// Copyright (c) 2017-2020, scoobybejesus
// Redistributions must include the license: https://github.com/scoobybejesus/cryptools/blob/master/LEGAL.txt

use std::error::Error;
use std::process;
use std::fs::File;
use std::cell::{RefCell};
use std::collections::{HashMap};
use std::path::PathBuf;

use chrono::NaiveDate;
use decimal::d128;

use crate::transaction::{Transaction, ActionRecord};
use crate::account::{Account, RawAccount};
use crate::decimal_utils::{round_d128_1e8};


pub fn import_from_csv(
    import_file_path: PathBuf,
    iso_date_style: bool,
    separator: &String,
    raw_acct_map: &mut HashMap<u16, RawAccount>,
    acct_map: &mut HashMap<u16, Account>,
    action_records: &mut HashMap<u32, ActionRecord>,
    transactions_map: &mut HashMap<u32, Transaction>,
) -> Result<(), Box<dyn Error>> {

    let file = match File::open(import_file_path) {
        Ok(x) => {
            // println!("\nCSV ledger file opened successfully.\n");
            x
        },
        Err(e) => {
            println!("Invalid import_file_path");
            eprintln!("System error: {}", e);
            std::process::exit(1);
        }
    };

    let mut rdr = csv::ReaderBuilder::new()
        .has_headers(true)
        .from_reader(file);

    import_accounts(&mut rdr, raw_acct_map, acct_map)?;

    import_transactions(
        &mut rdr,
        iso_date_style,
        &separator,
        action_records,
        transactions_map,
    )?;

    Ok(())
}

fn import_accounts(
    rdr: &mut csv::Reader<File>,
    raw_acct_map: &mut HashMap<u16, RawAccount>,
    acct_map: &mut HashMap<u16, Account>,
) -> Result<(), Box<dyn Error>> {

    let header1 = rdr.headers()?.clone();   //  account_num
    let mut header2: csv::StringRecord = csv::StringRecord::new();  //  name
    let mut header3: csv::StringRecord = csv::StringRecord::new();  //  ticker
    let header4: csv::StringRecord; //  is_margin

    // Account Creation loop.  With rdr.has_headers() set to true above, the first record here is the second row of the CSV
    for result in rdr.records() {
        //  This initial iteration through records will break after the 4th row, after accounts have been created
        let record = result?;
        if header2.len() == 0 {
            header2 = record.clone();
            continue    //  After header2 is set, continue to next record
        }
        else if header3.len() == 0 {
            header3 = record.clone();
            continue    //  After header3 is set, continue to next record
        }
        else {
            header4 = record.clone();
            // println!("Assigned last header, record: {:?}", record);

            // A StringRecord doesn't accept the same range indexing needed below, so a Vec of Strings will be used
            let headerstrings: Vec<String> = header1.into_iter().map(|field| field.to_string()).collect();

            let acct_num_warn = "Transactions will not import correctly if account numbers in the CSV import file aren't
ordered chronologically (i.e., beginning in column 4 - the 1st account column - the value should be 1.
The next column's value should be 2, then 3, etc, until the final account).";

            // Header row variables have been set.  It's now time to set up the accounts.
            println!("\nCreating accounts...");

            let length = &headerstrings.len();

            for (idx, field) in headerstrings[3..*length].iter().enumerate() {

                // Parse account numbers.
                let account_num = field.trim().parse::<u16>().expect(&format!("Header row account number should parse into u16: {}", field));
                // For now, their columns aren't remembered.  Instead, they must have a particular index. 0th idx is the 1st account, and so on.
                if account_num != ((idx + 1) as u16) {
                    println!("FATAL: CSV Import: {}", acct_num_warn);
                    std::process::exit(1);
                }

                let ind = idx+3; // Add three because the idx skips the first three 'key' columns
                let name:String = header2[ind].trim().to_string();
                let ticker:String = header3[ind].trim().to_string();   //  no .to_uppercase() b/c margin...
                let margin_string = &header4.clone()[ind];

                let is_margin:bool = match margin_string.to_lowercase().trim() {
                    "no" | "non" | "false" => false,
                    "yes" | "margin" | "true" => true,
                    _ => {
                        println!("\n FATAL: CSV Import: Couldn't parse margin value for account {} {} \n",account_num, name);
                        process::exit(1)
                    }
                };

                let just_account: RawAccount = RawAccount {
                    account_num,
                    name,
                    ticker,
                    is_margin,
                };

                raw_acct_map.insert(account_num, just_account);

                let account: Account = Account {
                    raw_key: account_num,
                    list_of_lots: RefCell::new([].to_vec())
                };

                acct_map.insert(account_num, account);
            }
            break    //  This `break` exits this scope so `accounts` can be accessed in `import_transactions`. The rdr stays put.
        }
    };
    Ok(())
}

fn import_transactions(
    rdr: &mut csv::Reader<File>,
    iso_date_style: bool,
    separator: &String,
    action_records: &mut HashMap<u32, ActionRecord>,
    txns_map: &mut HashMap<u32, Transaction>,
) -> Result<(), Box<dyn Error>> {

    let mut this_tx_number = 0;
    let mut this_ar_number = 0;
    let mut changed_action_records = 0;
    let mut changed_txn_num = Vec::new();

    println!("Creating transactions...");

    for result in rdr.records() {

        //  rdr's cursor is at row 5, which is the first transaction row
        let record = result?;
        this_tx_number += 1;

        //  First, initialize metadata fields.
        let mut this_tx_date: &str = "";
        let mut this_proceeds: &str;
        let mut this_memo: &str = "";
        let mut this: String;
        let mut proceeds_parsed = 0f32;

        //  Next, create action_records.
        let mut action_records_map_keys_vec: Vec<u32> = Vec::with_capacity(2);
        let mut outgoing_ar: Option<ActionRecord> = None;
        let mut incoming_ar: Option<ActionRecord> = None;
        let mut outgoing_ar_num: Option<u32> = None;
        let mut incoming_ar_num: Option<u32> = None;

        for (idx, field) in record.iter().enumerate() {

            //  Set metadata fields on first three fields.
            if idx == 0 { this_tx_date = field; }
            else if idx == 1 {
                this = field.replace(",", "");
                this_proceeds = this.as_str();
                proceeds_parsed = this_proceeds.parse::<f32>()?;
            }
            else if idx == 2 { this_memo = field; }

            //  Check for empty strings. If not empty, it's a value for an action_record.
            else if field != "" {
                this_ar_number += 1;
                let ind = idx;  //  starts at 3, which is the fourth field
                let acct_idx = ind - 2; //  acct_num and acct_key would be idx + 1, so subtract 2 from ind to get 1
                let account_key = acct_idx as u16;

                // TODO: implement conversion for negative numbers surrounded in parentheses
                let amount_str = field.replace(",", "");
                let amount = amount_str.parse::<d128>().unwrap();
                let amount_rounded = round_d128_1e8(&amount);
                if amount != amount_rounded { changed_action_records += 1; changed_txn_num.push(this_tx_number); }

                let action_record = ActionRecord {
                    account_key,
                    amount: amount_rounded,
                    tx_key: this_tx_number,
                    self_ar_key: this_ar_number,
                    movements: RefCell::new([].to_vec()),
                };

                if amount > d128!(0.0) {
                    incoming_ar = Some(action_record);
                    incoming_ar_num = Some(this_ar_number);
                    action_records_map_keys_vec.push(incoming_ar_num.unwrap())
                } else {
                    outgoing_ar = Some(action_record);
                    outgoing_ar_num = Some(this_ar_number);
                    action_records_map_keys_vec.insert(0, outgoing_ar_num.unwrap())
                };
            }
        }

        if let Some(incoming_ar) = incoming_ar {
            let x = incoming_ar_num.unwrap();
            action_records.insert(x, incoming_ar);
        }

        if let Some(outgoing_ar) = outgoing_ar {
            let y = outgoing_ar_num.unwrap();
            action_records.insert(y, outgoing_ar);
        }

        let format_yy: String;
        let format_yyyy: String;

        if iso_date_style {
            format_yyyy = "%Y".to_owned() + separator + "%m" + separator + "%d";
            format_yy = "%y".to_owned() + separator + "%m" + separator + "%d";
        } else {
            format_yyyy = "%m".to_owned() + separator + "%d" + separator + "%Y";
            format_yy = "%m".to_owned() + separator + "%d" + separator + "%y";
        }

        let tx_date = NaiveDate::parse_from_str(this_tx_date, &format_yy)
            .unwrap_or_else(|_| NaiveDate::parse_from_str(this_tx_date, &format_yyyy)
            .expect("
FATAL: Transaction date parsing failed. You must tell the program the format of the date in your CSV Input File. The date separator \
is expected to be a hyphen. The dating format is expected to be \"American\" (%m-%d-%y), not ISO 8601 (%y-%m-%d). You may set different \
date format options via command line flag, environment variable or .env file. Perhaps first run with `--help` or see `.env.example.`\n")
        );

        let transaction = Transaction {
            tx_number: this_tx_number,
            date_as_string: this_tx_date.to_string(),
            date: tx_date,
            user_memo: this_memo.to_string(),
            proceeds: proceeds_parsed,
            action_record_idx_vec: action_records_map_keys_vec,
        };

        txns_map.insert(this_tx_number, transaction);
    };

    if changed_action_records > 0 {
        println!("  Changed actionrecord amounts due to rounding precision: {}. Changed txn numbers: {:?}.", changed_action_records, changed_txn_num);
    }

    Ok(())
}