package provision

import (
	"context"

	"os"

	"github.com/carlosframework/platform/internal/release"
)

type RecordIndex struct {
	keys map[string][2]string
}

func IndexRecords(ctx context.Context, s release.Store) (*RecordIndex, error) {
	known, partial, err := knownAccounts(ctx, s)
	if err != nil {
		return nil, err
	}
	if partial {
		return nil, ErrRecordIndexRetry
	}
	keys, partial, err := listAppSubtree(ctx, s, known, "instances/")
	if err != nil {
		return nil, err
	}
	if partial {
		return nil, ErrRecordIndexRetry
	}
	out := &RecordIndex{keys: make(map[string][2]string)}
	for _, key := range keys {
		a, p, h, ok := ParseRecordKey(key, known)
		if !ok {
			continue
		}
		if _, duplicate := out.keys[h]; duplicate {
			out.keys[h] = [2]string{}
		} else {
			out.keys[h] = [2]string{a, p}
		}
	}
	return out, nil
}

type recordIndexRetry struct{}

func (recordIndexRetry) Error() string   { return os.ErrDeadlineExceeded.Error() }
func (recordIndexRetry) Temporary() bool { return true }

var ErrRecordIndexRetry error = recordIndexRetry{}

func (i *RecordIndex) Find(ctx context.Context, s release.Store, host string) (*Record, string, error) {
	names, ok := i.keys[host]
	if !ok {
		return nil, "", os.ErrNotExist
	}
	account, app := names[0], names[1]
	if account == "" {
		return nil, "", os.ErrPermission
	}
	rec, etag, err := GetRecordETag(ctx, s, account, app, host)
	if err != nil {
		return nil, "", err
	}
	if etag == "" || rec.Schema != 1 || !release.ValidAccount(account) || !release.ValidApp(app) {
		return nil, "", os.ErrPermission
	}
	if err := ValidateShape(*rec); err != nil {
		return nil, "", err
	}
	return rec, etag, nil
}

func FindRecordByHost(ctx context.Context, s release.Store, host string) (*Record, string, error) {
	index, err := IndexRecords(ctx, s)
	if err != nil {
		return nil, "", err
	}
	return index.Find(ctx, s, host)
}