/*
goredo -- djb's redo implementation on pure Go
Copyright (C) 2020-2021 Sergey Matveev <stargrave@stargrave.org>

This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, version 3 of the License.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

package main

import (
	"flag"
	"fmt"
	"os"
)

const (
	Version  = "1.19.0"
	Warranty = `Copyright (C) 2020-2021 Sergey Matveev

This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, version 3 of the License.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program.  If not, see <http://www.gnu.org/licenses/>.`
)

func usage(cmd string) {
	var d string
	switch cmd {
	case CmdNameRedo:
		d = `Usage: redo [-j X] [-k] [-s] [-x|-xx] [options] [target ...]

Forcefully and *sequentially* build specified targets.
If no targets specified, then use "all" one.`
	case CmdNameRedoIfchange:
		d = `Usage: redo-ifchange [-j X] [-k] [-s] [-x|-xx] target [...]

Build specified targets in parallel, if they are changed.
Record them as dependencies for current target.`
	case CmdNameRedoIfcreate:
		d = `Usage: redo-ifcreate target [...]

Record ifcreate dependency for current target. Unusable outside .do.`
	case CmdNameRedoAlways:
		d = `Usage: redo-always

Always build current target. Unusable outside .do.`
	case CmdNameRedoCleanup:
		d = `Usage: redo-cleanup [-n] {full,log,tmp} [...]

Remove either all goredo's related temporary files, or kept stderr
logs, or everything (including .redo directories) related.`
	case CmdNameRedoLog:
		d = `Usage: redo-log [-c] [-r] target [ | tai64nlocal ]

Display kept target's stderr with TAI64N timestamped lines. Only the
last build is kept. You must enable stderr keeping with either -logs,
or REDO_LOGS=1. -c option show the exact command invoked, start and
finish time. -r option recursively and linearly show also all deeper
redo calls and their logs.`
	case CmdNameRedoDot:
		d = `Usage: redo-dot target [...]

Write dependency DOT graph to stdout.`
	case CmdNameRedoStamp:
		d = `Usage: redo-stamp < [$3]

Record stamp dependency for current target. Unusable outside .do.
Stamp dependency does not play any role, as all targets are hashed
anyway.`
	case CmdNameRedoWhichdo:
		d = `Usage: redo-whichdo target

Display .do search paths for specified target. Exits successfully
if the last .do in output if the found existing one.`
	case CmdNameRedoTargets:
		d = `Usage: redo-targets [target ...]

List all currently known targets.`
	case CmdNameRedoSources:
		d = `Usage: redo-sources [target ...]

List all currently known source files.`
	case CmdNameRedoOOD:
		d = `Usage: redo-ood [target ...]

List all currently known out-of-date targets.`
	case CmdNameRedoAffects:
		d = `Usage: redo-affects target [...]

List all targets that will be affected by changing the specified ones.`
	default:
		d = `Usage: goredo -symlinks

goredo expects to be called through the symbolic link to it.
Available commands: redo, redo-affects, redo-always, redo-cleanup,
redo-dot, redo-ifchange, redo-ifcreate, redo-log, redo-ood,
redo-sources, redo-stamp, redo-targets, redo-whichdo.`
	}
	fmt.Fprintf(os.Stderr, "%s\n\nCommon options:\n", d)
	flag.PrintDefaults()
	fmt.Fprintln(os.Stderr, `
Additional environment variables:
  NO_COLOR -- disable messages colouring
  REDO_TOP_DIR -- do not search for .do above that directory
                  (it can contain .redo/top as an alternative)`)
	if cmd == CmdNameRedo || cmd == CmdNameRedoIfchange {
		fmt.Fprintln(os.Stderr, `
  REDO_NO_SYNC -- disable files/directories explicit filesystem syncing
  REDO_INODE_NO_TRUST -- do not trust inode information (except for size)
                         and always check file's hash
  REDO_MAKE -- bmake/gmake/none(default) jobserver protocol compatibility`)
	}
}