// Copyright 2020 - developers of the `grammers` project.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// https://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or https://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
use crate::types::{Media, Uploaded};
use grammers_tl_types as tl;
use std::time::{SystemTime, UNIX_EPOCH};

// https://github.com/telegramdesktop/tdesktop/blob/e7fbcce9d9f0a8944eb2c34e74bd01b8776cb891/Telegram/SourceFiles/data/data_scheduled_messages.h#L52
const SCHEDULE_ONCE_ONLINE: i32 = 0x7FFFFFFE;

/// Construct and send rich text messages with various options.
#[derive(Default)]
pub struct InputMessage {
    pub(crate) background: bool,
    pub(crate) clear_draft: bool,
    pub(crate) entities: Vec<tl::enums::MessageEntity>,
    pub(crate) link_preview: bool,
    pub(crate) reply_markup: Option<tl::enums::ReplyMarkup>,
    pub(crate) reply_to: Option<i32>,
    pub(crate) schedule_date: Option<i32>,
    pub(crate) silent: bool,
    pub(crate) text: String,
    pub(crate) media: Option<tl::enums::InputMedia>,
    media_ttl: Option<i32>,
    mime_type: Option<String>,
}

impl InputMessage {
    /// Whether to "send this message as a background message".
    ///
    /// This description is taken from https://core.telegram.org/method/messages.sendMessage.
    pub fn background(mut self, background: bool) -> Self {
        self.background = background;
        self
    }

    /// Whether the draft in this chat, if any, should be cleared.
    pub fn clear_draft(mut self, clear_draft: bool) -> Self {
        self.clear_draft = clear_draft;
        self
    }

    /// The formatting entities within the message (such as bold, italics, etc.).
    pub fn fmt_entities(mut self, entities: Vec<tl::enums::MessageEntity>) -> Self {
        self.entities = entities;
        self
    }

    /// Whether the link preview be shown for the message.
    ///
    /// This has no effect when sending media, which cannot contain a link preview.
    pub fn link_preview(mut self, link_preview: bool) -> Self {
        self.link_preview = link_preview;
        self
    }

    /// The reply markup to show under the message.
    ///
    /// User accounts cannot use markup, and it will be ignored if set.
    pub fn reply_markup(mut self, reply_markup: Option<tl::enums::ReplyMarkup>) -> Self {
        self.reply_markup = reply_markup;
        self
    }

    /// The message identifier to which this message should reply to, if any.
    ///
    /// Otherwise, this message will not be a reply to any other.
    pub fn reply_to(mut self, reply_to: Option<i32>) -> Self {
        self.reply_to = reply_to;
        self
    }

    /// If set to a distant enough future time, the message won't be sent immediately,
    /// and instead it will be scheduled to be automatically sent at a later time.
    ///
    /// This scheduling is done server-side, and may not be accurate to the second.
    ///
    /// Bot accounts cannot schedule messages.
    pub fn schedule_date(mut self, schedule_date: Option<SystemTime>) -> Self {
        self.schedule_date = schedule_date.map(|t| {
            t.duration_since(UNIX_EPOCH)
                .map(|d| d.as_secs() as i32)
                .unwrap_or(0)
        });
        self
    }

    /// Schedule the message to be sent once the person comes online.
    ///
    /// This only works in private chats, and only if the person has their
    /// last seen visible.
    ///
    /// Bot accounts cannot schedule messages.
    pub fn schedule_once_online(mut self) -> Self {
        self.schedule_date = Some(SCHEDULE_ONCE_ONLINE);
        self
    }

    /// Whether the message should notify people or not.
    ///
    /// Defaults to `false`, which means it will notify them. Set it to `true`
    /// to alter this behaviour.
    pub fn silent(mut self, silent: bool) -> Self {
        self.silent = silent;
        self
    }

    /// Include the uploaded file as a photo in the message.
    ///
    /// The server will compress the image and convert it to JPEG format if necessary.
    ///
    /// The text will be the caption of the photo, which may be empty for no caption.
    pub fn photo(mut self, file: Uploaded) -> Self {
        self.media = Some(
            tl::types::InputMediaUploadedPhoto {
                file: file.input_file,
                stickers: None,
                ttl_seconds: self.media_ttl,
            }
            .into(),
        );
        self
    }

    /// Include the uploaded file as a document in the message.
    ///
    /// You can use this to send videos, stickers, audios, or uncompressed photos.
    ///
    /// The text will be the caption of the document, which may be empty for no caption.
    pub fn document(mut self, file: Uploaded) -> Self {
        let mime_type = self.get_file_mime(&file);
        let file_name = file.name().to_string();
        self.media = Some(
            tl::types::InputMediaUploadedDocument {
                nosound_video: false,
                force_file: false,
                file: file.input_file,
                thumb: None,
                mime_type,
                // TODO provide a way to set other attributes
                attributes: vec![tl::types::DocumentAttributeFilename { file_name }.into()],
                stickers: None,
                ttl_seconds: self.media_ttl,
            }
            .into(),
        );
        self
    }

    /// Copy media from an existing message.
    ///
    /// You can use this to send media from another message without re-uploading it.
    pub fn copy_media(mut self, media: &Media) -> Self {
        self.media = Some(media.to_input_media());
        self
    }

    /// Include the uploaded file as a document file in the message.
    ///
    /// You can use this to send any type of media as a simple document file.
    ///
    /// The text will be the caption of the file, which may be empty for no caption.
    pub fn file(mut self, file: Uploaded) -> Self {
        let mime_type = self.get_file_mime(&file);
        let file_name = file.name().to_string();
        self.media = Some(
            tl::types::InputMediaUploadedDocument {
                nosound_video: false,
                force_file: true,
                file: file.input_file,
                thumb: None,
                mime_type,
                // TODO provide a way to set other attributes
                attributes: vec![tl::types::DocumentAttributeFilename { file_name }.into()],
                stickers: None,
                ttl_seconds: self.media_ttl,
            }
            .into(),
        );
        self
    }

    /// Change the media's Time To Live (TTL).
    ///
    /// For example, this enables you to send a `photo` that can only be viewed for a certain
    /// amount of seconds before it expires.
    ///
    /// Not all media supports this feature.
    ///
    /// This method should be called before setting any media, else it won't have any effect.
    pub fn media_ttl(mut self, seconds: i32) -> Self {
        self.media_ttl = if seconds < 0 { None } else { Some(seconds) };
        self
    }

    /// Change the media's mime type.
    ///
    /// This method will override the mime type that would otherwise be automatically inferred
    /// from the extension of the used file
    ///
    /// If no mime type is set and it cannot be inferred, the mime type will be
    /// "application/octet-stream".
    ///
    /// This method should be called before setting any media, else it won't have any effect.
    pub fn mime_type(mut self, mime_type: &str) -> Self {
        self.mime_type = Some(mime_type.to_string());
        self
    }

    /// Return the mime type string for the given file.
    fn get_file_mime(&self, file: &Uploaded) -> String {
        if let Some(mime) = self.mime_type.as_ref() {
            mime.clone()
        } else if let Some(mime) = mime_guess::from_path(file.name()).first() {
            mime.essence_str().to_string()
        } else {
            "application/octet-stream".to_string()
        }
    }

    /// Builds a new message using the given plaintext as the message contents.
    pub fn text<T: AsRef<str>>(s: T) -> Self {
        Self {
            text: s.as_ref().to_string(),
            ..Self::default()
        }
    }

    /// Builds a new message from the given markdown-formatted string as the
    /// message contents and entities.
    ///
    /// Note that Telegram only supports a very limited subset of entities:
    /// bold, italic, underline, strikethrough, code blocks, pre blocks and inline links.
    #[cfg(feature = "markdown")]
    pub fn markdown<T: AsRef<str>>(s: T) -> Self {
        let (text, entities) = crate::parsers::parse_markdown_message(s.as_ref());
        Self {
            text,
            entities,
            ..Self::default()
        }
    }

    /// Builds a new message from the given HTML-formatted string as the
    /// message contents and entities.
    ///
    /// Note that Telegram only supports a very limited subset of entities:
    /// bold, italic, underline, strikethrough, code blocks, pre blocks and inline links.
    #[cfg(feature = "html")]
    pub fn html<T: AsRef<str>>(s: T) -> Self {
        let (text, entities) = crate::parsers::parse_html_message(s.as_ref());
        Self {
            text,
            entities,
            ..Self::default()
        }
    }
}

impl From<&str> for InputMessage {
    fn from(text: &str) -> Self {
        Self::text(text)
    }
}

impl From<String> for InputMessage {
    fn from(text: String) -> Self {
        Self {
            text,
            ..Self::default()
        }
    }
}