use std::collections::HashSet;

use itertools::Itertools;

// use crate::{check::CheckLevel, data, import::import_from, io, show};
use crate::prelude::*;

mod comb;
mod infer;
mod txnmatch;

#[derive(clap::Parser)]
pub struct Invocation {
    /// path to treasure file
    #[clap(long, short, env = "HOARD_ROOT")]
    pub file: std::path::PathBuf,

    /// verbosity of output messages
    #[clap(long, short, action = clap::ArgAction::Count)]
    pub verbose: u8,

    #[clap(subcommand)]
    pub cmd: Command,
}

fn load_data(
    fsdata: &mut io::FilesystemData,
    invocation: &Invocation,
    level: check::CheckLevel,
) -> anyhow::Result<data::Hoard> {
    let path = std::fs::canonicalize(&invocation.file)?;
    match data::Hoard::load(fsdata, &path, level) {
        Ok(data) => Ok(data),
        Err(DataError::IOError(ioerror)) => Err(ioerror.into()),
        Err(DataError::Report(report)) => {
            report.eprint(fsdata)?;
            Err(anyhow::anyhow!("Error reported"))
        }
    }
}

#[derive(clap::Subcommand)]
pub enum Command {
    Summarize,
    Ledger {
        account: String,
        #[clap(long, short)]
        raw: bool
    },
    Reformat {
        #[clap(long)]
        /// do not add ID annotations to transactions lacking them
        skip_ids: bool,
    },
    Import {
        account: String,
        from: std::path::PathBuf,
        target: Option<std::path::PathBuf>,
    },
    Infer,
    Match {
        account: Option<data::AccountName>,
    },
    Comb {
        account: Option<data::AccountName>,
    },
}

fn summarize(data: &data::Hoard) {
    let positive = console::Style::new().green();
    let negative = console::Style::new().red();
    let neutral = console::Style::new();

    let Some(maxlen) = data.account_names().map(|v| v.len()).max() else {
        return;
    };

    for shortname in data.account_names().sorted_by_key(|an| an.as_str()) {
        if shortname.as_ref() == "initial" {
            continue;
        }
        if let Some(mut balances) = data.balance(shortname) {
            // insert a default balance of 0 if no balance is present
            if let Some(unit) = data.account_spec(shortname).unwrap().unit {
                balances.entry(unit).or_default();
            }
            let balances = balances
                .into_iter()
                .filter(|(_, b)| !b.is_zero())
                .sorted()
                .map(|(u, b)| {
                    (
                        u,
                        if b.is_sign_positive() {
                            positive.apply_to(b).to_string()
                        } else if b.is_sign_negative() {
                            negative.apply_to(b).to_string()
                        } else {
                            neutral.apply_to("0").to_string()
                        },
                    )
                });

            println!(
                "{shortname:maxlen$} {}",
                balances.map(|(u, b)| format!("{b:8} {u:5}")).join(" ")
            );
        }
    }
}

impl Command {
    pub fn run(&self, inv: &Invocation) -> anyhow::Result<()> {
        let mut fsdata = io::FilesystemData::default();

        match self {
            Self::Summarize => {
                let data = load_data(&mut fsdata, inv, Default::default())?;
                summarize(&data);
            }
            Self::Ledger { account, raw } => {
                let data = load_data(&mut fsdata, inv, check::CheckLevel::WellFormed)?;

                let aname = data::AccountName::new(account.as_str());

                if let Some(ld) = data.ledger_data_for(aname) {
                    if *raw {
                        for txn in ld {
                            show::show_transaction(Some(&data), &txn.borrow());
                        }
                    } else {
                        let tt = show::TransactionTable::default();
                        tt.show_refs(Some(&data), aname, ld.iter());
                    }
                } else {
                    log::error!("account not found!");
                }
            }
            Self::Reformat { skip_ids } => {
                let mut data = load_data(&mut fsdata, inv, check::CheckLevel::WellFormed)?;

                if !skip_ids {
                    let mut used_ids = HashSet::new();
                    for le in data.all_raw_ledger_data() {
                        let Some(txn) = le.as_transaction() else {
                            continue;
                        };
                        let Some(id) = txn.get_annotation("id") else {
                            continue;
                        };
                        used_ids.insert(id.to_owned());
                    }

                    // assign IDs if to transactions lacking them
                    for le in data.all_raw_ledger_data_mut() {
                        let Some(txn) = le.as_transaction_mut() else {
                            continue;
                        };
                        if txn.get_annotation("id").is_none() {
                            // generated unique ID
                            let mut id = nanoid::nanoid!(10);
                            while used_ids.contains(&id) {
                                id = nanoid::nanoid!(10);
                            }
                            // assign ID
                            txn.annotations.insert("id".to_string(), id);
                        }
                    }
                }

                data::format_ledger(&mut fsdata, &data, data.all_raw_ledger_data().iter())?;
            }
            Self::Import {
                account,
                from,
                target,
            } => {
                let data = load_data(&mut fsdata, inv, Default::default())?;

                let aname = account.into();
                let Some(aspec) = data.account_spec(aname) else {
                    log::error!("Account {aname} does not exist!");
                    return Ok(());
                };

                let default_destination = data.spec_root().placeholder_account;

                let imported =
                    import::import_from(aspec, aname, default_destination, from.as_path()).unwrap();
                log::info!("Imported {} transaction(s)", imported.len());

                if let Some(target) = target {
                    let new_source = std::fs::canonicalize(target.as_os_str())?
                        .into_os_string()
                        .into();

                    let source_span = io::Span::null_for_file(new_source);

                    let new_data = imported
                        .into_iter()
                        .map(|mut txn| {
                            txn.source = Some(source_span);
                            data::RawLedgerEntry::Transaction(txn)
                        })
                        .collect_vec();

                    data::format_ledger(
                        &mut fsdata,
                        &data,
                        data.raw_ledger_data_from(new_source).chain(new_data.iter()),
                    )?;
                } else {
                    log::info!("No target specified, showing new data on stdout.");
                    let tt = show::TransactionTable::default();
                    tt.show(Some(&data), aname, imported.iter());
                }
            }
            Self::Infer => {
                let mut data = load_data(&mut fsdata, inv, check::CheckLevel::WellFormed)?;

                if infer::do_inference(&mut data)? {
                    data::format_entire_ledger(&mut fsdata, &data)?;
                }
            }
            Self::Match { account } => {
                let mut data = load_data(&mut fsdata, inv, check::CheckLevel::WellFormed)?;

                let account = account.unwrap_or(data.spec_root().placeholder_account);

                if txnmatch::do_match(&mut data, account)? {
                    data::format_entire_ledger(&mut fsdata, &data)?;
                }
            }
            Self::Comb { account } => {
                let data = load_data(&mut fsdata, inv, check::CheckLevel::Consistent)?;

                let account = account.unwrap_or(data.spec_root().placeholder_account);

                if comb::do_comb(&data, account)? {
                    data::format_entire_ledger(&mut fsdata, &data)?;
                }
            }
        }
        Ok(())
    }
}