// Package handler provides HTTP handlers for various endpoints.
package handler

import (
	"fmt"
	"strings"

	"modelRT/common/errcode"
	"modelRT/constants"
	"modelRT/database"
	"modelRT/diagram"
	"modelRT/logger"
	"modelRT/network"
	"modelRT/orm"

	"github.com/gin-gonic/gin"
)

// ComponentAttributeUpdateHandler define circuit diagram component attribute value update process API
func ComponentAttributeUpdateHandler(c *gin.Context) {
	pgClient := database.GetPostgresDBClient()
	var request network.ComponentAttributeUpdateInfo
	if err := c.ShouldBindJSON(&request); err != nil {
		logger.Error(c, "unmarshal request params failed", "error", err)
		renderRespFailure(c, constants.RespCodeInvalidParams, err.Error(), nil)
		return
	}

	updateResults := make(map[string]*errcode.AppError)
	attriModifyConfs := make([]attributeModifyConfig, 0, len(request.AttributeConfigs))
	var attributeComponentTag string
	for index, attribute := range request.AttributeConfigs {
		slices := strings.Split(attribute.AttributeToken, ".")
		if len(slices) < 7 {
			updateResults[attribute.AttributeToken] = errcode.ErrInvalidToken
			continue
		}

		componentTag := slices[4]
		if index == 0 {
			attributeComponentTag = componentTag
		} else if componentTag != attributeComponentTag {
			updateResults[attribute.AttributeToken] = errcode.ErrCrossToken
			continue
		}

		attriModifyConfs = append(attriModifyConfs, attributeModifyConfig{
			attributeToken:      attribute.AttributeToken,
			attributeExtendType: slices[5],
			attributeName:       slices[6],
			attributeOldVal:     attribute.AttributeOldVal,
			attributeNewVal:     attribute.AttributeNewVal,
		})
	}

	// open transaction
	tx := pgClient.WithContext(c).Begin()
	if tx.Error != nil {
		logger.Error(c, "begin postgres transaction failed", "error", tx.Error)
		renderRespFailure(c, constants.RespCodeServerError, "begin postgres transaction failed", nil)
		return
	}

	compInfo, err := database.QueryComponentByCompTag(c, tx, attributeComponentTag)
	if err != nil {
		logger.Error(c, "query component info by component tag failed", "error", err, "tag", attributeComponentTag)

		for _, attribute := range request.AttributeConfigs {
			if _, exists := updateResults[attribute.AttributeToken]; !exists {
				updateResults[attribute.AttributeToken] = errcode.ErrDBQueryFailed.WithCause(err)
			}
		}

		tx.Rollback()

		payload := genUpdateRespPayload(updateResults, request.AttributeConfigs)
		renderRespFailure(c, constants.RespCodeFailed, "query component metadata failed", payload)
		return
	}

	identifiers := make([]orm.ProjectIdentifier, len(attriModifyConfs))
	for i, mod := range attriModifyConfs {
		identifiers[i] = orm.ProjectIdentifier{
			Token:     mod.attributeToken,
			Tag:       compInfo.ModelName,
			GroupName: mod.attributeExtendType,
		}
	}
	tableNameMap, err := database.BatchGetProjectNames(tx, identifiers)
	if err != nil {
		tx.Rollback()

		for _, id := range identifiers {
			if _, exists := updateResults[id.Token]; !exists {
				updateResults[id.Token] = errcode.ErrRetrieveFailed.WithCause(err)
			}
		}

		payload := genUpdateRespPayload(updateResults, request.AttributeConfigs)
		renderRespFailure(c, constants.RespCodeFailed, "batch retrieve table names failed", payload)
		return
	}

	redisUpdateMap := make(map[string][]cacheUpdateItem)
	for _, mod := range attriModifyConfs {
		id := orm.ProjectIdentifier{Tag: compInfo.ModelName, GroupName: mod.attributeExtendType}
		tableName, exists := tableNameMap[id]
		if !exists {
			updateResults[mod.attributeToken] = errcode.ErrFoundTargetFailed
			continue
		}

		result := tx.Table(tableName).
			Where(fmt.Sprintf("%s = ? AND global_uuid = ?", mod.attributeName), mod.attributeOldVal, compInfo.GlobalUUID).
			Updates(map[string]any{mod.attributeName: mod.attributeNewVal})

		if result.Error != nil {
			updateResults[mod.attributeToken] = errcode.ErrDBUpdateFailed
			continue
		}
		if result.RowsAffected == 0 {
			updateResults[mod.attributeToken] = errcode.ErrDBzeroAffectedRows
			continue
		}

		cacheKey := fmt.Sprintf("%s_%s", attributeComponentTag, mod.attributeExtendType)
		redisUpdateMap[cacheKey] = append(redisUpdateMap[cacheKey],
			cacheUpdateItem{
				token:  mod.attributeToken,
				name:   mod.attributeName,
				newVal: mod.attributeNewVal,
			})
	}

	// commit transaction
	if err := tx.Commit().Error; err != nil {
		renderRespFailure(c, constants.RespCodeServerError, "transaction commit failed", nil)
		return
	}

	for key, items := range redisUpdateMap {
		hset := diagram.NewRedisHash(c, key, 5000, false)

		fields := make(map[string]any, len(items))
		for _, item := range items {
			fields[item.name] = item.newVal
		}

		if err := hset.SetRedisHashByMap(fields); err != nil {
			logger.Error(c, "batch sync redis failed", "hash_key", key, "error", err)

			for _, item := range items {
				if _, exists := updateResults[item.token]; exists {
					updateResults[item.token] = errcode.ErrCacheSyncWarn.WithCause(err)
				}
			}
		}
	}

	payload := genUpdateRespPayload(updateResults, request.AttributeConfigs)
	if len(updateResults) > 0 {
		renderRespFailure(c, constants.RespCodeFailed, "process completed with partial failures", payload)
		return
	}
	renderRespSuccess(c, constants.RespCodeSuccess, "process completed successfully", payload)
}

type attributeModifyConfig struct {
	attributeToken      string
	attributeExtendType string
	attributeName       string
	attributeOldVal     string
	attributeNewVal     string
}

type cacheUpdateItem struct {
	token  string
	name   string
	newVal string
}

type attributeUpdateResult struct {
	Token string `json:"token"`
	Code  int    `json:"code"`
	Msg   string `json:"msg"`
}

func genUpdateRespPayload(updateResults map[string]*errcode.AppError, originalRequests []network.ComponentAttributeConfig) map[string]any {
	attributes := make([]attributeUpdateResult, 0, len(originalRequests))

	for _, req := range originalRequests {
		token := req.AttributeToken

		if appErr, exists := updateResults[token]; exists {
			attributes = append(attributes, attributeUpdateResult{
				Token: token,
				Code:  appErr.Code(),
				Msg:   appErr.Msg(),
			})
		} else {
			attributes = append(attributes, attributeUpdateResult{
				Token: token,
				Code:  constants.CodeSuccess,
				Msg:   "token value update success",
			})
		}
	}

	payload := map[string]any{
		"attributes": attributes,
	}

	return payload
}