package simplesql

import (
	"context"
	"embed"
	"fmt"
	"path/filepath"
	"strings"

	"github.com/jmoiron/sqlx"
)

// Stmts is a map of named statements
type Stmts map[string]*sqlx.NamedStmt

// Close will close all prepared statements.
// This should be called after all statements are no longer needed.
func (s *Stmts) Close() {
	for _, stmt := range *s {
		_ = stmt.Close()
	}
}

// Prepare will create a Stmts from an embed.FS.  The file name is the key.
func Prepare(ctx context.Context, db *sqlx.DB, queries embed.FS) (Stmts, error) {
	// Read entries from sqlq dir
	entries, err := queries.ReadDir("sqlq")
	if err != nil {
		return nil, fmt.Errorf("reading sqlq dir: %w", err)
	}

	// Get file content per entry and map to file name as prepared statement
	s := Stmts{}
	for _, entry := range entries {
		// Get file content
		fp := filepath.Join("sqlq", entry.Name())
		qb, err := queries.ReadFile(fp)
		if err != nil {
			return nil, fmt.Errorf("reading file %q from sqlq: %w", fp, err)
		}

		// Cleanse input query
		qs := cleanseQuery(string(qb))

		// Prepare statement
		stmt, err := db.PrepareNamedContext(ctx, qs)
		if err != nil {
			return nil, fmt.Errorf("preparing statement %q: %w", qs, err)
		}

		// Map to file name, without the extension, which is assumed to be .sql
		s[strings.TrimSuffix(entry.Name(), ".sql")] = stmt
	}

	return s, nil
}

func cleanseQuery(s string) string {
	var cleansed []string
	for _, line := range strings.Split(s, "\n") {
		line := strings.TrimSpace(line)
		if !strings.HasPrefix(line, "--") {
			cleansed = append(cleansed, line)
		}
	}

	return strings.Join(cleansed, "\n")
}