package nslogic

import (
	"strconv"

	"gno.land/r/nym-mnsrehearsal001/nsdata/v2"
)

// GENERATED BY tools/gen-reserved.py FROM collections/reserved-labels.json.
// Do not edit by hand: the site reads the same source, and a change made
// in one place only is a label the site offers and the chain refuses.
//
// STRUCTURAL RULES ONLY. The wordlists live off chain, in that JSON,
// because storage is 100 ugnot per byte and a ten-thousand-word
// dictionary is about 57 GNOT paid forever to encode a marketing
// decision that will change. This is the backstop against a bug in the
// issuer, not the place the policy lives.
//
// THE NUMBERS ARE SETTABLE, the shape is not. A minimum length is a
// promotion knob and belongs in the panel — redeploying this realm to
// change a 5 to a 4 costs about 22 GNOT. So the lengths read from the
// vault's globals and fall back to the values generated here; the
// pattern rules are structural facts about what a handle looks like and
// stay in code.

const (
	defaultFreeMinLength = 5
	defaultFreeMaxLength = 63

	keyFreeMin = "freemin"
	keyFreeMax = "freemax"
)

// FreeMinLength is the shortest label the free tier will issue. Settable
// from the panel, because which lengths are worth money is a commercial
// judgement that moves.
func FreeMinLength() int {
	if v := nsdata.GetGlobal(keyFreeMin); v != "" {
		if n, err := strconv.Atoi(v); err == nil && n > 0 && n <= 63 {
			return n
		}
	}
	return defaultFreeMinLength
}

func FreeMaxLength() int {
	if v := nsdata.GetGlobal(keyFreeMax); v != "" {
		if n, err := strconv.Atoi(v); err == nil && n > 0 && n <= 63 {
			return n
		}
	}
	return defaultFreeMaxLength
}

/*
FreeLabelAllowed reports whether a label may be ISSUED on the free tier.

ISSUED, and never renewed. This is called by GrantFreeName and by
nothing else, deliberately: if the minimum length rises from three to
five, somebody who already holds a three-character free name keeps it
and keeps renewing it free. Tightening a rule must not reach backwards
and take away what was already given — that is the single fastest way to
make a giveaway cost more trust than it ever bought.

A name that LAPSES and is registered again is a new issuance, and gets
whatever the rules say that day. That is not retroactive; it is a
different name event.
*/
func FreeLabelAllowed(label string) bool {
	n := len(label)
	if n < FreeMinLength() || n > FreeMaxLength() {
		return false
	}
	// Pure digits: 1337, 420, years. Collectible, and no handle is one.
	digits := true
	for i := 0; i < n; i++ {
		if label[i] < '0' || label[i] > '9' {
			digits = false
			break
		}
	}
	if digits {
		return false
	}
	// aaaa — every character the same.
	same := true
	for i := 1; i < n; i++ {
		if label[i] != label[0] {
			same = false
			break
		}
	}
	if same {
		return false
	}
	// abab — a two-character cycle. Also collectible, also not a handle.
	if n >= 4 {
		cycle := true
		for i := 2; i < n; i++ {
			if label[i] != label[i-2] {
				cycle = false
				break
			}
		}
		if cycle {
			return false
		}
	}
	return true
}