//! Provides constructs for the Zed app version and release channel.

#![deny(missing_docs)]

use std::env;

use gpui::{AppContext, Global, SemanticVersion};
use once_cell::sync::Lazy;

static RELEASE_CHANNEL_NAME: Lazy<String> = if cfg!(debug_assertions) {
    Lazy::new(|| {
        env::var("ZED_RELEASE_CHANNEL")
            .unwrap_or_else(|_| include_str!("../../zed/RELEASE_CHANNEL").trim().to_string())
    })
} else {
    Lazy::new(|| include_str!("../../zed/RELEASE_CHANNEL").trim().to_string())
};

#[doc(hidden)]
pub static RELEASE_CHANNEL: Lazy<ReleaseChannel> =
    Lazy::new(|| match RELEASE_CHANNEL_NAME.as_str() {
        "dev" => ReleaseChannel::Dev,
        "nightly" => ReleaseChannel::Nightly,
        "preview" => ReleaseChannel::Preview,
        "stable" => ReleaseChannel::Stable,
        _ => panic!("invalid release channel {}", *RELEASE_CHANNEL_NAME),
    });

/// The Git commit SHA that Zed was built at.
#[derive(Clone)]
pub struct AppCommitSha(pub String);

struct GlobalAppCommitSha(AppCommitSha);

impl Global for GlobalAppCommitSha {}

impl AppCommitSha {
    /// Returns the global [`AppCommitSha`], if one is set.
    pub fn try_global(cx: &AppContext) -> Option<AppCommitSha> {
        cx.try_global::<GlobalAppCommitSha>()
            .map(|sha| sha.0.clone())
    }

    /// Sets the global [`AppCommitSha`].
    pub fn set_global(sha: AppCommitSha, cx: &mut AppContext) {
        cx.set_global(GlobalAppCommitSha(sha))
    }
}

struct GlobalAppVersion(SemanticVersion);

impl Global for GlobalAppVersion {}

/// The version of Zed.
pub struct AppVersion;

impl AppVersion {
    /// Initializes the global [`AppVersion`].
    ///
    /// Attempts to read the version number from the following locations, in order:
    /// 1. the `ZED_APP_VERSION` environment variable,
    /// 2. the [`AppContext::app_metadata`],
    /// 3. the passed in `pkg_version`.
    pub fn init(pkg_version: &str, cx: &mut AppContext) {
        let version = if let Ok(from_env) = env::var("ZED_APP_VERSION") {
            from_env.parse().expect("invalid ZED_APP_VERSION")
        } else {
            cx.app_metadata()
                .app_version
                .unwrap_or_else(|| pkg_version.parse().expect("invalid version in Cargo.toml"))
        };
        cx.set_global(GlobalAppVersion(version))
    }

    /// Returns the global version number.
    pub fn global(cx: &AppContext) -> SemanticVersion {
        cx.global::<GlobalAppVersion>().0
    }
}

/// A Zed release channel.
#[derive(Debug, Copy, Clone, PartialEq, Eq, Default)]
pub enum ReleaseChannel {
    /// The development release channel.
    ///
    /// Used for local debug builds of Zed.
    #[default]
    Dev,

    /// The Nightly release channel.
    Nightly,

    /// The Preview release channel.
    Preview,

    /// The Stable release channel.
    Stable,
}

struct GlobalReleaseChannel(ReleaseChannel);

impl Global for GlobalReleaseChannel {}

/// Initializes the release channel.
pub fn init(pkg_version: &str, cx: &mut AppContext) {
    AppVersion::init(pkg_version, cx);
    cx.set_global(GlobalReleaseChannel(*RELEASE_CHANNEL))
}

impl ReleaseChannel {
    /// Returns the global [`ReleaseChannel`].
    pub fn global(cx: &AppContext) -> Self {
        cx.global::<GlobalReleaseChannel>().0
    }

    /// Returns the global [`ReleaseChannel`], if one is set.
    pub fn try_global(cx: &AppContext) -> Option<Self> {
        cx.try_global::<GlobalReleaseChannel>()
            .map(|channel| channel.0)
    }

    /// Returns the display name for this [`ReleaseChannel`].
    pub fn display_name(&self) -> &'static str {
        match self {
            ReleaseChannel::Dev => "Zed Dev",
            ReleaseChannel::Nightly => "Zed Nightly",
            ReleaseChannel::Preview => "Zed Preview",
            ReleaseChannel::Stable => "Zed",
        }
    }

    /// Returns the programmatic name for this [`ReleaseChannel`].
    pub fn dev_name(&self) -> &'static str {
        match self {
            ReleaseChannel::Dev => "dev",
            ReleaseChannel::Nightly => "nightly",
            ReleaseChannel::Preview => "preview",
            ReleaseChannel::Stable => "stable",
        }
    }

    /// Returns the query parameter for this [`ReleaseChannel`].
    pub fn release_query_param(&self) -> Option<&'static str> {
        match self {
            Self::Dev => None,
            Self::Nightly => Some("nightly=1"),
            Self::Preview => Some("preview=1"),
            Self::Stable => None,
        }
    }
}