// Copyright © 2013 Steve Francia <spf@spf13.com>.
//
// Licensed under the Simple Public 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://opensource.org/licenses/Simple-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 (
	"bitbucket.org/pkg/inflect"
	"bytes"
	"fmt"
	"github.com/spf13/hugo/source"
	"github.com/spf13/hugo/target"
	helpers "github.com/spf13/hugo/template"
	"github.com/spf13/hugo/template/bundle"
	"github.com/spf13/hugo/transform"
	"github.com/spf13/nitro"
	"html/template"
	"io"
	"net/url"
	"os"
	"strings"
	"time"
)

var DefaultTimer *nitro.B

func MakePermalink(base *url.URL, path *url.URL) *url.URL {
	return base.ResolveReference(path)
}

// Site contains all the information relevent for constructing a static
// site.  The basic flow of information is as follows:
//
// 1. A list of Files is parsed and then converted into Pages.
//
// 2. Pages contain sections (based on the file they were generated from),
//    aliases and slugs (included in a pages frontmatter) which are the
//		various targets that will get generated.  There will be canonical
//		listing.
//
// 3. Indexes are created via configuration and will present some aspect of
//    the final page and typically a perm url.
//
// 4. All Pages are passed through a template based on their desired
// 		layout based on numerous different elements.
//
// 5. The entire collection of files is written to disk.
type Site struct {
	Config      Config
	Pages       Pages
	Tmpl        bundle.Template
	Indexes     IndexList
	Source      source.Input
	Sections    Index
	Info        SiteInfo
	Shortcodes  map[string]ShortcodeFunc
	timer       *nitro.B
	Transformer *transform.Transformer
	Target      target.Output
	Alias       target.AliasPublisher
}

type SiteInfo struct {
	BaseUrl    template.URL
	Indexes    OrderedIndexList
	Recent     *Pages
	LastChange time.Time
	Title      string
	Config     *Config
}

func init() {
	DefaultTimer = nitro.Initalize()
}

func (s *Site) timerStep(step string) {
	if s.timer == nil {
		s.timer = DefaultTimer
	}
	s.timer.Step(step)
}

func (s *Site) Build() (err error) {
	if err = s.Process(); err != nil {
		return
	}
	if err = s.Render(); err != nil {
		fmt.Printf("Error rendering site: %s\nAvailable templates:\n", err)
		for _, template := range s.Tmpl.Templates() {
			fmt.Printf("\t%s\n", template.Name())
		}
		return
	}
	return nil
}

func (s *Site) Analyze() {
	s.Process()
	s.initTarget()
	s.Alias = &target.HTMLRedirectAlias{
		PublishDir: s.absPublishDir(),
	}
	s.ShowPlan(os.Stdout)
}

func (s *Site) prepTemplates() {
	s.Tmpl = bundle.NewTemplate()
	s.Tmpl.LoadTemplates(s.absLayoutDir())
}

func (s *Site) addTemplate(name, data string) error {
	return s.Tmpl.AddTemplate(name, data)
}

func (s *Site) Process() (err error) {
	s.initialize()
	s.prepTemplates()
	s.timerStep("initialize & template prep")
	if err = s.CreatePages(); err != nil {
		return err
	}
	s.setupPrevNext()
	s.timerStep("import pages")
	if err = s.BuildSiteMeta(); err != nil {
		return
	}
	s.timerStep("build indexes")
	return
}

func (s *Site) setupPrevNext() {
	for i, page := range s.Pages {
		if i < len(s.Pages)-1 {
			page.Next = s.Pages[i+1]
		}

		if i > 0 {
			page.Prev = s.Pages[i-1]
		}
	}
}

func (s *Site) Render() (err error) {
	if err = s.RenderAliases(); err != nil {
		return
	}
	s.timerStep("render and write aliases")
	s.ProcessShortcodes()
	s.timerStep("render shortcodes")
	s.timerStep("absolute URLify")
	if err = s.RenderIndexes(); err != nil {
		return
	}
	s.RenderIndexesIndexes()
	s.timerStep("render and write indexes")
	s.RenderLists()
	s.timerStep("render and write lists")
	if err = s.RenderPages(); err != nil {
		return
	}
	s.timerStep("render and write pages")
	if err = s.RenderHomePage(); err != nil {
		return
	}
	s.timerStep("render and write homepage")
	return
}

func (s *Site) checkDescriptions() {
	for _, p := range s.Pages {
		if len(p.Description) < 60 {
			fmt.Println(p.FileName + " ")
		}
	}
}

func (s *Site) initialize() (err error) {
	if err = s.checkDirectories(); err != nil {
		return err
	}

	staticDir := s.Config.GetAbsPath(s.Config.StaticDir + "/")

	s.Source = &source.Filesystem{
		AvoidPaths: []string{staticDir},
		Base:       s.absContentDir(),
	}

	s.initializeSiteInfo()

	s.Shortcodes = make(map[string]ShortcodeFunc)
	return
}

func (s *Site) initializeSiteInfo() {
	s.Info = SiteInfo{
		BaseUrl: template.URL(s.Config.BaseUrl),
		Title:   s.Config.Title,
		Recent:  &s.Pages,
		Config:  &s.Config,
	}
}

// Check if File / Directory Exists
func exists(path string) (bool, error) {
	_, err := os.Stat(path)
	if err == nil {
		return true, nil
	}
	if os.IsNotExist(err) {
		return false, nil
	}
	return false, err
}

func (s *Site) absLayoutDir() string {
	return s.Config.GetAbsPath(s.Config.LayoutDir)
}

func (s *Site) absContentDir() string {
	return s.Config.GetAbsPath(s.Config.ContentDir)
}

func (s *Site) absPublishDir() string {
	return s.Config.GetAbsPath(s.Config.PublishDir)
}

func (s *Site) checkDirectories() (err error) {
	if b, _ := dirExists(s.absLayoutDir()); !b {
		return fmt.Errorf("No layout directory found, expecting to find it at " + s.absLayoutDir())
	}
	if b, _ := dirExists(s.absContentDir()); !b {
		return fmt.Errorf("No source directory found, expecting to find it at " + s.absContentDir())
	}
	return
}

func (s *Site) ProcessShortcodes() {
	for _, page := range s.Pages {
		page.Content = template.HTML(ShortcodesHandle(string(page.Content), page, s.Tmpl))
	}
}

func (s *Site) CreatePages() (err error) {
	if s.Source == nil {
		return fmt.Errorf("No source files found in", s.absContentDir())
	}
	if len(s.Source.Files()) < 1 {
		return fmt.Errorf("No source files found in", s.absContentDir())
	}
	for _, file := range s.Source.Files() {
		page, err := ReadFrom(file.Contents, file.LogicalName)
		if err != nil {
			return err
		}
		page.Site = s.Info
		page.Tmpl = s.Tmpl
		page.Section = file.Section
		page.Dir = file.Dir
		if s.Config.BuildDrafts || !page.Draft {
			s.Pages = append(s.Pages, page)
		}
	}

	s.Pages.Sort()
	return
}

func (s *Site) BuildSiteMeta() (err error) {
	s.Indexes = make(IndexList)
	s.Sections = make(Index)

	for _, plural := range s.Config.Indexes {
		s.Indexes[plural] = make(Index)
		for _, p := range s.Pages {
			vals := p.GetParam(plural)

			if vals != nil {
				v, ok := vals.([]string)
				if ok {
					for _, idx := range v {
						s.Indexes[plural].Add(idx, p)
					}
				} else {
					if s.Config.Verbose {
						fmt.Fprintf(os.Stderr, "Invalid %s in %s\n", plural, p.File.FileName)
					}
				}
			}
		}
		for k, _ := range s.Indexes[plural] {
			s.Indexes[plural][k].Sort()
		}
	}

	for _, p := range s.Pages {
		s.Sections.Add(p.Section, p)
	}

	for k, _ := range s.Sections {
		s.Sections[k].Sort()
	}

	s.Info.Indexes = s.Indexes.BuildOrderedIndexList()

	if len(s.Pages) == 0 {
		return
	}
	s.Info.LastChange = s.Pages[0].Date

	// populate pages with site metadata
	for _, p := range s.Pages {
		p.Site = s.Info
	}

	return
}

func (s *Site) possibleIndexes() (indexes []string) {
	for _, p := range s.Pages {
		for k, _ := range p.Params {
			if !inStringArray(indexes, k) {
				indexes = append(indexes, k)
			}
		}
	}
	return
}

func inStringArray(arr []string, el string) bool {
	for _, v := range arr {
		if v == el {
			return true
		}
	}
	return false
}

func (s *Site) RenderAliases() error {
	for _, p := range s.Pages {
		for _, a := range p.Aliases {
			plink, err := p.Permalink()
			if err != nil {
				return err
			}
			if err := s.WriteAlias(a, template.HTML(plink)); err != nil {
				return err
			}
		}
	}
	return nil
}

func (s *Site) RenderPages() (err error) {
	for _, p := range s.Pages {
		var layout string

		if !p.IsRenderable() {
			layout = "__" + p.TargetPath()
			_, err := s.Tmpl.New(layout).Parse(string(p.Content))
			if err != nil {
				return err
			}
		} else {
			layout = p.Layout()
		}

		content, err := s.RenderThingOrDefault(p, layout, "_default/single.html")
		if err != nil {
			return err
		}
		err = s.WritePublic(p.TargetPath(), content)
		if err != nil {
			return err
		}
	}
	return nil
}

func (s *Site) RenderIndexes() error {
	for singular, plural := range s.Config.Indexes {
		for k, o := range s.Indexes[plural] {
			n := s.NewNode()
			n.Title = strings.Title(k)
			url := helpers.Urlize(plural + "/" + k)
			n.Url = url + ".html"
			plink := n.Url
			n.Permalink = permalink(s, plink)
			n.RSSlink = permalink(s, url+".xml")
			n.Date = o[0].Date
			n.Data[singular] = o
			n.Data["Pages"] = o
			layout := "indexes/" + singular + ".html"
			x, err := s.RenderThing(n, layout)
			if err != nil {
				return err
			}

			var base string
			base = plural + "/" + k
			err = s.WritePublic(base+".html", x)
			if err != nil {
				return err
			}

			if a := s.Tmpl.Lookup("rss.xml"); a != nil {
				// XML Feed
				y := s.NewXMLBuffer()
				n.Url = helpers.Urlize(plural + "/" + k + ".xml")
				n.Permalink = permalink(s, n.Url)
				s.Tmpl.ExecuteTemplate(y, "rss.xml", n)
				err = s.WritePublic(base+".xml", y)
				if err != nil {
					return err
				}
			}
		}
	}
	return nil
}

func (s *Site) RenderIndexesIndexes() (err error) {
	layout := "indexes/indexes.html"
	if s.Tmpl.Lookup(layout) != nil {
		for singular, plural := range s.Config.Indexes {
			n := s.NewNode()
			n.Title = strings.Title(plural)
			url := helpers.Urlize(plural)
			n.Url = url + "/index.html"
			n.Permalink = permalink(s, n.Url)
			n.Data["Singular"] = singular
			n.Data["Plural"] = plural
			n.Data["Index"] = s.Indexes[plural]
			n.Data["OrderedIndex"] = s.Info.Indexes[plural]

			x, err := s.RenderThing(n, layout)
			if err != nil {
				return err
			}

			err = s.WritePublic(plural+"/index.html", x)
			if err != nil {
				return err
			}
		}
	}
	return
}

func (s *Site) RenderLists() error {
	for section, data := range s.Sections {
		n := s.NewNode()
		n.Title = strings.Title(inflect.Pluralize(section))
		n.Url = helpers.Urlize(section + "/" + "index.html")
		n.Permalink = permalink(s, n.Url)
		n.RSSlink = permalink(s, section+".xml")
		n.Date = data[0].Date
		n.Data["Pages"] = data
		layout := "indexes/" + section + ".html"

		content, err := s.RenderThingOrDefault(n, layout, "_default/index.html")
		if err != nil {
			return err
		}
		err = s.WritePublic(section, content)
		if err != nil {
			return err
		}

		if a := s.Tmpl.Lookup("rss.xml"); a != nil {
			// XML Feed
			n.Url = helpers.Urlize(section + ".xml")
			n.Permalink = template.HTML(string(n.Site.BaseUrl) + n.Url)
			y := s.NewXMLBuffer()
			s.Tmpl.ExecuteTemplate(y, "rss.xml", n)
			err = s.WritePublic(section+"/index.xml", y)
			return err
		}
	}
	return nil
}

func (s *Site) RenderHomePage() error {

	n := s.NewNode()
	n.Title = n.Site.Title
	n.Url = helpers.Urlize(string(n.Site.BaseUrl))
	n.RSSlink = permalink(s, "index.xml")
	n.Permalink = permalink(s, "")
	if len(s.Pages) > 0 {
		n.Date = s.Pages[0].Date
		if len(s.Pages) < 9 {
			n.Data["Pages"] = s.Pages
		} else {
			n.Data["Pages"] = s.Pages[:9]
		}
	}
	x, err := s.RenderThing(n, "index.html")
	if err != nil {
		return err
	}
	err = s.WritePublic("/", x)
	if err != nil {
		return err
	}

	if a := s.Tmpl.Lookup("rss.xml"); a != nil {
		// XML Feed
		n.Url = helpers.Urlize("index.xml")
		n.Title = "Recent Content"
		n.Permalink = permalink(s, "index.xml")
		y := s.NewXMLBuffer()
		s.Tmpl.ExecuteTemplate(y, "rss.xml", n)
		err = s.WritePublic("index.xml", y)
		return err
	}

	if a := s.Tmpl.Lookup("404.html"); a != nil {
		n.Url = helpers.Urlize("404.html")
		n.Title = "404 Page not found"
		n.Permalink = permalink(s, "404.html")
		x, err := s.RenderThing(n, "404.html")
		if err != nil {
			return err
		}
		err = s.WritePublic("404.html", x)
		return err
	}

	return nil
}

func (s *Site) Stats() {
	fmt.Printf("%d pages created \n", len(s.Pages))
	for _, pl := range s.Config.Indexes {
		fmt.Printf("%d %s index created\n", len(s.Indexes[pl]), pl)
	}
}

func permalink(s *Site, plink string) template.HTML {
	base, err := url.Parse(string(s.Config.BaseUrl))
	if err != nil {
		panic(err)
	}

	path, err := url.Parse(plink)
	if err != nil {
		panic(err)
	}

	return template.HTML(MakePermalink(base, path).String())
}

func (s *Site) NewNode() *Node {
	return &Node{
		Data: make(map[string]interface{}),
		Site: s.Info,
	}
}

func (s *Site) RenderThing(d interface{}, layout string) (*bytes.Buffer, error) {
	if s.Tmpl.Lookup(layout) == nil {
		return nil, fmt.Errorf("Layout not found: %s", layout)
	}
	buffer := new(bytes.Buffer)
	err := s.Tmpl.ExecuteTemplate(buffer, layout, d)
	return buffer, err
}

func (s *Site) RenderThingOrDefault(d interface{}, layout string, defaultLayout string) (*bytes.Buffer, error) {
	content, err := s.RenderThing(d, layout)
	if err != nil {
		var err2 error
		content, err2 = s.RenderThing(d, defaultLayout)
		if err2 == nil {
			return content, err2
		}
	}
	return content, err
}

func (s *Site) NewXMLBuffer() *bytes.Buffer {
	header := "<?xml version=\"1.0\" encoding=\"utf-8\" standalone=\"yes\" ?>\n"
	return bytes.NewBufferString(header)
}

func (s *Site) initTarget() {
	if s.Target == nil {
		s.Target = &target.Filesystem{
			PublishDir: s.absPublishDir(),
			UglyUrls:   s.Config.UglyUrls,
		}
	}
}

func (s *Site) WritePublic(path string, content io.Reader) (err error) {
	s.initTarget()

	if s.Config.Verbose {
		fmt.Println(path)
	}

	if s.Transformer == nil {
		s.Transformer = &transform.Transformer{BaseURL: s.Config.BaseUrl}
	}
	final := new(bytes.Buffer)
	s.Transformer.Apply(content, final)
	return s.Target.Publish(path, final)
}

func (s *Site) WriteAlias(path string, permalink template.HTML) (err error) {
	if s.Alias == nil {
		s.initTarget()
		s.Alias = &target.HTMLRedirectAlias{
			PublishDir: s.absPublishDir(),
		}
	}

	if s.Config.Verbose {
		fmt.Println(path)
	}

	return s.Alias.Publish(path, permalink)
}