package website

import (
	"fmt"
	"net/http"
	"slices"
	"strings"

	"gitlab.com/tozd/go/errors"
	"go.alanpearce.eu/website/internal/builder"
	"go.alanpearce.eu/website/internal/config"
	ihttp "go.alanpearce.eu/website/internal/http"
	"go.alanpearce.eu/website/internal/server"
	"go.alanpearce.eu/website/internal/storage"
	"go.alanpearce.eu/website/internal/storage/sqlite"
	"go.alanpearce.eu/website/internal/update"
	"go.alanpearce.eu/website/internal/vcs"
	"go.alanpearce.eu/website/templates"
	"go.alanpearce.eu/x/log"

	"github.com/benpate/digit"
)

type Website struct {
	config       *config.Config
	log          *log.Logger
	reader       storage.Reader
	me           digit.Resource
	acctResource string
	*server.App
}

func New(
	opts *Options,
	log *log.Logger,
) (*Website, error) {
	website := &Website{
		log: log,
		App: &server.App{
			Shutdown: func() {},
		},
	}
	builderOptions := &builder.Options{
		Source:      opts.Source,
		Development: opts.Development,
	}

	repo, exists, err := vcs.CloneOrOpen(&vcs.Options{
		LocalPath: opts.Source,
		RemoteURL: opts.VCS.RemoteURL,
		Branch:    opts.VCS.Branch,
	}, log.Named("vcs"))
	if err != nil {
		return nil, errors.WithMessage(err, "could not open repository")
	}
	builderOptions.Repo = repo

	if exists && !opts.Development {
		_, err := repo.Update("")
		if err != nil {
			return nil, errors.WithMessage(err, "could not update repository")
		}
	}

	log.Debug("getting config from source", "source", opts.Source)
	cfg, err := config.GetConfig(opts.Source, log)
	if err != nil {
		return nil, errors.WithMessage(err, "could not load configuration")
	}

	mux := ihttp.NewServeMux()
	mux.HandleError(func(err *ihttp.Error, w http.ResponseWriter, r *http.Request) {
		if strings.Contains(r.Header.Get("Accept"), "text/html") {
			w.WriteHeader(err.Code)
			err := templates.Error(cfg, r.URL.Path, err).Render(r.Context(), w)
			if err != nil {
				http.Error(w, err.Error(), http.StatusInternalServerError)
			}
		} else {
			http.Error(w, err.Message, err.Code)
		}
	})

	if opts.Development {
		opts.DBPath = ":memory:"

		cfg.CSP.ScriptSrc = slices.Insert(cfg.CSP.ScriptSrc, 0, "'unsafe-inline'")
		cfg.CSP.ConnectSrc = slices.Insert(cfg.CSP.ConnectSrc, 0, "'self'")

		cfg.BaseURL = opts.BaseURL
	}

	db, err := sqlite.OpenDB(opts.DBPath)
	if err != nil {
		return nil, errors.WithMessage(err, "could not open database")
	}

	builderOptions.Storage, err = sqlite.NewWriter(db, log.Named("storage"), &sqlite.Options{
		Compress: true,
	})
	if err != nil {
		return nil, errors.WithMessage(err, "could not create storage writer")
	}

	website.Domain = cfg.BaseURL.Hostname()

	err = rebuild(builderOptions, cfg, log)
	if err != nil {
		return nil, errors.WithMessage(err, "could not build site")
	}

	if opts.Development {
		fw, err := update.NewFileWatcher(
			log.Named("watcher"),
			opts.Source,
			"templates",
		)
		if err != nil {
			return nil, errors.WithMessage(err, "could not create file listener")
		}

		go func(events chan update.Event, errs chan error) {
			err := fw.Wait(events, errs)
			if err != nil {
				log.Panic("could not start update listener", "error", err)
			}
			for event := range events {
				filename := event.FileEvents[0].Name
				log.Info("rebuilding site", "changed_file", filename)
				db.Close()
				db, err = sqlite.OpenDB(opts.DBPath)
				if err != nil {
					log.Error("error opening database", "error", err)
				}
				website.reader, err = sqlite.NewReader(db, log.Named("reader"))
				if err != nil {
					log.Error("error creating sqlite reader", "error", err)
				}
				builderOptions.Storage, err = sqlite.NewWriter(
					db,
					log.Named("storage"),
					&sqlite.Options{},
				)
				if err != nil {
					log.Error("error creating sqlite writer", "error", err)
				}

				err := rebuild(builderOptions, cfg, log)
				if err != nil {
					log.Error("error rebuilding site", "error", err)
				}
				opts.LiveReload.Reload()
			}
		}(make(chan update.Event, 1), make(chan error, 1))
	}

	website.reader, err = sqlite.NewReader(db, log.Named("reader"))
	if err != nil {
		return nil, errors.WithMessage(err, "error creating sqlite reader")
	}

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

	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.config = cfg
	website.App.Handler = mux

	return website, nil
}

func updateCSPHashes(config *config.Config, r *builder.Result) {
	for i, h := range r.Hashes {
		config.CSP.StyleSrc[i] = fmt.Sprintf("'%s'", h)
	}
}

func rebuild(builderConfig *builder.Options, config *config.Config, log *log.Logger) error {
	r, err := builder.BuildSite(builderConfig, config, log.Named("builder"))
	if err != nil {
		return errors.WithMessage(err, "could not build site")
	}
	updateCSPHashes(config, r)

	return nil
}