#[cfg(any(not(coverage), test))]
use anyhow::{Context, Result, bail};
#[cfg(not(coverage))]
use serde::Serialize;
#[cfg(any(not(coverage), test))]
use std::path::PathBuf;

#[cfg(not(coverage))]
use lesavka_client::sync_probe::analyze::{
    SyncAnalysisOptions, SyncAnalysisReport, SyncAnalysisVerdict, SyncCalibrationRecommendation,
    analyze_capture,
};

#[cfg(not(coverage))]
#[derive(Serialize)]
struct SyncAnalyzeOutput<'a> {
    #[serde(flatten)]
    report: &'a SyncAnalysisReport,
    calibration: SyncCalibrationRecommendation,
    verdict: SyncAnalysisVerdict,
}

#[cfg(not(coverage))]
fn main() -> Result<()> {
    let args = parse_args(std::env::args().skip(1))?;
    let report = analyze_capture(&args.capture_path, &SyncAnalysisOptions::default())
        .with_context(|| format!("analyzing sync capture {}", args.capture_path.display()))?;
    let calibration = report.calibration_recommendation();
    let verdict = report.verdict();
    let human_report = format_human_report(&args.capture_path, &report, &calibration, &verdict);
    let output = SyncAnalyzeOutput {
        report: &report,
        calibration,
        verdict,
    };

    if let Some(report_dir) = &args.report_dir {
        write_report_dir(report_dir, &human_report, &output)?;
    }

    if args.emit_json {
        println!(
            "{}",
            serde_json::to_string_pretty(&output).context("serializing JSON report")?
        );
    } else {
        print!("{human_report}");
    }

    Ok(())
}

#[cfg(any(not(coverage), test))]
#[derive(Debug, PartialEq, Eq)]
struct AnalyzeArgs {
    capture_path: PathBuf,
    emit_json: bool,
    report_dir: Option<PathBuf>,
}

#[cfg(any(not(coverage), test))]
fn parse_args<I, S>(args: I) -> Result<AnalyzeArgs>
where
    I: IntoIterator<Item = S>,
    S: Into<String>,
{
    let args = args.into_iter().map(Into::into).collect::<Vec<_>>();
    if args.is_empty() || args.iter().any(|arg| arg == "--help" || arg == "-h") {
        println!("Usage: lesavka-sync-analyze <capture.mkv> [--json] [--report-dir <dir>]");
        std::process::exit(0);
    }

    let mut emit_json = false;
    let mut report_dir = None::<PathBuf>;
    let mut capture_path = None::<PathBuf>;
    let mut iter = args.into_iter();
    while let Some(arg) = iter.next() {
        if arg == "--json" {
            emit_json = true;
            continue;
        }
        if arg == "--report-dir" {
            let Some(dir) = iter.next() else {
                bail!("--report-dir requires a directory");
            };
            report_dir = Some(PathBuf::from(dir));
            continue;
        }
        if let Some(dir) = arg.strip_prefix("--report-dir=") {
            if dir.is_empty() {
                bail!("--report-dir requires a directory");
            }
            report_dir = Some(PathBuf::from(dir));
            continue;
        }
        if capture_path.is_some() {
            bail!("unexpected extra argument `{arg}`");
        }
        capture_path = Some(PathBuf::from(arg));
    }

    let capture_path = capture_path.context("capture path is required")?;
    Ok(AnalyzeArgs {
        capture_path,
        emit_json,
        report_dir,
    })
}

#[cfg(not(coverage))]
fn format_human_report(
    capture_path: &std::path::Path,
    report: &SyncAnalysisReport,
    calibration: &SyncCalibrationRecommendation,
    verdict: &SyncAnalysisVerdict,
) -> String {
    format!(
        "\
A/V sync report for {capture}
- verdict: {status} ({passed})
- verdict reason: {reason}
- p95 abs skew: {p95:.1} ms
- video onsets: {video_events}
- audio onsets: {audio_events}
- paired pulses: {paired_events}
- first skew: {first_skew:+.1} ms (audio after video is positive)
- last skew: {last_skew:+.1} ms
- mean skew: {mean_skew:+.1} ms
- median skew: {median_skew:+.1} ms
- max abs skew: {max_abs:.1} ms
- drift: {drift:+.1} ms
- calibration ready: {cal_ready}
- recommended audio offset adjust: {audio_adjust:+} us
- alternative video offset adjust: {video_adjust:+} us
- calibration note: {cal_note}
",
        capture = capture_path.display(),
        status = verdict.status,
        passed = if verdict.passed { "pass" } else { "fail" },
        reason = verdict.reason,
        p95 = verdict.p95_abs_skew_ms,
        video_events = report.video_event_count,
        audio_events = report.audio_event_count,
        paired_events = report.paired_event_count,
        first_skew = report.first_skew_ms,
        last_skew = report.last_skew_ms,
        mean_skew = report.mean_skew_ms,
        median_skew = report.median_skew_ms,
        max_abs = report.max_abs_skew_ms,
        drift = report.drift_ms,
        cal_ready = calibration.ready,
        audio_adjust = calibration.recommended_audio_offset_adjust_us,
        video_adjust = calibration.recommended_video_offset_adjust_us,
        cal_note = calibration.note,
    )
}

#[cfg(not(coverage))]
fn write_report_dir(
    report_dir: &std::path::Path,
    human_report: &str,
    output: &SyncAnalyzeOutput<'_>,
) -> Result<()> {
    std::fs::create_dir_all(report_dir)
        .with_context(|| format!("creating report directory {}", report_dir.display()))?;
    std::fs::write(report_dir.join("report.txt"), human_report)
        .with_context(|| format!("writing {}", report_dir.join("report.txt").display()))?;
    std::fs::write(
        report_dir.join("report.json"),
        serde_json::to_string_pretty(output).context("serializing JSON report")?,
    )
    .with_context(|| format!("writing {}", report_dir.join("report.json").display()))?;
    write_events_csv(&report_dir.join("events.csv"), output.report)?;
    Ok(())
}

#[cfg(not(coverage))]
fn write_events_csv(path: &std::path::Path, report: &SyncAnalysisReport) -> Result<()> {
    let mut csv = String::from("event_id,video_time_s,audio_time_s,skew_ms,confidence\n");
    for event in &report.paired_events {
        csv.push_str(&format!(
            "{},{:.9},{:.9},{:.6},{:.6}\n",
            event.event_id, event.video_time_s, event.audio_time_s, event.skew_ms, event.confidence
        ));
    }
    std::fs::write(path, csv).with_context(|| format!("writing {}", path.display()))
}

#[cfg(coverage)]
fn main() {}

#[cfg(test)]
mod tests {
    use super::parse_args;

    #[test]
    fn parse_args_accepts_capture_path_and_json_flag() {
        let args = parse_args(["capture.mkv", "--json"]).expect("args");
        assert_eq!(args.capture_path, std::path::PathBuf::from("capture.mkv"));
        assert!(args.emit_json);
        assert_eq!(args.report_dir, None);
    }

    #[test]
    fn parse_args_accepts_report_dir() {
        let args = parse_args(["capture.mkv", "--report-dir", "/tmp/probe"]).expect("args");
        assert_eq!(args.capture_path, std::path::PathBuf::from("capture.mkv"));
        assert_eq!(
            args.report_dir,
            Some(std::path::PathBuf::from("/tmp/probe"))
        );
    }

    #[test]
    fn parse_args_rejects_extra_positional_arguments() {
        assert!(parse_args(["one.mkv", "two.mkv"]).is_err());
    }

    #[test]
    fn parse_args_requires_a_capture_path() {
        let error = parse_args(["--json"]).expect_err("missing capture path should fail");
        assert!(
            error.to_string().contains("capture path is required"),
            "unexpected error: {error:#}"
        );
    }

    #[test]
    fn coverage_main_stub_is_non_panicking() {
        let _ = super::main();
    }
}