function createWeekPlan({fetchJson,localDate,timeZone}={}) {
  let week={revision:0,timezone:null,days:[]};
  let lastConflict=null;
  const cloneDay=day=>({
    plan_date:day.plan_date,ids:[...(day.ids||[])],capacity_minutes:day.capacity_minutes??null,
    estimates:{...(day.estimates||{})},
  });
  const state=()=>({revision:week.revision,timezone:week.timezone,days:week.days.map(cloneDay)});
  function adopt(value) {
    if(!Number.isInteger(value?.revision)||!Array.isArray(value?.days)) return false;
    week={revision:value.revision,timezone:value.timezone||null,days:value.days.map(cloneDay)
      .sort((left,right)=>left.plan_date.localeCompare(right.plan_date))};
    lastConflict=null;
    return state();
  }
  function addDays(value, amount) {
    const [year,month,day]=value.split('-').map(Number);
    return new Date(Date.UTC(year,month-1,day+amount)).toISOString().slice(0,10);
  }
  function dates() {
    return Array.from({length:7},(_,index)=>{
      const date=addDays(localDate(),index+1);
      const parsed=new Date(date+'T12:00:00Z');
      return {date,label:new Intl.DateTimeFormat('en',{weekday:'short',month:'short',day:'numeric',timeZone:'UTC'}).format(parsed)};
    });
  }
  function day(planDate) {
    const found=week.days.find(item=>item.plan_date===planDate);
    return found?cloneDay(found):{plan_date:planDate,ids:[],capacity_minutes:null,estimates:{}};
  }
  async function load() { return adopt(await fetchJson('api/v1/week')); }
  async function saveDay(planDate, value) {
    const local={revision:week.revision,timezone:timeZone(),days:week.days
      .filter(item=>item.plan_date!==planDate).concat([{
        plan_date:planDate,ids:[...(value.ids||[])],capacity_minutes:value.capacity_minutes??null,
        estimates:{...(value.estimates||{})},
      }]).sort((left,right)=>left.plan_date.localeCompare(right.plan_date))};
    const body={base_revision:local.revision,timezone:local.timezone,days:local.days};
    try {
      return adopt(await fetchJson('api/v1/week',{method:'PUT',headers:{'Content-Type':'application/json'},body:JSON.stringify(body)}));
    } catch(error) {
      if(error?.status===409) {
        const remote=await fetchJson('api/v1/week');
        lastConflict={local,remote:{revision:remote.revision,timezone:remote.timezone,days:remote.days.map(cloneDay)}};
      }
      throw error;
    }
  }
  function conflict() {
    return lastConflict?{
      local:{...lastConflict.local,days:lastConflict.local.days.map(cloneDay)},
      remote:{...lastConflict.remote,days:lastConflict.remote.days.map(cloneDay)},
    }:null;
  }
  async function promote(todayRevision) {
    const due=week.days.find(item=>item.plan_date<=localDate()&&item.ids.length);
    if(!due) return false;
    return fetchJson('api/v1/week/promote',{method:'POST',headers:{'Content-Type':'application/json'},body:JSON.stringify({
      promotion_id:`week-${due.plan_date}-r${week.revision}`,week_revision:week.revision,
      plan_date:due.plan_date,today_revision:todayRevision,
    })});
  }
  function summary() {
    const planned=week.days.filter(item=>item.ids.length);
    const items=planned.reduce((total,item)=>total+item.ids.length,0);
    return planned.length?`${items} item${items===1?'':'s'} across ${planned.length} day${planned.length===1?'':'s'}`:'Nothing planned';
  }
  return {adopt,state,dates,day,load,saveDay,conflict,promote,summary};
}
function createWeekPlanWorkflow({controller,qs,getLogin,openPlanner,escapeHtml,escapeAttribute,
  todayWork,refresh,warm}={}) {
  let selectedDate=null;
  function renderDates() {
    const root=qs('#week-plan-dates');
    root.hidden=!selectedDate;
    if(!selectedDate)return;
    root.innerHTML=controller.dates().map(item=>'<button type="button" data-week-plan-date="'+
      escapeAttribute(item.date)+'"'+(item.date===selectedDate?' aria-current="date"':'')+'><strong>'+escapeHtml(item.label)+
      '</strong><small>'+escapeHtml(controller.day(item.date).ids.length+' planned')+'</small></button>').join('');
    root.querySelectorAll('[data-week-plan-date]').forEach(button=>button.addEventListener('click',()=>{
      selectedDate=button.dataset.weekPlanDate;renderDates();openPlanner(null,false);
    }));
  }
  async function open(trigger) {
    if(!getLogin()){qs('#my-work-action-status').textContent='Planning is unavailable until your operator identity is restored.';return false;}
    trigger.disabled=true;qs('#mobile-week-summary').textContent='Loading Week Ahead…';
    try{await controller.load();selectedDate=controller.dates()[0].date;qs('#mobile-week-summary').textContent=controller.summary();openPlanner(trigger);return true;}
    catch(error){qs('#mobile-week-summary').textContent='Unavailable · tap to retry';qs('#my-work-action-status').textContent=(error.message||'Week Ahead is unavailable.')+' Retry when connected.';return false;}
    finally{trigger.disabled=false;}
  }
  function save(plan){
    const date=selectedDate,normalized=Array.isArray(plan)?{ids:plan,capacity_minutes:null,estimates:{}}:plan;
    controller.saveDay(date,normalized).then(()=>{qs('#mobile-week-summary').textContent=controller.summary();qs('#my-work-action-status').textContent=(normalized.ids.length?'Week Ahead saved for ':'Week Ahead cleared for ')+date+'.';})
      .catch(error=>{qs('#mobile-week-summary').textContent=controller.conflict()?'Conflict · review required':'Unavailable · tap to retry';qs('#my-work-action-status').textContent=controller.conflict()?'Another device changed Week Ahead. Both versions are preserved; reopen Week Ahead to review.':(error.message||'Week Ahead could not be saved.')+' Retry when connected.';});
    return true;
  }
  async function promote(plan){
    try{await controller.load();const promoted=await controller.promote(plan.revision);if(!promoted)return false;todayWork.replace(promoted.ids);todayWork.replacePlanning({capacity_minutes:promoted.capacity_minutes??null,estimates:promoted.estimates||{}});refresh();warm();qs('#mobile-week-summary').textContent=controller.summary();qs('#my-work-action-status').textContent='Your saved Week Ahead plan is now Today.';return true;}
    catch(error){qs('#my-work-action-status').textContent=(error.message||'Week Ahead needs review before promotion.')+' Open Week Ahead to review.';return false;}
  }
  return {open,save,promote,renderDates,active:()=>Boolean(selectedDate),selectedDate:()=>selectedDate,
    day:()=>selectedDate?controller.day(selectedDate):null,
    copy:()=>selectedDate?{title:'Plan Week Ahead',heading:selectedDate+', in order',available:'Available this day',build:'Build this day'}:null,
    clear(){selectedDate=null;renderDates();}};
}
if(typeof module!=='undefined'&&module.exports)module.exports=createWeekPlan;