package webutility

  import (
  	"database/sql"
  	"fmt"
  )

  
  type ListOptions struct {
  	GlobalFilter  bool   `json:"globalFilter"`
  	LocalFilters  bool   `json:"localFilters"`
  	RemoteFilters bool   `json:"remoteFilters"`
  	Pagination    bool   `json:"pagination"`

  	PageSize      uint32 `json:"pageSize"`

  	Pivot         bool   `json:"pivot"`
  	Detail        bool   `json:"detail"`
  	Total         bool   `json:"total"`
  }
  
  type ListFilter struct {
  	Position       uint32   `json:"-"`
  	ObjectType     string   `json:"-"`
  	FiltersField   string   `json:"filtersField"`
  	DefaultValues  string   `json:"defaultValues"`
  	FiltersType    string   `json:"filtersType"`
  	FiltersLabel   string   `json:"filtersLabel"`
  	DropdownConfig Dropdown `json:"dropdownConfig"`
  }
  
  type Dropdown struct {
  	ObjectType   string `json:"objectType"`
  	FiltersField string `json:"filtersField"`
  	IDField      string `json:"idField"`
  	LabelField   string `json:"labelField"`
  }
  
  type ListGraph struct {
  	ObjectType string `json:"objectType"`
  	X          string `json:"xField"`
  	Y          string `json:"yField"`
  	GroupField string `json:"groupField"`
  	Label      string `json:"label"`
  }
  
  type ListActions struct {
  	Create bool `json:"create"`
  	Update bool `json:"update"`
  	Delete bool `json:"delete"`
  	Export bool `json:"export"`
  	Print  bool `json:"print"`
  	Graph  bool `json:"graph"`
  }
  
  type ListNavNode struct {
  	ObjectType        string `json:"objectType"`
  	LabelField        string `json:"label"`
  	Icon              string `json:"icon"`
  	ParentObjectType  string `json:"parentObjectType"`
  	ParentIDField     string `json:"parentIdField"`
  	ParentFilterField string `json:"parentFilterField"`
  }
  
  type ListParentNode struct {
  	ObjectType  string `json:"objectType"`
  	LabelField  string `json:"labelField"`
  	FilterField string `json:"filterField"`
  }
  
  type ListPivot struct {
  	ObjectType    string `json:"objectType"`
  	GroupField    string `json:"groupField"`
  	DistinctField string `json:"distinctField"`
  	Value         string `json:"valueField"`
  }
  
  type ListDetails struct {
  	ObjectType        string `json:"objectType"`
  	ParentObjectType  string `json:"parentObjectType"`
  	ParentFilterField string `json:"parentFilterField"`
  	SingleDetail      bool   `json:"singleDetail"`
  }
  
  type ListConfig struct {
  	ObjectType string           `json:"objectType"`
  	Title      string           `json:"title"`
  	LazyLoad   bool             `json:"lazyLoad"`
  	InlineEdit bool             `json:"inlineEdit"`
  	Options    ListOptions      `json:"options"`
  	Filters    []ListFilter     `json:"defaultFilters"`
  	Graphs     []ListGraph      `json:"graphs"`
  	Actions    ListActions      `json:"actions"`
  	Parent     []ListParentNode `json:"parent"`
  	Navigation []ListNavNode    `json:"navigation"`
  	Pivots     []ListPivot      `json:"pivots"`
  	Details    ListDetails      `json:"details"`
  }
  
  // GetListConfig returns list configuration for the provided object type for the front-end application
  // or an error if it fails.

  func GetListConfig(db *sql.DB, objType string) (ListConfig, error) {

  	resp := newDefaultList(objType)
  	var err error
  
  	err = setListParams(db, &resp, objType)
  	resp.Navigation, err = getListNavigation(db, objType)
  	resp.Actions, err = getListActions(db, objType)
  	resp.Filters, err = getListFilters(db, objType)
  	resp.Options, err = getListOptions(db, objType)
  	resp.Parent, err = getListParent(db, objType)
  	resp.Graphs, err = getListGraph(db, objType)
  	resp.Pivots, err = getListPivot(db, objType)
  	resp.Details, err = getListDetails(db, objType)
  
  	if err != nil {
  		return ListConfig{}, err
  	}
  
  	return resp, nil
  }
  
  // GetListConfigObjectIDField takes in database connection and an object type and it returns the
  // ID field name for the provided object type.

  func GetListConfigObjectIDField(db *sql.DB, otype string) string {

  	var resp string

  	rows, err := db.Query(`SELECT

  		ID_FIELD
  		FROM LIST_CONFIG_ID_FIELD

  		WHERE OBJECT_TYPE = ` + fmt.Sprintf("'%s'", otype))

  	if err != nil {
  		return ""
  	}

  	defer rows.Close()

  	if rows.Next() {
  		rows.Scan(&resp)

  	}

  	if rows.Err() != nil {

  		return ""
  	}
  
  	return resp
  }
  
  // newDefaultList returns default configuration for the provided object type.
  func newDefaultList(objType string) ListConfig {
  	list := ListConfig{
  		ObjectType: objType,
  		Title:      objType,
  		LazyLoad:   false,
  		Options: ListOptions{
  			GlobalFilter:  true,
  			LocalFilters:  true,
  			RemoteFilters: false,
  			Pagination:    true,
  			PageSize:      20,
  		},
  		Filters: nil,
  		Actions: ListActions{
  			Create: false,
  			Update: false,
  			Delete: false,
  			Export: false,
  			Print:  false,
  			Graph:  false,
  		},
  		Parent:     nil,
  		Navigation: nil,
  	}
  
  	return list
  }
  
  // setListParams sets the default parameters of the provided configuration list for the provided object type.

  func setListParams(db *sql.DB, list *ListConfig, objType string) error {
  	rows, err := db.Query(`SELECT

  		OBJECT_TYPE, TITLE, LAZY_LOAD, INLINE_EDIT
  		FROM LIST_CONFIG

  		WHERE OBJECT_TYPE = ` + fmt.Sprintf("'%s'", objType))

  	if err != nil {
  		return err
  	}

  	defer rows.Close()
  	if rows.Next() {
  		otype, title := "", ""
  		lazyLoad, inlineEdit := 0, 0
  		rows.Scan(&otype, &title, &lazyLoad, &inlineEdit)

  		if otype != "" {
  			list.ObjectType = otype
  		}

  		if title != "" {
  			list.Title = title
  		}

  		list.LazyLoad = lazyLoad != 0
  		list.InlineEdit = inlineEdit != 0

  	}

  	if rows.Err() != nil {
  		return rows.Err()

  	}
  	return nil
  }
  
  // getListNavigation returns list navigation node slice for the provided objectType.

  func getListNavigation(db *sql.DB, listObjType string) ([]ListNavNode, error) {

  	resp := make([]ListNavNode, 0)

  	rows, err := db.Query(`SELECT
  		a.OBJECT_TYPE, a.PARENT_OBJECT_TYPE, a.LABEL, a.ICON, a.PARENT_FILTER_FIELD, b.PARENT_ID_FIELD

  		FROM LIST_CONFIG_NAVIGATION b
  		JOIN LIST_CONFIG_CHILD a ON b.PARENT_CHILD_ID = a.PARENT_CHILD_ID

  		WHERE b.LIST_OBJECT_TYPE = ` + fmt.Sprintf("'%s'", listObjType) +
  		` ORDER BY b.RB ASC`)

  	if err != nil {
  		return resp, err
  	}

  	defer rows.Close()

  	var node ListNavNode
  	for rows.Next() {
  		rows.Scan(&node.ObjectType, &node.ParentObjectType, &node.LabelField, &node.Icon,
  			&node.ParentFilterField, &node.ParentIDField)
  		resp = append(resp, node)

  	}

  	if rows.Err() != nil {
  		return nil, rows.Err()

  	}
  
  	return resp, nil
  }
  
  // getListActions returns list actions for the provided object type.

  func getListActions(db *sql.DB, objType string) (ListActions, error) {

  	var resp ListActions

  	rows, err := db.Query(`SELECT

  		ACTION_CREATE, ACTION_UPDATE, ACTION_DELETE, ACTION_EXPORT,
  		ACTION_PRINT, ACTION_GRAPH
  		FROM LIST_CONFIG

  		WHERE OBJECT_TYPE = ` + fmt.Sprintf("'%s'", objType))

  	if err != nil {
  		return ListActions{}, err
  	}

  	defer rows.Close()

  	var create, update, delete, export, print, graph uint32
  	if rows.Next() {
  		rows.Scan(&create, &update, &delete, &export, &print, &graph)
  		resp.Create = create != 0
  		resp.Update = update != 0
  		resp.Delete = delete != 0
  		resp.Export = export != 0
  		resp.Print = print != 0
  		resp.Graph = graph != 0

  	}

  	if rows.Err() != nil {
  		return ListActions{}, rows.Err()

  	}
  	return resp, nil
  }
  
  // getListFiters returns list filter slice for the provided object type.

  func getListFilters(db *sql.DB, objType string) ([]ListFilter, error) {

  	resp := make([]ListFilter, 0)
  	filtersFields, err := getFilterFieldsAndPosition(db, objType)
  	if err != nil {
  		return nil, err
  	}
  	for field, pos := range filtersFields {
  		filters, _ := getFiltersByFilterField(db, field)
  		for _, filter := range filters {
  			var f ListFilter
  			f.Position = pos
  			f.ObjectType = objType
  			f.FiltersField = field
  			f.DefaultValues = filter.DefaultValues
  			f.FiltersLabel = filter.Label
  			f.FiltersType = filter.Type
  			if filter.Type == "dropdown" {
  				f.DropdownConfig, err = getFilterDropdownConfig(db, field)
  				if err != nil {
  					return nil, err
  				}
  			}
  			resp = append(resp, f)
  		}
  	}
  
  	sortFilters(resp)
  
  	return resp, nil
  }
  
  // getFilterFieldsAndPosition returns a map of filter fields and their respective position in the menu.

  func getFilterFieldsAndPosition(db *sql.DB, objType string) (map[string]uint32, error) {

  	filtersField := make(map[string]uint32, 0)

  	rows, err := db.Query(`SELECT

  		FILTERS_FIELD, RB
  		FROM LIST_CONFIG_FILTERS

  		WHERE OBJECT_TYPE = ` + fmt.Sprintf("'%s'", objType))

  	if err != nil {
  		return nil, err
  	}

  	defer rows.Close()

  	for rows.Next() {
  		var field string
  		var rb uint32
  		rows.Scan(&field, &rb)
  		filtersField[field] = rb

  	}

  	if rows.Err() != nil {
  		return nil, rows.Err()

  	}
  	return filtersField, nil
  }
  
  type _filter struct {
  	DefaultValues string
  	Label         string
  	Type          string
  }
  
  // getFiltersByFilterField returns filter slice for the provided filter field.

  func getFiltersByFilterField(db *sql.DB, filtersField string) ([]_filter, error) {

  	resp := make([]_filter, 0)

  	rows, err := db.Query(`SELECT

  		FILTERS_TYPE, FILTERS_LABEL, DEFAULT_VALUES
  		FROM LIST_FILTERS_FIELD

  		WHERE FILTERS_FIELD = ` + fmt.Sprintf("'%s'", filtersField))

  	if err != nil {
  		return resp, err
  	}

  	defer rows.Close()

  	var f _filter
  	for rows.Next() {
  		rows.Scan(&f.Type, &f.Label, &f.DefaultValues)
  		resp = append(resp, f)

  	}

  	if rows.Err() != nil {
  		return resp, rows.Err()

  	}
  	return resp, nil
  }
  
  // getFilterDropdownConfig returns dropdown menu for the provided filter field.

  func getFilterDropdownConfig(db *sql.DB, filtersField string) (Dropdown, error) {

  	var resp Dropdown

  	rows, err := db.Query(`SELECT

  		FILTERS_FIELD, OBJECT_TYPE, ID_FIELD, LABEL_FIELD
  		FROM LIST_DROPDOWN_FILTER

  		WHERE FILTERS_FIELD = ` + fmt.Sprintf("'%s'", filtersField))

  	if err != nil {
  		return resp, err
  	}

  	defer rows.Close()
  	if rows.Next() {
  		rows.Scan(&resp.FiltersField, &resp.ObjectType, &resp.IDField, &resp.LabelField)

  	}

  	if rows.Err() != nil {
  		return resp, rows.Err()

  	}
  	return resp, nil
  }
  
  // sortFilters bubble sorts provided filters slice by position field.
  func sortFilters(filters []ListFilter) {
  	done := false
  	var temp ListFilter
  	for !done {
  		done = true
  		for i := 0; i < len(filters)-1; i++ {
  			if filters[i].Position > filters[i+1].Position {
  				done = false
  				temp = filters[i]
  				filters[i] = filters[i+1]
  				filters[i+1] = temp
  			}
  		}
  	}
  }
  
  // getListGraph return list graph slice for the provided object type.

  func getListGraph(db *sql.DB, objType string) ([]ListGraph, error) {

  	resp := make([]ListGraph, 0)

  	rows, err := db.Query(`SELECT

  		OBJECT_TYPE, X_FIELD, Y_FIELD, GROUP_FIELD, LABEL
  		FROM LIST_GRAPHS

  		WHERE OBJECT_TYPE = ` + fmt.Sprintf("'%s'", objType))

  	if err != nil {
  		return resp, err
  	}

  	defer rows.Close()

  	var lg ListGraph
  	for rows.Next() {
  		rows.Scan(&lg.ObjectType, &lg.X, &lg.Y, &lg.GroupField, &lg.Label)
  		resp = append(resp, lg)

  	}

  	if rows.Err() != nil {
  		return resp, rows.Err()

  	}
  	return resp, nil
  }
  
  // getListOptions returns list options for the provided object type.

  func getListOptions(db *sql.DB, objType string) (ListOptions, error) {

  	var resp ListOptions

  	rows, err := db.Query(`SELECT

  		GLOBAL_FILTER, LOCAL_FILTER, REMOTE_FILTER, PAGINATION,
  		PAGE_SIZE, PIVOT, DETAIL, TOTAL
  		FROM LIST_CONFIG

  		WHERE OBJECT_TYPE = ` + fmt.Sprintf("'%s'", objType))

  	if err != nil {
  		return ListOptions{}, err
  	}

  	defer rows.Close()
  	if rows.Next() {
  		var gfilter, lfilters, rfilters, pagination, pageSize, pivot, detail, total uint32
  		rows.Scan(&gfilter, &lfilters, &rfilters, &pagination, &pageSize, &pivot, &detail, &total)
  		resp.GlobalFilter = gfilter != 0
  		resp.LocalFilters = lfilters != 0
  		resp.RemoteFilters = rfilters != 0
  		resp.Pagination = pagination != 0
  		resp.PageSize = pageSize
  		resp.Pivot = pivot != 0
  		resp.Detail = detail != 0
  		resp.Total = total != 0
  	}
  	if rows.Err() != nil {
  		return ListOptions{}, rows.Err()

  	}
  	return resp, nil
  }
  
  // getListParent returns list parent node slice for the provided object type.

  func getListParent(db *sql.DB, objType string) ([]ListParentNode, error) {

  	resp := make([]ListParentNode, 0)

  	rows, err := db.Query(`SELECT

  		PARENT_OBJECT_TYPE, PARENT_LABEL_FIELD, PARENT_FILTER_FIELD
  		FROM LIST_CONFIG_CHILD

  		WHERE OBJECT_TYPE = ` + fmt.Sprintf("'%s'", objType))

  	if err != nil {
  		return resp, err
  	}

  	defer rows.Close()

  	var pnode ListParentNode
  	for rows.Next() {
  		rows.Scan(&pnode.ObjectType, &pnode.LabelField, &pnode.FilterField)
  		resp = append(resp, pnode)

  	}

  	if rows.Err() != nil {
  		return nil, rows.Err()

  	}
  
  	return resp, nil
  }
  
  // getListPivot list pivot slice for the provided object type.

  func getListPivot(db *sql.DB, objType string) ([]ListPivot, error) {

  	resp := make([]ListPivot, 0)

  	rows, err := db.Query(`SELECT

  		OBJECT_TYPE, GROUP_FIELD, DISTINCT_FIELD, VALUE_FIELD
  		FROM LIST_PIVOTS

  		WHERE OBJECT_TYPE = ` + fmt.Sprintf("'%s'", objType))

  	if err != nil {
  		return resp, err
  	}

  	defer rows.Close()

  	var p ListPivot
  	for rows.Next() {
  		rows.Scan(&p.ObjectType, &p.GroupField, &p.DistinctField, &p.Value)
  		resp = append(resp, p)

  	}

  	if rows.Err() != nil {
  		return nil, rows.Err()

  	}
  
  	return resp, nil
  }
  
  // getListDetails returns list details for the provided object type.

  func getListDetails(db *sql.DB, objType string) (ListDetails, error) {

  	var resp ListDetails

  	rows, err := db.Query(`SELECT

  		OBJECT_TYPE, PARENT_OBJECT_TYPE, PARENT_FILTER_FIELD, SINGLE_DETAIL
  		FROM LIST_CONFIG_DETAIL

  		WHERE PARENT_OBJECT_TYPE = ` + fmt.Sprintf("'%s'", objType))

  	if err != nil {
  		return resp, err
  	}

  	defer rows.Close()
  	if rows.Next() {
  		var singleDetail uint32
  		rows.Scan(&resp.ObjectType, &resp.ParentObjectType, &resp.ParentFilterField, &singleDetail)
  		resp.SingleDetail = singleDetail != 0

  	}

  	if rows.Err() != nil {
  		return resp, rows.Err()

  	}
  
  	return resp, nil
  }