// Command mesh-control is the control plane: everything that needs to know about more than one
// node (novox/hq ADR 0006).
//
// It runs as one process holding several contexts, each owning its own store. Today it holds one,
// `inventory`, and does one thing with it — brings its schema up to date, which is step 3 of the
// bootstrap in novox/hq 07-the-substrate and the step the first node cannot get past without.
package main

import (
	"context"
	"flag"
	"fmt"
	"os"
	"os/signal"
	"syscall"

	"github.com/novox/mesh-control/internal/identity"
	"github.com/novox/mesh-control/internal/inventory"
	"github.com/novox/mesh-control/internal/licences"
	"github.com/novox/mesh-control/internal/link"
	"github.com/novox/mesh-control/internal/store"
)

// version is stamped at link time. Unset in a development build, and it says so rather than
// claiming a number.
var version = "development build"

// held is a context this process was granted, and the schema it carries.
//
// novox/hq ADR 0006 names seven. One is built. The list is short because the others do not exist
// yet, not because they are optional.
var held = []struct {
	name       string
	migrations func() ([]store.Migration, error)
}{
	{inventory.Name, inventory.Migrations},
	{identity.Name, identity.Migrations},
	{licences.Name, licences.Migrations},
}

func main() {
	if err := run(); err != nil {
		fmt.Fprintf(os.Stderr, "mesh-control: %v\n", err)
		os.Exit(1)
	}
}

func run() error {
	args := os.Args[1:]
	if len(args) == 0 {
		usage()
		return fmt.Errorf("no command given")
	}

	ctx, stop := signal.NotifyContext(context.Background(), syscall.SIGINT, syscall.SIGTERM)
	defer stop()

	switch args[0] {
	case "build":
		return buildCommand(ctx, args[1:])
	case "builder":
		return builderCommand(ctx, args[1:])
	case "board":
		return boardCommand(ctx, args[1:])
	case "api":
		return apiCommand(ctx, args[1:])
	case "licence":
		return licenceCommand(ctx, args[1:])
	case "rotate":
		return rotateCommand(ctx, args[1:])
	case "builds":
		return buildsCommand(ctx, args[1:])
	case "pin":
		return pinCommand(ctx, args[1:], true)
	case "unpin":
		return pinCommand(ctx, args[1:], false)
	case "migrate":
		return migrate(ctx)
	case "node":
		return nodeCommand(ctx, args[1:])
	case "token":
		return tokenCommand(ctx, args[1:])
	case "identity":
		return identityCommand(ctx, args[1:])
	case "broker":
		return brokerCommand(args[1:])
	case "serve":
		return serve(ctx)
	case "declare":
		return declare(ctx, args[1:])
	case "overlay":
		return overlayCommand(ctx, args[1:])
	case "module":
		return moduleCommand(ctx, args[1:])
	case "assign", "unassign":
		return assignCommand(ctx, args[0], args[1:])
	case "settings":
		return settingsCommand(ctx, args[1:])
	case "secret":
		return secretCommand(ctx, args[1:])
	case "plan":
		return planCommand(ctx, args[1:])
	case "push":
		return pushCommand(ctx, args[1:])
	case "status":
		return statusCommand(ctx, args[1:])
	case "version":
		fmt.Println(version)
		return nil
	case "help", "-h", "--help":
		usage()
		return nil
	default:
		usage()
		return fmt.Errorf("%q is not a command", args[0])
	}
}

func usage() {
	fmt.Fprint(os.Stderr, `mesh-control — the control plane

  migrate                        bring each context's schema up to date
  node add <name>                create a node record
  node list                      the nodes this mesh knows about
  node show <name>               what one machine reported it can do, and why
  token issue --node <name>      a one-time right to join, for an existing record
  token issue --new <name>       create the record and issue for it
  identity show                  this control plane's signing key
  broker show                    where the broker is, and what to expect there
  serve                          consume what nodes say, and answer
  declare <node> <file>          send a node a signed declaration
  overlay place <node> [flags]   say where a node is and how it is reached
  overlay show                   the private network, as the mesh computes it
  module add <file>              register a module from its manifest
  module list                    what modules this mesh knows about
  module moved <name> <commit>   the source has a newer commit than the mesh built
  module forget <name>           remove one, unless a node is running it
  module issue <name> --node <m> a broker account for a module, scoped to its emits and consumes
  status [--json]                what is wrong, what is quiet, and what is out of date
  board [--listen ADDR]          the same three questions, as a page that holds nothing
  api --issuer URL [--listen A]  assign and unassign over http, for a surface that is not here
  assign <node> <module>         put a module on a node
  unassign <node> <module>       take it off
  settings set <module> <file>   what a module's config should say, for the whole mesh
  settings set <module> <file> --node <n>   ...or for one machine
  settings clear <module> [--node <n>]      take a layer away
  secret accept <node> <module> <name>     carry a value the mesh did not make and cannot invent
  secret accept ... --from <file>           ...read it from a file rather than being asked
  build <repository> [--ref R]   have a build machine build it, and record what came out
  build --behind                 build every module the mesh holds older than its source
  builds [<module>]              what has been built lately, and what came of it
  builder issue <name>           a broker account for a build machine, scoped to build work
  licence add|list|use|key       model access, under the name a person calls it
  rotate <provision> [--consumer <n>]  a new credential for every holder, both ends at once
  pin <node> <provision> <from>  which node this one gets a provision from
  unpin <node> <provision>       put that question back
  plan <node> [--files|--json]     what that node would run, and why
  push [<node>] [--behind]       send a node everything it should be, or only those that need it
  version                        what this binary is

Each context reaches its own store through its own credential (novox/hq ADR 0008), named
`+store.Variable("<context>")+`. This process holds:

`)
	for _, c := range held {
		fmt.Fprintf(os.Stderr, "  %-12s database %-12s from %s\n",
			c.name, store.Database(c.name), store.Variable(c.name))
	}
	fmt.Fprintln(os.Stderr)
}

// parseAround reads flags that may sit before, after or between positional arguments.
//
// The standard library stops at the first non-flag argument, so `module add thing.json --source x`
// parses no flags at all and silently ignores every one of them. The host learned this the same
// way and says so in its own parser: a flag that is quietly dropped is the fault this project
// keeps naming, and it looks exactly like success.
func parseAround(set *flag.FlagSet, args []string) ([]string, error) {
	var positionals []string
	rest := args
	for {
		if err := set.Parse(rest); err != nil {
			return nil, err
		}
		rest = set.Args()
		if len(rest) == 0 {
			return positionals, nil
		}
		positionals = append(positionals, rest[0])
		rest = rest[1:]
	}
}

func (b builds) Built(ctx context.Context, result link.BuildResult) error {
	return b.inv.RecordBuild(ctx, buildFrom(result))
}