package httpapi

import (
	"context"
	"encoding/json"
	"errors"
	"io"
	"knowledge-governance/internal/qaopsmirror"
	"net/http"
	"strings"
)

type qaMirrorSyncStore interface {
	GetSyncStatus(context.Context) (qaopsmirror.Status, error)
	EnqueueSync(context.Context, string, string) (qaopsmirror.SyncReceipt, bool, error)
}

func qaRecordsSync(w http.ResponseWriter, r *http.Request, c Config) {
	if !authorizeQAOps(w, r) {
		return
	}
	if r.URL.RawQuery != "" {
		writeJSON(w, 400, map[string]string{"error": "同步入口不接受查询参数"})
		return
	}
	store, ok := c.QAOps.(qaMirrorSyncStore)
	if !ok || !c.QAOpsEnabled {
		writeJSON(w, 503, map[string]string{"error": "本地问答同步未接线，未创建任务"})
		return
	}
	if r.Method == http.MethodGet {
		state, e := store.GetSyncStatus(r.Context())
		if e != nil {
			qaOpsError(w, e)
			return
		}
		writeJSON(w, 200, map[string]any{"data": state})
		return
	}
	if !authorizeQAIntent(w, r, "qa-records-sync") {
		return
	}
	key := r.Header.Get("Idempotency-Key")
	if key == "" || len(key) > 128 || strings.TrimSpace(key) != key {
		writeJSON(w, 400, map[string]string{"error": "同步请求需要有效 Idempotency-Key，重试须复用原标识"})
		return
	}
	var body *struct{}
	d := json.NewDecoder(http.MaxBytesReader(w, r.Body, 1024))
	d.DisallowUnknownFields()
	if d.Decode(&body) != nil || body == nil || d.Decode(&struct{}{}) != io.EOF {
		writeJSON(w, 400, map[string]string{"error": "同步请求体必须是空对象"})
		return
	}
	identity, _ := sessionFrom(r.Context())
	receipt, replayed, e := store.EnqueueSync(r.Context(), key, identity.Username)
	if e != nil {
		status := 503
		message := "同步未成功入队，已有本地数据保持不变"
		if errors.Is(e, qaopsmirror.ErrInvalid) {
			status = 400
			message = "同步请求标识无效"
		}
		if errors.Is(e, qaopsmirror.ErrConflict) {
			status = 409
			message = "同步标识已用于另一操作，请重新发起"
		}
		if errors.Is(e, qaopsmirror.ErrWorkerUnavailable) {
			message = "问答同步执行器未在线，未创建任务"
		}
		writeJSON(w, status, map[string]string{"error": message})
		return
	}
	operation := "created"
	if replayed {
		operation = "replayed"
	}
	writeJSON(w, 202, map[string]any{"data": receipt, "operation": operation})
}