package host

import (
	"context"
	"os"
	"path/filepath"

	"github.com/carlosframework/platform/internal/hostbox"
	"github.com/carlosframework/platform/internal/hostguard"
	"github.com/carlosframework/platform/internal/layout"
	"github.com/carlosframework/platform/internal/provision"
	"github.com/carlosframework/platform/internal/release"
	"github.com/carlosframework/platform/internal/rootstate"
)

func (h ClaimRootHTTP) rootEmptyCensus() *hostbox.EmptyInstallationCensus {
	census := *h.Reconcile.Census
	census.OtherPath = h.rootSiblingPath
	return &census
}

func (h ClaimRootHTTP) rootSiblingPath(ctx context.Context, selected, root, rel string) (bool, error) {
	parent := filepath.ToSlash(filepath.Dir(rel))
	instance, instancePath := layout.InstanceCensusName(rel)
	if !(root == "data" && instancePath || root == "opt" && (parent == "live" || parent == "previous")) {
		return false, nil
	}
	payloads, err := h.Launches.GenerationPayloads(ctx)
	if err != nil {
		return false, err
	}
	for _, p := range payloads {
		in := p.Inventory
		if in.Host == selected {
			continue
		}
		candidate := root == "data" && (instance == provision.InstanceID(in.Host)) || root == "opt" && (rel == "live/"+in.Host || rel == "previous/"+in.Host)
		if !candidate {
			continue
		}
		own, err := h.Stop.Coordinator.Guard.Root.Installation(ctx, in.Host, hostguard.Captured{Incarnation: in.Incarnation, Stamp: in.InstallationStamp})
		if err != nil {
			return false, err
		}
		if own.Stamp != in.InstallationStamp {
			continue
		}
		if !in.Complete || own.Host != in.Host || own.Box != in.Box || own.Enrollment != in.Enrollment || own.InventoryRevision != p.Revision || own.Record != provision.RecordKey(own.Account, own.App, own.Host) {
			return false, os.ErrPermission
		}
		if root == "data" {
			for _, e := range in.Entries {
				if e.Kind == "path" && e.ManagedRoot == root && e.RelativePath == filepath.ToSlash(filepath.Join("instances", provision.InstanceID(in.Host))) && e.Materialization == "materialized" {
					err := generationPayloadFiles(ctx, h.Roots[root], []hostbox.GenerationPayload{{Inventory: hostbox.StopInventory{Entries: []hostbox.StopInventoryEntry{e}}}})
					if err == nil && rel != e.RelativePath {
						err = layout.VerifyInstanceCensusAlias(h.Roots[root], rel, in.Host)
					}
					return err == nil, err
				}
			}
			return false, nil
		}
		state, err := rootstate.Open(release.RootGenerationsDir, false, false)
		if err != nil {
			return false, err
		}
		pins, err := (&release.RootGenerations{Store: state}).Reservations(ctx)
		state.Close()
		if err != nil {
			return false, err
		}
		target, err := os.Readlink(filepath.Join(h.Roots[root], rel))
		if err != nil {
			return false, err
		}
		for _, pin := range pins {
			b := pin.Binding
			if b.Target.Host == own.Host && b.Target.Incarnation == own.Incarnation && b.Target.Box == own.Box && b.Target.Enrollment == own.Enrollment && b.Binding.Account == own.Account && b.Binding.App == own.App && b.Record == own.Record && target == b.Path && target == release.VersionPath(h.Roots[root], own.Account, b.Version, own.App) {
				return true, nil
			}
		}
		return false, os.ErrPermission
	}
	return false, nil
}