import { useState } from 'react';
import { useAppState, useAppDispatch } from '../context/AppContext.jsx';
import Header from '../components/Header.jsx';
import { DEFAULT_CONFIG } from '../utils/constants.js';
import { buildAndDownload } from '../utils/excelExport.js';
import { showInfoToast, showWarnToast } from '../components/Toast.jsx';

function getByPath(obj, path) {
  if (!path) return obj;
  return path.split('.').reduce((o, k) => (o && o[k] !== undefined ? o[k] : undefined), obj);
}

function setByPath(obj, path, value) {
  if (!path) return value;
  const keys = path.split('.');
  const root = JSON.parse(JSON.stringify(obj));
  let cur = root;
  for (let i = 0; i < keys.length - 1; i++) { cur = cur[keys[i]]; }
  cur[keys[keys.length - 1]] = value;
  return root;
}

function ConfigNode({ obj, path, depth }) {
  const dispatch = useAppDispatch();
  const state = useAppState();
  const [collapsed, setCollapsed] = useState(depth > 1);

  function update(p, val) {
    const newConfig = setByPath(state.config, p, val);
    dispatch({ type: 'SET_CONFIG', payload: newConfig });
  }

  if (Array.isArray(obj)) {
    return (
      <div style={{ display: 'flex', alignItems: 'flex-start', gap: 6, padding: '2px 0', minHeight: 26 }}>
        <input
          type="text"
          className="cfg-inp cfg-inp-arr"
          defaultValue={obj.map(v => JSON.stringify(v)).join(', ')}
          title="Edit comma-separated values"
          onBlur={e => {
            try {
              const raw = e.target.value;
              const parsed = raw.split(',').map(s => {
                const t = s.trim();
                try { return JSON.parse(t); } catch { return t; }
              }).filter(v => v !== '');
              update(path, parsed);
            } catch (err) { showWarnToast('Invalid array format'); }
          }}
        />
        <span className="cfg-type-tag">array[{obj.length}]</span>
      </div>
    );
  }

  if (obj !== null && typeof obj === 'object') {
    const keys = Object.keys(obj);
    return (
      <div className="cfg-node">
        {depth > 0 && (
          <div
            className="cfg-obj-label"
            style={{ paddingBottom: 2 }}
            onClick={() => setCollapsed(!collapsed)}
          >
            <span style={{ fontSize: 9, color: 'var(--mt)', marginRight: 2, userSelect: 'none' }}>
              {collapsed ? '▶' : '▼'}
            </span>
            <span style={{ color: 'var(--mt)' }}>{'{' + keys.length + ' keys}'}</span>
          </div>
        )}
        {!collapsed && (
          <div className={depth > 0 ? 'cfg-children' : ''}>
            {keys.map(key => {
              const childPath = path ? `${path}.${key}` : key;
              const childVal = obj[key];
              return (
                <div key={key} className="cfg-node">
                  <div className="cfg-row">
                    <span className="cfg-key" style={{ marginTop: 4 }}>{key}</span>
                    <span className="cfg-sep" style={{ marginTop: 4 }}>:</span>
                    <ConfigNode obj={childVal} path={childPath} depth={depth + 1} />
                  </div>
                </div>
              );
            })}
          </div>
        )}
      </div>
    );
  }

  // Primitive leaf
  const isNum = typeof obj === 'number';
  const isBool = typeof obj === 'boolean';

  if (isBool) {
    return (
      <select
        className="cfg-inp"
        defaultValue={String(obj)}
        onChange={e => update(path, e.target.value === 'true')}
        style={{ width: 80 }}
      >
        <option value="true">true</option>
        <option value="false">false</option>
      </select>
    );
  }

  return (
    <input
      type={isNum ? 'number' : 'text'}
      className={`cfg-inp${isNum ? ' cfg-inp-num' : ''}`}
      defaultValue={obj}
      onBlur={e => {
        const raw = e.target.value;
        update(path, isNum ? (isNaN(Number(raw)) ? raw : Number(raw)) : raw);
      }}
    />
  );
}

export default function Step7Config({ onBack, onNav }) {
  const state = useAppState();
  const dispatch = useAppDispatch();
  const { config } = state;

  function resetConfig() {
    if (!window.confirm('Reset all config values to defaults?')) return;
    dispatch({ type: 'SET_CONFIG', payload: JSON.parse(JSON.stringify(DEFAULT_CONFIG)) });
  }

  function download() {
    const ok = buildAndDownload(state);
    if (ok) showInfoToast('Download complete — Dabur_Model_Output.xlsx');
  }

  return (
    <div className="page">
      <Header step={7} onNav={onNav} sub="Config Editor" />

      <div className="toolbar">
        <span style={{ fontSize: 11, fontWeight: 600, color: 'var(--tx)' }}>Model Configuration</span>
        <span className="page-note" style={{ marginLeft: 4 }}>Edit values inline · Click ▶ to expand objects</span>
        <div style={{ flex: 1 }} />
        <button className="btn btn-sm btn-sec" onClick={resetConfig}>Reset to Defaults</button>
      </div>

      <div style={{ flex: 1, overflow: 'auto', padding: '10px 14px', minHeight: 0 }}>
        <ConfigNode obj={config} path="" depth={0} />
      </div>

      <div className="nav-foot">
        <button className="btn btn-sec" onClick={onBack}><svg width="9" height="9" viewBox="0 0 12 12" fill="none" stroke="currentColor" strokeWidth="2.3" strokeLinecap="round"><path d="M10 6H2M5 2L1 6l4 4"/></svg> Back</button>
        <button className="btn btn-or" onClick={download}>
          <svg width="11" height="11" viewBox="0 0 16 16" fill="none" stroke="currentColor" strokeWidth="2" strokeLinecap="round"><path d="M8 2v8M5 7l3 3 3-3"/><path d="M2 12v1a1 1 0 001 1h10a1 1 0 001-1v-1"/></svg>
          Full Excel Output
        </button>
      </div>
    </div>
  );
}