package main

import (
	"context"
	"errors"
	"fmt"
	"log/slog"
	"net/http"
	"os"
	"os/signal"
	"time"

	"git.loyso.art/frx/kurious/internal/common/client/sravni"
	"git.loyso.art/frx/kurious/internal/common/config"
	"git.loyso.art/frx/kurious/internal/common/generator"
	"git.loyso.art/frx/kurious/internal/common/xcontext"
	"git.loyso.art/frx/kurious/internal/kurious/adapters"
	xhttp "git.loyso.art/frx/kurious/internal/kurious/ports/http"
	"git.loyso.art/frx/kurious/internal/kurious/service"
	"golang.org/x/sync/errgroup"

	"github.com/gorilla/mux"
)

func main() {
	ctx, cancel := signal.NotifyContext(context.Background(), os.Interrupt)
	defer cancel()

	err := app(ctx)
	if err != nil {
		println(err.Error())
		os.Exit(1)
	}
}

func app(ctx context.Context) error {
	var cfgpath string
	if len(os.Args) > 1 {
		cfgpath = os.Args[1]
	} else {
		cfgpath = "config.json"
	}

	cfg, err := readFromFile(cfgpath, defaultConfig)
	if err != nil {
		return fmt.Errorf("reading config from file: %w", err)
	}

	log := config.NewSLogger(cfg.Log)

	sravniClient, err := sravni.NewClient(ctx, log, false)
	if err != nil {
		return fmt.Errorf("unable to make new sravni client: %w", err)
	}

	mainPageState, err := sravniClient.GetMainPageState()
	if err != nil {
		return fmt.Errorf("getting main page state: %w", err)
	}

	dictionaries := mainPageState.Props.InitialReduxState.Dictionaries.Data

	dictFieldsAsMap := func(fields ...sravni.Field) map[string]string {
		out := make(map[string]string, len(fields))
		for _, field := range fields {
			out[field.Value] = field.Name
		}
		return out
	}

	courseThematcisMapped := dictFieldsAsMap(dictionaries.CourseThematics.Fields...)
	learningTypeMapped := dictFieldsAsMap(dictionaries.LearningType.Fields...)

	mapper := adapters.NewMemoryMapper(courseThematcisMapped, learningTypeMapped)

	app, err := service.NewApplication(ctx, service.ApplicationConfig{
		LogConfig: cfg.Log,
		YDB:       cfg.YDB,
	}, mapper)
	if err != nil {
		return fmt.Errorf("making new application: %w", err)
	}

	httpAPI := xhttp.NewServer(app, log.With(slog.String("component", "http")))
	httpServer := setupHTTP(cfg.HTTP, httpAPI, log)

	eg, egctx := errgroup.WithContext(ctx)
	eg.Go(func() error {
		xcontext.LogInfo(
			ctx, log, "serving http",
			slog.String("addr", httpServer.Addr),
		)

		err := httpServer.ListenAndServe()
		if err != nil {
			if !errors.Is(err, http.ErrServerClosed) {
				return fmt.Errorf("listening http: %w", err)
			}
		}
		return nil
	})
	eg.Go(func() error {
		<-egctx.Done()

		xcontext.LogInfo(ctx, log, "trying to shutdown http")
		sdctx, sdcancel := context.WithTimeout(context.Background(), time.Second*10)
		defer sdcancel()
		err := httpServer.Shutdown(sdctx)
		if err != nil {
			return fmt.Errorf("shutting down the server: %w", err)
		}

		xcontext.LogInfo(ctx, log, "server closed successfuly")
		return nil
	})

	return eg.Wait()
}

func setupHTTP(cfg config.HTTP, srv xhttp.Server, log *slog.Logger) *http.Server {
	router := mux.NewRouter()

	coursesAPI := srv.Courses()

	router.Use(mux.CORSMethodMiddleware(router))
	router.Use(middlewareLogger(log))
	router.HandleFunc("/updatedesc", coursesAPI.UdpateDescription).Methods(http.MethodPost)
	coursesRouter := router.PathPrefix("/courses").Subrouter()
	coursesRouter.HandleFunc("/", coursesAPI.List).Methods(http.MethodGet)

	courseRouter := coursesRouter.PathPrefix("/{course_id}").Subrouter()
	courseRouter.HandleFunc("/", coursesAPI.Get).Methods(http.MethodGet)
	courseRouter.HandleFunc("/short", coursesAPI.GetShort).Methods(http.MethodGet)
	courseRouter.HandleFunc("/editdesc", coursesAPI.RenderEditDescription).Methods(http.MethodGet)

	courseRouter.HandleFunc("/description", coursesAPI.UpdateCourseDescription).Methods(http.MethodPut)

	if cfg.MountLive {
		fs := http.FileServer(http.Dir("./assets/kurious/static/"))
		router.PathPrefix("/static/").Handler(http.StripPrefix("/static/", fs))
	}

	return &http.Server{
		Addr:    cfg.ListenAddr,
		Handler: router,
	}
}

func middlewareLogger(log *slog.Logger) mux.MiddlewareFunc {
	return func(next http.Handler) http.Handler {
		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
			ctx := r.Context()
			requestID := r.Header.Get("x-request-id")
			if requestID == "" {
				requestID = generator.RandomInt64ID()
			}
			ctx = xcontext.WithLogFields(ctx, slog.String("request_id", requestID))

			xcontext.LogInfo(
				ctx, log, "incoming request",
				slog.String("method", r.Method),
				slog.String("path", r.URL.Path),
			)

			start := time.Now()
			next.ServeHTTP(w, r.WithContext(ctx))
			elapsed := time.Since(start)

			xcontext.LogInfo(
				ctx, log, "request processed",
				slog.Duration("elapsed", elapsed),
			)
		})
	}
}