Create a struct with all of Hugo's config options

Primary motivation is documentation, but it will also hopefully simplify the code.

Also,

* Lower case the default output format names; this is in line with the custom ones (map keys) and how
it's treated all the places. This avoids doing `stringds.EqualFold` everywhere.

Closes #10896
Closes #10620

18 files changed, 2454 insertions, 298 deletions

diff --git a/config/allconfig/allconfig.go b/config/allconfig/allconfig.go
new file mode 100644
index 000000000..4daae3ccb
--- /dev/null
+++ b/config/allconfig/allconfig.go
@@ -0,0 +1,813 @@
+// Copyright 2023 The Hugo Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package allconfig contains the full configuration for Hugo.
+// <docsmeta>{ "name": "Configuration", "description": "This section holds all configiration options in Hugo." }</docsmeta>
+package allconfig
+
+import (
+	"errors"
+	"fmt"
+	"reflect"
+	"regexp"
+	"sort"
+	"strconv"
+	"strings"
+	"time"
+
+	"github.com/gohugoio/hugo/cache/filecache"
+	"github.com/gohugoio/hugo/common/maps"
+	"github.com/gohugoio/hugo/common/urls"
+	"github.com/gohugoio/hugo/config"
+	"github.com/gohugoio/hugo/config/privacy"
+	"github.com/gohugoio/hugo/config/security"
+	"github.com/gohugoio/hugo/config/services"
+	"github.com/gohugoio/hugo/deploy"
+	"github.com/gohugoio/hugo/helpers"
+	"github.com/gohugoio/hugo/langs"
+	"github.com/gohugoio/hugo/markup/markup_config"
+	"github.com/gohugoio/hugo/media"
+	"github.com/gohugoio/hugo/minifiers"
+	"github.com/gohugoio/hugo/modules"
+	"github.com/gohugoio/hugo/navigation"
+	"github.com/gohugoio/hugo/output"
+	"github.com/gohugoio/hugo/related"
+	"github.com/gohugoio/hugo/resources/images"
+	"github.com/gohugoio/hugo/resources/page"
+	"github.com/gohugoio/hugo/resources/page/pagemeta"
+	"github.com/spf13/afero"
+
+	xmaps "golang.org/x/exp/maps"
+)
+
+// InternalConfig is the internal configuration for Hugo, not read from any user provided config file.
+type InternalConfig struct {
+	// Server mode?
+	Running bool
+
+	Quiet             bool
+	Verbose           bool
+	Clock             string
+	Watch             bool
+	DisableLiveReload bool
+	LiveReloadPort    int
+}
+
+type Config struct {
+	// For internal use only.
+	Internal InternalConfig `mapstructure:"-" json:"-"`
+	// For internal use only.
+	C ConfigCompiled `mapstructure:"-" json:"-"`
+
+	RootConfig
+
+	// Author information.
+	Author map[string]any
+
+	// Social links.
+	Social map[string]string
+
+	// The build configuration section contains build-related configuration options.
+	// <docsmeta>{"identifiers": ["build"] }</docsmeta>
+	Build config.BuildConfig `mapstructure:"-"`
+
+	// The caches configuration section contains cache-related configuration options.
+	// <docsmeta>{"identifiers": ["caches"] }</docsmeta>
+	Caches filecache.Configs `mapstructure:"-"`
+
+	// The markup configuration section contains markup-related configuration options.
+	// <docsmeta>{"identifiers": ["markup"] }</docsmeta>
+	Markup markup_config.Config `mapstructure:"-"`
+
+	// The mediatypes configuration section maps the MIME type (a string) to a configuration object for that type.
+	// <docsmeta>{"identifiers": ["mediatypes"], "refs": ["types:media:type"] }</docsmeta>
+	MediaTypes *config.ConfigNamespace[map[string]media.MediaTypeConfig, media.Types] `mapstructure:"-"`
+
+	Imaging *config.ConfigNamespace[images.ImagingConfig, images.ImagingConfigInternal] `mapstructure:"-"`
+
+	// The outputformats configuration sections maps a format name (a string) to a configuration object for that format.
+	OutputFormats *config.ConfigNamespace[map[string]output.OutputFormatConfig, output.Formats] `mapstructure:"-"`
+
+	// The outputs configuration section maps a Page Kind (a string) to a slice of output formats.
+	// This can be overridden in the front matter.
+	Outputs map[string][]string `mapstructure:"-"`
+
+	// The cascade configuration section contains the top level front matter cascade configuration options,
+	// a slice of page matcher and params to apply to those pages.
+	Cascade *config.ConfigNamespace[[]page.PageMatcherParamsConfig, map[page.PageMatcher]maps.Params] `mapstructure:"-"`
+
+	// Menu configuration.
+	// <docsmeta>{"refs": ["config:languages:menus"] }</docsmeta>
+	Menus *config.ConfigNamespace[map[string]navigation.MenuConfig, navigation.Menus] `mapstructure:"-"`
+
+	// The deployment configuration section contains for hugo deploy.
+	Deployment deploy.DeployConfig `mapstructure:"-"`
+
+	// Module configuration.
+	Module modules.Config `mapstructure:"-"`
+
+	// Front matter configuration.
+	Frontmatter pagemeta.FrontmatterConfig `mapstructure:"-"`
+
+	// Minification configuration.
+	Minify minifiers.MinifyConfig `mapstructure:"-"`
+
+	// Permalink configuration.
+	Permalinks map[string]string `mapstructure:"-"`
+
+	// Taxonomy configuration.
+	Taxonomies map[string]string `mapstructure:"-"`
+
+	// Sitemap configuration.
+	Sitemap config.SitemapConfig `mapstructure:"-"`
+
+	// Related content configuration.
+	Related related.Config `mapstructure:"-"`
+
+	// Server configuration.
+	Server config.Server `mapstructure:"-"`
+
+	// Privacy configuration.
+	Privacy privacy.Config `mapstructure:"-"`
+
+	// Security configuration.
+	Security security.Config `mapstructure:"-"`
+
+	// Services configuration.
+	Services services.Config `mapstructure:"-"`
+
+	// User provided parameters.
+	// <docsmeta>{"refs": ["config:languages:params"] }</docsmeta>
+	Params maps.Params `mapstructure:"-"`
+
+	// The languages configuration sections maps a language code (a string) to a configuration object for that language.
+	Languages map[string]langs.LanguageConfig `mapstructure:"-"`
+
+	// UglyURLs configuration. Either a boolean or a sections map.
+	UglyURLs any `mapstructure:"-"`
+}
+
+type configCompiler interface {
+	CompileConfig() error
+}
+
+func (c Config) cloneForLang() *Config {
+	x := c
+	// Collapse all static dirs to one.
+	x.StaticDir = x.staticDirs()
+	// These will go away soon ...
+	x.StaticDir0 = nil
+	x.StaticDir1 = nil
+	x.StaticDir2 = nil
+	x.StaticDir3 = nil
+	x.StaticDir4 = nil
+	x.StaticDir5 = nil
+	x.StaticDir6 = nil
+	x.StaticDir7 = nil
+	x.StaticDir8 = nil
+	x.StaticDir9 = nil
+	x.StaticDir10 = nil
+
+	return &x
+}
+
+func (c *Config) CompileConfig() error {
+	s := c.Timeout
+	if _, err := strconv.Atoi(s); err == nil {
+		// A number, assume seconds.
+		s = s + "s"
+	}
+	timeout, err := time.ParseDuration(s)
+	if err != nil {
+		return fmt.Errorf("failed to parse timeout: %s", err)
+	}
+	disabledKinds := make(map[string]bool)
+	for _, kind := range c.DisableKinds {
+		disabledKinds[strings.ToLower(kind)] = true
+	}
+	kindOutputFormats := make(map[string]output.Formats)
+	isRssDisabled := disabledKinds["rss"]
+	outputFormats := c.OutputFormats.Config
+	for kind, formats := range c.Outputs {
+		if disabledKinds[kind] {
+			continue
+		}
+		for _, format := range formats {
+			if isRssDisabled && format == "rss" {
+				// Legacy config.
+				continue
+			}
+			f, found := outputFormats.GetByName(format)
+			if !found {
+				return fmt.Errorf("unknown output format %q for kind %q", format, kind)
+			}
+			kindOutputFormats[kind] = append(kindOutputFormats[kind], f)
+		}
+	}
+
+	disabledLangs := make(map[string]bool)
+	for _, lang := range c.DisableLanguages {
+		if lang == c.DefaultContentLanguage {
+			return fmt.Errorf("cannot disable default content language %q", lang)
+		}
+		disabledLangs[lang] = true
+	}
+
+	ignoredErrors := make(map[string]bool)
+	for _, err := range c.IgnoreErrors {
+		ignoredErrors[strings.ToLower(err)] = true
+	}
+
+	baseURL, err := urls.NewBaseURLFromString(c.BaseURL)
+	if err != nil {
+		return err
+	}
+
+	isUglyURL := func(section string) bool {
+		switch v := c.UglyURLs.(type) {
+		case bool:
+			return v
+		case map[string]bool:
+			return v[section]
+		default:
+			return false
+		}
+	}
+
+	ignoreFile := func(s string) bool {
+		return false
+	}
+	if len(c.IgnoreFiles) > 0 {
+		regexps := make([]*regexp.Regexp, len(c.IgnoreFiles))
+		for i, pattern := range c.IgnoreFiles {
+			var err error
+			regexps[i], err = regexp.Compile(pattern)
+			if err != nil {
+				return fmt.Errorf("failed to compile ignoreFiles pattern %q: %s", pattern, err)
+			}
+		}
+		ignoreFile = func(s string) bool {
+			for _, r := range regexps {
+				if r.MatchString(s) {
+					return true
+				}
+			}
+			return false
+		}
+	}
+
+	var clock time.Time
+	if c.Internal.Clock != "" {
+		var err error
+		clock, err = time.Parse(time.RFC3339, c.Internal.Clock)
+		if err != nil {
+			return fmt.Errorf("failed to parse clock: %s", err)
+		}
+	}
+
+	c.C = ConfigCompiled{
+		Timeout:           timeout,
+		BaseURL:           baseURL,
+		BaseURLLiveReload: baseURL,
+		DisabledKinds:     disabledKinds,
+		DisabledLanguages: disabledLangs,
+		IgnoredErrors:     ignoredErrors,
+		KindOutputFormats: kindOutputFormats,
+		CreateTitle:       helpers.GetTitleFunc(c.TitleCaseStyle),
+		IsUglyURLSection:  isUglyURL,
+		IgnoreFile:        ignoreFile,
+		MainSections:      c.MainSections,
+		Clock:             clock,
+	}
+
+	for _, s := range allDecoderSetups {
+		if getCompiler := s.getCompiler; getCompiler != nil {
+			if err := getCompiler(c).CompileConfig(); err != nil {
+				return err
+			}
+		}
+	}
+
+	return nil
+}
+
+func (c Config) IsKindEnabled(kind string) bool {
+	return !c.C.DisabledKinds[kind]
+}
+
+func (c Config) IsLangDisabled(lang string) bool {
+	return c.C.DisabledLanguages[lang]
+}
+
+// ConfigCompiled holds values and functions that are derived from the config.
+type ConfigCompiled struct {
+	Timeout           time.Duration
+	BaseURL           urls.BaseURL
+	BaseURLLiveReload urls.BaseURL
+	KindOutputFormats map[string]output.Formats
+	DisabledKinds     map[string]bool
+	DisabledLanguages map[string]bool
+	IgnoredErrors     map[string]bool
+	CreateTitle       func(s string) string
+	IsUglyURLSection  func(section string) bool
+	IgnoreFile        func(filename string) bool
+	MainSections      []string
+	Clock             time.Time
+}
+
+// This may be set after the config is compiled.
+func (c *ConfigCompiled) SetMainSections(sections []string) {
+	c.MainSections = sections
+}
+
+// This is set after the config is compiled by the server command.
+func (c *ConfigCompiled) SetBaseURL(baseURL, baseURLLiveReload urls.BaseURL) {
+	c.BaseURL = baseURL
+	c.BaseURLLiveReload = baseURLLiveReload
+}
+
+// RootConfig holds all the top-level configuration options in Hugo
+type RootConfig struct {
+
+	// The base URL of the site.
+	// Note that the default value is empty, but Hugo requires a valid URL (e.g. "https://example.com/") to work properly.
+	// <docsmeta>{"identifiers": ["URL"] }</docsmeta>
+	BaseURL string
+
+	// Whether to build content marked as draft.X
+	// <docsmeta>{"identifiers": ["draft"] }</docsmeta>
+	BuildDrafts bool
+
+	// Whether to build content with expiryDate in the past.
+	// <docsmeta>{"identifiers": ["expiryDate"] }</docsmeta>
+	BuildExpired bool
+
+	// Whether to build content with publishDate in the future.
+	// <docsmeta>{"identifiers": ["publishDate"] }</docsmeta>
+	BuildFuture bool
+
+	// Copyright information.
+	Copyright string
+
+	// The language to apply to content without any Clolanguage indicator.
+	DefaultContentLanguage string
+
+	// By defefault, we put the default content language in the root and the others below their language ID, e.g. /no/.
+	// Set this to true to put all languages below their language ID.
+	DefaultContentLanguageInSubdir bool
+
+	// Disable creation of alias redirect pages.
+	DisableAliases bool
+
+	// Disable lower casing of path segments.
+	DisablePathToLower bool
+
+	// Disable page kinds from build.
+	DisableKinds []string
+
+	// A list of languages to disable.
+	DisableLanguages []string
+
+	// Disable the injection of the Hugo generator tag on the home page.
+	DisableHugoGeneratorInject bool
+
+	// Enable replacement in Pages' Content of Emoji shortcodes with their equivalent Unicode characters.
+	// <docsmeta>{"identifiers": ["Content", "Unicode"] }</docsmeta>
+	EnableEmoji bool
+
+	// THe main section(s) of the site.
+	// If not set, Hugo will try to guess this from the content.
+	MainSections []string
+
+	// Enable robots.txt generation.
+	EnableRobotsTXT bool
+
+	// When enabled, Hugo will apply Git version information to each Page if possible, which
+	// can be used to keep lastUpdated in synch and to print version information.
+	// <docsmeta>{"identifiers": ["Page"] }</docsmeta>
+	EnableGitInfo bool
+
+	// Enable to track, calculate and print metrics.
+	TemplateMetrics bool
+
+	// Enable to track, print and calculate metric hints.
+	TemplateMetricsHints bool
+
+	// Enable to disable the build lock file.
+	NoBuildLock bool
+
+	// A list of error IDs to ignore.
+	IgnoreErrors []string
+
+	// A list of regexps that match paths to ignore.
+	// Deprecated: Use the settings on module imports.
+	IgnoreFiles []string
+
+	// Ignore cache.
+	IgnoreCache bool
+
+	// Enable to print greppable placeholders (on the form "[i18n] TRANSLATIONID") for missing translation strings.
+	EnableMissingTranslationPlaceholders bool
+
+	// Enable to print warnings for missing translation strings.
+	LogI18nWarnings bool
+
+	// ENable to print warnings for multiple files published to the same destination.
+	LogPathWarnings bool
+
+	// The configured environment. Default is "development" for server and "production" for build.
+	Environment string
+
+	// The default language code.
+	LanguageCode string
+
+	// Enable if the site content has CJK language (Chinese, Japanese, or Korean). This affects how Hugo counts words.
+	HasCJKLanguage bool
+
+	// The default number of pages per page when paginating.
+	Paginate int
+
+	// The path to use when creating pagination URLs, e.g. "page" in /page/2/.
+	PaginatePath string
+
+	// Whether to pluralize default list titles.
+	// Note that this currently only works for English, but you can provide your own title in the content file's front matter.
+	PluralizeListTitles bool
+
+	// Make all relative URLs absolute using the baseURL.
+	// <docsmeta>{"identifiers": ["baseURL"] }</docsmeta>
+	CanonifyURLs bool
+
+	// Enable this to make all relative URLs relative to content root. Note that this does not affect absolute URLs.
+	RelativeURLs bool
+
+	// Removes non-spacing marks from composite characters in content paths.
+	RemovePathAccents bool
+
+	// Whether to track and print unused templates during the build.
+	PrintUnusedTemplates bool
+
+	// URL to be used as a placeholder when a page reference cannot be found in ref or relref. Is used as-is.
+	RefLinksNotFoundURL string
+
+	// When using ref or relref to resolve page links and a link cannot be resolved, it will be logged with this log level.
+	// Valid values are ERROR (default) or WARNING. Any ERROR will fail the build (exit -1).
+	RefLinksErrorLevel string
+
+	// This will create a menu with all the sections as menu items and all the sections’ pages as “shadow-members”.
+	SectionPagesMenu string
+
+	// The length of text in words to show in a .Summary.
+	SummaryLength int
+
+	// The site title.
+	Title string
+
+	// The theme(s) to use.
+	// See Modules for more a more flexible way to load themes.
+	Theme []string
+
+	// Timeout for generating page contents, specified as a duration or in milliseconds.
+	Timeout string
+
+	// The time zone (or location), e.g. Europe/Oslo, used to parse front matter dates without such information and in the time function.
+	TimeZone string
+
+	// Set titleCaseStyle to specify the title style used by the title template function and the automatic section titles in Hugo.
+	// It defaults to AP Stylebook for title casing, but you can also set it to Chicago or Go (every word starts with a capital letter).
+	TitleCaseStyle string
+
+	// The editor used for opening up new content.
+	NewContentEditor string
+
+	// Don't sync modification time of files for the static mounts.
+	NoTimes bool
+
+	// Don't sync modification time of files for the static mounts.
+	NoChmod bool
+
+	// Clean the destination folder before a new build.
+	// This currently only handles static files.
+	CleanDestinationDir bool
+
+	// A Glob pattern of module paths to ignore in the _vendor folder.
+	IgnoreVendorPaths string
+
+	config.CommonDirs `mapstructure:",squash"`
+
+	// The odd constructs below are kept for backwards compatibility.
+	// Deprecated: Use module mount config instead.
+	StaticDir []string
+	// Deprecated: Use module mount config instead.
+	StaticDir0 []string
+	// Deprecated: Use module mount config instead.
+	StaticDir1 []string
+	// Deprecated: Use module mount config instead.
+	StaticDir2 []string
+	// Deprecated: Use module mount config instead.
+	StaticDir3 []string
+	// Deprecated: Use module mount config instead.
+	StaticDir4 []string
+	// Deprecated: Use module mount config instead.
+	StaticDir5 []string
+	// Deprecated: Use module mount config instead.
+	StaticDir6 []string
+	// Deprecated: Use module mount config instead.
+	StaticDir7 []string
+	// Deprecated: Use module mount config instead.
+	StaticDir8 []string
+	// Deprecated: Use module mount config instead.
+	StaticDir9 []string
+	// Deprecated: Use module mount config instead.
+	StaticDir10 []string
+}
+
+func (c RootConfig) staticDirs() []string {
+	var dirs []string
+	dirs = append(dirs, c.StaticDir...)
+	dirs = append(dirs, c.StaticDir0...)
+	dirs = append(dirs, c.StaticDir1...)
+	dirs = append(dirs, c.StaticDir2...)
+	dirs = append(dirs, c.StaticDir3...)
+	dirs = append(dirs, c.StaticDir4...)
+	dirs = append(dirs, c.StaticDir5...)
+	dirs = append(dirs, c.StaticDir6...)
+	dirs = append(dirs, c.StaticDir7...)
+	dirs = append(dirs, c.StaticDir8...)
+	dirs = append(dirs, c.StaticDir9...)
+	dirs = append(dirs, c.StaticDir10...)
+	return helpers.UniqueStringsReuse(dirs)
+}
+
+type Configs struct {
+	Base                *Config
+	LoadingInfo         config.LoadConfigResult
+	LanguageConfigMap   map[string]*Config
+	LanguageConfigSlice []*Config
+
+	IsMultihost           bool
+	Languages             langs.Languages
+	LanguagesDefaultFirst langs.Languages
+
+	Modules       modules.Modules
+	ModulesClient *modules.Client
+
+	configLangs []config.AllProvider
+}
+
+func (c *Configs) IsZero() bool {
+	// A config always has at least one language.
+	return c == nil || len(c.Languages) == 0
+}
+
+func (c *Configs) Init() error {
+	c.configLangs = make([]config.AllProvider, len(c.Languages))
+	for i, l := range c.LanguagesDefaultFirst {
+		c.configLangs[i] = ConfigLanguage{
+			m:          c,
+			config:     c.LanguageConfigMap[l.Lang],
+			baseConfig: c.LoadingInfo.BaseConfig,
+			language:   l,
+		}
+	}
+
+	if len(c.Modules) == 0 {
+		return errors.New("no modules loaded (ned at least the main module)")
+	}
+
+	// Apply default project mounts.
+	if err := modules.ApplyProjectConfigDefaults(c.Modules[0], c.configLangs...); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func (c Configs) ConfigLangs() []config.AllProvider {
+	return c.configLangs
+}
+
+func (c Configs) GetFirstLanguageConfig() config.AllProvider {
+	return c.configLangs[0]
+}
+
+func (c Configs) GetByLang(lang string) config.AllProvider {
+	for _, l := range c.configLangs {
+		if l.Language().Lang == lang {
+			return l
+		}
+	}
+	return nil
+}
+
+// FromLoadConfigResult creates a new Config from res.
+func FromLoadConfigResult(fs afero.Fs, res config.LoadConfigResult) (*Configs, error) {
+	if !res.Cfg.IsSet("languages") {
+		// We need at least one
+		lang := res.Cfg.GetString("defaultContentLanguage")
+		res.Cfg.Set("languages", maps.Params{lang: maps.Params{}})
+	}
+	bcfg := res.BaseConfig
+	cfg := res.Cfg
+
+	all := &Config{}
+	err := decodeConfigFromParams(fs, bcfg, cfg, all, nil)
+	if err != nil {
+		return nil, err
+	}
+
+	langConfigMap := make(map[string]*Config)
+	var langConfigs []*Config
+
+	languagesConfig := cfg.GetStringMap("languages")
+	var isMultiHost bool
+
+	if err := all.CompileConfig(); err != nil {
+		return nil, err
+	}
+
+	for k, v := range languagesConfig {
+		mergedConfig := config.New()
+		var differentRootKeys []string
+		switch x := v.(type) {
+		case maps.Params:
+			for kk, vv := range x {
+				if kk == "baseurl" {
+					// baseURL configure don the language level is a multihost setup.
+					isMultiHost = true
+				}
+				mergedConfig.Set(kk, vv)
+				if cfg.IsSet(kk) {
+					rootv := cfg.Get(kk)
+					// This overrides a root key and potentially needs a merge.
+					if !reflect.DeepEqual(rootv, vv) {
+						switch vvv := vv.(type) {
+						case maps.Params:
+							differentRootKeys = append(differentRootKeys, kk)
+
+							// Use the language value as base.
+							mergedConfigEntry := xmaps.Clone(vvv)
+							// Merge in the root value.
+							maps.MergeParams(mergedConfigEntry, rootv.(maps.Params))
+
+							mergedConfig.Set(kk, mergedConfigEntry)
+						default:
+							// Apply new values to the root.
+							differentRootKeys = append(differentRootKeys, "")
+						}
+					}
+				} else {
+					// Apply new values to the root.
+					differentRootKeys = append(differentRootKeys, "")
+				}
+			}
+			differentRootKeys = helpers.UniqueStringsSorted(differentRootKeys)
+
+			if len(differentRootKeys) == 0 {
+				langConfigMap[k] = all
+				continue
+			}
+
+			// Create a copy of the complete config and replace the root keys with the language specific ones.
+			clone := all.cloneForLang()
+			if err := decodeConfigFromParams(fs, bcfg, mergedConfig, clone, differentRootKeys); err != nil {
+				return nil, fmt.Errorf("failed to decode config for language %q: %w", k, err)
+			}
+			if err := clone.CompileConfig(); err != nil {
+				return nil, err
+			}
+			langConfigMap[k] = clone
+		case maps.ParamsMergeStrategy:
+		default:
+			panic(fmt.Sprintf("unknown type in languages config: %T", v))
+
+		}
+	}
+
+	var languages langs.Languages
+	defaultContentLanguage := all.DefaultContentLanguage
+	for k, v := range langConfigMap {
+		languageConf := v.Languages[k]
+		language, err := langs.NewLanguage(k, defaultContentLanguage, v.TimeZone, languageConf)
+		if err != nil {
+			return nil, err
+		}
+		languages = append(languages, language)
+	}
+
+	// Sort the sites by language weight (if set) or lang.
+	sort.Slice(languages, func(i, j int) bool {
+		li := languages[i]
+		lj := languages[j]
+		if li.Weight != lj.Weight {
+			return li.Weight < lj.Weight
+		}
+		return li.Lang < lj.Lang
+	})
+
+	for _, l := range languages {
+		langConfigs = append(langConfigs, langConfigMap[l.Lang])
+	}
+
+	var languagesDefaultFirst langs.Languages
+	for _, l := range languages {
+		if l.Lang == defaultContentLanguage {
+			languagesDefaultFirst = append(languagesDefaultFirst, l)
+		}
+	}
+	for _, l := range languages {
+		if l.Lang != defaultContentLanguage {
+			languagesDefaultFirst = append(languagesDefaultFirst, l)
+		}
+	}
+
+	bcfg.PublishDir = all.PublishDir
+	res.BaseConfig = bcfg
+
+	cm := &Configs{
+		Base:                  all,
+		LanguageConfigMap:     langConfigMap,
+		LanguageConfigSlice:   langConfigs,
+		LoadingInfo:           res,
+		IsMultihost:           isMultiHost,
+		Languages:             languages,
+		LanguagesDefaultFirst: languagesDefaultFirst,
+	}
+
+	return cm, nil
+}
+
+func decodeConfigFromParams(fs afero.Fs, bcfg config.BaseConfig, p config.Provider, target *Config, keys []string) error {
+
+	var decoderSetups []decodeWeight
+
+	if len(keys) == 0 {
+		for _, v := range allDecoderSetups {
+			decoderSetups = append(decoderSetups, v)
+		}
+	} else {
+		for _, key := range keys {
+			if v, found := allDecoderSetups[key]; found {
+				decoderSetups = append(decoderSetups, v)
+			} else {
+				return fmt.Errorf("unknown config key %q", key)
+			}
+		}
+	}
+
+	// Sort them to get the dependency order right.
+	sort.Slice(decoderSetups, func(i, j int) bool {
+		ki, kj := decoderSetups[i], decoderSetups[j]
+		if ki.weight == kj.weight {
+			return ki.key < kj.key
+		}
+		return ki.weight < kj.weight
+	})
+
+	for _, v := range decoderSetups {
+		p := decodeConfig{p: p, c: target, fs: fs, bcfg: bcfg}
+		if err := v.decode(v, p); err != nil {
+			return fmt.Errorf("failed to decode %q: %w", v.key, err)
+		}
+	}
+
+	return nil
+}
+
+func createDefaultOutputFormats(allFormats output.Formats) map[string][]string {
+	if len(allFormats) == 0 {
+		panic("no output formats")
+	}
+	rssOut, rssFound := allFormats.GetByName(output.RSSFormat.Name)
+	htmlOut, _ := allFormats.GetByName(output.HTMLFormat.Name)
+
+	defaultListTypes := []string{htmlOut.Name}
+	if rssFound {
+		defaultListTypes = append(defaultListTypes, rssOut.Name)
+	}
+
+	m := map[string][]string{
+		page.KindPage:     {htmlOut.Name},
+		page.KindHome:     defaultListTypes,
+		page.KindSection:  defaultListTypes,
+		page.KindTerm: