package contract

import (
	"bytes"
	"encoding/json"
	"time"

	"github.com/google/uuid"
)

type CreateCategoryRequest struct {
	Name            string                 `json:"name" validate:"required,min=1,max=255"`
	Description     *string                `json:"description,omitempty"`
	BusinessType    *string                `json:"business_type,omitempty"`
	OutletID        *uuid.UUID             `json:"outlet_id,omitempty"`
	ParentID        *uuid.UUID             `json:"parent_id,omitempty"`
	Order           *int                   `json:"order,omitempty"`
	OwnerFeePercent *float64               `json:"owner_fee_percent,omitempty"`
	IsTeam          *bool                  `json:"is_team,omitempty"`
	Metadata        map[string]interface{} `json:"metadata,omitempty"`
}

type UpdateCategoryRequest struct {
	Name            *string                `json:"name,omitempty" validate:"omitempty,min=1,max=255"`
	Description     *string                `json:"description,omitempty"`
	BusinessType    *string                `json:"business_type,omitempty"`
	OutletID        *uuid.UUID             `json:"outlet_id,omitempty"`
	ParentID        *uuid.UUID             `json:"parent_id,omitempty"`
	Order           *int                   `json:"order,omitempty"`
	OwnerFeePercent *float64               `json:"owner_fee_percent,omitempty"`
	IsTeam          *bool                  `json:"is_team,omitempty"`
	Metadata        map[string]interface{} `json:"metadata,omitempty"`

	// Set when the field is sent as null (or "" for parent_id), which asks for the
	// value to be removed. A field that is left out stays unchanged.
	ClearParentID        bool `json:"-"`
	ClearOwnerFeePercent bool `json:"-"`
}

// UnmarshalJSON tells an explicit null apart from a field that was left out, so a
// category can be detached from its parent and an owner fee override can be removed.
func (r *UpdateCategoryRequest) UnmarshalJSON(data []byte) error {
	var raw map[string]json.RawMessage
	if err := json.Unmarshal(data, &raw); err != nil {
		return err
	}

	isEmpty := func(key string, allowEmptyString bool) bool {
		value, ok := raw[key]
		if !ok {
			return false
		}
		value = bytes.TrimSpace(value)
		return bytes.Equal(value, []byte("null")) || (allowEmptyString && bytes.Equal(value, []byte(`""`)))
	}

	clearParentID := isEmpty("parent_id", true)
	clearOwnerFeePercent := isEmpty("owner_fee_percent", false)
	if clearParentID {
		// An empty string is not a valid UUID, so keep it away from the decoder
		delete(raw, "parent_id")
		cleaned, err := json.Marshal(raw)
		if err != nil {
			return err
		}
		data = cleaned
	}

	type plain UpdateCategoryRequest
	var decoded plain
	if err := json.Unmarshal(data, &decoded); err != nil {
		return err
	}

	*r = UpdateCategoryRequest(decoded)
	r.ClearParentID = clearParentID
	r.ClearOwnerFeePercent = clearOwnerFeePercent
	return nil
}

type ListCategoriesRequest struct {
	OrganizationID *uuid.UUID `json:"organization_id,omitempty"`
	OutletID       *uuid.UUID `json:"outlet_id,omitempty"`
	ParentID       *uuid.UUID `json:"parent_id,omitempty"`
	Type           string     `json:"type,omitempty" validate:"omitempty,oneof=parent child"`
	BusinessType   string     `json:"business_type,omitempty"`
	Search         string     `json:"search,omitempty"`
	Page           int        `json:"page" validate:"required,min=1"`
	Limit          int        `json:"limit" validate:"required,min=1,max=100"`
}

// Category Response DTOs
type CategoryResponse struct {
	ID              uuid.UUID              `json:"id"`
	OrganizationID  uuid.UUID              `json:"organization_id"`
	OutletID        *uuid.UUID             `json:"outlet_id"`
	ParentID        *uuid.UUID             `json:"parent_id,omitempty"`
	ParentName      *string                `json:"parent_name,omitempty"`
	Name            string                 `json:"name"`
	Description     *string                `json:"description"`
	BusinessType    string                 `json:"business_type"`
	Order           int                    `json:"order"`
	OwnerFeePercent *float64               `json:"owner_fee_percent"`
	IsTeam          bool                   `json:"is_team"`
	Metadata        map[string]interface{} `json:"metadata"`
	CreatedAt       time.Time              `json:"created_at"`
	UpdatedAt       time.Time              `json:"updated_at"`
}

type ListCategoriesResponse struct {
	Categories []CategoryResponse `json:"categories"`
	TotalCount int                `json:"total_count"`
	Page       int                `json:"page"`
	Limit      int                `json:"limit"`
	TotalPages int                `json:"total_pages"`
}