/*
 * This file is a part of RSPlayer
 * Licensed under the GPL-3.0 License
 * Copyright (C) 2026 Salmonik @ salmonik@tuta.io
 * https://codeberg.org/salmonik/RSPlayer
*/

use crate::config::Config;
use crate::database::Database;
use clap::{Command, CommandFactory, Parser, Subcommand};
use clap_complete::{Shell, generate};
use std::path::PathBuf;
use std::time::Duration;

#[derive(Parser)]
#[command(name = "rsp", infer_long_args = true)]
#[command(about = "Rust music player daemon", long_about = None)]
pub struct Cli {
    #[command(subcommand)]
    pub command: Commands,
}

#[derive(Subcommand)]
pub enum Commands {
    /// Start the daemon
    StartDaemon,
    /// Stop the daemon
    StopDaemon,
    /// Restart the daemon (kill existing and start new)
    Restart,
    /// Play a track, album, or artist
    Play {
        /// Add after current track and skip to it
        #[arg(short = 'i', long = "now")]
        now: bool,
        /// Add to queue after current track (don't skip)
        #[arg(short = 'n', long = "next")]
        next: bool,
        /// Queue the entire album containing this track (start at this track)
        #[arg(short = 'a', long = "album")]
        album: bool,
        #[arg(value_name = "QUERY")]
        query: Option<String>,
    },
    /// Pause playback
    Pause,
    /// Resume playback
    Resume,
    /// Toggle play/pause
    Toggle,
    /// Stop playback
    Stop,
    /// Skip to next track
    Next,
    /// Skip to previous track
    Previous,
    /// Set volume (0-100), or +N/-N for relative change
    Volume {
        #[arg(value_name = "LEVEL")]
        level: Option<String>,
    },
    /// Shuffle mode
    Shuffle {
        #[arg(value_name = "MODE")]
        mode: Option<String>,
    },
    /// Show the queue
    Queue,
    /// Show player status
    Status,
    /// Seek within the current track
    Seek {
        /// Position: `90`, `1:30`, `1:02:03`, or a relative offset `+15` / `-30`;
        /// without one, the current position is printed
        #[arg(value_name = "POSITION", allow_hyphen_values = true)]
        position: Option<String>,
    },
    /// Scan music paths to populate database
    Scan {
        #[arg(long)]
        force: bool,
        #[arg(long, value_name = "PATHS")]
        paths: Option<Vec<PathBuf>>,
    },
    /// Settings management
    Settings {
        #[command(subcommand)]
        command: SettingsCommands,
    },
    #[clap(hide = true)]
    /// Generate shell completions (developer only)
    Completions {
        /// Shell to generate (bash, zsh, fish, elvish, powershell)
        /// If not specified, generates all completion files
        #[arg(value_name = "SHELL")]
        shell: Option<String>,
    },
    #[clap(hide = true)]
    /// Complete artists, albums, or tracks from database
    DbComplete {
        /// Query string (e.g. \"J\", \"Artist/\", \"Artist/Album/\")
        #[arg(value_name = "QUERY")]
        query: String,
    },
    /// display lyrics
    Lyrics,
}

#[derive(Subcommand)]
pub enum SettingsCommands {
    /// Get a setting value
    Get {
        #[arg(value_name = "KEY")]
        key: String,
    },
    /// Set a setting value
    Set {
        #[arg(value_name = "KEY")]
        key: String,
        #[arg(value_name = "VALUE")]
        value: String,
    },
    /// List all settings
    List,
    /// Unset a setting
    Unset {
        #[arg(value_name = "KEY")]
        key: String,
    },
    /// Reload config from disk (re-reads config file, re-validates scrobbling tokens)
    Reload,
}

impl Cli {
    pub fn run(&self) -> Result<(), Box<dyn std::error::Error>> {
        match &self.command {
            Commands::StartDaemon => {
                crate::daemon::start_daemon()?;
            }
            Commands::StopDaemon => {
                crate::daemon::stop_daemon()?;
            }
            Commands::Restart => {
                crate::daemon::restart_daemon()?;
            }
            Commands::Play {
                now,
                next,
                album,
                query,
                ..
            } => {
                if let Some(q) = query {
                    let pos = if *now {
                        "now"
                    } else if *next {
                        "next"
                    } else {
                        "last"
                    };
                    if *album {
                        crate::daemon::send_command(format!("play-album {} {}", pos, q))?;
                    } else {
                        crate::daemon::send_command(format!("play {} {}", pos, q))?;
                    }
                } else {
                    crate::daemon::send_command("play last".to_string())?;
                }
            }
            Commands::Pause => {
                crate::daemon::send_command("pause".to_string())?;
            }
            Commands::Resume => {
                crate::daemon::send_command("resume".to_string())?;
            }
            Commands::Toggle => {
                crate::daemon::send_command("toggle".to_string())?;
            }
            Commands::Stop => {
                crate::daemon::send_command("stop".to_string())?;
            }
            Commands::Next => {
                crate::daemon::send_command("next".to_string())?;
            }
            Commands::Previous => {
                crate::daemon::send_command("previous".to_string())?;
            }
            Commands::Volume { level } => {
                if let Some(l) = level {
                    crate::daemon::send_command(format!("volume {}", l))?;
                } else {
                    crate::daemon::send_command("volume".to_string())?;
                }
            }
            Commands::Shuffle { mode } => {
                if let Some(m) = mode {
                    crate::daemon::send_command(format!("shuffle {}", m))?;
                } else {
                    crate::daemon::send_command("shuffle".to_string())?;
                }
            }
            Commands::Queue => {
                crate::daemon::send_command("queue".to_string())?;
            }
            Commands::Status => {
                crate::daemon::send_command("status".to_string())?;
            }
            Commands::Seek { position } => match position {
                Some(p) => crate::daemon::send_command(format!("seek {}", p))?,
                None => crate::daemon::send_command("seek".to_string())?,
            },
            Commands::Scan { force, paths } => {
                let config = Config::load()?;
                let db = Database::open(&config)?;
                if let Some(custom_paths) = paths {
                    db.scan_paths(custom_paths, *force)?;
                } else {
                    db.scan_paths(&config.music_paths, *force)?;
                }
                println!("Scan complete");
            }
            Commands::Settings { command } => {
                let mut config = Config::load()?;
                match command {
                    SettingsCommands::Get { key } => {
                        println!("{}", config.get(key)?);
                    }
                    SettingsCommands::Set { key, value } => {
                        config.set(key, value)?;
                        config.save()?;
                        if key == "listenbrainz_token" {
                            let _ = crate::daemon::send_command("validate".to_string());
                        }
                    }
                    SettingsCommands::List => {
                        config.list();
                    }
                    SettingsCommands::Unset { key } => {
                        config.unset(key)?;
                        config.save()?;
                    }
                    SettingsCommands::Reload => {
                        let _ = crate::daemon::send_command("reload".to_string());
                    }
                }
            }
            Commands::DbComplete { query } => {
                // Unescape shell escapes in the input query
                let query = {
                    let mut unescaped = String::with_capacity(query.len());
                    let mut chars = query.chars();
                    while let Some(c) = chars.next() {
                        if c == '\\' {
                            if let Some(next) = chars.next() {
                                unescaped.push(next);
                            }
                        } else {
                            unescaped.push(c);
                        }
                    }
                    unescaped
                };

                // Empty query: synchronously query the DB directly (no timeout thread)
                // and never fall back to a directory listing, which would be confusing.
                if query.is_empty() {
                    if let Ok(config) = Config::load()
                        && let Ok(db) = Database::open(&config)
                    {
                        let results = db.complete("").unwrap_or_default();
                        for r in &results {
                            println!("{r}");
                        }
                    }
                    return Ok(());
                }

                // If query looks like a filesystem path, skip DB entirely
                if looks_like_path(&query) {
                    for c in complete_path(&query) {
                        println!("{c}");
                    }
                    return Ok(());
                }

                // Try DB completion with a timeout; if nothing returned, fall back
                // to filesystem path completion (e.g. empty library, no match).
                let db_results = db_complete_with_timeout(&query, Duration::from_millis(100));

                if let Some(ref results) = db_results
                    && !results.is_empty()
                {
                    for r in results {
                        println!("{r}");
                    }
                    return Ok(());
                }

                // Fallback: filesystem path completion
                for c in complete_path(&query) {
                    println!("{c}");
                }
            }
            Commands::Completions { shell } => {
                let full = Cli::command();
                let subcommands: Vec<Command> = full
                    .get_subcommands()
                    .filter(|s| s.get_name() != "completions" && s.get_name() != "db-complete")
                    .cloned()
                    .collect();
                let cmd_name = full.get_name().to_string();
                let about = full.get_about().cloned();
                let mut cmd = Command::new(cmd_name).infer_long_args(true);
                if let Some(a) = about {
                    cmd = cmd.about(a);
                }
                for sc in subcommands {
                    cmd = cmd.subcommand(sc);
                }
                if let Some(s) = shell {
                    let shell = match s.as_str() {
                        "bash" => Shell::Bash,
                        "zsh" => Shell::Zsh,
                        "fish" => Shell::Fish,
                        "elvish" => Shell::Elvish,
                        "powershell" => Shell::PowerShell,
                        _ => {
                            eprintln!("Unknown shell: {s}");
                            return Ok(());
                        }
                    };
                    generate(shell, &mut cmd, "rsp", &mut std::io::stdout());
                } else {
                    std::fs::create_dir_all("completions/")?;
                    let shells = [
                        (Shell::Bash, "bash"),
                        (Shell::Zsh, "zsh"),
                        (Shell::Fish, "fish"),
                        (Shell::Elvish, "elvish"),
                        (Shell::PowerShell, "powershell"),
                    ];
                    for (shell, ext) in &shells {
                        let path = format!("completions/rsp.{ext}");
                        let mut file = std::fs::File::create(&path)?;
                        generate(*shell, &mut cmd, "rsp", &mut file);
                        println!("Generated {path}");
                    }
                }
            }
            Commands::Lyrics => {
                let _ = crate::daemon::send_command("lyrics".to_string());
            }
        }
        Ok(())
    }
}

/// Returns true if the query looks like a filesystem path.
fn looks_like_path(query: &str) -> bool {
    query.starts_with("./")
        || query.starts_with("../")
        || query.starts_with("~/")
        || query.starts_with('/')
}

/// List files/directories matching `query`, formatted as completion candidates.
///
/// Directories get a trailing `/` so the shell knows they can be further expanded.
fn complete_path(query: &str) -> Vec<String> {
    if query.is_empty() {
        return Vec::new();
    }

    // Split at the last '/' to separate directory and filename prefix
    let (dir_part, file_prefix) = match query.rfind('/') {
        Some(pos) => (&query[..=pos], &query[pos + 1..]),
        None => ("", query),
    };

    // Resolve the directory to read.  For ~/… we need the expanded path;
    // everything else works as-is from the CWD.
    let read_dir = if let Some(rest) = dir_part.strip_prefix("~/") {
        if let Some(home) = dirs::home_dir() {
            if rest.is_empty() {
                home
            } else {
                home.join(rest.trim_end_matches('/'))
            }
        } else {
            PathBuf::from(dir_part)
        }
    } else if dir_part.is_empty() {
        PathBuf::from(".")
    } else {
        PathBuf::from(dir_part)
    };

    let mut results: Vec<String> = Vec::new();
    if let Ok(entries) = std::fs::read_dir(&read_dir) {
        for entry in entries.flatten() {
            let name = entry.file_name();
            let name_str = name.to_string_lossy().to_string();

            // Skip hidden entries unless the query explicitly asks for them
            if name_str.starts_with('.') && !file_prefix.starts_with('.') {
                continue;
            }
            if name_str == "." || name_str == ".." {
                continue;
            }

            if !name_str.starts_with(file_prefix) {
                continue;
            }

            let is_dir = entry.file_type().map(|t| t.is_dir()).unwrap_or(false);
            if is_dir {
                results.push(format!("{dir_part}{name_str}/"));
            } else {
                results.push(format!("{dir_part}{name_str}"));
            }
        }
    }
    results.sort();
    results
}

/// Try the DB completion query in a separate thread with a timeout.
///
/// Opens its own database connection so the caller doesn't need to keep one
/// alive.  Returns `None` on timeout or when the DB can't be opened.
fn db_complete_with_timeout(query: &str, timeout: Duration) -> Option<Vec<String>> {
    let query = query.to_string();
    let (tx, rx) = std::sync::mpsc::channel();

    std::thread::spawn(move || {
        if let Ok(config) = Config::load()
            && let Ok(db) = Database::open(&config)
        {
            let results = db.complete(&query).unwrap_or_default();
            let _ = tx.send(results);
        }
    });

    rx.recv_timeout(timeout).ok()
}