#!/usr/bin/env python3
"""Compiles every languages/*.po into a binary .mo (no gettext tools required).

Usage: python3 bin/compile-mo.py
"""
import ast
import glob
import os
import struct

ROOT = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))


def parse_po(path):
    messages = {}
    ctx = msgid = msgstr = None
    plural = None
    plurals = {}
    section = None

    def flush():
        if msgid is None:
            return
        key = msgid if ctx is None else ctx + "\x04" + msgid
        if plural is not None:
            key = key + "\x00" + plural
            value = "\x00".join(plurals[i] for i in sorted(plurals))
        else:
            value = msgstr or ""
        if msgid == "" or value:
            messages[key] = value

    for raw in open(path, encoding="utf-8"):
        line = raw.strip()
        if not line or line.startswith("#"):
            continue
        if line.startswith("msgctxt "):
            flush()
            ctx, msgid, msgstr, plural, plurals = ast.literal_eval(line[8:]), None, None, None, {}
            section = "ctx"
        elif line.startswith("msgid_plural "):
            plural = ast.literal_eval(line[13:])
            section = "plural"
        elif line.startswith("msgid "):
            if section != "ctx":
                flush()
                ctx, msgstr, plural, plurals = None, None, None, {}
            msgid = ast.literal_eval(line[6:])
            section = "id"
        elif line.startswith("msgstr["):
            idx = int(line[7:line.index("]")])
            plurals[idx] = ast.literal_eval(line[line.index("]") + 1:].strip())
            section = ("pl", idx)
        elif line.startswith("msgstr "):
            msgstr = ast.literal_eval(line[7:])
            section = "str"
        elif line.startswith('"'):
            chunk = ast.literal_eval(line)
            if section == "ctx":
                ctx += chunk
            elif section == "id":
                msgid += chunk
            elif section == "plural":
                plural += chunk
            elif section == "str":
                msgstr += chunk
            elif isinstance(section, tuple):
                plurals[section[1]] += chunk
    flush()
    return messages


def write_mo(messages, path):
    keys = sorted(messages)
    ids = b""
    strs = b""
    offsets = []
    for k in keys:
        kb = k.encode("utf-8")
        vb = messages[k].encode("utf-8")
        offsets.append((len(ids), len(kb), len(strs), len(vb)))
        ids += kb + b"\x00"
        strs += vb + b"\x00"
    n = len(keys)
    keystart = 7 * 4 + 16 * n
    valuestart = keystart + len(ids)
    koffsets = []
    voffsets = []
    for o1, l1, o2, l2 in offsets:
        koffsets += [l1, o1 + keystart]
        voffsets += [l2, o2 + valuestart]
    output = struct.pack("Iiiiiii", 0x950412DE, 0, n, 7 * 4, 7 * 4 + n * 8, 0, 0)
    output += struct.pack("%di" % len(koffsets), *koffsets)
    output += struct.pack("%di" % len(voffsets), *voffsets)
    output += ids + strs
    open(path, "wb").write(output)


for po in sorted(glob.glob(os.path.join(ROOT, "languages", "*.po"))):
    mo = po[:-3] + ".mo"
    messages = parse_po(po)
    write_mo(messages, mo)
    print("Compiled %s (%d entries)" % (os.path.relpath(mo, ROOT), len(messages) - 1))