package processing

import (
	"bytes"
	"encoding/json"
)

// v1ProcessItemKeyOrder is the human-readable ProcessItem property order.
// Important catalog fields first; internal ids / SEO last.
var v1ProcessItemKeyOrder = []string{
	"ean",
	"title",
	"name",
	"category",
	"category_id",
	"category_name",
	"description",
	"attributes",
	"main_image",
	"more_images",
	"eprel",
	"status",
	"error",
	"meta_title",
	"meta_description",
}

// v1ProcessItemInternalKeys must never appear on public ProcessItem JSON.
var v1ProcessItemInternalKeys = map[string]struct{}{
	"id":                   {},
	"processed_product_id": {},
	"raw_product_id":       {},
	"field_sources":        {},
	"enhance_input_hash":   {},
	"ai_enhance":           {},
	"finish_reason":        {},
	"gpt_response":         {},
	"total_tokens":         {},
	"prompt_tokens":        {},
	"completion_tokens":    {},
	"ai_provider_mode":     {},
	"notes":                {},
	"worker":               {},
	"model":                {},
	"provider":             {},
}

func stripV1ProcessItemInternalKeys(item V1ProcessJobItem) {
	if item == nil {
		return
	}
	for k := range v1ProcessItemInternalKeys {
		delete(item, k)
	}
}

// MarshalJSON emits only the public ProcessItem allowlist in a stable order.
// Unexpected keys (including pipeline internals) cannot ship.
func (item V1ProcessJobItem) MarshalJSON() ([]byte, error) {
	if item == nil {
		return []byte("null"), nil
	}
	var buf bytes.Buffer
	buf.WriteByte('{')
	first := true
	writePair := func(k string, v any) error {
		if !first {
			buf.WriteByte(',')
		}
		first = false
		kb, err := json.Marshal(k)
		if err != nil {
			return err
		}
		vb, err := json.Marshal(v)
		if err != nil {
			return err
		}
		buf.Write(kb)
		buf.WriteByte(':')
		buf.Write(vb)
		return nil
	}
	for _, k := range v1ProcessItemKeyOrder {
		v, ok := item[k]
		if !ok {
			continue
		}
		if err := writePair(k, v); err != nil {
			return nil, err
		}
	}
	buf.WriteByte('}')
	return buf.Bytes(), nil
}