//
// imag - the personal information management suite for the commandline
// Copyright (C) 2015-2020 Matthias Beyer <mail@beyermatthias.de> and contributors
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; version
// 2.1 of the License.
//
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
// Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
//

use handlebars::{HelperDef, JsonRender, RenderError, RenderContext, Helper, Output, Context};
use handlebars::Handlebars as Registry;
use serde_json::value::Value;
use ansi_term::Colour;
use ansi_term::Style;

/// Helper type for passing data to handlebars
///
/// This helper type can be used to fill a BtreeMap<String, HandlebarsData> which is then passed to
/// Handlebars::render() for passing data to the template string.
///
#[derive(Clone, Debug, Serialize)]
#[serde(untagged)]
pub enum HandlebarsData {
    Bool(bool),
    Int(usize),
    Float(f64),
    Str(String),
}

impl From<bool> for HandlebarsData {
    fn from(b: bool) -> Self {
        HandlebarsData::Bool(b)
    }
}

impl From<usize> for HandlebarsData {
    fn from(u: usize) -> Self {
        HandlebarsData::Int(u)
    }
}

impl From<f64> for HandlebarsData {
    fn from(f: f64) -> Self {
        HandlebarsData::Float(f)
    }
}

impl From<String> for HandlebarsData {
    fn from(s: String) -> Self {
        HandlebarsData::Str(s)
    }
}


#[derive(Clone, Copy)]
pub struct ColorizeBlackHelper;

impl HelperDef for ColorizeBlackHelper {
    fn call<'reg: 'rc, 'rc>(&self, h: &Helper<'reg, 'rc>, _r: &'reg Registry, _ctx: &'rc Context, _rc: &mut RenderContext<'reg, 'rc>, out: &mut dyn Output) -> Result<(), RenderError> {
        colorize(Colour::Black, h, out)
    }
}

#[derive(Clone, Copy)]
pub struct ColorizeBlueHelper;

impl HelperDef for ColorizeBlueHelper {
    fn call<'reg: 'rc, 'rc>(&self, h: &Helper<'reg, 'rc>, _r: &'reg Registry, _ctx: &'rc Context, _rc: &mut RenderContext<'reg, 'rc>, out: &mut dyn Output) -> Result<(), RenderError> {
        colorize(Colour::Blue, h, out)
    }
}

#[derive(Clone, Copy)]
pub struct ColorizeCyanHelper;

impl HelperDef for ColorizeCyanHelper {
    fn call<'reg: 'rc, 'rc>(&self, h: &Helper<'reg, 'rc>, _r: &'reg Registry, _ctx: &'rc Context, _rc: &mut RenderContext<'reg, 'rc>, out: &mut dyn Output) -> Result<(), RenderError> {
        colorize(Colour::Cyan, h, out)
    }
}

#[derive(Clone, Copy)]
pub struct ColorizeGreenHelper;

impl HelperDef for ColorizeGreenHelper {
    fn call<'reg: 'rc, 'rc>(&self, h: &Helper<'reg, 'rc>, _r: &'reg Registry, _ctx: &'rc Context, _rc: &mut RenderContext<'reg, 'rc>, out: &mut dyn Output) -> Result<(), RenderError> {
        colorize(Colour::Green, h, out)
    }
}

#[derive(Clone, Copy)]
pub struct ColorizePurpleHelper;

impl HelperDef for ColorizePurpleHelper {
    fn call<'reg: 'rc, 'rc>(&self, h: &Helper<'reg, 'rc>, _r: &'reg Registry, _ctx: &'rc Context, _rc: &mut RenderContext<'reg, 'rc>, out: &mut dyn Output) -> Result<(), RenderError> {
        colorize(Colour::Purple, h, out)
    }
}

#[derive(Clone, Copy)]
pub struct ColorizeRedHelper;

impl HelperDef for ColorizeRedHelper {
    fn call<'reg: 'rc, 'rc>(&self, h: &Helper<'reg, 'rc>, _r: &'reg Registry, _ctx: &'rc Context, _rc: &mut RenderContext<'reg, 'rc>, out: &mut dyn Output) -> Result<(), RenderError> {
        colorize(Colour::Red, h, out)
    }
}

#[derive(Clone, Copy)]
pub struct ColorizeWhiteHelper;

impl HelperDef for ColorizeWhiteHelper {
    fn call<'reg: 'rc, 'rc>(&self, h: &Helper<'reg, 'rc>, _r: &'reg Registry, _ctx: &'rc Context, _rc: &mut RenderContext<'reg, 'rc>, out: &mut dyn Output) -> Result<(), RenderError> {
        colorize(Colour::White, h, out)
    }
}

#[derive(Clone, Copy)]
pub struct ColorizeYellowHelper;

impl HelperDef for ColorizeYellowHelper {
    fn call<'reg: 'rc, 'rc>(&self, h: &Helper<'reg, 'rc>, _r: &'reg Registry, _ctx: &'rc Context, _rc: &mut RenderContext<'reg, 'rc>, out: &mut dyn Output) -> Result<(), RenderError> {
        colorize(Colour::Yellow, h, out)
    }
}

#[inline]
fn colorize(color: Colour, h: &Helper, output: &mut dyn Output) -> Result<(), RenderError> {
    let p = h.param(0).ok_or_else(|| RenderError::new("Too few arguments"))?;

    output.write(&format!("{}", color.paint(p.value().render())))?;
    Ok(())
}

#[derive(Clone, Copy)]
pub struct UnderlineHelper;

impl HelperDef for UnderlineHelper {
    fn call<'reg: 'rc, 'rc>(&self, h: &Helper<'reg, 'rc>, _r: &'reg Registry, _ctx: &'rc Context, _rc: &mut RenderContext<'reg, 'rc>, out: &mut dyn Output) -> Result<(), RenderError> {
            let p = h.param(0).ok_or_else(|| RenderError::new("Too few arguments"))?;
            let s = Style::new().underline();
            out.write(&format!("{}", s.paint(p.value().render())))?;
            Ok(())
        }
}

#[derive(Clone, Copy)]
pub struct BoldHelper;

impl HelperDef for BoldHelper {
    fn call<'reg: 'rc, 'rc>(&self, h: &Helper<'reg, 'rc>, _r: &'reg Registry, _ctx: &'rc Context, _rc: &mut RenderContext<'reg, 'rc>, out: &mut dyn Output) -> Result<(), RenderError> {
            let p = h.param(0).ok_or_else(|| RenderError::new("Too few arguments"))?;
            let s = Style::new().bold();
            out.write(&format!("{}", s.paint(p.value().render())))?;
            Ok(())
        }
}

#[derive(Clone, Copy)]
pub struct BlinkHelper;

impl HelperDef for BlinkHelper {
    fn call<'reg: 'rc, 'rc>(&self, h: &Helper<'reg, 'rc>, _r: &'reg Registry, _ctx: &'rc Context, _rc: &mut RenderContext<'reg, 'rc>, out: &mut dyn Output) -> Result<(), RenderError> {
            let p = h.param(0).ok_or_else(|| RenderError::new("Too few arguments"))?;
            let s = Style::new().blink();
            out.write(&format!("{}", s.paint(p.value().render())))?;
            Ok(())
        }
}

#[derive(Clone, Copy)]
pub struct StrikethroughHelper;

impl HelperDef for StrikethroughHelper {
    fn call<'reg: 'rc, 'rc>(&self, h: &Helper<'reg, 'rc>, _r: &'reg Registry, _ctx: &'rc Context, _rc: &mut RenderContext<'reg, 'rc>, out: &mut dyn Output) -> Result<(), RenderError> {
            let p = h.param(0).ok_or_else(|| RenderError::new("Too few arguments"))?;
            let s = Style::new().strikethrough();
            out.write(&format!("{}", s.paint(p.value().render())))?;
            Ok(())
        }
}

fn param_to_number(idx: usize, h: &Helper) -> Result<u64, RenderError> {
    fn typenameof(v: &Value) -> String {
        match *v {
            Value::Null      => "Null",
            Value::Bool(_)   => "Bool",
            Value::Number(_) => "Number",
            Value::String(_) => "String",
            Value::Array(_)  => "Array",
            Value::Object(_) => "Object",
        }.to_owned()
    }

    match h.param(idx).ok_or_else(|| RenderError::new("Too few arguments"))?.value() {
        Value::Number(ref num) => num.as_u64().ok_or_else(|| RenderError::new("Number cannot be parsed")),
        other => {
            let msg = format!("Type error: First argument should be a number, but is {} -> {:?}", typenameof(other), serde_json::to_string(other));
            Err(RenderError::new(msg))
        },
    }
}

#[derive(Clone, Copy)]
pub struct LeftPadHelper;

impl HelperDef for LeftPadHelper {
    fn call<'reg: 'rc, 'rc>(&self, h: &Helper<'reg, 'rc>, _r: &'reg Registry, _ctx: &'rc Context, _rc: &mut RenderContext<'reg, 'rc>, out: &mut dyn Output) -> Result<(), RenderError> {
        let count = param_to_number(0, h)? as usize;
        let text = h.param(1).ok_or_else(|| RenderError::new("Too few arguments"))?;
        let text = format!("{:>width$}", text.value().render(), width = count);
        out.write(&text)?;
        Ok(())
    }
}

#[derive(Clone, Copy)]
pub struct RightPadHelper;

impl HelperDef for RightPadHelper {
    fn call<'reg: 'rc, 'rc>(&self, h: &Helper<'reg, 'rc>, _r: &'reg Registry, _ctx: &'rc Context, _rc: &mut RenderContext<'reg, 'rc>, out: &mut dyn Output) -> Result<(), RenderError> {
        let count = param_to_number(0, h)? as usize;
        let text = h.param(1).ok_or_else(|| RenderError::new("Too few arguments"))?;
        let text = format!("{:width$}", text.value().render(), width = count);
        out.write(&text)?;
        Ok(())
    }
}

#[derive(Clone, Copy)]
pub struct AbbrevHelper;

impl HelperDef for AbbrevHelper {
    fn call<'reg: 'rc, 'rc>(&self, h: &Helper<'reg, 'rc>, _r: &'reg Registry, _ctx: &'rc Context, _rc: &mut RenderContext<'reg, 'rc>, out: &mut dyn Output) -> Result<(), RenderError> {
        let count = param_to_number(0, h)? as usize;
        let text = h.param(1).ok_or_else(|| RenderError::new("Too few arguments"))?.value().render();
        out.write(&text.chars().take(count).collect::<String>())?;
        Ok(())
    }
}


#[derive(Clone, Copy)]
pub struct IndentionHelper;

impl HelperDef for IndentionHelper {
    fn call<'reg: 'rc, 'rc>(&self, h: &Helper<'reg, 'rc>, _r: &'reg Registry, _ctx: &'rc Context, _rc: &mut RenderContext<'reg, 'rc>, out: &mut dyn Output) -> Result<(), RenderError> {
        let count = param_to_number(0, h)? as usize;
        let text = h.param(1).ok_or_else(|| RenderError::new("Too few arguments"))?.value().render();
        out.write(&::std::iter::repeat(text).take(count).collect::<String>())?;
        Ok(())
    }
}

pub fn register_all_color_helpers(handlebars: &mut Registry) {
    handlebars.register_helper("black"  , Box::new(ColorizeBlackHelper));
    handlebars.register_helper("blue"   , Box::new(ColorizeBlueHelper));
    handlebars.register_helper("cyan"   , Box::new(ColorizeCyanHelper));
    handlebars.register_helper("green"  , Box::new(ColorizeGreenHelper));
    handlebars.register_helper("purple" , Box::new(ColorizePurpleHelper));
    handlebars.register_helper("red"    , Box::new(ColorizeRedHelper));
    handlebars.register_helper("white"  , Box::new(ColorizeWhiteHelper));
    handlebars.register_helper("yellow" , Box::new(ColorizeYellowHelper));
}

pub fn register_all_format_helpers(handlebars: &mut Registry) {
    handlebars.register_helper("underline"     , Box::new(UnderlineHelper));
    handlebars.register_helper("bold"          , Box::new(BoldHelper));
    handlebars.register_helper("blink"         , Box::new(BlinkHelper));
    handlebars.register_helper("strikethrough" , Box::new(StrikethroughHelper));
    handlebars.register_helper("lpad"          , Box::new(LeftPadHelper));
    handlebars.register_helper("rpad"          , Box::new(RightPadHelper));
    handlebars.register_helper("abbrev"        , Box::new(AbbrevHelper));
    handlebars.register_helper("indent"        , Box::new(IndentionHelper));
}