"use client";

import { useEffect, useRef, useState, memo, useCallback, useMemo } from "react";
import { Textarea } from "@kandev/ui/textarea";
import { Tooltip, TooltipContent, TooltipTrigger } from "@kandev/ui/tooltip";
import { IconPaperclip } from "@tabler/icons-react";
import { Combobox } from "./combobox";
import {
  processFile,
  formatBytes,
  MAX_FILES,
  MAX_TOTAL_SIZE,
  type FileAttachment,
} from "@/components/task/chat/file-attachment";
import { ContextZone } from "@/components/task/chat/context-items/context-zone";
import type { ContextItem, ImageContextItem, FileAttachmentContextItem } from "@/lib/types/context";
import type { TaskFormInputsHandle } from "@/components/task-create-dialog-types";
import { EnhancePromptButton } from "@/components/enhance-prompt-button";

const CURSOR_POINTER_CLASS = "cursor-pointer";

type RepositoryOption = {
  value: string;
  label: string;
  renderLabel: () => React.ReactNode;
};

type RepositorySelectorProps = {
  options: RepositoryOption[];
  value: string;
  onValueChange: (value: string) => void;
  disabled: boolean;
  placeholder: string;
  searchPlaceholder: string;
  emptyMessage: string;
  triggerClassName?: string;
};

export const RepositorySelector = memo(function RepositorySelector({
  options,
  value,
  onValueChange,
  disabled,
  placeholder,
  searchPlaceholder,
  emptyMessage,
  triggerClassName,
}: RepositorySelectorProps) {
  return (
    <Combobox
      options={options}
      value={value}
      onValueChange={onValueChange}
      placeholder={placeholder}
      searchPlaceholder={searchPlaceholder}
      emptyMessage={emptyMessage}
      disabled={disabled}
      dropdownLabel="Repository"
      className={disabled ? undefined : CURSOR_POINTER_CLASS}
      triggerClassName={triggerClassName}
      testId="repository-selector"
    />
  );
});

type BranchOption = {
  value: string;
  label: string;
  renderLabel: () => React.ReactNode;
};

type BranchSelectorProps = {
  options: BranchOption[];
  value: string;
  onValueChange: (value: string) => void;
  disabled: boolean;
  placeholder: string;
  searchPlaceholder: string;
  emptyMessage: string;
};

export const BranchSelector = memo(function BranchSelector({
  options,
  value,
  onValueChange,
  disabled,
  placeholder,
  searchPlaceholder,
  emptyMessage,
}: BranchSelectorProps) {
  return (
    <Combobox
      options={options}
      value={value}
      onValueChange={onValueChange}
      placeholder={placeholder}
      searchPlaceholder={searchPlaceholder}
      emptyMessage={emptyMessage}
      disabled={disabled}
      dropdownLabel="Base Branch"
      className={disabled ? undefined : CURSOR_POINTER_CLASS}
      testId="branch-selector"
    />
  );
});

type AgentSelectorProps = {
  options: Array<{ value: string; label: string; renderLabel: () => React.ReactNode }>;
  value: string;
  onValueChange: (value: string) => void;
  disabled: boolean;
  placeholder: string;
  triggerClassName?: string;
};

export const AgentSelector = memo(function AgentSelector({
  options,
  value,
  onValueChange,
  disabled,
  placeholder,
  triggerClassName,
}: AgentSelectorProps) {
  return (
    <Combobox
      options={options}
      value={value}
      onValueChange={onValueChange}
      placeholder={placeholder}
      searchPlaceholder="Search agents..."
      emptyMessage="No agent found."
      disabled={disabled}
      dropdownLabel="Agent Profile"
      className={`min-w-[380px]${disabled ? "" : ` ${CURSOR_POINTER_CLASS}`}`}
      triggerClassName={triggerClassName}
      testId="agent-profile-selector"
    />
  );
});

type ExecutorSelectorProps = {
  options: Array<{ value: string; label: string; renderLabel?: () => React.ReactNode }>;
  value: string;
  onValueChange: (value: string) => void;
  disabled: boolean;
  placeholder: string;
  triggerClassName?: string;
};

export const ExecutorSelector = memo(function ExecutorSelector({
  options,
  value,
  onValueChange,
  disabled,
  placeholder,
  triggerClassName,
}: ExecutorSelectorProps) {
  return (
    <Combobox
      options={options}
      value={value}
      onValueChange={onValueChange}
      placeholder={placeholder}
      emptyMessage="No executor found."
      disabled={disabled}
      dropdownLabel="Executor"
      className={disabled ? undefined : CURSOR_POINTER_CLASS}
      triggerClassName={triggerClassName}
      showSearch={false}
    />
  );
});

type ExecutorProfileSelectorProps = {
  options: Array<{ value: string; label: string; renderLabel?: () => React.ReactNode }>;
  value: string;
  onValueChange: (value: string) => void;
  disabled: boolean;
  placeholder: string;
  triggerClassName?: string;
};

export const ExecutorProfileSelector = memo(function ExecutorProfileSelector({
  options,
  value,
  onValueChange,
  disabled,
  placeholder,
  triggerClassName,
}: ExecutorProfileSelectorProps) {
  return (
    <Combobox
      options={options}
      value={value}
      onValueChange={onValueChange}
      placeholder={placeholder}
      searchPlaceholder="Search profiles..."
      emptyMessage="No profile found."
      disabled={disabled}
      dropdownLabel="Executor Profile"
      className={disabled ? undefined : CURSOR_POINTER_CLASS}
      triggerClassName={triggerClassName}
      testId="executor-profile-selector"
    />
  );
});

type InlineTaskNameProps = {
  value: string;
  onChange: (value: string) => void;
  autoFocus?: boolean;
};

export const InlineTaskName = memo(function InlineTaskName({
  value,
  onChange,
  autoFocus,
}: InlineTaskNameProps) {
  const inputRef = useRef<HTMLInputElement>(null);

  useEffect(() => {
    if (autoFocus && inputRef.current) {
      inputRef.current.focus();
      inputRef.current.select();
    }
  }, [autoFocus]);

  return (
    <input
      ref={inputRef}
      type="text"
      value={value}
      onChange={(e) => onChange(e.target.value)}
      placeholder="task-name"
      data-testid="task-title-input"
      size={Math.max(value.length, 9)}
      className="bg-transparent border-none outline-none focus:ring-0 text-sm font-medium min-w-0 rounded-md px-1.5 py-0.5 -mx-1.5 hover:bg-muted focus:bg-muted transition-colors"
    />
  );
});

// Memoized description input to prevent re-rendering the entire dialog on every keystroke
type TaskFormInputsProps = {
  isSessionMode: boolean;
  autoFocus?: boolean;
  initialDescription: string;
  onDescriptionChange: (hasContent: boolean) => void;
  onKeyDown: (e: React.KeyboardEvent) => void;
  descriptionValueRef: React.RefObject<TaskFormInputsHandle | null>;
  disabled?: boolean;
  placeholder?: string;
  onEnhancePrompt?: () => void;
  isEnhancingPrompt?: boolean;
  isUtilityConfigured?: boolean;
};

function useFileAttachments() {
  const [attachments, setAttachments] = useState<FileAttachment[]>([]);
  const [isDragging, setIsDragging] = useState(false);

  const addFiles = useCallback(async (files: File[]) => {
    const processed: FileAttachment[] = [];
    for (const file of files) {
      const attachment = await processFile(file);
      if (attachment) processed.push(attachment);
    }
    if (processed.length === 0) return;

    setAttachments((prev) => {
      let nextCount = prev.length;
      let nextTotalSize = prev.reduce((sum, att) => sum + att.size, 0);
      const accepted: FileAttachment[] = [];
      for (const att of processed) {
        if (nextCount >= MAX_FILES) break;
        if (nextTotalSize + att.size > MAX_TOTAL_SIZE) break;
        accepted.push(att);
        nextCount += 1;
        nextTotalSize += att.size;
      }
      if (nextCount >= MAX_FILES && accepted.length < processed.length) {
        console.warn(`Maximum ${MAX_FILES} files allowed`);
      } else if (accepted.length < processed.length) {
        console.warn(`Total attachment size limit exceeded (max: ${formatBytes(MAX_TOTAL_SIZE)})`);
      }
      return accepted.length > 0 ? [...prev, ...accepted] : prev;
    });
  }, []);

  const handleRemoveAttachment = useCallback((id: string) => {
    setAttachments((prev) => prev.filter((att) => att.id !== id));
  }, []);

  return { attachments, isDragging, setIsDragging, addFiles, handleRemoveAttachment };
}

function useAttachmentHandlers(
  disabled: boolean | undefined,
  addFiles: (files: File[]) => Promise<void>,
  setIsDragging: (v: boolean) => void,
) {
  const handlePaste = useCallback(
    (e: React.ClipboardEvent<HTMLTextAreaElement>) => {
      if (disabled) return;
      const items = e.clipboardData?.items;
      if (!items) return;
      const files: File[] = [];
      for (const item of items) {
        if (item.kind === "file") {
          const file = item.getAsFile();
          if (file) files.push(file);
        }
      }
      if (files.length > 0) {
        e.preventDefault();
        void addFiles(files);
      }
    },
    [disabled, addFiles],
  );

  const handleDragOver = useCallback(
    (e: React.DragEvent) => {
      if (disabled) return;
      e.preventDefault();
      e.stopPropagation();
      setIsDragging(true);
    },
    [disabled, setIsDragging],
  );

  const handleDragLeave = useCallback(
    (e: React.DragEvent) => {
      e.preventDefault();
      e.stopPropagation();
      const rect = e.currentTarget.getBoundingClientRect();
      const { clientX, clientY } = e;
      if (
        clientX <= rect.left ||
        clientX >= rect.right ||
        clientY <= rect.top ||
        clientY >= rect.bottom
      ) {
        setIsDragging(false);
      }
    },
    [setIsDragging],
  );

  const handleDrop = useCallback(
    (e: React.DragEvent) => {
      e.preventDefault();
      e.stopPropagation();
      setIsDragging(false);
      if (disabled) return;
      const files = Array.from(e.dataTransfer.files).filter((f) => f.size > 0 || f.type !== "");
      if (files.length > 0) {
        void addFiles(files);
      }
    },
    [disabled, addFiles, setIsDragging],
  );

  return { handlePaste, handleDragOver, handleDragLeave, handleDrop };
}

function toContextItems(
  attachments: FileAttachment[],
  onRemove: (id: string) => void,
): ContextItem[] {
  return attachments.map((att) =>
    att.isImage
      ? ({
          kind: "image" as const,
          id: `image:${att.id}`,
          label: `Image (${formatBytes(att.size)})`,
          attachment: att,
          onRemove: () => onRemove(att.id),
        } as ImageContextItem)
      : ({
          kind: "file-attachment" as const,
          id: `file:${att.id}`,
          label: att.fileName,
          attachment: att,
          onRemove: () => onRemove(att.id),
        } as FileAttachmentContextItem),
  );
}

function AttachButton({ onClick, disabled }: { onClick: () => void; disabled?: boolean }) {
  return (
    <div className="flex items-center px-1 pb-1">
      <Tooltip>
        <TooltipTrigger asChild>
          <button
            type="button"
            aria-label="Attach files"
            className={`h-7 w-7 inline-flex items-center justify-center rounded-md text-muted-foreground hover:bg-muted/40 hover:text-foreground ${disabled ? "cursor-not-allowed opacity-50" : "cursor-pointer"}`}
            onClick={onClick}
            disabled={disabled}
          >
            <IconPaperclip className="h-4 w-4" />
          </button>
        </TooltipTrigger>
        <TooltipContent>Attach files</TooltipContent>
      </Tooltip>
    </div>
  );
}

function useDescriptionInput(
  initialDescription: string,
  autoFocus: boolean | undefined,
  descriptionValueRef: React.RefObject<TaskFormInputsHandle | null>,
  onDescriptionChange: (hasContent: boolean) => void,
  attachments: FileAttachment[],
) {
  const [description, setDescription] = useState(initialDescription);
  const textareaRef = useRef<HTMLTextAreaElement>(null);

  useEffect(() => {
    const ref = descriptionValueRef as React.MutableRefObject<TaskFormInputsHandle | null>;
    if (ref) {
      ref.current = {
        getValue: () => description,
        setValue: (v: string) => {
          setDescription(v);
          onDescriptionChange(v.trim().length > 0);
        },
        getAttachments: () => attachments,
      };
    }
  }, [description, attachments, descriptionValueRef, onDescriptionChange]);

  useEffect(() => {
    const textarea = textareaRef.current;
    if (!textarea) return;
    textarea.style.height = "auto";
    textarea.style.height = `${textarea.scrollHeight}px`;
  }, [description]);

  useEffect(() => {
    if (!autoFocus) return;
    const textarea = textareaRef.current;
    if (!textarea) return;
    textarea.focus();
    textarea.setSelectionRange(textarea.value.length, textarea.value.length);
  }, [autoFocus]);

  const handleDescriptionChange = useCallback(
    (e: React.ChangeEvent<HTMLTextAreaElement>) => {
      const newValue = e.target.value;
      const hadContent = description.trim().length > 0;
      const hasContent = newValue.trim().length > 0;
      setDescription(newValue);
      if (hadContent !== hasContent) onDescriptionChange(hasContent);
    },
    [description, onDescriptionChange],
  );

  return { description, textareaRef, handleDescriptionChange };
}

export const TaskFormInputs = memo(function TaskFormInputs({
  isSessionMode,
  autoFocus,
  initialDescription,
  onDescriptionChange,
  onKeyDown,
  descriptionValueRef,
  disabled,
  placeholder,
  onEnhancePrompt,
  isEnhancingPrompt,
  isUtilityConfigured,
}: TaskFormInputsProps) {
  const fileInputRef = useRef<HTMLInputElement>(null);
  const { attachments, isDragging, setIsDragging, addFiles, handleRemoveAttachment } =
    useFileAttachments();
  const { handlePaste, handleDragOver, handleDragLeave, handleDrop } = useAttachmentHandlers(
    disabled,
    addFiles,
    setIsDragging,
  );
  const contextItems = useMemo(
    () => toContextItems(attachments, handleRemoveAttachment),
    [attachments, handleRemoveAttachment],
  );
  const { description, textareaRef, handleDescriptionChange } = useDescriptionInput(
    initialDescription,
    autoFocus,
    descriptionValueRef,
    onDescriptionChange,
    attachments,
  );
  const handleAttachClick = useCallback(() => fileInputRef.current?.click(), []);
  const handleFileInputChange = useCallback(
    (e: React.ChangeEvent<HTMLInputElement>) => {
      const files = e.target.files;
      if (files && files.length > 0) void addFiles(Array.from(files));
      e.target.value = "";
    },
    [addFiles],
  );

  return (
    <div
      className="relative"
      onDragOver={handleDragOver}
      onDragLeave={handleDragLeave}
      onDrop={handleDrop}
    >
      <div
        className={`rounded-md border border-input bg-transparent ${contextItems.length > 0 ? "ring-0" : ""}`}
      >
        <ContextZone items={contextItems} />
        <Textarea
          ref={textareaRef}
          placeholder={
            placeholder ??
            (isSessionMode
              ? "Describe what you want the agent to do..."
              : "Write a prompt for the agent...")
          }
          value={description}
          onChange={handleDescriptionChange}
          onKeyDown={onKeyDown}
          onPaste={handlePaste}
          data-testid="task-description-input"
          rows={2}
          className={`border-0 focus-visible:ring-0 focus-visible:ring-offset-0 ${isSessionMode ? "min-h-[120px] max-h-[240px] resize-none overflow-auto text-[13px]" : "min-h-[96px] max-h-[240px] resize-y overflow-auto text-[13px]"}`}
          required={isSessionMode}
          disabled={disabled}
        />
        <div className="flex items-center px-1 pb-1">
          <AttachButton onClick={handleAttachClick} disabled={disabled} />
          {onEnhancePrompt && (
            <EnhancePromptButton
              onClick={onEnhancePrompt}
              isLoading={isEnhancingPrompt ?? false}
              isConfigured={isUtilityConfigured}
            />
          )}
        </div>
        <input
          ref={fileInputRef}
          type="file"
          multiple
          className="hidden"
          onChange={handleFileInputChange}
          tabIndex={-1}
        />
      </div>
      {isDragging && (
        <div className="absolute inset-0 flex items-center justify-center bg-primary/10 border-2 border-dashed border-primary rounded-md pointer-events-none">
          <span className="text-sm text-primary font-medium">Drop files here</span>
        </div>
      )}
    </div>
  );
});