gno.land/p/nym-vikbez000/nightsky/v1⧉

1package nightsky23import (4	"gno.land/p/nt/avl/v0"5	"gno.land/p/nt/ufmt/v0"6)78// CaptureFeed is a bounded, newest-first collection of CaptureResult values9// backed by an avl.Tree. It is used for both a single telescope's history and10// the network-wide recent feed.11//12// Entries are keyed by a zero-padded, monotonically increasing sequence so the13// tree iterates in insertion order. Newest-first reads use ReverseIterate, and14// trimming removes the lowest key (the oldest entry). This avoids the O(n)15// slice-prepend the previous implementation paid on every insert, and only16// loads the search path on access instead of the whole collection.17type CaptureFeed struct {18	tree *avl.Tree19	seq  int20	max  int21}2223// NewCaptureFeed creates a feed that keeps at most max entries.24func NewCaptureFeed(max int) *CaptureFeed {25	if max <= 0 {26		panic("capture feed size must be positive")27	}28	return &CaptureFeed{29		tree: avl.NewTree(),30		seq:  0,31		max:  max,32	}33}3435// feedKey renders a sequence into a fixed-width key so that string ordering36// matches numeric ordering.37func feedKey(seq int) string {38	return ufmt.Sprintf("%020d", seq)39}4041// Add inserts a capture as the newest entry and trims the oldest if the feed is42// over capacity.43func (f *CaptureFeed) Add(c CaptureResult) {44	f.seq++45	f.tree.Set(feedKey(f.seq), c)4647	for f.tree.Size() > f.max {48		oldest, _ := f.tree.GetByIndex(0)49		f.tree.Remove(oldest)50	}51}5253// Len returns the number of stored captures.54func (f *CaptureFeed) Len() int {55	return f.tree.Size()56}5758// Latest returns the most recent capture, if any.59func (f *CaptureFeed) Latest() (CaptureResult, bool) {60	if f.tree.Size() == 0 {61		return CaptureResult{}, false62	}63	_, value := f.tree.GetByIndex(f.tree.Size() - 1)64	return value.(CaptureResult), true65}6667// RemoveAt removes the index-th newest capture (0 = most recent). It reports68// whether a capture was removed. Used for moderation of individual entries.69func (f *CaptureFeed) RemoveAt(index int) bool {70	size := f.tree.Size()71	if index < 0 || index >= size {72		return false73	}74	// Newest-first index i maps to ascending-key index (size-1-i).75	key, _ := f.tree.GetByIndex(size - 1 - index)76	_, removed := f.tree.Remove(key)77	return removed78}7980// IterateNewest calls cb for each capture from newest to oldest. Return true81// from cb to stop early.82func (f *CaptureFeed) IterateNewest(cb func(c CaptureResult) bool) {83	f.tree.ReverseIterate("", "", func(_ string, value any) bool {84		return cb(value.(CaptureResult))85	})86}87