package main

import (
	"database/sql"
	"log"
	"net/http"
	"os"
	"time"

	_ "github.com/lib/pq"

	"git.sr.ht/~sircmpwn/getopt"
	"github.com/99designs/gqlgen/graphql/handler"
	"github.com/99designs/gqlgen/graphql/playground"
	"github.com/go-chi/chi"
	"github.com/go-chi/chi/middleware"
	"github.com/prometheus/client_golang/prometheus"
	promcollectors "github.com/prometheus/client_golang/prometheus/collectors"
	"github.com/prometheus/client_golang/prometheus/promhttp"

	"git.sr.ht/~sircmpwn/searchhut/config"
	"git.sr.ht/~sircmpwn/searchhut/database"
	"git.sr.ht/~sircmpwn/searchhut/graph"
	"git.sr.ht/~sircmpwn/searchhut/graph/generated"
)

var durationMetric = prometheus.NewHistogramVec(
	prometheus.HistogramOpts{
		Name:    "query_duration_seconds",
		Help:    "GraphQL query latency in seconds.",
		Buckets: prometheus.DefBuckets,
	},
	nil,
)

func main() {
	debug := false
	opts, _, err := getopt.Getopts(os.Args, "d")
	if err != nil {
		log.Fatal(err)
	}
	for _, opt := range opts {
		switch opt.Option {
		case 'd':
			debug = true
		}
	}

	conf := config.Load()
	port, ok := conf.Get("searchhut::api", "bind")
	if !ok {
		port = ":8080"
	}

	connstr, ok := conf.Get("searchhut", "connection-string")
	if !ok {
		log.Fatal("Configuration missing connection string")
	}

	db, err := sql.Open("postgres", connstr)
	if err != nil {
		log.Fatal(err)
	}
	prometheus.DefaultRegisterer.Register(promcollectors.NewDBStatsCollector(db, "main"))

	prometheus.MustRegister(durationMetric)

	schema := generated.NewExecutableSchema(generated.Config{
		Resolvers: &graph.Resolver{},
	})
	srv := handler.NewDefaultServer(schema)

	router := chi.NewRouter()
	router.Use(database.Middleware(db))
	router.Use(middleware.RealIP)
	router.Use(middleware.Logger)
	router.Use(middleware.Timeout(10 * time.Second))

	router.With(promQueryMiddleware).Handle("/query", srv)
	if debug {
		router.Handle("/", playground.Handler("GraphQL playground", "/query"))
	}

	router.Handle("/metrics", promhttp.HandlerFor(prometheus.DefaultGatherer, promhttp.HandlerOpts{
		MaxRequestsInFlight: 10,
		Timeout:             10 * time.Second,
		EnableOpenMetrics:   true,
	}))

	log.Printf("Running server on %s", port)
	log.Fatal(http.ListenAndServe(port, router))
}

func promQueryMiddleware(next http.Handler) http.Handler {
	return promhttp.InstrumentHandlerDuration(durationMetric, next)
}