// event-manager.js — Event creation, editing, drag/drop, and selection logic
import {
  toLocalString,
  fromLocalString,
  daysInclusive,
  addDaysStr,
  formatDateRange
} from './date-utils.js'

export class EventManager {
  constructor(calendar) {
    this.calendar = calendar
    this.events = new Map() // Map of date strings to arrays of events
    this.eventIdCounter = 1
    
    // Selection state
    this.selStart = null
    this.selEnd = null
    this.isDragging = false
    this.dragAnchor = null
    
    // Event drag state
    this.dragEventState = null
    this.dragPreview = null
    this.justDragged = false
    this._eventDragMoved = false
    this._installedEventDrag = false
    
    this.setupEventDialog()
  }

  // -------- Selection Logic --------
  
  clampRange(anchorStr, otherStr) {
    if (this.calendar.config.select_days <= 1) return [otherStr, otherStr]
    const limit = this.calendar.config.select_days
    const forward = fromLocalString(otherStr) >= fromLocalString(anchorStr)
    const span = daysInclusive(anchorStr, otherStr)
    if (span <= limit) {
      const a = [anchorStr, otherStr].sort()
      return [a[0], a[1]]
    }
    if (forward) return [anchorStr, addDaysStr(anchorStr, limit - 1)]
    return [addDaysStr(anchorStr, -(limit - 1)), anchorStr]
  }

  setSelection(aStr, bStr) {
    const [start, end] = this.clampRange(aStr, bStr)
    this.selStart = start
    this.selEnd = end
    this.applySelectionToVisible()
    this.calendar.selectedDateInput.value = formatDateRange(fromLocalString(start), fromLocalString(end))
  }

  clearSelection() {
    this.selStart = null
    this.selEnd = null
    for (const [, weekEl] of this.calendar.visibleWeeks) {
      weekEl.querySelectorAll('.cell.selected').forEach(c => c.classList.remove('selected'))
    }
    this.calendar.selectedDateInput.value = ''
  }

  applySelectionToVisible() {
    for (const [, weekEl] of this.calendar.visibleWeeks) {
      const cells = weekEl.querySelectorAll('.cell[data-date]')
      for (const cell of cells) {
        if (!this.selStart || !this.selEnd) {
          cell.classList.remove('selected')
          continue
        }
        const ds = cell.dataset.date
        const inRange = ds >= this.selStart && ds <= this.selEnd
        cell.classList.toggle('selected', inRange)
      }
    }
  }

  startDrag(dateStr) {
    if (this.calendar.config.select_days === 0) return
    this.isDragging = true
    this.dragAnchor = dateStr
    this.setSelection(dateStr, dateStr)
  }

  updateDrag(dateStr) {
    if (!this.isDragging) return
    this.setSelection(this.dragAnchor, dateStr)
    document.body.style.cursor = 'default'
  }

  endDrag(dateStr) {
    if (!this.isDragging) return
    this.isDragging = false
    this.setSelection(this.dragAnchor, dateStr)
    document.body.style.cursor = 'default'
    if (this.selStart && this.selEnd) {
      setTimeout(() => this.showEventDialog('create'), 50)
    }
  }

  // -------- Event Management --------

  createEvent(eventData) {
    const singleDay = eventData.startDate === eventData.endDate
    const event = {
      id: this.eventIdCounter++,
      title: eventData.title,
      startDate: eventData.startDate,
      endDate: eventData.endDate,
      colorId: eventData.colorId ?? this.selectEventColorId(eventData.startDate, eventData.endDate),
      startTime: singleDay ? (eventData.startTime || '09:00') : null,
      durationMinutes: singleDay ? (eventData.durationMinutes || 60) : null
    }

    const startDate = new Date(fromLocalString(event.startDate))
    const endDate = new Date(fromLocalString(event.endDate))

    for (let d = new Date(startDate); d <= endDate; d.setDate(d.getDate() + 1)) {
      const dateStr = toLocalString(d)
      if (!this.events.has(dateStr)) this.events.set(dateStr, [])
      this.events.get(dateStr).push({ ...event, isSpanning: startDate < endDate })
    }

    this.calendar.forceUpdateVisibleWeeks()
  }

  createEventWithRepeat(eventData) {
    const { repeat, repeatCount, ...baseEventData } = eventData
    
    if (repeat === 'none') {
      // Single event
      this.createEvent(baseEventData)
      return
    }

    // Calculate dates for repeating events
    const startDate = new Date(fromLocalString(baseEventData.startDate))
    const endDate = new Date(fromLocalString(baseEventData.endDate))
    const spanDays = Math.floor((endDate - startDate) / (24 * 60 * 60 * 1000))
    
    const maxOccurrences = repeatCount === 'unlimited' ? 104 : parseInt(repeatCount, 10) // Cap unlimited at ~2 years
    const dates = []
    
    for (let i = 0; i < maxOccurrences; i++) {
      const currentStart = new Date(startDate)
      
      switch (repeat) {
        case 'daily':
          currentStart.setDate(startDate.getDate() + i)
          break
        case 'weekly':
          currentStart.setDate(startDate.getDate() + i * 7)
          break
        case 'biweekly':
          currentStart.setDate(startDate.getDate() + i * 14)
          break
        case 'monthly':
          currentStart.setMonth(startDate.getMonth() + i)
          break
        case 'yearly':
          currentStart.setFullYear(startDate.getFullYear() + i)
          break
      }
      
      const currentEnd = new Date(currentStart)
      currentEnd.setDate(currentStart.getDate() + spanDays)
      
      dates.push({
        startDate: toLocalString(currentStart),
        endDate: toLocalString(currentEnd)
      })
    }
    
    // Create events for all dates
    dates.forEach(({ startDate, endDate }) => {
      this.createEvent({
        ...baseEventData,
        startDate,
        endDate
      })
    })
  }

  getEventById(id) {
    for (const [, list] of this.events) {
      const found = list.find(e => e.id === id)
      if (found) return found
    }
    return null
  }

  selectEventColorId(startDateStr, endDateStr) {
    const colorCounts = [0, 0, 0, 0, 0, 0, 0, 0]
    const startDate = new Date(fromLocalString(startDateStr))
    const endDate = new Date(fromLocalString(endDateStr))

    for (let d = new Date(startDate); d <= endDate; d.setDate(d.getDate() + 1)) {
      const dateStr = toLocalString(d)
      const dayEvents = this.events.get(dateStr) || []
      for (const event of dayEvents) {
        if (event.colorId >= 0 && event.colorId < 8) {
          colorCounts[event.colorId]++
        }
      }
    }

    let minCount = colorCounts[0]
    let selectedColor = 0

    for (let colorId = 1; colorId < 8; colorId++) {
      if (colorCounts[colorId] < minCount) {
        minCount = colorCounts[colorId]
        selectedColor = colorId
      }
    }

    return selectedColor
  }

  applyEventEdit(eventId, data) {
    const current = this.getEventById(eventId)
    if (!current) return
    const newStart = data.startDate || current.startDate
    const newEnd = data.endDate || current.endDate
    const datesChanged = (newStart !== current.startDate) || (newEnd !== current.endDate)
    if (datesChanged) {
      const multi = daysInclusive(newStart, newEnd) > 1
      const payload = {
        ...current,
        title: data.title.trim(),
        colorId: data.colorId,
        startDate: newStart,
        endDate: newEnd,
        startTime: multi ? null : (data.startTime ?? current.startTime),
        durationMinutes: multi ? null : (data.duration ?? current.durationMinutes)
      }
      this.updateEventDatesAndReindex(eventId, payload)
      this.calendar.forceUpdateVisibleWeeks()
      return
    }
    // No date change: update in place across instances
    for (const [, list] of this.events) {
      for (let i = 0; i < list.length; i++) {
        if (list[i].id === eventId) {
          const isMulti = list[i].startDate !== list[i].endDate
          list[i] = {
            ...list[i],
            title: data.title.trim(),
            colorId: data.colorId,
            startTime: isMulti ? null : data.startTime,
            durationMinutes: isMulti ? null : data.duration
          }
        }
      }
    }
    this.calendar.forceUpdateVisibleWeeks()
  }

  updateEventDatesAndReindex(eventId, updated) {
    // Remove old instances
    for (const [date, list] of this.events) {
      const idx = list.findIndex(e => e.id === eventId)
      if (idx !== -1) list.splice(idx, 1)
      if (list.length === 0) this.events.delete(date)
    }
    // Re-add across new range
    const start = new Date(fromLocalString(updated.startDate))
    const end = new Date(fromLocalString(updated.endDate))
    const base = {
      id: updated.id,
      title: updated.title,
      colorId: updated.colorId,
      startDate: updated.startDate,
      endDate: updated.endDate,
      startTime: updated.startTime,
      durationMinutes: updated.durationMinutes
    }
    for (let d = new Date(start); d <= end; d.setDate(d.getDate() + 1)) {
      const ds = toLocalString(d)
      if (!this.events.has(ds)) this.events.set(ds, [])
      this.events.get(ds).push({ ...base, isSpanning: start < end })
    }
  }

  // -------- Event Dialog --------

  setupEventDialog() {
    const tpl = document.createElement('template')
    tpl.innerHTML = `
      <div class="ec-modal-backdrop" part="backdrop" hidden>
        <div class="ec-modal" role="dialog" aria-modal="true" aria-labelledby="ec-modal-title">
          <form class="ec-form" novalidate>
            <header class="ec-header">
              <h2 id="ec-modal-title">Event</h2>
            </header>
            <div class="ec-body">
              <label class="ec-field">
                <span>Title</span>
                <input type="text" name="title" autocomplete="off" required />
              </label>
              <label class="ec-field">
                <span>Repeat</span>
                <select name="repeat">
                  <option value="none">No repeat</option>
                  <option value="daily">Daily</option>
                  <option value="weekly">Weekly</option>
                  <option value="biweekly">Every 2 weeks</option>
                  <option value="monthly">Monthly</option>
                  <option value="yearly">Yearly</option>
                </select>
              </label>
              <div class="ec-repeat-count-row" style="display: none;">
                <label class="ec-field">
                  <span>Number of occurrences</span>
                  <select name="repeatCount">
                    <option value="2">2 times</option>
                    <option value="3">3 times</option>
                    <option value="4">4 times</option>
                    <option value="5">5 times</option>
                    <option value="10">10 times</option>
                    <option value="52">52 times (1 year)</option>
                    <option value="unlimited">Unlimited</option>
                  </select>
                </label>
              </div>
              <div class="ec-color-swatches">
                ${Array.from({ length: 8 }, (_, i) => `
                    <input class="swatch event-color-${i}" type="radio" name="colorId" value="${i}">
                `).join('')}
              </div>
            </div>
            <footer class="ec-footer">
              <button type="button" class="ec-btn" data-action="delete">Delete</button>
              <button type="submit" class="ec-btn primary">Save</button>
            </footer>
          </form>
        </div>
      </div>`

    document.body.appendChild(tpl.content)
    this.eventModal = document.querySelector('.ec-modal-backdrop')
    this.eventForm = this.eventModal.querySelector('form.ec-form')
    this.eventTitleInput = this.eventForm.elements['title']
    this.eventRepeatInput = this.eventForm.elements['repeat']
    this.eventRepeatCountInput = this.eventForm.elements['repeatCount']
    this.eventRepeatCountRow = this.eventForm.querySelector('.ec-repeat-count-row')
    this.eventColorInputs = Array.from(this.eventForm.querySelectorAll('input[name="colorId"]'))

    // Repeat change toggles repeat count visibility
    this.eventRepeatInput.addEventListener('change', () => {
      const showRepeatCount = this.eventRepeatInput.value !== 'none'
      this.eventRepeatCountRow.style.display = showRepeatCount ? 'block' : 'none'
    })

    // Color selection visual state
    this.eventColorInputs.forEach(radio => {
      radio.addEventListener('change', () => {
        const swatches = this.eventForm.querySelectorAll('.ec-color-swatches .swatch')
        swatches.forEach(s => s.classList.toggle('selected', s.checked))
      })
    })

    this.eventForm.addEventListener('submit', e => {
      e.preventDefault()
      const data = this.readEventForm()
      if (!data.title.trim()) return
      
      if (this._dialogMode === 'create') {
        this.createEventWithRepeat({
          title: data.title.trim(),
          startDate: this.selStart,
          endDate: this.selEnd,
          colorId: data.colorId,
          repeat: data.repeat,
          repeatCount: data.repeatCount
        })
        this.clearSelection()
      } else if (this._dialogMode === 'edit' && this._editingEventId != null) {
        this.applyEventEdit(this._editingEventId, {
          title: data.title.trim(),
          colorId: data.colorId,
          repeat: data.repeat,
          repeatCount: data.repeatCount
        })
      }
      this.hideEventDialog()
    })

    this.eventForm.querySelector('[data-action="delete"]').addEventListener('click', () => {
      if (this._dialogMode === 'edit' && this._editingEventId) {
        // Find and remove the event from ALL dates it spans across
        const datesToCleanup = []
        for (const [dateStr, eventList] of this.events) {
          const eventIndex = eventList.findIndex(event => event.id === this._editingEventId)
          if (eventIndex !== -1) {
            eventList.splice(eventIndex, 1)
            // Mark date for cleanup if empty
            if (eventList.length === 0) {
              datesToCleanup.push(dateStr)
            }
          }
        }
        // Clean up empty date entries
        datesToCleanup.forEach(dateStr => this.events.delete(dateStr))
        this.calendar.forceUpdateVisibleWeeks()
      }
      this.hideEventDialog()
      if (this._dialogMode === 'create') this.clearSelection()
    })

    this.eventModal.addEventListener('click', e => {
      if (e.target === this.eventModal) this.hideEventDialog()
    })

    document.addEventListener('keydown', e => {
      if (this.eventModal.hidden) return
      if (e.key === 'Escape') {
        this.hideEventDialog()
        if (this._dialogMode === 'create') this.clearSelection()
      }
    })
  }

  showEventDialog(mode, opts = {}) {
    this._dialogMode = mode
    this._editingEventId = null

    if (mode === 'create') {
      this.eventTitleInput.value = ''
      this.eventRepeatInput.value = 'none'
      this.eventRepeatCountInput.value = '5'
      this.eventRepeatCountRow.style.display = 'none'
      const suggested = this.selectEventColorId(this.selStart, this.selEnd)
      this.eventColorInputs.forEach(r => r.checked = Number(r.value) === suggested)
    } else if (mode === 'edit') {
      const ev = this.getEventById(opts.id)
      if (!ev) return
      this._editingEventId = ev.id
      this.eventTitleInput.value = ev.title || ''
      this.eventRepeatInput.value = ev.repeat || 'none'
      this.eventRepeatCountInput.value = ev.repeatCount || '5'
      this.eventRepeatCountRow.style.display = (ev.repeat && ev.repeat !== 'none') ? 'block' : 'none'
      this.eventColorInputs.forEach(r => r.checked = Number(r.value) === (ev.colorId ?? 0))
    }
    this.eventModal.hidden = false
    setTimeout(() => this.eventTitleInput.focus(), 0)
  }

  hideEventDialog() {
    this.eventModal.hidden = true
  }

  readEventForm() {
    const colorId = Number(this.eventForm.querySelector('input[name="colorId"]:checked')?.value ?? 0)
    return {
      title: this.eventTitleInput.value,
      repeat: this.eventRepeatInput.value,
      repeatCount: this.eventRepeatCountInput.value,
      colorId
    }
  }

  // -------- Event Drag & Drop --------

  installGlobalEventDragHandlers() {
    if (this._installedEventDrag) return
    this._installedEventDrag = true
    this._onMouseMoveEventDrag = e => this.onEventDragMove(e)
    this._onMouseUpEventDrag = e => this.onEventDragEnd(e)
    document.addEventListener('mousemove', this._onMouseMoveEventDrag)
    document.addEventListener('mouseup', this._onMouseUpEventDrag)
    
    this._onTouchMoveEventDrag = e => this.onEventDragMove(e)
    this._onTouchEndEventDrag = e => this.onEventDragEnd(e)
    document.addEventListener('touchmove', this._onTouchMoveEventDrag, { passive: false })
    document.addEventListener('touchend', this._onTouchEndEventDrag)
    
    this._onPointerMoveEventDrag = e => this.onEventDragMove(e)
    this._onPointerUpEventDrag = e => this.onEventDragEnd(e)
    this._onPointerCancelEventDrag = e => this.onEventDragEnd(e)
    window.addEventListener('pointermove', this._onPointerMoveEventDrag)
    window.addEventListener('pointerup', this._onPointerUpEventDrag)
    window.addEventListener('pointercancel', this._onPointerCancelEventDrag)
    
    this._onWindowMouseUpEventDrag = e => this.onEventDragEnd(e)
    this._onWindowBlurEventDrag = () => this.onEventDragEnd()
    window.addEventListener('mouseup', this._onWindowMouseUpEventDrag)
    window.addEventListener('blur', this._onWindowBlurEventDrag)
  }

  removeGlobalEventDragHandlers() {
    if (!this._installedEventDrag) return
    document.removeEventListener('mousemove', this._onMouseMoveEventDrag)
    document.removeEventListener('mouseup', this._onMouseUpEventDrag)
    document.removeEventListener('touchmove', this._onTouchMoveEventDrag)
    document.removeEventListener('touchend', this._onTouchEndEventDrag)
    window.removeEventListener('pointermove', this._onPointerMoveEventDrag)
    window.removeEventListener('pointerup', this._onPointerUpEventDrag)
    window.removeEventListener('pointercancel', this._onPointerCancelEventDrag)
    window.removeEventListener('mouseup', this._onWindowMouseUpEventDrag)
    window.removeEventListener('blur', this._onWindowBlurEventDrag)
    this._installedEventDrag = false
  }

  onEventDragMove(e) {
    if (!this.dragEventState) return
    if (this.dragEventState.usingPointer && !(e && e.type && e.type.startsWith('pointer'))) return
    
    const pt = e.touches ? e.touches[0] : e
    
    // Check if we've moved far enough to consider this a real drag
    if (!this._eventDragMoved) {
      const dx = pt.clientX - this.dragEventState.pointerStartX
      const dy = pt.clientY - this.dragEventState.pointerStartY
      const distance = Math.sqrt(dx * dx + dy * dy)
      const minDragDistance = 5 // pixels
      
      if (distance < minDragDistance) {
        return // Don't start dragging yet
      }
      // Only prevent default when we actually start dragging
      if (e && e.cancelable) e.preventDefault()
      this._eventDragMoved = true
    } else {
      // Already dragging, continue to prevent default
      if (e && e.cancelable) e.preventDefault()
    }
    
    const hit = pt ? this.calendar.getDateUnderPointer(pt.clientX, pt.clientY) : null
    if (hit && hit.date) {
      const [s, en] = this.computeTentativeRangeFromPointer(hit.date)
      this.dragPreview = { id: this.dragEventState.id, startDate: s, endDate: en }
    } else {
      this.dragPreview = null
    }
    this.calendar.forceUpdateVisibleWeeks()
  }

  onEventDragEnd(e) {
    if (!this.dragEventState) return
    if (this.dragEventState.usingPointer && e && !(e.type && e.type.startsWith('pointer'))) {
      return
    }
    
    const st = this.dragEventState
    
    let startDateStr = this.dragPreview?.startDate
    let endDateStr = this.dragPreview?.endDate
    
    if (!startDateStr || !endDateStr) {
      const getPoint = ev => (ev && ev.changedTouches && ev.changedTouches[0]) ? ev.changedTouches[0] : (ev && ev.touches ? ev.touches[0] : ev)
      const pt = getPoint(e)
      const drop = pt ? this.calendar.getDateUnderPointer(pt.clientX, pt.clientY) : null
      if (drop && drop.date) {
        const pair = this.computeTentativeRangeFromPointer(drop.date)
        startDateStr = pair[0]
        endDateStr = pair[1]
      } else {
        startDateStr = st.startDate
        endDateStr = st.endDate
      }
    }

    const ev = this.getEventById(st.id)
    if (ev) {
      const updated = { ...ev }
      if (st.mode === 'move') {
        const spanDays = daysInclusive(ev.startDate, ev.endDate)
        updated.startDate = startDateStr
        updated.endDate = addDaysStr(startDateStr, spanDays - 1)
      } else {
        if (startDateStr <= endDateStr) {
          updated.startDate = startDateStr
          updated.endDate = endDateStr
        }
      }

      let [ns, ne] = this.normalizeDateOrder(updated.startDate, updated.endDate)
      updated.startDate = ns
      updated.endDate = ne
      const multi = daysInclusive(updated.startDate, updated.endDate) > 1
      if (multi) {
        updated.startTime = null
        updated.durationMinutes = null
      } else {
        if (!updated.startTime) updated.startTime = '09:00'
        if (!updated.durationMinutes) updated.durationMinutes = 60
      }

      this.updateEventDatesAndReindex(ev.id, updated)
    }

    try {
      if (st.usingPointer && st.element && st.element.releasePointerCapture && e && e.pointerId != null) {
        st.element.releasePointerCapture(e.pointerId)
      }
    } catch {}
    
    this.dragEventState = null
    
    // Only set justDragged if we actually moved and dragged
    this.justDragged = !!this._eventDragMoved
    
    this._eventDragMoved = false
    this.removeGlobalEventDragHandlers()
    
    // Only update visible weeks if we actually dragged
    if (this.justDragged) {
      this.calendar.forceUpdateVisibleWeeks()
    }
    
    // Clear justDragged flag after a short delay to allow click events to process
    if (this.justDragged) {
      setTimeout(() => { 
        this.justDragged = false 
      }, 100)
    }
    this.dragPreview = null
  }

  computeTentativeRangeFromPointer(dropDateStr) {
    const st = this.dragEventState
    if (!st) return [null, null]
    const anchorOffset = st.anchorOffset || 0
    const spanDays = st.originSpanDays || daysInclusive(st.startDate, st.endDate)
    let startStr = st.startDate
    let endStr = st.endDate
    if (st.mode === 'move') {
      startStr = addDaysStr(dropDateStr, -anchorOffset)
      endStr = addDaysStr(startStr, spanDays - 1)
    } else if (st.mode === 'resize-left') {
      startStr = dropDateStr
      endStr = st.originalEndDate || st.endDate
    } else if (st.mode === 'resize-right') {
      startStr = st.originalStartDate || st.startDate
      endStr = dropDateStr
    }
    const [ns, ne] = this.normalizeDateOrder(startStr, endStr)
    return [ns, ne]
  }

  normalizeDateOrder(aStr, bStr) {
    if (!aStr) return [bStr, bStr]
    if (!bStr) return [aStr, aStr]
    return aStr <= bStr ? [aStr, bStr] : [bStr, aStr]
  }

  addEventsToWeek(weekEl) {
    const daysGrid = weekEl._daysGrid || weekEl.querySelector('.days-grid')
    const overlay = weekEl._overlay || weekEl.querySelector('.week-overlay')
    if (!daysGrid || !overlay) return

    const cells = Array.from(daysGrid.querySelectorAll('.cell[data-date]'))

    while (overlay.firstChild) overlay.removeChild(overlay.firstChild)

    const weekEvents = new Map()
    for (const cell of cells) {
      const dateStr = cell.dataset.date
      const events = this.events.get(dateStr) || []
      for (const ev of events) {
        if (!weekEvents.has(ev.id)) {
          weekEvents.set(ev.id, {
            ...ev,
            startDateInWeek: dateStr,
            endDateInWeek: dateStr,
            startIdx: cells.indexOf(cell),
            endIdx: cells.indexOf(cell)
          })
        } else {
          const w = weekEvents.get(ev.id)
          w.endDateInWeek = dateStr
          w.endIdx = cells.indexOf(cell)
        }
      }
    }

    // If dragging, hide the original of the dragged event and inject preview if it intersects this week
    if (this.dragPreview && this.dragPreview.id != null) {
      const pv = this.dragPreview
      // Remove original entries of the dragged event for this week to prevent ghosts
      if (weekEvents.has(pv.id)) weekEvents.delete(pv.id)
      // Determine week range
      const weekStart = cells[0]?.dataset?.date
      const weekEnd = cells[cells.length - 1]?.dataset?.date
      if (weekStart && weekEnd) {
        const s = pv.startDate
        const e = pv.endDate
        // Intersect preview with this week
        const startInWeek = s <= weekEnd && e >= weekStart ? (s < weekStart ? weekStart : s) : null
        const endInWeek = s <= weekEnd && e >= weekStart ? (e > weekEnd ? weekEnd : e) : null
        if (startInWeek && endInWeek) {
          // Compute indices
          let sIdx = cells.findIndex(c => c.dataset.date === startInWeek)
          if (sIdx === -1) sIdx = cells.findIndex(c => c.dataset.date > startInWeek)
          if (sIdx === -1) sIdx = 0
          let eIdx = -1
          for (let i = 0; i < cells.length; i++) {
            if (cells[i].dataset.date <= endInWeek) eIdx = i
          }
          if (eIdx === -1) eIdx = cells.length - 1

          // Build/override entry
          const baseEv = this.getEventById(pv.id)
          if (baseEv) {
            const entry = {
              ...baseEv,
              startDateInWeek: startInWeek,
              endDateInWeek: endInWeek,
              startIdx: sIdx,
              endIdx: eIdx
            }
            weekEvents.set(pv.id, entry)
          }
        }
      }
    }

    const timeToMin = t => {
      if (typeof t !== 'string') return 1e9
      const m = t.match(/^(\d{2}):(\d{2})/)
      if (!m) return 1e9
      return Number(m[1]) * 60 + Number(m[2])
    }

    const spans = Array.from(weekEvents.values()).sort((a, b) => {
      if (a.startIdx !== b.startIdx) return a.startIdx - b.startIdx
      // Prefer longer spans to be placed first for packing
      const aLen = a.endIdx - a.startIdx
      const bLen = b.endIdx - b.startIdx
      if (aLen !== bLen) return bLen - aLen
      // Within the same day and same span length, order by start time
      const at = timeToMin(a.startTime)
      const bt = timeToMin(b.startTime)
      if (at !== bt) return at - bt
      // Stable fallback by id
      return (a.id || 0) - (b.id || 0)
    })

    const rowsLastEnd = []
    for (const w of spans) {
      let placedRow = 0
      while (placedRow < rowsLastEnd.length && !(w.startIdx > rowsLastEnd[placedRow])) placedRow++
      if (placedRow === rowsLastEnd.length) rowsLastEnd.push(-1)
      rowsLastEnd[placedRow] = w.endIdx
      w._row = placedRow + 1
    }

    const numRows = Math.max(1, rowsLastEnd.length)

    // Decide between "comfortable" layout (with gaps, not stretched)
    // and "compressed" layout (fractional rows, no gaps) based on fit.
    const cs = getComputedStyle(overlay)
    const overlayHeight = overlay.getBoundingClientRect().height
    const marginTopPx = parseFloat(cs.marginTop) || 0
    const available = Math.max(0, overlayHeight - marginTopPx)
    const baseEm = parseFloat(cs.fontSize) || 16
    const rowPx = 1.2 * baseEm      // preferred row height ~ 1.2em
    const gapPx = 0.2 * baseEm      // preferred gap ~ .2em
    const needed = numRows * rowPx + (numRows - 1) * gapPx

    if (needed <= available) {
      // Comfortable: keep gaps and do not stretch rows to fill
      overlay.style.gridTemplateRows = `repeat(${numRows}, ${rowPx}px)`
      overlay.style.rowGap = `${gapPx}px`
    } else {
      // Compressed: use fractional rows so everything fits; remove gaps
      overlay.style.gridTemplateRows = `repeat(${numRows}, 1fr)`
      overlay.style.rowGap = '0'
    }

    // Create the spans
    for (const w of spans) this.createOverlaySpan(overlay, w, weekEl)
  }

  createOverlaySpan(overlay, w, weekEl) {
    const span = document.createElement('div')
    span.className = `event-span event-color-${w.colorId}`
    span.style.gridColumn = `${w.startIdx + 1} / ${w.endIdx + 2}`
    span.style.gridRow = `${w._row}`
    span.textContent = w.title
    span.title = `${w.title} (${w.startDate === w.endDate ? w.startDate : w.startDate + ' - ' + w.endDate})`
    span.dataset.eventId = String(w.id)
    if (this.dragEventState && this.dragEventState.id === w.id) span.classList.add('dragging')

    // Click opens edit if not dragging
    span.addEventListener('click', e => {
      e.stopPropagation()
      
      // Only block if we actually dragged (moved the mouse)
      if (this.justDragged) return
      
      this.showEventDialog('edit', { id: w.id })
    })

    // Add resize handles
    const left = document.createElement('div')
    left.className = 'resize-handle left'
    const right = document.createElement('div')
    right.className = 'resize-handle right'
    span.appendChild(left)
    span.appendChild(right)

    // Pointer down handlers
    const onPointerDown = (mode, ev) => {
      // Prevent duplicate handling if we already have a drag state
      if (this.dragEventState) return
      
      // Don't prevent default immediately - let click events through
      ev.stopPropagation()
      const point = ev.touches ? ev.touches[0] : ev
      const hitAtStart = this.calendar.getDateUnderPointer(point.clientX, point.clientY)
      this.dragEventState = {
        mode,
        id: w.id,
        originWeek: weekEl,
        originStartIdx: w.startIdx,
        originEndIdx: w.endIdx,
        pointerStartX: point.clientX,
        pointerStartY: point.clientY,
        startDate: w.startDate,
        endDate: w.endDate,
        usingPointer: ev.type && ev.type.startsWith('pointer')
      }
      // compute anchor offset within the event based on where the pointer is
      const spanDays = daysInclusive(w.startDate, w.endDate)
      let anchorOffset = 0
      if (hitAtStart && hitAtStart.date) {
        const anchorDate = hitAtStart.date
        // clamp anchorDate to within event span
        if (anchorDate < w.startDate) anchorOffset = 0
        else if (anchorDate > w.endDate) anchorOffset = spanDays - 1
        else anchorOffset = daysInclusive(w.startDate, anchorDate) - 1
      }
      this.dragEventState.anchorOffset = anchorOffset
      this.dragEventState.originSpanDays = spanDays
      this.dragEventState.originalStartDate = w.startDate
      this.dragEventState.originalEndDate = w.endDate
      // capture pointer to ensure we receive the up even if cursor leaves element
      if (this.dragEventState.usingPointer && span.setPointerCapture && ev.pointerId != null) {
        try { span.setPointerCapture(ev.pointerId) } catch {}
      }
      this.dragEventState.element = span
      this.dragEventState.currentOverlay = overlay
      this._eventDragMoved = false
      span.classList.add('dragging')
      this.installGlobalEventDragHandlers()
    }
    
    // Use pointer events (supported by all modern browsers)
    left.addEventListener('pointerdown', e => onPointerDown('resize-left', e))
    right.addEventListener('pointerdown', e => onPointerDown('resize-right', e))
    span.addEventListener('pointerdown', e => {
      if ((e.target).classList && (e.target).classList.contains('resize-handle')) return
      onPointerDown('move', e)
    })
    
    // Touch support (for compatibility with older mobile browsers)
    left.addEventListener('touchstart', e => onPointerDown('resize-left', e), { passive: false })
    right.addEventListener('touchstart', e => onPointerDown('resize-right', e), { passive: false })
    span.addEventListener('touchstart', e => {
      if ((e.target).classList && (e.target).classList.contains('resize-handle')) return
      onPointerDown('move', e)
    }, { passive: false })
    overlay.appendChild(span)
  }
}