import Elementary
import Vapor
import VaporElementary

extension Request {
  func ensureValidContent<T>(_ decoding: T.Type) throws -> T where T: Content, T: Validatable {
    try T.validate(content: self)
    return try content.decode(T.self)
  }

  func ensureIDPathComponent<T: LosslessStringConvertible>(
    as decoding: T.Type = UUID.self,
    key: String = "id"
  ) throws -> T {
    guard let id = parameters.get(key, as: T.self) else {
      throw Abort(.badRequest, reason: "Id not supplied.")
    }
    return id
  }

  var isHtmxRequest: Bool {
    headers.contains(name: "hx-request")
  }

  func render<C: HTML>(
    @HTMLBuilder html: () async throws -> C
  ) async rethrows -> HTMLResponse where C: Sendable {
    let html = try await html()
    return HTMLResponse { html }
  }

  // Render the html if we're an htmx request, otherwise render the main page.
  func render<C: HTML, D: SendableHTMLDocument>(
    mainPage: (C) async throws -> D,
    @HTMLBuilder html: () async throws -> C
  ) async rethrows -> HTMLResponse where C: Sendable {
    let html = try await html()
    guard isHtmxRequest else {
      return try await render { try await mainPage(html) }
    }
    return HTMLResponse { html }
  }
}