package api

import (
	"crypto/rand"
	"encoding/base64"
	"net/http"

	"git.fabledsword.com/bvandeusen/minstrel/internal/apierror"
	"git.fabledsword.com/bvandeusen/minstrel/internal/audit"
	"git.fabledsword.com/bvandeusen/minstrel/internal/db/dbq"
)

// The Subsonic password is for clients that sign in with Subsonic's t/s
// scheme (md5 of the password plus a salt). Checking that needs the password
// itself, so it is stored readable (migration 0003). That is why Minstrel
// generates it rather than letting the user choose one: a generated value
// can never be a login password reused from somewhere else, so a leaked
// users table gives up access to this server's /rest API and nothing more
// (M462 #5026).

const subsonicPasswordBytes = 18 // 24 base64url characters

type subsonicPasswordStatusResp struct {
	Enabled bool `json:"enabled"`
}

type subsonicPasswordResp struct {
	Password string `json:"password"`
}

// handleGetMySubsonicPassword implements GET /api/me/subsonic-password. It
// reports only whether one is set; the value is shown once, when generated.
func (h *handlers) handleGetMySubsonicPassword(w http.ResponseWriter, r *http.Request) {
	user, ok := requireUser(w, r)
	if !ok {
		return
	}
	writeJSON(w, http.StatusOK, subsonicPasswordStatusResp{Enabled: user.SubsonicPassword != nil})
}

// handleGenerateMySubsonicPassword implements POST /api/me/subsonic-password:
// replaces any existing Subsonic password with a new random one and returns it.
func (h *handlers) handleGenerateMySubsonicPassword(w http.ResponseWriter, r *http.Request) {
	user, ok := requireUser(w, r)
	if !ok {
		return
	}
	b := make([]byte, subsonicPasswordBytes)
	if _, err := rand.Read(b); err != nil {
		h.logger.Error("generate subsonic password: rand failed", "err", err)
		writeErr(w, apierror.Internal(err))
		return
	}
	pw := base64.RawURLEncoding.EncodeToString(b)
	if err := dbq.New(h.pool).SetSubsonicPassword(r.Context(), dbq.SetSubsonicPasswordParams{
		ID:               user.ID,
		SubsonicPassword: &pw,
	}); err != nil {
		h.logger.Error("generate subsonic password: update failed", "err", err)
		writeErr(w, apierror.Internal(err))
		return
	}
	audit.WriteOrLog(r.Context(), h.pool, h.logger, user.ID, user.ID, audit.ActionSubsonicPasswordSet, nil)
	writeJSON(w, http.StatusOK, subsonicPasswordResp{Password: pw})
}

// handleClearMySubsonicPassword implements DELETE /api/me/subsonic-password,
// which turns t/s and p= sign-in off for the account.
func (h *handlers) handleClearMySubsonicPassword(w http.ResponseWriter, r *http.Request) {
	user, ok := requireUser(w, r)
	if !ok {
		return
	}
	if err := dbq.New(h.pool).SetSubsonicPassword(r.Context(), dbq.SetSubsonicPasswordParams{
		ID:               user.ID,
		SubsonicPassword: nil,
	}); err != nil {
		h.logger.Error("clear subsonic password: update failed", "err", err)
		writeErr(w, apierror.Internal(err))
		return
	}
	audit.WriteOrLog(r.Context(), h.pool, h.logger, user.ID, user.ID, audit.ActionSubsonicPasswordClear, nil)
	w.WriteHeader(http.StatusNoContent)
}