// Package database provides SQLite database access with logging.
package database

import (
	"context"
	"crypto/sha256"
	"database/sql"
	"encoding/hex"
	"fmt"
	"log/slog"
	"os"
	"path/filepath"

	_ "github.com/mattn/go-sqlite3" // SQLite driver
	"go.uber.org/fx"

	"git.eeqj.de/sneak/upaas/internal/config"
	"git.eeqj.de/sneak/upaas/internal/logger"
)

// dataDirPermissions is the file permission for the data directory.
const dataDirPermissions = 0o750

// Params contains dependencies for Database.
type Params struct {
	fx.In

	Logger *logger.Logger
	Config *config.Config
}

// Database wraps sql.DB with logging and helper methods.
type Database struct {
	database *sql.DB
	log      *slog.Logger
	params   *Params
}

// New creates a new Database instance.
func New(lifecycle fx.Lifecycle, params Params) (*Database, error) {
	database := &Database{
		log:    params.Logger.Get(),
		params: &params,
	}

	// For testing, if lifecycle is nil, connect immediately
	if lifecycle == nil {
		err := database.connect(context.Background())
		if err != nil {
			return nil, err
		}

		return database, nil
	}

	lifecycle.Append(fx.Hook{
		OnStart: func(ctx context.Context) error {
			return database.connect(ctx)
		},
		OnStop: func(_ context.Context) error {
			return database.close()
		},
	})

	return database, nil
}

// DB returns the underlying sql.DB for direct access.
func (d *Database) DB() *sql.DB {
	return d.database
}

// Exec executes a query with logging.
func (d *Database) Exec(
	ctx context.Context,
	query string,
	args ...any,
) (sql.Result, error) {
	d.log.Debug("database exec", "query", query, "args", args)

	result, err := d.database.ExecContext(ctx, query, args...)
	if err != nil {
		return nil, fmt.Errorf("exec failed: %w", err)
	}

	return result, nil
}

// QueryRow executes a query that returns a single row.
func (d *Database) QueryRow(ctx context.Context, query string, args ...any) *sql.Row {
	d.log.Debug("database query row", "query", query, "args", args)

	return d.database.QueryRowContext(ctx, query, args...)
}

// Query executes a query that returns multiple rows.
func (d *Database) Query(
	ctx context.Context,
	query string,
	args ...any,
) (*sql.Rows, error) {
	d.log.Debug("database query", "query", query, "args", args)

	rows, err := d.database.QueryContext(ctx, query, args...)
	if err != nil {
		return nil, fmt.Errorf("query failed: %w", err)
	}

	return rows, nil
}

// BeginTx starts a new transaction.
func (d *Database) BeginTx(ctx context.Context, opts *sql.TxOptions) (*sql.Tx, error) {
	d.log.Debug("database begin transaction")

	transaction, err := d.database.BeginTx(ctx, opts)
	if err != nil {
		return nil, fmt.Errorf("begin transaction failed: %w", err)
	}

	return transaction, nil
}

// Path returns the database file path.
func (d *Database) Path() string {
	return d.params.Config.DatabasePath()
}

func (d *Database) connect(ctx context.Context) error {
	dbPath := d.params.Config.DatabasePath()

	// Ensure data directory exists
	dir := filepath.Dir(dbPath)

	err := os.MkdirAll(dir, dataDirPermissions)
	if err != nil {
		return fmt.Errorf("failed to create data directory: %w", err)
	}

	// Open database with WAL mode and foreign keys
	dsn := dbPath + "?_journal_mode=WAL&_foreign_keys=on"

	database, err := sql.Open("sqlite3", dsn)
	if err != nil {
		return fmt.Errorf("failed to open database: %w", err)
	}

	// Test connection
	err = database.PingContext(ctx)
	if err != nil {
		return fmt.Errorf("failed to ping database: %w", err)
	}

	d.database = database
	d.log.Info("database connected", "path", dbPath)

	// Run migrations
	err = d.migrate(ctx)
	if err != nil {
		return fmt.Errorf("failed to run migrations: %w", err)
	}

	// Backfill webhook_secret_hash for any rows that have a secret but no hash
	err = d.backfillWebhookSecretHashes(ctx)
	if err != nil {
		return fmt.Errorf("failed to backfill webhook secret hashes: %w", err)
	}

	return nil
}

// HashWebhookSecret returns the hex-encoded SHA-256 hash of a webhook secret.
func HashWebhookSecret(secret string) string {
	sum := sha256.Sum256([]byte(secret))

	return hex.EncodeToString(sum[:])
}

func (d *Database) backfillWebhookSecretHashes(ctx context.Context) error {
	rows, err := d.database.QueryContext(ctx,
		"SELECT id, webhook_secret FROM apps WHERE webhook_secret_hash = '' AND webhook_secret != ''")
	if err != nil {
		return fmt.Errorf("querying apps for backfill: %w", err)
	}

	defer func() { _ = rows.Close() }()

	type row struct {
		id, secret string
	}

	var toUpdate []row

	for rows.Next() {
		var r row

		scanErr := rows.Scan(&r.id, &r.secret)
		if scanErr != nil {
			return fmt.Errorf("scanning app for backfill: %w", scanErr)
		}

		toUpdate = append(toUpdate, r)
	}

	rowsErr := rows.Err()
	if rowsErr != nil {
		return fmt.Errorf("iterating apps for backfill: %w", rowsErr)
	}

	for _, r := range toUpdate {
		hash := HashWebhookSecret(r.secret)

		_, updateErr := d.database.ExecContext(ctx,
			"UPDATE apps SET webhook_secret_hash = ? WHERE id = ?", hash, r.id)
		if updateErr != nil {
			return fmt.Errorf("updating webhook_secret_hash for app %s: %w", r.id, updateErr)
		}

		d.log.Info("backfilled webhook_secret_hash", "app_id", r.id)
	}

	return nil
}

func (d *Database) close() error {
	if d.database != nil {
		d.log.Info("closing database connection")

		err := d.database.Close()
		if err != nil {
			return fmt.Errorf("failed to close database: %w", err)
		}
	}

	return nil
}