { Environment, NotFoundHandler, ContextVariableMap } from './types.ts'import type { CookieOptions } from './utils/cookie.ts'import { serialize } from './utils/cookie.ts'import type { StatusCode } from './utils/http-status.ts'import type { Schema, SchemaToProp } from './validator/schema.ts'
type HeaderField = [string, string]type Headers = Record<string, string | string[]>type Runtime = 'node' | 'deno' | 'bun' | 'cloudflare' | 'fastly' | 'vercel' | 'lagon' | 'other'export type Data = string | ArrayBuffer | ReadableStream
export class Context<  P extends string = string,  E extends Partial<Environment> = Environment,  // eslint-disable-next-line @typescript-eslint/no-explicit-any  S = any> {  req: Request<unknown, P, S extends Schema ? SchemaToProp<S> : S>  env: E['Bindings']  finalized: boolean  error: Error | undefined = undefined
  private _status: StatusCode = 200  private _executionCtx: FetchEvent | ExecutionContext | undefined  private _pretty: boolean = false  private _prettySpace: number = 2  private _map: Record<string, unknown> | undefined  private _headers: Record<string, string[]> | undefined  private _res: Response | undefined  private notFoundHandler: NotFoundHandler<E>
  constructor(    req: Request<unknown, P>,    env: E['Bindings'] = {},    executionCtx: FetchEvent | ExecutionContext | undefined = undefined,    notFoundHandler: NotFoundHandler<E> = () => new Response()  ) {    this._executionCtx = executionCtx    this.req = req as Request<unknown, P>    this.env = env
    this.notFoundHandler = notFoundHandler    this.finalized = false  }
  get event(): FetchEvent {    if (this._executionCtx instanceof FetchEvent) {      return this._executionCtx    } else {      throw Error('This context has no FetchEvent')    }  }
  get executionCtx(): ExecutionContext {    if (this._executionCtx) {      return this._executionCtx as ExecutionContext    } else {      throw Error('This context has no ExecutionContext')    }  }
  get res(): Response {    return (this._res ||= new Response('404 Not Found', { status: 404 }))  }
  set res(_res: Response) {    this._res = _res    this.finalized = true  }
  header(name: string, value: string, options?: { append?: boolean }): void {    this._headers ||= {}    const key = name.toLowerCase()
    let shouldAppend = false    if (options && options.append) {      const vAlreadySet = this._headers[key]      if (vAlreadySet && vAlreadySet.length) {        shouldAppend = true      }    }
    if (shouldAppend) {      this._headers[key].push(value)    } else {      this._headers[key] = [value]    }
    if (this.finalized) {      if (shouldAppend) {        this.res.headers.append(name, value)      } else {        this.res.headers.set(name, value)      }    }  }
  status(status: StatusCode): void {    this._status = status  }
  set<Key extends keyof ContextVariableMap>(key: Key, value: ContextVariableMap[Key]): void  set<Key extends keyof E['Variables']>(key: Key, value: E['Variables'][Key]): void  set(key: string, value: unknown): void  set(key: string, value: unknown): void {    this._map ||= {}    this._map[key] = value  }
  get<Key extends keyof ContextVariableMap>(key: Key): ContextVariableMap[Key]  get<Key extends keyof E['Variables']>(key: Key): E['Variables'][Key]  get<T>(key: string): T  get(key: string) {    if (!this._map) {      return undefined    }    return this._map[key]  }
  pretty(prettyJSON: boolean, space: number = 2): void {    this._pretty = prettyJSON    this._prettySpace = space  }
  newResponse(data: Data | null, status: StatusCode, headers: Headers = {}): Response {    return new Response(data, {      status,      headers: this._finalizeHeaders(headers),    })  }
  private _finalizeHeaders(incomingHeaders: Headers): HeaderField[] {    const finalizedHeaders: HeaderField[] = []    const headersKv = this._headers || {}    // If Response is already set    if (this._res) {      this._res.headers.forEach((v, k) => {        headersKv[k] = [v]      })    }    for (const key of Object.keys(incomingHeaders)) {      const value = incomingHeaders[key]      if (typeof value === 'string') {        finalizedHeaders.push([key, value])      } else {        for (const v of value) {          finalizedHeaders.push([key, v])        }      }      delete headersKv[key]    }    for (const key of Object.keys(headersKv)) {      for (const value of headersKv[key]) {        const kv: HeaderField = [key, value]        finalizedHeaders.push(kv)      }    }    return finalizedHeaders  }
  body(data: Data | null, status: StatusCode = this._status, headers: Headers = {}): Response {    return this.newResponse(data, status, headers)  }
  text(text: string, status?: StatusCode, headers?: Headers): Response {    // If the header is empty, return Response immediately.    // Content-Type will be added automatically as `text/plain`.    if (!headers && !status && !this._res && !this._headers) {      return new Response(text)    }    status ||= this._status    headers ||= {}    headers['content-type'] = 'text/plain; charset=UTF-8'    return this.newResponse(text, status, headers)  }
  json<T>(object: T, status: StatusCode = this._status, headers: Headers = {}): Response {    const body = this._pretty      ? JSON.stringify(object, null, this._prettySpace)      : JSON.stringify(object)    headers['content-type'] = 'application/json; charset=UTF-8'    return this.newResponse(body, status, headers)  }
  html(html: string, status: StatusCode = this._status, headers: Headers = {}): Response {    headers['content-type'] = 'text/html; charset=UTF-8'    return this.newResponse(html, status, headers)  }
  redirect(location: string, status: StatusCode = 302): Response {    return this.newResponse(null, status, {      Location: location,    })  }
  cookie(name: string, value: string, opt?: CookieOptions): void {    const cookie = serialize(name, value, opt)    this.header('set-cookie', cookie, { append: true })  }
  notFound(): Response | Promise<Response> {    return this.notFoundHandler(this as unknown as Context<string, E>)  }
  get runtime(): Runtime {    // eslint-disable-next-line @typescript-eslint/no-explicit-any    const global = globalThis as any
    if (global?.Deno !== undefined) {      return 'deno'    }
    if (global?.Bun !== undefined) {      return 'bun'    }
    if (typeof global?.WebSocketPair === 'function') {      return 'cloudflare'    }
    if (global?.fastly !== undefined) {      return 'fastly'    }
    if (typeof global?.EdgeRuntime === 'string') {      return 'vercel'    }
    if (global?.process?.release?.name === 'node') {      return 'node'    }
    if (global?.__lagon__ !== undefined) {      return 'lagon'    }
    return 'other'  }}