package website

import (
	"os"
	"path/filepath"
	"slices"
	"sync"

	"gitlab.com/tozd/go/errors"
	"go.alanpearce.eu/homestead/internal/config"
	"go.alanpearce.eu/homestead/internal/events"
	"go.alanpearce.eu/homestead/internal/fetcher"
	"go.alanpearce.eu/homestead/internal/file"
	ihttp "go.alanpearce.eu/homestead/internal/http"
	"go.alanpearce.eu/homestead/internal/server"
	"go.alanpearce.eu/homestead/internal/stats"
	"go.alanpearce.eu/homestead/internal/stats/goatcounter"
	"go.alanpearce.eu/homestead/internal/stats/nullcounter"
	"go.alanpearce.eu/homestead/internal/storage"
	"go.alanpearce.eu/homestead/internal/storage/sqlite"
	"go.alanpearce.eu/homestead/templates"
	"go.alanpearce.eu/x/log"

	"github.com/benpate/digit"
	"github.com/osdevisnot/sorvor/pkg/livereload"
)

type Options struct {
	Root             string     `conf:"default:./website"`
	Redirect         bool       `conf:"default:true"`
	Development      bool       `conf:"default:false,flag:dev"`
	FetchURL         config.URL `conf:"default:https://ci.alanpearce.eu/archive/website/"`
	BaseURL          config.URL
	GoatcounterToken string

	Redis      *events.RedisOptions
	LiveReload *livereload.LiveReload `conf:"-"`
}

type Website struct {
	config       *config.Config
	siteSettings *templates.SiteSettings
	counter      stats.Counter
	log          *log.Logger
	reader       storage.Reader
	me           digit.Resource
	acctResource string
	*server.App
}

func New(
	opts *Options,
	log *log.Logger,
) (*Website, errors.E) {
	website := &Website{
		log: log,
		App: &server.App{
			Shutdown: func() {},
		},
	}

	err := prepareRootDirectory(opts.Root)
	if err != nil {
		return nil, errors.WithMessage(err, "could not prepare root directory")
	}

	var listener events.Listener
	if opts.Redis.Address != "" {
		log.Debug("using redis listener")
		listener, err = events.NewRedisListener(opts.Redis, log.Named("redis"))
	} else {
		log.Debug("using file watcher")
		listener, err = events.NewFileWatcher(log.Named("events"), "website")
	}
	if err != nil {
		return nil, errors.WithMessage(err, "could not create update listener")
	}

	var cfg *config.Config
	fetcher := fetcher.New(log.Named("fetcher"), &fetcher.Options{
		FetchURL:     opts.FetchURL,
		RedisEnabled: opts.Redis.Address != "",
		Root:         opts.Root,
		Listener:     listener,
	})
	roots, err := fetcher.Subscribe()
	if err != nil {
		return nil, errors.WithMessage(err, "could not set up fetcher")
	}

	firstUpdate := make(chan bool)
	go func() {
		updated := sync.OnceFunc(func() {
			firstUpdate <- true
			close(firstUpdate)
		})
		for root := range roots {
			log.Debug("getting config from source", "source", root)
			cfg, err = config.GetConfig(root, log)
			if err != nil {
				log.Panic("could not load configuration", "error", err)
			}
			website.config = cfg
			website.siteSettings = &templates.SiteSettings{
				Title:            cfg.Title,
				Language:         cfg.Language,
				Menu:             cfg.Menu,
				InjectLiveReload: opts.Development,
			}

			if opts.Development {
				cfg.CSP.ScriptSrc = slices.Insert(cfg.CSP.ScriptSrc, 0, "'unsafe-inline'")
				cfg.CSP.ConnectSrc = slices.Insert(cfg.CSP.ConnectSrc, 0, "'self'")
			}
			if opts.GoatcounterToken == "" {
				if !opts.Development {
					log.Warn("in production without a goatcounter token")
				}
				website.counter = nullcounter.New(&nullcounter.Options{
					Logger: log.Named("counter"),
				})
			} else {
				website.counter = goatcounter.New(&goatcounter.Options{
					Logger: log.Named("counter"),
					URL:    &cfg.GoatCounter,
					Token:  opts.GoatcounterToken,
				})
			}

			if opts.BaseURL.URL != nil && opts.BaseURL.Hostname() != "" {
				cfg.BaseURL = opts.BaseURL
			}

			website.Domain = cfg.BaseURL.Hostname()

			siteDB := filepath.Join(root, "site.db")
			db, err := sqlite.OpenDB(siteDB)
			if err != nil {
				log.Panic("could not open database", "error", err)
			}

			website.reader, err = sqlite.NewReader(db, log.Named("reader"))
			if err != nil {
				log.Panic("could not create database reader", "error", err)
			}

			updated()
		}
	}()

	<-firstUpdate

	website.acctResource = "acct:" + cfg.Email
	website.me = digit.NewResource(website.acctResource).
		Link("http://openid.net/specs/connect/1.0/issuer", "", cfg.OIDCHost.String())

	mux := ihttp.NewServeMux()
	mux.HandleError(website.ErrorHandler)
	mux.Handle("/", website)
	mux.HandleFunc("/.well-known/webfinger", website.webfinger)
	const oidcPath = "/.well-known/openid-configuration"
	mux.ServeMux.Handle(oidcPath, ihttp.RedirectHandler(cfg.OIDCHost.JoinPath(oidcPath), 302))

	website.App.Handler = mux

	return website, nil
}

func prepareRootDirectory(root string) errors.E {
	if !file.Exists(root) {
		err := os.MkdirAll(root, 0755)
		if err != nil {
			return errors.WithMessage(err, "could not create root directory")
		}
	}

	return nil
}