package store

import (
	"context"
	"fmt"
	"log/slog"
	"os"
	"time"

	"github.com/jackc/pgx/v5"
	"github.com/jackc/pgx/v5/pgxpool"
	"github.com/jackc/tern/v2/migrate"
	"github.com/knadh/goyesql/v2"
)

type (
	Queries struct {
		ExtractEntries string `query:"extract-entries"`
		UpdateCursor   string `query:"update-cursor"`
	}

	StoreOpts struct {
		Logg                 *slog.Logger
		DSN                  string
		MigrationsFolderPath string
		QueriesFolderPath    string
	}

	Store struct {
		Provider *pgxpool.Pool
		Queries  *Queries
	}
)

func NewStore(o StoreOpts) (*Store, error) {
	parsedConfig, err := pgxpool.ParseConfig(o.DSN)
	if err != nil {
		return nil, err
	}

	dbPool, err := pgxpool.NewWithConfig(context.Background(), parsedConfig)
	if err != nil {
		return nil, err
	}

	queries, err := loadQueries(o.QueriesFolderPath)
	if err != nil {
		return nil, err
	}

	if err := runMigrations(dbPool, o.MigrationsFolderPath); err != nil {
		return nil, err
	}
	o.Logg.Info("migrations ran successfully")

	return &Store{
		Provider: dbPool,
		Queries:  queries,
	}, nil
}

func (s *Store) ExecuteTransaction(ctx context.Context, fn func(tx pgx.Tx) error) error {
	tx, err := s.Provider.Begin(ctx)
	if err != nil {
		return err
	}
	defer func() {
		if err != nil {
			tx.Rollback(ctx)
		} else {
			tx.Commit(ctx)
		}
	}()

	if err = fn(tx); err != nil {
		return err
	}

	return nil
}

func loadQueries(queriesPath string) (*Queries, error) {
	parsedQueries, err := goyesql.ParseFile(queriesPath)
	if err != nil {
		return nil, err
	}

	loadedQueries := &Queries{}

	if err := goyesql.ScanToStruct(loadedQueries, parsedQueries, nil); err != nil {
		return nil, fmt.Errorf("failed to scan queries %v", err)
	}

	return loadedQueries, nil
}

func runMigrations(dbPool *pgxpool.Pool, migrationsPath string) error {
	ctx, cancel := context.WithTimeout(context.Background(), 15*time.Second)
	defer cancel()

	conn, err := dbPool.Acquire(ctx)
	if err != nil {
		return err
	}
	defer conn.Release()

	migrator, err := migrate.NewMigrator(ctx, conn.Conn(), "schema_version")
	if err != nil {
		return err
	}

	if err := migrator.LoadMigrations(os.DirFS(migrationsPath)); err != nil {
		return err
	}

	if err := migrator.Migrate(ctx); err != nil {
		return err
	}

	return nil
}