package state

import (
	"fmt"

	"github.com/hashicorp/consul/agent/structs"
	"github.com/hashicorp/go-memdb"
)

const (
	caRootTableName = "connect-ca-roots"
)

// caRootTableSchema returns a new table schema used for storing
// CA roots for Connect.
func caRootTableSchema() *memdb.TableSchema {
	return &memdb.TableSchema{
		Name: caRootTableName,
		Indexes: map[string]*memdb.IndexSchema{
			"id": &memdb.IndexSchema{
				Name:         "id",
				AllowMissing: false,
				Unique:       true,
				Indexer: &memdb.UUIDFieldIndex{
					Field: "ID",
				},
			},
		},
	}
}

func init() {
	registerSchema(caRootTableSchema)
}

// CARoots returns the list of all CA roots.
func (s *Store) CARoots(ws memdb.WatchSet) (uint64, structs.CARoots, error) {
	tx := s.db.Txn(false)
	defer tx.Abort()

	// Get the index
	idx := maxIndexTxn(tx, caRootTableName)

	// Get all
	iter, err := tx.Get(caRootTableName, "id")
	if err != nil {
		return 0, nil, fmt.Errorf("failed CA root lookup: %s", err)
	}
	ws.Add(iter.WatchCh())

	var results structs.CARoots
	for v := iter.Next(); v != nil; v = iter.Next() {
		results = append(results, v.(*structs.CARoot))
	}
	return idx, results, nil
}

// CARootActive returns the currently active CARoot.
func (s *Store) CARootActive(ws memdb.WatchSet) (uint64, *structs.CARoot, error) {
	// Get all the roots since there should never be that many and just
	// do the filtering in this method.
	var result *structs.CARoot
	idx, roots, err := s.CARoots(ws)
	if err == nil {
		for _, r := range roots {
			if r.Active {
				result = r
				break
			}
		}
	}

	return idx, result, err
}

// CARootSetCAS sets the current CA root state using a check-and-set operation.
// On success, this will replace the previous set of CARoots completely with
// the given set of roots.
//
// The first boolean result returns whether the transaction succeeded or not.
func (s *Store) CARootSetCAS(idx, cidx uint64, rs []*structs.CARoot) (bool, error) {
	tx := s.db.Txn(true)
	defer tx.Abort()

	// Get the current max index
	if midx := maxIndexTxn(tx, caRootTableName); midx != cidx {
		return false, nil
	}

	// Go through and find any existing matching CAs so we can preserve and
	// update their Create/ModifyIndex values.
	for _, r := range rs {
		if r.ID == "" {
			return false, ErrMissingCARootID
		}

		existing, err := tx.First(caRootTableName, "id", r.ID)
		if err != nil {
			return false, fmt.Errorf("failed CA root lookup: %s", err)
		}

		if existing != nil {
			r.CreateIndex = existing.(*structs.CARoot).CreateIndex
		} else {
			r.CreateIndex = idx
		}
		r.ModifyIndex = idx
	}

	// Delete all
	_, err := tx.DeleteAll(caRootTableName, "id")
	if err != nil {
		return false, err
	}

	// Insert all
	for _, r := range rs {
		if err := tx.Insert(caRootTableName, r); err != nil {
			return false, err
		}
	}

	// Update the index
	if err := tx.Insert("index", &IndexEntry{caRootTableName, idx}); err != nil {
		return false, fmt.Errorf("failed updating index: %s", err)
	}

	tx.Commit()
	return true, nil
}