import { useRef, useState } from 'react';
import { useDialogueStore } from '../../store/dialogueStore';
import { parseDialogueFile } from '../../utils/fileIO';
import { useValidation } from '../../hooks/useValidation';
import styles from './LeftPanel.module.css';

export function LeftPanel() {
  const { file, fileName, selectedDialogueId, loadFile, selectDialogue, createDialogue, deleteDialogue, duplicateDialogue, exportFile } = useDialogueStore();
  const { issuesByNodeId } = useValidation();
  const fileInputRef = useRef<HTMLInputElement>(null);
  const [newId, setNewId] = useState('');
  const [creating, setCreating] = useState(false);
  const [error, setError] = useState('');

  function handleFileChange(e: React.ChangeEvent<HTMLInputElement>) {
    const f = e.target.files?.[0];
    if (!f) return;
    const reader = new FileReader();
    reader.onload = (ev) => {
      try {
        const parsed = parseDialogueFile(ev.target?.result as string);
        loadFile(parsed, f.name);
        setError('');
      } catch (err) {
        setError(String(err));
      }
    };
    reader.readAsText(f);
    e.target.value = '';
  }

  function handleCreate() {
    if (!newId.trim()) return;
    if (file?.dialogues.some(d => d.id === newId.trim())) {
      setError(`ID "${newId.trim()}" already exists`);
      return;
    }
    createDialogue(newId.trim());
    setNewId('');
    setCreating(false);
    setError('');
  }

  function dialogueHasIssues(dialogueId: string) {
    // Simple check: are there any issues for nodes in this dialogue?
    // We only have current dialogue issues so we check if this is selected
    return selectedDialogueId === dialogueId && Object.keys(issuesByNodeId).length > 0;
  }

  function dialogueHasErrors(dialogueId: string) {
    return selectedDialogueId === dialogueId &&
      Object.values(issuesByNodeId).some(list => list.some(i => i.severity === 'error'));
  }

  return (
    <div className={styles.panel}>
      <div className={styles.header}>
        <span className={styles.title}>Dialogues</span>
        {file && <span className={styles.fileName}>{fileName}</span>}
      </div>

      <div className={styles.fileButtons}>
        <button className={styles.btn} onClick={() => fileInputRef.current?.click()}>
          📂 Load
        </button>
        <input
          ref={fileInputRef}
          type="file"
          accept=".json"
          style={{ display: 'none' }}
          onChange={handleFileChange}
        />
        {file && (
          <button className={[styles.btn, styles.btnSave].join(' ')} onClick={exportFile}>
            💾 Save
          </button>
        )}
      </div>

      {error && <div className={styles.errorMsg}>{error}</div>}

      <div className={styles.list}>
        {!file && (
          <div className={styles.emptyMsg}>Load a JSON file to start</div>
        )}
        {file?.dialogues.map(d => {
          const hasErr = dialogueHasErrors(d.id);
          const hasWarn = !hasErr && dialogueHasIssues(d.id);
          return (
            <div
              key={d.id}
              className={[
                styles.dialogueItem,
                d.id === selectedDialogueId ? styles.active : '',
              ].join(' ')}
              onClick={() => selectDialogue(d.id)}
            >
              <span className={styles.dialogueId}>
                {hasErr && <span className={styles.errDot} title="Has errors">●</span>}
                {hasWarn && <span className={styles.warnDot} title="Has warnings">●</span>}
                {d.mobileMode && <span className={styles.mobileDot} title="Mobile mode">📱</span>}
                {d.id}
              </span>
              <button
                className={styles.copyBtn}
                title="Duplicate dialogue"
                onClick={(e) => {
                  e.stopPropagation();
                  duplicateDialogue(d.id);
                }}
              >
                ⧉
              </button>
              <button
                className={styles.deleteBtn}
                title="Delete dialogue"
                onClick={(e) => {
                  e.stopPropagation();
                  if (confirm(`Delete "${d.id}"?`)) deleteDialogue(d.id);
                }}
              >
                ×
              </button>
            </div>
          );
        })}
      </div>

      <div className={styles.footer}>
        {creating ? (
          <div className={styles.createForm}>
            <input
              className={styles.createInput}
              value={newId}
              onChange={e => setNewId(e.target.value)}
              placeholder="dialogue_id"
              onKeyDown={e => {
                if (e.key === 'Enter') handleCreate();
                if (e.key === 'Escape') { setCreating(false); setNewId(''); }
              }}
              autoFocus
            />
            <button className={[styles.btn, styles.btnSave].join(' ')} onClick={handleCreate}>✓</button>
            <button className={styles.btn} onClick={() => { setCreating(false); setNewId(''); }}>✗</button>
          </div>
        ) : (
          file && (
            <button className={[styles.btn, styles.btnNew].join(' ')} onClick={() => setCreating(true)}>
              + New Dialogue
            </button>
          )
        )}
      </div>
    </div>
  );
}