use std::path::PathBuf;
use std::str::FromStr;

use clap::*;

/**
 * Main struct for command-line arguments.
 */
#[derive(Parser, Debug, Clone)]
#[command(author, version, about, long_about = None)]
pub struct Args {
    #[command(flatten)]
    pub mode: ModeArgs,
    #[command(flatten)]
    pub item: ItemArgs,
    #[command(flatten)]
    pub options: OptionsArgs,

    #[arg(help("A list of either item IDs or tags"))]
    #[arg(value_parser = clap::value_parser!(NumberOrString))]
    pub ids_or_tags: Vec<NumberOrString>,
}

/**
 * Struct for mode-specific arguments.
 */
#[derive(Parser, Debug, Clone)]
pub struct ModeArgs {
    #[arg(group("mode"), help_heading("Mode Options"), short, long, conflicts_with_all(["get", "diff", "list", "delete", "info", "status"]))]
    #[arg(help("Save an item using any tags or metadata provided"))]
    pub save: bool,

    #[arg(group("mode"), help_heading("Mode Options"), short, long, conflicts_with_all(["save", "diff", "list", "delete", "info", "status"]))]
    #[arg(help(
        "Get an item either by it's ID or by a combination of matching tags and metatdata"
    ))]
    pub get: bool,

    #[arg(group("mode"), help_heading("Mode Options"), long, conflicts_with_all(["save", "get", "list", "delete", "info", "status"]))]
    #[arg(help("Show a diff between two items by ID"))]
    pub diff: bool,

    #[arg(group("mode"), help_heading("Mode Options"), short, long, conflicts_with_all(["save", "get", "diff", "delete", "info", "status"]))]
    #[arg(help("List items, filtering on tags or metadata if given"))]
    pub list: bool,


    #[arg(group("mode"), help_heading("Mode Options"), short, long, conflicts_with_all(["save", "get", "diff", "list", "info", "status"]), requires("ids_or_tags"))]
    #[arg(help("Delete items either by ID or by matching tags"))]
    pub delete: bool,

    #[arg(group("mode"), help_heading("Mode Options"), short, long, conflicts_with_all(["save", "get", "diff", "list", "delete", "status"]), requires("ids_or_tags"))]
    #[arg(help(
        "Get an item either by it's ID or by a combination of matching tags and metatdata"
    ))]
    pub info: bool,

    #[arg(group("mode"), help_heading("Mode Options"), short('S'), long, conflicts_with_all(["save", "get", "diff", "list", "delete", "info", "server"]))]
    #[arg(help("Show status of directories and supported compression algorithms"))]
    pub status: bool,

    #[arg(group("mode"), help_heading("Mode Options"), long, conflicts_with_all(["save", "get", "diff", "list", "delete", "info", "status"]))]
    #[arg(help("Start REST HTTP server"))]
    pub server: bool,

    #[arg(help_heading("Server Options"), long, env("KEEP_SERVER_ADDRESS"))]
    #[arg(help("Server address to bind to"))]
    pub server_address: Option<String>,

    #[arg(help_heading("Server Options"), long, env("KEEP_SERVER_PORT"))]
    #[arg(help("Server port to bind to"))]
    pub server_port: Option<u16>,
}

/**
 * Struct for item-specific arguments.
 */
#[derive(Parser, Debug, Clone)]
pub struct ItemArgs {
    #[arg(help_heading("Item Options"), short, long, env("KEEP_COMPRESSION"))]
    #[arg(help("Compression algorithm to use when saving items"))]
    pub compression: Option<String>,

    #[arg(help_heading("Item Options"), short('M'), long, env("KEEP_META_PLUGINS"))]
    #[arg(help("Meta plugins to use when saving items"))]
    pub meta_plugins: Vec<String>,
}


/**
 * Struct for general options.
 */
#[derive(Parser, Debug, Default, Clone)]
pub struct OptionsArgs {
    #[arg(long, env("KEEP_CONFIG"))]
    #[arg(help("Specify the configuration file to use"))]
    pub config: Option<PathBuf>,

    #[arg(long, env("KEEP_DIR"))]
    #[arg(help("Specify the directory to use for storage"))]
    pub dir: Option<PathBuf>,

    #[arg(
        long,
        env("KEEP_LIST_FORMAT"),
        default_value("id,time,size,tags,meta:hostname")
    )]
    #[arg(help("A comma separated list of columns to display with --list"))]
    pub list_format: String,

    #[arg(short('H'), long)]
    #[arg(help("Display file sizes with units"))]
    pub human_readable: bool,

    #[arg(short, long, action = clap::ArgAction::Count, conflicts_with("quiet"))]
    #[arg(help("Increase message verbosity, can be given more than once"))]
    pub(crate) verbose: u8,

    #[arg(short, long)]
    #[arg(help("Do not show any messages"))]
    pub quiet: bool,

    #[arg(long, value_enum, default_value("table"))]
    #[arg(help("Output format (only works with --info, --status, --list)"))]
    pub output_format: Option<String>,

    #[arg(long, env("KEEP_SERVER_PASSWORD"))]
    #[arg(help("Password for server authentication (requires --server)"))]
    pub server_password: Option<String>,

    #[arg(long, env("KEEP_SERVER_PASSWORD_HASH"))]
    #[arg(help("Password hash for server authentication (requires --server)"))]
    pub server_password_hash: Option<String>,

    #[arg(long, help("Force output even when binary data would be sent to a TTY"))]
    pub force: bool,
}

/**
 * Enum for representing either a number or a string.
 */
#[derive(Debug, Clone)]
pub enum NumberOrString {
    Number(i64),
    Str(String),
}

impl FromStr for NumberOrString {
    type Err = Error;
    fn from_str(s: &str) -> Result<Self, Self::Err> {
        Ok(s.parse::<i64>()
            .map(NumberOrString::Number)
            .unwrap_or_else(|_| NumberOrString::Str(s.to_string())))
    }
}