// Package dispatch is the Crucible command surface: a single registry of
// builders shared by the `crucible` dispatcher and the standalone
// `crucible-<name>` shims.
//
// Cutover state (Phase 5 → 6): the internal pipeline/topdata/erf/wiki
// packages migrated from gitea/sow-tools now live in this tree, so wired
// builders delegate to internal/app's legacy command surface (mapped per
// docs/command-surface.md). A builder with no migrated logic yet (depot) keeps
// the Wired=false fail-closed path: exit 70, never a faked artifact.
package dispatch

import (
	"fmt"
	"io"
	"os"

	"git.westgate.pw/ShadowsOverWestgate/sow-tools/internal/app"
	"git.westgate.pw/ShadowsOverWestgate/sow-tools/internal/buildinfo"
	"git.westgate.pw/ShadowsOverWestgate/sow-tools/internal/depot"
	"git.westgate.pw/ShadowsOverWestgate/sow-tools/internal/menu"
)

// Exit codes follow the sysexits(3) convention so CI can distinguish
// "you called it wrong" from "the tool is not wired yet".
const (
	exitOK      = 0
	exitUsage   = 64 // EX_USAGE — bad invocation / unknown builder
	exitUnwired = 70 // EX_SOFTWARE — builder registered but not yet implemented
)

// Builder is one tool surface in the Crucible suite.
type Builder struct {
	Name     string    // canonical dispatcher subcommand, e.g. "module"
	Bin      string    // standalone binary name, e.g. "crucible-module"
	Summary  string    // one-line description
	Commands []Command // visible commands plus hidden compatibility aliases
	Wired    bool      // true once the builder delegates to migrated internal/app logic
}

// Command is one public builder action. AppCommand names the unchanged
// internal/app implementation command. Aliases remain callable for compatibility
// but are omitted from routine help and the interactive menu.
type Command struct {
	Name       string
	Summary    string
	AppCommand string
	Usage      string
	Options    []string
	Aliases    []CommandAlias
}

type CommandAlias struct {
	Name       string
	AppCommand string
}

func (b Builder) subcommands() []string {
	commands := make([]string, 0, len(b.Commands))
	for _, command := range b.Commands {
		commands = append(commands, command.Name)
	}
	return commands
}

func (b Builder) command(name string) (Command, string, bool) {
	for _, command := range b.Commands {
		if command.Name == name {
			return command, command.AppCommand, true
		}
		for _, alias := range command.Aliases {
			if alias.Name == name {
				target := alias.AppCommand
				if target == "" {
					target = command.AppCommand
				}
				return command, target, true
			}
		}
	}
	return Command{}, "", false
}

func (b Builder) accepts(sub string) bool {
	_, _, ok := b.command(sub)
	return ok
}

// Registry is the single source of truth for the Crucible command surface.
// Keep it in sync with docs/command-surface.md and the cmd/ directory.
var Registry = []Builder{
	{
		Name:    "depot",
		Bin:     "crucible-depot",
		Summary: "verify/move content-addressed depot blobs (SeaweedFS)",
		Wired:   false, // no migrated logic yet; fails closed (exit 70)
	},
	{
		Name:    "hak",
		Bin:     "crucible-hak",
		Summary: "pack/unpack ERF/HAK archives + hak manifests",
		Commands: []Command{
			{
				Name:       "build",
				Summary:    "build configured HAK archives and their manifest",
				AppCommand: "build-haks",
				Usage:      "crucible hak build [options]",
				Options: []string{
					"--hak <name>                    build selected configured HAKs",
					"--archive <name>                build selected archive members",
					"--source-manifest <path>        read a generated source manifest",
					"--content-addressed-root <path> resolve source-manifest blobs here",
					"--plan-only                     plan outputs without writing archives",
					"--quiet | --verbose | --debug   select output detail",
				},
				Aliases: []CommandAlias{{Name: "build-haks"}},
			},
			{
				Name:       "manifest",
				Summary:    "apply a generated HAK list to the module source",
				AppCommand: "apply-hak-manifest",
				Usage:      "crucible hak manifest [manifest-path]",
				Aliases:    []CommandAlias{{Name: "apply-hak-manifest"}},
			},
		},
		Wired: true,
	},
	{
		Name:    "module",
		Bin:     "crucible-module",
		Summary: "build/extract/validate/compare the .mod",
		Commands: []Command{
			{
				Name:       "build",
				Summary:    "build the module and configured project outputs",
				AppCommand: "build",
				Usage:      "crucible module build [--quiet|--verbose|--debug]",
				Aliases:    []CommandAlias{{Name: "build-module", AppCommand: "build-module"}},
			},
			{
				Name:       "extract",
				Summary:    "extract built archives into configured source trees",
				AppCommand: "extract",
				Usage:      "crucible module extract [resource ...]",
			},
			{
				Name:       "validate",
				Summary:    "validate project layout, config, and source inventory",
				AppCommand: "validate",
				Usage:      "crucible module validate",
			},
			{
				Name:       "compare",
				Summary:    "compare source content with built module and HAK archives",
				AppCommand: "compare",
				Usage:      "crucible module compare",
			},
			{
				Name:       "manifest",
				Summary:    "apply a generated HAK list to the module source",
				AppCommand: "apply-hak-manifest",
				Usage:      "crucible module manifest [manifest-path]",
				Aliases:    []CommandAlias{{Name: "apply-hak-manifest"}},
			},
		},
		Wired: true,
	},
	{
		Name:    "topdata",
		Bin:     "crucible-topdata",
		Summary: "compile 2da/tlk topdata + packages",
		Commands: []Command{
			{
				Name:       "validate",
				Summary:    "validate topdata layout and canonical JSON compatibility",
				AppCommand: "validate-topdata",
				Usage:      "crucible topdata validate",
				Aliases:    []CommandAlias{{Name: "validate-topdata"}},
			},
			{
				Name:       "build",
				Summary:    "compile topdata and refresh the configured package",
				AppCommand: "build-topdata",
				Usage:      "crucible topdata build [--force] [--wiki] [--skip-lfs]",
				Options: []string{
					"--force      rebuild outputs even when current",
					"--wiki       build wiki drafts after compilation",
					"--skip-lfs   skip Git LFS materialization",
				},
				Aliases: []CommandAlias{{Name: "build-topdata"}},
			},
			{
				Name:       "package",
				Summary:    "package cached topdata outputs into HAK and TLK files",
				AppCommand: "build-top-package",
				Usage:      "crucible topdata package [--force] [--skip-lfs]",
				Options: []string{
					"--force      rebuild outputs even when current",
					"--skip-lfs   skip Git LFS materialization",
				},
				Aliases: []CommandAlias{{Name: "build-top-package"}},
			},
			{
				Name:       "compare",
				Summary:    "compare current output with a fresh native build",
				AppCommand: "compare-topdata",
				Usage:      "crucible topdata compare",
				Aliases:    []CommandAlias{{Name: "compare-topdata"}},
			},
			{
				Name:       "convert",
				Summary:    "convert between 2DA and native JSON/module formats",
				AppCommand: "convert-topdata",
				Usage:      "crucible topdata convert <2da-to-json|2da-to-module|json-to-2da> ...",
				Options: []string{
					"2da-to-json <input.2da> <output.json>",
					"2da-to-module [flags] <input.2da> [output.json]",
					"json-to-2da <input.json> <output.2da>",
				},
				Aliases:    []CommandAlias{{Name: "convert-topdata"}},
			},
		},
		Wired: true,
	},
	{
		Name:    "wiki",
		Bin:     "crucible-wiki",
		Summary: "render + deploy mechanical wiki pages",
		Commands: []Command{
			{
				Name:       "build",
				Summary:    "render wiki page drafts from compiled topdata",
				AppCommand: "build-wiki",
				Usage:      "crucible wiki build [--force]",
				Options:    []string{"--force   rebuild drafts even when current"},
				Aliases:    []CommandAlias{{Name: "build-wiki"}},
			},
			{
				Name:       "deploy",
				Summary:    "deploy generated wiki pages to NodeBB",
				AppCommand: "deploy-wiki",
				Usage:      "crucible wiki deploy [options]",
				Options: []string{
					"--source-dir <path>              read generated pages here",
					"--endpoint <url>                 override the NodeBB endpoint",
					"--token <token>                  authenticate with an API token",
					"--username/--password <value>    authenticate with credentials",
					"--version <version>              label the deployed revision",
					"--namespace <name>               deploy selected namespaces",
					"--category <namespace=id>        override a namespace category",
					"--manifest <path>                write deployment state here",
					"--stale-policy <policy>          report, archive, or purge",
					"--dry-run                        report changes without writing",
					"--create                         allow missing pages to be created",
					"--force                          update unchanged pages",
					"--reset-managed-namespaces       reset managed namespace state",
				},
				Aliases: []CommandAlias{{Name: "deploy-wiki"}},
			},
		},
		Wired: true,
	},
}

func find(name string) (Builder, bool) {
	for _, b := range Registry {
		if b.Name == name {
			return b, true
		}
	}
	return Builder{}, false
}

// Main is the `crucible` dispatcher entrypoint. With no arguments on an
// interactive terminal it launches the menu; otherwise (pipes, CI) it prints
// usage, preserving scriptable behavior.
func Main(args []string) int {
	if len(args) == 0 && interactive(os.Stdout) {
		return runMenu(os.Stdout, os.Stderr, os.Stdin)
	}
	return run(args, os.Stdout, os.Stderr)
}

func interactive(f *os.File) bool {
	fi, err := f.Stat()
	if err != nil {
		return false
	}
	return fi.Mode()&os.ModeCharDevice != 0
}

func menuItems() []menu.Item {
	var items []menu.Item
	for _, b := range Registry {
		if !b.Wired {
			continue
		}
		for _, sub := range b.subcommands() {
			command, _, _ := b.command(sub)
			items = append(items, menu.Item{
				Label: b.Name + " " + sub,
				Desc:  command.Summary,
				Args:  []string{b.Name, sub},
				Usage: command.Usage,
				Options: append([]string(nil),
					command.Options...),
			})
		}
	}
	return items
}

func runMenu(out, errw io.Writer, in io.Reader) int {
	chosen, err := menu.Select(out, in, menuItems())
	if err != nil {
		fmt.Fprintln(errw, "crucible:", err)
		return exitUsage
	}
	if chosen == nil {
		return exitOK
	}
	return run(chosen, out, errw)
}

// RunBuilder is the standalone `crucible-<name>` entrypoint.
func RunBuilder(name string, args []string) int {
	return runBuilder(name, args, os.Stdout, os.Stderr)
}

func run(args []string, out, errw io.Writer) int {
	if len(args) == 0 {
		usage(out)
		return exitUsage
	}
	switch args[0] {
	case "-h", "--help", "help":
		usage(out)
		return exitOK
	case "-V", "--version", "version":
		fmt.Fprintln(out, buildinfo.String())
		return exitOK
	case "list":
		list(out)
		return exitOK
	case "config":
		// Global concern shared by every builder (command-surface.md): the legacy
		// `config` command group, surfaced verbatim.
		return delegateLegacy(args, errw)
	case "changelog":
		// Release tooling: global alias for the legacy `build-changelog` command.
		return delegateLegacy(append([]string{"build-changelog"}, args[1:]...), errw)
	}
	return runBuilder(args[0], args[1:], out, errw)
}

func runBuilder(name string, args []string, out, errw io.Writer) int {
	b, ok := find(name)
	if !ok {
		fmt.Fprintf(errw, "crucible: unknown builder %q\n\n", name)
		usage(errw)
		return exitUsage
	}
	if len(args) > 0 {
		switch args[0] {
		case "-h", "--help", "help":
			builderHelp(out, b)
			return exitOK
		}
	}
	if b.Name == "depot" && b.Wired {
		// depot parses its own subcommand (status/push/verify/get/pull) and
		// has its own richer exit contract (0/1/2/64/70), so it bypasses the
		// b.Commands/delegateLegacy routing entirely.
		return depot.Run(args, out, errw, os.Getenv)
	}
	if !b.Wired {
		// No migrated logic yet (depot): fail closed, never fake an artifact.
		fmt.Fprintf(errw, unwiredMsg, b.Name, b.Bin)
		return exitUnwired
	}
	if len(args) == 0 {
		fmt.Fprintf(errw, "crucible %s: a subcommand is required\n\n", b.Name)
		builderHelp(errw, b)
		return exitUsage
	}
	sub := args[0]
	command, appCommand, ok := b.command(sub)
	if !ok {
		fmt.Fprintf(errw, "crucible %s: unknown subcommand %q\n\n", b.Name, sub)
		builderHelp(errw, b)
		return exitUsage
	}
	if len(args) > 1 {
		switch args[1] {
		case "-h", "--help", "help":
			commandHelp(out, command)
			return exitOK
		}
	}
	legacyArgs := append([]string{appCommand}, args[1:]...)
	return delegateLegacy(legacyArgs, errw)
}

// delegateLegacy runs a migrated nwn-tool command via internal/app and maps its
// (code, err) result onto the dispatcher's exit code. app writes its own output
// to os.Stdout/os.Stderr (the writers the entrypoints pass through), so only the
// returned error is surfaced here.
func delegateLegacy(args []string, errw io.Writer) int {
	code, err := app.Run(args)
	if err != nil {
		fmt.Fprintln(errw, err)
	}
	return code
}

const unwiredMsg = `crucible %[1]s: not wired yet.

The %[2]s builder has no migrated logic in this tree yet, so it fails closed
(exit 70) rather than producing a fake artifact. See docs/command-surface.md.
`

func usage(w io.Writer) {
	fmt.Fprintf(w, "crucible — Shadows Over Westgate build/conversion/sync toolchain\n")
	fmt.Fprintf(w, "%s\n\n", buildinfo.String())
	fmt.Fprintf(w, "usage:\n")
	fmt.Fprintf(w, "  crucible <builder> [args]    dispatch to a builder\n")
	fmt.Fprintf(w, "  crucible-<builder> [args]    equivalent standalone binary\n\n")
	fmt.Fprintf(w, "builders:\n")
	list(w)
	fmt.Fprintf(w, "\nglobal commands:\n")
	fmt.Fprintf(w, "  help | -h         show this help\n")
	fmt.Fprintf(w, "  version | -V      show the build version\n")
	fmt.Fprintf(w, "  list              list builders (one per line: name<TAB>bin<TAB>summary)\n")
	fmt.Fprintf(w, "  config [args]     inspect/validate effective configuration\n")
	fmt.Fprintf(w, "  changelog [args]  generate the release changelog\n")
	fmt.Fprintf(w, "\nBuilders read all inputs from the project tree (nwn-tool.yaml + data/); no\n")
	fmt.Fprintf(w, "NWN install is required. A builder that one day needs NWN game data\n")
	fmt.Fprintf(w, "auto-detects the install; it never requires a hand-set path. See\n")
	fmt.Fprintf(w, "docs/consumer-contract.md.\n")
}

func list(w io.Writer) {
	for _, b := range Registry {
		fmt.Fprintf(w, "%s\t%s\t%s\n", b.Name, b.Bin, b.Summary)
	}
}

func builderHelp(w io.Writer, b Builder) {
	fmt.Fprintf(w, "crucible %s (%s) — %s\n\n", b.Name, b.Bin, b.Summary)
	if !b.Wired {
		fmt.Fprintf(w, "status: not wired — no migrated logic yet; fails closed (exit 70).\n")
		fmt.Fprintf(w, "See docs/command-surface.md.\n")
		return
	}
	fmt.Fprintf(w, "usage: crucible %s <subcommand> [args]   (or: %s <subcommand> [args])\n\n", b.Name, b.Bin)
	fmt.Fprintf(w, "subcommands:\n")
	width := 0
	for _, command := range b.Commands {
		if len(command.Name) > width {
			width = len(command.Name)
		}
	}
	for _, command := range b.Commands {
		fmt.Fprintf(w, "  %-*s  %s\n", width, command.Name, command.Summary)
	}
	fmt.Fprintf(w, "\nstatus: wired to migrated nwn-tool logic. See docs/command-surface.md.\n")
}

func commandHelp(w io.Writer, command Command) {
	fmt.Fprintf(w, "%s\n", command.Summary)
	if command.Usage != "" {
		fmt.Fprintf(w, "\nusage: %s\n", command.Usage)
	}
	if len(command.Options) > 0 {
		fmt.Fprintln(w, "\noptions:")
		for _, option := range command.Options {
			fmt.Fprintf(w, "  %s\n", option)
		}
	}
}