use crate::compression_engine::CompressionType;
/// Common utilities shared across different modes in the Keep application.
///
/// This module provides helper functions for formatting, configuration parsing,
/// table creation, and environment variable handling used by various CLI modes.
///
/// # Usage
///
/// These utilities are typically used internally by mode implementations:
///
/// ```
/// # use keep::modes::common::{format_size, OutputFormat};
/// let formatted = format_size(1024, true); // "1.0K"
/// // let format = OutputFormat::from_str("json")?;
/// ```
use crate::config;
use crate::meta_plugin::MetaPluginType;
use clap::Command;
use clap::error::ErrorKind;
use comfy_table::{ContentArrangement, Table};
use log::debug;
use regex::Regex;
use std::collections::HashMap;
use std::env;
use std::io::IsTerminal;
use std::str::FromStr;
use strum::IntoEnumIterator;

#[derive(Debug, Clone, strum::EnumString, strum::Display, PartialEq)]
#[strum(ascii_case_insensitive)]
/// Enum representing supported output formats for structured data.
///
/// Used to determine how to display lists, info, and status information in CLI modes.
/// Defaults to Table for human-readable output; JSON/YAML for machine parsing.
///
/// # Variants
///
/// * `Table` - Formatted table output (default).
/// * `Json` - JSON structured output.
/// * `Yaml` - YAML structured output.
///
/// # Examples
///
/// ```
/// # use keep::modes::common::OutputFormat;
/// # use std::str::FromStr;
/// assert_eq!(OutputFormat::from_str("json").unwrap(), OutputFormat::Json);
/// ```
pub enum OutputFormat {
    Table,
    Json,
    Yaml,
}

/// Extracts metadata from KEEP_META_* environment variables.
///
/// Scans environment for variables prefixed with KEEP_META_ and extracts
/// key-value pairs for initial item metadata. Ignores KEEP_META_PLUGINS.
///
/// # Returns
///
/// `HashMap<String, String>` - Metadata from environment variables, with keys in uppercase without prefix.
///
/// # Errors
///
/// None; silently ignores non-matching vars and PLUGINS.
///
/// # Examples
///
/// ```ignore
/// use std::env;
/// env::set_var("KEEP_META_COMMAND", "ls -la");
/// let meta = keep::modes::common::get_meta_from_env();
/// assert_eq!(meta.get("COMMAND"), Some(&"ls -la".to_string()));
/// ```
pub fn get_meta_from_env() -> HashMap<String, String> {
    debug!("COMMON: Getting meta from KEEP_META_*");
    let re = Regex::new(r"^KEEP_META_(.+)$").unwrap();
    let mut meta_env: HashMap<String, String> = HashMap::new();
    for (key, value) in env::vars() {
        if let Some(meta_name_caps) = re.captures(key.as_str()) {
            let name = String::from(meta_name_caps.get(1).unwrap().as_str());
            // Ignore KEEP_META_PLUGINS
            if name != "PLUGINS" {
                debug!("COMMON: Found meta: {}={}", name.clone(), value.clone());
                meta_env.insert(name, value.clone());
            }
        }
    }
    meta_env
}

/// Formats a file size in bytes to human-readable or raw format.
///
/// Uses the humansize crate for human-readable output with decimal units (KB, MB, etc.).
///
/// # Arguments
///
/// * `size` - Size in bytes as u64.
/// * `human_readable` - If true, use units like KB, MB; otherwise, raw bytes as string.
///
/// # Returns
///
/// `String` - Formatted size string, e.g., "1.0K" or "1024".
///
/// # Examples
///
/// ```
/// # use keep::modes::common::format_size;
/// let raw = format_size(1024, false); // "1024"
/// let human = format_size(1024, true); // "1.0K"
/// ```
pub fn format_size(size: u64, human_readable: bool) -> String {
    match human_readable {
        true => humansize::format_size(size, humansize::DECIMAL),
        false => size.to_string(),
    }
}

#[derive(Debug, Eq, PartialEq, Clone, strum::EnumIter, strum::Display)]
#[strum(ascii_case_insensitive)]
/// Enum representing column types for table display.
///
/// Defines standard and meta columns for list/info modes. Supports "meta:<name>" for specific metadata columns.
///
/// # Variants
///
/// * `Id` - Item ID column.
/// * `Time` - Timestamp column.
/// * `Size` - Content size column.
/// * `Compression` - Compression type column.
/// * `FileSize` - On-disk file size column.
/// * `FilePath` - File path column.
/// * `Tags` - Tags column.
/// * `Meta` - Metadata column (with sub-type via string parsing).
///
/// # Examples
///
/// ```
/// # use keep::modes::common::ColumnType;
/// # use std::str::FromStr;
/// assert_eq!(ColumnType::from_str("id").unwrap(), ColumnType::Id);
/// assert_eq!(ColumnType::from_str("meta:hostname").unwrap(), ColumnType::Meta);
/// ```
pub enum ColumnType {
    Id,
    Time,
    Size,
    Compression,
    FileSize,
    FilePath,
    Tags,
    Meta,
}

impl std::str::FromStr for ColumnType {
    type Err = anyhow::Error;

    fn from_str(s: &str) -> anyhow::Result<Self> {
        let lower_s = s.to_lowercase();
        if s.starts_with("meta:") {
            Ok(ColumnType::Meta)
        } else {
            for variant in ColumnType::iter() {
                if variant.to_string().to_lowercase() == lower_s {
                    return Ok(variant);
                }
            }
            Err(anyhow::anyhow!("Invalid column type: {}", s))
        }
    }
}

/// Extracts configured meta plugin types from settings and command.
///
/// Handles comma-separated plugin names and validates against registered types.
///
/// # Arguments
///
/// * `cmd` - Mutable Clap command for error reporting.
/// * `settings` - Application settings with plugin config.
///
/// # Returns
///
/// `Vec<MetaPluginType>` - List of enabled plugin types.
///
/// # Panics
///
/// Exits via Clap error if unknown plugin type specified.
pub fn settings_meta_plugin_types(
    cmd: &mut Command,
    settings: &config::Settings,
) -> Vec<MetaPluginType> {
    let mut meta_plugin_types = Vec::new();

    // Handle comma-separated values in each meta_plugins argument
    for meta_plugin_names_str in &settings.meta_plugins_names() {
        let meta_plugin_names: Vec<&str> = meta_plugin_names_str.split(',').collect();

        for name in meta_plugin_names {
            let trimmed_name = name.trim();
            if trimmed_name.is_empty() {
                continue;
            }

            // Try to find the MetaPluginType by meta name
            let mut found = false;
            for meta_plugin_type in MetaPluginType::iter() {
                if let Ok(meta_plugin) =
                    crate::meta_plugin::get_meta_plugin(meta_plugin_type.clone(), None, None)
                {
                    if meta_plugin.meta_type().to_string() == trimmed_name {
                        meta_plugin_types.push(meta_plugin_type);
                        found = true;
                        break;
                    }
                }
            }

            if !found {
                cmd.error(
                    ErrorKind::InvalidValue,
                    format!("Unknown meta plugin type: {trimmed_name}"),
                )
                .exit();
            }
        }
    }

    meta_plugin_types
}

/// Determines compression type from settings and command arguments.
///
/// Validates the compression name and returns the corresponding enum variant.
///
/// # Arguments
///
/// * `cmd` - Mutable Clap command for error reporting.
/// * `settings` - Application settings.
///
/// # Returns
///
/// `CompressionType` - The resolved compression type.
///
/// # Panics
///
/// Exits via Clap error if invalid compression specified.
pub fn settings_compression_type(
    cmd: &mut Command,
    settings: &config::Settings,
) -> CompressionType {
    let compression_name = settings
        .compression()
        .unwrap_or(CompressionType::LZ4.to_string());

    let compression_type_opt = CompressionType::from_str(&compression_name);
    if compression_type_opt.is_err() {
        cmd.error(
            ErrorKind::InvalidValue,
            format!("Invalid compression algorithm '{compression_name}'. Supported algorithms: lz4, gzip, xz, zstd"),
        )
        .exit();
    }

    compression_type_opt.unwrap()
}

/// Parses output format from settings.
///
/// Defaults to `Table` if not specified or invalid. Uses case-insensitive string parsing.
///
/// # Arguments
///
/// * `settings` - Application settings with optional output_format field.
///
/// # Returns
///
/// `OutputFormat` - Parsed enum variant or Table as default.
///
/// # Examples
///
/// ```
/// # use keep::modes::common::{settings_output_format, OutputFormat};
/// // Example usage requires a Settings instance
/// // let format = settings_output_format(&settings);
/// ```
pub fn settings_output_format(settings: &config::Settings) -> OutputFormat {
    settings
        .output_format
        .as_ref()
        .and_then(|s| OutputFormat::from_str(s).ok())
        .unwrap_or(OutputFormat::Table)
}

/// Trims trailing whitespace from each line in a multi-line string.
///
/// Useful for cleaning up table output before printing. Preserves newlines but removes spaces/tabs at line ends.
///
/// # Arguments
///
/// * `s` - Input string with potential trailing whitespace, e.g., "line1  \nline2   ".
///
/// # Returns
///
/// `String` - Cleaned string with trimmed lines, e.g., "line1\nline2".
///
/// # Examples
///
/// ```
/// # use keep::modes::common::trim_lines_end;
/// let cleaned = trim_lines_end("line1  \nline2   ");
/// assert_eq!(cleaned, "line1\nline2");
/// ```
pub fn trim_lines_end(s: &str) -> String {
    s.lines()
        .map(|line| line.trim_end())
        .collect::<Vec<&str>>()
        .join("\n")
}

/// Creates a new table with styling based on terminal detection.
///
/// Loads appropriate preset (UTF8 or ASCII) if styling is enabled.
///
/// # Arguments
///
/// * `use_styling` - If true, apply visual styling.
///
/// # Returns
///
/// `Table` - Configured table instance.
///
/// # Examples
///
/// ```
/// # use keep::modes::common::create_table;
/// let mut table = create_table(true);
/// table.add_row(vec!["Header1", "Header2"]);
/// ```
pub fn create_table(use_styling: bool) -> Table {
    let mut table = Table::new();
    table.set_content_arrangement(ContentArrangement::Dynamic);

    if use_styling {
        if std::io::stdout().is_terminal() {
            table
                .load_preset(comfy_table::presets::UTF8_FULL)
                .apply_modifier(comfy_table::modifiers::UTF8_SOLID_INNER_BORDERS);
        } else {
            table.load_preset(comfy_table::presets::ASCII_FULL);
        }
    } else {
        table.load_preset(comfy_table::presets::NOTHING);
    }

    if !std::io::stdout().is_terminal() {
        table.force_no_tty();
    }
    table
}

/// Creates a table configured from application table settings.
///
/// Applies style presets, modifiers, content arrangement, and truncation indicators.
///
/// # Arguments
///
/// * `table_config` - Table configuration from settings.
///
/// # Returns
///
/// `Table` - Fully configured table.
///
/// # Examples
///
/// ```
/// # use keep::modes::common::create_table_with_config;
/// # use keep::config::TableConfig;
/// let config = TableConfig::default();
/// let table = create_table_with_config(&config);
/// ```
pub fn create_table_with_config(table_config: &crate::config::TableConfig) -> Table {
    let mut table = Table::new();

    // Set content arrangement
    match table_config.content_arrangement {
        crate::config::ContentArrangement::Dynamic => {
            table.set_content_arrangement(comfy_table::ContentArrangement::Dynamic)
        }
        crate::config::ContentArrangement::DynamicFullWidth => {
            table.set_content_arrangement(comfy_table::ContentArrangement::DynamicFullWidth)
        }
        crate::config::ContentArrangement::Disabled => {
            table.set_content_arrangement(comfy_table::ContentArrangement::Disabled)
        }
    };

    // Set style preset
    match &table_config.style {
        crate::config::TableStyle::Ascii => {
            table.load_preset(comfy_table::presets::ASCII_FULL);
        }
        crate::config::TableStyle::Utf8 => {
            table.load_preset(comfy_table::presets::UTF8_FULL);
        }
        crate::config::TableStyle::Utf8Full => {
            table.load_preset(comfy_table::presets::UTF8_FULL);
        }
        crate::config::TableStyle::Nothing => {
            table.load_preset(comfy_table::presets::NOTHING);
        }
        crate::config::TableStyle::Custom(preset) => {
            // For custom presets, we'd need to parse the string
            // This is a placeholder for custom preset handling
            if preset == "ASCII_FULL" {
                table.load_preset(comfy_table::presets::ASCII_FULL);
            } else if preset == "UTF8_FULL" {
                table.load_preset(comfy_table::presets::UTF8_FULL);
            } else if preset == "NOTHING" {
                table.load_preset(comfy_table::presets::NOTHING);
            }
            // Add more presets as needed
        }
    };

    // Apply modifiers
    for modifier in &table_config.modifiers {
        match modifier.as_str() {
            "UTF8_SOLID_INNER_BORDERS" => {
                table.apply_modifier(comfy_table::modifiers::UTF8_SOLID_INNER_BORDERS);
            }
            "UTF8_ROUND_CORNERS" => {
                table.apply_modifier(comfy_table::modifiers::UTF8_ROUND_CORNERS);
            }
            _ => {} // Ignore unknown modifiers
        }
    }

    // Set truncation indicator if specified
    if !table_config.truncation_indicator.is_empty() {
        table.set_truncation_indicator(&table_config.truncation_indicator);
    }

    if !std::io::stdout().is_terminal() {
        table.force_no_tty();
    }

    table
}