page.go

package web

import (
	"encoding/json"
	"fmt"
	"log"
	"net/http"
	"strings"

	"github.com/julienschmidt/httprouter"

	"github.com/alicebob/verssion/core"
)

func allPages(db core.DB, w http.ResponseWriter, r *http.Request) {
	if url := r.FormValue("page"); url != "" {
		// "new page" form
		if page := core.WikiBasePage(url); page != "" {
			w.Header().Set("Location", "/p/"+page+"/")
			w.WriteHeader(301)
			return
		}
	}
	qorder := r.FormValue("order")
	order := core.Alphabet
	if qorder == "spider" {
		order = core.SpiderT
	}
	all, err := db.Current(0, order)
	if err != nil {
		log.Printf("current all: %s", err)
		http.Error(w, http.StatusText(500), 500)
		return
	}
	runTmpl(w, allPagesTempl, map[string]interface{}{
		"title":   "Pages overview",
		"current": "allpages",
		"pages":   all,
		"order":   qorder,
	})
}

// PageJSON is returned for ?format=json
type PageJSON struct {
	Page          string `json:"page"`
	Title         string `json:"title"`
	StableVersion string `json:"stable_version"`
	Homepage      string `json:"homepage"`
	WikipediaURL  string `json:"wikipedia_url"`
}

// pageHandler deal with everything under `/p/`.
func pageHandler(base string, db core.DB, spider core.Spider) httprouter.Handle {
	return func(w http.ResponseWriter, r *http.Request, p httprouter.Params) {
		page := p.ByName("page")
		if page == "" || page == "/" {
			allPages(db, w, r)
			return
		}
		page = page[1:] // prefix /
		if !strings.HasSuffix(page, "/") {
			w.Header().Set("Location", "/p/"+page+"/")
			w.WriteHeader(301)
			return
		}
		page = page[:len(page)-1] // post /
		cur, err := StoreSpider(db, spider, page)
		if err != nil {
			switch e := err.(type) {
			case core.ErrNotFound:
				log.Printf("not found: %s", err)
				w.WriteHeader(404)
				switch r.FormValue("format") {
				case "json":
				default:
					runTmpl(w, pageNotFoundTempl, map[string]interface{}{
						"title":     core.Title(e.Page),
						"current":   "",
						"wikipedia": WikiURL(e.Page),
						"page":      e.Page,
					})
				}
			case core.ErrNoVersion:
				switch r.FormValue("format") {
				case "json":
					w.WriteHeader(404)
				default:
					runTmpl(w, noVersionTempl, map[string]interface{}{
						"title":   core.Title(e.Page),
						"current": "",
						"page":    e.Page,
					})
				}
			default:
				log.Printf("update %q: %s", page, err)
				http.Error(w, http.StatusText(500), 500)
			}
			return
		}

		if page != cur.Page {
			w.Header().Set("Location", fmt.Sprintf("/p/%s/", cur.Page))
			w.WriteHeader(302)
			return
		}

		vs, err := db.History(cur.Page)
		if err != nil {
			log.Printf("history: %s", err)
			http.Error(w, http.StatusText(500), 500)
			return
		}

		switch r.FormValue("format") {
		case "json":
			w.Header().Set("Content-Type", "application/json")
			json.NewEncoder(w).Encode(PageJSON{
				Page:          cur.Page,
				Title:         core.Title(cur.Page),
				WikipediaURL:  WikiURL(cur.Page),
				StableVersion: cur.StableVersion,
				Homepage:      cur.Homepage,
			})
		case "", "html":
			runTmpl(w, pageTempl, map[string]interface{}{
				"title":     core.Title(cur.Page),
				"current":   "",
				"atom":      adhocURL(base, []string{cur.Page}),
				"json":      fmt.Sprintf("%s/p/%s/?format=json", base, cur.Page),
				"wikipedia": WikiURL(cur.Page),
				"page":      cur,
				"versions":  vs,
			})
		default:
			http.Error(w, http.StatusText(400), 400)
		}
	}
}

var (
	allPagesTempl = withPage(`
{{define "hero"}}
	<h1>All Known Pages</h1>
{{end}}

{{define "body"}}
<table class="table-responsive table-1">
	<tbody>
	{{- range .pages}}
		<tr>
			<td><a href="./{{.Page}}/" title="{{.Page}}">{{title .Page}}</a></td>
			<td>{{version .StableVersion}}</td>
		</tr>
	{{- end}}
	</tbody>
</table>

<p>
Order by: {{if eq .order "spider"}}
	Update - <a href="./">Alphabetical</a>
{{else}}
	<a href="./?order=spider">Update</a> - Alphabetical
{{end}}
</p>

<h4>New page</h4>
<p>You're missing something? Add a wikipedia page. Give either the full URL or the title of the page.</p>
<form class="form pages-form" method="GET">
<input type="text" name="page"/>
<button type="submit" class="btn">go</button>
</form>
{{- end}}
`)

	pageTempl = withPage(`
{{define "head"}}
	<link rel="alternate" type="application/atom+xml" title="Atom 1.0" href="{{.atom}}"/>
	<link rel="alternate" type="application/json" title="JSON" href="{{.json}}"/>
{{- end}}

{{define "hero"}}
<h1>{{title .page.Page}}</h1>
<dl>
	<dt>Wikipedia</dt>
	<dd><i class="fa fa-wikipedia-w"></i><a href="{{.wikipedia}}">{{.wikipedia}}</a></dd>
	<dt>Homepage</dt>
	<dd><i class="fa fa-external-link"></i>{{with .page.Homepage}}{{link .}}{{- end}}</dd>
	<dt>Current stable version</dt>
	<dd>{{with .page.StableVersion}}{{version .}}{{- end}}</dd>
</dl>
{{end}}

{{define "body"}}
<h3>Version history</h3>
	
<table class="table-responsive table-2">
	<thead>
		<tr>
			<td class="hidden-xs"><strong>Spider timestamp</strong></td>
			<td><strong>Version</strong></td>
		</tr>
	</thead>
	<tbody>
	{{- range .versions}}
		<tr>
			<td class="hidden-xs">{{.T.Format "2006-01-02 15:04 UTC"}}</td>
			<td>{{version .StableVersion}}</td>
		</tr>
	{{- end}}
	</tbody>
</table>
<p>RSS link: <a href="{{.atom}}">Atom feed</a></p>
<div class="soft-footer">
	<p>Version numbers are retrieved from Wikipedia, and are licensed under Creative Commons.</p>
	<p>If the current stable version is out of date, please edit <a href="{{.wikipedia}}">Wikipedia</a>.</p>
	<p>Latest spider check: {{if not .page.T.IsZero}}{{.page.T.Format "2006-01-02 15:04 UTC"}}{{- end}}</p>
</div>
{{end}}
`)

	pageNotFoundTempl = withPage(`
{{define "hero"}}
	<h1>{{.page}}</h1>
{{end}}
{{define "body"}}
	<p>Page not found: {{.page}}</p>
	<p>Maybe you can create it on <a href="{{.wikipedia}}">Wikipedia</a></p>
{{end}}
`)

	noVersionTempl = withPage(`
{{define "hero"}}
	<h1>{{.page}}</h1>
{{end}}

{{define "body"}}
	<p>No version found for <b>{{.page}}</b></p>
	<p>Maybe this is a disambiguation page? <a href="https://en.wikipedia.org/w/index.php?search={{.page}}">Search</a> on Wikipedia.</p>
{{end}}
`)
)