package eform

import "time"

// =====================================================
// MODIFICATION STRUCTURE
// =====================================================

// Modification represents changes to existing contracts
type Modification struct {
	ID                      string             `json:"id" xml:"id" validate:"required,modIDFormat"`
	OriginalContractID      string             `json:"original_contract_id" xml:"original_contract_id" validate:"required,conIDFormat"`
	Reason                  ModificationReason `json:"reason" xml:"reason" validate:"required"`
	ReasonDescription       string             `json:"reason_description" xml:"reason_description" validate:"required,max=10000"`
	ValueBefore             Money              `json:"value_before" xml:"value_before" validate:"required"`
	ValueAfter              Money              `json:"value_after" xml:"value_after" validate:"required"`
	ValueChange             Money              `json:"value_change" xml:"value_change"`
	PercentageChange        float64            `json:"percentage_change" xml:"percentage_change"`
	DurationBefore          *Duration          `json:"duration_before,omitempty" xml:"duration_before,omitempty"`
	DurationAfter           *Duration          `json:"duration_after,omitempty" xml:"duration_after,omitempty"`
	ModificationDescription string             `json:"modification_description" xml:"modification_description" validate:"required,max=10000"`
	ModificationDate        time.Time          `json:"modification_date" xml:"modification_date" validate:"required"`
	ContractorChange        bool               `json:"contractor_change" xml:"contractor_change"`
	NewContractorIDs        []string           `json:"new_contractor_ids,omitempty" xml:"new_contractor_ids,omitempty"`
}

// ModificationReason represents the reason for contract modification
type ModificationReason string

const (
	ModReasonAdditionalWorks ModificationReason = "add-wks"
	ModReasonUnforeseen      ModificationReason = "unforeseen"
	ModReasonDesignDefect    ModificationReason = "design-defect"
	ModReasonAdditionalNeed  ModificationReason = "additional-need"
	ModReasonRepeatSimilar   ModificationReason = "repeat-similar"
	ModReasonRatePriceUpdate ModificationReason = "rate-price-update"
	ModReasonSuspendCall     ModificationReason = "suspend-call"
	ModReasonOther           ModificationReason = "other"
)

// CalculateModificationChange calculates value change for modifications
func (m *Modification) CalculateModificationChange() {
	if m.ValueBefore.Currency == m.ValueAfter.Currency {
		change := m.ValueAfter.Amount - m.ValueBefore.Amount
		m.ValueChange = Money{
			Amount:   change,
			Currency: m.ValueBefore.Currency,
		}
		if m.ValueBefore.Amount != 0 {
			m.PercentageChange = (change / m.ValueBefore.Amount) * 100
		}
	}
}