#!/usr/bin/env ngs

# Running example: ./demo/ec2din.ngs
# Running example: NGS_table_Instances='["InstanceId", "PublicIpAddress", "PrivateIpAddress", "State", "KeyName", "SecurityGroups"]' ./demo/ec2din.ngs

ArgvMatcher('positionals', 'filters') do
doc filters - Show only instances matching the given filters. Possible filter forms are:
doc filters - vpc-xxxyyyzz - for specific vpc
doc filters - i-xxxyyyzz - for specific instance id
doc filters - 1.2.3.4 - for instance having given IP
doc filters - kkk=vvv - for instances having given tag value
F main(filters:Arr, allreg:Bool=false, j:Bool=false, c:Str=null, out_lines:Int=5, out_columns:Int=20, err_lines:Int=5, err_columns:Int=20) {

	c = Box(c).map(decode_json)

	if c {
		warn("ec2din.ngs: Using experimental 'c' switch. Behaviour subject to change.")
		config('table_Instances', %[InstanceId tag_Name tag_proj tag_env tag_role IPs State AZ ec out err])
	} else {
		config('table_Instances', %[InstanceId tag_Name tag_proj tag_env tag_role IPs InstanceType State KeyName SecurityGroups AZ RestOfTags])
	}

	table = Table('Instances')

	F limit_len(s:Str, l:Int) limit(s, l, '...')

	# region to az
	regions = {}

	local_filters = AllOf()

	filters = ['--filters'] +? collector filters.each(F(arg) {

		econd {

			arg == 'windows' collect("Name=platform,Values=windows")
			arg == 'linux' local_filters.push('Platform' not in X)

			arg.starts_with('vpc-') collect("Name=vpc-id,Values=$arg")

			arg.starts_with('i-') collect("Name=instance-id,Values=$arg")

			m = arg ~ /^([a-z]{2}-[a-z]+-[0-9]+)([a-z])?$/ {
				# region or az
				regions.dflt(m[0], {})
				if m.matches.len() == 3 {
					regions[m[0]][m[1]] = true
					throw InvalidArgument("Availability zones filtering is not supported yet")
				}
			}

			arg ~ /^[0-9.]+$/ {
				filter_name = if IPAddr(arg).is_private() then 'private-ip-address' else 'ip-address'
				collect("Name=$filter_name,Values=$arg")
			}

			arg ~ /^[a-z][0-9][.][0-9]*[a-z]+$/ collect("Name=instance-type,Values=$arg")

			arg in AWS::INSTANCE_STATES collect("Name=instance-state-name,Values=$arg")

			{kv = arg.split('='); kv.len() == 2} collect("Name=tag:${kv[0]},Values=${kv[1]}")
		}
	})

	len(regions) > 1 throws InvalidArgument("Multiple regions are not supported yet")

	instances = if allreg {
		# AZ is now important so moving it to be first
		config('table_Instances', ['AZ'] + config('table_Instances').without('AZ'))
		AWS::regions({ ``aws ec2 describe-instances --region $A $*filters`` })
	} else {
		reg = Argv({'--region': regions.keys()})
		``aws ec2 describe-instances $*filters $*reg``
	}
	instances .= sort('LaunchTime')

	instances .= filter(local_filters)

	c.each(F(cmd) {
		instances.pmap(F(i) {
			try {
				argv = cmd.map(only(Pfx('i.'), F(arg) {
					i[arg[2..null]]
				}))
				i.argv = argv
				p=$(ok: $*argv)
				i.ec = p.processes[-1].exit_code
				i.out = try p.stdout.lines().limit(out_lines).map(limit(X, out_columns))
				i.err = try p.stderr.lines().limit(err_lines).map(limit(X, err_columns))
			} catch(e:KeyNotFound) {
				guard e.container == i
				i.err = 'No ' + e.key
			}
		})
	})

	if j {
		echo(instances.encode_json())
		return
	}

	F tag_has_column(tag_name) ["full_tag_${tag_name}", "tag_${tag_name}"].any(X in table.cols_enum)

	instances % F(i) {
		if ENV.get('EC2DIN_SHOW_PROFILE', 'true').decode(Bool) {
			i.InstanceId = [i.InstanceId, i.get('IamInstanceProfile', {}).Box('Arn').map(basename).get('(no profile)')]
		}
		i.State = i.State.Name
		i.SecurityGroups = i.SecurityGroups.map(F(sg) "${limit_len(sg.GroupName, 15)}(${sg.GroupId})")
		i.AZ = i.Placement.AvailabilityZone
		# Tags here is a Hash (after straightening by stdlib)
		i.dflt('Tags', {})
		i.Name = i.Tags.get('Name', '-').limit_len(20)
		i.IPs = [try i.PublicIpAddress, try i.PrivateIpAddress]
		i.Tags.each(F(k, v) {
			i["full_tag_${k}"] = v
			i["tag_${k}"] = v.limit_len(20)
		})
		# TODO: Move layout management to Table, don't limit_len() here
		i.RestOfTags = i.Tags.rejectk(tag_has_column).map({ "${A.limit_len(10)}=${B.limit_len(15)}" })
	}
	table.push_all(instances)
	echo(table)
	log("Listed ${len(instances)} instances")
}