package router

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

	"go.jolheiser.com/vanity/cmd/flags"
	"go.jolheiser.com/vanity/database"
	"go.jolheiser.com/vanity/go-vanity"

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

func New(token string, db *database.Database) *chi.Mux {
	r := chi.NewRouter()
	r.Use(middleware.RedirectSlashes)
	r.Use(middleware.Recoverer)
	r.Use(middleware.Timeout(60 * time.Second))

	r.Get("/", indexGET(db))
	r.Options("/", infoPackages(db))
	r.Post("/", addUpdatePackage(db, token))
	r.Patch("/", addUpdatePackage(db, token))
	r.Delete("/", removePackage(db, token))
	r.Get("/*", vanityGET(db))

	return r
}

func indexGET(db *database.Database) http.HandlerFunc {
	return func(res http.ResponseWriter, req *http.Request) {
		packages, err := db.Packages()
		if err != nil {
			beaver.Errorf("could not load packages: %v", err)
			http.Error(res, "could not load packages", http.StatusInternalServerError)
			return
		}

		tpl, err := tmpl("index.tmpl")
		if err != nil {
			beaver.Warnf("could not load index template: %v", err)
		}

		if err := tpl.Execute(res, map[string]interface{}{
			"Packages": packages,
			"Index":    true,
		}); err != nil {
			beaver.Errorf("could not write response: %v", err)
		}
	}
}

func vanityGET(db *database.Database) http.HandlerFunc {
	return func(res http.ResponseWriter, req *http.Request) {
		key := chi.URLParam(req, "*")
		key = strings.Split(key, "/")[0]

		pkg, err := db.Package(key)
		if err != nil {
			if database.IsErrPackageNotFound(err) {
				http.NotFound(res, req)
				return
			}
			http.Error(res, "could not load package", http.StatusInternalServerError)
			return
		}

		sdf, err := vanity.AnalyzeSDF(pkg)
		if err != nil {
			beaver.Warnf("could not get SDF for %s: %v", key, err)
		}

		ctx := map[string]interface{}{
			"Package":  pkg,
			"Module":   pkg.Module(flags.Domain),
			"GoSource": fmt.Sprintf("%s %s %s %s", pkg.Module(flags.Domain), pkg.CloneHTTP, sdf.Dir, sdf.File),
			"Index":    false,
		}

		q := req.URL.Query()
		if q.Get("go-get") != "" || q.Get("git-import") != "" {
			tpl, err := tmpl("import.tmpl")
			if err != nil {
				beaver.Warnf("could not load import template: %v", err)
			}
			if err := tpl.Execute(res, ctx); err != nil {
				beaver.Errorf("could not write response: %v", err)
			}
			return
		}

		tpl, err := tmpl("vanity.tmpl")
		if err != nil {
			beaver.Warnf("could not load vanity template: %v", err)
		}
		if err := tpl.Execute(res, ctx); err != nil {
			beaver.Errorf("could not write response: %v", err)
		}
	}
}

func infoPackages(db *database.Database) func(http.ResponseWriter, *http.Request) {
	return func(res http.ResponseWriter, req *http.Request) {
		packages, err := db.Packages()
		if err != nil {
			http.Error(res, "could not load package", http.StatusInternalServerError)
			return
		}

		info := vanity.Info{
			Version:     Version,
			NumPackages: len(packages),
			Packages:    packages,
		}

		if err := json.NewEncoder(res).Encode(info); err != nil {
			http.Error(res, "could not marshal info", http.StatusInternalServerError)
		}
	}
}

func addUpdatePackage(db *database.Database, token string) func(http.ResponseWriter, *http.Request) {
	return func(res http.ResponseWriter, req *http.Request) {
		if req.Header.Get(vanity.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 vanity.Package
		if err := json.Unmarshal(data, &pkg); err != nil {
			res.WriteHeader(http.StatusBadRequest)
			return
		}

		exists, err := db.PackageJSON(pkg.Name)
		if err != nil && !database.IsErrPackageNotFound(err) {
			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(vanity.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 vanity.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)
	}
}