9 files changed, 859 insertions, 0 deletions
diff --git a/src/xpit_/args_helpers.py b/src/xpit_/args_helpers.py
new file mode 100644
index 0000000..1e79911
--- /dev/null
+++ b/src/xpit_/args_helpers.py
@@ -0,0 +1,102 @@
+from sys import stderr
+from . import error
+Err = error.Err
+
+def print_error(msg: str) -> None:
+    stderr.write(f"{msg}\n")
+
+def err_arg_unrecognized(arg: str) -> None:
+    print_error(f"Unrecognized argument: {arg}")
+
+ERR_UNRECOGNIZED_ARG = "ERR_UNRECOGNIZED_ARG"
+ERR_NOT_ENOUGH_ARGS = "ERR_NOT_ENOUGH_ARGS"
+
+def parse_arg(
+    argv: list[str],
+    i: int,
+    flag_value_map: dict[str, int]
+) -> tuple[str, list[str], int, Err | None]:
+    def success(
+        flag: str,
+        values: list[str],
+        new_i: int
+    ) -> tuple[str, list[str], int, Err | None]:
+        return flag, values, new_i, None
+    def fail(msg: str) -> tuple[str, list[str], int, Err | None]:
+        return "", [], 0, Err(msg)
+
+    flag: str
+    values: list[str] = []
+    arg: str = argv[i]
+    i += 1
+    if arg[0] != '-':
+        err_arg_unrecognized(arg)
+        return fail(ERR_UNRECOGNIZED_ARG)
+
+    value_index = 0
+    if arg[1] == '-':
+        # --flag
+        delimiter_index = arg.find('=')
+        if delimiter_index == -1:
+            flag = arg[2:]
+            value_index = 0
+        else:
+            flag = arg[2:delimiter_index]
+            values.append(arg[delimiter_index+1:])
+            value_index = 1
+
+    else:
+        # -f
+        flag = arg[1]
+        value_index = 0
+
+        if len(arg) != 2:
+            value = arg[2:]
+            if value[0] == '=':
+                value = value[1:]
+            values.append(value)
+            value_index += 1
+    target_flag_set_arr = None
+    value_count: int = 0
+    for flag_set in flag_value_map:
+        flag_set_arr = flag_set.split('|')
+        if flag in flag_set_arr:
+            target_flag_set_arr = flag_set_arr
+            value_count = flag_value_map[flag_set]
+            break
+    if target_flag_set_arr is None:
+        err_arg_unrecognized(flag)
+        return fail(ERR_UNRECOGNIZED_ARG)
+    while value_index < value_count:
+        if i >= len(argv):
+            print_error(f"Not enough arguments for flag '{flag}'")
+            return fail(ERR_NOT_ENOUGH_ARGS)
+        values.append(argv[i])
+        i += 1
+        value_index += 1
+
+    # NOTE: we always return the first flag in the flag-set for normalization
+    return success(target_flag_set_arr[0], values, i)
+
+def parse_generic(
+    flag_value_map: dict[str, int],
+    argv: list[str],
+    i: int
+) -> dict[str, list[str]] | None:
+    res: dict[str, list[str]] = {}
+    while i < len(argv):
+        arg = argv[i]
+        if len(arg) >= 2:
+            flag, values, i, err = parse_arg(argv, i, flag_value_map)
+            if err is not None:
+                return None
+
+            res[flag] = values
+            #if not callback(flag, values):
+            #    return False
+        else:
+            err_arg_unrecognized(arg)
+            return None
+
+    return res
+
diff --git a/src/xpit_/create.py b/src/xpit_/create.py
new file mode 100644
index 0000000..30d32fa
--- /dev/null
+++ b/src/xpit_/create.py
@@ -0,0 +1,263 @@
+import os
+import subprocess
+import getpass
+from sys import argv, stdout, stderr
+from datetime import datetime, timezone
+from . import args_helpers, identity, issue, issue_tracker
+
+help_text = """\
+Usage: xpit create [options]
+Examples:
+    xpit create
+    xpit create -u Bob -i secret_bob_alias -r 20260101_120000:20260101_140000 -x
+    xpit create -e_ -t "Startup slow" -l performance,startup -d "The window takes 200ms to open."
+Options:
+    -d, --description <str>
+        The post body.
+        Defaults to 'Description goes here...'
+    -x, --disable-inline-annotations
+        Disable the explanatory ; annotations in newly created posts' headers.
+    -e, --editor <str>
+        Which editor to open the issue in.
+        Pass '_' (underscore) to not open an editor.
+        If not specified, the editor is chosen in the following order:
+            1. $XPIT_EDITOR
+            2. $GIT_EDITOR
+            3. $EDITOR
+            4. $VISUAL
+            5.
+                windows: "notepad"
+                other: "vi"
+    -i, --identity <str>
+        Label for keypair used for unique identification and signature.
+        This is used to uniquely identify a user.
+        Keys are stored in '~/.config/xpit/identities/'.
+        Defaults to 'default'.
+    -l, --labels <str>
+        Comma-separated list of labels applicable to this issue.
+        Not compatible with --reply-to.
+        Empty by default.
+    -r, --reply-to <ISSUE_ID>[:LOCAL_ID]
+        Reply to an issue or a specific reply within an issue.
+    -P, --skip-prompt
+        Skip interactive prompts for missing fields (title, description, labels).
+        Only applies when using `-e_` (no automatic editor).
+    -t, --title <str>
+        The issue's title.
+        Not compatible with --reply-to.
+        Defaults to 'Title'.
+    -u, --username <str>
+        The username to use for the issue.
+        If not specified, uses `getpass.getuser()`.
+    -h, --help
+        Print this help text.
+"""
+
+class Args:
+    def __init__(self):
+        self.config_dir: str
+        self.editor: str
+        self.username: str
+        self.identity: str = "default"
+        self.reply_to: str | None = None
+        self.disable_inline_annotations: bool = False
+
+        self.labels: bytes = b""
+        self.skip_prompt: bool = False
+        self.description: bytes = b"Description goes here..."
+        self.title: bytes = b"Title"
+
+    def parse(self) -> bool:
+        flag_value_map = {
+            "help|h": 0,
+            "description|d": 1,
+            "disable-inline-annotations|x": 0,
+            "editor|e": 1,
+            "identity|i": 1,
+            "labels|l": 1,
+            "reply|r": 1,
+            "skip-prompt|P": 0,
+            "title|t|": 1,
+            "username|u": 1,
+        }
+        res = args_helpers.parse_generic(flag_value_map, argv, 2)
+        _editor: str | None = None
+        _username: str | None = getpass.getuser()
+        if res is None:
+            return False
+        if "help" in res:
+            stdout.write(help_text)
+            return False
+        if "description" in res:
+            self.description = res["description"][0].encode("utf-8")
+        if "disable-inline-annotations" in res:
+            self.disable_inline_annotations = True
+        if "editor" in res:
+            _editor = res["editor"][0]
+        if "identity" in res:
+            self.identity = res["identity"][0]
+        if "labels" in res:
+            labels: str = res["labels"][0]
+            issue_tracker.load_config()
+            for label in labels.split(','):
+                if label.encode("utf-8") not in issue_tracker.config[b"allowed_labels"]:
+                    stderr.write(
+                        f"Label '{label}' not allowed.\nAllowed: "
+                        +issue_tracker.config[b"allowed_labels"].decode("utf-8")
+                        +'\n')
+                    return False
+            self.labels = labels.encode("utf-8")
+        if "reply" in res:
+            self.reply_to = res["reply"][0]
+        if "skip-prompt" in res:
+            self.skip_prompt = True
+        if "title" in res:
+            self.title = res["title"][0].encode("utf-8")
+        if "username" in res:
+            _username = res["username"][0]
+
+        if _username is None:
+            stderr.write("No username.")
+            return False
+        self.username = _username
+
+        if _editor is None:
+            _editor = (
+                   os.environ.get("XPIT_EDITOR")
+                or os.environ.get("GIT_EDITOR")
+                or os.environ.get("EDITOR")
+                or os.environ.get("VISUAL")
+                or None
+            )
+        if _editor is None:
+            if os.name == "nt":
+                _editor = "notepad"
+            else:
+                _editor = "vi"
+        self.editor = _editor
+
+        if os.name == "nt":
+            appdata = os.getenv("APPDATA")
+            if appdata is None:
+                stderr.write("Couldn't find $APPDATA directory")
+                return False
+            self.config_dir = os.path.join(appdata, "xpit")
+        else:
+            home = os.getenv("HOME")
+            if home is None:
+                stderr.write("Couldn't find $HOME directory")
+                return False
+            self.config_dir = os.path.join(home, ".config", "xpit")
+
+        return True
+args = Args()
+
+def id_gen() -> str:
+    return datetime.now(timezone.utc).strftime(issue_tracker.config[b"id_format"].decode("utf-8"))
+
+def main() -> int:
+    if len(argv) < 2:
+        stdout.write(help_text)
+        return 1
+
+    if not args.parse():
+        return 1
+
+    identities_dir = os.path.join(args.config_dir, "identities")
+    private_key, public_key = identity.load(identities_dir, args.identity)
+    _ = private_key
+
+    issue_tracker.load_config()
+    if issue_tracker.dir is None:
+        stderr.write("xpit not initialized. Run `xpit init`.\n")
+        return 1
+
+    if args.reply_to is None:
+        issue_id = id_gen()
+    else:
+        issue_id = args.reply_to.split(":", 1)[0]
+    issue_dir = os.path.join(issue_tracker.dir, issue_id)
+    if args.reply_to is None:
+        if os.path.exists(issue_dir):
+            stderr.write(f"Failed to create issue {issue_id}: Already exists.\n")
+            return 1
+        os.mkdir(issue_dir)
+
+    issue_tracker_path = os.path.join(issue_dir, "issue.md")
+    if args.reply_to is not None:
+        if not os.path.isfile(issue_tracker_path):
+            stderr.write(f"Issue {issue_id} not found.\n")
+            return 1
+        with open(issue_tracker_path, "r+b") as f:
+            src = f.read()
+            info, err = issue.parse(src)
+            if err is not None:
+                stderr.write(err.msg)
+                return 1
+            if info.meta[b"status"] != b"open":
+                stderr.write(f"Issue {issue_id} already closed.\n")
+                return 1
+
+    identity_id = identity.id_from_pubkey(public_key)
+    # help_author = b" ; your user-ID"
+    # help_status = b" ; open | closed"
+    allowed_labels = issue_tracker.config[b"allowed_labels"]
+    help_labels = b" ; comma-separated list. Allowed labels are: "+allowed_labels
+    # help_id =     b" ; this reply's local ID"
+    # help_reply =  b" ; local ID of the post you're replying to"
+    if args.disable_inline_annotations:
+        help_labels = b""
+    if args.editor == "_" and not args.skip_prompt:
+        if args.title is None:
+            args.title = input("Title: ").encode("utf-8")
+        if args.labels is None:
+            args.labels = input("Labels (Comma-separated): ").encode("utf-8")
+        if args.description is None:
+            args.description = input("Description: ").encode("utf-8")
+    with open(issue_tracker_path, "ab") as f:
+        ini_author = b"author=" + args.username.encode("utf-8") + b'#' + identity_id + b'\n'
+        if args.reply_to is None:
+            ini_status = b"status=open\n"
+            ini_labels = b"labels="+args.labels + help_labels + b'\n'
+            ini_add_after_edit = ini_author + ini_status
+            ini_add_now = ini_labels
+            if args.editor == "_":
+                ini_add_now = ini_add_after_edit + ini_add_now
+            msg = b"```ini\n"+ini_add_now+b"""```
+
+# """+args.title+b"""
+
+"""+args.description+b"""
+
+"""
+        else:
+            ini_id = b"id="+id_gen().encode("utf-8")+b'\n'
+            reply_to = args.reply_to.split(":", 2)
+            ini_reply = b""
+            if len(reply_to) == 2:
+                ini_reply = b"reply="+reply_to[1].encode("utf-8")+b'\n'
+            ini_add_after_edit = ini_author + ini_id
+            ini_add_now = ini_reply
+            if args.editor == "_":
+                ini_add_now = ini_add_after_edit + ini_add_now
+            msg = b"---\n```ini\n"+ini_add_now+b"```\n\n"+args.description+b"\n\n"
+        f.write(msg)
+
+    if args.editor != "_":
+        subprocess.call([args.editor, issue_tracker_path])
+        with open(issue_tracker_path, "r+b") as f:
+            src = f.read()
+            src = issue.clean_after_edit(src, ini_add_after_edit)
+            f.seek(0)
+            f.write(src)
+            f.truncate()
+            # TODO check if labels ok. Maybe we want to have some sort of `check` command
+
+    relpath = os.path.relpath(issue_tracker_path, os.getcwd())
+    if args.reply_to is None:
+        stdout.write(f"Created new issue ./{relpath}\n")
+    else:
+        stdout.write(f"Replied to {args.reply_to}\n")
+
+    return 0
+
diff --git a/src/xpit_/error.py b/src/xpit_/error.py
new file mode 100644
index 0000000..12cf084
--- /dev/null
+++ b/src/xpit_/error.py
@@ -0,0 +1,4 @@
+class Err:
+    def __init__(self, msg: str):
+        self.msg = msg
+
diff --git a/src/xpit_/identity.py b/src/xpit_/identity.py
new file mode 100644
index 0000000..2786b2d
--- /dev/null
+++ b/src/xpit_/identity.py
@@ -0,0 +1,59 @@
+import os
+import base64
+from sys import stdout
+from cryptography.hazmat.primitives import serialization
+from cryptography.hazmat.primitives.asymmetric import ed25519
+from cryptography.hazmat.primitives.asymmetric.types import PrivateKeyTypes, PublicKeyTypes
+
+# TODO guard against bad file access
+def create(path: str) -> None:
+    private_key = ed25519.Ed25519PrivateKey.generate()
+    public_key = private_key.public_key()
+    enc = serialization.NoEncryption()
+
+    os.mkdir(path)
+
+    data = private_key.private_bytes(
+        encoding=serialization.Encoding.PEM,
+        format=serialization.PrivateFormat.PKCS8,
+        encryption_algorithm=enc,
+    )
+    with open(os.path.join(path, "private.pem"), "wb") as f:
+        f.write(data)
+
+    data = public_key.public_bytes(
+        encoding=serialization.Encoding.PEM,
+        format=serialization.PublicFormat.SubjectPublicKeyInfo,
+    )
+    with open(os.path.join(path, "public.pub"), "wb") as f:
+        f.write(data)
+
+def load(identities_dir: str, identity: str) -> tuple[PrivateKeyTypes, PublicKeyTypes]:
+    if not os.path.isdir(identities_dir):
+        os.makedirs(identities_dir)
+
+    path = os.path.join(identities_dir, identity)
+
+    if not os.path.isdir(path):
+        stdout.write(f"Generating new identity '{identity}'...\n")
+        create(path)
+        stdout.write(f"Created new identity '{identity}' at: {path}\n")
+
+    with open(os.path.join(path, "private.pem"), "rb") as f:
+        private_key_data = f.read()
+    with open(os.path.join(path, "public.pub"), "rb") as f:
+        public_key_data = f.read()
+
+    return (
+        serialization.load_pem_private_key(private_key_data, password=None),
+        serialization.load_pem_public_key(public_key_data)
+    )
+
+def id_from_pubkey(pubkey: PublicKeyTypes) -> bytes:
+    der = pubkey.public_bytes(
+        encoding=serialization.Encoding.DER,
+        format=serialization.PublicFormat.SubjectPublicKeyInfo,
+    )
+    b64 = base64.b64encode(der)
+    return b64[16:24]
+
diff --git a/src/xpit_/init.py b/src/xpit_/init.py
new file mode 100644
index 0000000..3663f4f
--- /dev/null
+++ b/src/xpit_/init.py
@@ -0,0 +1,54 @@
+import os
+from sys import argv, stdout, stderr
+from . import args_helpers, issue_tracker
+
+help_text = """\
+Usage: xpit init
+Options:
+    -h, --help
+        Print this help text.
+"""
+
+class Args:
+    def __init__(self):
+        pass
+
+    def parse(self) -> bool:
+        flag_value_map = {
+            "help|h": 0,
+        }
+        res = args_helpers.parse_generic(flag_value_map, argv, 2)
+        if res is None:
+            return False
+        if "help" in res:
+            stdout.write(help_text)
+            return False
+
+        return True
+args = Args()
+
+def main() -> int:
+    if len(argv) < 2:
+        stdout.write(help_text)
+        return 1
+
+    if not args.parse():
+        return 1
+
+    if issue_tracker.find_dir(os.getcwd(), suppress_warning=True) is not None:
+        stderr.write("xpit already initialized\n")
+        return 1
+    os.mkdir("issue-tracker")
+    config_file_path = os.path.join("issue-tracker", "_config.ini")
+    with open(config_file_path, "wb") as f:
+        f.write(b"""\
+id_format=%Y%m%d_%H%M%S ; `man strftime` for format
+allowed_labels=bug,breaking,contributor-friendly,docs,use-case,regression,proposal ; labels that are allowed to be used in issues. (Comma-separated list)
+\n""")
+    stdout.write(f"""\
+Successfully initialized at ./issue-tracker.
+Configure in {config_file_path}
+""")
+
+    return 0
+
diff --git a/src/xpit_/issue.py b/src/xpit_/issue.py
new file mode 100644
index 0000000..53efeef
--- /dev/null
+++ b/src/xpit_/issue.py
@@ -0,0 +1,168 @@
+from __future__ import annotations
+from . import error
+Err = error.Err
+
+class Post:
+    def __init__(self):
+        self.meta: dict[bytes, bytes] = {}
+        self.title: bytes = b""
+        self.replies: list[Post] = []
+
+    def reply_get(self, needle: bytes) -> Post | None:
+        for reply in self.replies:
+            if b"id" not in reply.meta:
+                continue
+            if reply.meta[b"id"] == needle:
+                return reply
+            res = reply.reply_get(needle)
+            if res is not None:
+                return res
+        return None
+
+    def post_count(self) -> int:
+        count = 1
+        for reply in self.replies:
+            count += reply.post_count()
+        return count
+
+def is_newline(c: int) -> bool:
+    return (
+           c == ord('\n')
+        or c == ord('\r')
+    )
+
+def is_whitespace(c: int) -> bool:
+    return (
+           c == ord(' ')
+        or c == ord('\t')
+        or is_newline(c)
+    )
+
+def parse_ini(src: bytes | memoryview, i: int, res: dict[bytes, bytes]) -> int:
+    src = memoryview(src)
+
+    STATE_START = 0
+    STATE_KEY = 1
+    STATE_VALUE = 2
+    state = STATE_START
+
+    key = bytearray()
+    value = bytearray()
+
+    while i < len(src):
+        if state == STATE_START:
+            if src[i:i+4] == b"```\n":
+                return i + 4
+            elif src[i] == ord(' '):
+                pass
+            else:
+                state = STATE_KEY
+                continue
+        elif state == STATE_KEY:
+            if src[i] == ord('='):
+                state = STATE_VALUE
+            else:
+                key.append(src[i])
+        elif state == STATE_VALUE:
+            if is_newline(src[i]) or src[i] == ord(';'):
+                if src[i] == ord(';'):
+                    while len(value) > 0 and is_whitespace(value[-1]):
+                        value.pop()
+                    while i < len(src) and not is_newline(src[i]):
+                        i += 1
+                res[bytes(key)] = bytes(value)
+                state = STATE_START
+                key.clear()
+                value.clear()
+            else:
+                value.append(src[i])
+        else:
+            assert False, "unreachable: state enum not exhausted"
+
+        i += 1
+
+    return -1
+
+def parse(src: bytes | memoryview) -> tuple[Post, Err | None]:
+    def success(post: Post) -> tuple[Post, Err | None]:
+        return post, None
+    def fail(msg: str) -> tuple[Post, Err | None]:
+        return Post(), Err(msg)
+
+    src = memoryview(src)
+    issue = Post()
+    issue_title: bytes | None = None
+    i = 0
+
+    post = issue
+    while i < len(src):
+        if src[i:i+4] == b"\n---":
+            i += 4
+            post = Post()
+            continue
+        if src[i:i+7] == b"```ini\n":
+            i += 7
+            i = parse_ini(src, i, post.meta)
+            if i == -1:
+                return fail("ERR_FAILED_TO_PARSE_INI")
+            if b"reply" in post.meta:
+                reply = issue.reply_get(post.meta[b"reply"])
+                if reply is None:
+                    return fail("ERR_REPLY_TO_NONEXISTENT_ID")
+                reply.replies.append(post)
+            elif post != issue:
+                issue.replies.append(post)
+            continue
+        if issue_title is None and src[i:i+2] == b"# ":
+            i += 2
+            title_start = i
+            while i < len(src):
+                if is_newline(src[i]):
+                    break
+                i += 1
+            issue_title = bytes(src[title_start:i])
+            continue
+
+        i += 1
+
+    if issue_title is None:
+        return fail("ERR_ISSUE_NO_TITLE")
+    issue.title = issue_title
+
+    return success(issue)
+
+def clean_after_edit(src: bytes | memoryview, last_ini_prefix: bytes) -> bytes:
+    src = memoryview(src)
+    last_ini_prefix = bytes(last_ini_prefix)
+    res: list[int] = []
+    i = 0
+    last_ini_start = 0
+    while i < len(src):
+        while i < len(src):
+            if src[i:i+7] == b"```ini\n":
+                res.extend(src[i:i+7])
+                last_ini_start = len(res)
+                i += 7
+                break
+            res.append(src[i])
+            i += 1
+
+        while i < len(src):
+            # inside ini
+            if src[i:i+4] == b"\n```":
+                res.extend(src[i:i+4])
+                i += 4
+                break
+            elif src[i:i+3] == b" ; ":
+                i += 3
+                while i < len(src):
+                    if is_newline(src[i]):
+                        break
+                    i += 1
+            res.append(src[i])
+            i += 1
+
+    res[last_ini_start:last_ini_start] = last_ini_prefix
+
+    return bytes(res)
+
diff --git a/src/xpit_/issue_tracker.py b/src/xpit_/issue_tracker.py
new file mode 100644
index 0000000..20c1662
--- /dev/null
+++ b/src/xpit_/issue_tracker.py
@@ -0,0 +1,52 @@
+import os
+import sys
+from . import issue
+from . import error
+Err = error.Err
+
+class State:
+    def __init__(self):
+        self.dir: str | None = None
+        self.config: dict[bytes, bytes] | None = None
+        self.allowed_labels: list[bytes] | None = None
+state = State()
+
+def find_dir(start_dir: str, suppress_warning: bool = False) -> str | None:
+    cur = os.path.abspath(start_dir)
+
+    while True:
+        candidate = os.path.join(cur, "issue-tracker")
+        if os.path.isdir(candidate):
+            return candidate
+
+        parent = os.path.dirname(cur)
+        if parent == cur:  # reached filesystem root
+            if not suppress_warning:
+                sys.stderr.write(
+                    "xpit has not been initialized. `xpit init` to initialize.\n"
+                )
+            return None
+        cur = parent
+
+def load_config() -> Err | None:
+    if state.dir is None:
+        state.dir = find_dir(os.getcwd())
+    if state.dir is None:
+        return Err("ERR_COULD_NOT_FIND_ISSUE_TRACKER_DIR")
+    with open(os.path.join(state.dir, "_config.ini"), "rb") as f:
+        src = f.read()
+    state.config = {}
+    issue.parse_ini(src, 0, state.config)
+    if b"allowed_labels" not in state.config:
+        sys.stdout.write("Warning: _config.ini has no allowed_labels\n")
+        state.config[b"allowed_labels"] = b""
+    if b"id_format" not in state.config:
+        sys.stdout.write("Warning: _config.ini has no id_format. Defaulting to '%Y%m%d_%H%M%S'\n")
+        state.config[b"id_format"] = b"%Y%m%d_%H%M%S"
+    state.allowed_labels = state.config[b"allowed_labels"].split(b',')
+
+    return None
+
+def __getattr__(name):
+    return getattr(state, name)
+
diff --git a/src/xpit_/list_.py b/src/xpit_/list_.py
new file mode 100644
index 0000000..fe281c2
--- /dev/null
+++ b/src/xpit_/list_.py
@@ -0,0 +1,104 @@
+import os
+from sys import argv, stdout, stderr
+from . import args_helpers, issue, issue_tracker
+
+DEFAULT_ORDER: list[bytes] = [b"ID", b"POST_COUNT", b"TITLE", b"status", b"labels"]
+
+help_text = f"""\
+Usage: xpit list [options]
+Examples:
+    xpit list -d , -f TITLE,POST_COUNT
+Options:
+    -d, --delimiter <str>
+        Delimiter used to separate the fields.
+        Defaults to '|' (pipe).
+    -f, --fields <FIELD,...>
+        Defaults to '{b','.join(DEFAULT_ORDER).decode("utf-8")}'.
+        Guaranteed fields:
+            ID - ID of the issue
+            TITLE - Title of the issue
+            AUTHOR - Author of the issue
+            POST_COUNT - Total number of posts in the issue, including the initial post
+            PATH_ABS - absolute path to issue.md file
+            PATH_REL - relative path to issue.md file
+        Other fields are optional and parsed in issues' INI headers.
+        The fields are printed in order and the same field can be printed more than once.
+    -h, --help
+        Print this help text.
+"""
+
+class Args:
+    def __init__(self) -> None:
+        self.order = DEFAULT_ORDER
+        self.delimiter = '|'
+
+    def parse(self) -> bool:
+        flag_value_map = {
+            "help|h": 0,
+            "delimiter|d": 1,
+            "fields|f": 1,
+        }
+        res = args_helpers.parse_generic(flag_value_map, argv, 2)
+        if res is None:
+            return False
+        if "help" in res:
+            stdout.write(help_text)
+            return False
+        if "delimiter" in res:
+            self.delimiter = res["delimiter"][0]
+        if "fields" in res:
+            self.order = [field.encode("utf-8") for field in res["fields"][0].split(',')]
+
+        return True
+args = Args()
+
+def main() -> int:
+    if len(argv) < 2:
+        stdout.write(help_text)
+        return 1
+
+    if not args.parse():
+        return 1
+
+    cwd = os.getcwd()
+    issue_tracker_dir = issue_tracker.find_dir(cwd)
+    if issue_tracker_dir is None:
+        return 1
+    for file_name in os.listdir(issue_tracker_dir):
+        if not os.path.isdir(os.path.join(issue_tracker_dir, file_name)):
+            continue
+
+        file_path = os.path.join(issue_tracker_dir, file_name, "issue.md")
+        with open(file_path, "rb") as f:
+            src = f.read()
+        info, err = issue.parse(src)
+        if err is not None:
+            stderr.write(err.msg)
+            return 1
+        i = 0
+        while True:
+            key = args.order[i]
+            if key == b"ID":
+                stdout.write(file_name)
+            elif key == b"TITLE":
+                stdout.write(info.title.decode("utf-8"))
+            elif key == b"POST_COUNT":
+                stdout.write(str(info.post_count()))
+            elif key == b"AUTHOR":
+                stdout.write(info.meta[b"author"].decode("utf-8"))
+            elif key == b"PATH_ABS":
+                stdout.write(file_path)
+            elif key == b"PATH_REL":
+                stdout.write(os.path.relpath(file_path, start=cwd))
+            else:
+                if key in info.meta:
+                    stdout.write(info.meta[key].decode("utf-8"))
+
+            i += 1
+            if i >= len(args.order):
+                break
+            stdout.write(args.delimiter)
+        stdout.write('\n')
+
+    return 0
+
diff --git a/src/xpit_/xpit.py b/src/xpit_/xpit.py
new file mode 100644
index 0000000..f6eefd0
--- /dev/null
+++ b/src/xpit_/xpit.py
@@ -0,0 +1,53 @@
+from sys import argv, stdout
+from . import args_helpers, init, create, list_
+
+help_text = """\
+xpit - cross-platform issue tracker
+Usage: xpit <COMMAND> [options]
+<COMMAND>:
+    init:
+        Initialize issue tracker in current directory.
+    create:
+        Create new issue or reply.
+    list:
+        List issues.
+Options:
+    -h, --help
+        Print this help text. `xpit <COMMAND> -h` for help with specific command.
+"""
+
+class Args:
+    def __init__(self) -> None:
+        pass
+
+    def parse(self) -> bool:
+        flag_value_map = {
+            "help|h": 0,
+        }
+        res = args_helpers.parse_generic(flag_value_map, argv, 1)
+        if res is None:
+            return False
+        if "help" in res:
+            stdout.write(help_text)
+            return False
+
+        return True
+args = Args()
+
+def main() -> int:
+    if len(argv) <= 1:
+        stdout.write(help_text)
+        return 1
+
+    elif argv[1] == "init":
+        return init.main()
+    elif argv[1] == "create":
+        return create.main()
+    elif argv[1] == "list":
+        return list_.main()
+    else:
+        if not args.parse():
+            return 1
+
+    return 0
+