package yatwiki3

import (
	"database/sql"
	"errors"
	"fmt"
	"html/template"
	"log"
	"net/http"
	"net/url"
	"strings"
)

type WikiServer struct {
	db      *WikiDB
	opts    *ServerOptions
	pageTmp *template.Template
}

func NewWikiServer(opts *ServerOptions) (*WikiServer, error) {
	wdb, err := NewWikiDB(opts.DBFilePath)
	if err != nil {
		return nil, err
	}

	tmpl, err := template.New("yatwiki/page").Parse(pageTemplate)
	if err != nil {
		panic(err)
	}

	ws := WikiServer{
		db:      wdb,
		opts:    opts,
		pageTmp: tmpl,
	}
	return &ws, nil
}

func (this *WikiServer) Close() {
	this.db.Close()
}

func (this *WikiServer) ServeHTTP(w http.ResponseWriter, r *http.Request) {
	w.Header().Set("Server", "Yatwiki3")

	if r.Method == "GET" {
		if r.URL.Path == this.opts.ExpectBaseURL+"wiki.css" {
			w.Header().Set("Content-Type", "text/css")
			content, _ := wikiCssBytes()
			w.Write(content)
			return

		} else if r.URL.Path == this.opts.ExpectBaseURL+"highlight.js" {
			w.Header().Set("Content-Type", "application/javascript")
			content, _ := highlightJsBytes()
			w.Write(content)
			return

		} else if r.URL.Path == this.opts.ExpectBaseURL+"favicon.ico" && len(this.opts.FaviconFilePath) > 0 {
			w.Header().Set("Content-Type", "image/x-icon")
			http.ServeFile(w, r, this.opts.FaviconFilePath)
			return

		} else if r.URL.Path == this.opts.ExpectBaseURL+"formatting" {
			pto := DefaultPageTemplateOptions(this.opts)
			pto.CurrentPageName = "Formatting help"
			pto.Content = `
<h2>Formatting help</h2><br><br>
<ul>
	<li>[h]header[/h]</li>
	<li>[b]bold[/b]</li>
	<li>[u]underline[/u]</li>
	<li>[i]italic[/i]</li>
	<li>[s]strikethrough[/s]</li>
	<li>[spoiler]spoiler[/spoiler]</li>
	<li>[list] item [*] item [/list]</li>
	<li>[url=address]title[/url]</li>
	<li>[article=page name]title[/article] or [rev=id]title[/rev]</li>
	<li>[img]image-url[/img]</li>
	<li>[imgur]asdf.jpg[/imgur]</li>
	<li>[code]fixed width[/code]</li>
	<li>[section=header]content[/section]</li>
	<li>[html]raw html[/html]</li>
</ul>`
			this.servePageResponse(w, r, pto)
			return

		} else if r.URL.Path == this.opts.ExpectBaseURL+"index" {
			titles, err := this.db.ListTitles()
			if err != nil {
				this.serveInternalError(w, r, err)
				return
			}

			totalRevs, err := this.db.TotalRevisions()
			if err != nil {
				this.serveInternalError(w, r, err)
				return
			}

			content := fmt.Sprintf(`<h2>Article Index</h2><br><em>There are %d edits to %d pages.</em><br><br><ul>`, totalRevs, len(titles))
			for _, title := range titles {
				content += `<li><a href="` + template.HTMLEscapeString(this.opts.ExpectBaseURL+`view/`+url.QueryEscape(title)) + `">` + template.HTMLEscapeString(title) + `</a></li>`
			}
			content += `</ul>`

			pto := DefaultPageTemplateOptions(this.opts)
			pto.CurrentPageName = "Index"
			pto.Content = template.HTML(content)
			this.servePageResponse(w, r, pto)
			return

		} else if strings.HasPrefix(r.URL.Path, this.opts.ExpectBaseURL+"view/") {
			articleTitle, err := url.QueryUnescape(r.URL.Path[len(this.opts.ExpectBaseURL+"view/"):])
			if err != nil {
				this.serveErrorMessage(w, err)
				return
			}

			a, err := this.db.GetLatestVersion(articleTitle)
			if err != nil {

				if err == sql.ErrNoRows {
					// Yatwiki2 always required a trailing slash at the end of the URL
					// If this was an old link, it might not be present.
					// Redirect if possible
					if len(articleTitle) > 0 && articleTitle[len(articleTitle)-1] == '/' {
						this.serveRedirect(w, this.opts.ExpectBaseURL+"view/"+url.QueryEscape(articleTitle[0:len(articleTitle)-1]))
						return
					}

					this.serveErrorHTMLMessage(w, this.noSuchArticleError(articleTitle))
					return
				}
				this.serveErrorMessage(w, err)
				return
			}

			pto := DefaultPageTemplateOptions(this.opts)
			pto.CurrentPageName = articleTitle
			pto.CurrentPageIsArticle = true

			bcr := NewBBCodeRenderer(this.opts.ExpectBaseURL)
			pto.Content = bcr.RenderHTML(string(a.Body))
			pto.LoadCodeResources = bcr.CodePresent

			this.servePageResponse(w, r, pto)
			return

		}

	}

	// No match? Add 'Page not found' to next session response, and redirect to homepage
	this.serveErrorMessage(w, errors.New("Page not found"))

}

func (this *WikiServer) noSuchArticleError(title string) template.HTML {
	return template.HTML(`No such article exists. <a href="` + this.opts.ExpectBaseURL + `modify/` + template.HTMLEscapeString(url.QueryEscape(title)) + `">Click here</a> to create it.`)
}

func (this *WikiServer) serveErrorMessage(w http.ResponseWriter, message error) {
	this.serveErrorHTMLMessage(w, template.HTML(template.HTMLEscapeString(message.Error())))
}

func (this *WikiServer) serveInternalError(w http.ResponseWriter, r *http.Request, e error) {
	log.Printf("Internal error from %s while accessing %s(%s): %s", r.RemoteAddr, r.Method, r.URL.Path, e.Error())
	http.Error(w, "An internal error occurred. Please ask an administrator to check the log file.", 500)
}

func (this *WikiServer) serveErrorHTMLMessage(w http.ResponseWriter, msg template.HTML) {
	this.serveRedirect(w, this.opts.ExpectBaseURL+"view/"+url.QueryEscape(this.opts.DefaultPage)+"?error="+url.QueryEscape(string(msg)))
}

func (this *WikiServer) serveRedirect(w http.ResponseWriter, location string) {
	w.Header().Set("Location", location)
	w.WriteHeader(302) // moved (not permanently)
}

func (this *WikiServer) servePageResponse(w http.ResponseWriter, r *http.Request, pto *pageTemplateOptions) {
	pto.SessionMessage = template.HTML(r.URL.Query().Get("error")) // FIXME reflected XSS (although Chrome automatically blocks it..)

	err := this.pageTmp.Execute(w, pto)
	if err != nil {
		log.Println(err.Error())
	}
}