import { useEffect, useRef, useState, type KeyboardEvent } from 'react';
import type { ShellEntry } from '../client/useAgent';
import { iconFor, shortPath } from '../lib/format';
import { makeZip } from '../lib/zip';

interface Props {
  files: Record<string, string>;
  shell: ShellEntry[];
  busy: string | null;
  onSave: (path: string, content: string) => Promise<boolean>;
  onRun: (command: string) => Promise<void>;
  onClearShell: () => void;
  onError: (message: string) => void;
}

const MAX_BYTES = 1024 ** 2;

export function WorkspacePanel({ files, shell, busy, onSave, onRun, onClearShell, onError }: Props) {
  const paths = Object.keys(files).sort();
  const [selected, setSelected] = useState<string | null>(null);
  const [text, setText] = useState('');
  const [dirty, setDirty] = useState(false);
  const [adding, setAdding] = useState(false);
  const [newName, setNewName] = useState('');
  const [command, setCommand] = useState('');
  const history = useRef<string[]>([]);
  const cursor = useRef(-1);
  const outRef = useRef<HTMLDivElement>(null);

  // Chọn file đầu tiên khi có dữ liệu, hoặc khi file đang chọn bị xoá.
  useEffect(() => {
    if (paths.length === 0) return;
    if (selected === null || !(selected in files)) {
      setSelected(paths.find((p) => p.endsWith('README.md')) ?? paths[0]);
      setDirty(false);
    }
  }, [paths.join('|')]); // eslint-disable-line react-hooks/exhaustive-deps

  // Đồng bộ nội dung editor khi agent/shell đổi file (không ghi đè nếu bạn đang sửa dở).
  useEffect(() => {
    if (selected !== null && !dirty) setText(files[selected] ?? '');
  }, [selected, files, dirty]);

  useEffect(() => {
    const el = outRef.current;
    if (el) el.scrollTop = el.scrollHeight;
  }, [shell]);

  const save = async () => {
    if (selected === null) return;
    if (await onSave(selected, text)) setDirty(false);
  };

  const choose = (path: string) => {
    if (dirty && !window.confirm('Discard unsaved changes to this file?')) return;
    setSelected(path);
    setDirty(false);
  };

  const create = async (e: { preventDefault(): void }) => {
    e.preventDefault();
    const name = newName.trim().replace(/^\/+/, '');
    if (!name) return;
    const path = '/workspace/' + name;
    if (await onSave(path, '')) {
      setSelected(path);
      setDirty(false);
      setAdding(false);
      setNewName('');
    }
  };

  const importFiles = async (list: FileList | null) => {
    for (const f of Array.from(list ?? [])) {
      if (f.size > MAX_BYTES) {
        onError(`${f.name} is larger than 1 MiB.`);
        continue;
      }
      await onSave('/workspace/' + f.name, await f.text());
    }
  };

  const exportZip = () => {
    const url = URL.createObjectURL(makeZip(files));
    const a = document.createElement('a');
    a.href = url;
    a.download = 'pi-workspace.zip';
    a.click();
    setTimeout(() => URL.revokeObjectURL(url), 1000);
  };

  const run = async () => {
    const cmd = command.trim();
    if (!cmd) return;
    history.current.push(cmd);
    cursor.current = history.current.length;
    setCommand('');
    await onRun(cmd);
  };

  const onShellKey = (e: KeyboardEvent<HTMLTextAreaElement>) => {
    if (e.nativeEvent.isComposing) return;
    if (e.key === 'Enter' && !e.shiftKey) {
      e.preventDefault();
      void run();
    } else if (e.key === 'ArrowUp' && !command.includes('\n') && cursor.current > 0) {
      e.preventDefault();
      cursor.current -= 1;
      setCommand(history.current[cursor.current]);
    } else if (e.key === 'ArrowDown' && !command.includes('\n') && cursor.current >= 0) {
      e.preventDefault();
      cursor.current += 1;
      setCommand(history.current[cursor.current] ?? '');
    } else if (e.key === 'l' && e.ctrlKey) {
      e.preventDefault();
      onClearShell();
    }
  };

  return (
    <aside className="workspace" aria-label="Workspace">
      <div className="ws-head">
        <h2>Workspace</h2>
        <div>
          <button className="quiet" onClick={() => setAdding((v) => !v)}>+ File</button>
          <label className="quiet" style={{ display: 'contents' }}>
            <button className="quiet" onClick={(e) => (e.currentTarget.nextElementSibling as HTMLInputElement).click()}>Import</button>
            <input type="file" multiple hidden onChange={(e) => { void importFiles(e.target.files); e.target.value = ''; }} />
          </label>
          <button className="quiet" onClick={exportZip} disabled={paths.length === 0}>Export</button>
        </div>
      </div>

      <div className="files-area">
        <nav className="files" aria-label="Files">
          {adding && (
            <form className="addfile" onSubmit={create}>
              <label className="sr" htmlFor="newfile">File name</label>
              <input id="newfile" type="text" autoFocus placeholder="notes.md" value={newName} onChange={(e) => setNewName(e.target.value)} />
            </form>
          )}
          {paths.map((p) => (
            <button key={p} className="file quiet" aria-current={p === selected} onClick={() => choose(p)} title={p}>
              <img src={`${import.meta.env.BASE_URL}file-icons/${iconFor(p)}.svg`} alt="" />
              <span>{shortPath(p)}</span>
            </button>
          ))}
        </nav>
        <div className="editor">
          <div className="editor-head">
            <span>{selected ? shortPath(selected) + (dirty ? ' •' : '') : 'Select a file'}</span>
            <button className="quiet" onClick={save} disabled={!dirty || busy !== null}>Save</button>
          </div>
          <label className="sr" htmlFor="editor">File contents</label>
          <textarea
            id="editor"
            wrap="off"
            spellCheck={false}
            autoCapitalize="off"
            autoComplete="off"
            value={text}
            disabled={selected === null}
            placeholder="Select a file to inspect or edit it."
            onChange={(e) => { setText(e.target.value); setDirty(true); }}
            onKeyDown={(e) => {
              if ((e.ctrlKey || e.metaKey) && e.key === 's') { e.preventDefault(); void save(); }
            }}
          />
        </div>
      </div>

      <details className="shell" open>
        <summary>Shell · just-bash · /workspace</summary>
        <div className="shell-body">
          <div className="shell-out" ref={outRef} role="log" aria-label="Shell output" tabIndex={0}>
            {shell.length === 0 && <span className="code">Try <code>ls -la</code> or <code>cat README.md</code>.</span>}
            {shell.map((s) => (
              <div key={s.id}>
                <pre className="cmd">$ {s.command}</pre>
                {s.result.stdout && <pre>{s.result.stdout}</pre>}
                {s.result.stderr && <pre className="stderr">{s.result.stderr}</pre>}
                {s.result.exitCode !== 0 && <pre className="code">exit {s.result.exitCode}</pre>}
              </div>
            ))}
          </div>
          <form className="shell-form" onSubmit={(e) => { e.preventDefault(); void run(); }}>
            <span aria-hidden="true">$</span>
            <label className="sr" htmlFor="command">Shell command</label>
            <textarea id="command" rows={1} spellCheck={false} autoCapitalize="off" autoComplete="off" placeholder="Enter a shell command…"
              value={command} onChange={(e) => setCommand(e.target.value)} onKeyDown={onShellKey} />
            <button className="primary" type="submit" disabled={busy !== null || !command.trim()}>Run</button>
          </form>
        </div>
      </details>
      <p className="note">Bash, text tools and a virtual filesystem. Node.js, Python and network commands are unavailable.</p>
    </aside>
  );
}