// Package lifecycle adapts Goose providers to startup policy and native commands.
// Callers own database modules and supply fresh, late-bound providers.
package lifecycle

import (
	"context"
	"errors"
	"fmt"
	"strconv"
	"strings"
	"text/tabwriter"

	"github.com/pressly/goose/v3"
	urfavecli "github.com/urfave/cli/v3"
	"go.auvem.com/corestack/lifecycle"
	"go.auvem.com/corestack/lifecycle/cli"
)

// Policy selects migration behavior during module setup.
type Policy string

const (
	// Apply runs pending migrations before later modules start.
	Apply Policy = "apply"
	// Require fails setup when migrations are pending. This is a point-in-time
	// check, not a deployment lock; Goose may initialize its version table.
	Require Policy = "require"
)

// Module declares startup migration work without resolving provider yet.
// Register it after the database module and before dependent modules. The
// resolver must return fresh registrations and clean up any partial acquisition.
// Teardown never closes the provider: the database module owns its database.
func Module(name string, policy Policy, provider func(context.Context) (*goose.Provider, error)) (lifecycle.Module, error) {
	if name == "" || (policy != Apply && policy != Require) || provider == nil {
		return lifecycle.Module{}, errors.New("migrate: name, apply/require policy and provider resolver are required")
	}
	return lifecycle.Module{Name: name, Teardown: func(context.Context) error { return nil }, Setup: func(ctx context.Context) error {
		p, err := resolve(ctx, provider)
		if err != nil {
			return err
		}
		if policy == Apply {
			_, err = p.Up(ctx)
		} else {
			var pending bool
			pending, err = p.HasPending(ctx)
			if err == nil && pending {
				return errors.New("migrate: pending migrations; run migrate up before startup")
			}
		}
		if err != nil {
			return fmt.Errorf("migrate: %s: %w", policy, err)
		}
		return nil
	}}, nil
}

func resolve(ctx context.Context, provider func(context.Context) (*goose.Provider, error)) (*goose.Provider, error) {
	if provider == nil {
		return nil, errors.New("migrate: provider resolver is required")
	}
	p, err := provider(ctx)
	if err != nil {
		return nil, fmt.Errorf("migrate: resolve provider: %w", err)
	}
	if p == nil {
		return nil, errors.New("migrate: resolver returned nil provider")
	}
	return p, nil
}

// Commands returns a fresh native migrate group using exactly modules, with
// services suppressed. Supply database modules only, excluding startup policy.
// Resolvers run after setup. Help/usage starts nothing; Action owns signals and
// reverse cleanup. Use fresh trees and bindings for independent invocations.
// Status may initialize the version table; it does not run migration bodies.
func Commands(config lifecycle.Config, modules []lifecycle.Module, provider func(context.Context) (*goose.Provider, error)) *urfavecli.Command {
	group := &urfavecli.Command{Name: "migrate", Usage: "Manage database migrations"}
	for _, name := range []string{"up", "up-to", "down", "down-to", "status"} {
		targeted := strings.HasSuffix(name, "-to")
		leaf := &urfavecli.Command{Name: name, ArgValidator: func(_ context.Context, cmd *urfavecli.Command) error {
			if targeted {
				if cmd.NArg() == 1 {
					if _, err := version(cmd.Args().First()); err == nil {
						return nil
					}
				}
				return urfavecli.Exit("expected one nonnegative decimal int64 version", 2)
			}
			if cmd.NArg() != 0 {
				return urfavecli.Exit("unexpected positional arguments", 2)
			}
			return nil
		}}
		if targeted {
			leaf.ArgsUsage = "<version>"
		}
		leaf.Action = cli.Action(config, modules, func(ctx context.Context, cmd *urfavecli.Command) error {
			p, err := resolve(ctx, provider)
			if err != nil {
				return err
			}
			target, _ := version(cmd.Args().First()) // ArgValidator checked targeted leaves before setup.
			switch name {
			case "up":
				_, err = p.Up(ctx)
			case "up-to":
				_, err = p.UpTo(ctx, target)
			case "down":
				_, err = p.Down(ctx)
			case "down-to":
				_, err = p.DownTo(ctx, target)
			case "status":
				var statuses []*goose.MigrationStatus
				statuses, err = p.Status(ctx)
				if err == nil {
					writer := tabwriter.NewWriter(cmd.Writer, 0, 4, 2, ' ', 0)
					if _, err = fmt.Fprintln(writer, "VERSION\tSTATE\tSOURCE"); err == nil {
						for _, status := range statuses {
							if _, err = fmt.Fprintf(writer, "%d\t%s\t%s\n", status.Source.Version, status.State, status.Source.Path); err != nil {
								break
							}
						}
					}
					if err == nil {
						err = writer.Flush()
					}
				}
			}
			if err != nil {
				return fmt.Errorf("migrate %s: %w", name, err)
			}
			return nil
		})
		group.Commands = append(group.Commands, leaf)
	}
	return group
}

func version(raw string) (int64, error) {
	if raw == "" || strings.IndexFunc(raw, func(r rune) bool { return r < '0' || r > '9' }) >= 0 {
		return 0, errors.New("invalid version")
	}
	return strconv.ParseInt(raw, 10, 64)
}