// Package controllers holds the sitemap plugin's admin controllers.
package controllers

import (
	"context"
	"errors"
	"fmt"
	"strings"

	"git.golem15.com/golem15/sm-sitemap-plugin/classes"
	"git.golem15.com/golem15/sm-sitemap-plugin/models"
	"git.golem15.com/golem15/summercms/modules/backpack"
	"git.golem15.com/golem15/summercms/modules/cabana"
	"git.golem15.com/golem15/summercms/modules/pact"
	"git.golem15.com/golem15/summercms/modules/signpost"
	"gorm.io/gorm"
)

const (
	// DefinitionsControllerID is the cabana controller id of the sitemap
	// definition form.
	DefinitionsControllerID = "golem15.sitemap.definitions"
	// PermissionAccessDefinitions is Definitions::$requiredPermissions.
	PermissionAccessDefinitions = "golem15.sitemap.access_definitions"
)

// typeURLLabel is the label of the built-in url item type.
const typeURLLabel = "golem15.sitemap::lang.item.url"

// The phrase keys of the item row refusals.
const (
	errURLScheme  = "golem15.sitemap::lang.errors.url_scheme"
	errURLPattern = "golem15.sitemap::lang.errors.url_pattern"
	errReference  = "golem15.sitemap::lang.item.reference_required"
)

// definitionsAdminController edits the one sitemap definition of the
// application (theme default): a singleton form whose items are a repeater
// with a type dropdown (url plus the registry types) and a reference
// dropdown that depends on it.
type definitionsAdminController struct {
	app func() *backpack.App
}

func (definitionsAdminController) ID() string { return DefinitionsControllerID }

func (definitionsAdminController) ModelName() string { return `Golem15\Sitemap\Models\Definition` }

func (definitionsAdminController) ConfigDir() string { return "controllers/definitions" }

func (definitionsAdminController) RequiredPermissions() []string {
	return []string{PermissionAccessDefinitions}
}

func (definitionsAdminController) NewRecord() any { return &models.Definition{} }

// The singleton record is the definition with the fixed theme key, created
// with no items when there is none (PHP index(): firstOrCreate, then the
// update form).
func (definitionsAdminController) SingletonRecord(_ context.Context, db *gorm.DB) (any, error) {
	if db == nil {
		return nil, errors.New("golem15.sitemap: database is not configured")
	}
	var defs []models.Definition
	if err := db.Where("theme = ?", models.DefinitionTheme).Order("id ASC").Limit(1).Find(&defs).Error; err != nil {
		return nil, err
	}
	if len(defs) > 0 {
		return &defs[0], nil
	}
	theme := models.DefinitionTheme
	def := &models.Definition{Theme: &theme}
	def.SetItems(nil)
	if err := db.Create(def).Error; err != nil {
		return nil, err
	}
	return def, nil
}

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

// DropdownOptions serves the item type dropdown: url, then every registry
// type in registry order with its label (PHP getTypeOptions).
func (c definitionsAdminController) DropdownOptions(string) []pact.Option {
	out := []pact.Option{{Value: models.ItemTypeURL, Label: typeURLLabel}}
	for _, t := range c.registry().Types() {
		out = append(out, pact.Option{Value: t.Key, Label: t.Label})
	}
	return out
}

// DependentOptions serves the reference dropdown of an item row: the
// references of the row's type through signpost.ReferenceOptions; url and a
// type without references answer Applies false.
func (c definitionsAdminController) DependentOptions(ctx context.Context, _ string, values map[string]any) (pact.DependentOptionSet, error) {
	typ, _ := values["type"].(string)
	return signpost.ReferenceOptions(ctx, c.registry(), typ)
}

// FormBeforeCreate checks the item rows (see checkItems).
func (c definitionsAdminController) FormBeforeCreate(_ context.Context, model any) error {
	return c.checkItems(model)
}

// FormBeforeUpdate checks the item rows (see checkItems).
func (c definitionsAdminController) FormBeforeUpdate(_ context.Context, model any) error {
	return c.checkItems(model)
}

// checkItems refuses, per row, a url outside classes.AllowedItemURL
// (data.<i>.url), a URL pattern that is not a path
// (signpost.ValidItemPattern, data.<i>.urlPattern) and a missing reference
// for a registry type that takes one (data.<i>.reference). The PHP plugin
// checked none of them: a javascript: URL would reach <loc>, which
// sitemap.xsl renders as a link, and a row without its reference resolves to
// nothing and is left out of the sitemap without a word.
func (c definitionsAdminController) checkItems(model any) error {
	def, ok := model.(*models.Definition)
	if !ok || def == nil {
		return nil
	}
	reg := c.registry()
	details := map[string]any{}
	for i, item := range def.Items() {
		if item.Type != models.ItemTypeURL {
			if t, known := reg.Type(item.Type); known && t.References != nil && strings.TrimSpace(models.Text(item.Reference)) == "" {
				details[fmt.Sprintf("data.%d.reference", i)] = []string{errReference}
			}
		}
		if !classes.AllowedItemURL(models.Text(item.URL)) {
			details[fmt.Sprintf("data.%d.url", i)] = []string{errURLScheme}
		}
		if p := models.Text(item.URLPattern); p != "" && !signpost.ValidItemPattern(p) {
			details[fmt.Sprintf("data.%d.urlPattern", i)] = []string{errURLPattern}
		}
	}
	if len(details) > 0 {
		return &cabana.ValidationError{Details: details}
	}
	return nil
}

var (
	_ pact.AdminController          = definitionsAdminController{}
	_ pact.AdminPermissioned        = definitionsAdminController{}
	_ pact.AdminRecordSource        = definitionsAdminController{}
	_ pact.AdminSingleton           = definitionsAdminController{}
	_ pact.DropdownOptionsProvider  = definitionsAdminController{}
	_ pact.DependentOptionsProvider = definitionsAdminController{}
	_ pact.FormBeforeCreate         = definitionsAdminController{}
	_ pact.FormBeforeUpdate         = definitionsAdminController{}
)