use anyhow::Result;
use std::io;

use lazy_static::lazy_static;

extern crate enum_map;
use enum_map::enum_map;
use enum_map::{Enum, EnumMap};

pub mod program;
pub mod digest;

use crate::meta_plugin::program::MetaPluginProgram;
use crate::meta_plugin::digest::DigestSha256MetaPlugin;

use strum::IntoEnumIterator;

#[derive(Debug, Eq, PartialEq, Clone, strum::EnumIter, strum::Display, strum::EnumString, Enum)]
#[strum(ascii_case_insensitive)]
pub enum MetaPluginType {
    FileMagic,
    DigestSha256,
    DigestMd5,
    ReadTime,
    ReadRate,
}

pub trait MetaPlugin {
    fn is_supported(&self) -> bool {
        true
    }
    fn create(&self) -> Result<Box<dyn Write>>;
    fn finalize(&mut self) -> io::Result<String>;

    // Update the meta plugin with new data
    fn update(&mut self, data: &[u8]);

    fn meta_name(&mut self) -> String;
}

use std::io::Write;

lazy_static! {
    pub static ref META_PLUGIN_PROGRAMS: EnumMap<MetaPluginType, Option<MetaPluginProgram>> = enum_map! {
        MetaPluginType::FileMagic => {
            let program = MetaPluginProgram::new("file", vec!["-bE", "-"], "file_magic".to_string(), true);
            if program.supported { Some(program) } else { None }
        }
        MetaPluginType::DigestSha256 => {
            let program = MetaPluginProgram::new("sha256sum", vec![], "digest_sha256".to_string(), true);
            if program.supported { Some(program) } else { None }
        }
        MetaPluginType::DigestMd5 => {
            let program = MetaPluginProgram::new("md5sum", vec![], "digest_md5".to_string(), true);
            if program.supported { Some(program) } else { None }
        }
    };
}

pub fn get_meta_plugin(meta_plugin_type: MetaPluginType) -> Box<dyn MetaPlugin> {
    match meta_plugin_type {
        MetaPluginType::FileMagic => Box::new(MetaPluginProgram::new("file", vec!["-bE", "-"], "file_magic".to_string(), true)),
        MetaPluginType::DigestSha256 => Box::new(DigestSha256MetaPlugin::new()),
        MetaPluginType::DigestMd5 => Box::new(MetaPluginProgram::new("md5sum", vec![], "digest_md5".to_string(), true)),
        MetaPluginType::ReadTime => Box::new(ReadTimeMetaPlugin::new()),
        MetaPluginType::ReadRate => Box::new(ReadRateMetaPlugin::new()),
    }
}

pub fn default_meta_plugin_type() -> MetaPluginType {
    let mut default = MetaPluginType::FileMagic;
    for meta_plugin_type in MetaPluginType::iter() {
        let meta_plugin = get_meta_plugin(meta_plugin_type.clone());
        if meta_plugin.is_supported() {
            default = meta_plugin_type;
            break;
        }
    }
    default
}