use std::{
    fs,
    path::Path,
    cmp::{ min, max, },
};
use rust_util::{
    iff,
    XResult,
    new_box_ioerror,
    util_msg::*,
};
use chrono::Utc;

pub const NAME: &str = "oss-backupd";
pub const VERSION: &str = "1.0.0";

const DOT_OSS_BACKUPD_CONFIG: &str = ".oss-backupd-config.json";
const OSS_BACKUPD_CONFIG: &str = "oss-backupd-config.json";
const ETC_OSS_BACKUPD_CONFIG: &str = "/etc/oss-backupd/config.json";

/*
{
    "oss_config": {
        "endpoint": "",
        "access_key_id": "",
        "access_key_secret": "",
        "bucket": "",
        "path": ""
    },
    "host": "",
    "encrypt_pubkey_file": "",
    "backup_count": 10,
    "items": [
        {
            "oss_config": null, // OPT @oss_config
            "target": "",
            "file_name": "",
            "encrypt_pubkey_file": null, // OPT @encrypt_pubkey_file
            "backup_count": 8
        }
    ]
}
*/

#[derive(Debug, Clone)]
pub struct OSSConfig {
    pub endpoint: Option<String>,
    pub access_key_id: Option<String>,
    pub access_key_secret: Option<String>,
    pub bucket: Option<String>,
    pub path: Option<String>,
}

#[derive(Debug)]
pub struct OSSBackupdConfigItem {
    pub target: Option<String>,
    pub file_name: Option<String>,
    pub oss_config: Option<OSSConfig>,
    pub encrypt_pubkey_file: Option<String>,
    pub backup_count: Option<u32>,
}

#[derive(Debug)]
pub struct OSSBackupdConfig {
    pub oss_config: Option<OSSConfig>,
    pub prefix: Option<String>,
    pub host: Option<String>,
    pub items: Vec<OSSBackupdConfigItem>,
    pub backup_count: Option<u32>,
}

impl OSSBackupdConfig {

    pub fn get_host(&self) -> String {
        match &self.host {
            Some(h) => remove_start_end_slash(&h),
            None => "default_host".to_owned(),
        }
    }

    pub fn get_prefix(&self) -> String {
        match &self.prefix {
            Some(p) => remove_start_end_slash(&p),
            None => "default_oss_backupd".to_owned(),
        }
    }
}

impl OSSBackupdConfigItem {

    pub fn make_oss_key(&self, oss_backupd_config: &OSSBackupdConfig, suffix: &str) -> String {
        real_make_oss_key(oss_backupd_config, &self, suffix)
    }

    pub fn get_file_name(&self) -> String {
        match &self.file_name {
            Some(f) => f.clone(),
            None => "default_file_name".to_owned(),
        }
    }

    pub fn get_safe_backup_count(&self) -> usize {
        min(
            max(
                self.backup_count.unwrap_or(10u32) as usize,
                1_usize
            ),
            1000_usize
        )
    }
}

pub fn parse_config(config_json: &json::JsonValue) -> OSSBackupdConfig {
    let root_oss_config_object = parse_sub_oss_config(config_json);
    let encrypt_pubkey_file = get_string_value(config_json, "encrypt_pubkey_file");
    let prefix = get_string_value(config_json, "prefix");
    let host = get_string_value(config_json, "host");
    let backup_count = get_u32_value(config_json, "backup_count");
    let items = &config_json["items"];
    let mut items_objects: Vec<OSSBackupdConfigItem> = vec![];
    if items.is_array() {
        for i in 0..items.len() {
            items_objects.push(parse_oss_backupd_config_item(&items[i], &root_oss_config_object, &encrypt_pubkey_file, backup_count));
        }
    }

    OSSBackupdConfig {
        oss_config: root_oss_config_object,
        prefix,
        host,
        backup_count,
        items: items_objects,
    }
}

pub fn get_config_json(custom_oss_backupd_config: Option<&str>, verbose: bool) -> Option<json::JsonValue> {
    let config_content = get_config_content(custom_oss_backupd_config, verbose)?;
    match json::parse(&config_content) {
        Ok(o) => Some(o), Err(e) => {
            print_message(MessageType::ERROR, &format!("Parse config json failed: {}", e));
            None
        },
    }
}

fn remove_start_end_slash(s: &str) -> String {
    let mut ss = s;
    while ss.starts_with('/') {
        ss = &ss[1..]
    }
    while ss.ends_with('/') {
        ss = &ss[0..(ss.len() - 1)];
    }
    ss.to_owned()
}

fn parse_oss_backupd_config_item(item: &json::JsonValue, root_oss_config_object: &Option<OSSConfig>, root_encrypt_pubkey_file: &Option<String>, root_backup_count: Option<u32>) -> OSSBackupdConfigItem {
    let target = get_string_value(item, "target");
    let file_name = get_string_value(item, "file_name");
    let mut backup_count = get_u32_value(item, "backup_count");
    let mut encrypt_pubkey_file = get_string_value(item, "encrypt_pubkey_file");
    let mut oss_config = parse_sub_oss_config(item);
    if let Some(ref root_oc) = root_oss_config_object {
        match oss_config {
            Some(mut oc) => {
                if oc.endpoint.is_none() && root_oc.endpoint.is_some() {
                    oc.endpoint = root_oc.endpoint.clone()
                }
                if oc.access_key_id.is_none() && root_oc.access_key_id.is_some() {
                    oc.access_key_id = root_oc.access_key_id.clone()
                }
                if oc.access_key_secret.is_none() && root_oc.access_key_secret.is_some() {
                    oc.access_key_secret = root_oc.access_key_secret.clone();
                }
                if oc.bucket.is_none() && root_oc.bucket.is_some() {
                    oc.bucket = root_oc.bucket.clone();
                }
                if oc.path.is_none() && root_oc.path.is_some() {
                    oc.path = root_oc.path.clone();
                }
                oss_config = Some(oc);
            },
            None => oss_config = root_oss_config_object.clone(),
        }
    }

    if encrypt_pubkey_file.is_none() && root_encrypt_pubkey_file.is_some() {
        encrypt_pubkey_file = root_encrypt_pubkey_file.clone();
    }
    if backup_count.is_none() && root_backup_count.is_some() {
        backup_count = root_backup_count;
    }

    OSSBackupdConfigItem {
        target,
        file_name,
        oss_config,
        backup_count,
        encrypt_pubkey_file,
    }
}

fn real_make_oss_key(oss_backupd_config: &OSSBackupdConfig, oss_backupd_config_item: &OSSBackupdConfigItem, suffix: &str) -> String {
    let mut key = String::with_capacity(1024);
    key.push_str(&oss_backupd_config.get_prefix());
    key.push_str("/");
    key.push_str(&oss_backupd_config.get_host());
    key.push_str("/");
    key.push_str(&format!("{}_{}", &oss_backupd_config_item.get_file_name(), &get_now_ymdhms()));

    if !suffix.is_empty() {
        key.push_str(&format!(".{}", suffix));
    }

    key
}

fn parse_sub_oss_config(json: &json::JsonValue) -> Option<OSSConfig> {
    let root_oss_config = &json["oss_config"];
    iff!(root_oss_config.is_null(), None, Some(parse_oss_config(root_oss_config)))
}

fn parse_oss_config(oss_config: &json::JsonValue) -> OSSConfig {
    OSSConfig {
        endpoint: get_string_value(oss_config, "endpoint"),
        access_key_id: get_string_value(oss_config, "access_key_id"),
        access_key_secret: get_string_value(oss_config, "access_key_secret"),
        bucket: get_string_value(oss_config, "bucket"),
        path: get_string_value(oss_config, "path"),
    }
}

fn get_string_value(json: &json::JsonValue, key: &str) -> Option<String> {
    let value = &json[key];
    value.as_str().map(|s| s.to_owned())
}

fn get_u32_value(json: &json::JsonValue, key: &str) -> Option<u32> {
    let value = &json[key];
    match value {
        json::JsonValue::String(v) => v.parse().ok(),
        json::JsonValue::Number(v) => Some(f64::from(*v) as u32),
        _ => None,
    }
}

fn get_config_content(custom_oss_backupd_config: Option<&str>, verbose: bool) -> Option<String> {
    if let Some(custom_oss_backupd_config_val) = custom_oss_backupd_config {
        if verbose  {
            print_message(MessageType::DEBUG, &format!("Read config from: {}", custom_oss_backupd_config_val));
        }
        let custom_oss_backupd_config_path = Path::new(custom_oss_backupd_config_val);
        if custom_oss_backupd_config_path.exists() {
            return match fs::read_to_string(custom_oss_backupd_config_path) {
                Ok(o) => Some(o), Err(e) => {
                    print_message(MessageType::ERROR, &format!("Read config file {} error: {}", custom_oss_backupd_config_val, e));
                    None
                },
            };
        } else {
            print_message(MessageType::ERROR, &format!("Custom config file not found: {}", custom_oss_backupd_config_val));
            return None;
        }
    }
    // is not assigned by -c or --conifg FILE
    let oss_backupd_config_path = Path::new(OSS_BACKUPD_CONFIG);
    if oss_backupd_config_path.exists() {
        if verbose {
            print_message(MessageType::DEBUG, &format!("Read config from: {}", OSS_BACKUPD_CONFIG));
        }
        return match fs::read_to_string(oss_backupd_config_path) {
            Ok(o) => Some(o), Err(e) => {
                print_message(MessageType::ERROR, &format!("Read config file {} error: {}", OSS_BACKUPD_CONFIG, e));
                None
            },
        };
    }
    let home_dot_oss_backupd_config = & match get_user_home_dir(DOT_OSS_BACKUPD_CONFIG) {
        Ok(o) => o, Err(e) => {
            print_message(MessageType::WARN, &format!("Get user home error: {}", e));
            String::new()
        },
    };
    if !home_dot_oss_backupd_config.is_empty() {
        let home_dot_oss_backupd_config_path = Path::new(home_dot_oss_backupd_config);
        if home_dot_oss_backupd_config_path.exists() {
            if verbose {
                print_message(MessageType::DEBUG, &format!("Read config from: {}", home_dot_oss_backupd_config));
            }
            return match fs::read_to_string(home_dot_oss_backupd_config_path) {
                Ok(o) => Some(o), Err(e) => {
                    print_message(MessageType::ERROR, &format!("Read config file {} error: {}", home_dot_oss_backupd_config, e));
                    None
                },
            };
        }
    }
    let etc_oss_backupd_config_path = Path::new(ETC_OSS_BACKUPD_CONFIG);
    if etc_oss_backupd_config_path.exists() {
        if verbose {
            print_message(MessageType::DEBUG, &format!("Read config from: {}", ETC_OSS_BACKUPD_CONFIG));
        }
        return match fs::read_to_string(etc_oss_backupd_config_path) {
            Ok(o) => Some(o), Err(e) => {
                print_message(MessageType::ERROR, &format!("Read config file {} error: {}", ETC_OSS_BACKUPD_CONFIG, e));
                None
            },
        };
    }

    print_message(MessageType::ERROR, "Cannot find config file");
    None
}

fn get_user_home() -> XResult<String> {
    match dirs::home_dir() {
         None => Err(new_box_ioerror("Home dir not found!")),
         Some(home_dir) => home_dir.to_str().map(|h| h.to_owned()).ok_or_else(|| new_box_ioerror("Home dir not found!")),
     }
 }
 
fn get_user_home_dir(dir: &str) -> XResult<String> {
     Ok(format!("{}/{}", get_user_home()?, dir))
 }

fn get_now_ymdhms() -> String {
    Utc::now().format("%Y%m%d_%H%M%S").to_string()
}