use crate::config::Settings;
use crate::meta_plugin::{MetaPlugin, MetaPluginType};
use crate::modes::common::settings_meta_plugin_types;
use clap::Command;
use log::debug;
use rusqlite::Connection;
use std::collections::HashMap;

pub struct MetaService;

impl MetaService {
    pub fn new() -> Self {
        Self
    }

    pub fn get_plugins(&self, cmd: &mut Command, settings: &Settings) -> Vec<Box<dyn MetaPlugin>> {
        debug!("META_SERVICE: get_plugins called");
        let meta_plugin_types: Vec<MetaPluginType> = settings_meta_plugin_types(cmd, settings);
        debug!("META_SERVICE: Meta plugin types from settings: {meta_plugin_types:?}");

        // Create plugins with their configuration
        let meta_plugins: Vec<Box<dyn MetaPlugin>> = meta_plugin_types
            .iter()
            .map(|meta_plugin_type| {
                debug!("META_SERVICE: Creating plugin: {meta_plugin_type:?}");

                // Get the plugin name using strum's Display implementation
                let plugin_name = meta_plugin_type.to_string();

                // Get options and outputs from settings
                let (options, outputs) = if let Some(meta_plugin_configs) = &settings.meta_plugins {
                    if let Some(config) = meta_plugin_configs.iter().find(|c| c.name == plugin_name)
                    {
                        // Convert options and outputs to the appropriate types
                        let options: std::collections::HashMap<String, serde_yaml::Value> = config
                            .options
                            .iter()
                            .map(|(k, v)| (k.clone(), v.clone()))
                            .collect();

                        let outputs: std::collections::HashMap<String, serde_yaml::Value> = config
                            .outputs
                            .iter()
                            .map(|(k, v)| (k.clone(), serde_yaml::Value::String(v.clone())))
                            .collect();

                        (Some(options), Some(outputs))
                    } else {
                        (None, None)
                    }
                } else {
                    (None, None)
                };

                crate::meta_plugin::get_meta_plugin(meta_plugin_type.clone(), options, outputs)
            })
            .collect();

        meta_plugins
    }

    pub fn initialize_plugins(
        &self,
        plugins: &mut [Box<dyn MetaPlugin>],
        conn: &Connection,
        item_id: i64,
    ) {
        // Check for duplicate output names before initializing plugins
        let mut output_names: std::collections::HashMap<String, Vec<String>> =
            std::collections::HashMap::new();

        for plugin in plugins.iter() {
            let plugin_name = plugin.meta_type().to_string();
            // For each plugin, collect all the output names it might write to
            for (internal_name, output_config) in plugin.outputs() {
                let output_name = match output_config {
                    serde_yaml::Value::String(remapped_name) => remapped_name.clone(),
                    serde_yaml::Value::Bool(true) => internal_name.clone(),
                    serde_yaml::Value::Bool(false) => continue, // This output is disabled
                    _ => internal_name.clone(), // Default to internal name for other types
                };

                // Only track outputs that will actually be written
                if !matches!(output_config, serde_yaml::Value::Bool(false)) {
                    output_names
                        .entry(output_name)
                        .or_default()
                        .push(plugin_name.clone());
                }
            }
        }

        // Print warnings for duplicate output names
        for (output_name, plugin_names) in &output_names {
            if plugin_names.len() > 1 {
                log::warn!(
                    "META_SERVICE: Output name '{}' is provided by multiple plugins: {}",
                    output_name,
                    plugin_names.join(", ")
                );
            }
        }

        for meta_plugin in plugins.iter_mut() {
            let response = meta_plugin.initialize();
            self.process_plugin_response(conn, item_id, &mut **meta_plugin, response);
        }
    }

    pub fn process_chunk(
        &self,
        plugins: &mut [Box<dyn MetaPlugin>],
        chunk: &[u8],
        conn: &Connection,
        item_id: i64,
    ) {
        for meta_plugin in plugins.iter_mut() {
            // Skip plugins that are already finalized
            if meta_plugin.is_finalized() {
                continue;
            }

            let response = meta_plugin.update(chunk);
            self.process_plugin_response(conn, item_id, &mut **meta_plugin, response.clone());

            // Set finalized flag if response indicates finalization
            if response.is_finalized {
                meta_plugin.set_finalized(true);
            }
        }
    }

    pub fn finalize_plugins(
        &self,
        plugins: &mut [Box<dyn MetaPlugin>],
        conn: &Connection,
        item_id: i64,
    ) {
        for meta_plugin in plugins.iter_mut() {
            // Skip plugins that are already finalized
            if meta_plugin.is_finalized() {
                continue;
            }

            let response = meta_plugin.finalize();
            self.process_plugin_response(conn, item_id, &mut **meta_plugin, response.clone());

            // Set finalized flag if response indicates finalization
            if response.is_finalized {
                meta_plugin.set_finalized(true);
            }
        }
    }

    /// Internal helper to process a meta plugin response and store metadata.
    ///
    /// Iterates over the metadata entries in the response and stores each in the database
    /// using `store_meta`. Logs warnings if storage fails.
    ///
    /// # Arguments
    ///
    /// * `conn` - Database connection.
    /// * `item_id` - Item ID to associate with the metadata.
    /// * `_plugin` - Reference to the plugin (unused).
    /// * `response` - The plugin response containing metadata.
    ///
    /// # Errors
    ///
    /// Logs warnings for individual storage failures but does not return errors.
    fn process_plugin_response(
        &self,
        conn: &Connection,
        item_id: i64,
        _plugin: &mut dyn MetaPlugin,
        response: crate::meta_plugin::MetaPluginResponse,
    ) {
        for meta_data in response.metadata {
            // The metadata has already been processed by the plugin, so we can use it directly
            // Save to database
            let db_meta = crate::db::Meta {
                id: item_id,
                name: meta_data.name,
                value: meta_data.value,
            };
            if let Err(e) = crate::db::store_meta(conn, db_meta) {
                log::warn!("META_SERVICE: Failed to store metadata: {e}");
            }
        }
    }

    /// Collects initial metadata from environment variables and hostname.
    ///
    /// Gathers metadata from `KEEP_META_*` environment variables and adds hostname
    /// if not already present.
    ///
    /// # Returns
    ///
    /// A `HashMap` of initial metadata key-value pairs.
    ///
    /// # Examples
    ///
    /// ```
    /// # use keep::services::MetaService;
    /// let service = MetaService::new();
    /// let initial_meta = service.collect_initial_meta();
    /// ```
    pub fn collect_initial_meta(&self) -> HashMap<String, String> {
        let mut item_meta: HashMap<String, String> = crate::modes::common::get_meta_from_env();

        if let Ok(hostname) = gethostname::gethostname().into_string()
            && !item_meta.contains_key("hostname")
        {
            item_meta.insert("hostname".to_string(), hostname);
        }
        item_meta
    }
}

impl Default for MetaService {
    /// Provides a default `MetaService` instance.
    ///
    /// # Returns
    ///
    /// A new `MetaService` via `new()`.
    fn default() -> Self {
        Self::new()
    }
}