//  Stiletto
//  Copyright (C) 2020 Stiletto Authors
//
//  This program is free software: you can redistribute it and/or modify
//  it under the terms of the GNU Affero General Public License as published by
//  the Free Software Foundation, either version 3 of the License, or
//  (at your option) any later version.
//
//  This program 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 Affero General Public License for more details.
//
//  You should have received a copy of the GNU Affero General Public License
//  along with this program.  If not, see <https://www.gnu.org/licenses/>.

use log::{info, warn};

use druid::commands;
use druid::im::vector;
use druid::widget::prelude::*;
use druid::widget::{Align, Button, CrossAxisAlignment, Flex, List, SizedBox, WidgetExt};
use druid::{
    AppDelegate, AppLauncher, Color, Command, Data, DelegateCtx, Env, FileDialogOptions, FileSpec,
    Handled, Lens, LocalizedString, Target, WindowDesc,
};

use im::Vector;

use stiletto::canvas::Canvas;
use stiletto::history::VersionedCanvas;
use stiletto::tool::{CanvasToolCtx, CanvasToolParams};
use stiletto::widget::{build_simple_tool_widget, CanvasState, CanvasToolIconState, CanvasWidget};
use stiletto::DocumentSnapshot;

pub fn main() {
    let window = WindowDesc::new(build_ui)
        .window_size((1024.0, 1400.0))
        .title(
            LocalizedString::new("custom-widget-demo-window-title").with_placeholder("Stiletto"),
        );

    let default_pen_params = CanvasToolParams::Pen {
        thickness: 2.0,
        color: Color::rgb(0.0, 0.0, 0.0),
    };
    let default_pen_params_2 = CanvasToolParams::Pen {
        thickness: 2.0,
        color: Color::rgb(255.0, 0.0, 0.0),
    };
    let canvas_data = StilettoState {
        canvas: CanvasState {
            versioned_canvas: VersionedCanvas::new(Canvas {
                elements: vector![],
            }),
            tool_ctx: CanvasToolCtx::new(default_pen_params.clone()),
        },
        tool_icons: vector![
            CanvasToolIconState {
                tool_params: default_pen_params,
                selected: true,
            },
            CanvasToolIconState {
                tool_params: default_pen_params_2,
                selected: false,
            },
            CanvasToolIconState {
                tool_params: CanvasToolParams::Eraser,
                selected: false,
            },
        ],
        current_tool: 0,
    };
    AppLauncher::with_window(window)
        .use_simple_logger()
        .delegate(Delegate)
        .launch(canvas_data)
        .expect("launch failed");
}

#[derive(Clone, Data, Lens)]
struct StilettoState {
    canvas: CanvasState,
    tool_icons: Vector<CanvasToolIconState>,
    current_tool: usize,
}

fn build_ui() -> impl Widget<StilettoState> {
    let history_buttons = Flex::row()
        .cross_axis_alignment(CrossAxisAlignment::Center)
        .with_child(Button::new("Undo").on_click(
            |_ctx: &mut EventCtx, data: &mut StilettoState, _env: &Env| data.canvas.perform_undo(),
        ))
        .with_child(Button::new("Redo").on_click(
            |_ctx: &mut EventCtx, data: &mut StilettoState, _env: &Env| data.canvas.perform_redo(),
        ));

    let stlt = FileSpec::new("Stiletto notebook", &["stlt"]);
    let save_dialog_options = FileDialogOptions::new()
        .allowed_types(vec![stlt])
        .default_type(stlt);
    let open_dialog_options = save_dialog_options.clone();

    let save_buttons = Flex::row()
        .cross_axis_alignment(CrossAxisAlignment::Center)
        .with_child(Button::new("Open").on_click(move |ctx, _, _| {
            ctx.submit_command(Command::new(
                druid::commands::SHOW_OPEN_PANEL,
                open_dialog_options.clone(),
                Target::Auto,
            ))
        }))
        .with_child(Button::new("Save").on_click(move |ctx, _, _| {
            ctx.submit_command(Command::new(
                druid::commands::SHOW_SAVE_PANEL,
                save_dialog_options.clone(),
                Target::Auto,
            ))
        }));

    let tool_buttons = Flex::row()
        .cross_axis_alignment(CrossAxisAlignment::Center)
        .with_flex_child(
            List::new(|| {
                build_simple_tool_widget(30.0, 30.0, 5.0)
                    .padding((8.0, 0.0))
                    .on_click(|ctx, tool_state, _| {
                        tool_state.selected = true;
                        ctx.submit_command(stiletto::commands::UPDATE_TOOL);
                    })
            })
            .horizontal()
            .lens(StilettoState::tool_icons),
            1.0,
        );

    let toolbar = Flex::row()
        .cross_axis_alignment(CrossAxisAlignment::Center)
        .with_spacer(30.0)
        .with_flex_child(Align::left(history_buttons), 1.0)
        .with_spacer(10.0)
        .with_flex_child(Align::left(tool_buttons), 2.0)
        .with_spacer(20.0)
        .with_flex_child(Align::right(save_buttons), 1.0)
        .with_spacer(30.0);

    Flex::column()
        .cross_axis_alignment(CrossAxisAlignment::Center)
        .must_fill_main_axis(true)
        .with_child(SizedBox::new(Align::left(toolbar)).height(50.0))
        .with_flex_child((CanvasWidget {}).lens(StilettoState::canvas), 1.0)
}

struct Delegate;

impl AppDelegate<StilettoState> for Delegate {
    fn command(
        &mut self,
        _ctx: &mut DelegateCtx,
        _target: Target,
        cmd: &Command,
        data: &mut StilettoState,
        _env: &Env,
    ) -> Handled {
        use std::fs::File;

        if let Some(file_info) = cmd.get(commands::SAVE_FILE_AS) {
            let res_file = File::create(file_info.path());
            if let Ok(f) = res_file {
                let write_res =
                    serde_json::to_writer_pretty(f, &data.canvas.get_document_snapshot());
                if write_res.is_err() {
                    warn!("Error while saving: {:?}", write_res.err());
                } else {
                    info!("Written to file: {}", file_info.path().display());
                }
            } else {
                warn!("Cannot create file: {:?}", res_file.err());
            }
            return Handled::Yes;
        }
        if let Some(file_info) = cmd.get(commands::OPEN_FILE) {
            if let Ok(f) = File::open(file_info.path()) {
                let res_snapshot: Result<DocumentSnapshot, serde_json::Error> =
                    serde_json::from_reader(f);
                if let Ok(document_snapshot) = res_snapshot {
                    data.canvas.set_from_snapshot(document_snapshot);
                    info!("Loaded file {}", file_info.path().display());
                } else {
                    warn!("didn't work: {:?}", res_snapshot.err());
                }
            }
            return Handled::Yes;
        }
        if cmd.get(stiletto::commands::UPDATE_TOOL).is_some() {
            let old_tool = data.current_tool;
            if let Some(new_tool) = data
                .tool_icons
                .iter()
                .enumerate()
                .position(|(pos, x)| pos != old_tool && x.selected)
            {
                info!("Changing active tool to: tool #{}", new_tool);
                data.tool_icons.get_mut(old_tool).unwrap().selected = false;
                data.current_tool = new_tool;
                data.canvas.set_tool_ctx(CanvasToolCtx::new(
                    data.tool_icons.get(new_tool).unwrap().tool_params.clone(),
                ));
            }
        }
        Handled::No
    }
}