library/cmd/serve/api.go

package main

import (
	"encoding/json"
	"fmt"
	"io/fs"
	"net/http"

	"git.yetaga.in/alazyreader/library/media"
	"tailscale.com/client/tailscale"
	"tailscale.com/util/must"
)

type Router struct {
	static fs.FS
	lib    Library
	rcol   RecordCollection
}

type AdminRouter struct {
	static fs.FS
	lib    Library
	ts     *tailscale.LocalClient
}

func writeError[T any](w http.ResponseWriter) func(t T, err error) (T, bool) {
	return func(t T, err error) (T, bool) {
		if err != nil {
			http.Error(w, err.Error(), http.StatusInternalServerError)
		}
		return t, err != nil
	}
}

func writeJSON(w http.ResponseWriter, b []byte, status int) {
	w.Header().Set("Content-Type", "application/json; charset=utf-8")
	w.WriteHeader(status)
	w.Write(b)
	w.Write([]byte("\n"))
}

func (r *Router) ServeHTTP(w http.ResponseWriter, req *http.Request) {
	if req.URL.Path == "/api/records" {
		RecordsAPIHandler(r.rcol).ServeHTTP(w, req)
		return
	}
	if req.URL.Path == "/api/books" {
		BooksAPIHandler(r.lib).ServeHTTP(w, req)
		return
	}
	StaticHandler(r.static).ServeHTTP(w, req)
}

func (r *AdminRouter) ServeHTTP(w http.ResponseWriter, req *http.Request) {
	whois, _ := r.ts.WhoIs(req.Context(), req.RemoteAddr)
	switch req.URL.Path {
	case "/api/books":
		switch req.Method {
		case http.MethodGet:
			books, ok := writeError[[]media.Book](w)(r.lib.GetAllBooks(req.Context()))
			if !ok {
				return
			}
			b, ok := writeError[[]byte](w)(json.Marshal(books))
			if !ok {
				return
			}
			writeJSON(w, b, http.StatusOK)
		case http.MethodPost:
		default:
			badMethod(w)
		}
		return
	}
	w.Write([]byte(fmt.Sprintf("%+v", whois.UserProfile.DisplayName)))
	// StaticHandler(r.static).ServeHTTP(w, req)
}

func badMethod(w http.ResponseWriter) {
	writeJSON(w,
		must.Get(json.Marshal(struct{ Error string }{Error: "method not supported"})),
		http.StatusMethodNotAllowed)
}

func BooksAPIHandler(l Library) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		books, err := l.GetAllBooks(r.Context())
		if err != nil {
			http.Error(w, err.Error(), http.StatusInternalServerError)
			return
		}
		b, err := json.Marshal(books)
		if err != nil {
			http.Error(w, err.Error(), http.StatusInternalServerError)
			return

		}
		writeJSON(w, b, http.StatusOK)
	})
}

func RecordsAPIHandler(l RecordCollection) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		books, err := l.GetAllRecords(r.Context())
		if err != nil {
			http.Error(w, err.Error(), http.StatusInternalServerError)
			return
		}
		b, err := json.Marshal(books)
		if err != nil {
			http.Error(w, err.Error(), http.StatusInternalServerError)
			return
		}
		writeJSON(w, b, http.StatusOK)
	})
}

func StaticHandler(f fs.FS) http.Handler {
	return http.FileServer(http.FS(f))
}