// =====================================================================
// dist.sx — the `dist` distribution CLI entry point (subplan 03, Slice 1).
//
// Wires the real process argv (via `std.cli`'s `os_args`) to subcommand
// handlers through `cli.parse`. The three groups/commands are dispatched
// to STUB handlers for now — they acknowledge and emit a known result; the
// real publish/promote/rollback logic lands in P3.4/P3.5.
//
//   dist ci publish
//   dist release promote
//   dist release rollback
//
// EXIT-CODE CONTRACT (sysexits, via std.cli): success ends with
// `exit_ok()` (EX_OK = 0); a no-command / unknown-or-missing
// group/command/flag ends with `exit_usage()` (EX_USAGE = 64). An
// explicit `-h`/`--help` is not an error and ends 0.
//
// `--json` PURITY: every command accepts the reserved global `--json`
// flag (surfaced by the parser as `parsed.json`). In json mode stdout
// carries ONLY the machine-readable JSON object (emitted via `std.json`,
// isolated in `json_out.sx`); ALL human-readable text (help, progress,
// errors) goes to stderr. In non-json mode human text on stdout is fine.
// =====================================================================

#import "modules/std.sx";
#import "modules/std/cli.sx";
jout :: #import "json_out.sx";

// Direct stderr writer (fd 2), so human help/usage/progress never lands on
// stdout's data stream. `out` (std builtin) targets stdout (fd 1).
cstdlib  :: #library "c";
fd_write :: (fd: s32, buf: [*]u8, count: usize) -> isize #foreign cstdlib "write";

eputs :: (s: string) { if s.len > 0 { fd_write(2, s.ptr, xx s.len); } }

// Human text router: stderr in json mode (keep stdout pure), stdout
// otherwise.
emit_human :: (s: string, json_mode: bool) {
    if json_mode { eputs(s); } else { out(s); }
}

HELP :: "dist — application distribution CLI\n\nUsage:\n  dist <group> <command> [flags]\n\nGroups & commands:\n  ci\n    ci publish            publish a release from CI (stub)\n  release\n    release promote       promote a release onto a channel (stub)\n    release rollback      roll a channel back to a prior release (stub)\n\nGlobal flags:\n  --json                  emit machine-readable JSON on stdout; human text to stderr\n  -h, --help              show this help and exit\n\nExit codes:\n  0   success\n  64  usage error (no command, or an unknown/missing command or flag)\n";

// True if `name` appears as a token in `args`.
has_flag :: (args: []string, name: string) -> bool {
    i := 0;
    while i < args.len {
        if args[i] == name { return true; }
        i += 1;
    }
    return false;
}

// Human phrase for a parser failure, used in the stderr diagnostic.
error_phrase :: (e: CliError) -> string {
    if e == error.UnknownCommand  { return "unknown or missing command"; }
    if e == error.UnknownFlag     { return "unknown flag"; }
    if e == error.MissingValue    { return "flag is missing its value"; }
    if e == error.MissingRequired { return "missing required flag"; }
    if e == error.TooManyFlags    { return "too many flags for command"; }
    return "usage error";
}

// ── Stub handlers ────────────────────────────────────────────────────
// Honest stubs: acknowledge the command and emit a known result. NO real
// publish/promote/rollback logic (that is P3.4/P3.5).

handle_ci_publish :: (p: *Parsed, json_mode: bool) {
    ack("ci publish", json_mode);
}
handle_release_promote :: (p: *Parsed, json_mode: bool) {
    ack("release promote", json_mode);
}
handle_release_rollback :: (p: *Parsed, json_mode: bool) {
    ack("release rollback", json_mode);
}

// Emit a stub command's acknowledgement. In json mode: a single JSON
// object on stdout (and a human progress note on stderr). Otherwise: a
// human acknowledgement on stdout.
ack :: (cmd: string, json_mode: bool) {
    if !json_mode {
        out(concat(concat("dist: ", cmd), " (stub) ok\n"));
        return;
    }

    eputs(concat(concat("dist: ", cmd), " (stub) acknowledged\n"));

    raw : [4096]u8 = ---;
    werr := false;
    n := jout.write_stub(cmd, string.{ ptr = @raw[0], len = 4096 }) catch { werr = true; 0 };
    if werr {
        eputs("dist: internal error: JSON serialization failed\n");
        exit_usage();
    }
    out(string.{ ptr = @raw[0], len = n });
    out("\n");
}

// Route a parsed (group, command) to its stub handler. `parse` only
// returns a (group, command) present in the table, so one arm always
// matches.
dispatch :: (p: *Parsed, json_mode: bool) {
    if p.group == "ci"      and p.command == "publish"  { handle_ci_publish(p, json_mode);      return; }
    if p.group == "release" and p.command == "promote"  { handle_release_promote(p, json_mode); return; }
    if p.group == "release" and p.command == "rollback" { handle_release_rollback(p, json_mode); return; }
    eputs("dist: internal error: unrouted command\n");
    exit_usage();
}

main :: () -> ! {
    // Real process argv -> logical args: drop argv[0] (the program path).
    storage : [64]string = ---;
    argbuf : []string = ---;
    argbuf.ptr = @storage[0];
    argbuf.len = 64;
    argv := os_args(argbuf);
    args : []string = if argv.len <= 1 then argv[argv.len ..] else argv[1 ..];

    json_mode := has_flag(args, "--json");

    if has_flag(args, "-h") or has_flag(args, "--help") {
        emit_human(HELP, json_mode);
        exit_ok();
    }

    if args.len == 0 {
        eputs("dist: no command given\n\n");
        eputs(HELP);
        exit_usage();
    }

    // Command table + flag specs live in this scope; `Parsed` holds VIEWS
    // into them, used before `main` returns. Per-command flags arrive with
    // the real handlers in P3.4/P3.5 — the global `--json` is recognized by
    // the parser without being declared here.
    no_flags : []FlagSpec = .[];
    cmds : []Command = .[
        Command.{ group = "ci",      command = "publish",  flags = no_flags },
        Command.{ group = "release", command = "promote",  flags = no_flags },
        Command.{ group = "release", command = "rollback", flags = no_flags },
    ];

    diag : Diag = .{};
    p, perr := parse(args, cmds, @diag);
    if perr {
        eputs(concat(concat(concat("dist: ", error_phrase(perr)), ": "), diag.token));
        eputs("\n\n");
        eputs(HELP);
        exit_usage();
    }

    if !perr {
        dispatch(@p, json_mode);
    }
    exit_ok();
}