import { Alert, AlertDescription } from '@/components/ui/alert';
import { Button } from '@/components/ui/button';
import { cn } from '@/lib/utils';
import type { ToolUIPart } from 'ai';
import { type ComponentProps, createContext, type ReactNode, useContext } from 'react';

type ToolUIPartApproval =
  | {
      id: string;
      approved?: never;
      reason?: never;
    }
  | {
      id: string;
      approved: boolean;
      reason?: string;
    }
  | {
      id: string;
      approved: true;
      reason?: string;
    }
  | {
      id: string;
      approved: true;
      reason?: string;
    }
  | {
      id: string;
      approved: false;
      reason?: string;
    }
  | undefined;

type ConfirmationContextValue = {
  approval: ToolUIPartApproval;
  state: ToolUIPart['state'];
};

const ConfirmationContext = createContext<ConfirmationContextValue | null>(null);

const useConfirmation = () => {
  const context = useContext(ConfirmationContext);

  if (!context) {
    throw new Error('Confirmation components must be used within Confirmation');
  }

  return context;
};

export type ConfirmationProps = ComponentProps<typeof Alert> & {
  approval?: ToolUIPartApproval;
  state: ToolUIPart['state'];
};

export const Confirmation = ({ className, approval, state, ...props }: ConfirmationProps) => {
  if (!approval || state === 'input-streaming' || state === 'input-available') {
    return null;
  }

  return (
    <ConfirmationContext.Provider value={{ approval, state }}>
      <Alert className={cn('flex flex-col gap-2', className)} {...props} />
    </ConfirmationContext.Provider>
  );
};

export type ConfirmationTitleProps = ComponentProps<typeof AlertDescription>;

export const ConfirmationTitle = ({ className, ...props }: ConfirmationTitleProps) => (
  <AlertDescription className={cn('inline', className)} {...props} />
);

export type ConfirmationRequestProps = {
  children?: ReactNode;
};

export const ConfirmationRequest = ({ children }: ConfirmationRequestProps) => {
  const { state } = useConfirmation();

  // Only show when approval is requested
  if (state !== 'approval-requested') {
    return null;
  }

  return children;
};

export type ConfirmationAcceptedProps = {
  children?: ReactNode;
};

export const ConfirmationAccepted = ({ children }: ConfirmationAcceptedProps) => {
  const { approval, state } = useConfirmation();

  // Only show when approved and in response states
  if (
    !approval?.approved ||
    (state !== 'approval-responded' && state !== 'output-denied' && state !== 'output-available')
  ) {
    return null;
  }

  return children;
};

export type ConfirmationRejectedProps = {
  children?: ReactNode;
};

export const ConfirmationRejected = ({ children }: ConfirmationRejectedProps) => {
  const { approval, state } = useConfirmation();

  // Only show when rejected and in response states
  if (
    approval?.approved !== false ||
    (state !== 'approval-responded' && state !== 'output-denied' && state !== 'output-available')
  ) {
    return null;
  }

  return children;
};

export type ConfirmationActionsProps = ComponentProps<'div'>;

export const ConfirmationActions = ({ className, ...props }: ConfirmationActionsProps) => {
  const { state } = useConfirmation();

  // Only show when approval is requested
  if (state !== 'approval-requested') {
    return null;
  }

  return (
    <div className={cn('flex items-center justify-end gap-2 self-end', className)} {...props} />
  );
};

export type ConfirmationActionProps = ComponentProps<typeof Button>;

export const ConfirmationAction = (props: ConfirmationActionProps) => (
  <Button className="h-8 px-3 text-sm" type="button" {...props} />
);