package cabana

import (
	"context"
	"encoding/json"
	"fmt"
)

// ListSort is the compiled default sort. Direction is exactly asc or desc.
type ListSort struct {
	Column    string `json:"column"`
	Direction string `json:"direction"`
}

// ListColumn is one compiled columns.yaml entry, in file order.
// Omitted sortable defaults to true, matching Winter; searchable defaults to false.
type ListColumn struct {
	Key        string `json:"key"`
	Label      string `json:"label"`
	Searchable bool   `json:"searchable"`
	Sortable   bool   `json:"sortable"`
	Type       string `json:"type,omitempty"`
	Relation   string `json:"relation,omitempty"`
	Select     string `json:"select,omitempty"`
}

// ListFilter is one compiled config_filter scope. Values stay typed scalars.
type ListFilter struct {
	Name       string       `json:"name"`
	Label      string       `json:"label,omitempty"`
	Type       string       `json:"type"`
	Column     string       `json:"column,omitempty"`
	Scope      string       `json:"scope,omitempty"`
	ModelClass string       `json:"modelClass,omitempty"`
	NameFrom   string       `json:"nameFrom,omitempty"`
	TrueValue  *jsonScalar  `json:"trueValue,omitempty"`
	FalseValue *jsonScalar  `json:"falseValue,omitempty"`
	Options    []FormOption `json:"options,omitempty"`
}

// RowAction is a per-record link derived from recordUrl.
type RowAction struct {
	Name  string `json:"name"`
	Label string `json:"label,omitempty"`
	URL   string `json:"url,omitempty"`
}

// BulkAction is a checkbox action. It carries no SQL.
type BulkAction struct {
	Name  string `json:"name"`
	Label string `json:"label,omitempty"`
}

// ListSchema is the boot-compiled list contract for one controller.
// Labels stay as source keys until a request localizes a copy.
type ListSchema struct {
	Title            string       `json:"title,omitempty"`
	ModelClass       string       `json:"modelClass,omitempty"`
	RecordURL        string       `json:"recordUrl,omitempty"`
	NoRecordsMessage string       `json:"noRecordsMessage,omitempty"`
	RecordsPerPage   int          `json:"recordsPerPage"`
	PerPageOptions   []int        `json:"perPageOptions"`
	ShowSearch       bool         `json:"showSearch"`
	ShowSetup        bool         `json:"showSetup"`
	ShowCheckboxes   bool         `json:"showCheckboxes"`
	ShowSorting      bool         `json:"showSorting"`
	SearchTerm       string       `json:"searchTerm"`
	SearchPrompt     string       `json:"searchPrompt,omitempty"`
	DefaultSort      *ListSort    `json:"defaultSort,omitempty"`
	ToolbarButtons   []string     `json:"toolbarButtons"`
	Columns          []ListColumn `json:"columns"`
	Filters          []ListFilter `json:"filters"`
	RowActions       []RowAction  `json:"rowActions"`
	BulkActions      []BulkAction `json:"bulkActions"`
	// Messages is the list's copy (D-13). The cached schema carries each
	// phrase key as its own form; a response resolves them in its locale.
	Messages *ListMessages `json:"messages"`
	Meta     *FormMeta     `json:"meta,omitempty"`

	messageKeys listMessageKeys
}

// MarshalJSON keeps omitted collections as arrays so a partial copy cannot emit null.
func (s ListSchema) MarshalJSON() ([]byte, error) {
	if s.Messages == nil {
		keys := localizeMessages[listMessageKeys, ListMessages](context.Background(), nil, s.listMessageKeySet())
		s.Messages = &keys
	}
	type alias ListSchema
	out := alias(s)
	if out.PerPageOptions == nil {
		out.PerPageOptions = []int{}
	}
	if out.ToolbarButtons == nil {
		out.ToolbarButtons = []string{}
	}
	if out.Columns == nil {
		out.Columns = []ListColumn{}
	}
	if out.Filters == nil {
		out.Filters = []ListFilter{}
	}
	if out.RowActions == nil {
		out.RowActions = []RowAction{}
	}
	if out.BulkActions == nil {
		out.BulkActions = []BulkAction{}
	}
	return json.Marshal(out)
}

// FormSchema is the locale-neutral form contract compiled once at boot.
// Display strings stay as source keys until a request localizes a copy.
type FormSchema struct {
	Name       string      `json:"name,omitempty"`
	ModelClass string      `json:"modelClass,omitempty"`
	Fields     []FormField `json:"fields"`

	messageKeys formMessageKeys
	redirects   FormRedirects
}

// FormView is one request's localized form, including the locale actually used.
type FormView struct {
	Name       string      `json:"name,omitempty"`
	ModelClass string      `json:"modelClass,omitempty"`
	Fields     []FormField `json:"fields"`
	// Messages is the form's copy resolved in the request locale (D-13).
	Messages FormMessages `json:"messages"`
	// Redirects are the raw Winter config_form.yaml targets; the SPA maps
	// them onto its routes.
	Redirects FormRedirects `json:"redirects"`
	Meta      FormMeta      `json:"meta"`
}

// FormRedirects are config_form.yaml defaultRedirect, create.* and update.*.
type FormRedirects struct {
	Default string       `json:"default"`
	Create  FormRedirect `json:"create"`
	Update  FormRedirect `json:"update"`
}

// FormRedirect is one Winter redirect pair.
type FormRedirect struct {
	Redirect      string `json:"redirect"`
	RedirectClose string `json:"redirectClose"`
}

// FormMeta reports the locale selected for a schema response.
type FormMeta struct {
	Locale string `json:"locale"`
}

// FormField is one Winter field in source order. JSON keys keep Winter spelling.
type FormField struct {
	Name        string                `json:"name"`
	Type        string                `json:"type"`
	Label       string                `json:"label,omitempty"`
	Comment     string                `json:"comment,omitempty"`
	Span        string                `json:"span,omitempty"`
	Tab         string                `json:"tab,omitempty"`
	Size        string                `json:"size,omitempty"`
	Context     *fieldContext         `json:"context,omitempty"`
	NameFrom    string                `json:"nameFrom,omitempty"`
	EmptyOption string                `json:"emptyOption,omitempty"`
	Relation    string                `json:"relation,omitempty"`
	Multiple    bool                  `json:"multiple,omitempty"`
	ReadOnly    bool                  `json:"readOnly,omitempty"`
	Required    bool                  `json:"required,omitempty"`
	Default     *jsonScalar           `json:"default,omitempty"`
	Attributes  map[string]jsonScalar `json:"attributes,omitempty"`
	Options     []FormOption          `json:"options,omitempty"`

	optionsMethod string
}

// FormOption is one dropdown choice. Value keeps the YAML scalar's JSON type.
type FormOption struct {
	Value jsonScalar `json:"value"`
	Label string     `json:"label"`
}

// jsonScalar is a JSON scalar that still emits false, 0, and empty string.
type jsonScalar struct {
	raw json.RawMessage
}

func (s jsonScalar) MarshalJSON() ([]byte, error) {
	if len(s.raw) == 0 {
		return []byte("null"), nil
	}
	return s.raw, nil
}

// UnmarshalJSON accepts exactly a JSON scalar (string, number, boolean or
// null), so a served schema decodes back into its documented type.
func (s *jsonScalar) UnmarshalJSON(raw []byte) error {
	var value any
	if err := json.Unmarshal(raw, &value); err != nil {
		return err
	}
	switch value.(type) {
	case nil:
		s.raw = nil
	case string, float64, bool:
		s.raw = append(json.RawMessage(nil), raw...)
	default:
		return fmt.Errorf("cabana: %s is not a JSON scalar", raw)
	}
	return nil
}

// fieldContext preserves a single Winter context string or a source-ordered list.
type fieldContext struct {
	single bool
	values []string
}

// UnmarshalJSON accepts the two served shapes: a string or a string list.
func (c *fieldContext) UnmarshalJSON(raw []byte) error {
	var single string
	if err := json.Unmarshal(raw, &single); err == nil {
		*c = fieldContext{single: true, values: []string{single}}
		return nil
	}
	var values []string
	if err := json.Unmarshal(raw, &values); err != nil {
		return fmt.Errorf("cabana: context must be a string or a list of strings")
	}
	*c = fieldContext{values: values}
	return nil
}

func (c fieldContext) MarshalJSON() ([]byte, error) {
	if c.single {
		text := ""
		if len(c.values) > 0 {
			text = c.values[0]
		}
		return json.Marshal(text)
	}
	values := c.values
	if values == nil {
		values = []string{}
	}
	return json.Marshal(values)
}