package shares

import (
	"fmt"
	"strings"
)

// Header marks generated files so install scripts and humans can tell them apart.
const Header = "# Managed by nasmon — edits are overwritten. Change shares at http://<nas>:8090/shares"

func yesno(b bool) string {
	if b {
		return "yes"
	}
	return "no"
}

func anyGuest(c Config) bool {
	for _, s := range c.SMB.Shares {
		if s.Guest {
			return true
		}
	}
	return false
}

// RenderSMB produces the complete smb.conf. owner is the Unix account every
// SMB session acts as (force user), so files end up with the same owner the
// containers use. includes are drop-in files of other services appended as
// "include =" lines.
func RenderSMB(c Config, owner string, includes ...string) string {
	var b strings.Builder
	fmt.Fprintf(&b, "%s\n\n[global]\n", Header)
	// Bad User turns unknown accounts (e.g. the Windows login) into guests.
	// Without guest shares that only yields a guest session Windows refuses
	// with a misleading "network path not found" instead of a password prompt.
	mapGuest := "Never"
	if anyGuest(c) {
		mapGuest = "Bad User"
	}
	minProto := "server min protocol = SMB2"
	if c.SMB.Legacy {
		// old embedded clients (e.g. Supermicro BMC virtual media) only offer
		// SMB1 "NT LM 0.12" and authenticate with NTLMv1
		minProto = "server min protocol = NT1\n   ntlm auth = ntlmv1-permitted"
	}
	g := []string{
		"workgroup = " + c.SMB.Workgroup,
		"server string = " + c.SMB.ServerString,
		"server role = standalone server",
		"security = user",
		"map to guest = " + mapGuest,
		"guest account = nobody",
		minProto,
		"unix charset = UTF-8",
		"logging = file",
		"log file = /var/log/samba/log.%m",
		"max log size = 1000",
		"log level = 1",
		"load printers = no",
		"printing = bsd",
		"printcap name = /dev/null",
		"disable spoolss = yes",
		"ea support = yes",
		"vfs objects = fruit streams_xattr", // macOS clients: resource forks / Finder metadata as xattrs
		"fruit:metadata = stream",
		"fruit:model = MacSamba",
		"dos filemode = yes",
	}
	for _, l := range g {
		fmt.Fprintf(&b, "   %s\n", l)
	}
	for _, s := range c.SMB.Shares {
		fmt.Fprintf(&b, "\n[%s]\n", s.Name)
		lines := []string{
			"path = " + s.Path,
		}
		if s.Comment != "" {
			lines = append(lines, "comment = "+s.Comment)
		}
		lines = append(lines,
			"browseable = "+yesno(s.Browseable),
			"read only = "+yesno(s.ReadOnly),
			"guest ok = "+yesno(s.Guest),
		)
		if !s.Guest {
			lines = append(lines, "valid users = "+strings.Join(s.Users, " "))
		}
		lines = append(lines,
			"force user = "+owner,
			"force group = "+owner,
			"create mask = 0664",
			"directory mask = 0775",
		)
		if s.HideSysFiles {
			lines = append(lines, "veto files = /._*/.DS_Store/Thumbs.db/desktop.ini/", "delete veto files = yes")
		}
		for _, l := range lines {
			fmt.Fprintf(&b, "   %s\n", l)
		}
	}
	if len(includes) > 0 {
		b.WriteString("\n# Shares of other services (read-only in nasmon)\n")
		for _, f := range includes {
			fmt.Fprintf(&b, "include = %s\n", f)
		}
	}
	return b.String()
}

// RenderExports produces the exports(5) file. uid/gid are the ids squashed
// clients are mapped to.
func RenderExports(c Config, uid, gid string) string {
	var b strings.Builder
	fmt.Fprintf(&b, "%s\n", Header)
	for _, e := range c.NFS.Exports {
		opts := []string{"rw"}
		if e.ReadOnly {
			opts = []string{"ro"}
		}
		if e.Async {
			opts = append(opts, "async")
		} else {
			opts = append(opts, "sync")
		}
		switch e.Squash {
		case "all":
			opts = append(opts, "all_squash", "anonuid="+uid, "anongid="+gid)
		case "none":
			opts = append(opts, "no_root_squash")
		default:
			opts = append(opts, "root_squash", "anonuid="+uid, "anongid="+gid)
		}
		// crossmnt: child mounts (ZFS datasets or other filesystems) must be reachable
		opts = append(opts, "crossmnt", "no_subtree_check")
		var parts []string
		for _, cl := range e.Clients {
			parts = append(parts, cl+"("+strings.Join(opts, ",")+")")
		}
		fmt.Fprintf(&b, "%q %s\n", e.Path, strings.Join(parts, " "))
	}
	return b.String()
}