// Copyright 2016-present 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 hugolib

import (
	"errors"
	"fmt"
	"html/template"
	"os"
	"path"
	"strings"
	"sync"
	"time"

	"github.com/spf13/hugo/helpers"

	"github.com/spf13/viper"

	"github.com/bep/inflect"
	"github.com/fsnotify/fsnotify"
	"github.com/spf13/hugo/source"
	"github.com/spf13/hugo/tpl"
	jww "github.com/spf13/jwalterweatherman"
)

// Temporary feature flag to ease the refactoring of node vs page, see
// https://github.com/spf13/hugo/issues/2297
// TODO(bep) eventually remove
var nodePageFeatureFlag bool = true

// HugoSites represents the sites to build. Each site represents a language.
type HugoSites struct {
	Sites []*Site

	tmpl    tpl.Template
	runMode runmode

	multilingual *Multilingual
}

// NewHugoSites creates a new collection of sites given the input sites, building
// a language configuration based on those.
func newHugoSites(sites ...*Site) (*HugoSites, error) {
	langConfig, err := newMultiLingualFromSites(sites...)

	if err != nil {
		return nil, err
	}

	h := &HugoSites{multilingual: langConfig, Sites: sites}

	for _, s := range sites {
		s.owner = h
	}
	return h, nil
}

// NewHugoSitesFromConfiguration creates HugoSites from the global Viper config.
func NewHugoSitesFromConfiguration() (*HugoSites, error) {
	sites, err := createSitesFromConfig()
	if err != nil {
		return nil, err
	}
	return newHugoSites(sites...)
}

func createSitesFromConfig() ([]*Site, error) {
	var sites []*Site
	multilingual := viper.GetStringMap("languages")
	if len(multilingual) == 0 {
		sites = append(sites, newSite(helpers.NewDefaultLanguage()))
	}

	if len(multilingual) > 0 {
		var err error

		languages, err := toSortedLanguages(multilingual)

		if err != nil {
			return nil, fmt.Errorf("Failed to parse multilingual config: %s", err)
		}

		for _, lang := range languages {
			sites = append(sites, newSite(lang))
		}

	}

	return sites, nil
}

// Reset resets the sites and template caches, making it ready for a full rebuild.
func (h *HugoSites) reset() {
	for i, s := range h.Sites {
		h.Sites[i] = s.reset()
	}

	tpl.ResetCaches()
}

func (h *HugoSites) reCreateFromConfig() error {

	sites, err := createSitesFromConfig()

	if err != nil {
		return err
	}

	langConfig, err := newMultiLingualFromSites(sites...)

	if err != nil {
		return err
	}

	h.Sites = sites

	for _, s := range sites {
		s.owner = h
	}

	h.multilingual = langConfig

	return nil
}

func (h *HugoSites) toSiteInfos() []*SiteInfo {
	infos := make([]*SiteInfo, len(h.Sites))
	for i, s := range h.Sites {
		infos[i] = &s.Info
	}
	return infos
}

// BuildCfg holds build options used to, as an example, skip the render step.
type BuildCfg struct {
	// Whether we are in watch (server) mode
	Watching bool
	// Print build stats at the end of a build
	PrintStats bool
	// Reset site state before build. Use to force full rebuilds.
	ResetState bool
	// Re-creates the sites from configuration before a build.
	// This is needed if new languages are added.
	CreateSitesFromConfig bool
	// Skip rendering. Useful for testing.
	SkipRender bool
	// Use this to add templates to use for rendering.
	// Useful for testing.
	withTemplate func(templ tpl.Template) error
}

// Build builds all sites.
func (h *HugoSites) Build(config BuildCfg) error {

	t0 := time.Now()

	// TODO(bep) np init page collections
	for _, s := range h.Sites {
		if s.PageCollections == nil {
			s.PageCollections = newPageCollections()
		}
	}

	if config.ResetState {
		h.reset()
	}

	if config.CreateSitesFromConfig {
		if err := h.reCreateFromConfig(); err != nil {
			return err
		}
	}

	h.runMode.Watching = config.Watching

	// We should probably refactor the Site and pull up most of the logic from there to here,
	// but that seems like a daunting task.
	// So for now, if there are more than one site (language),
	// we pre-process the first one, then configure all the sites based on that.
	firstSite := h.Sites[0]

	if err := firstSite.preProcess(config); err != nil {
		return err
	}

	h.setupTranslationsForRegularPages()

	if len(h.Sites) > 1 {
		// Initialize the rest
		for _, site := range h.Sites[1:] {
			site.initializeSiteInfo()
		}
	}

	// TODO(bep) make a more logical grouping of these.
	h.assembleGitInfo()

	for _, s := range h.Sites {
		if err := s.postProcess(); err != nil {
			return err
		}
	}

	// TODO(bep) np createMissingNodes needs taxonomies and sections
	if err := h.createMissingNodes(); err != nil {
		return err
	}

	for _, s := range h.Sites {
		// TODO(bep) np Needed by all who use .Pages, .AllPages, .indexPages
		s.refreshPageCaches()
		s.setupPrevNext()
	}

	if err := h.assignMissingTranslations(); err != nil {
		return err
	}

	if err := h.preRender(config, whatChanged{source: true, other: true}); err != nil {
		return err
	}

	if !config.SkipRender {
		for _, s := range h.Sites {

			if err := s.render(); err != nil {
				return err
			}

			if config.PrintStats {
				s.Stats()
			}
		}

		if err := h.render(); err != nil {
			return err
		}
	}

	if config.PrintStats {
		jww.FEEDBACK.Printf("total in %v ms\n", int(1000*time.Since(t0).Seconds()))
	}

	return nil

}

// Rebuild rebuilds all sites.
func (h *HugoSites) Rebuild(config BuildCfg, events ...fsnotify.Event) error {
	t0 := time.Now()

	if config.CreateSitesFromConfig {
		return errors.New("Rebuild does not support 'CreateSitesFromConfig'. Use Build.")
	}

	if config.ResetState {
		return errors.New("Rebuild does not support 'ResetState'. Use Build.")
	}

	if !config.Watching {
		return errors.New("Rebuild called when not in watch mode")
	}

	h.runMode.Watching = config.Watching

	firstSite := h.Sites[0]

	for _, s := range h.Sites {
		s.resetBuildState()
	}

	helpers.InitLoggers()

	changed, err := firstSite.reBuild(events)

	if err != nil {
		return err
	}

	// Assign pages to sites per translation.
	h.setupTranslationsForRegularPages()

	if changed.source {
		h.assembleGitInfo()
		for _, s := range h.Sites {
			if err := s.postProcess(); err != nil {
				return err
			}
		}

		if err := h.createMissingNodes(); err != nil {
			return err
		}

		if err := h.assignMissingTranslations(); err != nil {
			return err
		}
	}

	if err := h.preRender(config, changed); err != nil {
		return err
	}

	if !config.SkipRender {
		for _, s := range h.Sites {
			if err := s.render(); err != nil {
				return err
			}
			if config.PrintStats {
				s.Stats()
			}
		}

		if err := h.render(); err != nil {
			return err
		}
	}

	if config.PrintStats {
		jww.FEEDBACK.Printf("total in %v ms\n", int(1000*time.Since(t0).Seconds()))
	}

	return nil

}

// Analyze prints a build report to Stdout.
// Useful for debugging.
func (h *HugoSites) Analyze() error {
	if err := h.Build(BuildCfg{SkipRender: true}); err != nil {
		return err
	}
	s := h.Sites[0]
	return s.ShowPlan(os.Stdout)
}

// Render the cross-site artifacts.
func (h *HugoSites) render() error {

	if !h.multilingual.enabled() {
		return nil
	}

	if viper.GetBool("disableSitemap") {
		return nil
	}

	// TODO(bep) DRY
	sitemapDefault := parseSitemap(viper.GetStringMap("sitemap"))

	s := h.Sites[0]

	smLayouts := []string{"sitemapindex.xml", "_default/sitemapindex.xml", "_internal/_default/sitemapindex.xml"}

	if err := s.renderAndWriteXML("sitemapindex", sitemapDefault.Filename,
		h.toSiteInfos(), s.appendThemeTemplates(smLayouts)...); err != nil {
		return err
	}

	return nil
}

func (h *HugoSites) assignMissingTranslations() error {
	// This looks heavy, but it should be a small number of nodes by now.
	allNodes := h.findAllPagesByNodeTypeNotIn(NodePage)
	for _, nodeType := range []NodeType{NodeHome, NodeSection, NodeTaxonomy, NodeTaxonomyTerms} {
		nodes := h.findPagesByNodeTypeIn(nodeType, allNodes)

		// Assign translations
		for _, t1 := range nodes {
			for _, t2 := range nodes {
				if t2.isTranslation(t1) {
					t1.translations = append(t1.translations, t2)
				}
			}
		}
	}
	return nil

}

// createMissingNodes creates home page, taxonomies etc. that isnt't created as an
// effect of having a content file.
func (h *HugoSites) createMissingNodes() error {
	// TODO(bep) np revisit this on languages -- as this is currently run after the page language distribution (due to taxonomies)
	// TODO(bep) np re above, Pages vs.
	// TODO(bep) np check node title etc.

	var newNodes Pages

	for _, s := range h.Sites {

		// home pages
		home := s.findPagesByNodeType(NodeHome)
		if len(home) > 1 {
			panic("Too many homes")
		}
		if len(home) == 0 {
			n := s.newHomePage()
			s.Nodes = append(s.Nodes, n)
			newNodes = append(newNodes, n)
		}

		// taxonomy list and terms pages
		taxonomies := s.Language.GetStringMapString("taxonomies")
		if len(taxonomies) > 0 {
			taxonomyPages := s.findPagesByNodeType(NodeTaxonomy)
			taxonomyTermsPages := s.findPagesByNodeType(NodeTaxonomyTerms)
			for _, plural := range taxonomies {
				tax := s.Taxonomies[plural]
				foundTaxonomyPage := false
				foundTaxonomyTermsPage := false
				for key, _ := range tax {
					for _, p := range taxonomyPages {
						if p.sections[0] == plural && p.sections[1] == key {
							foundTaxonomyPage = true
							break
						}
					}
					for _, p := range taxonomyTermsPages {
						if p.sections[0] == plural {
							foundTaxonomyTermsPage = true
							break
						}
					}
					if !foundTaxonomyPage {
						n := s.newTaxonomyPage(plural, key)
						s.Nodes = append(s.Nodes, n)
						newNodes = append(newNodes, n)
					}

					if !foundTaxonomyTermsPage {
						foundTaxonomyTermsPage = true
						n := s.newTaxonomyTermsPage(plural)
						s.Nodes = append(s.Nodes, n)
						newNodes = append(newNodes, n)
					}
				}
			}
		}

		sectionPages := s.findPagesByNodeType(NodeSection)
		if len(sectionPages) < len(s.Sections) {
			for name, section := range s.Sections {
				foundSection := false
				for _, sectionPage := range sectionPages {
					if sectionPage.sections[0] == name {
						foundSection = true
						break
					}
				}
				if !foundSection {
					n := s.newSectionPage(name, section)
					s.Nodes = append(s.Nodes, n)
					newNodes = append(newNodes, n)
				}
			}
		}
	}

	if len(newNodes) > 0 {
		first := h.Sites[0]
		first.AllNodes = append(first.AllNodes, newNodes...)
		for i := 1; i < len(h.Sites); i++ {
			h.Sites[i].AllNodes = first.AllNodes
		}
	}
	return nil
}

// Move the new* methods after cleanup in site.go
func (s *Site) newNodePage(typ NodeType) *Page {
	return &Page{
		Node: Node{
			Date:     s.Info.LastChange,
			Lastmod:  s.Info.LastChange,
			NodeType: typ,
			Data:     make(map[string]interface{}),
			Site:     &s.Info,
			language: s.Language,
		}, site: s}
}

func (s *Site) newHomePage() *Page {
	p := s.newNodePage(NodeHome)
	p.Title = s.Info.Title
	p.Data["Pages"] = Pages{}
	s.setPageURLs(p, "/")
	// TODO(bep) np check Data pages
	// TODO(bep) np check setURLs
	return p
}

func (s *Site) setPageURLs(p *Page, in string) {
	p.URLPath.URL = s.Info.pathSpec.URLizeAndPrep(in)
	p.URLPath.Permalink = s.Info.permalink(p.URLPath.URL)
	p.RSSLink = template.HTML(s.Info.permalink(in + ".xml"))
}

func (s *Site) newTaxonomyPage(plural, key string) *Page {

	p := s.newNodePage(NodeTaxonomy)

	p.sections = []string{plural, key}

	if s.Info.preserveTaxonomyNames {
		key = s.Info.pathSpec.MakePathSanitized(key)
	}

	if s.Info.preserveTaxonomyNames {
		// keep as is in the title
		p.Title = key
	} else {
		p.Title = strings.Replace(strings.Title(key), "-", " ", -1)
	}

	s.setPageURLs(p, path.Join(plural, key))

	return p
}

func (s *Site) newSectionPage(name string, section WeightedPages) *Page {

	p := s.newNodePage(NodeSection)
	p.sections = []string{name}

	sectionName := name
	if !s.Info.preserveTaxonomyNames && len(section) > 0 {
		sectionName = section[0].Page.Section()
	}

	sectionName = helpers.FirstUpper(sectionName)
	if viper.GetBool("pluralizeListTitles") {
		p.Title = inflect.Pluralize(sectionName)
	} else {
		p.Title = sectionName
	}
	s.setPageURLs(p, name)
	return p
}

func (s *Site) newTaxonomyTermsPage(plural string) *Page {
	p := s.newNodePage(NodeTaxonomyTerms)
	p.sections = []string{plural}
	p.Title = strings.Title(plural)
	return p
}

func (h *HugoSites) setupTranslationsForRegularPages() {

	master := h.Sites[0]

	regularPages := master.rawAllPages // master.findRawAllPagesByNodeType(NodePage)

	for _, p := range regularPages {
		if p.Lang() == "" {
			panic("Page language missing: " + p.Title)
		}

		shouldBuild := p.shouldBuild()

		for i, site := range h.Sites {
			if strings.HasPrefix(site.Language.Lang, p.Lang()) {
				site.updateBuildStats(p)
				if shouldBuild {
					site.Nodes = append(site.Nodes, p)
					p.Site = &site.Info
				}
			}

			if !shouldBuild {
				continue
			}

			if i == 0 {
				site.AllNodes = append(site.AllNodes, p)
			}
		}

	}

	// Pull over the collections from the master site
	for i := 1; i < len(h.Sites); i++ {
		h.Sites[i].AllNodes = h.Sites[0].AllNodes
		h.Sites[i].Data = h.Sites[0].Data
	}

	if len(h.Sites) > 1 {
		pages := h.Sites[0].AllNodes
		allTranslations := pagesToTranslationsMap(h.multilingual, pages)
		assignTranslationsToPages(allTranslations, pages)
	}
}

// preRender performs build tasks that need to be done as late as possible.
// Shortcode handling is the main task in here.
// TODO(bep) We need to look at the whole handler-chain construct with he below in mind.
// TODO(bep) np clean
func (h *HugoSites) preRender(cfg BuildCfg, changed whatChanged) error {

	for _, s := range h.Sites {
		if err := s.setCurrentLanguageConfig(); err != nil {
			return err
		}
		s.preparePagesForRender(cfg, changed)
	}

	return nil
}

func (s *Site) preparePagesForRender(cfg BuildCfg, changed whatChanged) {
	pageChan := make(chan *Page)
	wg := &sync.WaitGroup{}

	for i := 0; i < getGoMaxProcs()*4; i++ {
		wg.Add(1)
		go func(pages <-chan *Page, wg *sync.WaitGroup) {
			defer wg.Done()
			for p := range pages {

				if !changed.other && p.rendered {
					// No need to process it again.
					continue
				}

				// If we got this far it means that this is either a new Page pointer
				// or a template or similar has changed so wee need to do a rerendering
				// of the shortcodes etc.

				// Mark it as rendered
				p.rendered = true

				// If in watch mode, we need to keep the original so we can
				// repeat this process on rebuild.
				var rawContentCopy []byte
				if cfg.Watching {
					rawContentCopy = make([]byte, len(p.rawContent))
					copy(rawContentCopy, p.rawContent)
				} else {
					// Just reuse the same slice.
					rawContentCopy = p.rawContent
				}

				if p.Markup == "markdown" {
					tmpContent, tmpTableOfContents := helpers.ExtractTOC(rawContentCopy)
					p.TableOfContents = helpers.BytesToHTML(tmpTableOfContents)
					rawContentCopy = tmpContent
				}

				var err error
				if rawContentCopy, err = handleShortcodes(p, s.owner.tmpl, rawContentCopy); err != nil {
					jww.ERROR.Printf("Failed to handle shortcodes for page %s: %s", p.BaseFileName(), err)
				}

				if p.Markup != "html" {

					// Now we know enough to create a summary of the page and count some words
					summaryContent, err := p.setUserDefinedSummaryIfProvided(rawContentCopy)

					if err != nil {
						jww.ERROR.Printf("Failed to set user defined summary for page %q: %s", p.Path(), err)
					} else if summaryContent != nil {
						rawContentCopy = summaryContent.content
					}

					p.Content = helpers.BytesToHTML(rawContentCopy)

					if summaryContent == nil {
						p.setAutoSummary()
					}

				} else {
					p.Content = helpers.BytesToHTML(rawContentCopy)
				}

				// no need for this anymore
				rawContentCopy = nil

				//analyze for raw stats
				p.analyzePage()

			}
		}(pageChan, wg)
	}

	for _, p := range s.Nodes {
		pageChan <- p
	}

	close(pageChan)

	wg.Wait()

}

// Pages returns all pages for all sites.
func (h *HugoSites) Pages() Pages {
	return h.Sites[0].AllPages
}

func handleShortcodes(p *Page, t tpl.Template, rawContentCopy []byte) ([]byte, error) {
	if len(p.contentShortCodes) > 0 {
		jww.DEBUG.Printf("Replace %d shortcodes in %q", len(p.contentShortCodes), p.BaseFileName())
		shortcodes, err := executeShortcodeFuncMap(p.contentShortCodes)

		if err != nil {
			return rawContentCopy, err
		}

		rawContentCopy, err = replaceShortcodeTokens(rawContentCopy, shortcodePlaceholderPrefix, shortcodes)

		if err != nil {
			jww.FATAL.Printf("Failed to replace short code tokens in %s:\n%s", p.BaseFileName(), err.Error())
		}
	}

	return rawContentCopy, nil
}

func (s *Site) updateBuildStats(page *Page) {
	if page.IsDraft() {
		s.draftCount++
	}

	if page.IsFuture() {
		s.futureCount++
	}

	if page.IsExpired() {
		s.expiredCount++
	}
}

// TODO(bep) np remove
func (h *HugoSites) findAllPagesByNodeType(n NodeType) Pages {
	return h.Sites[0].findAllPagesByNodeType(n)
}

func (h *HugoSites) findPagesByNodeTypeNotIn(n NodeType, inPages Pages) Pages {
	return h.Sites[0].findPagesByNodeTypeNotIn(n, inPages)
}

func (h *HugoSites) findPagesByNodeTypeIn(n NodeType, inPages Pages) Pages {
	return h.Sites[0].findPagesByNodeTypeIn(n, inPages)
}

func (h *HugoSites) findAllPagesByNodeTypeNotIn(n NodeType) Pages {
	return h.findPagesByNodeTypeNotIn(n, h.Sites[0].AllNodes)
}

// Convenience func used in tests to build a single site/language excluding render phase.
func buildSiteSkipRender(s *Site, additionalTemplates ...string) error {
	return doBuildSite(s, false, additionalTemplates...)
}

// Convenience func used in tests to build a single site/language including render phase.
func buildAndRenderSite(s *Site, additionalTemplates ...string) error {
	return doBuildSite(s, true, additionalTemplates...)
}

// Convenience func used in tests to build a single site/language.
func doBuildSite(s *Site, render bool, additionalTemplates ...string) error {
	if s.PageCollections == nil {
		s.PageCollections = newPageCollections()
	}
	sites, err := newHugoSites(s)
	if err != nil {
		return err
	}

	addTemplates := func(templ tpl.Template) error {
		for i := 0; i < len(additionalTemplates); i += 2 {
			err := templ.AddTemplate(additionalTemplates[i], additionalTemplates[i+1])
			if err != nil {
				return err
			}
		}
		return nil
	}

	config := BuildCfg{SkipRender: !render, withTemplate: addTemplates}
	return sites.Build(config)
}

// Convenience func used in tests.
func newHugoSitesFromSourceAndLanguages(input []source.ByteSource, languages helpers.Languages) (*HugoSites, error) {
	if len(languages) == 0 {
		panic("Must provide at least one language")
	}
	first := &Site{
		Source:   &source.InMemorySource{ByteSource: input},
		Language: languages[0],
	}
	if len(languages) == 1 {
		return newHugoSites(first)
	}

	sites := make([]*Site, len(languages))
	sites[0] = first
	for i := 1; i < len(languages); i++ {
		sites[i] = &Site{Language: languages[i]}
	}

	return newHugoSites(sites...)

}

// Convenience func used in tests.
func newHugoSitesDefaultLanguage() (*HugoSites, error) {
	return newHugoSitesFromSourceAndLanguages(nil, helpers.Languages{helpers.NewDefaultLanguage()})
}