package proxmox

import (
	"bytes"
	"context"
	"errors"
	"fmt"

	"github.com/go-logr/logr"

	"gitea.home.hrajfrisbee.cz/kacerr/egress-proxies-operator/internal/provider"
	"gitea.home.hrajfrisbee.cz/kacerr/egress-proxies-operator/internal/provider/nocloud"
)

// seedISOName is the seed's file name on the ISO storage. Upload refuses a
// name without the .iso suffix (F12), and GC's blind spot is documented by
// this pattern (spec entry 11).
func seedISOName(name string) string {
	return name + "-seed.iso"
}

// seedVolID is the seed's volume id, as ide2 references it and as the
// storage content delete takes it.
func seedVolID(storage, name string) string {
	return storage + ":iso/" + seedISOName(name)
}

// buildSeed renders the NoCloud seed for req in memory (spec entry 5): a
// seed is tens of KiB. Nothing about its content is logged or put in an
// error. Only an empty name is Permanent; a staging failure (no /tmp, a
// full emptyDir) is left unclassified, so classify makes it Transient and
// the reconciler retries instead of latching the Proxy.
func (p *Provider) buildSeed(req provider.CreateRequest) (*bytes.Buffer, error) {
	vendorData, err := nocloud.BuildVendorData(p.cfg.VendorData, *p.cfg.InstallGuestAgent)
	if err != nil {
		return nil, fmt.Errorf("building vendor-data for %s: %w", req.Name, err)
	}
	var iso bytes.Buffer
	if err := nocloud.BuildSeedISO(req.Name, req.CloudInit, vendorData, &iso); err != nil {
		if errors.Is(err, nocloud.ErrEmptyName) {
			return nil, permanentf("building seed ISO: %v", err)
		}
		return nil, fmt.Errorf("building seed ISO for %s: %w", req.Name, err)
	}
	return &iso, nil
}

// uploadSeed puts a freshly built seed on the VM's node and waits for the
// copy (spec entry 5). An upload overwrites a file of the same name (F12),
// so what a cut-off attempt left is replaced without a delete first.
func (p *Provider) uploadSeed(ctx context.Context, log logr.Logger, node string, req provider.CreateRequest) error {
	iso, err := p.buildSeed(req)
	if err != nil {
		return err
	}
	volid := seedVolID(p.cfg.ISOStorage, req.Name)
	upid, err := p.api.UploadISO(ctx, node, p.cfg.ISOStorage, seedISOName(req.Name), iso, int64(iso.Len()))
	if err != nil {
		return fmt.Errorf("uploading seed %s: %w", volid, err)
	}
	if err := p.waitTask(ctx, log, upid, p.budgets.upload); err != nil {
		return fmt.Errorf("uploading seed %s: %w", volid, err)
	}
	return nil
}