package httpapi

import (
	"bytes"
	"context"
	"encoding/json"
	"errors"
	"io"
	"net/http"
	"strings"

	"data-terminal-cloud/internal/deviceauth"
	"data-terminal-cloud/internal/devicebinding"
	"data-terminal-cloud/internal/devicereset"
	"data-terminal-cloud/internal/idempotency"
)

type DeviceFactoryResetService interface {
	Reset(context.Context, deviceauth.Identity, string, string, []byte, devicereset.Input) (devicereset.Response, bool, error)
}

func DeviceFactoryResetHandler(service DeviceFactoryResetService) http.Handler {
	return http.HandlerFunc(func(writer http.ResponseWriter, request *http.Request) {
		writer.Header().Set("Cache-Control", "no-store")
		writer.Header().Set("Pragma", "no-cache")
		identity, ok := deviceauth.FromContext(request.Context())
		if !ok {
			WriteError(writer, request, http.StatusUnauthorized, "DEVICE_AUTHENTICATION_FAILED", "设备身份验证失败")
			return
		}
		key := strings.TrimSpace(request.Header.Get("Idempotency-Key"))
		if len(key) < 16 || len(key) > 128 {
			WriteError(writer, request, http.StatusBadRequest, "VALIDATION_FAILED", "缺少有效的重复请求识别码")
			return
		}
		rawBody, err := io.ReadAll(request.Body)
		if err != nil {
			WriteError(writer, request, http.StatusBadRequest, "INVALID_REQUEST_BODY", "请求正文无法读取")
			return
		}
		decoder := json.NewDecoder(bytes.NewReader(rawBody))
		decoder.DisallowUnknownFields()
		var input devicereset.Input
		if err := decoder.Decode(&input); err != nil || ensureJSONEOF(decoder) != nil || devicereset.Validate(input) != nil {
			WriteError(writer, request, http.StatusBadRequest, "VALIDATION_FAILED", "设备恢复出厂参数不正确")
			return
		}
		response, replayed, err := service.Reset(request.Context(), identity, key, RequestID(request.Context()), rawBody, input)
		if replayed {
			writer.Header().Set("Idempotency-Replayed", "true")
		}
		if err != nil {
			switch {
			case errors.Is(err, devicebinding.ErrConfirmationRequired):
				WriteError(writer, request, http.StatusConflict, "DEVICE_RESET_AUTHORIZATION_REQUIRED", "请先由当前家庭授权解绑，随后再执行设备重置")
			case errors.Is(err, devicereset.ErrPendingTranscripts):
				WriteError(writer, request, http.StatusConflict, "DEVICE_RESET_PENDING_TRANSCRIPTS", "设备仍有未上传的聊天记录")
			case errors.Is(err, devicereset.ErrCallInProgress):
				WriteError(writer, request, http.StatusConflict, "DEVICE_RESET_CALL_IN_PROGRESS", "设备正在通话，请结束后再恢复出厂")
			case errors.Is(err, devicereset.ErrFirmwareInProgress):
				WriteError(writer, request, http.StatusConflict, "DEVICE_RESET_FIRMWARE_IN_PROGRESS", "设备正在升级固件，暂时不能恢复出厂")
			case errors.Is(err, devicereset.ErrResetCounterConflict):
				WriteError(writer, request, http.StatusConflict, "DEVICE_RESET_COUNTER_CONFLICT", "设备重置计数器不是递增值")
			case errors.Is(err, devicereset.ErrStateConflict):
				WriteError(writer, request, http.StatusConflict, "DEVICE_RESET_STATE_CONFLICT", "当前设备状态不允许恢复出厂")
			case errors.Is(err, idempotency.ErrKeyConflict):
				WriteError(writer, request, http.StatusConflict, "IDEMPOTENCY_KEY_CONFLICT", "重复请求识别码已用于不同的请求")
			case errors.Is(err, idempotency.ErrInProgress):
				WriteAPIError(writer, request, http.StatusConflict, Error{Code: "IDEMPOTENCY_IN_PROGRESS", Message: "相同恢复出厂请求仍在处理中", Retryable: true})
			case errors.Is(err, devicereset.ErrInvalid):
				WriteError(writer, request, http.StatusBadRequest, "VALIDATION_FAILED", "设备恢复出厂参数不正确")
			default:
				WriteAPIError(writer, request, http.StatusServiceUnavailable, Error{Code: "DEVICE_RESET_FAILED", Message: "设备恢复出厂暂时失败", Retryable: true})
			}
			return
		}
		WriteJSON(writer, request, http.StatusOK, response)
	})
}