package runtime

import (
	"encoding/json"
	"fmt"
	"strings"
	"unicode/utf8"

	core "agent-system-core"
)

const MaterialChoiceOptionsPrefix = "[material-choice-options-v1]:"
const MaterialChoiceReadyMarker = "[material-choice-ready]"

type materialChoiceData struct {
	Label string `json:"label"`
	Basis string `json:"basis"`
}

// The host appends this bounded data line immediately before its ready marker.
// Model prose elsewhere in the notice cannot authorize or replace the choices.
func materialOptionsFromNotice(text string) []core.HITLChoice {
	if !strings.HasSuffix(strings.TrimSpace(text), MaterialChoiceReadyMarker+"\n</system-reminder>") {
		return nil
	}
	idx := strings.LastIndex(text, "\n"+MaterialChoiceOptionsPrefix)
	if idx < 0 {
		return nil
	}
	line := strings.TrimPrefix(text[idx+1:], MaterialChoiceOptionsPrefix)
	if end := strings.IndexByte(line, '\n'); end >= 0 {
		line = line[:end]
	}
	// Four valid UTF-8 labels (80 runes) and bases (240 runes) can exceed
	// 2 KiB even though every item is individually within its limit.
	if len(line) > 8192 {
		return nil
	}
	var data []materialChoiceData
	if err := json.Unmarshal([]byte(line), &data); err != nil || len(data) < 3 || len(data) > 4 {
		return nil
	}
	choices := make([]core.HITLChoice, 0, len(data))
	for i, item := range data {
		label, basis := strings.TrimSpace(item.Label), strings.TrimSpace(item.Basis)
		if label == "" || basis == "" || utf8.RuneCountInString(label) > 80 ||
			utf8.RuneCountInString(basis) > 240 || strings.ContainsAny(label+basis, "<>\r\n") ||
			strings.Contains(label+basis, "sourceId=") {
			return nil
		}
		choices = append(choices, core.HITLChoice{ID: fmt.Sprintf("material-%d", i+1), Label: label,
			Description: basis, Impact: "根据已整理材料生成" + label, Recommended: i == 0})
	}
	return choices
}