import re

import pandas as pd
from opencc import OpenCC

from era_data import dynasty_alias, KNOWN_ERAS

cc = OpenCC('t2s')


# === 中文数字转阿拉伯数字 ===
def chinese_to_num(text):
    text = text.replace("卅", "三十").replace("卌", "四十")
    if text in ["元", "元年"]:
        return 1

    chinese_numerals = {
        '零': 0, '〇': 0, '○': 0,
        '一': 1, '二': 2, '三': 3, '四': 4, '五': 5, '六': 6, '七': 7, '八': 8, '九': 9,
        '十': 10, '百': 100, '千': 1000,
        '壹': 1, '貳': 2, '叁': 3, '肆': 4, '伍': 5, '陸': 6, '柒': 7, '捌': 8, '玖': 9, '拾': 10,
        '卄': 20, '廿': 20, '卅': 30, '卌': 40,
    }

    if text in chinese_numerals:
        return chinese_numerals[text]

    if '十' in text:
        parts = text.split('十')
        total = 0
        if parts[0] == '':
            total += 10
        else:
            total += chinese_numerals.get(parts[0], 0) * 10
        if len(parts) > 1 and parts[1]:
            total += chinese_numerals.get(parts[1], 0)
        return total

    if '廿' in text or '卄' in text:
        return 20 + (chinese_numerals.get(text[-1], 0) if len(text) > 1 else 0)
    if '卅' in text:
        return 30 + (chinese_numerals.get(text[-1], 0) if len(text) > 1 else 0)

    # 混合数字（如"二零〇一"）
    total = 0
    for ch in text:
        total = total * 10 + chinese_numerals.get(ch, int(ch) if ch.isdigit() else 0)
    return total


# 朝代别名见 era_data.py


def normalize_dynasty_name(dynasty):
    if not dynasty:
        return dynasty
    # 先将繁体转简体
    simplified = cc.convert(dynasty)
    # 查别名表（简体）
    for prefix, true_name in dynasty_alias.items():
        if simplified.startswith(prefix):
            return true_name
    # 直接匹配朝代字典（简体）
    for known_dynasty in era_dict.keys():
        if simplified.startswith(known_dynasty) or known_dynasty.startswith(simplified):
            return known_dynasty
    return simplified


# === 年号表 ===
era_df = pd.read_csv("中国年号.csv")
era_df["年号"] = era_df["年号"].map(lambda x: cc.convert(str(x)))
era_df["所属朝代"] = era_df["所属朝代"].map(lambda x: cc.convert(str(x)))

era_dict = {}
for _, row in era_df.iterrows():
    dynasty, era, start = row["所属朝代"], row["年号"], int(row["公元纪年"])
    era_dict.setdefault(dynasty, {})[era] = start


# === 干支纪年 ===
_tiangan = '甲乙丙丁戊己庚辛壬癸'
_dizhi = '子丑寅卯辰巳午未申酉戌亥'
_ganzhi_to_offset = {}
for i in range(60):
    tg = _tiangan[i % 10]
    dz = _dizhi[i % 12]
    _ganzhi_to_offset[tg + dz] = i  # 0-based: 甲子=0

def ganzhi_to_era_year(ganzhi: str) -> int:
    """干支转年数（1-based）：甲子=1, 乙丑=2, ..., 癸亥=60"""
    return _ganzhi_to_offset.get(ganzhi, -1) + 1


def gregorian_to_ganzhi(year: int) -> str:
    """按项目约定将公元年转换为干支（公元4年为甲子）。"""
    offset = (year - 4) % 60
    return _tiangan[offset % 10] + _dizhi[offset % 12]


_gz_pair = '[' + _tiangan + '][' + _dizhi + ']'

# === 数字转中文 ===
def arabic_to_chinese_year(num: int) -> str:
    digits = "〇一二三四五六七八九"
    if num < 0:
        return '-' + ''.join(digits[int(d)] for d in str(abs(num)))
    return ''.join(digits[int(d)] for d in str(num))


# === 古代年号正则 ===
# 从 era_dict 构建朝代匹配组（按长度降序排列，优先匹配长朝代名如"北宋"而非"北"）
# 额外添加常见但不在CSV中的朝代简称（如"汉"）
_extra_dynasty_names = ['汉', '晋', '宋', '周']
_dynasty_names = sorted(
    list(era_dict.keys()) + [d for d in _extra_dynasty_names if d not in era_dict],
    key=len, reverse=True
)
_dynasty_alt = '|'.join(re.escape(d) for d in _dynasty_names)
# 常见朝代前缀（大、皇等），用于匹配"大唐""大清"等
_dynasty_prefix = '大皇前后胡'
# 非元年数字字符（排除元，避免歧义：建元元年中第一个元是年号的一部分）
_year_digits = '〇零一二三四五六七八九十廿卄卅卌'

# 已知年号白名单见 era_data.py

# 预编译已知年号正则片段（按长度降序，优先匹配长年号如"太平兴国"而非"太平"）
_known_era_alt = '|'.join(sorted(KNOWN_ERAS, key=len, reverse=True))
_known_era_group = r'(?P<era>' + _known_era_alt + r')'
_yd = '[' + _year_digits + ']'

def _build_pattern(with_dynasty=True):
    """构建年号正则：已知年号优先 + 通用兜底（仅限有朝代前缀时）"""
    if with_dynasty:
        # 朝代前缀模式：加(?<![一-鿿])防止"元"在"开元"中被当朝代
        dynasty_part = r'(?P<dynasty>(?:(?<![一-鿿])[' + _dynasty_prefix + r'](?:' + _dynasty_alt + r'))|(?:(?<![一-鿿])' + _dynasty_alt + r'))'
        boundary = ''
    else:
        dynasty_part = r'(?P<dynasty>)'
        # 无朝代模式不加边界（允许年号跟在其他汉字后面，如"永乐大帝在永乐三年"）
        boundary = ''

    if with_dynasty:
        # 有朝代前缀：年号后直接跟年份数字，无需额外约束
        era_year = _known_era_group + r'(?P<year>' + _yd + r'+)年'
        era_yuan = _known_era_group + r'元年'
        patterns = [
            re.compile(dynasty_part + boundary + era_year),
            re.compile(dynasty_part + boundary + era_yuan),
            # 通用兜底（2-8字）
            re.compile(dynasty_part + boundary + r'(?P<era>[一-鿿]{2,8})' + r'(?P<year>' + _yd + r'+)年'),
            re.compile(dynasty_part + boundary + r'(?P<era>[一-鿿]{2,8})元年'),
        ]
    else:
        # 无朝代前缀：年号后必须紧跟年份数字（前瞻断言），防止"永乐大帝"误匹配
        _year_ahead = r'(?=' + _yd + r'+年|元年)'
        era_year = _known_era_group + _year_ahead + r'(?P<year>' + _yd + r'+)年'
        era_yuan = _known_era_group + _year_ahead + r'元年'
        patterns = [
            re.compile(dynasty_part + boundary + era_year),
            re.compile(dynasty_part + boundary + era_yuan),
        ]
    return patterns

# 无朝代模式只匹配已知年号（避免误匹配如"国"被当年号）
_patterns_no_dynasty = _build_pattern(with_dynasty=False)
# 有朝代模式：已知年号 + 通用兜底
_patterns_dynasty = _build_pattern(with_dynasty=True)


# === 主函数 ===
def extract_era_years(text):
    # 去除标记用的方括号（用户标注用，非原文内容）
    text = text.replace('[', '').replace(']', '')
    original_text = text
    simplified_text = cc.convert(text)
    results = []

    # === 1. 民国 ===
    minguo_pattern = re.compile(r'民[国國]\s*([〇零一二三四五六七八九十百廿卄卅卌元\d]+)\s*年')
    for m in minguo_pattern.finditer(simplified_text):
        year_text = m.group(1)
        year_num = chinese_to_num(year_text)
        start, end = m.start(), m.end()
        raw_fan = original_text[start:end]
        results.append({
            "原文": raw_fan,
            "原文(简体)": m.group(0),
            "朝代": "民国",
            "年号": "民国纪年",
            "年数": year_num,
            "公元": 1911 + year_num,
            "公元中文": f"{arabic_to_chinese_year(1911 + year_num)}年",
            "位置": {"起始": start, "结束": end},
            "类型": "民国纪年",
        })

    # 1b. 民国+干支纪年（如"民国丁卯""民国甲戌"）
    minguo_gz = re.compile(r'民[国國]\s*(?P<ganzhi>' + _gz_pair + r')')
    for m in minguo_gz.finditer(simplified_text):
        ganzhi = m.group("ganzhi")
        gz_offset = _ganzhi_to_offset.get(ganzhi, -1)
        if gz_offset < 0:
            continue
        # 民国元年=1912, base_gz = (1912-4)%60 = 8 (己酉)
        base_gz = (1912 - 4) % 60
        year_in_era = ((gz_offset - base_gz) % 60) + 1
        gregorian = 1912 + year_in_era - 1
        start, end = m.start(), m.end()
        raw_fan = original_text[start:end]
        results.append({
            "原文": raw_fan,
            "原文(简体)": m.group(0),
            "朝代": "民国",
            "年号": "民国纪年",
            "年数": year_in_era,
            "干支": ganzhi,
            "公元": gregorian,
            "公元中文": f"{arabic_to_chinese_year(gregorian)}年",
            "位置": {"起始": start, "结束": end},
            "类型": "民国纪年（干支）",
        })

    # === 2. 公元（允许无"年"字）===
    gongyuan_pattern = re.compile(
        r'(公元)?\s*([〇零○O一二三四五六七八九\d]{3,4})\s*(?:（.*?）)?\s*(年)?'
    )
    for m in gongyuan_pattern.finditer(simplified_text):
        year_text = m.group(2)
        year_num = chinese_to_num(year_text)
        if not (1000 <= year_num <= 2100):
            continue
        start, end = m.start(), m.end()
        raw_fan = original_text[start:end]
        era_type = "公元纪年（中华人民共和国）" if year_num >= 1949 else "公元纪年（近代/其他）"
        results.append({
            "原文": raw_fan,
            "原文(简体)": m.group(0),
            "类型": era_type,
            "公元": year_num,
            "公元中文": f"{arabic_to_chinese_year(year_num)}年",
            "位置": {"起始": start, "结束": end},
        })

    # === 3. 干支纪年（如"清雍正乙巳十一月十二午时生"）===
    covered = set()
    def _process_ganzhi_match(m):
        """处理干支纪年匹配"""
        raw_dynasty = m.group("dynasty") if "dynasty" in m.groupdict() else ""
        dynasty = normalize_dynasty_name(raw_dynasty or "")
        era = cc.convert(m.group("era"))
        ganzhi = m.group("ganzhi")
        if ganzhi not in _ganzhi_to_offset:
            return

        # 查找朝代和基准年
        base = None
        if dynasty:
            for d, eras in era_dict.items():
                if dynasty in d or d in dynasty:
                    if era in eras:
                        base = eras[era]
                        dynasty = d
                        break
        if not base:
            for d, eras in era_dict.items():
                if era in eras:
                    base = eras[era]
                    dynasty = d
                    break
        if not base:
            return

        # 干支60年循环：计算基准年的干支位置，再求偏移
        base_gz = (base - 4) % 60  # 公元4年=甲子(0)，所以偏移=4
        gz_offset = _ganzhi_to_offset.get(ganzhi, 0)  # 0-based
        year_in_era = ((gz_offset - base_gz) % 60) + 1  # 1-based年数
        gregorian = base + year_in_era - 1
        start, end = m.start(), m.end()
        if any(pos in covered for pos in range(start, end)):
            return
        covered.update(range(start, end))
        raw_fan = original_text[start:end]
        results.append({
            "原文": raw_fan,
            "原文(简体)": m.group(0),
            "朝代": dynasty,
            "年号": era,
            "年数": year_in_era,
            "干支": ganzhi,
            "公元": gregorian,
            "公元中文": f"{arabic_to_chinese_year(gregorian)}年",
            "位置": {"起始": start, "结束": end},
            "类型": "干支纪年",
        })

    # 模式A：有朝代前缀（如"清雍正乙巳"）
    # 单字年号加前瞻(?![地支])，防止单字年号"丙"吞掉天干"丙午"中的"丙"
    _gz_era_group = r'(?P<era>' + '|'.join(
        (re.escape(e) + (r'(?![子丑寅卯辰巳午未申酉戌亥])' if len(e) == 1 else ''))
        for e in sorted(KNOWN_ERAS, key=len, reverse=True)
    ) + r')'
    ganzhi_dynasty = re.compile(
        r'(?P<dynasty>(?:(?<![一-鿿])[' + _dynasty_prefix + r'](?:' + _dynasty_alt + r'))|(?:(?<![一-鿿])' + _dynasty_alt + r'))'
        + _gz_era_group
        + r'(?P<ganzhi>' + _gz_pair + r')(?:年)?'
    )
    for m in ganzhi_dynasty.finditer(simplified_text):
        _process_ganzhi_match(m)

    # 模式B：无朝代前缀（如"嘉庆癸亥"），年号≥2字符避免天干误匹配
    _long_era_names = [e for e in KNOWN_ERAS if len(e) >= 2]
    _long_era_alt = '|'.join(sorted(_long_era_names, key=len, reverse=True))
    ganzhi_no_dynasty = re.compile(
        r'(?P<dynasty>)'
        + r'(?P<era>' + _long_era_alt + r')'
        + r'(?P<ganzhi>' + _gz_pair + r')(?:年)?'
    )
    for m in ganzhi_no_dynasty.finditer(simplified_text):
        _process_ganzhi_match(m)

    # === 4. 古代年号 ===

    def _process_era_match(m, year_override=None):
        """处理一个年号正则匹配结果"""
        raw_dynasty = m.group("dynasty") if "dynasty" in m.groupdict() else ""
        dynasty = normalize_dynasty_name(raw_dynasty or "")
        era = cc.convert(m.group("era"))

        # 过滤误匹配：年号是单个数字字符（如"民国二十六年"中的"二"）
        if len(era) == 1 and era in '零一二三四五六七八九十廿卄卅卌':
            return
        # 过滤误匹配：年号全是数字汉字（如"元一九五二年"中的"一九五"）
        if era and all(ch in '零一二三四五六七八九十〇' for ch in era):
            return
        year_text = year_override if year_override is not None else m.group("year")
        year_num = chinese_to_num(year_text)
        base = None

        if dynasty:
            for d, eras in era_dict.items():
                if dynasty in d or d in dynasty:
                    if era in eras:
                        base = eras[era]
                        dynasty = d
                        break
        else:
            candidates = []
            for d, eras in era_dict.items():
                if era in eras:
                    candidates.append((d, eras[era]))
            if len(candidates) == 1:
                dynasty, base = candidates[0]
            elif len(candidates) > 1:
                dynasty, base = candidates[0]

        start, end = m.start(), m.end()
        raw_fan = original_text[start:end]
        covered.update(range(start, end))
        if base:
            gregorian = base + year_num - 1
            results.append({
                "原文": raw_fan,
                "原文(简体)": m.group(0),
                "朝代": dynasty,
                "年号": era,
                "年数": year_num,
                "公元": gregorian,
                "公元中文": f"{arabic_to_chinese_year(gregorian)}年",
                "位置": {"起始": start, "结束": end},
                "类型": "古代纪年",
            })
        else:
            results.append({
                "原文": raw_fan,
                "原文(简体)": m.group(0),
                "朝代": dynasty,
                "年号": era,
                "年数": year_num,
                "位置": {"起始": start, "结束": end},
                "类型": "古代纪年（未匹配）",
            })

    # 收集所有匹配，对于重叠区间保留覆盖范围更大的（如"金大定元年"优先于"大定元年"）
    all_matches = []
    for pat in _patterns_no_dynasty:
        for m in pat.finditer(simplified_text):
            has_year = "year" in m.groupdict() and m.group("year") is not None
            all_matches.append((m, None if has_year else "元", False))
    for pat in _patterns_dynasty:
        for m in pat.finditer(simplified_text):
            has_year = "year" in m.groupdict() and m.group("year") is not None
            all_matches.append((m, None if has_year else "元", True))

    # 按覆盖范围降序排列（长的优先），同长度时朝代模式优先
    all_matches.sort(key=lambda x: (x[0].end() - x[0].start(), x[2]), reverse=True)

    for m, year_override, _is_dynasty in all_matches:
        if not any(pos in covered for pos in range(m.start(), m.end())):
            _process_era_match(m, year_override=year_override)

    for result in results:
        if result.get("公元") is not None:
            result.setdefault("干支", gregorian_to_ganzhi(result["公元"]))

    return results


def convert_text(text):
    results = extract_era_years(text)
    return results