// Package dispatch is the Crucible command surface: a single registry of
// builders shared by the `crucible` dispatcher and the standalone
// `crucible-<name>` shims.
//
// Scaffold contract (Phase 5): every builder is registered but UNWIRED. Running
// a builder fails closed (exit 70) with an operator-cutover message; it never
// fakes an artifact. The internal pipeline/topdata/erf/wiki/music packages from
// gitea/sow-tools are migrated by the operator at cutover (the workspace hard
// rules forbid transplanting source here). Once a builder's handler is wired,
// flip its Wired flag and register the handler.
package dispatch

import (
	"fmt"
	"io"
	"os"
	"text/tabwriter"

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

// 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
	Legacy  []string // nwn-tool commands this subsumes (migration aid; see docs/command-surface.md)
}

// 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)",
		Legacy:  nil,
	},
	{
		Name:    "hak",
		Bin:     "crucible-hak",
		Summary: "pack/unpack ERF/HAK archives + hak manifests",
		Legacy:  []string{"build-haks", "apply-hak-manifest"},
	},
	{
		Name:    "module",
		Bin:     "crucible-module",
		Summary: "build/extract/validate/compare the .mod",
		Legacy:  []string{"build", "build-module", "extract", "validate", "compare"},
	},
	{
		Name:    "topdata",
		Bin:     "crucible-topdata",
		Summary: "compile 2da/tlk topdata + packages",
		Legacy:  []string{"validate-topdata", "build-topdata", "build-top-package", "compare-topdata", "convert-topdata"},
	},
	{
		Name:    "wiki",
		Bin:     "crucible-wiki",
		Summary: "render + deploy mechanical wiki pages",
		Legacy:  []string{"build-wiki", "deploy-wiki"},
	},
}

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.
func Main(args []string) int { return run(args, os.Stdout, os.Stderr) }

// 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
	}
	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
		}
	}
	// Every builder is unwired in the Phase 5 scaffold: fail closed, never fake.
	fmt.Fprintf(errw, unwiredMsg, b.Name, b.Bin)
	return exitUnwired
}

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

The Crucible suite is scaffolded (Phase 5). The %[2]s implementation is migrated
from gitea/sow-tools internal packages at operator cutover; the workspace hard
rules forbid transplanting that source into this tree automatically.

This command fails closed (exit 70) rather than producing a fake artifact.
See docs/migration-from-nwn-tool.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, "\nNWN_ROOT must be passed explicitly (env or flag); crucible never guesses\n")
	fmt.Fprintf(w, "from $HOME. See docs/consumer-contract.md.\n")
}

func list(w io.Writer) {
	tw := tabwriter.NewWriter(w, 0, 2, 2, ' ', 0)
	for _, b := range Registry {
		fmt.Fprintf(tw, "  %s\t%s\t%s\n", b.Name, b.Bin, b.Summary)
	}
	tw.Flush()
}

func builderHelp(w io.Writer, b Builder) {
	fmt.Fprintf(w, "crucible %s (%s) — %s\n\n", b.Name, b.Bin, b.Summary)
	if len(b.Legacy) > 0 {
		fmt.Fprintf(w, "subsumes nwn-tool commands: ")
		for i, c := range b.Legacy {
			if i > 0 {
				fmt.Fprintf(w, ", ")
			}
			fmt.Fprintf(w, "%s", c)
		}
		fmt.Fprintf(w, "\n\n")
	}
	fmt.Fprintf(w, "status: scaffolded, not wired (Phase 5). See docs/command-surface.md.\n")
}