import type { CaseState, Evidence, TimelineRange, Viewport, WidgetRelation } from './types'

export const MIN_BOARD_ZOOM = 0.45
export const MAX_BOARD_ZOOM = 1.5

export function clampBoardZoom(zoom: number) {
  return Math.max(MIN_BOARD_ZOOM, Math.min(MAX_BOARD_ZOOM, zoom))
}

export function zoomFromWheel(currentZoom: number, deltaY: number) {
  return clampBoardZoom(currentZoom - deltaY * 0.0015)
}

export function zoomFromPinch(currentZoom: number, previousDistance: number, nextDistance: number) {
  if (!Number.isFinite(previousDistance) || !Number.isFinite(nextDistance) || previousDistance <= 0 || nextDistance <= 0) return currentZoom
  return clampBoardZoom(currentZoom * nextDistance / previousDistance)
}

export function moveBoardPoint(origin: { x: number; y: number }, screenDelta: { x: number; y: number }, zoom: number) {
  if (!Number.isFinite(zoom) || zoom <= 0) throw new RangeError('Board zoom must be positive')
  return { x: origin.x + screenDelta.x / zoom, y: origin.y + screenDelta.y / zoom }
}

export function nextOpenBoardPosition(
  evidence: Pick<Evidence, 'x' | 'y' | 'width'>[],
  preferred: { x: number; y: number },
  size: { width: number; height?: number },
  bounds = { width: 2400, height: 1500 },
) {
  const height = size.height || 160
  const gap = 28
  const overlaps = (x: number, y: number) => evidence.some(item =>
    x < item.x + item.width + gap && x + size.width + gap > item.x &&
    y < item.y + 160 + gap && y + height + gap > item.y)
  const xStep = size.width + 46
  const yStep = height + 46
  for (let row = 0; row < 7; row += 1) {
    for (const column of [0, 1, -1, 2, -2, 3, -3]) {
      const x = Math.max(80, Math.min(bounds.width - size.width - 80, preferred.x + column * xStep))
      const y = Math.max(100, Math.min(bounds.height - height - 80, preferred.y + row * yStep))
      if (!overlaps(x, y)) return { x, y }
    }
  }
  return { x: Math.max(80, Math.min(bounds.width - size.width - 80, preferred.x)), y: Math.min(bounds.height - height - 80, preferred.y + evidence.length * 24) }
}

export function panViewport(origin: Viewport, screenDelta: { x: number; y: number }): Viewport {
  return { ...origin, x: origin.x + screenDelta.x, y: origin.y + screenDelta.y }
}

export function dateValue(date: string) {
  const parsed = Date.parse(date)
  return Number.isFinite(parsed) ? parsed : 0
}

export function timelineRange(dates: string[], fallbackYear = new Date().getFullYear(), configured?: TimelineRange) {
  if (configured) {
    const start = Date.parse(`${configured.start}T00:00:00.000Z`)
    const end = Date.parse(`${configured.end}T23:59:59.999Z`)
    if (Number.isFinite(start) && Number.isFinite(end) && end > start) {
      return { startYear: Number(configured.start.slice(0, 4)), endYear: Number(configured.end.slice(0, 4)), start, end }
    }
  }
  const years = dates
    .map(date => Number(date.slice(0, 4)))
    .filter(year => Number.isFinite(year) && year >= 1 && year <= 9999)
  let startYear = years.length ? Math.min(...years) : fallbackYear - 2
  let endYear = years.length ? Math.max(...years) : startYear + 4
  if (endYear - startYear < 4) {
    const missing = 4 - (endYear - startYear)
    startYear -= Math.floor(missing / 2)
    endYear += Math.ceil(missing / 2)
  }
  return { startYear, endYear, start: Date.UTC(startYear, 0, 1), end: Date.UTC(endYear, 11, 31) }
}

export function timelinePositionPercent(date: string, range: Pick<ReturnType<typeof timelineRange>, 'start' | 'end'>) {
  if (range.end <= range.start) throw new RangeError('Timeline range must have positive duration')
  return Math.max(0, Math.min(100, ((dateValue(date) - range.start) / (range.end - range.start)) * 100))
}

export function containedIds(state: CaseState, widgetId: string) {
  return state.relations
    .filter(relation => relation.type === 'contains' && relation.fromWidgetId === widgetId)
    .sort((a, b) => (a.sortOrder || 0) - (b.sortOrder || 0))
    .map(relation => relation.toWidgetId)
}

export function folderIsOpen(folder: Evidence) {
  return folder.config?.open === true
}

export function relationPosition(state: CaseState, relation: WidgetRelation) {
  const folder = state.evidence.find(widget => widget.id === relation.fromWidgetId)
  const order = relation.sortOrder || 0
  const configuredX = Number(relation.config?.x)
  const configuredY = Number(relation.config?.y)
  return {
    x: Number.isFinite(configuredX) ? configuredX : (folder?.x || 100) + (folder?.width || 240) + 90 + (order % 3) * 205,
    y: Number.isFinite(configuredY) ? configuredY : (folder?.y || 100) - 30 + Math.floor(order / 3) * 185,
  }
}

export function normalizeCase(state: CaseState): CaseState {
  const relations = Array.isArray(state.relations)
    ? state.relations
    : state.evidence.flatMap(widget => (widget.containedDocumentIds || (widget.sourceDocumentId ? [widget.sourceDocumentId] : [])).map((documentId, index) => ({
      id: `contains:${widget.id}:${documentId}`,
      fromWidgetId: widget.id,
      toWidgetId: documentId,
      type: 'contains',
      sortOrder: index,
    })))
  const normalized = { ...state, relations }
  return {
    ...normalized,
    brief: state.brief || { body: '', concepts: [] },
    documents: state.documents.map(document => ({
      ...document,
      fileType: document.fileType || (document.mimeType?.startsWith('image/') ? 'image' : document.mimeType === 'application/pdf' ? 'pdf' : 'file'),
      metadata: document.metadata || {},
    })),
    evidence: state.evidence.map(widget => ({
      ...widget,
      type: widget.type === 'evidence' ? 'folder' : widget.type,
      config: widget.config || {},
      containedDocumentIds: containedIds(normalized, widget.id),
    })),
  }
}