use serde_json::Value;

use std::{
    fs,
    env,
    path::PathBuf,
    time::SystemTime,
    io::{
        Error,
        ErrorKind,
    },
};
use sha2::Sha256;
use hmac::{
    Hmac,
    Mac,
};

mod msg;
use msg::*;

pub use msg:: {
    DingTalkMessage,
    DingTalkMessageType,
    DingTalkMessageActionCardHideAvatar,
    DingTalkMessageActionCardBtnOrientation,
    DingTalkMessageActionCardBtn,
    DingTalkMessageFeedCardLink,
};

pub type XResult<T> = Result<T, Box<dyn std::error::Error>>;

const CONTENT_TYPE: &str = "Content-Type";
const APPLICATION_JSON_UTF8: &str = "application/json; charset=utf-8";

const DEFAULT_DINGTALK_ROBOT_URL: &str = "https://oapi.dingtalk.com/robot/send";

/// `DingTalk` is a simple SDK for DingTalk webhook robot
/// 
/// Document https://ding-doc.dingtalk.com/doc#/serverapi2/qf2nxq
/// 
/// Sample code:
/// ```
/// let dt = DingTalk::new("<token>", "");
/// dt.send_text("Hello world!")?;
/// ```
/// 
/// At all sample:
/// ```
/// dt.send_message(&DingTalkMessage::new_text("Hello World!").at_all())?;
/// ```
#[derive(Default)]
pub struct DingTalk<'a> {
    pub default_webhook_url: &'a str,
    pub access_token: &'a str,
    pub sec_token: &'a str,
    pub direct_url: &'a str,
}

impl <'a> DingTalkMessage<'a> {

    /// New text DingTalk message
    pub fn new_text(text_content: &'a str) -> Self {
        Self::new(DingTalkMessageType::Text).text(text_content)
    }

    /// New markdown DingTalk message
    pub fn new_markdown(markdown_title: &'a str, markdown_content: &'a str) -> Self {
        Self::new(DingTalkMessageType::Markdown).markdown(markdown_title, markdown_content)
    }

    /// New link DingTalk message
    pub fn new_link(link_title: &'a str, link_text: &'a str, link_pic_url: &'a str, link_message_url: &'a str) -> Self {
        Self::new(DingTalkMessageType::Link).link(link_title, link_text, link_pic_url, link_message_url)
    }

    /// New action card DingTalk message
    pub fn new_action_card(title: &'a str, text: &'a str) -> Self {
        let mut s = Self::new(DingTalkMessageType::ActionCard);
        s.action_card_title = title;
        s.action_card_text = text;
        s
    }

    /// New feed card DingTalk message
    pub fn new_feed_card() -> Self {
        Self::new(DingTalkMessageType::FeedCard)
    }
    
    /// New DingTalk message
    pub fn new(message_type: DingTalkMessageType) -> Self {
        DingTalkMessage {
            message_type,
            ..Default::default()
        }
    }

    /// Set text
    pub fn text(mut self, text_content: &'a str) -> Self {
        self.text_content = text_content;
        self
    }

    /// Set markdown
    pub fn markdown(mut self, markdown_title: &'a str, markdown_content: &'a str) -> Self {
        self.markdown_title = markdown_title;
        self.markdown_content = markdown_content;
        self
    }

    /// Set link
    pub fn link(mut self, link_title: &'a str, link_text: &'a str, link_pic_url: &'a str, link_message_url: &'a str) -> Self {
        self.link_title = link_title;
        self.link_text = link_text;
        self.link_pic_url = link_pic_url;
        self.link_message_url = link_message_url;
        self
    }

    /// Set action card show avator(default show)
    pub fn action_card_show_avatar(mut self) -> Self {
        self.action_card_hide_avatar = DingTalkMessageActionCardHideAvatar::Show;
        self
    }

    /// Set action card hide avator
    pub fn action_card_hide_avatar(mut self) -> Self {
        self.action_card_hide_avatar = DingTalkMessageActionCardHideAvatar::Hide;
        self
    }

    /// Set action card btn vertical(default vertical)
    pub fn action_card_btn_vertical(mut self) -> Self {
        self.action_card_btn_orientation = DingTalkMessageActionCardBtnOrientation::Vertical;
        self
    }

    /// Set action card btn landscape
    pub fn action_card_btn_landscape(mut self) -> Self {
        self.action_card_btn_orientation = DingTalkMessageActionCardBtnOrientation::Landscape;
        self
    }

    /// Set action card single btn
    pub fn set_action_card_signle_btn(mut self, btn: DingTalkMessageActionCardBtn) -> Self {
        self.action_card_single_btn = Some(btn);
        self
    }

    /// Add action card btn
    pub fn add_action_card_btn(mut self, btn: DingTalkMessageActionCardBtn) -> Self {
        self.action_card_btns.push(btn);
        self
    }
    
    /// Add feed card link
    pub fn add_feed_card_link(mut self, link: DingTalkMessageFeedCardLink) -> Self {
        self.feed_card_links.push(link);
        self
    }

    /// Add feed card link detail
    pub fn add_feed_card_link_detail(self, title: &'a str, message_url: &'a str, pic_url: &'a str) -> Self {
        self.add_feed_card_link(DingTalkMessageFeedCardLink {
            title: title.into(),
            message_url: message_url.into(),
            pic_url: pic_url.into(),
        })
    }

    /// At all
    pub fn at_all(mut self) -> Self {
        self.at_all = true;
        self
    }

    /// At mobiles
    pub fn at_mobiles(mut self, mobiles: &[String]) -> Self {
        for m in mobiles {
            self.at_mobiles.push(m.clone());
        }
        self
    }
}

impl <'a> DingTalk<'a> {

    /// Create `DingTalk` from file
    /// 
    /// Format see `DingTalk::from_json(json: &str)`
    pub fn from_file(f: &str) -> XResult<Self> {
        let f_path_buf = if f.starts_with("~/") {
            let home = PathBuf::from(env::var("HOME")?);
            home.join(f.chars().skip(2).collect::<String>())
        } else {
            PathBuf::from(f)
        };
        let f_content = fs::read_to_string(f_path_buf)?;
        Self::from_json(&f_content)
    }

    /// Create `DingTalk` from JSON string
    /// 
    /// Format:
    /// ```json
    /// {
    ///     "default_webhook_url": "", // option
    ///     "access_token": "<access token>",
    ///     "sec_token": "<sec token>" // option
    /// }
    /// ```
    pub fn from_json(json: &str) -> XResult<Self> {
        let json_value: Value = serde_json::from_str(json)?;
        if !json_value.is_object() {
            return Err(Box::new(Error::new(ErrorKind::Other, format!("JSON format erorr: {}", json))));
        }

        let default_webhook_url = Self::string_to_a_str(json_value["default_webhook_url"].as_str().unwrap_or(DEFAULT_DINGTALK_ROBOT_URL));
        let access_token = Self::string_to_a_str(json_value["access_token"].as_str().unwrap_or_default());
        let sec_token = Self::string_to_a_str(json_value["sec_token"].as_str().unwrap_or_default());
        let direct_url = Self::string_to_a_str(json_value["direct_url"].as_str().unwrap_or_default());
        
        Ok(DingTalk {
            default_webhook_url,
            access_token,
            sec_token,
            direct_url,
        })
    }

    /// Create `DingTalk` from url, for outgoing robot
    pub fn from_url(direct_url: &'a str) -> Self {
        DingTalk {
            direct_url,
            ..Default::default()
        }
    }

    /// Create `DingTalk`
    /// `access_token` is access token, `sec_token` can be empty `""`
    pub fn new(access_token: &'a str, sec_token: &'a str) -> Self {
        DingTalk {
            default_webhook_url: DEFAULT_DINGTALK_ROBOT_URL,
            access_token,
            sec_token,
            ..Default::default()
        }
    }

    /// Set default webhook url
    pub fn set_default_webhook_url(&mut self, default_webhook_url: &'a str) {
        self.default_webhook_url = default_webhook_url;
    }

    /// Send DingTalk message
    /// 
    /// 1. Create DingTalk JSON message
    /// 2. POST JSON message to DingTalk server
    pub async fn send_message(&self, dingtalk_message: &DingTalkMessage<'_>) -> XResult<()> {
        let mut message_json = match dingtalk_message.message_type {
            DingTalkMessageType::Text => serde_json::to_value(InnerTextMessage {
                msgtype: DingTalkMessageType::Text,
                text: InnerTextMessageText {
                    content: dingtalk_message.text_content.into(),
                }
            }),
            DingTalkMessageType::Link => serde_json::to_value(InnerLinkMessage {
                msgtype: DingTalkMessageType::Link,
                link: InnerLinkMessageLink {
                    title: dingtalk_message.link_title.into(),
                    text: dingtalk_message.link_text.into(),
                    pic_url: dingtalk_message.link_pic_url.into(),
                    message_url: dingtalk_message.link_message_url.into(),
                }
            }),
            DingTalkMessageType::Markdown => serde_json::to_value(InnerMarkdownMessage {
                msgtype: DingTalkMessageType::Markdown,
                markdown: InnerMarkdownMessageMarkdown {
                    title: dingtalk_message.markdown_title.into(),
                    text: dingtalk_message.markdown_content.into(),
                }
            }),
            DingTalkMessageType::ActionCard => serde_json::to_value(InnerActionCardMessage {
                msgtype: DingTalkMessageType::ActionCard,
                action_card: InnerActionCardMessageActionCard {
                    title: dingtalk_message.action_card_title.into(),
                    text: dingtalk_message.action_card_text.into(),
                    hide_avatar: dingtalk_message.action_card_hide_avatar,
                    btn_orientation: dingtalk_message.action_card_btn_orientation,
                }
            }),
            DingTalkMessageType::FeedCard => serde_json::to_value(InnerFeedCardMessage {
                msgtype: DingTalkMessageType::FeedCard,
                feed_card: InnerFeedCardMessageFeedCard {
                    links: {
                        let mut links: Vec<InnerFeedCardMessageFeedCardLink> = vec![];
                        for feed_card_link in &dingtalk_message.feed_card_links {
                            links.push(InnerFeedCardMessageFeedCardLink {
                                title: feed_card_link.title.clone(),
                                message_url: feed_card_link.message_url.clone(),
                                pic_url: feed_card_link.pic_url.clone(),
                            });
                        }
                        links
                    }
                }
            })
        }?;
        if DingTalkMessageType::ActionCard == dingtalk_message.message_type {
            if dingtalk_message.action_card_single_btn.is_some() {
                if let Some(single_btn) = dingtalk_message.action_card_single_btn.as_ref() {
                    message_json["actionCard"]["singleTitle"] = single_btn.title.as_str().into();
                    message_json["actionCard"]["singleURL"] = single_btn.action_url.as_str().into();
                };
            } else {
                let mut btns: Vec<InnerActionCardMessageBtn> = vec![];
                for action_card_btn in &dingtalk_message.action_card_btns {
                    btns.push(InnerActionCardMessageBtn {
                        title: action_card_btn.title.clone(),
                        action_url: action_card_btn.action_url.clone(),
                    });
                }
                message_json["actionCard"]["btns"] = serde_json::to_value(btns)?;
            }
        }
        if dingtalk_message.at_all || !dingtalk_message.at_mobiles.is_empty() {
            if let Some(m) = message_json.as_object_mut() {
                let mut at_mobiles: Vec<Value> = vec![];
                for m in &dingtalk_message.at_mobiles {
                    at_mobiles.push(Value::String(m.clone()));
                }
                let mut at_map = serde_json::Map::new();
                at_map.insert("atMobiles".into(), Value::Array(at_mobiles));
                at_map.insert("isAtAll".into(), Value::Bool(dingtalk_message.at_all));

                m.insert("at".into(), Value::Object(at_map));
            }
        }
        self.send(&serde_json::to_string(&message_json)?).await
    }

    /// Send text message
    pub async fn send_text(&self, text_message: &str) -> XResult<()> {
        self.send_message(&DingTalkMessage::new_text(text_message)).await
    }

    /// Send markdown message
    pub async fn send_markdown(&self, title: &str, text: &str) -> XResult<()> {
        self.send_message(&DingTalkMessage::new_markdown(title, text)).await
    }

    /// Send link message
    pub async fn send_link(&self, link_title: &'a str, link_text: &'a str, link_pic_url: &'a str, link_message_url: &'a str) -> XResult<()> {
        self.send_message(&DingTalkMessage::new_link(link_title, link_text, link_pic_url, link_message_url)).await
    }

    /// Direct send JSON message
    pub async fn send(&self, json_message: &str) -> XResult<()> {
        let client = reqwest::Client::new();
        let response = match client.post(&self.generate_signed_url()?)
              .header(CONTENT_TYPE, APPLICATION_JSON_UTF8)
              .body(json_message.as_bytes().to_vec())
              .send().await {
                  Ok(r) => r,
                  Err(e) => return Err(Box::new(Error::new(ErrorKind::Other, format!("Unknown error: {}", e))) as Box<dyn std::error::Error>),
              };

        match response.status().as_u16() {
            200_u16 => Ok(()),
            _ => Err(Box::new(Error::new(ErrorKind::Other, format!("Unknown status: {}", response.status().as_u16()))) as Box<dyn std::error::Error>),
        }
    }

    /// Generate signed dingtalk webhook URL
    pub fn generate_signed_url(&self) -> XResult<String> {
        if !self.direct_url.is_empty() {
            return Ok(self.direct_url.into());
        }
        let mut signed_url = String::with_capacity(1024);
        signed_url.push_str(self.default_webhook_url);

        if self.default_webhook_url.ends_with('?') {
            // Just Ok
        } else if self.default_webhook_url.contains('?') {
            if !self.default_webhook_url.ends_with('&') {
                signed_url.push('&');
            }
        } else {
            signed_url.push('?');
        }

        signed_url.push_str("access_token=");
        signed_url.push_str(&urlencoding::encode(self.access_token));

        if !self.sec_token.is_empty() {
            let timestamp = &format!("{}", SystemTime::now().duration_since(SystemTime::UNIX_EPOCH).unwrap().as_millis());
            let timestamp_and_secret = &format!("{}\n{}", timestamp, self.sec_token);
            let hmac_sha256 = base64::encode(&calc_hmac_sha256(self.sec_token.as_bytes(), timestamp_and_secret.as_bytes())?[..]);

            signed_url.push_str("&timestamp=");
            signed_url.push_str(timestamp);
            signed_url.push_str("&sign=");
            signed_url.push_str(&urlencoding::encode(&hmac_sha256));
        }

        Ok(signed_url)
    }

    // SAFE? may these codes cause memory leak?
    fn string_to_a_str(s: &str) -> &'a str {
        Box::leak(s.to_owned().into_boxed_str())
    }
}

/// calc hma_sha256 digest
fn calc_hmac_sha256(key: &[u8], message: &[u8]) -> XResult<Vec<u8>> {
    let mut mac = match Hmac::<Sha256>::new_varkey(key) {
        Ok(m) => m,
        Err(e) => return Err(Box::new(Error::new(ErrorKind::Other, format!("Hmac error: {}", e))))
    };
    mac.input(message);
    Ok(mac.result().code().to_vec())
}