// src/query_parser.rs
use regex::Regex;

/// 清洗用户输入的检索词，转换全角字符和中文标点
pub fn clean_query(query: &str) -> String {
    let mut cleaned = query.to_string();
    
    // 全角双引号 -> 半角双引号
    cleaned = cleaned.replace("“", "\"").replace("”", "\"");
    // 全角单引号 -> 半角单引号
    cleaned = cleaned.replace("‘", "'").replace("’", "'");
    // 全角括号 -> 半角括号
    cleaned = cleaned.replace("（", "(").replace("）", ")");
    // 全角逗号/分号
    cleaned = cleaned.replace("，", ",").replace("；", ";");
    
    cleaned.trim().to_string()
}

/// 提取 year 限定条件并返回 (start_year, end_year, query_without_year)
/// 例如: `hot subdwarf year:2020-2023` -> (Some(2020), Some(2023), "hot subdwarf")
pub fn extract_year_filter(query: &str) -> (Option<i32>, Option<i32>, String) {
    let cleaned = clean_query(query);
    
    // 匹配 year:2020-2023 或 year:2020
    let year_re = Regex::new(r"(?i)\byear:\s*(\d{4})(?:\s*-\s*(\d{4}))?\b").unwrap();
    
    if let Some(caps) = year_re.captures(&cleaned) {
        let start_year = caps.get(1).and_then(|m| m.as_str().parse::<i32>().ok());
        let end_year = caps.get(2)
            .and_then(|m| m.as_str().parse::<i32>().ok())
            .or(start_year); // 如果是单一年份 year:2020，结束年份也是 2020
            
        // 将 year 过滤子句从原始检索式中移除，避免污染基础文本匹配
        let without_year = year_re.replace_all(&cleaned, "").to_string();
        
        // 清理可能由于移除子句导致的多余 AND/OR 逻辑符或空格
        let cleanup_re = Regex::new(r"\s+(AND|OR|NOT)\s*$|^\s*(AND|OR|NOT)\s+|\s+(AND|OR)\s+(AND|OR)\s+").unwrap();
        let final_query = cleanup_re.replace_all(&without_year, " ").trim().to_string();
        
        return (start_year, end_year, final_query);
    }
    
    (None, None, cleaned)
}

/// 翻译成 NASA ADS (Apache Solr) 的检索式
pub fn to_ads_query(query: &str) -> String {
    let (start, end, rest_query) = extract_year_filter(query);
    let mut parts = Vec::new();
    
    // 处理剩余检索词项的字段映射 (如 abs: -> abstract:)
    let ads_rest = rest_query
        .replace("abs:", "abstract:")
        .replace("ti:", "title:")
        .replace("au:", "author:");
        
    if !ads_rest.trim().is_empty() {
        parts.push(ads_rest);
    }
    
    // 如果有时间范围，添加 Solr 范围语法
    if let Some(s) = start {
        if let Some(e) = end {
            parts.push(format!("year:[{} TO {}]", s, e));
        }
    }
    
    if parts.is_empty() {
        return "*:*".to_string();
    }
    
    if parts.len() == 1 {
        parts[0].clone()
    } else {
        // 合并
        format!("({}) AND {}", parts[0], parts[1])
    }
}

/// 翻译成 arXiv API 要求的检索式（Lucene 格式，强制要求重复字段前缀）
pub fn to_arxiv_query(query: &str) -> (String, Option<(i32, i32)>) {
    let (start, end, rest_query) = extract_year_filter(query);
    let cleaned_rest = rest_query;
    
    // 年份范围元组
    let year_range = start.map(|s| (s, end.unwrap_or(s)));
    
    if cleaned_rest.trim().is_empty() {
        return ("all:\"\"".to_string(), year_range);
    }
    
    // 自动为未限定前缀的检索短语/单词补全前缀
    // 逻辑：以空格、括号、运算符分割，为不带前缀的独立词/短语添加 "all:"。
    // 用正则简单分词翻译：
    // 我们找出所有的双引号短语，或者无空格单词，如果它们不是运算符（AND, OR, NOT, ANDNOT）且不带冒号前缀，则加上 all:
    let token_re = Regex::new(r#"(?s)(\b(?:title|author|abs|ti|au):)?("[^"]+"|\b[a-zA-Z0-9_\-\.\*]+)"#).unwrap();
    
    let mut translated = String::new();
    let mut last_pos = 0;
    
    for cap in token_re.captures_iter(&cleaned_rest) {
        let entire_match = cap.get(0).unwrap();
        let prefix = cap.get(1).map(|m| m.as_str()).unwrap_or("");
        let val = cap.get(2).map(|m| m.as_str()).unwrap_or("");
        
        // 拼装匹配项之间的非单词字符（如空格、括号、逻辑运算符）
        let between = &cleaned_rest[last_pos..entire_match.start()];
        translated.push_str(between);
        last_pos = entire_match.end();
        
        let val_upper = val.to_uppercase();
        if val_upper == "AND" || val_upper == "OR" || val_upper == "NOT" {
            // NOT 翻译为 ANDNOT，因为 arXiv 不支持单独的 NOT
            if val_upper == "NOT" {
                // 如果 NOT 前面已有空格，我们看是否需要补充 ANDNOT。
                // 替换为 ANDNOT
                translated.push_str("ANDNOT");
            } else {
                translated.push_str(val);
            }
        } else if prefix.is_empty() {
            // 没有前缀，补全默认的 all:
            translated.push_str(&format!("all:{}", val));
        } else {
            // 将 ti/title 等前缀标准化为 arXiv 标准前缀 (ti, au, abs)
            let standard_prefix = match prefix {
                "title:" | "ti:" => "ti:",
                "author:" | "au:" => "au:",
                "abs:" => "abs:",
                _ => prefix,
            };
            translated.push_str(&format!("{}{}", standard_prefix, val));
        }
    }
    
    if last_pos < cleaned_rest.len() {
        translated.push_str(&cleaned_rest[last_pos..]);
    }
    
    // 全局清理和修饰：如果翻译后的语句中依然有单独的 NOT，将其转换为 ANDNOT
    let translated_clean = translated
        .replace(" NOT ", " ANDNOT ")
        .replace("(NOT ", "(ANDNOT ");
        
    (translated_clean.trim().to_string(), year_range)
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_clean_query() {
        assert_eq!(clean_query("“hot subdwarf”"), "\"hot subdwarf\"");
        assert_eq!(clean_query("（hot OR subdwarf）"), "(hot OR subdwarf)");
    }

    #[test]
    fn test_extract_year_filter() {
        let (s, e, q) = extract_year_filter("hot subdwarf year:2020-2023");
        assert_eq!(s, Some(2020));
        assert_eq!(e, Some(2023));
        assert_eq!(q, "hot subdwarf");

        let (s, e, q) = extract_year_filter("year:2022 \"Gaia BH1\"");
        assert_eq!(s, Some(2022));
        assert_eq!(e, Some(2022));
        assert_eq!(q, "\"Gaia BH1\"");
    }

    #[test]
    fn test_to_ads_query() {
        let ads = to_ads_query("author:\"Althaus\" AND ti:\"hot subdwarf\" year:2020-2023");
        assert_eq!(ads, "(author:\"Althaus\" AND title:\"hot subdwarf\") AND year:[2020 TO 2023]");
    }

    #[test]
    fn test_to_arxiv_query() {
        let (arxiv, year) = to_arxiv_query("author:\"Althaus\" AND ti:\"hot subdwarf\" year:2020-2023");
        assert_eq!(arxiv, "au:\"Althaus\" AND ti:\"hot subdwarf\"");
        assert_eq!(year, Some((2020, 2023)));

        let (arxiv2, _) = to_arxiv_query("(\"hot subdwarf\" OR sdOB) AND Gaia NOT \"neutron star\"");
        assert_eq!(arxiv2, "(all:\"hot subdwarf\" OR all:sdOB) AND all:Gaia ANDNOT all:\"neutron star\"");
    }
}