use crate::config::ThemeColors;
use crate::theme::Theme;

pub const RESET: &str = "\x1b[0m";
pub const BOLD: &str = "\x1b[1m";
pub const DIM: &str = "\x1b[2m";
pub const RED: &str = "\x1b[31m";
pub const GREEN: &str = "\x1b[32m";
pub const YELLOW: &str = "\x1b[33m";
pub const BLUE: &str = "\x1b[34m";
pub const MAGENTA: &str = "\x1b[35m";
pub const CYAN: &str = "\x1b[36m";
pub const WHITE: &str = "\x1b[37m";

/// Resolve a color name to ANSI escape sequence(s).
pub fn resolve_color(name: &str, theme: Theme, palette: &ThemeColors) -> String {
    if let Some(key) = name.strip_prefix("p:") {
        let map = match theme {
            Theme::Dark => &palette.dark,
            Theme::Light => &palette.light,
        };
        if let Some(resolved) = map.get(key) {
            return resolve_color(resolved, theme, palette);
        }
        return RESET.to_string();
    }

    let mut result = String::new();
    for part in name.split_whitespace() {
        result.push_str(match part {
            "red" => RED,
            "green" => GREEN,
            "yellow" => YELLOW,
            "blue" => BLUE,
            "magenta" => MAGENTA,
            "cyan" => CYAN,
            "white" => WHITE,
            "dim" => DIM,
            "bold" => BOLD,
            _ => "",
        });
    }

    if result.is_empty() {
        RESET.to_string()
    } else {
        result
    }
}

/// Determine whether color output should be used.
pub fn should_use_color(cli_color: Option<&str>, config_color: &crate::config::ColorMode) -> bool {
    if std::env::var("NO_COLOR").is_ok() {
        return false;
    }

    if let Some(flag) = cli_color {
        return match flag {
            "always" => true,
            "never" => false,
            _ => atty_stdout(),
        };
    }

    match config_color {
        crate::config::ColorMode::Always => true,
        crate::config::ColorMode::Never => false,
        crate::config::ColorMode::Auto => {
            atty_stdout() && std::env::var("TERM").map_or(true, |t| t != "dumb")
        }
    }
}

fn atty_stdout() -> bool {
    unsafe { libc::isatty(libc::STDOUT_FILENO) != 0 }
}