import { memo, useEffect, useMemo, useState, type ReactNode } from 'react';
import type { FileMap } from '../../lib/stores/files';
import { classNames } from '../../utils/classNames';
import { renderLogger } from '../../utils/logger';

const NODE_PADDING_LEFT = 12;
const DEFAULT_HIDDEN_FILES = [/\/node_modules\//];

interface Props {
  files?: FileMap;
  selectedFile?: string;
  onFileSelect?: (filePath: string) => void;
  rootFolder?: string;
  hiddenFiles?: Array<string | RegExp>;
  unsavedFiles?: Set<string>;
  className?: string;
}

export const FileTree = memo(
  ({ files = {}, onFileSelect, selectedFile, rootFolder, hiddenFiles, className, unsavedFiles }: Props) => {
    renderLogger.trace('FileTree');

    const computedHiddenFiles = useMemo(() => [...DEFAULT_HIDDEN_FILES, ...(hiddenFiles ?? [])], [hiddenFiles]);

    const fileList = useMemo(() => {
      return buildFileList(files, rootFolder, computedHiddenFiles);
    }, [files, rootFolder, computedHiddenFiles]);

    const [collapsedFolders, setCollapsedFolders] = useState(() => new Set<string>());

    useEffect(() => {
      setCollapsedFolders((prevCollapsed) => {
        const newCollapsed = new Set<string>();

        for (const folder of fileList) {
          if (folder.kind === 'folder' && prevCollapsed.has(folder.fullPath)) {
            newCollapsed.add(folder.fullPath);
          }
        }

        return newCollapsed;
      });
    }, [fileList]);

    const filteredFileList = useMemo(() => {
      const list = [];

      let lastDepth = Number.MAX_SAFE_INTEGER;

      for (const fileOrFolder of fileList) {
        const depth = fileOrFolder.depth;

        // if the depth is equal we reached the end of the collaped group
        if (lastDepth === depth) {
          lastDepth = Number.MAX_SAFE_INTEGER;
        }

        // ignore collapsed folders
        if (collapsedFolders.has(fileOrFolder.fullPath)) {
          lastDepth = Math.min(lastDepth, depth);
        }

        // ignore files and folders below the last collapsed folder
        if (lastDepth < depth) {
          continue;
        }

        list.push(fileOrFolder);
      }

      return list;
    }, [fileList, collapsedFolders]);

    const toggleCollapseState = (fullPath: string) => {
      setCollapsedFolders((prevSet) => {
        const newSet = new Set(prevSet);

        if (newSet.has(fullPath)) {
          newSet.delete(fullPath);
        } else {
          newSet.add(fullPath);
        }

        return newSet;
      });
    };

    return (
      <div className={className}>
        {filteredFileList.map((fileOrFolder) => {
          switch (fileOrFolder.kind) {
            case 'file': {
              return (
                <File
                  key={fileOrFolder.id}
                  selected={selectedFile === fileOrFolder.fullPath}
                  file={fileOrFolder}
                  unsavedChanges={unsavedFiles?.has(fileOrFolder.fullPath)}
                  onClick={() => {
                    onFileSelect?.(fileOrFolder.fullPath);
                  }}
                />
              );
            }
            case 'folder': {
              return (
                <Folder
                  key={fileOrFolder.id}
                  folder={fileOrFolder}
                  collapsed={collapsedFolders.has(fileOrFolder.fullPath)}
                  onClick={() => {
                    toggleCollapseState(fileOrFolder.fullPath);
                  }}
                />
              );
            }
            default: {
              return undefined;
            }
          }
        })}
      </div>
    );
  },
);

export default FileTree;

interface FolderProps {
  folder: FolderNode;
  collapsed: boolean;
  onClick: () => void;
}

function Folder({ folder: { depth, name }, collapsed, onClick }: FolderProps) {
  return (
    <NodeButton
      className="group bg-white hover:bg-gray-50 text-md"
      depth={depth}
      iconClasses={classNames({
        'i-ph:caret-right scale-98': collapsed,
        'i-ph:caret-down scale-98': !collapsed,
      })}
      onClick={onClick}
    >
      {name}
    </NodeButton>
  );
}

interface FileProps {
  file: FileNode;
  selected: boolean;
  unsavedChanges?: boolean;
  onClick: () => void;
}

function File({ file: { depth, name }, onClick, selected, unsavedChanges = false }: FileProps) {
  return (
    <NodeButton
      className={classNames('group', {
        'bg-white hover:bg-gray-50': !selected,
        'bg-gray-100': selected,
      })}
      depth={depth}
      iconClasses={classNames('i-ph:file-duotone scale-98', {
        'text-gray-600': !selected,
      })}
      onClick={onClick}
    >
      <div className="flex items-center">
        <div className="flex-1 truncate pr-2">{name}</div>
        {unsavedChanges && <span className="i-ph:circle-fill scale-68 shrink-0 text-warning-400" />}
      </div>
    </NodeButton>
  );
}

interface ButtonProps {
  depth: number;
  iconClasses: string;
  children: ReactNode;
  className?: string;
  onClick?: () => void;
}

function NodeButton({ depth, iconClasses, onClick, className, children }: ButtonProps) {
  return (
    <button
      className={`flex items-center gap-1.5 w-full pr-2 border-2 border-transparent text-faded ${className ?? ''}`}
      style={{ paddingLeft: `${12 + depth * NODE_PADDING_LEFT}px` }}
      onClick={() => onClick?.()}
    >
      <div className={classNames('scale-120 shrink-0', iconClasses)}></div>
      <div className="truncate w-full text-left">{children}</div>
    </button>
  );
}

type Node = FileNode | FolderNode;

interface BaseNode {
  id: number;
  depth: number;
  name: string;
  fullPath: string;
}

interface FileNode extends BaseNode {
  kind: 'file';
}

interface FolderNode extends BaseNode {
  kind: 'folder';
}

function buildFileList(files: FileMap, rootFolder = '/', hiddenFiles: Array<string | RegExp>): Node[] {
  const folderPaths = new Set<string>();
  const fileList: Node[] = [];

  let defaultDepth = 0;

  if (rootFolder === '/') {
    defaultDepth = 1;
    fileList.push({ kind: 'folder', name: '/', depth: 0, id: 0, fullPath: '/' });
  }

  for (const [filePath, dirent] of Object.entries(files)) {
    const segments = filePath.split('/').filter((segment) => segment);
    const fileName = segments.at(-1);

    if (!fileName || isHiddenFile(filePath, fileName, hiddenFiles)) {
      continue;
    }

    let currentPath = '';

    let i = 0;
    let depth = 0;

    while (i < segments.length) {
      const name = segments[i];
      const fullPath = (currentPath += `/${name}`);

      if (!fullPath.startsWith(rootFolder)) {
        i++;
        continue;
      }

      if (i === segments.length - 1 && dirent?.type === 'file') {
        fileList.push({
          kind: 'file',
          id: fileList.length,
          name,
          fullPath,
          depth: depth + defaultDepth,
        });
      } else if (!folderPaths.has(fullPath)) {
        folderPaths.add(fullPath);

        fileList.push({
          kind: 'folder',
          id: fileList.length,
          name,
          fullPath,
          depth: depth + defaultDepth,
        });
      }

      i++;
      depth++;
    }
  }

  return fileList;
}

function isHiddenFile(filePath: string, fileName: string, hiddenFiles: Array<string | RegExp>) {
  return hiddenFiles.some((pathOrRegex) => {
    if (typeof pathOrRegex === 'string') {
      return fileName === pathOrRegex;
    }

    return pathOrRegex.test(filePath);
  });
}