// Copyright 2024 System76 <info@system76.com>
// SPDX-License-Identifier: MPL-2.0

//! Configurations available to libcosmic applications.

use crate::cosmic_theme::Density;
use cosmic_config::cosmic_config_derive::CosmicConfigEntry;
use cosmic_config::{Config, CosmicConfigEntry};
use serde::{Deserialize, Serialize};
use std::collections::BTreeSet;
use std::sync::{LazyLock, RwLock};

/// ID for the `CosmicTk` config.
pub const ID: &str = "com.system76.CosmicTk";

const MONO_FAMILY_DEFAULT: &str = "Noto Sans Mono";
const SANS_FAMILY_DEFAULT: &str = "Open Sans";

pub static COSMIC_TK: LazyLock<RwLock<CosmicTk>> = LazyLock::new(|| {
    RwLock::new(
        CosmicTk::config()
            .map(|c| {
                CosmicTk::get_entry(&c).unwrap_or_else(|(errors, mode)| {
                    for why in errors.into_iter().filter(cosmic_config::Error::is_err) {
                        if let cosmic_config::Error::GetKey(_, err) = &why {
                            if err.kind() == std::io::ErrorKind::NotFound {
                                // No system default config installed; don't error
                                continue;
                            }
                        }
                        tracing::error!(?why, "CosmicTk config entry error");
                    }
                    mode
                })
            })
            .unwrap_or_default(),
    )
});

/// Apply the theme to other toolkits.
#[allow(clippy::missing_panics_doc)]
pub fn apply_theme_global() -> bool {
    COSMIC_TK.read().unwrap().apply_theme_global
}

/// Show minimize button in window header.
#[allow(clippy::missing_panics_doc)]
pub fn show_minimize() -> bool {
    COSMIC_TK.read().unwrap().show_minimize
}

/// Show maximize button in window header.
#[allow(clippy::missing_panics_doc)]
pub fn show_maximize() -> bool {
    COSMIC_TK.read().unwrap().show_maximize
}

/// Preferred icon theme.
#[allow(clippy::missing_panics_doc)]
pub fn icon_theme() -> String {
    COSMIC_TK.read().unwrap().icon_theme.clone()
}

/// Density of CSD/SSD header bars.
#[allow(clippy::missing_panics_doc)]
pub fn header_size() -> Density {
    COSMIC_TK.read().unwrap().header_size
}

/// Interface density.
#[allow(clippy::missing_panics_doc)]
pub fn interface_density() -> Density {
    COSMIC_TK.read().unwrap().interface_density
}

#[allow(clippy::missing_panics_doc)]
pub fn interface_font() -> FontConfig {
    COSMIC_TK.read().unwrap().interface_font.clone()
}

#[allow(clippy::missing_panics_doc)]
pub fn monospace_font() -> FontConfig {
    COSMIC_TK.read().unwrap().monospace_font.clone()
}

#[derive(Clone, CosmicConfigEntry, Debug, Eq, PartialEq)]
#[version = 1]
pub struct CosmicTk {
    /// Apply the theme to other toolkits.
    pub apply_theme_global: bool,

    /// Show minimize button in window header.
    pub show_minimize: bool,

    /// Show maximize button in window header.
    pub show_maximize: bool,

    /// Preferred icon theme.
    pub icon_theme: String,

    /// Density of CSD/SSD header bars.
    pub header_size: Density,

    /// Interface density.
    pub interface_density: Density,

    /// Interface font family
    pub interface_font: FontConfig,

    /// Mono font family
    pub monospace_font: FontConfig,
}

impl Default for CosmicTk {
    fn default() -> Self {
        Self {
            apply_theme_global: false,
            show_minimize: true,
            show_maximize: true,
            icon_theme: String::from("Cosmic"),
            header_size: Density::Standard,
            interface_density: Density::Standard,
            interface_font: FontConfig {
                family: SANS_FAMILY_DEFAULT.to_owned(),
                weight: iced::font::Weight::Normal,
                stretch: iced::font::Stretch::Normal,
                style: iced::font::Style::Normal,
            },
            monospace_font: FontConfig {
                family: MONO_FAMILY_DEFAULT.to_owned(),
                weight: iced::font::Weight::Normal,
                stretch: iced::font::Stretch::Normal,
                style: iced::font::Style::Normal,
            },
        }
    }
}

impl CosmicTk {
    #[inline]
    pub fn config() -> Result<Config, cosmic_config::Error> {
        Config::new(ID, Self::VERSION)
    }
}

#[derive(Clone, Debug, Eq, PartialEq, Deserialize, Serialize)]
pub struct FontConfig {
    pub family: String,
    pub weight: iced::font::Weight,
    pub stretch: iced::font::Stretch,
    pub style: iced::font::Style,
}

impl From<FontConfig> for iced::Font {
    fn from(font: FontConfig) -> Self {
        /// Stores static strings of the family names for `iced::Font` compatibility.
        static FAMILY_MAP: LazyLock<RwLock<BTreeSet<&'static str>>> =
            LazyLock::new(RwLock::default);

        let read_guard = FAMILY_MAP.read().unwrap();
        let name: Option<&'static str> = read_guard.get(font.family.as_str()).copied();
        drop(read_guard);

        let name = name.unwrap_or_else(|| {
            let value: &'static str = font.family.clone().leak();
            FAMILY_MAP.write().unwrap().insert(value);
            value
        });

        Self {
            family: iced::font::Family::Name(name),
            weight: font.weight,
            stretch: font.stretch,
            style: font.style,
        }
    }
}