import { type HeaderValue } from './header-value.ts'
import { parseParams, quote } from './param-values.ts'
import { capitalize, isValidDate } from './utils.ts'

type SameSiteValue = 'Strict' | 'Lax' | 'None'

/**
 * Properties for a `Set-Cookie` header value.
 */
export interface CookieProperties {
  /**
   * The domain of the cookie. For example, `example.com`.
   *
   * [MDN Reference](https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Set-Cookie#domaindomain-value)
   */
  domain?: string
  /**
   * The expiration date of the cookie. If not specified, the cookie is a session cookie that is
   * removed when the browser is closed.
   *
   * [MDN Reference](https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Set-Cookie#expiresdate)
   */
  expires?: Date
  /**
   * Indicates this cookie should not be accessible via JavaScript.
   *
   * [MDN Reference](https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Set-Cookie#httponly)
   */
  httpOnly?: boolean
  /**
   * The maximum age of the cookie in seconds.
   *
   * [MDN Reference](https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Set-Cookie#max-age)
   */
  maxAge?: number
  /**
   * Indicates this cookie is a partitioned cookie.
   *
   * [MDN Reference](https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Set-Cookie#partitioned)
   */
  partitioned?: boolean
  /**
   * The path of the cookie. For example, `/` or `/admin`.
   *
   * [MDN Reference](https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Set-Cookie#pathpath-value)
   */
  path?: string
  /**
   * The `SameSite` attribute of the cookie. This attribute lets servers require that a cookie shouldn't be sent with
   * cross-site requests, which provides some protection against cross-site request forgery attacks.
   *
   * [MDN Reference](https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Set-Cookie#samesitesamesite-value)
   */
  sameSite?: SameSiteValue
  /**
   * Indicates the cookie should only be sent over HTTPS.
   *
   * [MDN Reference](https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Set-Cookie#secure)
   */
  secure?: boolean
}

/**
 * Initializer for a `Set-Cookie` header value.
 */
export interface SetCookieInit extends CookieProperties {
  /**
   * The name of the cookie.
   *
   * [MDN Reference](https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Set-Cookie#cookie-namecookie-value)
   */
  name?: string
  /**
   * The value of the cookie.
   *
   * [MDN Reference](https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Set-Cookie#cookie-namecookie-value)
   */
  value?: string
}

/**
 * The value of a `Set-Cookie` HTTP header.
 *
 * [MDN `Set-Cookie` Reference](https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Set-Cookie)
 *
 * [HTTP/1.1 Specification](https://datatracker.ietf.org/doc/html/rfc6265#section-4.1)
 */
export class SetCookie implements HeaderValue, SetCookieInit {
  domain?: string
  expires?: Date
  httpOnly?: boolean
  maxAge?: number
  name?: string
  partitioned?: boolean
  path?: string
  sameSite?: SameSiteValue
  secure?: boolean
  value?: string

  constructor(init?: string | SetCookieInit) {
    if (init) return SetCookie.from(init)
  }

  /**
   * Returns the string representation of the header value.
   *
   * @returns The header value as a string
   */
  toString(): string {
    if (!this.name) {
      return ''
    }

    let parts = [`${this.name}=${quote(this.value || '')}`]

    if (this.domain) {
      parts.push(`Domain=${this.domain}`)
    }
    if (this.expires) {
      parts.push(`Expires=${this.expires.toUTCString()}`)
    }
    if (this.httpOnly) {
      parts.push('HttpOnly')
    }
    if (this.maxAge != null) {
      parts.push(`Max-Age=${this.maxAge}`)
    }
    if (this.partitioned) {
      parts.push('Partitioned')
    }
    if (this.path) {
      parts.push(`Path=${this.path}`)
    }
    if (this.sameSite) {
      parts.push(`SameSite=${this.sameSite}`)
    }
    if (this.secure) {
      parts.push('Secure')
    }

    return parts.join('; ')
  }

  /**
   * Parse a Set-Cookie header value.
   *
   * @param value The header value (string, init object, or null)
   * @returns A SetCookie instance (empty if null)
   */
  static from(value: string | SetCookieInit | null): SetCookie {
    let header = new SetCookie()

    if (value !== null) {
      if (typeof value === 'string') {
        let params = parseParams(value)
        if (params.length > 0) {
          header.name = params[0][0]
          header.value = params[0][1]

          for (let [key, val] of params.slice(1)) {
            switch (key.toLowerCase()) {
              case 'domain':
                header.domain = val
                break
              case 'expires': {
                if (typeof val === 'string') {
                  let date = new Date(val)
                  if (isValidDate(date)) {
                    header.expires = date
                  }
                }
                break
              }
              case 'httponly':
                header.httpOnly = true
                break
              case 'max-age': {
                if (typeof val === 'string') {
                  let v = parseInt(val, 10)
                  if (!isNaN(v)) header.maxAge = v
                }
                break
              }
              case 'partitioned':
                header.partitioned = true
                break
              case 'path':
                header.path = val
                break
              case 'samesite':
                if (typeof val === 'string' && /strict|lax|none/i.test(val)) {
                  header.sameSite = capitalize(val) as SameSiteValue
                }
                break
              case 'secure':
                header.secure = true
                break
            }
          }
        }
      } else {
        header.domain = value.domain
        header.expires = value.expires
        header.httpOnly = value.httpOnly
        header.maxAge = value.maxAge
        header.name = value.name
        header.partitioned = value.partitioned
        header.path = value.path
        header.sameSite = value.sameSite
        header.secure = value.secure
        header.value = value.value
      }
    }

    return header
  }
}