// Package jevdecide is an HTTP client for the local jev-service typed decide API.
// Product wiring is fail-open: timeouts, auth errors, and circuit opens fall back
// to existing deterministic rules. See .doc/ops/short-term/2026-09-24-jev-product-shadow.md.
package jevdecide

import "strings"

// Mode controls product-side integration.
type Mode string

const (
	ModeOff    Mode = "off"    // zero behavior change (default)
	ModeShadow Mode = "shadow" // rules route; jev recorded for comparison
	ModeAssist Mode = "assist" // jev may augment selected decisions (with rule floor)
)

// Question is one typed decide question (choice / noul / numeric).
type Question struct {
	Type     string   `json:"type"`
	Question string   `json:"question"`
	Options  []string `json:"options,omitempty"`
	Min      *float64 `json:"min,omitempty"`
	Max      *float64 `json:"max,omitempty"`
}

// Answer is one typed decide answer.
type Answer struct {
	Type          string             `json:"type"`
	Choice        string             `json:"choice,omitempty"`
	Confidence    float64            `json:"confidence"`
	Probabilities map[string]float64 `json:"probabilities,omitempty"`
	Yes           bool               `json:"yes,omitempty"`
	Noul          float64            `json:"noul,omitempty"`
	Value         float64            `json:"value,omitempty"`
	Error         string             `json:"error,omitempty"`
}

// Response is the /v1/decide envelope.
type Response struct {
	Model   string            `json:"model"`
	Answers map[string]Answer `json:"answers"`
}

// Margin returns top1−top2 probability gap (0 if fewer than two options).
func (a Answer) Margin() float64 {
	if len(a.Probabilities) < 2 {
		return a.Confidence
	}
	var top1, top2 float64
	for _, p := range a.Probabilities {
		if p >= top1 {
			top2 = top1
			top1 = p
		} else if p > top2 {
			top2 = p
		}
	}
	return top1 - top2
}

// Reliable reports whether the answer is usable for assist routing.
func (a Answer) Reliable(minConf, minMargin float64) bool {
	if a.Error != "" || strings.TrimSpace(a.Choice) == "" {
		return false
	}
	return a.Confidence >= minConf && a.Margin() >= minMargin
}

// ProfileBucket maps a complexity score to a closed enum for jev choice.
func ProfileBucket(score int) string {
	switch {
	case score >= 60:
		return "high"
	case score >= 30:
		return "mid"
	default:
		return "low"
	}
}