package pipeline

import (
	"strconv"
	"strings"
	"time"
)

const (
	// RevisionRetentionKey is the global_settings KV for revision TTL (minutes).
	RevisionRetentionKey = "revision_retention_minutes"
	RevisionMinTTLMin    = 15
	RevisionMaxTTLMin    = 30 * 24 * 60
	RevisionDefaultTTL   = 30 * 24 * time.Hour
)

// RevisionCutoffFromMinutes returns created_at cutoff for revision prune (UTC now minus clamped TTL).
func RevisionCutoffFromMinutes(minutes int) time.Time {
	ttl := RevisionDefaultTTL
	if minutes > 0 {
		m := minutes
		if m < RevisionMinTTLMin {
			m = RevisionMinTTLMin
		}
		if m > RevisionMaxTTLMin {
			m = RevisionMaxTTLMin
		}
		ttl = time.Duration(m) * time.Minute
	}
	return time.Now().UTC().Add(-ttl)
}

// RevisionRetentionMinutesFromSettings reads revision_retention_minutes from tenant KV (0 if unset).
func RevisionRetentionMinutesFromSettings(settings map[string]any) int {
	if settings == nil {
		return 0
	}
	v, ok := settings[RevisionRetentionKey]
	if !ok || v == nil {
		return 0
	}
	switch x := v.(type) {
	case float64:
		return int(x)
	case int:
		return x
	case int64:
		return int(x)
	case string:
		n, err := strconv.Atoi(strings.TrimSpace(x))
		if err == nil {
			return n
		}
	}
	return 0
}

// RevisionRetentionCutoff resolves tenant revision_retention_minutes from settings (default 30d).
func RevisionRetentionCutoff(settings map[string]any) time.Time {
	return RevisionCutoffFromMinutes(RevisionRetentionMinutesFromSettings(settings))
}

// ClampRevisionRetentionMinutes normalizes user input to the allowed range.
func ClampRevisionRetentionMinutes(minutes int) int {
	if minutes <= 0 {
		return int(RevisionDefaultTTL / time.Minute)
	}
	if minutes < RevisionMinTTLMin {
		return RevisionMinTTLMin
	}
	if minutes > RevisionMaxTTLMin {
		return RevisionMaxTTLMin
	}
	return minutes
}