package storages

import (
	"context"
	"database/sql"
	"errors"

	"backend/database/fields"
	"backend/database/schemas/public/model"
	"backend/database/schemas/public/table"
	"backend/providers/otel"

	. "github.com/go-jet/jet/v2/postgres"
	"github.com/samber/lo"
	log "github.com/sirupsen/logrus"
	"github.com/spf13/afero"
	semconv "go.opentelemetry.io/otel/semconv/v1.4.0"
)

// @provider:except
type Service struct {
	db  *sql.DB
	log *log.Entry `inject:"false"`
}

func (svc *Service) Prepare() error {
	svc.log = log.WithField("module", "storages.service")
	_ = Int(1)
	return nil
}

// GetStorages
func (svc *Service) GetStorages(ctx context.Context) ([]model.Storages, error) {
	_, span := otel.Start(ctx, "storages.service.GetStorages")
	defer span.End()

	tbl := table.Storages
	stmt := tbl.SELECT(tbl.AllColumns)
	span.SetAttributes(semconv.DBStatementKey.String(stmt.DebugSql()))

	var storages []model.Storages
	if err := stmt.QueryContext(ctx, svc.db, &storages); err != nil {
		return nil, err
	}
	return storages, nil
}

// GetStorageByID
func (svc *Service) GetStorageByID(ctx context.Context, id int64) (*model.Storages, error) {
	_, span := otel.Start(ctx, "storages.service.GetStorageByID")
	defer span.End()

	tbl := table.Storages
	stmt := tbl.SELECT(tbl.AllColumns).WHERE(tbl.ID.EQ(Int64(id)))
	span.SetAttributes(semconv.DBStatementKey.String(stmt.DebugSql()))

	var storage model.Storages
	if err := stmt.QueryContext(ctx, svc.db, &storage); err != nil {
		return nil, err
	}
	return &storage, nil
}

// DeleteStorageByID
func (svc *Service) DeleteStorageByID(ctx context.Context, id int64) error {
	_, span := otel.Start(ctx, "storages.service.DeleteStorageByID")
	defer span.End()

	tbl := table.Storages
	stmt := tbl.DELETE().WHERE(tbl.ID.EQ(Int64(id)))
	span.SetAttributes(semconv.DBStatementKey.String(stmt.DebugSql()))

	_, err := stmt.ExecContext(ctx, svc.db)
	return err
}

// Create
func (svc *Service) Create(ctx context.Context, req *model.Storages) error {
	_, span := otel.Start(ctx, "storages.service.Create")
	defer span.End()

	tbl := table.Storages
	stmt := tbl.INSERT(tbl.Name, tbl.Type, tbl.Config).VALUES(req.Name, req.Type, req.Config)
	span.SetAttributes(semconv.DBStatementKey.String(stmt.DebugSql()))

	_, err := stmt.ExecContext(ctx, svc.db)
	return err
}

// SetDefault
func (svc *Service) SetDefault(ctx context.Context, id int64) error {
	_, span := otel.Start(ctx, "storages.service.SetDefault")
	defer span.End()

	// Start transaction
	tx, err := svc.db.BeginTx(ctx, nil)
	if err != nil {
		return err
	}
	defer tx.Rollback()

	tbl := table.Storages

	// First, set all storages' is_default to false
	resetStmt := tbl.
		UPDATE(tbl.IsDefault).
		SET(tbl.IsDefault.SET(Bool(false)))

	span.SetAttributes(semconv.DBStatementKey.String(resetStmt.DebugSql()))
	if _, err := resetStmt.ExecContext(ctx, tx); err != nil {
		return err
	}

	// Then, set the specified storage's is_default to true
	setDefaultStmt := tbl.
		UPDATE(tbl.IsDefault).
		SET(tbl.IsDefault.SET(Bool(true))).
		WHERE(tbl.ID.EQ(Int64(id)))

	span.SetAttributes(semconv.DBStatementKey.String(setDefaultStmt.DebugSql()))

	if _, err := setDefaultStmt.ExecContext(ctx, tx); err != nil {
		return err
	}

	// Commit transaction
	return tx.Commit()
}

// GetDefault
func (svc *Service) GetDefault(ctx context.Context) (*model.Storages, error) {
	_, span := otel.Start(ctx, "storages.service.GetDefault")
	defer span.End()

	tbl := table.Storages
	stmt := tbl.SELECT(tbl.AllColumns).WHERE(tbl.IsDefault.EQ(Bool(true)))
	span.SetAttributes(semconv.DBStatementKey.String(stmt.DebugSql()))

	var storage model.Storages
	if err := stmt.QueryContext(ctx, svc.db, &storage); err != nil {
		return nil, err
	}
	return &storage, nil
}

// GetStoragesByID
func (svc *Service) GetStoragesByID(ctx context.Context, ids ...int64) ([]model.Storages, error) {
	if len(ids) == 0 {
		return nil, nil
	}
	ids = lo.Uniq(ids)

	_, span := otel.Start(ctx, "storages.service.GetStoragesByID")
	defer span.End()

	tbl := table.Storages
	stmt := tbl.SELECT(tbl.AllColumns).WHERE(tbl.ID.IN(lo.Map(ids, func(i int64, _ int) Expression { return Int64(i) })...))
	span.SetAttributes(semconv.DBStatementKey.String(stmt.DebugSql()))

	var storages []model.Storages
	if err := stmt.QueryContext(ctx, svc.db, &storages); err != nil {
		return nil, err
	}
	return storages, nil
}

func (svc *Service) GetDefaultFS(ctx context.Context) (afero.Fs, error) {
	st, err := svc.GetDefault(ctx)
	if err != nil {
		return nil, err
	}
	return svc.BuildFS(st)
}

func (svc *Service) GetFSMapByIDs(ctx context.Context, ids ...int64) (map[int64]afero.Fs, error) {
	_, span := otel.Start(ctx, "storages.service.GetFSByID")
	defer span.End()

	storages, err := svc.GetStoragesByID(ctx, ids...)
	if err != nil {
		return nil, err
	}

	maps := make(map[int64]afero.Fs)
	for _, s := range storages {
		fs, err := svc.BuildFS(&s)
		if err != nil {
			return nil, err
		}
		maps[s.ID] = fs
	}

	return maps, nil
}

// GetFSByID
func (svc *Service) GetFSByID(ctx context.Context, id int64) (afero.Fs, error) {
	_, span := otel.Start(ctx, "storages.service.GetFSByID")
	defer span.End()

	storage, err := svc.GetStorageByID(ctx, id)
	if err != nil {
		return nil, err
	}

	return svc.BuildFS(storage)
}

func (svc *Service) BuildFS(storage *model.Storages) (afero.Fs, error) {
	switch storage.Type {
	case fields.StorageTypeLocal:
		return afero.NewBasePathFs(afero.NewOsFs(), storage.Config.Local.Path), nil
	}
	return nil, errors.New("invalid storage type")
}