//! Plugin registry for managing loaded plugins

use std::path::PathBuf;

use anyhow::{Result, anyhow};
use pinakes_plugin_api::{PluginManifest, PluginMetadata};
use rustc_hash::FxHashMap;

use super::runtime::WasmPlugin;

/// A registered plugin with its metadata and runtime state
#[derive(Clone)]
pub struct RegisteredPlugin {
  pub id:            String,
  pub metadata:      PluginMetadata,
  pub wasm_plugin:   WasmPlugin,
  pub manifest:      PluginManifest,
  pub manifest_path: Option<PathBuf>,
  pub enabled:       bool,
}

/// Plugin registry maintains the state of all loaded plugins
pub struct PluginRegistry {
  /// Map of plugin ID to registered plugin
  plugins: FxHashMap<String, RegisteredPlugin>,
}

impl PluginRegistry {
  /// Create a new empty registry
  #[must_use]
  pub fn new() -> Self {
    Self {
      plugins: FxHashMap::default(),
    }
  }

  /// Register a new plugin
  ///
  /// # Errors
  ///
  /// Returns an error if a plugin with the same ID is already registered.
  pub fn register(&mut self, plugin: RegisteredPlugin) -> Result<()> {
    if self.plugins.contains_key(&plugin.id) {
      return Err(anyhow!("Plugin already registered: {}", plugin.id));
    }

    self.plugins.insert(plugin.id.clone(), plugin);
    Ok(())
  }

  /// Unregister a plugin by ID
  ///
  /// # Errors
  ///
  /// Returns an error if the plugin ID is not found.
  pub fn unregister(&mut self, plugin_id: &str) -> Result<()> {
    self
      .plugins
      .remove(plugin_id)
      .ok_or_else(|| anyhow!("Plugin not found: {plugin_id}"))?;
    Ok(())
  }

  /// Get a plugin by ID
  #[must_use]
  pub fn get(&self, plugin_id: &str) -> Option<&RegisteredPlugin> {
    self.plugins.get(plugin_id)
  }

  /// Get a mutable reference to a plugin by ID
  pub fn get_mut(&mut self, plugin_id: &str) -> Option<&mut RegisteredPlugin> {
    self.plugins.get_mut(plugin_id)
  }

  /// Check if a plugin is loaded
  #[must_use]
  pub fn is_loaded(&self, plugin_id: &str) -> bool {
    self.plugins.contains_key(plugin_id)
  }

  /// Check if a plugin is enabled. Returns `None` if the plugin is not found.
  #[must_use]
  pub fn is_enabled(&self, plugin_id: &str) -> Option<bool> {
    self.plugins.get(plugin_id).map(|p| p.enabled)
  }

  /// Enable a plugin
  ///
  /// # Errors
  ///
  /// Returns an error if the plugin ID is not found.
  pub fn enable(&mut self, plugin_id: &str) -> Result<()> {
    let plugin = self
      .plugins
      .get_mut(plugin_id)
      .ok_or_else(|| anyhow!("Plugin not found: {plugin_id}"))?;

    plugin.enabled = true;
    Ok(())
  }

  /// Disable a plugin
  ///
  /// # Errors
  ///
  /// Returns an error if the plugin ID is not found.
  pub fn disable(&mut self, plugin_id: &str) -> Result<()> {
    let plugin = self
      .plugins
      .get_mut(plugin_id)
      .ok_or_else(|| anyhow!("Plugin not found: {plugin_id}"))?;

    plugin.enabled = false;
    Ok(())
  }

  /// List all registered plugins
  #[must_use]
  pub fn list_all(&self) -> Vec<&RegisteredPlugin> {
    self.plugins.values().collect()
  }

  /// List all enabled plugins
  #[must_use]
  pub fn list_enabled(&self) -> Vec<&RegisteredPlugin> {
    self.plugins.values().filter(|p| p.enabled).collect()
  }

  /// Get plugins by kind (e.g., "`media_type`", "`metadata_extractor`")
  #[must_use]
  pub fn get_by_kind(&self, kind: &str) -> Vec<&RegisteredPlugin> {
    self
      .plugins
      .values()
      .filter(|p| p.manifest.plugin.kind.iter().any(|k| k == kind))
      .collect()
  }

  /// Get count of registered plugins
  #[must_use]
  pub fn count(&self) -> usize {
    self.plugins.len()
  }

  /// Get count of enabled plugins
  #[must_use]
  pub fn count_enabled(&self) -> usize {
    self.plugins.values().filter(|p| p.enabled).count()
  }
}

impl Default for PluginRegistry {
  fn default() -> Self {
    Self::new()
  }
}

#[cfg(test)]
mod tests {
  use pinakes_plugin_api::{Capabilities, manifest::ManifestCapabilities};
  use rustc_hash::FxHashMap;

  use super::*;

  fn create_test_plugin(id: &str, kind: Vec<String>) -> RegisteredPlugin {
    let manifest = PluginManifest {
      plugin:       pinakes_plugin_api::manifest::PluginInfo {
        name: id.to_string(),
        version: "1.0.0".to_string(),
        api_version: "1.0".to_string(),
        author: Some("Test".to_string()),
        description: Some("Test plugin".to_string()),
        homepage: None,
        license: None,
        kind,
        binary: pinakes_plugin_api::manifest::PluginBinary {
          wasm:       "test.wasm".to_string(),
          entrypoint: None,
        },
        dependencies: vec![],
        priority: 0,
      },
      capabilities: ManifestCapabilities::default(),
      config:       FxHashMap::default(),
      ui:           Default::default(),
    };

    RegisteredPlugin {
      id: id.to_string(),
      metadata: PluginMetadata {
        id:                    id.to_string(),
        name:                  id.to_string(),
        version:               "1.0.0".to_string(),
        author:                "Test".to_string(),
        description:           "Test plugin".to_string(),
        api_version:           "1.0".to_string(),
        capabilities_required: Capabilities::default(),
      },
      wasm_plugin: WasmPlugin::default(),
      manifest,
      manifest_path: None,
      enabled: true,
    }
  }

  #[test]
  fn test_registry_register_and_get() {
    let mut registry = PluginRegistry::new();
    let plugin =
      create_test_plugin("test-plugin", vec!["media_type".to_string()]);

    registry.register(plugin).unwrap();

    assert!(registry.is_loaded("test-plugin"));
    assert!(registry.get("test-plugin").is_some());
  }

  #[test]
  fn test_registry_duplicate_register() {
    let mut registry = PluginRegistry::new();
    let plugin =
      create_test_plugin("test-plugin", vec!["media_type".to_string()]);

    registry.register(plugin.clone()).unwrap();
    let result = registry.register(plugin);

    assert!(result.is_err());
  }

  #[test]
  fn test_registry_unregister() {
    let mut registry = PluginRegistry::new();
    let plugin =
      create_test_plugin("test-plugin", vec!["media_type".to_string()]);

    registry.register(plugin).unwrap();
    registry.unregister("test-plugin").unwrap();

    assert!(!registry.is_loaded("test-plugin"));
  }

  #[test]
  fn test_registry_enable_disable() {
    let mut registry = PluginRegistry::new();
    let plugin =
      create_test_plugin("test-plugin", vec!["media_type".to_string()]);

    registry.register(plugin).unwrap();
    assert_eq!(registry.is_enabled("test-plugin"), Some(true));

    registry.disable("test-plugin").unwrap();
    assert_eq!(registry.is_enabled("test-plugin"), Some(false));

    registry.enable("test-plugin").unwrap();
    assert_eq!(registry.is_enabled("test-plugin"), Some(true));

    assert_eq!(registry.is_enabled("nonexistent"), None);
  }

  #[test]
  fn test_registry_get_by_kind() {
    let mut registry = PluginRegistry::new();

    registry
      .register(create_test_plugin("plugin1", vec![
        "media_type".to_string(),
      ]))
      .unwrap();
    registry
      .register(create_test_plugin("plugin2", vec![
        "metadata_extractor".to_string(),
      ]))
      .unwrap();
    registry
      .register(create_test_plugin("plugin3", vec![
        "media_type".to_string(),
      ]))
      .unwrap();

    let media_type_plugins = registry.get_by_kind("media_type");
    assert_eq!(media_type_plugins.len(), 2);

    let extractor_plugins = registry.get_by_kind("metadata_extractor");
    assert_eq!(extractor_plugins.len(), 1);
  }

  #[test]
  fn test_registry_counts() {
    let mut registry = PluginRegistry::new();

    registry
      .register(create_test_plugin("plugin1", vec![
        "media_type".to_string(),
      ]))
      .unwrap();
    registry
      .register(create_test_plugin("plugin2", vec![
        "media_type".to_string(),
      ]))
      .unwrap();

    assert_eq!(registry.count(), 2);
    assert_eq!(registry.count_enabled(), 2);

    registry.disable("plugin1").unwrap();
    assert_eq!(registry.count(), 2);
    assert_eq!(registry.count_enabled(), 1);
  }
}