const STORAGE_PREFIX = 'scenario:';
const MATCH_KEY = 'match:current';

function load(id) {
  try {
    const raw = localStorage.getItem(STORAGE_PREFIX + id);
    if (raw === null) {
      return null;
    }
    return JSON.parse(raw);
  } catch (e) {
    return null;
  }
}

function save(id, scenario) {
  const stamped = { ...scenario, lastModified: Date.now() };
  localStorage.setItem(STORAGE_PREFIX + id, JSON.stringify(stamped));
}

function remove(id) {
  localStorage.removeItem(STORAGE_PREFIX + id);
}

function listAll() {
  const items = [];
  for (let i = 0; i < localStorage.length; i += 1) {
    const key = localStorage.key(i);
    if (key !== null && key.startsWith(STORAGE_PREFIX)) {
      const id = key.slice(STORAGE_PREFIX.length);
      const scenario = load(id);
      if (scenario !== null) {
        items.push({
          id,
          name: typeof scenario.name === 'string' ? scenario.name : id,
          lastModified: typeof scenario.lastModified === 'number' ? scenario.lastModified : 0,
        });
      }
    }
  }
  items.sort((a, b) => b.lastModified - a.lastModified);
  return items;
}

function currentMatch() {
  try {
    const raw = localStorage.getItem(MATCH_KEY);
    if (raw === null) {
      return null;
    }
    return JSON.parse(raw);
  } catch (e) {
    return null;
  }
}

function setCurrentMatch(match) {
  localStorage.setItem(MATCH_KEY, JSON.stringify(match));
}

function removeCurrentMatch() {
  localStorage.removeItem(MATCH_KEY);
}

function getCsrfToken() {
  const meta = document.querySelector('meta[name="csrf-token"]');
  return meta ? meta.getAttribute('content') : '';
}

function parsePath(name) {
  const match = name.match(/^(teamA|teamB)\[units\]\[(\d+)\]\[(\w+)\]$/);
  if (match) {
    const [, team, indexStr, key] = match;
    const teamKey = team === 'teamA' ? 'teamA' : 'teamB';
    return [teamKey, 'units', Number(indexStr), key];
  }
  const simple = [
    'id',
    'name',
    'battlefieldWidth',
    'battlefieldHeight',
    'victoryCondition',
    'holdRoundsRequired',
  ];
  if (simple.includes(name)) {
    return [name];
  }
  return null;
}

function resolveField(scenario, path) {
  const parts = parsePath(path);
  if (parts === null) {
    return undefined;
  }
  let cursor = scenario;
  for (let i = 0; i < parts.length; i += 1) {
    if (cursor === null || cursor === undefined) {
      return undefined;
    }
    cursor = cursor[parts[i]];
  }
  return cursor;
}

function populateRecentScenarios() {
  const root = document.getElementById('recent');
  if (!root) {
    return;
  }
  while (root.firstChild) {
    root.removeChild(root.firstChild);
  }
  const items = listAll();
  if (items.length === 0) {
    const p = document.createElement('p');
    p.className = 'bf-empty';
    p.appendChild(document.createTextNode('No saved scenarios yet.'));
    root.appendChild(p);
    return;
  }
  const ul = document.createElement('ul');
  items.forEach((item) => {
    const li = document.createElement('li');
    const a = document.createElement('a');
    a.setAttribute('href', `/scenarios/${encodeURIComponent(item.id)}/edit/team`);
    a.appendChild(document.createTextNode(`${item.name} (${item.id})`));
    li.appendChild(a);
    ul.appendChild(li);
  });
  root.appendChild(ul);
}

// eslint-disable-next-line no-unused-vars
async function fetchArchetypes() {
  const res = await fetch('/assets/archetypes.json');
  return res.json();
}

function prefillTeamEditor() {
  const form = document.querySelector('form[action*="/edit/team"]');
  if (!form) {
    return;
  }
  const id = decodeURIComponent(window.location.pathname.split('/').slice(-3, -2)[0] || 'new');
  if (id === 'new') {
    return;
  }
  const scenario = load(id);
  if (scenario === null) {
    return;
  }
  const fields = form.querySelectorAll('input[name], select[name]');
  fields.forEach((field) => {
    const name = field.getAttribute('name');
    if (!name) {
      return;
    }
    const value = resolveField(scenario, name);
    if (value !== undefined) {
      Object.assign(field, { value: String(value) });
    }
  });
}

async function startMatch() {
  const id = decodeURIComponent(window.location.pathname.split('/').slice(-3, -2)[0] || 'new');
  if (id === 'new') {
    return;
  }
  const scenario = load(id);
  if (scenario === null) {
    return;
  }
  const csrf = getCsrfToken();
  const res = await fetch(`/scenarios/${encodeURIComponent(id)}/start`, {
    method: 'POST',
    headers: {
      'Content-Type': 'application/json',
      'X-CSRF-Token': csrf,
    },
    body: JSON.stringify(scenario),
  });
  if (!res.ok) {
    // eslint-disable-next-line no-alert
    alert(`Start match failed: HTTP ${res.status}`);
    return;
  }
  const data = await res.json();
  if (data.match) {
    setCurrentMatch(data.match);
    window.location.href = '/';
  } else {
    // eslint-disable-next-line no-alert
    alert(`Start match failed: ${data.errors ? data.errors.join(', ') : 'unknown'}`);
  }
}

window.bfStorage = {
  load,
  save,
  delete: remove,
  listAll,
  currentMatch,
  setCurrentMatch,
  removeCurrentMatch,
};

document.addEventListener('DOMContentLoaded', () => {
  populateRecentScenarios();
  prefillTeamEditor();
  const startBtn = document.getElementById('bf-start-match');
  if (startBtn) {
    startBtn.addEventListener('click', (event) => {
      event.preventDefault();
      startMatch();
    });
  }
});