package cluster

import (
	"encoding/json"
	"fmt"
	"os"

	"gopkg.in/yaml.v3"
)

func (m *Cluster) init(opts *ScanOptions) error {
	for _, fn := range []func(*ScanOptions) error{
		m.initZones,
		m.scanZoneIDs,
		m.scanSort,
		m.scanGateways,
		m.initRegions,
	} {
		if err := fn(opts); err != nil {
			return err
		}
	}

	return nil
}

func (m *Cluster) initZones(opts *ScanOptions) error {
	var err error

	sub, err := DirFS(m.BaseDir)
	if err != nil {
		return err
	}

	m.dir = sub

	m.ForEachZone(func(z *Zone) bool {
		err = m.initZone(z, opts)
		return err != nil
	})

	return err
}

func (m *Cluster) initZone(z *Zone, _ *ScanOptions) error {
	var hasMissing bool
	var lastMachineID int

	z.zones = m
	z.logger = m

	z.ForEachMachine(func(p *Machine) bool {
		p.zone = z
		p.logger = z

		switch {
		case p.ID == 0:
			hasMissing = true
		case p.ID > lastMachineID:
			lastMachineID = z.ID
		}

		return false
	})

	if hasMissing {
		next := lastMachineID + 1

		z.ForEachMachine(func(p *Machine) bool {
			if p.ID == 0 {
				p.ID, next = next, next+1
			}

			return false
		})
	}

	z.ForEachMachine(func(p *Machine) bool {
		p.Name = fmt.Sprintf("%s-%v", z.Name, p.ID)
		return false
	})

	return nil
}

func decodeConfigData(data []byte) (out *Cluster, err error) {
	// try JSON first
	out = new(Cluster)
	err = json.Unmarshal(data, out)
	if err == nil {
		// good json
		return out, nil
	} else if _, ok := err.(*json.SyntaxError); !ok {
		// bad json
		return nil, err
	}

	out = new(Cluster)
	err = yaml.Unmarshal(data, out)
	if err != nil {
		// bad yaml too
		return nil, err
	}

	// good yaml
	return out, nil
}

// NewFromConfig loads the cluster data from the given file
func NewFromConfig(filename string, opts ...ScanOption) (*Cluster, error) {
	var scanOptions ScanOptions

	data, err := os.ReadFile(filename)
	if err != nil {
		return nil, err
	}

	m, err := decodeConfigData(data)
	if err != nil {
		return nil, err
	}

	for _, opt := range opts {
		if err = opt(m, &scanOptions); err != nil {
			return nil, err
		}
	}

	if err = m.setScanDefaults(&scanOptions); err != nil {
		return nil, err
	}

	if err := m.init(&scanOptions); err != nil {
		return nil, err
	}

	return m, nil
}