biovault 0.1.53

use anyhow::Result;
use serde::{Deserialize, Serialize};
use std::collections::HashSet;
use std::fs::File;
use std::io::{BufRead, BufReader};
use std::path::Path;

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct GenotypeMetadata {
    pub data_type: String,
    pub source: Option<String>,
    pub grch_version: Option<String>,
    pub row_count: Option<i64>,
    pub chromosome_count: Option<i64>,
    pub inferred_sex: Option<String>,
}

impl Default for GenotypeMetadata {
    fn default() -> Self {
        Self {
            data_type: "Unknown".to_string(),
            source: None,
            grch_version: None,
            row_count: None,
            chromosome_count: None,
            inferred_sex: None,
        }
    }
}

/// Detect if a file is a genotype file and extract metadata (fast version - header only)
pub fn detect_genotype_metadata(file_path: &str) -> Result<GenotypeMetadata> {
    let path = Path::new(file_path);

    if !path.exists() {
        return Ok(GenotypeMetadata::default());
    }

    let file = File::open(path)?;
    let reader = BufReader::new(file);
    let mut lines = reader.lines();

    // Read first 50 lines for header analysis
    let mut header_text = String::new();
    let mut data_lines = Vec::new();
    let mut line_count = 0;
    let max_header_lines = 50;

    for line_result in &mut lines {
        let line = line_result?;
        line_count += 1;

        // Collect lines starting with # or comment markers as header
        if line.starts_with('#') || line.starts_with("//") {
            header_text.push_str(&line);
            header_text.push('\n');
        } else if !line.trim().is_empty() {
            // Non-comment, non-empty line - potential data
            data_lines.push(line);

            // Collect up to 10 data lines for structure validation
            if data_lines.len() >= 10 {
                break;
            }
        }

        if line_count >= max_header_lines {
            break;
        }
    }

    // Check if this looks like a genotype file
    let is_genotype = validate_genotype_structure(&data_lines);

    if !is_genotype {
        return Ok(GenotypeMetadata::default());
    }

    // File is a genotype - extract metadata from headers
    let header_lower = header_text.to_lowercase();

    let source = detect_source(&header_lower);
    let grch_version = detect_grch_version(&header_lower);

    Ok(GenotypeMetadata {
        data_type: "Genotype".to_string(),
        source,
        grch_version,
        row_count: None,
        chromosome_count: None,
        inferred_sex: None,
    })
}

/// Analyze genotype file for row count, chromosome count, and inferred sex (slow - reads entire file)
pub fn analyze_genotype_file(file_path: &str) -> Result<GenotypeMetadata> {
    let path = Path::new(file_path);

    if !path.exists() {
        return Ok(GenotypeMetadata::default());
    }

    // Count total rows and chromosomes by reading the entire file
    let (row_count, chromosome_count, inferred_sex) = count_rows_and_chromosomes(file_path)?;

    Ok(GenotypeMetadata {
        data_type: "Unknown".to_string(),
        source: None,
        grch_version: None,
        row_count: Some(row_count as i64),
        chromosome_count: Some(chromosome_count as i64),
        inferred_sex: Some(inferred_sex),
    })
}

/// Count data rows and unique chromosomes in a genotype file
fn count_rows_and_chromosomes(file_path: &str) -> Result<(usize, usize, String)> {
    let file = File::open(file_path)?;
    let reader = BufReader::new(file);

    let mut row_count = 0;
    let mut chromosomes = HashSet::new();

    for line_result in reader.lines() {
        let line = line_result?;

        // Skip comments and empty lines
        if line.starts_with('#') || line.starts_with("//") || line.trim().is_empty() {
            continue;
        }

        // Count this as a data row
        row_count += 1;

        // Extract chromosome (column 2 in TSV format)
        let parts: Vec<&str> = line.split('\t').collect();
        if parts.len() >= 2 {
            let chr = parts[1].trim();
            chromosomes.insert(chr.to_string());
        }
    }

    // Infer sex from chromosome presence
    let has_x = chromosomes.contains("X") || chromosomes.contains("23");
    let has_y = chromosomes.contains("Y") || chromosomes.contains("24");

    let inferred_sex = if has_y {
        "Male".to_string()
    } else if has_x && !has_y {
        "Female".to_string()
    } else {
        "Unknown".to_string()
    };

    Ok((row_count, chromosomes.len(), inferred_sex))
}

/// Validate that data lines match genotype file structure
fn validate_genotype_structure(data_lines: &[String]) -> bool {
    if data_lines.is_empty() {
        return false;
    }

    let mut valid_lines = 0;

    for line in data_lines {
        let parts: Vec<&str> = line.split('\t').collect();

        // Should have 4 or 5 columns (rsid, chromosome, position, genotype, [optional])
        if parts.len() < 4 || parts.len() > 6 {
            continue;
        }

        // Check column 1: rsid (should start with 'rs' or 'i')
        let rsid = parts[0].trim();
        if !rsid.starts_with("rs") && !rsid.starts_with('i') {
            continue;
        }

        // Check column 2: chromosome (should be 1-22, X, Y, MT, or similar)
        let chr = parts[1].trim();
        if !is_valid_chromosome(chr) {
            continue;
        }

        // Check column 3: position (should be an integer)
        if parts[2].trim().parse::<u64>().is_err() {
            continue;
        }

        // Check column 4: genotype (should be valid genotype format)
        let genotype = parts[3].trim();
        if !is_valid_genotype(genotype) {
            continue;
        }

        valid_lines += 1;
    }

    // Consider it a genotype file if at least 70% of data lines are valid
    let threshold = (data_lines.len() * 7) / 10;
    valid_lines >= threshold
}

fn is_valid_chromosome(chr: &str) -> bool {
    // Check for numeric chromosomes 1-22
    if let Ok(num) = chr.parse::<u8>() {
        return (1..=22).contains(&num);
    }

    // Check for sex chromosomes and mitochondrial
    matches!(
        chr.to_uppercase().as_str(),
        "X" | "Y" | "MT" | "M" | "23" | "24"
    )
}

fn is_valid_genotype(genotype: &str) -> bool {
    // Valid genotypes include:
    // - Two-letter genotypes: AA, AG, TT, etc.
    // - Indels: D, I, DD, DI, II
    // - Missing: --, 00
    // - Single letters for haploid: A, T, G, C

    if genotype.is_empty() {
        return false;
    }

    let g = genotype.to_uppercase();

    // Missing data
    if g == "--" || g == "00" {
        return true;
    }

    // Check if all characters are valid nucleotides or indel markers
    for c in g.chars() {
        if !matches!(c, 'A' | 'T' | 'G' | 'C' | 'D' | 'I' | '-' | '0') {
            return false;
        }
    }

    // Valid length (1-2 characters)
    matches!(g.len(), 1 | 2)
}

/// Detect source from header text (case-insensitive)
fn detect_source(header_lower: &str) -> Option<String> {
    if header_lower.contains("23andme") {
        Some("23andMe".to_string())
    } else if header_lower.contains("ancestrydna") || header_lower.contains("ancestry dna") {
        Some("AncestryDNA".to_string())
    } else if header_lower.contains("genes for good") || header_lower.contains("genesforgood") {
        Some("Genes for Good".to_string())
    } else {
        Some("Unknown".to_string())
    }
}

/// Detect GRCh version from header text (case-insensitive)
fn detect_grch_version(header_lower: &str) -> Option<String> {
    // Build 36 / GRCh36 / hg18
    if header_lower.contains("build 36")
        || header_lower.contains("grch36")
        || header_lower.contains("hg18")
    {
        return Some("36".to_string());
    }

    // Build 37 / GRCh37 / hg19
    if header_lower.contains("build 37")
        || header_lower.contains("grch37")
        || header_lower.contains("hg19")
    {
        return Some("37".to_string());
    }

    // Build 38 / GRCh38 / hg38
    if header_lower.contains("build 38")
        || header_lower.contains("grch38")
        || header_lower.contains("hg38")
    {
        return Some("38".to_string());
    }

    Some("Unknown".to_string())
}

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

    #[test]
    fn test_valid_chromosome() {
        assert!(is_valid_chromosome("1"));
        assert!(is_valid_chromosome("22"));
        assert!(is_valid_chromosome("X"));
        assert!(is_valid_chromosome("Y"));
        assert!(is_valid_chromosome("MT"));
        assert!(!is_valid_chromosome("0"));
        assert!(!is_valid_chromosome("23"));
        assert!(!is_valid_chromosome("ABC"));
    }

    #[test]
    fn test_valid_genotype() {
        assert!(is_valid_genotype("AA"));
        assert!(is_valid_genotype("AG"));
        assert!(is_valid_genotype("TT"));
        assert!(is_valid_genotype("--"));
        assert!(is_valid_genotype("00"));
        assert!(is_valid_genotype("D"));
        assert!(is_valid_genotype("I"));
        assert!(is_valid_genotype("DD"));
        assert!(is_valid_genotype("A"));
        assert!(!is_valid_genotype(""));
        assert!(!is_valid_genotype("AAA"));
        assert!(!is_valid_genotype("XY"));
    }

    #[test]
    fn test_detect_source() {
        assert_eq!(
            detect_source("this is from 23andme"),
            Some("23andMe".to_string())
        );
        assert_eq!(
            detect_source("ancestrydna test"),
            Some("AncestryDNA".to_string())
        );
        assert_eq!(
            detect_source("genes for good data"),
            Some("Genes for Good".to_string())
        );
        assert_eq!(detect_source("unknown source"), Some("Unknown".to_string()));
    }

    #[test]
    fn test_detect_grch_version() {
        assert_eq!(detect_grch_version("build 36"), Some("36".to_string()));
        assert_eq!(detect_grch_version("grch37"), Some("37".to_string()));
        assert_eq!(detect_grch_version("hg38"), Some("38".to_string()));
        assert_eq!(
            detect_grch_version("no version info"),
            Some("Unknown".to_string())
        );
    }
}