package store

import (
	"context"
	"errors"

	"github.com/tech/sendico/ledger/storage"
	"github.com/tech/sendico/ledger/storage/model"
	"github.com/tech/sendico/pkg/db/repository"
	ri "github.com/tech/sendico/pkg/db/repository/index"
	"github.com/tech/sendico/pkg/merrors"
	"github.com/tech/sendico/pkg/mlogger"
	"go.mongodb.org/mongo-driver/bson/primitive"
	"go.mongodb.org/mongo-driver/mongo"
	"go.uber.org/zap"
)

type accountsStore struct {
	logger mlogger.Logger
	repo   repository.Repository
}

func NewAccounts(logger mlogger.Logger, db *mongo.Database) (storage.AccountsStore, error) {
	repo := repository.CreateMongoRepository(db, model.AccountsCollection)

	// Create compound index on organizationRef + accountCode + currency (unique)
	uniqueIndex := &ri.Definition{
		Keys: []ri.Key{
			{Field: "organizationRef", Sort: ri.Asc},
			{Field: "accountCode", Sort: ri.Asc},
			{Field: "currency", Sort: ri.Asc},
		},
		Unique: true,
	}
	if err := repo.CreateIndex(uniqueIndex); err != nil {
		logger.Error("failed to ensure accounts unique index", zap.Error(err))
		return nil, err
	}

	// Create index on organizationRef for listing
	orgIndex := &ri.Definition{
		Keys: []ri.Key{
			{Field: "organizationRef", Sort: ri.Asc},
		},
	}
	if err := repo.CreateIndex(orgIndex); err != nil {
		logger.Error("failed to ensure accounts organization index", zap.Error(err))
		return nil, err
	}

	childLogger := logger.Named(model.AccountsCollection)
	childLogger.Debug("accounts store initialised", zap.String("collection", model.AccountsCollection))

	return &accountsStore{
		logger: childLogger,
		repo:   repo,
	}, nil
}

func (a *accountsStore) Create(ctx context.Context, account *model.Account) error {
	if account == nil {
		a.logger.Warn("attempt to create nil account")
		return merrors.InvalidArgument("accountsStore: nil account")
	}

	if err := a.repo.Insert(ctx, account, nil); err != nil {
		if mongo.IsDuplicateKeyError(err) {
			a.logger.Warn("duplicate account code", zap.String("accountCode", account.AccountCode),
				zap.String("currency", account.Currency))
			return merrors.DataConflict("account with this code and currency already exists")
		}
		a.logger.Warn("failed to create account", zap.Error(err))
		return err
	}

	a.logger.Debug("account created", zap.String("accountCode", account.AccountCode),
		zap.String("currency", account.Currency))
	return nil
}

func (a *accountsStore) Get(ctx context.Context, accountRef primitive.ObjectID) (*model.Account, error) {
	if accountRef.IsZero() {
		a.logger.Warn("attempt to get account with zero ID")
		return nil, merrors.InvalidArgument("accountsStore: zero account ID")
	}

	result := &model.Account{}
	if err := a.repo.Get(ctx, accountRef, result); err != nil {
		if errors.Is(err, merrors.ErrNoData) {
			a.logger.Debug("account not found", zap.String("accountRef", accountRef.Hex()))
			return nil, storage.ErrAccountNotFound
		}
		a.logger.Warn("failed to get account", zap.Error(err), zap.String("accountRef", accountRef.Hex()))
		return nil, err
	}

	a.logger.Debug("account loaded", zap.String("accountRef", accountRef.Hex()),
		zap.String("accountCode", result.AccountCode))
	return result, nil
}

func (a *accountsStore) GetByAccountCode(ctx context.Context, orgRef primitive.ObjectID, accountCode, currency string) (*model.Account, error) {
	if orgRef.IsZero() {
		a.logger.Warn("attempt to get account with zero organization ID")
		return nil, merrors.InvalidArgument("accountsStore: zero organization ID")
	}
	if accountCode == "" {
		a.logger.Warn("attempt to get account with empty code")
		return nil, merrors.InvalidArgument("accountsStore: empty account code")
	}
	if currency == "" {
		a.logger.Warn("attempt to get account with empty currency")
		return nil, merrors.InvalidArgument("accountsStore: empty currency")
	}

	query := repository.Query().
		Filter(repository.Field("organizationRef"), orgRef).
		Filter(repository.Field("accountCode"), accountCode).
		Filter(repository.Field("currency"), currency)

	result := &model.Account{}
	if err := a.repo.FindOneByFilter(ctx, query, result); err != nil {
		if errors.Is(err, merrors.ErrNoData) {
			a.logger.Debug("account not found by code", zap.String("accountCode", accountCode),
				zap.String("currency", currency))
			return nil, storage.ErrAccountNotFound
		}
		a.logger.Warn("failed to get account by code", zap.Error(err), zap.String("accountCode", accountCode))
		return nil, err
	}

	a.logger.Debug("account loaded by code", zap.String("accountCode", accountCode),
		zap.String("currency", currency))
	return result, nil
}

func (a *accountsStore) GetDefaultSettlement(ctx context.Context, orgRef primitive.ObjectID, currency string) (*model.Account, error) {
	if orgRef.IsZero() {
		a.logger.Warn("attempt to get default settlement with zero organization ID")
		return nil, merrors.InvalidArgument("accountsStore: zero organization ID")
	}
	if currency == "" {
		a.logger.Warn("attempt to get default settlement with empty currency")
		return nil, merrors.InvalidArgument("accountsStore: empty currency")
	}

	limit := int64(1)
	query := repository.Query().
		Filter(repository.Field("organizationRef"), orgRef).
		Filter(repository.Field("currency"), currency).
		Filter(repository.Field("isSettlement"), true).
		Limit(&limit)

	result := &model.Account{}
	if err := a.repo.FindOneByFilter(ctx, query, result); err != nil {
		if errors.Is(err, merrors.ErrNoData) {
			a.logger.Debug("default settlement account not found",
				zap.String("currency", currency),
				zap.String("organizationRef", orgRef.Hex()))
			return nil, storage.ErrAccountNotFound
		}
		a.logger.Warn("failed to get default settlement account", zap.Error(err),
			zap.String("organizationRef", orgRef.Hex()),
			zap.String("currency", currency))
		return nil, err
	}

	a.logger.Debug("default settlement account loaded",
		zap.String("accountRef", result.GetID().Hex()),
		zap.String("currency", currency))
	return result, nil
}

func (a *accountsStore) ListByOrganization(ctx context.Context, orgRef primitive.ObjectID, limit int, offset int) ([]*model.Account, error) {
	if orgRef.IsZero() {
		a.logger.Warn("attempt to list accounts with zero organization ID")
		return nil, merrors.InvalidArgument("accountsStore: zero organization ID")
	}

	limit64 := int64(limit)
	offset64 := int64(offset)
	query := repository.Query().
		Filter(repository.Field("organizationRef"), orgRef).
		Limit(&limit64).
		Offset(&offset64)

	accounts := make([]*model.Account, 0)
	err := a.repo.FindManyByFilter(ctx, query, func(cur *mongo.Cursor) error {
		doc := &model.Account{}
		if err := cur.Decode(doc); err != nil {
			return err
		}
		accounts = append(accounts, doc)
		return nil
	})
	if err != nil {
		a.logger.Warn("failed to list accounts", zap.Error(err))
		return nil, err
	}

	a.logger.Debug("listed accounts", zap.Int("count", len(accounts)))
	return accounts, nil
}

func (a *accountsStore) UpdateStatus(ctx context.Context, accountRef primitive.ObjectID, status model.AccountStatus) error {
	if accountRef.IsZero() {
		a.logger.Warn("attempt to update account status with zero ID")
		return merrors.InvalidArgument("accountsStore: zero account ID")
	}

	patch := repository.Patch().Set(repository.Field("status"), status)
	if err := a.repo.Patch(ctx, accountRef, patch); err != nil {
		a.logger.Warn("failed to update account status", zap.Error(err), zap.String("accountRef", accountRef.Hex()))
		return err
	}

	a.logger.Debug("account status updated", zap.String("accountRef", accountRef.Hex()),
		zap.String("status", string(status)))
	return nil
}