// Command jetgen regenerates the go-jet/v2 query-builder code under
// galaxy/gamemaster/internal/adapters/postgres/jet/ against a transient
// PostgreSQL instance.
//
// The program is intended to be invoked as `go run ./cmd/jetgen` (or via
// the `make jet` Makefile target) from within `galaxy/gamemaster`. It is
// not part of the runtime binary.
//
// Steps:
//
//  1. start a postgres:16-alpine container via testcontainers-go
//  2. open it through pkg/postgres as the superuser
//  3. CREATE ROLE gamemasterservice and CREATE SCHEMA "gamemaster"
//     AUTHORIZATION gamemasterservice
//  4. open a second pool as gamemasterservice with search_path=gamemaster
//     and apply the embedded goose migrations
//  5. run jet's PostgreSQL generator against schema=gamemaster, writing
//     into ../internal/adapters/postgres/jet
package main

import (
	"context"
	"errors"
	"fmt"
	"log"
	"net/url"
	"os"
	"path/filepath"
	"runtime"
	"time"

	"galaxy/postgres"

	"galaxy/gamemaster/internal/adapters/postgres/migrations"

	jetpostgres "github.com/go-jet/jet/v2/generator/postgres"
	testcontainers "github.com/testcontainers/testcontainers-go"
	tcpostgres "github.com/testcontainers/testcontainers-go/modules/postgres"
	"github.com/testcontainers/testcontainers-go/wait"
)

const (
	postgresImage      = "postgres:16-alpine"
	superuserName      = "galaxy"
	superuserPassword  = "galaxy"
	superuserDatabase  = "galaxy_gamemaster"
	serviceRole        = "gamemasterservice"
	servicePassword    = "gamemasterservice"
	serviceSchema      = "gamemaster"
	containerStartup   = 90 * time.Second
	defaultOpTimeout   = 10 * time.Second
	jetOutputDirSuffix = "internal/adapters/postgres/jet"
)

func main() {
	if err := run(context.Background()); err != nil {
		log.Fatalf("jetgen: %v", err)
	}
}

func run(ctx context.Context) error {
	outputDir, err := jetOutputDir()
	if err != nil {
		return err
	}

	container, err := tcpostgres.Run(ctx, postgresImage,
		tcpostgres.WithDatabase(superuserDatabase),
		tcpostgres.WithUsername(superuserName),
		tcpostgres.WithPassword(superuserPassword),
		testcontainers.WithWaitStrategy(
			wait.ForLog("database system is ready to accept connections").
				WithOccurrence(2).
				WithStartupTimeout(containerStartup),
		),
	)
	if err != nil {
		return fmt.Errorf("start postgres container: %w", err)
	}
	defer func() {
		if termErr := testcontainers.TerminateContainer(container); termErr != nil {
			log.Printf("jetgen: terminate container: %v", termErr)
		}
	}()

	baseDSN, err := container.ConnectionString(ctx, "sslmode=disable")
	if err != nil {
		return fmt.Errorf("resolve container dsn: %w", err)
	}

	if err := provisionRoleAndSchema(ctx, baseDSN); err != nil {
		return err
	}

	scopedDSN, err := dsnForServiceRole(baseDSN)
	if err != nil {
		return err
	}
	if err := applyMigrations(ctx, scopedDSN); err != nil {
		return err
	}

	if err := os.RemoveAll(outputDir); err != nil {
		return fmt.Errorf("remove existing jet output %q: %w", outputDir, err)
	}
	if err := os.MkdirAll(filepath.Dir(outputDir), 0o755); err != nil {
		return fmt.Errorf("ensure jet output parent: %w", err)
	}

	jetCfg := postgres.DefaultConfig()
	jetCfg.PrimaryDSN = scopedDSN
	jetCfg.OperationTimeout = defaultOpTimeout
	jetDB, err := postgres.OpenPrimary(ctx, jetCfg)
	if err != nil {
		return fmt.Errorf("open scoped pool for jet generation: %w", err)
	}
	defer func() { _ = jetDB.Close() }()

	if err := jetpostgres.GenerateDB(jetDB, serviceSchema, outputDir); err != nil {
		return fmt.Errorf("jet generate: %w", err)
	}

	log.Printf("jetgen: generated jet code into %s (schema=%s)", outputDir, serviceSchema)
	return nil
}

func provisionRoleAndSchema(ctx context.Context, baseDSN string) error {
	cfg := postgres.DefaultConfig()
	cfg.PrimaryDSN = baseDSN
	cfg.OperationTimeout = defaultOpTimeout
	db, err := postgres.OpenPrimary(ctx, cfg)
	if err != nil {
		return fmt.Errorf("open admin pool: %w", err)
	}
	defer func() { _ = db.Close() }()

	statements := []string{
		fmt.Sprintf(`DO $$ BEGIN
			IF NOT EXISTS (SELECT 1 FROM pg_roles WHERE rolname = %s) THEN
				CREATE ROLE %s LOGIN PASSWORD %s;
			END IF;
		END $$;`, sqlLiteral(serviceRole), sqlIdentifier(serviceRole), sqlLiteral(servicePassword)),
		fmt.Sprintf(`CREATE SCHEMA IF NOT EXISTS %s AUTHORIZATION %s;`,
			sqlIdentifier(serviceSchema), sqlIdentifier(serviceRole)),
		fmt.Sprintf(`GRANT USAGE ON SCHEMA %s TO %s;`,
			sqlIdentifier(serviceSchema), sqlIdentifier(serviceRole)),
	}
	for _, statement := range statements {
		if _, err := db.ExecContext(ctx, statement); err != nil {
			return fmt.Errorf("provision %q/%q: %w", serviceSchema, serviceRole, err)
		}
	}
	return nil
}

func dsnForServiceRole(baseDSN string) (string, error) {
	parsed, err := url.Parse(baseDSN)
	if err != nil {
		return "", fmt.Errorf("parse base dsn: %w", err)
	}
	values := url.Values{}
	values.Set("search_path", serviceSchema)
	values.Set("sslmode", "disable")
	scoped := url.URL{
		Scheme:   parsed.Scheme,
		User:     url.UserPassword(serviceRole, servicePassword),
		Host:     parsed.Host,
		Path:     parsed.Path,
		RawQuery: values.Encode(),
	}
	return scoped.String(), nil
}

func applyMigrations(ctx context.Context, dsn string) error {
	cfg := postgres.DefaultConfig()
	cfg.PrimaryDSN = dsn
	cfg.OperationTimeout = defaultOpTimeout
	db, err := postgres.OpenPrimary(ctx, cfg)
	if err != nil {
		return fmt.Errorf("open scoped pool: %w", err)
	}
	defer func() { _ = db.Close() }()

	if err := postgres.Ping(ctx, db, defaultOpTimeout); err != nil {
		return err
	}
	if err := postgres.RunMigrations(ctx, db, migrations.FS(), "."); err != nil {
		return fmt.Errorf("run migrations: %w", err)
	}
	return nil
}

// jetOutputDir returns the absolute path that jet should write into. We
// rely on the runtime caller info to anchor it to galaxy/gamemaster
// regardless of the invoking working directory.
func jetOutputDir() (string, error) {
	_, file, _, ok := runtime.Caller(0)
	if !ok {
		return "", errors.New("resolve runtime caller for jet output path")
	}
	dir := filepath.Dir(file)
	// dir = .../galaxy/gamemaster/cmd/jetgen
	moduleRoot := filepath.Clean(filepath.Join(dir, "..", ".."))
	return filepath.Join(moduleRoot, jetOutputDirSuffix), nil
}

func sqlIdentifier(name string) string {
	return `"` + escapeDoubleQuotes(name) + `"`
}

func sqlLiteral(value string) string {
	return "'" + escapeSingleQuotes(value) + "'"
}

func escapeDoubleQuotes(value string) string {
	out := make([]byte, 0, len(value))
	for index := 0; index < len(value); index++ {
		if value[index] == '"' {
			out = append(out, '"', '"')
			continue
		}
		out = append(out, value[index])
	}
	return string(out)
}

func escapeSingleQuotes(value string) string {
	out := make([]byte, 0, len(value))
	for index := 0; index < len(value); index++ {
		if value[index] == '\'' {
			out = append(out, '\'', '\'')
			continue
		}
		out = append(out, value[index])
	}
	return string(out)
}