// 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/helpers"
    "github.com/spf13/hugo/source"
    "github.com/spf13/hugo/target"
    "github.com/spf13/hugo/template/bundle"
    "github.com/spf13/hugo/transform"
    "github.com/spf13/nitro"
    "html/template"
    "io"
    "net/url"
    "os"
    "strings"
    "time"
)

var _ = transform.AbsURL

var DefaultTimer *nitro.B

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

// Site contains all the information relevant 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.  The canonical path can be overruled based on a pattern.
//
// 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
    Target     target.Output
    Alias      target.AliasPublisher
    Completed  chan bool
    RunMode    runmode
    params     map[string]interface{}
}

type SiteInfo struct {
    BaseUrl    template.URL
    Indexes    IndexList
    Recent     *Pages
    LastChange time.Time
    Title      string
    Config     *Config
    Permalinks PermalinkOverrides
    Params     map[string]interface{}
}

type runmode struct {
    Watching bool
}

func (s *Site) Running() bool {
    return s.RunMode.Watching
}

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) {
    if err = s.initialize(); err != nil {
        return
    }
    s.prepTemplates()
    s.timerStep("initialize & template prep")
    if err = s.CreatePages(); err != nil {
        return
    }
    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")
    if err = s.RenderIndexes(); err != nil {
        return
    }
    s.timerStep("render and write indexes")
    s.RenderIndexesIndexes()
    s.timerStep("render & write index indexes")
    if err = s.RenderLists(); err != nil {
        return
    }
    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,
        Params:     s.Config.Params,
        Permalinks: s.Config.Permalinks,
    }
}

// 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) CreatePages() (err error) {
    if s.Source == nil {
        panic(fmt.Sprintf("s.Source not set %s", s.absContentDir()))
    }
    if len(s.Source.Files()) < 1 {
        return fmt.Errorf("No source files found in %s", 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

        //Handling short codes prior to Conversion to HTML
        page.ProcessShortcodes(s.Tmpl)

        err = page.Convert()
        if err != nil {
            return err
        }

        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)
            weight := p.GetParam(plural + "_weight")
            if weight == nil {
                weight = 0
            }

            if vals != nil {
                v, ok := vals.([]string)
                if ok {
                    for _, idx := range v {
                        x := WeightedPage{weight.(int), p}

                        s.Indexes[plural].Add(idx, x)
                    }
                } 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 i, p := range s.Pages {
        s.Sections.Add(p.Section, WeightedPage{s.Pages[i].Weight, s.Pages[i]})
    }

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

    s.Info.Indexes = s.Indexes

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

        err := s.render(p, p.TargetPath(), layout...)
        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].Page.Date
            n.Data[singular] = o
            n.Data["Pages"] = o.Pages()
            layout := "indexes/" + singular + ".html"

            var base string
            base = plural + "/" + k
            err := s.render(n, base+".html", layout)
            if err != nil {
                return err
            }

            if a := s.Tmpl.Lookup("rss.xml"); a != nil {
                // XML Feed
                n.Url = helpers.Urlize(plural + "/" + k + ".xml")
                n.Permalink = permalink(s, n.Url)
                err := s.render(n, base+".xml", "rss.xml")
                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]
            // keep the following just for legacy reasons
            n.Data["OrderedIndex"] = s.Indexes[plural]

            err := s.render(n, plural+"/index.html", layout)
            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].Page.Date
        n.Data["Pages"] = data.Pages()
        layout := "indexes/" + section + ".html"

        err := s.render(n, section, layout, "_default/indexes.html")
        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)
            err = s.render(n, section+".xml", "rss.xml")
            if err != nil {
                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, "")
    n.Data["Pages"] = s.Pages
    err := s.render(n, "/", "index.html")
    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")
        high := 50
        if len(s.Pages) < high {
            high = len(s.Pages)
        }
        n.Data["Pages"] = s.Pages[:high]
        if len(s.Pages) > 0 {
            n.Date = s.Pages[0].Date
        }
        err := s.render(n, ".xml", "rss.xml")
        if err != nil {
            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")
        return s.render(n, "404.html", "404.html")
    }

    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) render(d interface{}, out string, layouts ...string) (err error) {

    layout := s.findFirstLayout(layouts...)
    if layout == "" {
        if s.Config.Verbose {
            fmt.Printf("Unable to locate layout: %s\n", layouts)
        }
        return
    }

    transformLinks := transform.NewEmptyTransforms()

    if s.Config.CanonifyUrls {
        absURL, err := transform.AbsURL(s.Config.BaseUrl)
        if err != nil {
            return err
        }
        transformLinks = append(transformLinks, absURL...)
    }

    transformer := transform.NewChain(transformLinks...)

    var renderBuffer *bytes.Buffer

    if strings.HasSuffix(out, ".xml") {
        renderBuffer = s.NewXMLBuffer()
    } else {
        renderBuffer = new(bytes.Buffer)
    }

    err = s.renderThing(d, layout, renderBuffer)
    if err != nil {
        // Behavior here should be dependent on if running in server or watch mode.
        fmt.Println(fmt.Errorf("Rendering error: %v", err))
        if !s.Running() {
            os.Exit(-1)
        }
    }

    var outBuffer = new(bytes.Buffer)
    if strings.HasSuffix(out, ".xml") {
        outBuffer = renderBuffer
    } else {
        transformer.Apply(outBuffer, renderBuffer)
    }

    return s.WritePublic(out, outBuffer)
}

func (s *Site) findFirstLayout(layouts ...string) (layout string) {
    for _, layout = range layouts {
        if s.Tmpl.Lookup(layout) != nil {
            return
        }
    }
    return ""
}

func (s *Site) renderThing(d interface{}, layout string, w io.Writer) error {
    // If the template doesn't exist, then return, but leave the Writer open
    if s.Tmpl.Lookup(layout) == nil {
        return fmt.Errorf("Layout not found: %s", layout)
    }
    //defer w.Close()
    return s.Tmpl.ExecuteTemplate(w, layout, d)
}

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, reader io.Reader) (err error) {
    s.initTarget()

    if s.Config.Verbose {
        fmt.Println(path)
    }
    return s.Target.Publish(path, reader)
}

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)
}