use anyhow::Result;
use dialoguer::{Input, Select, theme::ColorfulTheme};
use iroh_tickets::endpoint::EndpointTicket;
use std::str::FromStr;

use crate::cli::{Cli, Quality};
use crate::common::{bandwidth, config};
use crate::{host, viewer};

pub async fn run(cli: Cli) -> Result<()> {
    print_welcome();

    let theme = ColorfulTheme::default();
    let choice = Select::with_theme(&theme)
        .with_prompt("What do you want to do?")
        .items([
            "Host (share my screen)",
            "View (watch someone else's screen)",
        ])
        .default(0)
        .interact()?;

    match choice {
        0 => {
            preflight_if_needed(&theme).await;
            let mut cli = cli;
            if cli.app.is_none() {
                cli.app = pick_app(&theme)?;
            }
            if cli.quality.is_none() {
                cli.quality = Some(pick_quality(&theme)?);
            }
            host::run(cli.into_host_opts(true)).await
        }
        _ => {
            let ticket = prompt_ticket(&theme)?;
            viewer::run(ticket, cli.into_viewer_opts(true)).await
        }
    }
}

/// Picker for the per-app audio capture choice. Lists apps currently
/// producing audio (deduped by `application.name`); user picks one or
/// the "all system audio" default. Bypassed when `--app NAME` was given
/// on the CLI.
fn pick_app(theme: &ColorfulTheme) -> Result<Option<String>> {
    let apps = match host::audio::list_playing_apps() {
        Ok(a) => a,
        Err(e) => {
            tracing::warn!("could not enumerate playing apps: {e:#}");
            return Ok(None);
        }
    };

    eprintln!();
    eprintln!("Audio capture");
    eprintln!("─────────────");
    if apps.is_empty() {
        eprintln!("No other apps are currently producing audio.");
        eprintln!("Start your game / music / call first if you want to pick it specifically.");
    }
    eprintln!();

    let mut items = vec!["Capture all system audio (default)".to_string()];
    for app in &apps {
        items.push(if app.stream_count == 1 {
            app.name.clone()
        } else {
            format!("{} ({} streams)", app.name, app.stream_count)
        });
    }

    let choice = Select::with_theme(theme)
        .with_prompt("What audio should the viewer hear?")
        .items(&items)
        .default(0)
        .interact()?;

    if choice == 0 {
        Ok(None)
    } else {
        Ok(Some(apps[choice - 1].name.clone()))
    }
}

/// Picker for the encode quality preset. Mirrors [`pick_app`]; bypassed when
/// `--quality` was given on the CLI. Quality is host-global (the same stream
/// fans out to every viewer), so this is the one choice that sets it for all.
fn pick_quality(theme: &ColorfulTheme) -> Result<Quality> {
    eprintln!();
    eprintln!("Quality");
    eprintln!("───────");
    eprintln!("Lower presets trade resolution + bitrate for less upload usage.");
    eprintln!("The same quality is sent to every viewer.");
    eprintln!();

    // Order mirrors the labels below; index maps back to a Quality.
    let choices = [
        Quality::Auto,
        Quality::Source,
        Quality::High,
        Quality::Medium,
        Quality::Low,
    ];
    let items = [
        "Auto — pick from my measured upstream (recommended)",
        "Source — native resolution, 6000 kbps",
        "High — up to 1080p, 4000 kbps",
        "Medium — up to 720p, 2500 kbps",
        "Low — up to 480p, 1000 kbps",
    ];

    let choice = Select::with_theme(theme)
        .with_prompt("What quality should the viewer(s) get?")
        .items(items)
        .default(0)
        .interact()?;

    Ok(choices[choice])
}

/// `pixelpass --reconfigure` entry point: unconditionally re-run the
/// bandwidth pre-flight test, save the result, and return. Used to
/// refresh a stale measurement (e.g. user moved house, changed ISP).
pub async fn run_reconfigure() -> Result<()> {
    eprintln!();
    eprintln!("Re-running bandwidth pre-flight test…");
    let mut cfg = config::load().unwrap_or_default();
    run_bandwidth_test(&mut cfg).await;
    Ok(())
}

/// First-run pre-flight gate. Called once, when the user picks "Host" in
/// the interactive menu. Behavior by saved status:
/// - Unmeasured (first ever launch): explain + offer Run / Skip
/// - Failed (previous attempt errored): offer Retry / give-up-and-skip
/// - Measured or Skipped: silent — never re-prompts
async fn preflight_if_needed(theme: &ColorfulTheme) {
    let mut cfg = config::load().unwrap_or_default();
    match cfg.bandwidth.status {
        config::BandwidthStatus::Measured | config::BandwidthStatus::Skipped => (),
        config::BandwidthStatus::Unmeasured => {
            eprintln!();
            eprintln!("First-time setup");
            eprintln!("────────────────");
            eprintln!("PixelPass can measure your upload speed to recommend a safe");
            eprintln!("default for how many viewers your connection can handle.");
            eprintln!("The test takes about 5 seconds and uploads ~5 MB to");
            eprintln!("Cloudflare's open speed-test endpoint.");
            eprintln!();
            eprintln!("If you skip, a conservative default (2 viewers) is used.");
            eprintln!("You can run the test later with `pixelpass --reconfigure`.");
            eprintln!();

            let Ok(choice) = Select::with_theme(theme)
                .with_prompt("What would you like to do?")
                .items([
                    "Run the bandwidth test (recommended)",
                    "Skip — use the conservative default",
                ])
                .default(0)
                .interact()
            else {
                return;
            };

            if choice == 1 {
                cfg.bandwidth = config::BandwidthEntry {
                    status: config::BandwidthStatus::Skipped,
                    upstream_mbps: None,
                    measured_at: None,
                };
                let _ = config::save(&cfg);
                eprintln!("Pre-flight skipped.");
                return;
            }
            run_bandwidth_test(&mut cfg).await;
        }
        config::BandwidthStatus::Failed => {
            eprintln!();
            let Ok(choice) = Select::with_theme(theme)
                .with_prompt("Last bandwidth test failed. Try again?")
                .items(["Yes — retry now", "No — use the conservative default"])
                .default(0)
                .interact()
            else {
                return;
            };

            if choice == 1 {
                cfg.bandwidth = config::BandwidthEntry {
                    status: config::BandwidthStatus::Skipped,
                    upstream_mbps: None,
                    measured_at: None,
                };
                let _ = config::save(&cfg);
                eprintln!("OK — using the conservative default.");
                return;
            }
            run_bandwidth_test(&mut cfg).await;
        }
    }
}

async fn run_bandwidth_test(cfg: &mut config::Config) {
    eprintln!();
    eprintln!("Measuring upstream…");

    let result = tokio::task::spawn_blocking(bandwidth::measure_upstream_blocking).await;
    let measurement = match result {
        Ok(Ok(m)) => m,
        Ok(Err(e)) => {
            eprintln!("Test failed: {e:#}");
            eprintln!("Marking as failed — you'll be asked again on next launch.");
            cfg.bandwidth = config::BandwidthEntry {
                status: config::BandwidthStatus::Failed,
                upstream_mbps: None,
                measured_at: None,
            };
            let _ = config::save(cfg);
            return;
        }
        Err(join_err) => {
            eprintln!("Test task panicked: {join_err}");
            cfg.bandwidth = config::BandwidthEntry {
                status: config::BandwidthStatus::Failed,
                upstream_mbps: None,
                measured_at: None,
            };
            let _ = config::save(cfg);
            return;
        }
    };

    eprintln!(
        "Measured {:.2} Mbps up (safe estimate {:.2} Mbps, took {:.1}s).",
        measurement.raw_mbps,
        measurement.safe_mbps,
        measurement.elapsed.as_secs_f64()
    );
    cfg.bandwidth = config::BandwidthEntry {
        status: config::BandwidthStatus::Measured,
        upstream_mbps: Some(measurement.safe_mbps),
        measured_at: Some(chrono::Utc::now()),
    };
    if let Err(e) = config::save(cfg) {
        eprintln!("Warning: failed to save result: {e:#}");
    }
}

fn print_welcome() {
    eprintln!();
    eprintln!("Welcome to PixelPass.");
    eprintln!();
}

fn prompt_ticket(theme: &ColorfulTheme) -> Result<EndpointTicket> {
    loop {
        let raw: String = Input::with_theme(theme)
            .with_prompt("Paste the share code you received")
            .interact_text()?;
        match EndpointTicket::from_str(raw.trim()) {
            Ok(t) => return Ok(t),
            Err(_) => eprintln!("That doesn't look like a share code. Try again."),
        }
    }
}

/// Player options the interactive viewer can launch.
#[derive(Clone, Copy)]
pub enum Player {
    Mpv,
    Vlc,
}

impl Player {
    pub fn spawn(self, url: &str) -> std::io::Result<()> {
        match self {
            Player::Mpv => crate::common::process::spawn_detached(
                "mpv",
                &[
                    // No `--untimed`: it ignores audio timestamps and drifts a
                    // shared video out of sync. Pacing to audio keeps A/V synced.
                    // Also leave hwdec at the `low-latency` default (software
                    // decode): forcing `--hwdec=auto` froze some viewers on
                    // frame 1 while audio kept playing.
                    "--profile=low-latency",
                    "--audio-buffer=0.2",
                    "--demuxer-max-bytes=2M",
                    "--demuxer-readahead-secs=0.5",
                    url,
                ],
            ),
            Player::Vlc => {
                warn_if_vlc_plugins_missing();
                crate::common::process::spawn_detached(
                    "vlc",
                    &["--network-caching=200", "--live-caching=200", url],
                )
            }
        }
    }
}

// On Arch-family distros, the base `vlc` package omits two plugins
// pixelpass needs: the MPEG-TS demuxer (`vlc-plugin-dvb`) and the
// libavcodec-based H.264 decoder (`vlc-plugin-ffmpeg`). Missing either
// produces a confusing error chain — warn at launch.
fn warn_if_vlc_plugins_missing() {
    const REQUIRED: &[(&str, &str)] = &[
        (
            "/usr/lib/vlc/plugins/demux/libts_plugin.so",
            "vlc-plugin-dvb",
        ),
        (
            "/usr/lib/vlc/plugins/codec/libavcodec_plugin.so",
            "vlc-plugin-ffmpeg",
        ),
    ];
    let missing: Vec<&(&str, &str)> = REQUIRED
        .iter()
        .filter(|(p, _)| !std::path::Path::new(p).exists())
        .collect();
    if missing.is_empty() {
        return;
    }
    eprintln!();
    eprintln!("Warning: VLC is missing plugins pixelpass needs:");
    for (path, pkg) in &missing {
        eprintln!("  - {path} (install `{pkg}`)");
    }
    eprintln!("On Arch / CachyOS / EndeavourOS: `sudo pacman -S {}`.", {
        let names: Vec<&str> = missing.iter().map(|(_, p)| *p).collect();
        names.join(" ")
    });
    eprintln!("mpv is unaffected.");
    eprintln!();
}

pub fn prompt_player() -> Result<Player> {
    let theme = ColorfulTheme::default();
    let choice = Select::with_theme(&theme)
        .with_prompt("Connected. Pick a player to launch")
        .items(["mpv", "VLC"])
        .default(0)
        .interact()?;
    Ok(if choice == 0 {
        Player::Mpv
    } else {
        Player::Vlc
    })
}