//! `koh migrate` — one-time conversion from Koh 2.

module cli

import json2
import os
import src.fmt
import src.machine
import src.migrate
import src.snapshot
import time

pub fn cmd_migrate(raw []string) int {
	args := parse('migrate', raw, Options{
		values: ['lane']
		flags:  ['json', 'yes']
	}) or { return usage_error(err.msg()) }
	mut lane := args.value('lane')
	if lane == '' {
		lane = migrate.default_lane
	}
	if lane !in ['dev', 'main'] {
		return usage_error('--lane takes dev or main, not "${lane}"')
	}
	plan := migrate.prepare(os.getwd(), lane) or { return refuse(args.json(), err.msg()) }
	if !args.json() {
		note('Koh 2 repo · lane ${plan.lane} · ${fmt.plural(plan.saves, 'save')} (${fmt.plural(plan.checkpoints, 'checkpoint')}) · ${fmt.plural(plan.objects, 'object')} · last save ${time.unix(plan.last_saved).ymmdd()}')
		note('this will:')
		note('  · copy the history into one .koh file and check every save')
		if plan.renames_build {
			note('  · rename kepr.build to koh.build, as its own save')
		}
		note('  · keep the Koh 2 data as ${migrate.archive_dir}/ — move it back to undo')
	}
	approved := confirm(args.flag('yes')) or { return refuse(args.json(), err.msg()) }
	if !approved {
		return refuse(args.json(), 'not migrating, then — nothing changed')
	}
	report := migrate.run(plan, fn (stage string, done int, total int) {
		working('${stage} ${done} / ${total} saves')
	}) or { return refuse(args.json(), err.msg()) }
	if args.json() {
		emit_json(json2.encode(MigrateJson{
			repo:         report.root
			lane:         report.lane
			saves:        report.saves
			checkpoints:  report.checkpoints
			flags:        report.flags
			objects:      report.objects
			head:         report.head
			ignore_moved: report.ignore_carried
			build_file:   report.build_renamed
			unsafe_paths: report.unsafe_paths
		}))
		return 0
	}
	ok('migrated ${fmt.plural(report.saves, 'save')} from Koh 2 (lane ${report.lane})')
	note('${fmt.plural(report.checkpoints, 'checkpoint')} · ${fmt.plural(report.flags, 'flag')} · ${fmt.plural(report.objects, 'object')}')
	warn_unsafe_paths(report.unsafe_paths)
	note('the Koh 2 data is untouched in ${migrate.archive_dir}/ — move it back to go back')
	if report.ignore_carried {
		note('carried the ignore rules to ${snapshot.ignore_file}')
	}
	if report.build_renamed {
		note('renamed kepr.build to koh.build, and saved that')
	}
	if report.log_md_was_tracked {
		warn('LOG.md was tracked by Koh 2; koh writes it itself now, so it is no longer snapshotted')
	}
	note('run "koh status" to see what the migration left, then "koh save"')
	if machine.has_remote() {
		note('this machine has a remote — run "koh offer" to publish the migrated history')
	}
	return 0
}

struct MigrateJson {
	repo         string
	lane         string
	saves        int
	checkpoints  int
	flags        int
	objects      int
	head         string
	ignore_moved bool
	build_file   bool
	unsafe_paths []string
}