use crate::model::Transaction;
use chrono::NaiveDate;
use std::fs::File;

pub fn parse(filename: &str) -> anyhow::Result<Vec<Transaction>> {
    let file = File::open(filename)?;
    let mut reader = csv::ReaderBuilder::new()
        .has_headers(true)
        .from_reader(file);

    let mut transactions = Vec::new();

    for result in reader.records() {
        let record = result?;
        if record.len() >= 4 {
            // Format: Date, Transaction Details, Funds Out, Funds In
            if let (Ok(date), Some(description)) = (
                NaiveDate::parse_from_str(record[0].trim(), "%m/%d/%Y"),
                record.get(1),
            ) {
                let account = "Simplii Financial".to_string();

                // Check Funds Out (expenses)
                if !record[2].trim().is_empty() {
                    if let Ok(amount) = record[2].parse::<f64>() {
                        transactions.push(Transaction::new(
                            date,
                            description.trim().to_string(),
                            -amount,
                            account.clone(),
                        ));
                    }
                }

                // Check Funds In (income/deposits)
                if !record[3].trim().is_empty() {
                    if let Ok(amount) = record[3].parse::<f64>() {
                        transactions.push(Transaction::new(
                            date,
                            description.trim().to_string(),
                            amount,
                            account.clone(),
                        ));
                    }
                }
            }
        }
    }
    Ok(transactions)
}

#[cfg(test)]
mod tests {
    use super::*;
    use std::io::Write;
    use tempfile::NamedTempFile;

    #[test]
    fn test_simplii_parser() {
        let csv_content = "Date, Transaction Details, Funds Out, Funds In \n05/31/2024, TRANSFER IN,,1205.61\n05/31/2024, TRANSFER OUT,1200.00,\n06/04/2024,EFT DEBIT EMBARK STUDENT FOUNDATION CHEQUE,25.00,";

        let mut temp_file = NamedTempFile::new().unwrap();
        temp_file.write_all(csv_content.as_bytes()).unwrap();
        temp_file.flush().unwrap();

        let transactions = parse(temp_file.path().to_str().unwrap()).unwrap();

        assert_eq!(transactions.len(), 3);

        // Transfer In (income)
        let transfer_in = &transactions[0];
        assert_eq!(
            transfer_in.date.format("%Y-%m-%d").to_string(),
            "2024-05-31"
        );
        assert_eq!(transfer_in.description.trim(), "TRANSFER IN");
        assert_eq!(transfer_in.amount, 1205.61);
        assert_eq!(transfer_in.account, "Simplii Financial");
        assert_eq!(transfer_in.category, Some("Transfer".to_string()));

        // Transfer Out (expense)
        let transfer_out = &transactions[1];
        assert_eq!(
            transfer_out.date.format("%Y-%m-%d").to_string(),
            "2024-05-31"
        );
        assert_eq!(transfer_out.description.trim(), "TRANSFER OUT");
        assert_eq!(transfer_out.amount, -1200.00);
        assert_eq!(transfer_out.account, "Simplii Financial");
        assert_eq!(transfer_out.category, Some("Transfer".to_string()));

        // EFT Debit (expense)
        let eft_debit = &transactions[2];
        assert_eq!(eft_debit.date.format("%Y-%m-%d").to_string(), "2024-06-04");
        assert_eq!(
            eft_debit.description.trim(),
            "EFT DEBIT EMBARK STUDENT FOUNDATION CHEQUE"
        );
        assert_eq!(eft_debit.amount, -25.00);
        assert_eq!(eft_debit.account, "Simplii Financial");
        // This gets categorized as "Other" since it doesn't match specific patterns
        assert!(eft_debit.category.is_some());
    }

    #[test]
    fn test_simplii_parser_empty_amounts() {
        let csv_content =
            "Date, Transaction Details, Funds Out, Funds In \n05/31/2024, EMPTY TRANSACTION,,";

        let mut temp_file = NamedTempFile::new().unwrap();
        temp_file.write_all(csv_content.as_bytes()).unwrap();
        temp_file.flush().unwrap();

        let transactions = parse(temp_file.path().to_str().unwrap()).unwrap();
        assert_eq!(transactions.len(), 0);
    }
}