// Package evidence is the activity port: a dumb active-window sensor behind a
// Source interface, plus the value types it emits. It makes no judgment about
// whether a window is on-task — that is the advisor's job in a later milestone.
package evidence

import (
	"context"
	"regexp"
)

// EvidenceHealth records whether the sensor could observe the active window.
type EvidenceHealth struct {
	Available bool   // true when a window was observed
	Reason    string // empty when Available; populated when not
}

// WindowSnapshot is one observation of the active window.
type WindowSnapshot struct {
	Title  string // full _NET_WM_NAME (raw; used in live view + raw log)
	Class  string // WM_CLASS
	Health EvidenceHealth
}

// Source is the activity port. Watch runs until ctx is cancelled, invoking
// onChange on every active-window change, and once immediately with the
// current window.
type Source interface {
	Watch(ctx context.Context, onChange func(WindowSnapshot))
}

// titleNoise matches the legacy clock/ratio/percent runs that pollute bucket
// keys (e.g. "1:23", "50.5%", "-3.0"). Ported verbatim from the Rust impl.
var titleNoise = regexp.MustCompile(`-?\d+([:.]\d+)+%?`)

// ScrubTitle removes volatile numeric runs so window titles bucket stably.
// The raw event log keeps the unscrubbed title; only bucket keys are scrubbed.
func ScrubTitle(title string) string {
	return titleNoise.ReplaceAllString(title, "")
}