// SPDX-License-Identifier: EUPL-1.2

// First-match value helpers for the Core framework — pick the first value from a

// list that passes a simple test, the "fallback chain" pattern (config → env →

// default) reduced to one call.

package core

// Coalesce returns the first non-zero value, or the zero value when every

// argument is zero — the fallback chain (primary, secondary, default) as one

// call. Replaces the hand-rolled firstNonEmpty/firstNonNil helpers scattered

// across consumers.

//

// name := core.Coalesce(req.Name, cfg.Name, "anonymous")

// timeout := core.Coalesce(flag, env, 30)

func Coalesce[T comparable](vals ...T) T {

var zero T

for _, v := range vals {

if v != zero {

return v

}

}

return zero

}

// FirstNonBlank returns the first value whose trimmed form is non-empty — a

// whitespace-only string (" ") counts as blank and falls through — returning

// the ORIGINAL untrimmed value, or "" when every value is blank. The

// whitespace-aware sibling of Coalesce for the "first meaningful string" pattern,

// where a blank field should defer to the next fallback.

//

// title := core.FirstNonBlank(userTitle, cfg.Title, "untitled")

func FirstNonBlank(vals ...string) string {

for _, v := range vals {

// The v != "" fast path skips the Trim call for the common empty arg.

if v != "" && Trim(v) != "" {

return v

}

}

return ""

}

// FirstPositive returns the first value strictly greater than the zero value, or

// the zero value when none is — the numeric fallback chain (a value of 0 means

// "unset, try the next"). For numbers this reads as "first positive"; the

// Ordered constraint also admits strings, where it degenerates to Coalesce.

//

// patchSize := core.FirstPositive(cfg.PatchSize, defaultPatchSize)

// softTokens := core.FirstPositive(override, computed, 256)

func FirstPositive[T Ordered](vals ...T) T {

var zero T

for _, v := range vals {

if v > zero {

return v

}

}

return zero

}