// Copyright 2023 The Grim Developers
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

use egui::{Align, Align2, Layout, Margin, RichText, Rounding, ScrollArea, TextStyle, Widget};
use egui_extras::{Size, StripBuilder};
use grin_core::global::ChainTypes;

use crate::AppConfig;
use crate::gui::Colors;
use crate::gui::icons::{ARROW_LEFT, CARET_RIGHT, COMPUTER_TOWER, EYE, EYE_SLASH, FOLDER_LOCK, FOLDER_OPEN, GEAR, GLOBE, GLOBE_SIMPLE, LOCK_KEY, PLUS, SIDEBAR_SIMPLE, SPINNER, SUITCASE, WARNING_CIRCLE};
use crate::gui::platform::PlatformCallbacks;
use crate::gui::views::{Modal, Root, TitlePanel, View};
use crate::gui::views::types::{ModalContainer, ModalPosition, TitleType};
use crate::gui::views::wallets::creation::WalletCreation;
use crate::gui::views::wallets::WalletContent;
use crate::wallet::{ConnectionsConfig, ExternalConnection, Wallet, Wallets};

/// Wallets content.
pub struct WalletsContent {
    /// Chain type for loaded wallets.
    chain_type: ChainTypes,
    /// Loaded list of wallets.
    wallets: Wallets,

    /// Password to open wallet for [`Modal`].
    pass_edit: String,
    /// Flag to show/hide password at [`egui::TextEdit`] field.
    hide_pass: bool,
    /// Flag to check if wrong password was entered.
    wrong_pass: bool,

    /// Selected [`Wallet`] content.
    wallet_content: WalletContent,
    /// Wallet creation content.
    creation_content: WalletCreation,

    /// Flag to show [`Wallet`] list at dual panel mode.
    show_wallets_at_dual_panel: bool,

    /// [`Modal`] identifiers allowed at this ui container.
    modal_ids: Vec<&'static str>
}

/// Identifier for wallet opening [`Modal`].
const OPEN_WALLET_MODAL: &'static str = "open_wallet_modal";

impl Default for WalletsContent {
    fn default() -> Self {
        Self {
            chain_type: AppConfig::chain_type(),
            wallets: Wallets::default(),
            pass_edit: "".to_string(),
            hide_pass: true,
            wrong_pass: false,
            wallet_content: WalletContent::default(),
            creation_content: WalletCreation::default(),
            show_wallets_at_dual_panel: AppConfig::show_wallets_at_dual_panel(),
            modal_ids: vec![
                OPEN_WALLET_MODAL,
                WalletCreation::NAME_PASS_MODAL
            ]
        }
    }
}

impl ModalContainer for WalletsContent {
    fn modal_ids(&self) -> &Vec<&'static str> {
        &self.modal_ids
    }

    fn modal_ui(&mut self,
                ui: &mut egui::Ui,
                _: &mut eframe::Frame,
                modal: &Modal,
                cb: &dyn PlatformCallbacks) {
        match modal.id {
            OPEN_WALLET_MODAL => self.open_wallet_modal_ui(ui, modal, cb),
            WalletCreation::NAME_PASS_MODAL => {
                self.creation_content.name_pass_modal_ui(ui, modal, cb)
            },
            _ => {}
        }
    }
}

impl WalletsContent {
    pub fn ui(&mut self, ui: &mut egui::Ui, frame: &mut eframe::Frame, cb: &dyn PlatformCallbacks) {
        // Draw modal content for current ui container.
        self.current_modal_ui(ui, frame, cb);

        // Setup list of wallets if chain type was changed.
        let chain_type = AppConfig::chain_type();
        if self.chain_type != chain_type {
            self.wallets.reinit(chain_type);
            self.chain_type = chain_type;
        }
        let empty_list = self.wallets.list.is_empty();

        // Setup wallet content flags.
        let create_wallet = self.creation_content.can_go_back();
        let show_wallet = self.wallets.is_selected_open();

        // Setup panels parameters.
        let dual_panel = is_dual_panel_mode(ui, frame);
        let open_wallet_panel = dual_panel || show_wallet || create_wallet || empty_list;
        let wallet_panel_width = self.wallet_panel_width(ui, empty_list, dual_panel, show_wallet);
        let content_width = ui.available_width();

        // Show title panel.
        self.title_ui(ui, frame, dual_panel, create_wallet, show_wallet);

        // Show wallet panel content.
        egui::SidePanel::right("wallet_panel")
            .resizable(false)
            .min_width(wallet_panel_width)
            .frame(egui::Frame {
                fill: if empty_list && !create_wallet
                    || (dual_panel && show_wallet && !self.show_wallets_at_dual_panel) {
                    Colors::FILL_DARK
                } else {
                    if create_wallet {
                        Colors::WHITE
                    } else {
                        Colors::BUTTON
                    }
                },
                ..Default::default()
            })
            .show_animated_inside(ui, open_wallet_panel, |ui| {
                // Do not draw content on zero width.
                if content_width == 0.0 {
                    return;
                }
                if create_wallet || !show_wallet {
                    // Show wallet creation content.
                    self.creation_content.ui(ui, frame, cb, |wallet| {
                        // Add created wallet to list.
                        self.wallets.add(wallet);
                    });
                } else  {
                    for mut wallet in self.wallets.list.clone() {
                        // Show content for selected wallet.
                        if self.wallets.is_selected(wallet.config.id) {
                            // Setup wallet content width.
                            let mut rect = ui.available_rect_before_wrap();
                            let mut width = ui.available_width();
                            if dual_panel && self.show_wallets_at_dual_panel {
                                width = content_width - Root::SIDE_PANEL_WIDTH;
                            }
                            rect.set_width(width);
                            // Show wallet content.
                            ui.allocate_ui_at_rect(rect, |ui| {
                                self.wallet_content.ui(ui, frame, &mut wallet, cb);
                            });
                            break;
                        }
                    }
                }
            });

        // Show non-empty list if wallet is not creating.
        if !empty_list && !create_wallet {
            // Flag to check if wallet list is hidden on the screen.
            let list_hidden = content_width == 0.0
                || (dual_panel && show_wallet && !self.show_wallets_at_dual_panel)
                || (!dual_panel && show_wallet);

            // Show wallet list panel.
            egui::CentralPanel::default()
                .frame(egui::Frame {
                    stroke: View::DEFAULT_STROKE,
                    fill: Colors::FILL_DARK,
                    inner_margin: Margin {
                        left: if list_hidden {
                            0.0
                        } else {
                            View::far_left_inset_margin(ui) + 4.0
                        },
                        right: if list_hidden {
                            0.0
                        } else {
                            View::far_right_inset_margin(ui, frame) + 4.0
                        },
                        top: 4.0,
                        bottom: View::get_bottom_inset() + 4.0,
                    },
                    ..Default::default()
                })
                .show_inside(ui, |ui| {
                    // Do not draw content when list is hidden.
                    if list_hidden {
                        return;
                    }

                    // Setup flag to show wallet creation button if wallet is not showing
                    // at non-dual panel mode or showing at dual panel mode.
                    let show_creation_btn
                        = (!show_wallet && !dual_panel) || (dual_panel && show_wallet);

                    // Show list of wallets.
                    let scroll = self.wallet_list_ui(ui, dual_panel, show_creation_btn, cb);

                    if show_creation_btn {
                        // Setup right margin for button.
                        let mut right_margin = if dual_panel { wallet_panel_width } else { 0.0 };
                        if scroll { right_margin += 6.0 }
                        // Show wallet creation button.
                        self.create_wallet_btn_ui(ui, right_margin, cb);
                    }
                });
        }
    }

    /// Draw [`TitlePanel`] content.
    fn title_ui(&mut self,
                ui: &mut egui::Ui,
                frame: &mut eframe::Frame,
                dual_panel: bool,
                create_wallet: bool,
                show_wallet: bool) {
        // Setup title text.
        let title_text = if create_wallet {
            t!("wallets.add")
        } else {
            t!("wallets.title")
        };
        let title_content = TitleType::Single(title_text.to_uppercase());

        // Draw title panel.
        TitlePanel::ui(title_content, |ui, frame| {
            if show_wallet && !dual_panel {
                View::title_button(ui, ARROW_LEFT, || {
                    self.wallets.select(None);
                });
            } else if create_wallet {
                View::title_button(ui, ARROW_LEFT, || {
                    self.creation_content.back();
                });
            } else if show_wallet && dual_panel {
                let show_list = self.show_wallets_at_dual_panel;
                let list_icon = if show_list {
                    SIDEBAR_SIMPLE
                } else {
                    SUITCASE
                };
                View::title_button(ui, list_icon, || {
                    self.show_wallets_at_dual_panel = !show_list;
                    AppConfig::toggle_show_wallets_at_dual_panel();
                });
            } else if !Root::is_dual_panel_mode(frame) {
                View::title_button(ui, GLOBE, || {
                    Root::toggle_network_panel();
                });
            };
        }, |ui, frame| {
            View::title_button(ui, GEAR, || {
                //TODO: show settings.
            });
        }, ui, frame);
    }

    /// Calculate [`WalletContent`] panel width.
    fn wallet_panel_width(
        &self,
        ui:&mut egui::Ui,
        list_empty: bool,
        dual_panel: bool,
        show_wallet: bool
    ) -> f32 {
        let create_wallet = self.creation_content.can_go_back();
        let available_width = if list_empty || create_wallet || (show_wallet && !dual_panel)
            || (show_wallet && !self.show_wallets_at_dual_panel) {
            ui.available_width()
        } else {
            ui.available_width() - Root::SIDE_PANEL_WIDTH
        };
        if dual_panel && show_wallet && self.show_wallets_at_dual_panel {
            let min_width = Root::SIDE_PANEL_WIDTH + View::get_right_inset();
            f32::max(min_width, available_width)
        } else {
            available_width
        }
    }

    /// Draw list of wallets. Returns `true` if scroller is showing.
    fn wallet_list_ui(&mut self,
                      ui: &mut egui::Ui,
                      dual_panel: bool,
                      show_creation_btn: bool,
                      cb: &dyn PlatformCallbacks) -> bool {
        let mut scroller_showing = false;
        ui.scope(|ui| {
            // Setup scroll bar color.
            ui.style_mut().visuals.widgets.inactive.bg_fill = Colors::ITEM_HOVER;
            ui.style_mut().visuals.widgets.hovered.bg_fill = Colors::STROKE;

            // Draw list of wallets.
            let scroll = ScrollArea::vertical()
                .id_source("wallet_list")
                .auto_shrink([false; 2])
                .show(ui, |ui| {
                    ui.vertical_centered(|ui| {
                        // Setup wallet list width.
                        let mut rect = ui.available_rect_before_wrap();
                        let mut width = ui.available_width();
                        if !dual_panel {
                            width = f32::min(width, Root::SIDE_PANEL_WIDTH * 1.3)
                        }
                        if width == 0.0 {
                            return;
                        }
                        rect.set_width(width);

                        ui.allocate_ui(rect.size(), |ui| {
                            for mut wallet in self.wallets.list.clone() {
                                // Draw wallet list item.
                                self.wallet_item_ui(ui, &mut wallet, cb);
                                ui.add_space(5.0);
                            }
                            // Add space for wallet creation button.
                            if show_creation_btn {
                                ui.add_space(52.0);
                            }
                        });
                    });
                });
            // Scroller is showing if content size is larger than content on the screen.
            scroller_showing = scroll.content_size.y > scroll.inner_rect.size().y;
        });
        scroller_showing
    }

    /// Draw wallet list item.
    fn wallet_item_ui(&mut self,
                      ui: &mut egui::Ui,
                      wallet: &mut Wallet,
                      cb: &dyn PlatformCallbacks) {
        let id = wallet.config.id;
        let is_selected = self.wallets.is_selected(id);
        let is_current = wallet.is_open() && is_selected;

        // Draw round background.
        let mut rect = ui.available_rect_before_wrap();
        rect.set_height(78.0);
        let rounding = View::item_rounding(0, 1, false);
        let bg_color = if is_current { Colors::ITEM_CURRENT } else { Colors::FILL };
        ui.painter().rect(rect, rounding, bg_color, View::HOVER_STROKE);

        ui.allocate_ui_with_layout(rect.size(), Layout::right_to_left(Align::Center), |ui| {
            // Setup padding for item buttons.
            ui.style_mut().spacing.button_padding = egui::vec2(14.0, 0.0);
            // Setup rounding for item buttons.
            ui.style_mut().visuals.widgets.inactive.rounding = Rounding::same(8.0);
            ui.style_mut().visuals.widgets.hovered.rounding = Rounding::same(8.0);
            ui.style_mut().visuals.widgets.active.rounding = Rounding::same(8.0);

            if !wallet.is_open() {
                // Show button to open closed wallet.
                View::item_button(ui, View::item_rounding(0, 1, true), FOLDER_OPEN, None, || {
                    self.wallets.select(Some(id));
                    self.show_open_wallet_modal(cb);
                });
            } else {
                if !is_selected {
                    // Show button to select opened wallet.
                    View::item_button(ui, View::item_rounding(0, 1, true), CARET_RIGHT, None, || {
                        self.wallets.select(Some(id));
                    });
                }
                // Show button to close opened wallet.
                View::item_button(ui, if !is_selected {
                    Rounding::none()
                } else {
                    View::item_rounding(0, 1, true)
                }, LOCK_KEY, None, || {
                    let _ = wallet.close();
                });
            }

            let layout_size = ui.available_size();
            ui.allocate_ui_with_layout(layout_size, Layout::left_to_right(Align::Center), |ui| {
                ui.add_space(7.0);
                ui.vertical(|ui| {
                    ui.add_space(3.0);
                    // Setup wallet name text.
                    let name_color = if is_selected { Colors::BLACK } else { Colors::TITLE };
                    View::ellipsize_text(ui, wallet.config.name.to_owned(), 18.0, name_color);

                    // Setup wallet connection text.
                    let conn_text = if let Some(id) = wallet.config.ext_conn_id {
                        let ext_conn_url = match ConnectionsConfig::ext_conn(id) {
                            None => ExternalConnection::DEFAULT_MAIN_URL.to_string(),
                            Some(ext_conn) => ext_conn.url
                        };
                        format!("{} {}", GLOBE_SIMPLE, ext_conn_url)
                    } else {
                        format!("{} {}", COMPUTER_TOWER, t!("network.node"))
                    };
                    View::ellipsize_text(ui, conn_text, 15.0, Colors::TEXT);
                    ui.add_space(1.0);

                    // Setup wallet status text.
                    let status_text = if wallet.is_open() {
                        if wallet.get_info().is_none() {
                            if wallet.loading_error() {
                                format!("{} {}", WARNING_CIRCLE, t!("loading_error"))
                            } else {
                                format!("{} {}", SPINNER, t!("loading"))
                            }
                        } else {
                            format!("{} {}", FOLDER_OPEN, t!("wallets.unlocked"))
                        }
                    } else {
                        format!("{} {}", FOLDER_LOCK, t!("wallets.locked"))
                    };
                    ui.label(RichText::new(status_text).size(15.0).color(Colors::GRAY));
                    ui.add_space(4.0);
                })
            });
        });
    }

    /// Draw floating button to show wallet creation [`Modal`].
    fn create_wallet_btn_ui(&mut self,
                            ui: &mut egui::Ui,
                            right_margin: f32,
                            cb: &dyn PlatformCallbacks) {
        egui::Window::new("create_wallet_button")
            .title_bar(false)
            .resizable(false)
            .collapsible(false)
            .anchor(Align2::RIGHT_BOTTOM, egui::Vec2::new(-6.0 - right_margin, -6.0))
            .frame(egui::Frame::default())
            .show(ui.ctx(), |ui| {
                View::circle_button(ui, PLUS, || {
                    self.creation_content.show_name_pass_modal(cb);
                });
            });
    }

    /// Show [`Modal`] to open selected wallet.
    pub fn show_open_wallet_modal(&mut self, cb: &dyn PlatformCallbacks) {
        // Reset modal values.
        self.hide_pass = true;
        self.pass_edit = String::from("");
        self.wrong_pass = false;
        // Show modal.
        Modal::new(OPEN_WALLET_MODAL)
            .position(ModalPosition::CenterTop)
            .title(t!("wallets.open"))
            .show();
        cb.show_keyboard();
    }

    /// Draw wallet opening [`Modal`] content.
    fn open_wallet_modal_ui(&mut self,
                            ui: &mut egui::Ui,
                            modal: &Modal,
                            cb: &dyn PlatformCallbacks) {
        ui.add_space(6.0);
        ui.vertical_centered(|ui| {
            ui.label(RichText::new(t!("wallets.pass"))
                .size(17.0)
                .color(Colors::GRAY));
            ui.add_space(10.0);

            StripBuilder::new(ui)
                .size(Size::exact(34.0))
                .vertical(|mut strip| {
                    strip.strip(|builder| {
                        builder
                            .size(Size::remainder())
                            .size(Size::exact(48.0))
                            .horizontal(|mut strip| {
                                strip.cell(|ui| {
                                    // Draw wallet password text edit.
                                    let pass_resp = egui::TextEdit::singleline(&mut self.pass_edit)
                                        .id(ui.id().with("wallet_pass_edit"))
                                        .font(TextStyle::Heading)
                                        .desired_width(ui.available_width())
                                        .cursor_at_end(true)
                                        .password(self.hide_pass)
                                        .ui(ui);
                                    pass_resp.request_focus();
                                    if pass_resp.clicked() {
                                        cb.show_keyboard();
                                    }
                                });
                                strip.cell(|ui| {
                                    ui.vertical_centered(|ui| {
                                        // Draw button to show/hide password.
                                        let eye_icon = if self.hide_pass { EYE } else { EYE_SLASH };
                                        View::button(ui, eye_icon.to_string(), Colors::WHITE, || {
                                            self.hide_pass = !self.hide_pass;
                                        });
                                    });
                                });
                            });
                    })
                });

            // Show information when password is empty.
            if self.pass_edit.is_empty() {
                ui.add_space(10.0);
                ui.label(RichText::new(t!("wallets.pass_empty"))
                    .size(17.0)
                    .color(Colors::INACTIVE_TEXT));
            } else if self.wrong_pass {
                ui.add_space(10.0);
                ui.label(RichText::new(t!("wallets.wrong_pass"))
                    .size(17.0)
                    .color(Colors::RED));
            }
            ui.add_space(12.0);
        });

        // Show modal buttons.
        ui.scope(|ui| {
            // Setup spacing between buttons.
            ui.spacing_mut().item_spacing = egui::Vec2::new(8.0, 0.0);

            ui.columns(2, |columns| {
                columns[0].vertical_centered_justified(|ui| {
                    View::button(ui, t!("modal.cancel"), Colors::WHITE, || {
                        // Close modal.
                        cb.hide_keyboard();
                        modal.close();
                    });
                });
                columns[1].vertical_centered_justified(|ui| {
                    // Callback for button to continue.
                    let mut on_continue = || {
                        if self.pass_edit.is_empty() {
                            return;
                        }
                        match self.wallets.open_selected(self.pass_edit.clone()) {
                            Ok(_) => {
                                // Clear values.
                                self.pass_edit = "".to_string();
                                self.wrong_pass = false;
                                self.hide_pass = true;
                                // Close modal.
                                cb.hide_keyboard();
                                modal.close();
                            }
                            Err(_) => self.wrong_pass = true
                        }
                    };

                    // Continue on Enter key press.
                    View::on_enter_key(ui, || {
                        (on_continue)();
                    });

                    View::button(ui, t!("continue"), Colors::WHITE, on_continue);
                });
            });
            ui.add_space(6.0);
        });
    }

    /// Handle Back key event.
    /// Return `false` when event was handled.
    pub fn on_back(&mut self) -> bool {
        let can_go_back = self.creation_content.can_go_back();
        if can_go_back {
            self.creation_content.back();
        }
        !can_go_back
    }
}

/// Check if it's possible to show [`WalletsContent`] and [`WalletContent`] panels at same time.
fn is_dual_panel_mode(ui: &mut egui::Ui, frame: &mut eframe::Frame) -> bool {
    let dual_panel_root = Root::is_dual_panel_mode(frame);
    let max_width = ui.available_width();
    dual_panel_root && max_width >= (Root::SIDE_PANEL_WIDTH * 2.0) + View::get_right_inset()
}