import {
  Component,
  ContentChild,
  TemplateRef,
  Type,
  ViewChild,
  ElementRef,
  ChangeDetectionStrategy,
  ChangeDetectorRef,
  ViewEncapsulation,
  computed,
  signal,
  OnInit,
  OnChanges,
  OnDestroy,
  AfterViewInit,
  input,
  output,
} from "@angular/core";
import { CommonModule } from "@angular/common";
import { CopilotSlot } from "../../slots/copilot-slot";
import { CopilotChatViewScrollView } from "./copilot-chat-view-scroll-view";
import { CopilotChatViewScrollToBottomButton } from "./copilot-chat-view-scroll-to-bottom-button";
import { CopilotChatViewFeather } from "./copilot-chat-view-feather";
import { CopilotChatViewInputContainer } from "./copilot-chat-view-input-container";
import { CopilotChatViewDisclaimer } from "./copilot-chat-view-disclaimer";
import { Message } from "@ag-ui/client";
import { cn } from "../../utils";
import { ResizeObserverService } from "../../resize-observer";
import { CopilotChatViewHandlers } from "./copilot-chat-view-handlers";
import { Subject } from "rxjs";
import { takeUntil } from "rxjs/operators";

/**
 * CopilotChatView component - Angular port of the React component.
 * A complete chat interface with message feed and input components.
 *
 * @example
 * ```html
 * <copilot-chat-view
 *   [messages]="messages"
 *   [autoScroll]="true"
 *   [messageViewProps]="{ assistantMessage: { onThumbsUp: handleThumbsUp } }">
 * </copilot-chat-view>
 * ```
 */
@Component({
  standalone: true,
  selector: "copilot-chat-view",
  imports: [CommonModule, CopilotSlot, CopilotChatViewScrollView],
  changeDetection: ChangeDetectionStrategy.OnPush,
  encapsulation: ViewEncapsulation.None,
  providers: [ResizeObserverService, CopilotChatViewHandlers],
  template: `
    <!-- Custom layout template support (render prop pattern) -->
    @if (customLayoutTemplate) {
      <ng-container
        [ngTemplateOutlet]="customLayoutTemplate"
        [ngTemplateOutletContext]="layoutContext()"
      ></ng-container>
    } @else {
      <!-- Default layout - exact React DOM structure -->
      <div [class]="computedClass()">
        <!-- ScrollView -->
        <copilot-chat-view-scroll-view
          [autoScroll]="autoScrollSignal()"
          [inputContainerHeight]="inputContainerHeight()"
          [isResizing]="isResizing()"
          [messages]="messagesValue()"
          [messageView]="messageViewSlot()"
          [messageViewClass]="messageViewClass()"
          [scrollToBottomButton]="scrollToBottomButtonSlot()"
          [scrollToBottomButtonClass]="scrollToBottomButtonClass()"
          [showCursor]="showCursorSignal()"
          (assistantMessageThumbsUp)="assistantMessageThumbsUp.emit($event)"
          (assistantMessageThumbsDown)="assistantMessageThumbsDown.emit($event)"
          (assistantMessageReadAloud)="assistantMessageReadAloud.emit($event)"
          (assistantMessageRegenerate)="assistantMessageRegenerate.emit($event)"
          (userMessageCopy)="userMessageCopy.emit($event)"
          (userMessageEdit)="userMessageEdit.emit($event)"
        >
        </copilot-chat-view-scroll-view>

        <!-- Feather effect -->
        <copilot-slot
          [slot]="featherSlot()"
          [context]="{ inputClass: featherClass }"
          [defaultComponent]="defaultFeatherComponent"
        >
        </copilot-slot>

        <!-- Input container -->
        <copilot-slot
          #inputContainerSlotRef
          [slot]="inputContainerSlot()"
          [context]="inputContainerContext()"
          [defaultComponent]="defaultInputContainerComponent"
        >
        </copilot-slot>
      </div>
    }
  `,
})
export class CopilotChatView
  implements OnInit, OnChanges, AfterViewInit, OnDestroy
{
  // Core inputs matching React props
  messages = input<Message[]>([]);
  autoScroll = input<boolean>(true);
  showCursor = input<boolean>(false);

  // MessageView slot inputs
  messageViewComponent = input<Type<any> | undefined>(undefined);
  messageViewTemplate = input<TemplateRef<any> | undefined>(undefined);
  messageViewClass = input<string | undefined>(undefined);

  // ScrollView slot inputs
  scrollViewComponent = input<Type<any> | undefined>(undefined);
  scrollViewTemplate = input<TemplateRef<any> | undefined>(undefined);
  scrollViewClass = input<string | undefined>(undefined);

  // ScrollToBottomButton slot inputs
  scrollToBottomButtonComponent = input<Type<any> | undefined>(undefined);
  scrollToBottomButtonTemplate = input<TemplateRef<any> | undefined>(undefined);
  scrollToBottomButtonClass = input<string | undefined>(undefined);

  // Input slot inputs
  inputComponent = input<Type<any> | undefined>(undefined);
  inputTemplate = input<TemplateRef<any> | undefined>(undefined);

  // InputContainer slot inputs
  inputContainerComponent = input<Type<any> | undefined>(undefined);
  inputContainerTemplate = input<TemplateRef<any> | undefined>(undefined);
  inputContainerClass = input<string | undefined>(undefined);

  // Feather slot inputs
  featherComponent = input<Type<any> | undefined>(undefined);
  featherTemplate = input<TemplateRef<any> | undefined>(undefined);
  featherClass = input<string | undefined>(undefined);

  // Disclaimer slot inputs
  disclaimerComponent = input<Type<any> | undefined>(undefined);
  disclaimerTemplate = input<TemplateRef<any> | undefined>(undefined);
  disclaimerClass = input<string | undefined>(undefined);
  disclaimerText = input<string | undefined>(undefined);

  // Custom layout template (render prop pattern)
  @ContentChild("customLayout") customLayoutTemplate?: TemplateRef<any>;

  // Named template slots for deep customization
  @ContentChild("sendButton") sendButtonTemplate?: TemplateRef<any>;
  @ContentChild("toolbar") toolbarTemplate?: TemplateRef<any>;
  @ContentChild("textArea") textAreaTemplate?: TemplateRef<any>;
  @ContentChild("audioRecorder") audioRecorderTemplate?: TemplateRef<any>;
  @ContentChild("assistantMessageMarkdownRenderer")
  assistantMessageMarkdownRendererTemplate?: TemplateRef<any>;
  @ContentChild("thumbsUpButton") thumbsUpButtonTemplate?: TemplateRef<any>;
  @ContentChild("thumbsDownButton") thumbsDownButtonTemplate?: TemplateRef<any>;
  @ContentChild("readAloudButton") readAloudButtonTemplate?: TemplateRef<any>;
  @ContentChild("regenerateButton") regenerateButtonTemplate?: TemplateRef<any>;

  // Output events for assistant message actions (bubbled from child components)
  assistantMessageThumbsUp = output<{ message: Message }>();
  assistantMessageThumbsDown = output<{ message: Message }>();
  assistantMessageReadAloud = output<{ message: Message }>();
  assistantMessageRegenerate = output<{ message: Message }>();

  // Output events for user message actions (if applicable)
  userMessageCopy = output<{ message: Message }>();
  userMessageEdit = output<{ message: Message }>();

  // ViewChild references
  @ViewChild("inputContainerSlotRef", { read: ElementRef })
  inputContainerSlotRef?: ElementRef;

  // Default components for slots
  protected readonly defaultScrollViewComponent = CopilotChatViewScrollView;
  protected readonly defaultScrollToBottomButtonComponent =
    CopilotChatViewScrollToBottomButton;
  protected readonly defaultInputContainerComponent =
    CopilotChatViewInputContainer;
  protected readonly defaultFeatherComponent = CopilotChatViewFeather;
  protected readonly defaultDisclaimerComponent = CopilotChatViewDisclaimer;

  // Signals for reactive state
  protected messagesValue = computed(() => this.messages());
  protected autoScrollSignal = computed(() => this.autoScroll());
  protected showCursorSignal = computed(() => this.showCursor());
  protected disclaimerTextSignal = computed(() => this.disclaimerText());
  protected disclaimerClassSignal = computed(() => this.disclaimerClass());
  protected inputContainerHeight = signal<number>(0);
  protected isResizing = signal<boolean>(false);
  protected contentPaddingBottom = computed(
    () => this.inputContainerHeight() + 32,
  );

  // Computed signals
  protected computedClass = computed(() => cn("relative h-full"));

  // Slot resolution computed signals
  protected messageViewSlot = computed(
    () => this.messageViewTemplate() || this.messageViewComponent(),
  );

  protected scrollViewSlot = computed(
    () => this.scrollViewTemplate() || this.scrollViewComponent(),
  );

  protected scrollToBottomButtonSlot = computed(
    () =>
      this.scrollToBottomButtonTemplate() ||
      this.scrollToBottomButtonComponent(),
  );

  protected inputSlot = computed(
    () => this.inputTemplate() || this.inputComponent(),
  );

  protected inputContainerSlot = computed(
    () => this.inputContainerTemplate() || this.inputContainerComponent(),
  );

  protected featherSlot = computed(
    () => this.featherTemplate() || this.featherComponent(),
  );

  protected disclaimerSlot = computed(
    () => this.disclaimerTemplate() || this.disclaimerComponent(),
  );

  // Context objects for slots
  protected scrollViewContext = computed(() => ({
    autoScroll: this.autoScrollSignal(),
    scrollToBottomButton: this.scrollToBottomButtonSlot(),
    scrollToBottomButtonClass: this.scrollToBottomButtonClass(),
    inputContainerHeight: this.inputContainerHeight(),
    isResizing: this.isResizing(),
    messages: this.messagesValue(),
    messageView: this.messageViewSlot(),
    messageViewClass: this.messageViewClass(),
  }));

  // Removed scrollViewPropsComputed - no longer needed

  protected inputContainerContext = computed(() => ({
    input: this.inputSlot(),
    disclaimer: this.disclaimerSlot(),
    disclaimerText: this.disclaimerTextSignal(),
    disclaimerClass: this.disclaimerClassSignal(),
    inputContainerClass: this.inputContainerClass(),
  }));

  // Removed inputContainerPropsComputed - no longer needed

  // Layout context for custom templates (render prop pattern)
  protected layoutContext = computed(() => ({
    messageView: this.messageViewSlot(),
    input: this.inputSlot(),
    scrollView: this.scrollViewSlot(),
    scrollToBottomButton: this.scrollToBottomButtonSlot(),
    feather: this.featherSlot(),
    inputContainer: this.inputContainerSlot(),
    disclaimer: this.disclaimerSlot(),
  }));

  private destroy$ = new Subject<void>();
  private resizeTimeoutRef?: number;

  constructor(
    private resizeObserverService: ResizeObserverService,
    private cdr: ChangeDetectorRef,
    private handlers: CopilotChatViewHandlers,
  ) {
    // Clear any pending resize timeout when toggling isResizing, without signal writes here
  }

  ngOnInit(): void {
    // Initialize handler availability in the view-scoped service
    // OutputEmitterRef doesn't expose 'observed'; default to true to enable UI affordances
    this.handlers.hasAssistantThumbsUpHandler.set(true);
    this.handlers.hasAssistantThumbsDownHandler.set(true);
    this.handlers.hasAssistantReadAloudHandler.set(true);
    this.handlers.hasAssistantRegenerateHandler.set(true);
    this.handlers.hasUserCopyHandler.set(true);
    this.handlers.hasUserEditHandler.set(true);
  }

  ngOnChanges(): void {
    // Keep handler availability in sync (assume available)
    this.handlers.hasAssistantThumbsUpHandler.set(true);
    this.handlers.hasAssistantThumbsDownHandler.set(true);
    this.handlers.hasAssistantReadAloudHandler.set(true);
    this.handlers.hasAssistantRegenerateHandler.set(true);
    this.handlers.hasUserCopyHandler.set(true);
    this.handlers.hasUserEditHandler.set(true);
  }

  ngAfterViewInit(): void {
    // Don't set a default height - measure it dynamically

    // Set up input container height monitoring
    const measureAndObserve = () => {
      if (
        !this.inputContainerSlotRef ||
        !this.inputContainerSlotRef.nativeElement
      ) {
        return false;
      }

      // The slot ref points to the copilot-slot element
      // We need to find the actual input container component inside it
      const slotElement = this.inputContainerSlotRef.nativeElement;
      const componentElement = slotElement.querySelector(
        "copilot-chat-view-input-container",
      );

      if (!componentElement) {
        return false;
      }

      // Look for the absolute positioned div that contains the input
      let innerDiv = componentElement.querySelector(
        "div.absolute",
      ) as HTMLElement;

      // If not found by class, try first child
      if (!innerDiv) {
        innerDiv = componentElement.firstElementChild as HTMLElement;
      }

      if (!innerDiv) {
        return false;
      }

      // Measure the actual height
      const measuredHeight = innerDiv.offsetHeight;

      if (measuredHeight === 0) {
        return false;
      }

      // Success! Set the initial height
      this.inputContainerHeight.set(measuredHeight);
      this.cdr.detectChanges();

      // Create an ElementRef wrapper for ResizeObserver
      const innerDivRef = new ElementRef(innerDiv);

      // Set up ResizeObserver to track changes
      this.resizeObserverService
        .observeElement(innerDivRef, 0, 250)
        .pipe(takeUntil(this.destroy$))
        .subscribe((state) => {
          const newHeight = state.height;

          if (newHeight !== this.inputContainerHeight() && newHeight > 0) {
            this.inputContainerHeight.set(newHeight);
            this.isResizing.set(true);
            this.cdr.detectChanges();

            // Clear existing timeout
            if (this.resizeTimeoutRef) {
              clearTimeout(this.resizeTimeoutRef);
            }

            // Set isResizing to false after a short delay
            this.resizeTimeoutRef = window.setTimeout(() => {
              this.isResizing.set(false);
              this.resizeTimeoutRef = undefined;
              this.cdr.detectChanges();
            }, 250);
          }
        });

      return true;
    };

    // Try to measure immediately
    if (!measureAndObserve()) {
      // If failed, retry with increasing delays
      let attempts = 0;
      const maxAttempts = 10;

      const retry = () => {
        attempts++;
        if (measureAndObserve()) {
          // Successfully measured
        } else if (attempts < maxAttempts) {
          // Exponential backoff: 50ms, 100ms, 200ms, 400ms, etc.
          const delay = 50 * Math.pow(2, Math.min(attempts - 1, 4));
          setTimeout(retry, delay);
        } else {
          // Failed to measure after max attempts
        }
      };

      // Start retry with first delay
      setTimeout(retry, 50);
    }
  }

  ngOnDestroy(): void {
    if (this.resizeTimeoutRef) {
      clearTimeout(this.resizeTimeoutRef);
    }
    this.destroy$.next();
    this.destroy$.complete();
  }
}