package httpapi

import (
	"encoding/json"
	"errors"
	"log/slog"
	"net/http"
	"strings"

	"data-terminal-cloud/internal/memorytool"
)

func MemoryToolSearchHandler(service *memorytool.Service, signer *memorytool.TokenSigner, limiter RateLimiter, logger *slog.Logger) http.Handler {
	if logger == nil {
		logger = slog.Default()
	}
	return http.HandlerFunc(func(writer http.ResponseWriter, request *http.Request) {
		authorization := strings.TrimSpace(request.Header.Get("Authorization"))
		if !strings.HasPrefix(authorization, "Bearer ") {
			WriteError(writer, request, http.StatusUnauthorized, "MEMORY_TOOL_AUTHENTICATION_FAILED", "记忆工具身份验证失败")
			return
		}
		claims, err := signer.Verify(strings.TrimSpace(strings.TrimPrefix(authorization, "Bearer ")))
		if err != nil {
			WriteError(writer, request, http.StatusUnauthorized, "MEMORY_TOOL_AUTHENTICATION_FAILED", "记忆工具身份验证失败")
			return
		}
		if limiter != nil && !allowScopes(writer, request, logger, limiter, [][2]string{{"memory_tool", claims.ConversationID}}) {
			return
		}
		decoder := json.NewDecoder(request.Body)
		decoder.DisallowUnknownFields()
		var input struct {
			Query string `json:"query"`
			Limit int    `json:"limit"`
		}
		if err := decoder.Decode(&input); err != nil || ensureJSONEOF(decoder) != nil {
			WriteError(writer, request, http.StatusBadRequest, "MEMORY_TOOL_INVALID_REQUEST", "记忆检索参数不正确")
			return
		}
		input.Query = strings.TrimSpace(input.Query)
		if input.Limit == 0 {
			input.Limit = 3
		}
		if input.Query == "" || len([]rune(input.Query)) > 500 || input.Limit < 1 || input.Limit > 5 {
			WriteError(writer, request, http.StatusBadRequest, "MEMORY_TOOL_INVALID_REQUEST", "记忆检索参数不正确")
			return
		}
		result, err := service.Search(request.Context(), claims, input.Query, input.Limit, RequestID(request.Context()))
		if err != nil {
			switch {
			case errors.Is(err, memorytool.ErrConversationUnavailable):
				WriteError(writer, request, http.StatusConflict, "MEMORY_TOOL_CONVERSATION_UNAVAILABLE", "本次通话当前不能使用记忆检索")
			case errors.Is(err, memorytool.ErrEngineModeUnsupported):
				WriteError(writer, request, http.StatusConflict, "MEMORY_TOOL_ENGINE_MODE_UNSUPPORTED", "本次语音处理方式未启用通话内记忆工具")
			default:
				slog.ErrorContext(request.Context(), "memory tool search failed", "conversation_id", claims.ConversationID, "error", err)
				WriteAPIError(writer, request, http.StatusServiceUnavailable, Error{Code: "MEMORY_TOOL_UNAVAILABLE", Message: "记忆检索暂时不可用，请继续普通交流", Retryable: true})
			}
			return
		}
		WriteJSON(writer, request, http.StatusOK, result)
	})
}