mod keymap_file;

use anyhow::Result;
use gpui::{
    font_cache::{FamilyId, FontCache},
    AssetSource,
};
use schemars::{
    gen::{SchemaGenerator, SchemaSettings},
    schema::{InstanceType, ObjectValidation, Schema, SchemaObject, SingleOrVec},
    JsonSchema,
};
use serde::{de::DeserializeOwned, Deserialize};
use serde_json::Value;
use std::{collections::HashMap, num::NonZeroU32, str, sync::Arc};
use theme::{Theme, ThemeRegistry};
use util::ResultExt as _;

pub use keymap_file::{keymap_file_json_schema, KeymapFileContent};

#[derive(Clone)]
pub struct Settings {
    pub projects_online_by_default: bool,
    pub buffer_font_family: FamilyId,
    pub buffer_font_size: f32,
    pub default_buffer_font_size: f32,
    pub hover_popover_enabled: bool,
    pub show_completions_on_input: bool,
    pub vim_mode: bool,
    pub autosave: Autosave,
    pub editor_defaults: EditorSettings,
    pub editor_overrides: EditorSettings,
    pub language_defaults: HashMap<Arc<str>, EditorSettings>,
    pub language_overrides: HashMap<Arc<str>, EditorSettings>,
    pub theme: Arc<Theme>,
}

#[derive(Clone, Debug, Default, Deserialize, JsonSchema)]
pub struct EditorSettings {
    pub tab_size: Option<NonZeroU32>,
    pub hard_tabs: Option<bool>,
    pub soft_wrap: Option<SoftWrap>,
    pub preferred_line_length: Option<u32>,
    pub format_on_save: Option<FormatOnSave>,
    pub enable_language_server: Option<bool>,
}

#[derive(Copy, Clone, Debug, Deserialize, PartialEq, Eq, JsonSchema)]
#[serde(rename_all = "snake_case")]
pub enum SoftWrap {
    None,
    EditorWidth,
    PreferredLineLength,
}

#[derive(Clone, Debug, Deserialize, PartialEq, Eq, JsonSchema)]
#[serde(rename_all = "snake_case")]
pub enum FormatOnSave {
    Off,
    LanguageServer,
    External {
        command: String,
        arguments: Vec<String>,
    },
}

#[derive(Copy, Clone, Debug, Deserialize, PartialEq, Eq, JsonSchema)]
#[serde(rename_all = "snake_case")]
pub enum Autosave {
    Off,
    AfterDelay { milliseconds: u64 },
    OnFocusChange,
    OnWindowChange,
}

#[derive(Clone, Debug, Default, Deserialize, JsonSchema)]
pub struct SettingsFileContent {
    #[serde(default)]
    pub projects_online_by_default: Option<bool>,
    #[serde(default)]
    pub buffer_font_family: Option<String>,
    #[serde(default)]
    pub buffer_font_size: Option<f32>,
    #[serde(default)]
    pub hover_popover_enabled: Option<bool>,
    #[serde(default)]
    pub show_completions_on_input: Option<bool>,
    #[serde(default)]
    pub vim_mode: Option<bool>,
    #[serde(default)]
    pub autosave: Option<Autosave>,
    #[serde(flatten)]
    pub editor: EditorSettings,
    #[serde(default)]
    #[serde(alias = "language_overrides")]
    pub languages: HashMap<Arc<str>, EditorSettings>,
    #[serde(default)]
    pub theme: Option<String>,
}

impl Settings {
    pub fn defaults(
        assets: impl AssetSource,
        font_cache: &FontCache,
        themes: &ThemeRegistry,
    ) -> Self {
        fn required<T>(value: Option<T>) -> Option<T> {
            assert!(value.is_some(), "missing default setting value");
            value
        }

        let defaults: SettingsFileContent = parse_json_with_comments(
            str::from_utf8(assets.load("settings/default.json").unwrap().as_ref()).unwrap(),
        )
        .unwrap();

        Self {
            buffer_font_family: font_cache
                .load_family(&[defaults.buffer_font_family.as_ref().unwrap()])
                .unwrap(),
            buffer_font_size: defaults.buffer_font_size.unwrap(),
            default_buffer_font_size: defaults.buffer_font_size.unwrap(),
            hover_popover_enabled: defaults.hover_popover_enabled.unwrap(),
            show_completions_on_input: defaults.show_completions_on_input.unwrap(),
            projects_online_by_default: defaults.projects_online_by_default.unwrap(),
            vim_mode: defaults.vim_mode.unwrap(),
            autosave: defaults.autosave.unwrap(),
            editor_defaults: EditorSettings {
                tab_size: required(defaults.editor.tab_size),
                hard_tabs: required(defaults.editor.hard_tabs),
                soft_wrap: required(defaults.editor.soft_wrap),
                preferred_line_length: required(defaults.editor.preferred_line_length),
                format_on_save: required(defaults.editor.format_on_save),
                enable_language_server: required(defaults.editor.enable_language_server),
            },
            language_defaults: defaults.languages,
            editor_overrides: Default::default(),
            language_overrides: Default::default(),
            theme: themes.get(&defaults.theme.unwrap()).unwrap(),
        }
    }

    pub fn set_user_settings(
        &mut self,
        data: SettingsFileContent,
        theme_registry: &ThemeRegistry,
        font_cache: &FontCache,
    ) {
        if let Some(value) = &data.buffer_font_family {
            if let Some(id) = font_cache.load_family(&[value]).log_err() {
                self.buffer_font_family = id;
            }
        }
        if let Some(value) = &data.theme {
            if let Some(theme) = theme_registry.get(&value.to_string()).log_err() {
                self.theme = theme;
            }
        }

        merge(
            &mut self.projects_online_by_default,
            data.projects_online_by_default,
        );
        merge(&mut self.buffer_font_size, data.buffer_font_size);
        merge(&mut self.default_buffer_font_size, data.buffer_font_size);
        merge(&mut self.hover_popover_enabled, data.hover_popover_enabled);
        merge(
            &mut self.show_completions_on_input,
            data.show_completions_on_input,
        );
        merge(&mut self.vim_mode, data.vim_mode);
        merge(&mut self.autosave, data.autosave);

        self.editor_overrides = data.editor;
        self.language_overrides = data.languages;
    }

    pub fn with_language_defaults(
        mut self,
        language_name: impl Into<Arc<str>>,
        overrides: EditorSettings,
    ) -> Self {
        self.language_defaults
            .insert(language_name.into(), overrides);
        self
    }

    pub fn tab_size(&self, language: Option<&str>) -> NonZeroU32 {
        self.language_setting(language, |settings| settings.tab_size)
    }

    pub fn hard_tabs(&self, language: Option<&str>) -> bool {
        self.language_setting(language, |settings| settings.hard_tabs)
    }

    pub fn soft_wrap(&self, language: Option<&str>) -> SoftWrap {
        self.language_setting(language, |settings| settings.soft_wrap)
    }

    pub fn preferred_line_length(&self, language: Option<&str>) -> u32 {
        self.language_setting(language, |settings| settings.preferred_line_length)
    }

    pub fn format_on_save(&self, language: Option<&str>) -> FormatOnSave {
        self.language_setting(language, |settings| settings.format_on_save.clone())
    }

    pub fn enable_language_server(&self, language: Option<&str>) -> bool {
        self.language_setting(language, |settings| settings.enable_language_server)
    }

    fn language_setting<F, R>(&self, language: Option<&str>, f: F) -> R
    where
        F: Fn(&EditorSettings) -> Option<R>,
    {
        None.or_else(|| language.and_then(|l| self.language_overrides.get(l).and_then(&f)))
            .or_else(|| f(&self.editor_overrides))
            .or_else(|| language.and_then(|l| self.language_defaults.get(l).and_then(&f)))
            .or_else(|| f(&self.editor_defaults))
            .expect("missing default")
    }

    #[cfg(any(test, feature = "test-support"))]
    pub fn test(cx: &gpui::AppContext) -> Settings {
        Settings {
            buffer_font_family: cx.font_cache().load_family(&["Monaco"]).unwrap(),
            buffer_font_size: 14.,
            default_buffer_font_size: 14.,
            hover_popover_enabled: true,
            show_completions_on_input: true,
            vim_mode: false,
            autosave: Autosave::Off,
            editor_defaults: EditorSettings {
                tab_size: Some(4.try_into().unwrap()),
                hard_tabs: Some(false),
                soft_wrap: Some(SoftWrap::None),
                preferred_line_length: Some(80),
                format_on_save: Some(FormatOnSave::LanguageServer),
                enable_language_server: Some(true),
            },
            editor_overrides: Default::default(),
            language_defaults: Default::default(),
            language_overrides: Default::default(),
            projects_online_by_default: true,
            theme: gpui::fonts::with_font_cache(cx.font_cache().clone(), || Default::default()),
        }
    }

    #[cfg(any(test, feature = "test-support"))]
    pub fn test_async(cx: &mut gpui::TestAppContext) {
        cx.update(|cx| {
            let settings = Self::test(cx);
            cx.set_global(settings.clone());
        });
    }
}

pub fn settings_file_json_schema(
    theme_names: Vec<String>,
    language_names: &[String],
) -> serde_json::Value {
    let settings = SchemaSettings::draft07().with(|settings| {
        settings.option_add_null_type = false;
    });
    let generator = SchemaGenerator::new(settings);
    let mut root_schema = generator.into_root_schema_for::<SettingsFileContent>();

    // Create a schema for a theme name.
    let theme_name_schema = SchemaObject {
        instance_type: Some(SingleOrVec::Single(Box::new(InstanceType::String))),
        enum_values: Some(
            theme_names
                .into_iter()
                .map(|name| Value::String(name))
                .collect(),
        ),
        ..Default::default()
    };

    // Create a schema for a 'languages overrides' object, associating editor
    // settings with specific langauges.
    assert!(root_schema.definitions.contains_key("EditorSettings"));
    let languages_object_schema = SchemaObject {
        instance_type: Some(SingleOrVec::Single(Box::new(InstanceType::Object))),
        object: Some(Box::new(ObjectValidation {
            properties: language_names
                .iter()
                .map(|name| {
                    (
                        name.clone(),
                        Schema::new_ref("#/definitions/EditorSettings".into()),
                    )
                })
                .collect(),
            ..Default::default()
        })),
        ..Default::default()
    };

    // Add these new schemas as definitions, and modify properties of the root
    // schema to reference them.
    root_schema.definitions.extend([
        ("ThemeName".into(), theme_name_schema.into()),
        ("Languages".into(), languages_object_schema.into()),
    ]);
    root_schema
        .schema
        .object
        .as_mut()
        .unwrap()
        .properties
        .extend([
            (
                "theme".to_owned(),
                Schema::new_ref("#/definitions/ThemeName".into()),
            ),
            (
                "languages".to_owned(),
                Schema::new_ref("#/definitions/Languages".into()),
            ),
            // For backward compatibility
            (
                "language_overrides".to_owned(),
                Schema::new_ref("#/definitions/Languages".into()),
            ),
        ]);

    serde_json::to_value(root_schema).unwrap()
}

fn merge<T: Copy>(target: &mut T, value: Option<T>) {
    if let Some(value) = value {
        *target = value;
    }
}

pub fn parse_json_with_comments<T: DeserializeOwned>(content: &str) -> Result<T> {
    Ok(serde_json::from_reader(
        json_comments::CommentSettings::c_style().strip_comments(content.as_bytes()),
    )?)
}