use std::collections::HashMap;
use json::{object};

use crate::lightclient::LightClient;

pub trait Command {
    fn help(&self) -> String;

    fn short_help(&self) -> String;

    fn exec(&self, _args: &[&str], lightclient: &LightClient) -> String;
}

struct SyncCommand {}
impl Command for SyncCommand {
    fn help(&self) -> String {
        let mut h = vec![];
        h.push("Sync the light client with the server");
        h.push("Usage:");
        h.push("sync");
        h.push("");

        h.join("\n")
    }

    fn short_help(&self) -> String {
        "Download CompactBlocks and sync to the server".to_string()
    }

    fn exec(&self, _args: &[&str], lightclient: &LightClient) -> String {
        match lightclient.do_sync(true) {
            Ok(j) => j.pretty(2),
            Err(e) => e
        }
    }
}

struct EncryptionStatusCommand {}
impl Command for EncryptionStatusCommand {
    fn help(&self) -> String {
        let mut h = vec![];
        h.push("Check if the wallet is encrypted and if it is locked");
        h.push("Usage:");
        h.push("encryptionstatus");
        h.push("");

        h.join("\n")
    }

    fn short_help(&self) -> String {
        "Check if the wallet is encrypted and if it is locked".to_string()
    }

    fn exec(&self, _args: &[&str], lightclient: &LightClient) -> String {
        lightclient.do_encryption_status().pretty(2)
    }
}

struct SyncStatusCommand {}
impl Command for SyncStatusCommand {
    fn help(&self) -> String {
        let mut h = vec![];
        h.push("Get the sync status of the wallet");
        h.push("Usage:");
        h.push("syncstatus");
        h.push("");

        h.join("\n")
    }

    fn short_help(&self) -> String {
        "Get the sync status of the wallet".to_string()
    }

    fn exec(&self, _args: &[&str], lightclient: &LightClient) -> String {
        let status = lightclient.do_scan_status();
        match status.is_syncing {
            false => object!{ "syncing" => "false" },
            true  => object!{ "syncing" => "true",
                              "synced_blocks" => status.synced_blocks,
                              "total_blocks" => status.total_blocks } 
        }.pretty(2)
    }
}

struct RescanCommand {}
impl Command for RescanCommand {
    fn help(&self) -> String {
        let mut h = vec![];
        h.push("Rescan the wallet, rescanning all blocks for new transactions");
        h.push("Usage:");
        h.push("rescan");
        h.push("");
        h.push("This command will download all blocks since the intial block again from the light client server");
        h.push("and attempt to scan each block for transactions belonging to the wallet.");

        h.join("\n")
    }

    fn short_help(&self) -> String {
        "Rescan the wallet, downloading and scanning all blocks and transactions".to_string()
    }

    fn exec(&self, _args: &[&str], lightclient: &LightClient) -> String {
        match lightclient.do_rescan() {
            Ok(j) => j.pretty(2),
            Err(e) => e
        }
    }
}


struct HelpCommand {}
impl Command for HelpCommand {
    fn help(&self) -> String {
        let mut h = vec![];
        h.push("List all available commands");
        h.push("Usage:");
        h.push("help [command_name]");
        h.push("");
        h.push("If no \"command_name\" is specified, a list of all available commands is returned");
        h.push("Example:");
        h.push("help send");
        h.push("");

        h.join("\n")
    }

    fn short_help(&self) -> String {
        "Lists all available commands".to_string()
    }

    fn exec(&self, args: &[&str], _: &LightClient) -> String {
        let mut responses = vec![];

        // Print a list of all commands
        match args.len() {
            0 => {
                responses.push(format!("Available commands:"));
                get_commands().iter().for_each(| (cmd, obj) | {
                    responses.push(format!("{} - {}", cmd, obj.short_help()));
                });

                responses.join("\n")
            },
            1 => {
                match get_commands().get(args[0]) {
                    Some(cmd) => cmd.help(),
                    None => format!("Command {} not found", args[0])
                }
            },
            _ => self.help()
        }
    }
}

struct InfoCommand {}
impl Command for InfoCommand {
    fn help(&self) -> String {
        let mut h = vec![];
        h.push("Get info about the lightwalletd we're connected to");
        h.push("Usage:");
        h.push("info");
        h.push("");

        h.join("\n")
    }

    fn short_help(&self) -> String {
        "Get the lightwalletd server's info".to_string()
    }

    fn exec(&self, _args: &[&str], lightclient: &LightClient) -> String {        
        lightclient.do_info()
    }
}

struct BalanceCommand {}
impl Command for BalanceCommand {
    fn help(&self) -> String {
        let mut h = vec![];
        h.push("Show the current HUSH balance in the wallet");
        h.push("Usage:");
        h.push("balance");
        h.push("");
        h.push("Transparent and Shielded balances, along with the addresses they belong to are displayed");

        h.join("\n")
    }

    fn short_help(&self) -> String {
        "Show the current HUSH balance in the wallet".to_string()
    }

    fn exec(&self, _args: &[&str], lightclient: &LightClient) -> String {
        match lightclient.do_sync(true) {
            Ok(_) => format!("{}", lightclient.do_balance().pretty(2)),
            Err(e) => e
        }
    }
}


struct AddressCommand {}
impl Command for AddressCommand {
    fn help(&self) -> String {
        let mut h = vec![];
        h.push("List current addresses in the wallet");
        h.push("Usage:");
        h.push("address");
        h.push("");

        h.join("\n")
    }

    fn short_help(&self) -> String {
        "List all addresses in the wallet".to_string()
    }

    fn exec(&self, _args: &[&str], lightclient: &LightClient) -> String {
        format!("{}", lightclient.do_address().pretty(2))
    }
}

struct ExportCommand {}
impl Command for ExportCommand {
    fn help(&self) -> String {
        let mut h = vec![];
        h.push("Export private key for an individual wallet addresses.");
        h.push("Note: To backup the whole wallet, use the 'seed' command insted");
        h.push("Usage:");
        h.push("export [t-address or z-address]");
        h.push("");
        h.push("If no address is passed, private key for all addresses in the wallet are exported.");
        h.push("");
        h.push("Example:");
        h.push("export ztestsapling1x65nq4dgp0qfywgxcwk9n0fvm4fysmapgr2q00p85ju252h6l7mmxu2jg9cqqhtvzd69jwhgv8d");

        h.join("\n")
    }

    fn short_help(&self) -> String {
        "Export private key for wallet addresses".to_string()
    }

    fn exec(&self, args: &[&str], lightclient: &LightClient) -> String {
        if args.len() > 1 {
            return self.help();
        }

        let address = if args.is_empty() { None } else { Some(args[0].to_string()) };
        match lightclient.do_export(address) {
            Ok(j)  => j,
            Err(e) => object!{ "error" => e }
        }.pretty(2)
    }
}

struct EncryptCommand {}
impl Command for EncryptCommand {
    fn help(&self) -> String {
        let mut h = vec![];
        h.push("Encrypt the wallet with a password");
        h.push("Note 1: This will encrypt the seed and the sapling and transparent private keys.");
        h.push("        Use 'unlock' to temporarily unlock the wallet for spending or 'decrypt' ");
        h.push("        to permanatly remove the encryption");
        h.push("Note 2: If you forget the password, the only way to recover the wallet is to restore");
        h.push("        from the seed phrase.");
        h.push("Usage:");
        h.push("encrypt password");
        h.push("");
        h.push("Example:");
        h.push("encrypt my_strong_password");

        h.join("\n")
    }

    fn short_help(&self) -> String {
        "Encrypt the wallet with a password".to_string()
    }

    fn exec(&self, args: &[&str], lightclient: &LightClient) -> String {
        if args.len() != 1 {
            return self.help();
        }

        // Refuse to encrypt if the bip39 bug has not been fixed
        use crate::lightwallet::bugs::BugBip39Derivation;
        if BugBip39Derivation::has_bug(lightclient) {
            let mut h = vec![];
            h.push("It looks like your wallet has the bip39bug. Please run 'fixbip39bug' to fix it");
            h.push("before encrypting your wallet.");
            h.push("ERROR: Cannot encrypt while wallet has the bip39bug.");
            return h.join("\n");
        }

        let passwd = args[0].to_string();

        match lightclient.wallet.write().unwrap().encrypt(passwd) {
            Ok(_)  => object!{ "result" => "success" },
            Err(e) => object!{
                "result" => "error",
                "error"  => e.to_string()
            }
        }.pretty(2)
    }
}

struct DecryptCommand {}
impl Command for DecryptCommand {
    fn help(&self) -> String {
        let mut h = vec![];
        h.push("Completely remove wallet encryption, storing the wallet in plaintext on disk");
        h.push("Note 1: This will decrypt the seed and the sapling and transparent private keys and store them on disk.");
        h.push("        Use 'unlock' to temporarily unlock the wallet for spending");
        h.push("Note 2: If you've forgotten the password, the only way to recover the wallet is to restore");
        h.push("        from the seed phrase.");
        h.push("Usage:");
        h.push("decrypt password");
        h.push("");
        h.push("Example:");
        h.push("decrypt my_strong_password");

        h.join("\n")
    }

    fn short_help(&self) -> String {
        "Completely remove wallet encryption".to_string()
    }

    fn exec(&self, args: &[&str], lightclient: &LightClient) -> String {
        if args.len() != 1 {
            return self.help();
        }

        let passwd = args[0].to_string();

        match lightclient.wallet.write().unwrap().remove_encryption(passwd) {
            Ok(_)  => object!{ "result" => "success" },
            Err(e) => object!{
                "result" => "error",
                "error"  => e.to_string()
            }
        }.pretty(2)
    }
}


struct UnlockCommand {}
impl Command for UnlockCommand {
    fn help(&self) -> String {
        let mut h = vec![];
        h.push("Unlock the wallet's encryption in memory, allowing spending from this wallet.");
        h.push("Note 1: This will decrypt spending keys in memory only. The wallet remains encrypted on disk");
        h.push("        Use 'decrypt' to remove the encryption permanatly.");
        h.push("Note 2: If you've forgotten the password, the only way to recover the wallet is to restore");
        h.push("        from the seed phrase.");
        h.push("Usage:");
        h.push("unlock password");
        h.push("");
        h.push("Example:");
        h.push("unlock my_strong_password");

        h.join("\n")
    }

    fn short_help(&self) -> String {
        "Unlock wallet encryption for spending".to_string()
    }

    fn exec(&self, args: &[&str], lightclient: &LightClient) -> String {
        if args.len() != 1 {
            return self.help();
        }

        let passwd = args[0].to_string();

        match lightclient.wallet.write().unwrap().unlock(passwd) {
            Ok(_)  => object!{ "result" => "success" },
            Err(e) => object!{
                "result" => "error",
                "error"  => e.to_string()
            }
        }.pretty(2)
    }
}


struct LockCommand {}
impl Command for LockCommand {
    fn help(&self) -> String {
        let mut h = vec![];
        h.push("Lock a wallet that's been temporarily unlocked. You should already have encryption enabled.");
        h.push("Note 1: This will remove all spending keys from memory. The wallet remains encrypted on disk");
        h.push("Note 2: If you've forgotten the password, the only way to recover the wallet is to restore");
        h.push("        from the seed phrase.");
        h.push("Usage:");
        h.push("lock");
        h.push("");
        h.push("Example:");
        h.push("lock");

        h.join("\n")
    }

    fn short_help(&self) -> String {
        "Lock a wallet that's been temporarily unlocked".to_string()
    }

    fn exec(&self, args: &[&str], lightclient: &LightClient) -> String {
        if args.len() != 0 {
            let mut h = vec![];
            h.push("Extra arguments to lock. Did you mean 'encrypt'?");
            h.push("");
            
            return format!("{}\n{}", h.join("\n"), self.help());
        }

        match lightclient.wallet.write().unwrap().lock() {
            Ok(_)  => object!{ "result" => "success" },
            Err(e) => object!{
                "result" => "error",
                "error"  => e.to_string()
            }
        }.pretty(2)
    }
}


struct SendCommand {}
impl Command for SendCommand {
    fn help(&self) -> String {
        let mut h = vec![];
        h.push("Send HUSH to a given address");
        h.push("Usage:");
        h.push("send <address> <amount in puposhis> \"optional_memo\"");
        h.push("OR");
        h.push("send '[{'address': <address>, 'amount': <amount in puposhis>, 'memo': <optional memo>}, ...]'");
        h.push("");
        h.push("Example:");
        h.push("send ztestsapling1x65nq4dgp0qfywgxcwk9n0fvm4fysmapgr2q00p85ju252h6l7mmxu2jg9cqqhtvzd69jwhgv8d 200000 \"Hello from the command line\"");
        h.push("");

        h.join("\n")
    }

    fn short_help(&self) -> String {
        "Send HUSH to the given address".to_string()
    }

    fn exec(&self, args: &[&str], lightclient: &LightClient) -> String {
        // Parse the args. There are two argument types.
        // 1 - A set of 2(+1 optional) arguments for a single address send representing address, value, memo?
        // 2 - A single argument in the form of a JSON string that is "[{address: address, value: value, memo: memo},...]"

        // 1 - Destination address. T or Z address
         if args.len() < 1 || args.len() > 3 {
            return self.help();
        }

        // Check for a single argument that can be parsed as JSON
        let send_args = if args.len() == 1 {
            let arg_list = args[0];

            let json_args = match json::parse(&arg_list) {
                Ok(j)  => j,
                Err(e) => {
                    let es = format!("Couldn't understand JSON: {}", e);
                    return format!("{}\n{}", es, self.help());
                }
            };

         if !json_args.is_array() {
                return format!("Couldn't parse argument as array\n{}", self.help());
            }

                    let maybe_send_args = json_args.members().map( |j| {
                if !j.has_key("address") || !j.has_key("amount") {
                    Err(format!("Need 'address' and 'amount'\n"))
                } else {
                    Ok((j["address"].as_str().unwrap().to_string().clone(), j["amount"].as_u64().unwrap(), j["memo"].as_str().map(|s| s.to_string().clone())))
                }
            }).collect::<Result<Vec<(String, u64, Option<String>)>, String>>();

            match maybe_send_args {
                Ok(a) => a.clone(),
                Err(s) => { return format!("Error: {}\n{}", s, self.help()); }
            }
        } else if args.len() == 2 || args.len() == 3 {
            // Make sure we can parse the amount
            let value = match args[1].parse::<u64>() {
                Ok(amt) => amt,
                Err(e)  => {
                    return format!("Couldn't parse amount: {}", e);
                }
            };

            let memo = if args.len() == 3 { Some(args[2].to_string()) } else {None};
            
            vec![(args[0].to_string(), value, memo)]
        } else {
            return self.help()
        };

        match lightclient.do_sync(true) {
            Ok(_) => {
                // Convert to the right format. String -> &str.
                let tos = send_args.iter().map(|(a, v, m)| (a.as_str(), *v, m.clone()) ).collect::<Vec<_>>();
                match lightclient.do_send(tos) {
                    Ok(txid) => { object!{ "txid" => txid } },
                    Err(e)   => { object!{ "error" => e } }
                }.pretty(2)
            },
            Err(e) => e
        }
    }
}

struct SaveCommand {}
impl Command for SaveCommand {
    fn help(&self) -> String {
        let mut h = vec![];
        h.push("Save the wallet to disk");
        h.push("Usage:");
        h.push("save");
        h.push("");
        h.push("The wallet is saved to disk. The wallet is periodically saved to disk (and also saved upon exit)");
        h.push("but you can use this command to explicitly save it to disk");

        h.join("\n")
    }

    fn short_help(&self) -> String {
        "Save wallet file to disk".to_string()
    }

    fn exec(&self, _args: &[&str], lightclient: &LightClient) -> String {
        match lightclient.do_save() {
            Ok(_) => {
                let r = object!{ "result" => "success" };
                r.pretty(2)
            },
            Err(e) => {
                let r = object!{ 
                    "result" => "error",
                    "error" => e 
                };
                r.pretty(2)
            }
        }
    }
}

struct SeedCommand {}
impl Command for SeedCommand {
    fn help(&self) -> String {
        let mut h = vec![];
        h.push("Show the wallet's seed phrase");
        h.push("Usage:");
        h.push("seed");
        h.push("");
        h.push("Your wallet is entirely recoverable from the seed phrase. Please save it carefully and don't share it with anyone");

        h.join("\n")
    }

    fn short_help(&self) -> String {
        "Display the seed phrase".to_string()
    }

    fn exec(&self, _args: &[&str], lightclient: &LightClient) -> String {
        match lightclient.do_seed_phrase() {
            Ok(j)  => j,
            Err(e) => object!{ "error" => e }
        }.pretty(2)
    }
}

struct TransactionsCommand {}
impl Command for TransactionsCommand {
    fn help(&self)  -> String {
        let mut h = vec![];
        h.push("List all incoming and outgoing transactions from this wallet");
        h.push("Usage:");
        h.push("list");
        h.push("");

        h.join("\n")
    }

    fn short_help(&self) -> String {
        "List all transactions in the wallet".to_string()
    }

    fn exec(&self, _args: &[&str], lightclient: &LightClient) -> String {
        match lightclient.do_sync(true) {
            Ok(_) => {
                format!("{}", lightclient.do_list_transactions().pretty(2))
            },
            Err(e) => e
        }
    }
}

struct HeightCommand {}
impl Command for HeightCommand {
    fn help(&self)  -> String {
        let mut h = vec![];
        h.push("Get the latest block height that the wallet is at");
        h.push("Usage:");
        h.push("height");
        h.push("");

        h.join("\n")
    }

    fn short_help(&self) -> String {
        "Get the latest block height that the wallet is at".to_string()
    }

    fn exec(&self, _args: &[&str], lightclient: &LightClient) -> String {
        format!("{}",
            object! {
                "height" => lightclient.last_scanned_height()
            }.pretty(2))
    }
}


struct NewAddressCommand {}
impl Command for NewAddressCommand {
    fn help(&self)  -> String {
        let mut h = vec![];
        h.push("Create a new address in this wallet");
        h.push("Usage:");
        h.push("new [z | t]");
        h.push("");
        h.push("Example:");
        h.push("To create a new z address:");
        h.push("new z");
        h.join("\n")
    }

    fn short_help(&self) -> String {
        "Create a new address in this wallet".to_string()
    }

    fn exec(&self, args: &[&str], lightclient: &LightClient) -> String {
        if args.len() != 1 {
            return format!("No address type specified\n{}", self.help());
        }

        match lightclient.do_new_address(args[0]) {
            Ok(j)  => j,
            Err(e) => object!{ "error" => e }
        }.pretty(2)
    }
}

struct NotesCommand {}
impl Command for NotesCommand {
    fn help(&self)  -> String {
        let mut h = vec![];
        h.push("Show all sapling notes and utxos in this wallet");
        h.push("Usage:");
        h.push("notes [all]");
        h.push("");
        h.push("If you supply the \"all\" parameter, all previously spent sapling notes and spent utxos are also included");

        h.join("\n")
    }

    fn short_help(&self) -> String {
        "List all sapling notes and utxos in the wallet".to_string()
    }

    fn exec(&self, args: &[&str], lightclient: &LightClient) -> String {
        // Parse the args. 
        if args.len() > 1 {
            return self.short_help();
        }

        // Make sure we can parse the amount
        let all_notes = if args.len() == 1 {
            match args[0] {
                "all" => true,
                a     => return format!("Invalid argument \"{}\". Specify 'all' to include unspent notes", a)
            }
        } else {
            false
        };

        match lightclient.do_sync(true) {
            Ok(_) => {
                format!("{}", lightclient.do_list_notes(all_notes).pretty(2))
            },
            Err(e) => e
        }
    }
}

struct FixBip39BugCommand {}
impl Command for FixBip39BugCommand {
    fn help(&self)  -> String {
        let mut h = vec![];
        h.push("Detect if the wallet has the Bip39 derivation bug, and fix it automatically");
        h.push("Usage:");
        h.push("fixbip39bug");
        h.push("");

        h.join("\n")
    }

    fn short_help(&self) -> String {
        "Detect if the wallet has the Bip39 derivation bug, and fix it automatically".to_string()
    }

    fn exec(&self, _args: &[&str], lightclient: &LightClient) -> String {
        use crate::lightwallet::bugs::BugBip39Derivation;

        BugBip39Derivation::fix_bug(lightclient)
    }
}

struct QuitCommand {}
impl Command for QuitCommand {
    fn help(&self)  -> String {
        let mut h = vec![];
        h.push("Save the wallet to disk and quit");
        h.push("Usage:");
        h.push("quit");
        h.push("");

        h.join("\n")
    }

    fn short_help(&self) -> String {
        "Quit the lightwallet, saving state to disk".to_string()
    }

    fn exec(&self, _args: &[&str], lightclient: &LightClient) -> String {
        match lightclient.do_save() {
            Ok(_) => {"".to_string()},
            Err(e) => e
        }
    }
}

pub fn get_commands() -> Box<HashMap<String, Box<dyn Command>>> {
    let mut map: HashMap<String, Box<dyn Command>> = HashMap::new();

    map.insert("sync".to_string(),              Box::new(SyncCommand{}));
    map.insert("syncstatus".to_string(),        Box::new(SyncStatusCommand{}));
    map.insert("encryptionstatus".to_string(),  Box::new(EncryptionStatusCommand{}));
    map.insert("rescan".to_string(),            Box::new(RescanCommand{}));
    map.insert("help".to_string(),              Box::new(HelpCommand{}));
    map.insert("balance".to_string(),           Box::new(BalanceCommand{}));
    map.insert("addresses".to_string(),         Box::new(AddressCommand{}));
    map.insert("height".to_string(),            Box::new(HeightCommand{}));
    map.insert("export".to_string(),            Box::new(ExportCommand{}));
    map.insert("info".to_string(),              Box::new(InfoCommand{}));
    map.insert("send".to_string(),              Box::new(SendCommand{}));
    map.insert("save".to_string(),              Box::new(SaveCommand{}));
    map.insert("quit".to_string(),              Box::new(QuitCommand{}));
    map.insert("list".to_string(),              Box::new(TransactionsCommand{}));
    map.insert("notes".to_string(),             Box::new(NotesCommand{}));
    map.insert("new".to_string(),               Box::new(NewAddressCommand{}));
    map.insert("seed".to_string(),              Box::new(SeedCommand{}));
    map.insert("encrypt".to_string(),           Box::new(EncryptCommand{}));
    map.insert("decrypt".to_string(),           Box::new(DecryptCommand{}));
    map.insert("unlock".to_string(),            Box::new(UnlockCommand{}));
    map.insert("lock".to_string(),              Box::new(LockCommand{}));
    map.insert("fixbip39bug".to_string(),       Box::new(FixBip39BugCommand{}));

    Box::new(map)
}

pub fn do_user_command(cmd: &str, args: &Vec<&str>, lightclient: &LightClient) -> String {
    match get_commands().get(&cmd.to_ascii_lowercase()) {
        Some(cmd) => cmd.exec(args, lightclient),
        None      => format!("Unknown command : {}. Type 'help' for a list of commands", cmd)
    }
}




#[cfg(test)]
pub mod tests {
    use lazy_static::lazy_static;
    use super::do_user_command;
    use crate::lightclient::{LightClient};

    lazy_static!{
        static ref TEST_SEED: String = "youth strong sweet gorilla hammer unhappy congress stamp left stereo riot salute road tag clean toilet artefact fork certain leopard entire civil degree wonder".to_string();
    }

    #[test]
    pub fn test_command_caseinsensitive() {
        let lc = LightClient::unconnected(TEST_SEED.to_string(), None).unwrap();

        assert_eq!(do_user_command("addresses", &vec![], &lc),
                   do_user_command("AddReSSeS", &vec![], &lc));
                assert_eq!(do_user_command("addresses", &vec![], &lc),
                   do_user_command("Addresses", &vec![], &lc));
    }

    #[test]
    pub fn test_nosync_commands() {
        // The following commands should run 
    }
}