//! # Userstyles 🎨
//!
//! > **Bauke's collection of userstyles.**

#![forbid(unsafe_code)]
#![warn(missing_docs, clippy::missing_docs_in_private_items)]

use serde::Deserialize;

/// All potential errors that could occur.
#[derive(Debug, thiserror::Error)]
pub enum Error {
  /// [`std::io`] errors.
  #[error(transparent)]
  Io(#[from] std::io::Error),

  /// [`serde_json`] errors.
  #[error(transparent)]
  Json(#[from] serde_json::Error),
}

/// All available userstyles as a const, to easily iterate over them.
pub const ALL_USERSTYLES: &[Userstyles] =
  &[Userstyles::TildesBaukula, Userstyles::TildesCompact];

/// All available userstyles.
#[derive(Debug)]
pub enum Userstyles {
  /// Tildes Baukula
  TildesBaukula,

  /// Tildes Compact
  TildesCompact,
}

/// Userstyle data.
#[derive(Debug, Deserialize)]
pub struct Userstyle {
  /// Compiled CSS.
  pub css: String,

  /// An optional image.
  pub image: Option<Vec<u8>>,

  /// Metadata of the userstyle.
  pub metadata: UserstyleMetadata,
}

/// Userstyle metadata.
#[derive(Debug, Deserialize)]
pub struct UserstyleMetadata {
  /// The name.
  pub name: String,

  /// The namespace.
  pub namespace: String,

  /// The version.
  pub version: String,

  /// The author.
  pub author: String,

  /// The description.
  pub description: String,

  /// The homepage URL.
  #[serde(rename = "homepageURL")]
  pub homepage_url: String,

  /// The update URL.
  #[serde(rename = "updateURL")]
  pub update_url: String,

  /// The license.
  pub license: String,

  /// The domain for `@-moz-document domain`.
  pub domain: String,
}

impl Userstyle {
  /// Formats a [`Userstyle`] in the expected `.user.css` format.
  pub fn format(&self) -> String {
    let mut css = String::new();
    for line in self.css.lines() {
      if line.is_empty() {
        continue;
      }

      css += &format!("  {}\n", line);
    }

    format!(
      r#"/* ==UserStyle==
@name        {name}
@namespace   {namespace}
@version     {version}
@author      {author}
@description {description}
@homepageURL {homepage_url}
@updateURL   {update_url}
@license     {license}
==/UserStyle== */

@-moz-document domain("{domain}") {{
{css}
}}
"#,
      name = self.metadata.name,
      namespace = self.metadata.namespace,
      version = self.metadata.version,
      author = self.metadata.author,
      description = self.metadata.description,
      homepage_url = self.metadata.homepage_url,
      update_url = self.metadata.update_url,
      license = self.metadata.license,
      domain = self.metadata.domain,
      css = css.trim_end(),
    )
  }

  /// Returns a [`Userstyle`] from a given `target` [`Userstyles`].
  pub fn load(target: &Userstyles) -> Result<Self, Error> {
    let (css, image, metadata) = match target {
      Userstyles::TildesBaukula => (
        include_str!("../target/userstyles/tildes-baukula.css"),
        Some(
          include_bytes!("tildes-baukula/images/tildes-baukula-logo.png")
            .to_vec(),
        ),
        include_str!("tildes-baukula/metadata.json"),
      ),
      Userstyles::TildesCompact => (
        include_str!("../target/userstyles/tildes-compact.css"),
        Some(
          include_bytes!("tildes-compact/images/tildes-compact-logo.png")
            .to_vec(),
        ),
        include_str!("tildes-compact/metadata.json"),
      ),
    };

    Ok(Self {
      css: css.to_string(),
      image,
      metadata: serde_json::from_str(metadata)?,
    })
  }
}

/// Assert that all metadata.json files parse successfully.
#[test]
fn test_metadata_parsing() {
  for target in ALL_USERSTYLES {
    assert!(Userstyle::load(target).is_ok());
  }
}