package internal

import (
	"errors"
	"fmt"
	"html/template"
	"net/http"
	"strings"

	rice "github.com/GeertJohan/go.rice"
	"github.com/gomarkdown/markdown"
	"github.com/gomarkdown/markdown/html"
	"github.com/gomarkdown/markdown/parser"
	"github.com/james4k/fmatter"
	"github.com/julienschmidt/httprouter"
	log "github.com/sirupsen/logrus"
)

const (
	MediaResolution  = 720 // 720x576
	AvatarResolution = 360 // 360x360
	AsyncTaskLimit   = 5
	MaxFailedLogins  = 3 // By default 3 failed login attempts per 5 minutes
)

var (
	ErrFeedImposter = errors.New("error: imposter detected, you do not own this feed")
)

func (s *Server) NotFoundHandler(w http.ResponseWriter, r *http.Request) {
	if r.Header.Get("Accept") == "application/json" {
		w.Header().Set("Content-Type", "application/json")
		http.Error(w, "Endpoint Not Found", http.StatusNotFound)
		return
	}

	ctx := NewContext(s.config, s.db, r)
	ctx.Title = "Page Not Found"
	w.WriteHeader(http.StatusNotFound)
	s.render("404", w, ctx)
}

type FrontMatter struct {
	Title string
}

// PageHandler ...
func (s *Server) PageHandler(name string) httprouter.Handle {
	box := rice.MustFindBox("pages")
	mdTpl := box.MustString(fmt.Sprintf("%s.md", name))

	return func(w http.ResponseWriter, r *http.Request, _ httprouter.Params) {
		ctx := NewContext(s.config, s.db, r)

		md, err := RenderString(mdTpl, ctx)
		if err != nil {
			log.WithError(err).Errorf("error rendering page %s", name)
			ctx.Error = true
			ctx.Message = "Error loading help page! Please contact support."
			s.render("error", w, ctx)
			return
		}

		var frontmatter FrontMatter
		content, err := fmatter.Read([]byte(md), &frontmatter)
		if err != nil {
			log.WithError(err).Error("error parsing front matter")
			ctx.Error = true
			ctx.Message = "Error loading page! Please contact support."
			s.render("error", w, ctx)
			return
		}

		extensions := parser.CommonExtensions | parser.AutoHeadingIDs
		p := parser.NewWithExtensions(extensions)

		htmlFlags := html.CommonFlags
		opts := html.RendererOptions{
			Flags:     htmlFlags,
			Generator: "",
		}
		renderer := html.NewRenderer(opts)

		html := markdown.ToHTML(content, p, renderer)

		var title string

		if frontmatter.Title != "" {
			title = frontmatter.Title
		} else {
			title = strings.Title(name)
		}
		ctx.Title = title

		ctx.Page = name
		ctx.Content = template.HTML(html)

		s.render("page", w, ctx)
	}
}