package seo

import (
	"context"
	"fmt"
	"strings"

	"git.golem15.com/golem15/sm-seo-plugin/classes"
	"git.golem15.com/golem15/sm-seo-plugin/controllers"
	"git.golem15.com/golem15/summercms/modules/pact"
	"git.golem15.com/golem15/summercms/modules/signpost"
)

// TabSEO is the key of the SEO tab added to every content type's form.
const TabSEO = "golem15.seo::lang.tab.seo"

// AdminActionExtensions adds the SEO tab (D-01, D-91) to the admin form of
// every content type registered in signpost with a content descriptor that
// names a controller. The content plugins import nothing from this plugin.
func (p *Plugin) AdminActionExtensions() []pact.AdminActionExtension {
	reg := p.registry()
	if reg == nil {
		return nil
	}
	var out []pact.AdminActionExtension
	types := reg.ContentTypes()
	for _, typ := range types {
		if typ.Content == nil || strings.TrimSpace(typ.Content.Controller) == "" {
			continue
		}
		out = append(out, pact.AdminActionExtension{
			Controller: typ.Content.Controller,
			Form:       p.seoTab(typ.Key),
		})
	}
	if form := p.typeSettingsTabs(types); form != nil {
		out = append(out, pact.AdminActionExtension{Controller: controllers.SettingsControllerID, Form: form})
	}
	return out
}

func (p *Plugin) registry() *signpost.Registry {
	if p == nil || p.app == nil {
		return nil
	}
	reg, _ := p.app.Lookup[*signpost.Registry]()
	return reg
}

// seoTabYAML is the SEO tab's fields document: the tab placed after the
// owner's tabs (no anchor) and its fields.
const seoTabYAML = `tabs:
    - name: golem15.seo::lang.tab.seo
fields:
    seo_title:
        label: golem15.seo::lang.field.title
        type: mltext
        tab: golem15.seo::lang.tab.seo
`

// seoTab is the form extension of content type key.
func (p *Plugin) seoTab(key string) *pact.AdminFormExtension {
	return &pact.AdminFormExtension{
		FieldsYAML:  []byte(seoTabYAML),
		Permissions: []string{controllers.PermissionManage},
		Visible: func(ctx context.Context) bool {
			return p.injected(ctx, key)
		},
		Load: func(ctx context.Context, in pact.AdminFormLoad) (map[string]any, error) {
			return p.loadSEOTab(ctx, key, in)
		},
		Save: func(ctx context.Context, in pact.AdminFormSave) (pact.AdminFormSaveResult, error) {
			return p.saveSEOTab(ctx, key, in)
		},
	}
}

// contentType returns the registered content type key with a descriptor.
func (p *Plugin) contentType(key string) (pact.MenuItemType, error) {
	reg := p.registry()
	if reg == nil {
		return pact.MenuItemType{}, fmt.Errorf("golem15.seo: menu item type registry is not published")
	}
	typ, ok := reg.ContentType(key)
	if !ok {
		return pact.MenuItemType{}, fmt.Errorf("golem15.seo: content type %q is not registered", key)
	}
	return typ, nil
}

// loadSEOTab returns the stored SEO tab values of a record, every field a
// map of locale to text.
func (p *Plugin) loadSEOTab(ctx context.Context, key string, in pact.AdminFormLoad) (map[string]any, error) {
	svc := p.Service()
	if svc == nil {
		return nil, classes.ErrNotBooted
	}
	typ, err := p.contentType(key)
	if err != nil {
		return nil, err
	}
	entries, err := classes.LoadEntries(in.DB.WithContext(ctx), typ.Content.Model, in.ID)
	if err != nil {
		return nil, err
	}
	out := map[string]any{}
	for column, perLocale := range classes.RecordValuesOf(entries) {
		out[classes.FieldPrefix+column] = perLocale
	}
	return out, nil
}

// saveSEOTab stores the submitted SEO tab values of a record inside the
// record's save transaction.
func (p *Plugin) saveSEOTab(ctx context.Context, key string, in pact.AdminFormSave) (pact.AdminFormSaveResult, error) {
	svc := p.Service()
	if svc == nil {
		return pact.AdminFormSaveResult{}, classes.ErrNotBooted
	}
	typ, err := p.contentType(key)
	if err != nil {
		return pact.AdminFormSaveResult{}, err
	}
	values := classes.RecordValues{}
	for _, column := range classes.EntryColumns {
		raw, ok := in.Values[classes.FieldPrefix+column]
		if !ok {
			continue
		}
		values[column] = localeMap(raw)
	}
	if _, _, err := svc.SaveRecord(ctx, in.DB, classes.RecordWrite{Type: typ, ID: in.ID, Values: values}); err != nil {
		return pact.AdminFormSaveResult{}, err
	}
	return pact.AdminFormSaveResult{}, nil
}

// localeMap reads a submitted value as locale -> text: a translatable
// field's map, or a plain string under the empty locale key.
func localeMap(raw any) map[string]string {
	switch v := raw.(type) {
	case map[string]string:
		return v
	case map[string]any:
		out := make(map[string]string, len(v))
		for locale, value := range v {
			if s, ok := value.(string); ok {
				out[locale] = s
			}
		}
		return out
	case string:
		return map[string]string{"": v}
	}
	return map[string]string{}
}

// injected reports whether the SEO tab of content type key is shown: false
// only when its settings row turns it off. It answers true when it cannot
// decide, so a database error never hides stored values.
func (p *Plugin) injected(ctx context.Context, key string) bool {
	svc := p.Service()
	if svc == nil {
		return true
	}
	db, err := svc.DB(ctx)
	if err != nil {
		return true
	}
	row, err := classes.LoadTypeSetting(db, key)
	if err != nil {
		return true
	}
	return row.Inject
}