//! Command line entry: dispatch table, usage text and exit codes.
//!
//! Exit codes are fixed across every command: 0 success, 1 refusal or error,
//! 2 bad usage. Each command returns its code; nothing else calls `exit`.

module cli

import src.fmt

// Read from VERSION at build time, so the binary and the manifest cannot drift.
pub const version = $embed_file('../../VERSION').to_string().trim_space()

// The help screen. It is built rather than embedded in a constant, because the
// colour follows NO_COLOR, KOH_NO_COLOR and whether the output is a terminal.
// Flags are not shown here: `koh man <command>` documents every one.
pub fn usage_text() string {
	commands := [
		['save', 'snapshot your work'],
		['checkpoint', 'mark a place to come back to'],
		['status', 'where things stand'],
		['view', 'browse saves and checkpoints'],
		['diff', 'what changed'],
		['undo', 'step back'],
		['revert', 'throw away unsaved changes'],
		['load', 'go to any save'],
		['offer', 'send to your remote'],
		['steal', 'bring in from your remote'],
	]
	mut text := '${fmt.light('koh ${version} — version control for the solo developer')}\n'
	// A blank line between commands, so the eye lands on one line at a time, and
	// the list grows as commands land.
	for row in commands {
		text += '\n  ${fmt.gold(row[0])}${' '.repeat(12 - row[0].len)}${fmt.muted(row[1])}\n'
	}
	text += '\n  ${fmt.dim('also: remote · flag · pluck · peek · build · update')}\n'
	text += '        ${fmt.dim('init · doctor · ignore · strip · migrate')}\n'
	text += '\n  ${fmt.dim('koh man <command>  for options and examples')}\n'
	text += '\n  ${fmt.dim('Asha Software · asha.software')}\n'
	return text
}

pub fn run(argv []string) int {
	if argv.len < 2 {
		eprintln(usage_text())
		return 2
	}
	if needs_migration(argv) {
		return refuse('--json' in argv, 'this is a Koh 2 repo — run "koh migrate" first')
	}
	rest := argv[2..]
	match argv[1] {
		'--version', '-v' {
			println('koh ${version}')
			return 0
		}
		'--help', '-h' {
			println(usage_text())
			return 0
		}
		'init' {
			return cmd_init(rest)
		}
		'save' {
			return cmd_save(rest, false)
		}
		'checkpoint' {
			return cmd_save(rest, true)
		}
		'status' {
			return cmd_status(rest)
		}
		'view' {
			return cmd_view(rest)
		}
		'diff' {
			return cmd_diff(rest)
		}
		'undo' {
			return cmd_undo(rest)
		}
		'revert' {
			return cmd_revert(rest)
		}
		'load' {
			return cmd_load(rest)
		}
		'flag' {
			return cmd_flag(rest)
		}
		'pluck' {
			return cmd_pluck(rest)
		}
		'peek' {
			return cmd_peek(rest)
		}
		'doctor' {
			return cmd_doctor(rest)
		}
		'ignore' {
			return cmd_ignore(rest)
		}
		'strip' {
			return cmd_strip(rest)
		}
		'remote' {
			return cmd_remote(rest)
		}
		'offer' {
			return cmd_offer(rest)
		}
		'steal' {
			return cmd_steal(rest)
		}
		'build' {
			return cmd_build(rest)
		}
		'update' {
			return cmd_update(rest)
		}
		'migrate' {
			return cmd_migrate(rest)
		}
		'man', 'help' {
			return cmd_man(rest)
		}
		else {
			return usage_error('unknown command "${argv[1]}" — run "koh --help" for the command list')
		}
	}
}