package initialise

import (
	"context"
	"embed"
	"errors"
	"fmt"

	"github.com/spf13/cobra"
	"github.com/spf13/viper"

	"github.com/zitadel/zitadel/backend/v3/instrumentation/logging"
	"github.com/zitadel/zitadel/internal/database"
)

var (
	//go:embed sql/*.sql
	stmts embed.FS

	createUserStmt           string
	grantStmt                string
	databaseStmt             string
	createEventstoreStmt     string
	createProjectionsStmt    string
	createSystemStmt         string
	createEncryptionKeysStmt string
	createEventsStmt         string
	createUniqueConstraints  string

	roleAlreadyExistsCode = "42710"
	dbAlreadyExistsCode   = "42P04"
)

func New() *cobra.Command {
	cmd := &cobra.Command{
		Use:   "init",
		Short: "initialize ZITADEL instance",
		Long: `Sets up the minimum requirements to start ZITADEL.

Prerequisites:
- PostgreSql database

The user provided by flags needs privileges to
- create the database if it does not exist
- see other users and create a new one if the user does not exist
- grant all rights of the ZITADEL database to the user created if not yet set
`,
		RunE: func(cmd *cobra.Command, args []string) (err error) {
			defer func() {
				logging.OnError(cmd.Context(), err).Error("zitadel init command failed")
			}()
			config, shutdown, err := NewConfig(cmd, viper.GetViper())
			if err != nil {
				return err
			}
			defer func() {
				err = errors.Join(err, shutdown(cmd.Context()))
			}()

			return InitAll(cmd.Context(), config)
		},
	}

	cmd.AddCommand(newZitadel(), newDatabase(), newUser(), newGrant())
	return cmd
}

func InitAll(ctx context.Context, config *Config) error {
	err := initialise(ctx, config.Database,
		VerifyUser(config.Database.Username(), config.Database.Password()),
		VerifyDatabase(config.Database.DatabaseName()),
		VerifyGrant(config.Database.DatabaseName(), config.Database.Username()),
	)
	if err != nil {
		return fmt.Errorf("initialize database failed: %w", err)
	}

	err = verifyZitadel(ctx, config.Database)
	if err != nil {
		return fmt.Errorf("initialize ZITADEL failed: %w", err)
	}
	return nil
}

func initialise(ctx context.Context, config database.Config, steps ...func(context.Context, *database.DB) error) error {
	logging.Info(ctx, "initialization started")

	err := ReadStmts()
	if err != nil {
		return err
	}

	db, err := database.Connect(config, true)
	if err != nil {
		return err
	}
	defer db.Close()

	return Init(ctx, db, steps...)
}

func Init(ctx context.Context, db *database.DB, steps ...func(context.Context, *database.DB) error) error {
	for _, step := range steps {
		if err := step(ctx, db); err != nil {
			return err
		}
	}

	return nil
}

func ReadStmts() (err error) {
	createUserStmt, err = readStmt("01_user")
	if err != nil {
		return err
	}

	databaseStmt, err = readStmt("02_database")
	if err != nil {
		return err
	}

	grantStmt, err = readStmt("03_grant_user")
	if err != nil {
		return err
	}

	createEventstoreStmt, err = readStmt("04_eventstore")
	if err != nil {
		return err
	}

	createProjectionsStmt, err = readStmt("05_projections")
	if err != nil {
		return err
	}

	createSystemStmt, err = readStmt("06_system")
	if err != nil {
		return err
	}

	createEncryptionKeysStmt, err = readStmt("07_encryption_keys_table")
	if err != nil {
		return err
	}

	createEventsStmt, err = readStmt("08_events_table")
	if err != nil {
		return err
	}

	createUniqueConstraints, err = readStmt("10_unique_constraints_table")
	if err != nil {
		return err
	}

	return nil
}

func readStmt(step string) (string, error) {
	stmt, err := stmts.ReadFile("sql/" + step + ".sql")
	return string(stmt), err
}