package cabana

import (
	"context"
	"encoding/json"
	"fmt"
	"reflect"
	"sort"
	"strings"

	"git.golem15.com/golem15/summercms/modules/phrasebook"
)

// MessageForms is one controller message resolved to its CLDR plural forms
// (D-13). "other" is always present; the SPA picks a form with
// Intl.PluralRules and interpolates :count, :name and :term (D-24).
type MessageForms map[string]string

// MarshalJSON keeps an unset message an object, never null.
func (m MessageForms) MarshalJSON() ([]byte, error) {
	if m == nil {
		return []byte("{}"), nil
	}
	return json.Marshal(map[string]string(m))
}

// listMessageKeys is the config_list.yaml messages block: phrase keys.
type listMessageKeys struct {
	RecordCount     string `yaml:"recordCount"`
	Create          string `yaml:"create"`
	SearchPrompt    string `yaml:"searchPrompt"`
	Empty           string `yaml:"empty"`
	EmptySearch     string `yaml:"emptySearch"`
	EmptySearchHint string `yaml:"emptySearchHint"`
	Selected        string `yaml:"selected"`
	DeleteSelected  string `yaml:"deleteSelected"`
	DeleteConfirm   string `yaml:"deleteConfirm"`
	Deleted         string `yaml:"deleted"`
}

// ListMessages is a list schema's copy, every key resolved (same field order
// as listMessageKeys).
type ListMessages struct {
	RecordCount     MessageForms `json:"recordCount"`
	Create          MessageForms `json:"create"`
	SearchPrompt    MessageForms `json:"searchPrompt"`
	Empty           MessageForms `json:"empty"`
	EmptySearch     MessageForms `json:"emptySearch"`
	EmptySearchHint MessageForms `json:"emptySearchHint"`
	Selected        MessageForms `json:"selected"`
	DeleteSelected  MessageForms `json:"deleteSelected"`
	DeleteConfirm   MessageForms `json:"deleteConfirm"`
	Deleted         MessageForms `json:"deleted"`
}

// formMessageKeys is the config_form.yaml messages block: phrase keys.
type formMessageKeys struct {
	Create        string `yaml:"create"`
	Update        string `yaml:"update"`
	Saved         string `yaml:"saved"`
	DeleteConfirm string `yaml:"deleteConfirm"`
	Deleted       string `yaml:"deleted"`
}

// FormMessages is a form's copy, every key resolved.
type FormMessages struct {
	Create        MessageForms `json:"create"`
	Update        MessageForms `json:"update"`
	Saved         MessageForms `json:"saved"`
	DeleteConfirm MessageForms `json:"deleteConfirm"`
	Deleted       MessageForms `json:"deleted"`
}

// relationMessageKeys is one config_relation.yaml relation's messages block.
type relationMessageKeys struct {
	Link            string `yaml:"link"`
	LinkHint        string `yaml:"linkHint"`
	CandidateSearch string `yaml:"candidateSearch"`
	Linked          string `yaml:"linked"`
	UnlinkSelected  string `yaml:"unlinkSelected"`
	UnlinkConfirm   string `yaml:"unlinkConfirm"`
	Unlinked        string `yaml:"unlinked"`
	Empty           string `yaml:"empty"`
	// The child create, update and delete copy and the pivot copy (12.2).
	Create           string `yaml:"create"`
	CreateTitle      string `yaml:"createTitle"`
	UpdateTitle      string `yaml:"updateTitle"`
	PreviewTitle     string `yaml:"previewTitle"`
	Created          string `yaml:"created"`
	Updated          string `yaml:"updated"`
	DeleteSelected   string `yaml:"deleteSelected"`
	DeleteConfirm    string `yaml:"deleteConfirm"`
	DeleteOneConfirm string `yaml:"deleteOneConfirm"`
	Deleted          string `yaml:"deleted"`
	PivotTitle       string `yaml:"pivotTitle"`
	PivotSaved       string `yaml:"pivotSaved"`
	EditPivot        string `yaml:"editPivot"`
	CreateSubmit     string `yaml:"createSubmit"`
	UpdateSubmit     string `yaml:"updateSubmit"`
	PivotSubmit      string `yaml:"pivotSubmit"`
	LinkSubmit       string `yaml:"linkSubmit"`
}

// RelationMessages is a relation manager's copy, every key resolved.
type RelationMessages struct {
	Link             MessageForms `json:"link"`
	LinkHint         MessageForms `json:"linkHint"`
	CandidateSearch  MessageForms `json:"candidateSearch"`
	Linked           MessageForms `json:"linked"`
	UnlinkSelected   MessageForms `json:"unlinkSelected"`
	UnlinkConfirm    MessageForms `json:"unlinkConfirm"`
	Unlinked         MessageForms `json:"unlinked"`
	Empty            MessageForms `json:"empty"`
	Create           MessageForms `json:"create"`
	CreateTitle      MessageForms `json:"createTitle"`
	UpdateTitle      MessageForms `json:"updateTitle"`
	PreviewTitle     MessageForms `json:"previewTitle"`
	Created          MessageForms `json:"created"`
	Updated          MessageForms `json:"updated"`
	DeleteSelected   MessageForms `json:"deleteSelected"`
	DeleteConfirm    MessageForms `json:"deleteConfirm"`
	DeleteOneConfirm MessageForms `json:"deleteOneConfirm"`
	Deleted          MessageForms `json:"deleted"`
	PivotTitle       MessageForms `json:"pivotTitle"`
	PivotSaved       MessageForms `json:"pivotSaved"`
	EditPivot        MessageForms `json:"editPivot"`
	CreateSubmit     MessageForms `json:"createSubmit"`
	UpdateSubmit     MessageForms `json:"updateSubmit"`
	PivotSubmit      MessageForms `json:"pivotSubmit"`
	LinkSubmit       MessageForms `json:"linkSubmit"`
}

// Framework defaults (D-13): every omitted key falls back to backend::lang.
var (
	listMessageDefaults = listMessageKeys{
		RecordCount:     "backend::lang.messages.list.record_count",
		Create:          "backend::lang.messages.list.create",
		SearchPrompt:    "backend::lang.list.search_prompt",
		Empty:           "backend::lang.list.no_records",
		EmptySearch:     "backend::lang.messages.list.empty_search",
		EmptySearchHint: "backend::lang.messages.list.empty_search_hint",
		Selected:        "backend::lang.messages.list.selected",
		DeleteSelected:  "backend::lang.list.delete_selected",
		DeleteConfirm:   "backend::lang.messages.list.delete_confirm",
		Deleted:         "backend::lang.messages.list.deleted",
	}
	formMessageDefaults = formMessageKeys{
		Create:        "backend::lang.messages.form.create",
		Update:        "backend::lang.messages.form.update",
		Saved:         "backend::lang.messages.form.saved",
		DeleteConfirm: "backend::lang.messages.form.delete_confirm",
		Deleted:       "backend::lang.messages.form.deleted",
	}
	relationMessageDefaults = relationMessageKeys{
		Link:             "backend::lang.messages.relation.link",
		LinkHint:         "backend::lang.messages.relation.link_hint",
		CandidateSearch:  "backend::lang.messages.relation.candidate_search",
		Linked:           "backend::lang.messages.relation.linked",
		UnlinkSelected:   "backend::lang.messages.relation.unlink_selected",
		UnlinkConfirm:    "backend::lang.messages.relation.unlink_confirm",
		Unlinked:         "backend::lang.messages.relation.unlinked",
		Empty:            "backend::lang.messages.relation.empty",
		Create:           "backend::lang.messages.relation.create",
		CreateTitle:      "backend::lang.messages.relation.create_title",
		UpdateTitle:      "backend::lang.messages.relation.update_title",
		PreviewTitle:     "backend::lang.messages.relation.preview_title",
		Created:          "backend::lang.messages.relation.created",
		Updated:          "backend::lang.messages.relation.updated",
		DeleteSelected:   "backend::lang.messages.relation.delete_selected",
		DeleteConfirm:    "backend::lang.messages.relation.delete_confirm",
		DeleteOneConfirm: "backend::lang.messages.relation.delete_one_confirm",
		Deleted:          "backend::lang.messages.relation.deleted",
		PivotTitle:       "backend::lang.messages.relation.pivot_title",
		PivotSaved:       "backend::lang.messages.relation.pivot_saved",
		EditPivot:        "backend::lang.messages.relation.edit_pivot",
		CreateSubmit:     "backend::lang.messages.relation.create_submit",
		UpdateSubmit:     "backend::lang.messages.relation.update_submit",
		PivotSubmit:      "backend::lang.messages.relation.pivot_submit",
		LinkSubmit:       "backend::lang.messages.relation.link_submit",
	}
)

// withDefaults fills every empty key of keys from defaults.
func withDefaults[K any](keys, defaults K) K {
	out := keys
	dst := reflect.ValueOf(&out).Elem()
	src := reflect.ValueOf(defaults)
	for i := 0; i < dst.NumField(); i++ {
		if dst.Field(i).String() == "" {
			dst.Field(i).SetString(src.Field(i).String())
		}
	}
	return out
}

// messageKeyPairs lists (yaml name, phrase key) for every key, in field order.
func messageKeyPairs[K any](keys K) [][2]string {
	v := reflect.ValueOf(keys)
	t := v.Type()
	out := make([][2]string, 0, t.NumField())
	for i := 0; i < t.NumField(); i++ {
		out = append(out, [2]string{t.Field(i).Tag.Get("yaml"), v.Field(i).String()})
	}
	return out
}

// localizeMessages resolves each key of K into the same-index MessageForms
// field of M. Without a translator, or for a key that cannot convert, the
// form is {"other": text} where text is the translation or the key itself.
func localizeMessages[K any, M any](ctx context.Context, tr *phrasebook.Translator, keys K) M {
	var out M
	dst := reflect.ValueOf(&out).Elem()
	src := reflect.ValueOf(keys)
	locale := schemaLocale(ctx, tr)
	for i := 0; i < src.NumField(); i++ {
		key := src.Field(i).String()
		dst.Field(i).Set(reflect.ValueOf(messageForms(tr, locale, key)))
	}
	return out
}

func messageForms(tr *phrasebook.Translator, locale, key string) MessageForms {
	if key == "" {
		return MessageForms{"other": ""}
	}
	if tr == nil {
		return MessageForms{"other": key}
	}
	if forms, ok := tr.Forms(locale, key); ok {
		return MessageForms(forms)
	}
	return MessageForms{"other": tr.GetIn(locale, key, nil)}
}

// listMessageKeySet is the list's resolved key set: declared keys over the
// framework defaults, with searchPrompt and empty defaulting to the list's own
// toolbar.search.prompt and noRecordsMessage when those are set.
func (s *ListSchema) listMessageKeySet() listMessageKeys {
	defaults := listMessageDefaults
	if s.SearchPrompt != "" {
		defaults.SearchPrompt = s.SearchPrompt
	}
	if s.NoRecordsMessage != "" {
		defaults.Empty = s.NoRecordsMessage
	}
	return withDefaults(s.messageKeys, defaults)
}

// formMessageKeySet is the form's resolved key set; create defaults to the
// config_form.yaml name when it is set.
func (s *FormSchema) formMessageKeySet() formMessageKeys {
	defaults := formMessageDefaults
	if s.Name != "" {
		defaults.Create = s.Name
	}
	return withDefaults(s.messageKeys, defaults)
}

func (s *RelationSchema) relationMessageKeySet() relationMessageKeys {
	return withDefaults(s.messageKeys, relationMessageDefaults)
}

// validateMessageKeys fails activation when a controller's messages block (or
// a framework default) names a phrase key no locale defines (D-13). Defaults
// taken from the list's own search prompt, empty message or the form name are
// Winter strings that may be literal text, so they are not checked.
func validateMessageKeys(reg *Registry, tr *phrasebook.Translator) error {
	if reg == nil || tr == nil {
		return nil
	}
	ids := make([]string, 0, len(reg.byID))
	for id := range reg.byID {
		ids = append(ids, id)
	}
	sort.Strings(ids)
	check := func(pluginID, id, file string, pairs [][2]string) error {
		for _, pair := range pairs {
			if pair[1] != "" && !tr.Has(pair[1]) {
				return bootErr(pluginID, id, file, fmt.Errorf("messages.%s names missing phrase key %s", pair[0], pair[1]))
			}
		}
		return nil
	}
	for _, id := range ids {
		cc := reg.byID[id]
		if cc.List != nil {
			if err := check(cc.PluginID, id, "config_list.yaml", messageKeyPairs(withDefaults(cc.List.messageKeys, listMessageDefaults))); err != nil {
				return err
			}
		}
		if cc.Form != nil {
			if err := check(cc.PluginID, id, "config_form.yaml", messageKeyPairs(withDefaults(cc.Form.messageKeys, formMessageDefaults))); err != nil {
				return err
			}
		}
		actionNames := make([]string, 0, len(cc.Actions))
		for name := range cc.Actions {
			actionNames = append(actionNames, name)
		}
		sort.Strings(actionNames)
		for _, name := range actionNames {
			// A label with a namespace separator is a phrase key and must
			// resolve; anything else is literal button text.
			if label := cc.Actions[name].Label; strings.Contains(label, "::") && !tr.Has(label) {
				return fmt.Errorf("cabana: admin controller %s/%s: action %s label names missing phrase key %s", cc.PluginID, id, name, label)
			}
		}
		names := make([]string, 0, len(cc.Relations))
		for name := range cc.Relations {
			names = append(names, name)
		}
		sort.Strings(names)
		for _, name := range names {
			if schema := cc.Relations[name].Schema; schema != nil {
				if err := check(cc.PluginID, id, "config_relation.yaml", messageKeyPairs(schema.relationMessageKeySet())); err != nil {
					return fmt.Errorf("relation %s: %w", name, err)
				}
			}
		}
	}
	return nil
}