package router

import (
	"encoding/json"
	"io"
	"net/http"
	"time"

	"go.jolheiser.com/gpm/database"
	"go.jolheiser.com/gpm/go-gpm"

	"github.com/go-chi/chi"
	"github.com/go-chi/chi/middleware"
	"go.jolheiser.com/beaver"
)

var Version = "develop"

func New(token string, db *database.Database) *chi.Mux {
	r := chi.NewRouter()
	r.Use(middleware.RedirectSlashes)
	r.Use(middleware.Recoverer)
	r.Use(middleware.Timeout(30 * time.Second))

	r.Get("/", handleHome(db))
	r.Post("/", addUpdatePackage(db, token))
	r.Patch("/", addUpdatePackage(db, token))
	r.Delete("/", removePackage(db, token))
	r.Get("/{name}", getPackage(db))

	return r
}

func handleHome(db *database.Database) func(res http.ResponseWriter, _ *http.Request) {
	return func(res http.ResponseWriter, _ *http.Request) {
		pkgs, err := db.Packages()
		if err != nil {
			beaver.Error(err)
			return
		}

		status, err := json.Marshal(gpm.Info{
			Version:     Version,
			NumPackages: len(pkgs),
			Packages:    pkgs,
		})
		if err != nil {
			res.WriteHeader(http.StatusInternalServerError)
			_, _ = res.Write([]byte("{}"))
			return
		}

		_, _ = res.Write(status)
	}
}

func getPackage(db *database.Database) func(http.ResponseWriter, *http.Request) {
	return func(res http.ResponseWriter, req *http.Request) {
		name := chi.URLParam(req, "name")

		pkg, err := db.PackageJSON(name)
		if err != nil {
			res.WriteHeader(http.StatusNotFound)
			_, _ = res.Write([]byte("{}"))
			return
		}

		_, _ = res.Write(pkg)
	}
}

func addUpdatePackage(db *database.Database, token string) func(http.ResponseWriter, *http.Request) {
	return func(res http.ResponseWriter, req *http.Request) {
		if req.Header.Get(gpm.TokenHeader) != token {
			res.WriteHeader(http.StatusUnauthorized)
			return
		}

		data, err := io.ReadAll(req.Body)
		if err != nil {
			res.WriteHeader(http.StatusBadRequest)
			return
		}
		defer req.Body.Close()

		var pkg gpm.Package
		if err := json.Unmarshal(data, &pkg); err != nil {
			res.WriteHeader(http.StatusBadRequest)
			return
		}

		exists, err := db.PackageJSON(pkg.Name)
		if err != nil {
			res.WriteHeader(http.StatusInternalServerError)
			return
		}
		switch req.Method {
		case http.MethodPost:
			if exists != nil {
				res.WriteHeader(http.StatusConflict)
				return
			}
		case http.MethodPatch:
			if exists == nil {
				res.WriteHeader(http.StatusNotFound)
				return
			}
		}

		if err := db.PutPackage(pkg); err != nil {
			res.WriteHeader(http.StatusInternalServerError)
			return
		}

		switch req.Method {
		case http.MethodPost:
			res.WriteHeader(http.StatusCreated)
		case http.MethodPatch:
			res.WriteHeader(http.StatusOK)
		}
	}
}

func removePackage(db *database.Database, token string) func(http.ResponseWriter, *http.Request) {
	return func(res http.ResponseWriter, req *http.Request) {
		if req.Header.Get(gpm.TokenHeader) != token {
			res.WriteHeader(http.StatusUnauthorized)
			return
		}

		data, err := io.ReadAll(req.Body)
		if err != nil {
			res.WriteHeader(http.StatusBadRequest)
			return
		}
		defer req.Body.Close()

		var pkg gpm.Package
		if err := json.Unmarshal(data, &pkg); err != nil {
			res.WriteHeader(http.StatusBadRequest)
			return
		}

		if err := db.RemovePackage(pkg.Name); err != nil {
			res.WriteHeader(http.StatusInternalServerError)
			return
		}

		res.WriteHeader(http.StatusOK)
	}
}