// bibiman - a TUI for managing BibLaTeX databases
// Copyright (C) 2024  lukeflo
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <https://www.gnu.org/licenses/>.
/////

use dirs::{config_dir, home_dir};
use lexopt::prelude::*;
use owo_colors::OwoColorize;
use owo_colors::colors::css::LightGreen;
use owo_colors::colors::*;
use std::env;
use std::path::PathBuf;
use walkdir::WalkDir;

use crate::app;
use crate::config::BibiConfig;

// struct for CLIArgs
#[derive(Debug, Default, Clone)]
pub struct CLIArgs {
    pub pos_args: Vec<PathBuf>,
    pub cfg_path: Option<PathBuf>,
    pub light_theme: bool,
    pub pdf_path: Option<PathBuf>,
}

impl CLIArgs {
    pub fn parse_args() -> color_eyre::Result<(CLIArgs, BibiConfig)> {
        let mut args = CLIArgs::default();
        let mut parser = lexopt::Parser::from_env();
        let mut subcommand = None;

        // Default config
        args.cfg_path = if config_dir().is_some() {
            Some(config_dir().unwrap().join("bibiman/bibiman.toml"))
        } else if home_dir().is_some() {
            Some(home_dir().unwrap().join(".config/bibiman/bibiman.toml"))
        } else {
            None
        };

        // if parser
        //     .raw_args()
        //     .is_ok_and(|mut arg| arg.next_if(|a| a == "format-citekeys").is_some())
        // {
        //     todo!("Format citekeys options");
        // }

        while let Some(arg) = parser.next()? {
            match arg {
                Short('h') | Long("help") => {
                    println!("{}", help_func());
                    std::process::exit(0);
                }
                Short('v') | Long("version") => {
                    println!("{}", version_func());
                    std::process::exit(0);
                }
                Short('c') | Long("config-file") => args.cfg_path = Some(parser.value()?.parse()?),
                Long("light-terminal") => args.light_theme = true,
                Long("pdf-path") => {
                    args.pdf_path = Some(parser.value()?.parse()?);
                }
                Value(pos_arg) => {
                    if args.pos_args.is_empty() {
                        let value = pos_arg
                            .into_string()
                            .unwrap_or_else(|os| os.to_string_lossy().to_string());
                        match value.as_str() {
                            "format-citekeys" => {
                                subcommand = Some(value);
                                break;
                            }
                            _ => {
                                args.pos_args.push(value.into());
                            }
                        }
                    } else {
                        args.pos_args.push(pos_arg.into());
                    }
                }
                _ => return Err(arg.unexpected().into()),
            }
        }

        if args
            .cfg_path
            .as_ref()
            .is_some_and(|f| f.try_exists().is_err() || !f.is_file())
        {
            BibiConfig::create_default_config(&args);
        }

        let mut cfg = if args.cfg_path.is_some() {
            BibiConfig::parse_config(&args)?
        } else {
            BibiConfig::new(&args)
        };

        if let Some(cmd) = subcommand {
            match cmd.as_str() {
                "format-citekeys" => todo!("write citekey formatting"),
                _ => {}
            }
        }

        cfg.cli_overwrite(&args);

        Ok((args, cfg))
    }
}

/// This function maps a vector containing paths to another vector containing paths.
/// But it will walk all entries of the first vec which are directories
/// and put only valid file paths with `.bib` ending to the resulting vec.
pub fn parse_files(args: Vec<PathBuf>) -> Vec<PathBuf> {
    let mut files: Vec<PathBuf> = Vec::new();
    // If pos arg is file, just push it to path vec
    for i in args {
        // Expand tilde to /home/user
        let i = if i.starts_with("~") {
            app::expand_home(&i)
        } else {
            i
        };
        if i.is_file() {
            files.push(i);
        // If pos arg is dir, walk dir and collect bibfiles
        } else if i.is_dir() {
            for file in WalkDir::new(i) {
                let f = file.unwrap().into_path();
                if f.is_file()
                    && f.extension().is_some()
                    && f.extension().unwrap_or_default() == "bib"
                {
                    files.push(f)
                }
            }
        } else {
            println!(
                "{}\n{}",
                "The positional argument is neither a valid file, nor a directory:"
                    .red()
                    .bold(),
                i.as_os_str().to_string_lossy().bright_red().italic()
            );
            println!();
            println!("{}", help_func());
            std::process::exit(1)
        }
    }
    files
}

pub fn help_func() -> String {
    let help = vec![
        format!(
            "{} {}\n",
            env!("CARGO_PKG_NAME").fg::<Green>().bold(),
            env!("CARGO_PKG_VERSION").fg::<LightGreen>(),
        ),
        format!(
            "{}:\n\t{} [Flags] [files/dirs]\n",
            "USAGE".bold(),
            "bibiman".bold()
        ),
        format!(
            "{}:\n\t{}\t\tPath to {} file",
            "POSITIONAL ARGUMENTS".bold(),
            "<file>".fg::<BrightMagenta>().bold(),
            ".bib".fg::<BrightBlack>().bold()
        ),
        format!(
            "\t{}\tPath to directory containing {} files",
            "<directory>".fg::<BrightBlue>().bold(),
            ".bib".fg::<BrightBlack>().bold()
        ),
        format!("\n\t{}", "Both can be passed multiple times".italic()),
        format!("\n{}:", "FLAGS".bold()),
        format!("\t{}", "-h, --help".bold().fg::<BrightCyan>()),
        format!("\t\t{}", "Show this help and exit"),
        format!("\t{}", "-v, --version".bold().fg::<BrightCyan>()),
        format!("\t\t{}", "Show the version and exit"),
        format!("\t{}", "--light-terminal".bold().fg::<BrightCyan>()),
        format!(
            "\t\t{}",
            "Enable default colors for light terminal background"
        ),
        format!(
            "\t{}{}",
            "-c, --config-file=".bold().fg::<BrightCyan>(),
            "<value>".bold().italic().fg::<BrightCyan>()
        ),
        format!("\t\t{}", "Path to config file used for current session."),
        format!("\t\t{}", "Takes precedence over standard config file."),
        format!(
            "\t{}{}",
            "--pdf-path=".bold().fg::<BrightCyan>(),
            "<value>".bold().italic().fg::<BrightCyan>()
        ),
        format!("\t\t{}", "Path to directory containing PDF files."),
        format!(
            "\t\t{}",
            "If the pdf files basename matches an entrys citekey,"
        ),
        format!(
            "\t\t{}",
            "its attached as connected PDF file for the current session."
        ),
        format!("\t\t{}", "Does not edit the bibfile itself!"),
    ];
    let help = help.join("\n");
    help
}

pub fn version_func() -> String {
    let version: Vec<String> = vec![
        format!(
            "{} {}",
            env!("CARGO_PKG_NAME").fg::<Green>().bold(),
            env!("CARGO_PKG_VERSION").fg::<LightGreen>()
        ),
        format!("{}", env!("CARGO_PKG_AUTHORS").bold()),
        format!("{}", env!("CARGO_PKG_LICENSE")),
        format!("\n"),
        format!(
            "{} {}",
            "Target Triple:".bold(),
            env!("TARGET").fg::<BrightRed>()
        ),
    ];
    let version = version.join("\n");
    version
}