package validator

import (
	"errors"
	"strings"
	"time"

	"apskel-pos-be/internal/constants"
	"apskel-pos-be/internal/contract"
)

type CampaignValidator interface {
	ValidateCreateCampaignRequest(req *contract.CreateCampaignRequest) (error, string)
	ValidateUpdateCampaignRequest(req *contract.UpdateCampaignRequest) (error, string)
	ValidateListCampaignsRequest(req *contract.ListCampaignsRequest) (error, string)
	ValidateGetCampaignRequest(req *contract.GetCampaignRequest) (error, string)
	ValidateDeleteCampaignRequest(req *contract.DeleteCampaignRequest) (error, string)
	ValidateCreateCampaignRuleRequest(req *contract.CreateCampaignRuleRequest) (error, string)
	ValidateUpdateCampaignRuleRequest(req *contract.UpdateCampaignRuleRequest) (error, string)
	ValidateListCampaignRulesRequest(req *contract.ListCampaignRulesRequest) (error, string)
	ValidateGetCampaignRuleRequest(req *contract.GetCampaignRuleRequest) (error, string)
	ValidateDeleteCampaignRuleRequest(req *contract.DeleteCampaignRuleRequest) (error, string)
}

type CampaignValidatorImpl struct{}

func NewCampaignValidator() CampaignValidator {
	return &CampaignValidatorImpl{}
}

func (v *CampaignValidatorImpl) ValidateCreateCampaignRequest(req *contract.CreateCampaignRequest) (error, string) {
	if req == nil {
		return errors.New("request is required"), constants.ValidationErrorCode
	}

	// Validate name
	if strings.TrimSpace(req.Name) == "" {
		return errors.New("campaign name is required"), constants.ValidationErrorCode
	}
	if len(req.Name) > 150 {
		return errors.New("campaign name cannot exceed 150 characters"), constants.ValidationErrorCode
	}

	// Validate campaign type
	if !v.isValidCampaignType(req.Type) {
		return errors.New("invalid campaign type. Valid types are: REWARD, POINTS, TOKENS, MIXED"), constants.ValidationErrorCode
	}

	// Validate date range
	if err := v.validateDateRange(req.StartDate, req.EndDate); err != nil {
		return err, constants.ValidationErrorCode
	}

	// Validate position
	if req.Position < 0 {
		return errors.New("position cannot be negative"), constants.ValidationErrorCode
	}

	// Validate rules
	if len(req.Rules) == 0 {
		return errors.New("at least one rule is required"), constants.ValidationErrorCode
	}

	for i, rule := range req.Rules {
		if err := v.validateCampaignRule(&rule, i+1); err != nil {
			return err, constants.ValidationErrorCode
		}
	}

	return nil, ""
}

func (v *CampaignValidatorImpl) ValidateUpdateCampaignRequest(req *contract.UpdateCampaignRequest) (error, string) {
	if req == nil {
		return errors.New("request is required"), constants.ValidationErrorCode
	}

	// Validate ID
	if req.ID.String() == "" {
		return errors.New("campaign ID is required"), constants.ValidationErrorCode
	}

	// Validate name
	if strings.TrimSpace(req.Name) == "" {
		return errors.New("campaign name is required"), constants.ValidationErrorCode
	}
	if len(req.Name) > 150 {
		return errors.New("campaign name cannot exceed 150 characters"), constants.ValidationErrorCode
	}

	// Validate campaign type
	if !v.isValidCampaignType(req.Type) {
		return errors.New("invalid campaign type. Valid types are: REWARD, POINTS, TOKENS, MIXED"), constants.ValidationErrorCode
	}

	// Validate date range
	if err := v.validateDateRange(req.StartDate, req.EndDate); err != nil {
		return err, constants.ValidationErrorCode
	}

	// Validate position
	if req.Position < 0 {
		return errors.New("position cannot be negative"), constants.ValidationErrorCode
	}

	// Validate rules
	if len(req.Rules) == 0 {
		return errors.New("at least one rule is required"), constants.ValidationErrorCode
	}

	for i, rule := range req.Rules {
		if err := v.validateCampaignRule(&rule, i+1); err != nil {
			return err, constants.ValidationErrorCode
		}
	}

	return nil, ""
}

func (v *CampaignValidatorImpl) ValidateListCampaignsRequest(req *contract.ListCampaignsRequest) (error, string) {
	if req == nil {
		return errors.New("request is required"), constants.ValidationErrorCode
	}

	// Validate pagination
	if req.Page < 1 {
		return errors.New("page must be greater than 0"), constants.ValidationErrorCode
	}
	if req.Limit < 1 {
		return errors.New("limit must be greater than 0"), constants.ValidationErrorCode
	}
	if req.Limit > 100 {
		return errors.New("limit cannot exceed 100"), constants.ValidationErrorCode
	}

	// Validate campaign type filter if provided
	if req.Type != "" && !v.isValidCampaignType(req.Type) {
		return errors.New("invalid campaign type filter. Valid types are: REWARD, POINTS, TOKENS, MIXED"), constants.ValidationErrorCode
	}

	return nil, ""
}

func (v *CampaignValidatorImpl) ValidateGetCampaignRequest(req *contract.GetCampaignRequest) (error, string) {
	if req == nil {
		return errors.New("request is required"), constants.ValidationErrorCode
	}

	if req.ID.String() == "" {
		return errors.New("campaign ID is required"), constants.ValidationErrorCode
	}

	return nil, ""
}

func (v *CampaignValidatorImpl) ValidateDeleteCampaignRequest(req *contract.DeleteCampaignRequest) (error, string) {
	if req == nil {
		return errors.New("request is required"), constants.ValidationErrorCode
	}

	if req.ID.String() == "" {
		return errors.New("campaign ID is required"), constants.ValidationErrorCode
	}

	return nil, ""
}

func (v *CampaignValidatorImpl) ValidateCreateCampaignRuleRequest(req *contract.CreateCampaignRuleRequest) (error, string) {
	if req == nil {
		return errors.New("request is required"), constants.ValidationErrorCode
	}

	// Validate campaign ID
	if req.CampaignID.String() == "" {
		return errors.New("campaign ID is required"), constants.ValidationErrorCode
	}

	// Validate rule
	if err := v.validateCampaignRule(&contract.CampaignRuleStruct{
		RuleType:       req.RuleType,
		ConditionValue: req.ConditionValue,
		RewardType:     req.RewardType,
		RewardValue:    req.RewardValue,
		RewardSubtype:  req.RewardSubtype,
		RewardRefID:    req.RewardRefID,
		Metadata:       req.Metadata,
	}, 1); err != nil {
		return err, constants.ValidationErrorCode
	}

	return nil, ""
}

func (v *CampaignValidatorImpl) ValidateUpdateCampaignRuleRequest(req *contract.UpdateCampaignRuleRequest) (error, string) {
	if req == nil {
		return errors.New("request is required"), constants.ValidationErrorCode
	}

	// Validate ID
	if req.ID.String() == "" {
		return errors.New("campaign rule ID is required"), constants.ValidationErrorCode
	}

	// Validate campaign ID
	if req.CampaignID.String() == "" {
		return errors.New("campaign ID is required"), constants.ValidationErrorCode
	}

	// Validate rule
	if err := v.validateCampaignRule(&contract.CampaignRuleStruct{
		RuleType:       req.RuleType,
		ConditionValue: req.ConditionValue,
		RewardType:     req.RewardType,
		RewardValue:    req.RewardValue,
		RewardSubtype:  req.RewardSubtype,
		RewardRefID:    req.RewardRefID,
		Metadata:       req.Metadata,
	}, 1); err != nil {
		return err, constants.ValidationErrorCode
	}

	return nil, ""
}

func (v *CampaignValidatorImpl) ValidateListCampaignRulesRequest(req *contract.ListCampaignRulesRequest) (error, string) {
	if req == nil {
		return errors.New("request is required"), constants.ValidationErrorCode
	}

	// Validate pagination
	if req.Page < 1 {
		return errors.New("page must be greater than 0"), constants.ValidationErrorCode
	}
	if req.Limit < 1 {
		return errors.New("limit must be greater than 0"), constants.ValidationErrorCode
	}
	if req.Limit > 100 {
		return errors.New("limit cannot exceed 100"), constants.ValidationErrorCode
	}

	// Validate rule type filter if provided
	if req.RuleType != "" && !v.isValidRuleType(req.RuleType) {
		return errors.New("invalid rule type filter. Valid types are: TIER, SPEND, PRODUCT, CATEGORY, DAY, LOCATION"), constants.ValidationErrorCode
	}

	// Validate reward type filter if provided
	if req.RewardType != "" && !v.isValidRewardType(req.RewardType) {
		return errors.New("invalid reward type filter. Valid types are: POINTS, TOKENS, REWARD"), constants.ValidationErrorCode
	}

	return nil, ""
}

func (v *CampaignValidatorImpl) ValidateGetCampaignRuleRequest(req *contract.GetCampaignRuleRequest) (error, string) {
	if req == nil {
		return errors.New("request is required"), constants.ValidationErrorCode
	}

	if req.ID.String() == "" {
		return errors.New("campaign rule ID is required"), constants.ValidationErrorCode
	}

	return nil, ""
}

func (v *CampaignValidatorImpl) ValidateDeleteCampaignRuleRequest(req *contract.DeleteCampaignRuleRequest) (error, string) {
	if req == nil {
		return errors.New("request is required"), constants.ValidationErrorCode
	}

	if req.ID.String() == "" {
		return errors.New("campaign rule ID is required"), constants.ValidationErrorCode
	}

	return nil, ""
}

func (v *CampaignValidatorImpl) isValidCampaignType(campaignType string) bool {
	validTypes := []string{"REWARD", "POINTS", "TOKENS", "MIXED"}
	return contains(validTypes, campaignType)
}

func (v *CampaignValidatorImpl) isValidRuleType(ruleType string) bool {
	validTypes := []string{"TIER", "SPEND", "PRODUCT", "CATEGORY", "DAY", "LOCATION"}
	return contains(validTypes, ruleType)
}

func (v *CampaignValidatorImpl) isValidRewardType(rewardType string) bool {
	validTypes := []string{"POINTS", "TOKENS", "REWARD"}
	return contains(validTypes, rewardType)
}

func (v *CampaignValidatorImpl) validateDateRange(startDate, endDate time.Time) error {
	if startDate.IsZero() {
		return errors.New("start date is required")
	}
	if endDate.IsZero() {
		return errors.New("end date is required")
	}
	if startDate.After(endDate) {
		return errors.New("start date cannot be after end date")
	}
	return nil
}

func (v *CampaignValidatorImpl) validateCampaignRule(rule *contract.CampaignRuleStruct, ruleNumber int) error {
	if rule == nil {
		return errors.New("rule is required")
	}

	// Validate rule type
	if !v.isValidRuleType(rule.RuleType) {
		return errors.New("invalid rule type in rule " + string(rune(ruleNumber)) + ". Valid types are: TIER, SPEND, PRODUCT, CATEGORY, DAY, LOCATION")
	}

	// Validate reward type
	if !v.isValidRewardType(rule.RewardType) {
		return errors.New("invalid reward type in rule " + string(rune(ruleNumber)) + ". Valid types are: POINTS, TOKENS, REWARD")
	}

	// Validate reward value based on reward type
	if rule.RewardType == "POINTS" || rule.RewardType == "TOKENS" {
		if rule.RewardValue == nil || *rule.RewardValue <= 0 {
			return errors.New("reward value must be positive for " + rule.RewardType + " type in rule " + string(rune(ruleNumber)))
		}
	}

	// Validate reward reference ID for REWARD type
	if rule.RewardType == "REWARD" {
		if rule.RewardRefID == nil {
			return errors.New("reward reference ID is required for REWARD type in rule " + string(rune(ruleNumber)))
		}
	}

	return nil
}