package commandkit

import (
	"fmt"

	"gitea.maximumdirect.net/eric/CommandKit/internal/alias"
	commandmeta "gitea.maximumdirect.net/eric/CommandKit/internal/commandmeta"
)

// App owns one command registry and its application identity. Each App has an
// independent registry; command declarations may be reused across Apps.
type App struct {
	identity       Identity
	commands       map[string]*commandNode
	routingRules   []RoutingRule
	aliases        *alias.Resolver
	flagAliases    map[string]resolvedFlagAliases
	discoveryFlags map[string]resolvedFlagAliases
	snapshot       *routingSnapshot
}

type routingSnapshot struct {
	metadata       *commandmeta.Command
	runners        map[commandmeta.Key]commandPayload
	aliases        *alias.Resolver
	canonical      map[string]*canonicalNode
	commandAliases []commandmeta.CommandAlias
	flagAliases    map[string]resolvedFlagAliases
	discoveryFlags map[string]resolvedFlagAliases
}

type commandNode struct {
	command Command
}

// New creates an application with the supplied identity and initial canonical
// commands and routing rules. Use []Declaration to expand a mixed declaration
// collection; []Command cannot be expanded as ...Declaration without
// converting its elements.
//
// The identity name must not be empty. New installs its generated help and
// version commands and caller declarations as one batch; an invalid, nil, or
// zero declaration returns an error without exposing an App. Factory issues
// retained in Command and RoutingRule values are reported during installation.
// Identical duplicate routing mappings are accepted; conflicting mappings
// fail the batch. The root help and version names are reserved for generated
// commands.
func New(identity Identity, declarations ...Declaration) (*App, error) {
	if identity.Name == "" {
		return nil, fmt.Errorf("application identity name must not be empty")
	}

	app := &App{identity: identity, commands: make(map[string]*commandNode)}
	builtins := app.builtinCommands()
	all := make([]Declaration, 0, len(builtins)+len(declarations))
	all = append(all, builtins...)
	all = append(all, declarations...)
	if err := app.installBatch(all...); err != nil {
		return nil, err
	}
	return app, nil
}