#!/usr/bin/env python3
import sys
import re
import ast


if len(sys.argv) != 3:
    print("Usage: sanitize_po_keep_last.py input.po output.po", file=sys.stderr)
    sys.exit(1)


input_file = sys.argv[1]
output_file = sys.argv[2]


with open(input_file, "r", encoding="utf-8") as f:
    content = f.read()


def split_entries(text):
    entries = []
    current = []

    for line in text.splitlines(keepends=True):
        if line.strip() == "":
            if current:
                entries.append("".join(current))
                current = []
        else:
            current.append(line)

    if current:
        entries.append("".join(current))

    return entries


def read_po_string(lines, start_index):
    value = ""
    i = start_index

    first = lines[i].strip()

    m = re.match(
        r'^(msgctxt|msgid|msgid_plural|msgstr(?:\[[0-9]+\])?)\s+(.*)$',
        first
    )

    if not m:
        return "", i

    raw = m.group(2).strip()

    try:
        value += ast.literal_eval(raw)
    except Exception:
        pass

    i += 1

    while i < len(lines):
        s = lines[i].strip()

        if not s.startswith('"'):
            break

        try:
            value += ast.literal_eval(s)
        except Exception:
            pass

        i += 1

    return value, i - 1


def entry_key(entry):
    lines = entry.splitlines()
    msgctxt = None
    msgid = None

    i = 0

    while i < len(lines):
        stripped = lines[i].strip()

        if stripped.startswith("msgctxt "):
            msgctxt, i = read_po_string(lines, i)

        elif stripped.startswith("msgid "):
            msgid, i = read_po_string(lines, i)
            break

        i += 1

    if msgid is None:
        return None

    return (msgctxt, msgid)


def po_quote(s):
    return '"' + s.replace("\\", "\\\\").replace('"', '\\"').replace("\n", "\\n") + '"'


def clean_conflict_msgstr(entry):
    """
    Ripulisce i msgstr sporchi generati da merge gettext tipo:

    #-#-#-#-# file1.po #-#-#-#-#
    Traduzione vecchia
    #-#-#-#-# file2.po #-#-#-#-#
    Traduzione nuova

    Tiene solo l'ultima traduzione utile.
    """

    if "#-#-#-#-#" not in entry:
        return entry

    lines = entry.splitlines()
    new_lines = []
    i = 0

    while i < len(lines):
        stripped = lines[i].strip()

        if stripped.startswith("msgstr "):
            msgstr_value, end_i = read_po_string(lines, i)

            if "#-#-#-#-#" in msgstr_value:
                parts = re.split(
                    r'#-#-#-#-#.*?#-#-#-#-#\n?',
                    msgstr_value,
                    flags=re.DOTALL
                )

                parts = [p.strip() for p in parts if p.strip()]
                chosen = parts[-1] if parts else ""

                new_lines.append('msgstr ""')

                if chosen:
                    new_lines.append(po_quote(chosen))
            else:
                new_lines.extend(lines[i:end_i + 1])

            i = end_i + 1
            continue

        if re.match(r"msgstr\[[0-9]+\]\s+", stripped):
            msgstr_value, end_i = read_po_string(lines, i)

            if "#-#-#-#-#" in msgstr_value:
                parts = re.split(
                    r'#-#-#-#-#.*?#-#-#-#-#\n?',
                    msgstr_value,
                    flags=re.DOTALL
                )

                parts = [p.strip() for p in parts if p.strip()]
                chosen = parts[-1] if parts else ""

                prefix = stripped.split(None, 1)[0]
                new_lines.append(f'{prefix} ""')

                if chosen:
                    new_lines.append(po_quote(chosen))
            else:
                new_lines.extend(lines[i:end_i + 1])

            i = end_i + 1
            continue

        new_lines.append(lines[i])
        i += 1

    return "\n".join(new_lines) + "\n"


entries = split_entries(content)

header_entries = []
normal_entries = []

for entry in entries:
    if not entry.strip():
        continue

    key = entry_key(entry)

    # Header gettext: msgid ""
    if key == (None, ""):
        header_entries.append(clean_conflict_msgstr(entry))
        continue

    if key is None:
        header_entries.append(entry)
        continue

    normal_entries.append((key, clean_conflict_msgstr(entry)))


# Tiene SOLO l'ultima occorrenza per ogni coppia msgctxt/msgid.
last_by_key = {}
order = []

for key, entry in normal_entries:
    if key not in last_by_key:
        order.append(key)

    last_by_key[key] = entry


with open(output_file, "w", encoding="utf-8") as f:
    for entry in header_entries:
        f.write(entry.rstrip())
        f.write("\n\n")

    for key in order:
        f.write(last_by_key[key].rstrip())
        f.write("\n\n")