use crate::cli::render::{self, Icons, Theme, format_number};
use serde::Serialize;
use std::time::Instant;
use tracing::Instrument;
use tracing::{debug, warn};

use crate::Config;
use crate::cli::progress::{format_stage_line, nested_progress, stage_spinner_v2};
use crate::core::error::Result;
use crate::core::metrics::{MetricsLayer, StageTiming};
use crate::core::shutdown::ShutdownSignal;

use super::embed::run_embed;
use super::generate_docs::run_generate_docs;
use super::ingest::{
    DryRunPreview, IngestDisplay, ProjectStatusEnrichment, ProjectSummary, run_ingest,
    run_ingest_dry_run,
};
use super::sync_surgical::run_sync_surgical;

#[derive(Debug, Default)]
pub struct SyncOptions {
    pub full: bool,
    pub force: bool,
    pub no_embed: bool,
    pub no_docs: bool,
    pub no_events: bool,
    pub robot_mode: bool,
    pub dry_run: bool,
    pub issue_iids: Vec<u64>,
    pub mr_iids: Vec<u64>,
    pub project: Option<String>,
    pub preflight_only: bool,
}

impl SyncOptions {
    pub const MAX_SURGICAL_TARGETS: usize = 100;

    pub fn is_surgical(&self) -> bool {
        !self.issue_iids.is_empty() || !self.mr_iids.is_empty()
    }
}

#[derive(Debug, Default, Serialize)]
pub struct SurgicalIids {
    pub issues: Vec<u64>,
    pub merge_requests: Vec<u64>,
}

#[derive(Debug, Serialize)]
pub struct EntitySyncResult {
    pub entity_type: String,
    pub iid: u64,
    pub outcome: String,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub error: Option<String>,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub toctou_reason: Option<String>,
}

#[derive(Debug, Default, Serialize)]
pub struct SyncResult {
    #[serde(skip)]
    pub run_id: String,
    pub issues_updated: usize,
    pub mrs_updated: usize,
    pub discussions_fetched: usize,
    pub resource_events_fetched: usize,
    pub resource_events_failed: usize,
    pub mr_diffs_fetched: usize,
    pub mr_diffs_failed: usize,
    pub documents_regenerated: usize,
    pub documents_errored: usize,
    pub documents_embedded: usize,
    pub embedding_failed: usize,
    pub status_enrichment_errors: usize,
    pub statuses_enriched: usize,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub surgical_mode: Option<bool>,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub surgical_iids: Option<SurgicalIids>,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub entity_results: Option<Vec<EntitySyncResult>>,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub preflight_only: Option<bool>,
    #[serde(skip)]
    pub issue_projects: Vec<ProjectSummary>,
    #[serde(skip)]
    pub mr_projects: Vec<ProjectSummary>,
}

/// Alias for [`Theme::color_icon`] to keep call sites concise.
fn color_icon(icon: &str, has_errors: bool) -> String {
    Theme::color_icon(icon, has_errors)
}

pub async fn run_sync(
    config: &Config,
    options: SyncOptions,
    run_id: Option<&str>,
    signal: &ShutdownSignal,
) -> Result<SyncResult> {
    // Surgical dispatch: if any IIDs specified, route to surgical pipeline
    if options.is_surgical() {
        return run_sync_surgical(config, options, run_id, signal).await;
    }

    let generated_id;
    let run_id = match run_id {
        Some(id) => id,
        None => {
            generated_id = uuid::Uuid::new_v4().simple().to_string();
            &generated_id[..8]
        }
    };
    let span = tracing::info_span!("sync", %run_id);

    async move {
        let mut result = SyncResult {
            run_id: run_id.to_string(),
            ..SyncResult::default()
        };

        // Handle dry_run mode - show preview without making any changes
        if options.dry_run {
            return run_sync_dry_run(config, &options).await;
        }

        let ingest_display = if options.robot_mode {
            IngestDisplay::silent()
        } else {
            IngestDisplay::progress_only()
        };

        // ── Stage: Issues ──
        let stage_start = Instant::now();
        let spinner = stage_spinner_v2(Icons::sync(), "Issues", "fetching...", options.robot_mode);
        debug!("Sync: ingesting issues");
        let issues_result = run_ingest(
            config,
            "issues",
            None,
            options.force,
            options.full,
            false, // dry_run - sync has its own dry_run handling
            ingest_display,
            Some(spinner.clone()),
            signal,
        )
        .await?;
        result.issues_updated = issues_result.issues_upserted;
        result.discussions_fetched += issues_result.discussions_fetched;
        result.resource_events_fetched += issues_result.resource_events_fetched;
        result.resource_events_failed += issues_result.resource_events_failed;
        result.status_enrichment_errors += issues_result.status_enrichment_errors;
        for sep in &issues_result.status_enrichment_projects {
            result.statuses_enriched += sep.enriched;
        }
        result.issue_projects = issues_result.project_summaries;
        let issues_elapsed = stage_start.elapsed();
        if !options.robot_mode {
            let (status_summary, status_has_errors) =
                summarize_status_enrichment(&issues_result.status_enrichment_projects);
            let status_icon = color_icon(
                if status_has_errors {
                    Icons::warning()
                } else {
                    Icons::success()
                },
                status_has_errors,
            );
            let mut status_lines = vec![format_stage_line(
                &status_icon,
                "Status",
                &status_summary,
                issues_elapsed,
            )];
            status_lines.extend(status_sub_rows(&issues_result.status_enrichment_projects));
            print_static_lines(&status_lines);
        }
        let mut issues_summary = format!(
            "{} issues from {} {}",
            format_number(result.issues_updated as i64),
            issues_result.projects_synced,
            if issues_result.projects_synced == 1 { "project" } else { "projects" }
        );
        append_failures(
            &mut issues_summary,
            &[
                ("event failures", issues_result.resource_events_failed),
                ("status errors", issues_result.status_enrichment_errors),
            ],
        );
        let issues_icon = color_icon(
            if issues_result.resource_events_failed > 0 || issues_result.status_enrichment_errors > 0
            {
                Icons::warning()
            } else {
                Icons::success()
            },
            issues_result.resource_events_failed > 0 || issues_result.status_enrichment_errors > 0,
        );
        if options.robot_mode {
            emit_stage_line(&spinner, &issues_icon, "Issues", &issues_summary, issues_elapsed);
        } else {
            let sub_rows = issue_sub_rows(&result.issue_projects);
            emit_stage_block(
                &spinner,
                &issues_icon,
                "Issues",
                &issues_summary,
                issues_elapsed,
                &sub_rows,
            );
        }

        if signal.is_cancelled() {
            debug!("Shutdown requested after issues stage, returning partial sync results");
            return Ok(result);
        }

        // ── Stage: MRs ──
        let stage_start = Instant::now();
        let spinner = stage_spinner_v2(Icons::sync(), "MRs", "fetching...", options.robot_mode);
        debug!("Sync: ingesting merge requests");
        let mrs_result = run_ingest(
            config,
            "mrs",
            None,
            options.force,
            options.full,
            false, // dry_run - sync has its own dry_run handling
            ingest_display,
            Some(spinner.clone()),
            signal,
        )
        .await?;
        result.mrs_updated = mrs_result.mrs_upserted;
        result.discussions_fetched += mrs_result.discussions_fetched;
        result.resource_events_fetched += mrs_result.resource_events_fetched;
        result.resource_events_failed += mrs_result.resource_events_failed;
        result.mr_diffs_fetched += mrs_result.mr_diffs_fetched;
        result.mr_diffs_failed += mrs_result.mr_diffs_failed;
        result.mr_projects = mrs_result.project_summaries;
        let mrs_elapsed = stage_start.elapsed();
        let mut mrs_summary = format!(
            "{} merge requests from {} {}",
            format_number(result.mrs_updated as i64),
            mrs_result.projects_synced,
            if mrs_result.projects_synced == 1 { "project" } else { "projects" }
        );
        append_failures(
            &mut mrs_summary,
            &[
                ("event failures", mrs_result.resource_events_failed),
                ("diff failures", mrs_result.mr_diffs_failed),
            ],
        );
        let mrs_icon = color_icon(
            if mrs_result.resource_events_failed > 0 || mrs_result.mr_diffs_failed > 0 {
                Icons::warning()
            } else {
                Icons::success()
            },
            mrs_result.resource_events_failed > 0 || mrs_result.mr_diffs_failed > 0,
        );
        if options.robot_mode {
            emit_stage_line(&spinner, &mrs_icon, "MRs", &mrs_summary, mrs_elapsed);
        } else {
            let sub_rows = mr_sub_rows(&result.mr_projects);
            emit_stage_block(&spinner, &mrs_icon, "MRs", &mrs_summary, mrs_elapsed, &sub_rows);
        }

        if signal.is_cancelled() {
            debug!("Shutdown requested after MRs stage, returning partial sync results");
            return Ok(result);
        }

        // ── Stage: Docs ──
        if !options.no_docs {
            let stage_start = Instant::now();
            let spinner = stage_spinner_v2(Icons::sync(), "Docs", "generating...", options.robot_mode);
            debug!("Sync: generating documents");

            let docs_bar = nested_progress("Docs", 0, options.robot_mode);
            let docs_bar_clone = docs_bar.clone();
            let docs_cb: Box<dyn Fn(usize, usize)> = Box::new(move |processed, total| {
                if total > 0 {
                    docs_bar_clone.set_length(total as u64);
                    docs_bar_clone.set_position(processed as u64);
                }
            });
            let docs_result = run_generate_docs(config, options.full, None, Some(docs_cb))?;
            result.documents_regenerated = docs_result.regenerated;
            result.documents_errored = docs_result.errored;
            docs_bar.finish_and_clear();
            let mut docs_summary = format!(
                "{} documents generated",
                format_number(result.documents_regenerated as i64),
            );
            append_failures(&mut docs_summary, &[("errors", docs_result.errored)]);
            let docs_icon = color_icon(
                if docs_result.errored > 0 {
                    Icons::warning()
                } else {
                    Icons::success()
                },
                docs_result.errored > 0,
            );
            emit_stage_line(&spinner, &docs_icon, "Docs", &docs_summary, stage_start.elapsed());
        } else {
            debug!("Sync: skipping document generation (--no-docs)");
        }

        // ── Stage: Embed ──
        if !options.no_embed {
            let stage_start = Instant::now();
            let spinner = stage_spinner_v2(Icons::sync(), "Embed", "preparing...", options.robot_mode);
            debug!("Sync: embedding documents");

            let embed_bar = nested_progress("Embed", 0, options.robot_mode);
            let embed_bar_clone = embed_bar.clone();
            let embed_cb: Box<dyn Fn(usize, usize)> = Box::new(move |processed, total| {
                if total > 0 {
                    embed_bar_clone.set_length(total as u64);
                    embed_bar_clone.set_position(processed as u64);
                }
            });
            match run_embed(config, options.full, false, Some(embed_cb), signal).await {
                Ok(embed_result) => {
                    result.documents_embedded = embed_result.docs_embedded;
                    result.embedding_failed = embed_result.failed;
                    embed_bar.finish_and_clear();
                    let mut embed_summary = format!(
                        "{} chunks embedded",
                        format_number(embed_result.chunks_embedded as i64),
                    );
                    let mut tail_parts = Vec::new();
                    if embed_result.failed > 0 {
                        tail_parts.push(format!("{} failed", embed_result.failed));
                    }
                    if embed_result.skipped > 0 {
                        tail_parts.push(format!("{} skipped", embed_result.skipped));
                    }
                    if !tail_parts.is_empty() {
                        embed_summary.push_str(&format!(" ({})", tail_parts.join(", ")));
                    }
                    let embed_icon = color_icon(
                        if embed_result.failed > 0 {
                            Icons::warning()
                        } else {
                            Icons::success()
                        },
                        embed_result.failed > 0,
                    );
                    emit_stage_line(
                        &spinner,
                        &embed_icon,
                        "Embed",
                        &embed_summary,
                        stage_start.elapsed(),
                    );
                }
                Err(e) => {
                    embed_bar.finish_and_clear();
                    let warn_summary = format!("skipped ({})", e);
                    let warn_icon = color_icon(Icons::warning(), true);
                    emit_stage_line(
                        &spinner,
                        &warn_icon,
                        "Embed",
                        &warn_summary,
                        stage_start.elapsed(),
                    );
                    warn!(error = %e, "Embedding stage failed (Ollama may be unavailable), continuing");
                }
            }
        } else {
            debug!("Sync: skipping embedding (--no-embed)");
        }

        debug!(
            issues = result.issues_updated,
            mrs = result.mrs_updated,
            discussions = result.discussions_fetched,
            resource_events = result.resource_events_fetched,
            resource_events_failed = result.resource_events_failed,
            mr_diffs = result.mr_diffs_fetched,
            mr_diffs_failed = result.mr_diffs_failed,
            docs = result.documents_regenerated,
            embedded = result.documents_embedded,
            "Sync pipeline complete"
        );

        Ok(result)
    }
    .instrument(span)
    .await
}

pub fn print_sync(
    result: &SyncResult,
    elapsed: std::time::Duration,
    metrics: Option<&MetricsLayer>,
    show_timings: bool,
) {
    let has_data = result.issues_updated > 0
        || result.mrs_updated > 0
        || result.discussions_fetched > 0
        || result.resource_events_fetched > 0
        || result.mr_diffs_fetched > 0
        || result.documents_regenerated > 0
        || result.documents_embedded > 0
        || result.statuses_enriched > 0;
    let has_failures = result.resource_events_failed > 0
        || result.mr_diffs_failed > 0
        || result.status_enrichment_errors > 0
        || result.documents_errored > 0
        || result.embedding_failed > 0;

    if !has_data && !has_failures {
        println!(
            "\n  {} ({})\n",
            Theme::dim().render("Already up to date"),
            Theme::timing().render(&format!("{:.1}s", elapsed.as_secs_f64()))
        );
    } else {
        let headline = if has_failures {
            Theme::warning().bold().render("Sync completed with issues")
        } else {
            Theme::success().bold().render("Synced")
        };
        println!(
            "\n  {} {} issues and {} MRs in {}",
            headline,
            Theme::info()
                .bold()
                .render(&result.issues_updated.to_string()),
            Theme::info().bold().render(&result.mrs_updated.to_string()),
            Theme::timing().render(&format!("{:.1}s", elapsed.as_secs_f64()))
        );

        // Detail: supporting counts, compact middle-dot format, zero-suppressed
        let mut details: Vec<String> = Vec::new();
        if result.discussions_fetched > 0 {
            details.push(format!(
                "{} {}",
                Theme::info().render(&result.discussions_fetched.to_string()),
                Theme::dim().render("discussions")
            ));
        }
        if result.resource_events_fetched > 0 {
            details.push(format!(
                "{} {}",
                Theme::info().render(&result.resource_events_fetched.to_string()),
                Theme::dim().render("events")
            ));
        }
        if result.mr_diffs_fetched > 0 {
            details.push(format!(
                "{} {}",
                Theme::info().render(&result.mr_diffs_fetched.to_string()),
                Theme::dim().render("diffs")
            ));
        }
        if result.statuses_enriched > 0 {
            details.push(format!(
                "{} {}",
                Theme::info().render(&result.statuses_enriched.to_string()),
                Theme::dim().render("statuses updated")
            ));
        }
        if !details.is_empty() {
            let sep = Theme::dim().render(" \u{b7} ");
            println!("  {}", details.join(&sep));
        }

        // Documents: regeneration + embedding as a second detail line
        let mut doc_parts: Vec<String> = Vec::new();
        if result.documents_regenerated > 0 {
            doc_parts.push(format!(
                "{} {}",
                Theme::info().render(&result.documents_regenerated.to_string()),
                Theme::dim().render("docs regenerated")
            ));
        }
        if result.documents_embedded > 0 {
            doc_parts.push(format!(
                "{} {}",
                Theme::info().render(&result.documents_embedded.to_string()),
                Theme::dim().render("embedded")
            ));
        }
        if result.documents_errored > 0 {
            doc_parts
                .push(Theme::error().render(&format!("{} doc errors", result.documents_errored)));
        }
        if !doc_parts.is_empty() {
            let sep = Theme::dim().render(" \u{b7} ");
            println!("  {}", doc_parts.join(&sep));
        }

        // Errors: visually prominent, only if non-zero
        let mut errors: Vec<String> = Vec::new();
        if result.resource_events_failed > 0 {
            errors.push(format!("{} event failures", result.resource_events_failed));
        }
        if result.mr_diffs_failed > 0 {
            errors.push(format!("{} diff failures", result.mr_diffs_failed));
        }
        if result.status_enrichment_errors > 0 {
            errors.push(format!("{} status errors", result.status_enrichment_errors));
        }
        if result.embedding_failed > 0 {
            errors.push(format!("{} embedding failures", result.embedding_failed));
        }
        if !errors.is_empty() {
            println!("  {}", Theme::error().render(&errors.join(" \u{b7} ")));
        }

        println!();
    }

    if let Some(metrics) = metrics {
        let stages = metrics.extract_timings();
        if should_print_timings(show_timings, &stages) {
            print_timing_summary(&stages);
        }
    }
}

fn issue_sub_rows(projects: &[ProjectSummary]) -> Vec<String> {
    projects
        .iter()
        .map(|p| {
            let mut parts: Vec<String> = Vec::new();
            parts.push(format!(
                "{} {}",
                p.items_upserted,
                if p.items_upserted == 1 {
                    "issue"
                } else {
                    "issues"
                }
            ));
            if p.discussions_synced > 0 {
                parts.push(format!("{} discussions", p.discussions_synced));
            }
            if p.statuses_seen > 0 || p.statuses_enriched > 0 {
                parts.push(format!("{} statuses updated", p.statuses_enriched));
            }
            if p.events_fetched > 0 {
                parts.push(format!("{} events", p.events_fetched));
            }
            if p.status_errors > 0 {
                parts.push(Theme::warning().render(&format!("{} status errors", p.status_errors)));
            }
            if p.events_failed > 0 {
                parts.push(Theme::warning().render(&format!("{} event failures", p.events_failed)));
            }
            let sep = Theme::dim().render(" \u{b7} ");
            let detail = parts.join(&sep);
            let path = Theme::muted().render(&format!("{:<30}", p.path));
            format!("      {path} {detail}")
        })
        .collect()
}

fn status_sub_rows(projects: &[ProjectStatusEnrichment]) -> Vec<String> {
    projects
        .iter()
        .map(|p| {
            let total_errors = p.partial_errors + usize::from(p.error.is_some());
            let mut parts: Vec<String> = vec![format!("{} statuses updated", p.enriched)];
            if p.cleared > 0 {
                parts.push(format!("{} cleared", p.cleared));
            }
            if p.seen > 0 {
                parts.push(format!("{} seen", p.seen));
            }
            if total_errors > 0 {
                parts.push(Theme::warning().render(&format!("{} errors", total_errors)));
            } else if p.mode == "skipped" {
                if let Some(reason) = &p.reason {
                    parts.push(Theme::dim().render(&format!("skipped ({reason})")));
                } else {
                    parts.push(Theme::dim().render("skipped"));
                }
            }
            let sep = Theme::dim().render(" \u{b7} ");
            let detail = parts.join(&sep);
            let path = Theme::muted().render(&format!("{:<30}", p.path));
            format!("      {path} {detail}")
        })
        .collect()
}

fn mr_sub_rows(projects: &[ProjectSummary]) -> Vec<String> {
    projects
        .iter()
        .map(|p| {
            let mut parts: Vec<String> = Vec::new();
            parts.push(format!(
                "{} {}",
                p.items_upserted,
                if p.items_upserted == 1 { "MR" } else { "MRs" }
            ));
            if p.discussions_synced > 0 {
                parts.push(format!("{} discussions", p.discussions_synced));
            }
            if p.mr_diffs_fetched > 0 {
                parts.push(format!("{} diffs", p.mr_diffs_fetched));
            }
            if p.events_fetched > 0 {
                parts.push(format!("{} events", p.events_fetched));
            }
            if p.mr_diffs_failed > 0 {
                parts
                    .push(Theme::warning().render(&format!("{} diff failures", p.mr_diffs_failed)));
            }
            if p.events_failed > 0 {
                parts.push(Theme::warning().render(&format!("{} event failures", p.events_failed)));
            }
            let sep = Theme::dim().render(" \u{b7} ");
            let detail = parts.join(&sep);
            let path = Theme::muted().render(&format!("{:<30}", p.path));
            format!("      {path} {detail}")
        })
        .collect()
}

fn emit_stage_line(
    pb: &indicatif::ProgressBar,
    icon: &str,
    label: &str,
    summary: &str,
    elapsed: std::time::Duration,
) {
    pb.finish_and_clear();
    print_static_lines(&[format_stage_line(icon, label, summary, elapsed)]);
}

fn emit_stage_block(
    pb: &indicatif::ProgressBar,
    icon: &str,
    label: &str,
    summary: &str,
    elapsed: std::time::Duration,
    sub_rows: &[String],
) {
    pb.finish_and_clear();
    let mut lines = Vec::with_capacity(1 + sub_rows.len());
    lines.push(format_stage_line(icon, label, summary, elapsed));
    lines.extend(sub_rows.iter().cloned());
    print_static_lines(&lines);
}

fn print_static_lines(lines: &[String]) {
    crate::cli::progress::multi().suspend(|| {
        for line in lines {
            println!("{line}");
        }
    });
}

fn should_print_timings(show_timings: bool, stages: &[StageTiming]) -> bool {
    show_timings && !stages.is_empty()
}

fn append_failures(summary: &mut String, failures: &[(&str, usize)]) {
    let rendered: Vec<String> = failures
        .iter()
        .filter_map(|(label, count)| {
            (*count > 0).then_some(Theme::warning().render(&format!("{count} {label}")))
        })
        .collect();
    if !rendered.is_empty() {
        summary.push_str(&format!(" ({})", rendered.join(", ")));
    }
}

fn summarize_status_enrichment(projects: &[ProjectStatusEnrichment]) -> (String, bool) {
    let statuses_enriched: usize = projects.iter().map(|p| p.enriched).sum();
    let statuses_seen: usize = projects.iter().map(|p| p.seen).sum();
    let statuses_cleared: usize = projects.iter().map(|p| p.cleared).sum();
    let status_errors: usize = projects
        .iter()
        .map(|p| p.partial_errors + usize::from(p.error.is_some()))
        .sum();
    let skipped = projects.iter().filter(|p| p.mode == "skipped").count();

    let mut parts = vec![format!(
        "{} statuses updated",
        format_number(statuses_enriched as i64)
    )];
    if statuses_cleared > 0 {
        parts.push(format!(
            "{} cleared",
            format_number(statuses_cleared as i64)
        ));
    }
    if statuses_seen > 0 {
        parts.push(format!("{} seen", format_number(statuses_seen as i64)));
    }
    if status_errors > 0 {
        parts.push(format!("{} errors", format_number(status_errors as i64)));
    } else if projects.is_empty() || skipped == projects.len() {
        parts.push("skipped".to_string());
    }

    (parts.join(" \u{b7} "), status_errors > 0)
}

fn section(title: &str) {
    println!("{}", render::section_divider(title));
}

fn print_timing_summary(stages: &[StageTiming]) {
    section("Timing");
    for stage in stages {
        for sub in &stage.sub_stages {
            print_stage_line(sub, 1);
        }
    }
}

fn print_stage_line(stage: &StageTiming, depth: usize) {
    let indent = "  ".repeat(depth);
    let name = if let Some(ref project) = stage.project {
        format!("{} ({})", stage.name, project)
    } else {
        stage.name.clone()
    };
    let pad_width = 30_usize.saturating_sub(indent.len() + name.len());
    let dots = Theme::dim().render(&".".repeat(pad_width.max(2)));

    let time_str = Theme::bold().render(&format!("{:.1}s", stage.elapsed_ms as f64 / 1000.0));

    let mut parts: Vec<String> = Vec::new();
    if stage.items_processed > 0 {
        parts.push(format!("{} items", stage.items_processed));
    }
    if stage.errors > 0 {
        parts.push(Theme::error().render(&format!("{} errors", stage.errors)));
    }
    if stage.rate_limit_hits > 0 {
        parts.push(Theme::warning().render(&format!("{} rate limits", stage.rate_limit_hits)));
    }

    if parts.is_empty() {
        println!("{indent}{name} {dots} {time_str}");
    } else {
        let suffix = parts.join(" \u{b7} ");
        println!("{indent}{name} {dots} {time_str} ({suffix})");
    }

    for sub in &stage.sub_stages {
        print_stage_line(sub, depth + 1);
    }
}

#[derive(Serialize)]
struct SyncJsonOutput<'a> {
    ok: bool,
    data: &'a SyncResult,
    meta: SyncMeta,
}

#[derive(Serialize)]
struct SyncMeta {
    run_id: String,
    elapsed_ms: u64,
    #[serde(skip_serializing_if = "Vec::is_empty")]
    stages: Vec<StageTiming>,
}

pub fn print_sync_json(result: &SyncResult, elapsed_ms: u64, metrics: Option<&MetricsLayer>) {
    let stages = metrics.map_or_else(Vec::new, MetricsLayer::extract_timings);
    let output = SyncJsonOutput {
        ok: true,
        data: result,
        meta: SyncMeta {
            run_id: result.run_id.clone(),
            elapsed_ms,
            stages,
        },
    };
    match serde_json::to_string(&output) {
        Ok(json) => println!("{json}"),
        Err(e) => eprintln!("Error serializing to JSON: {e}"),
    }
}

#[derive(Debug, Default, Serialize)]
pub struct SyncDryRunResult {
    pub issues_preview: DryRunPreview,
    pub mrs_preview: DryRunPreview,
    pub would_generate_docs: bool,
    pub would_embed: bool,
}

async fn run_sync_dry_run(config: &Config, options: &SyncOptions) -> Result<SyncResult> {
    // Get dry run previews for both issues and MRs
    let issues_preview = run_ingest_dry_run(config, "issues", None, options.full)?;
    let mrs_preview = run_ingest_dry_run(config, "mrs", None, options.full)?;

    let dry_result = SyncDryRunResult {
        issues_preview,
        mrs_preview,
        would_generate_docs: !options.no_docs,
        would_embed: !options.no_embed,
    };

    if options.robot_mode {
        print_sync_dry_run_json(&dry_result);
    } else {
        print_sync_dry_run(&dry_result);
    }

    // Return an empty SyncResult since this is just a preview
    Ok(SyncResult::default())
}

pub fn print_sync_dry_run(result: &SyncDryRunResult) {
    println!(
        "\n  {} {}",
        Theme::info().bold().render("Dry run"),
        Theme::dim().render("(no changes will be made)")
    );

    print_dry_run_entity("Issues", &result.issues_preview);
    print_dry_run_entity("Merge Requests", &result.mrs_preview);

    // Pipeline stages
    section("Pipeline");
    let mut stages: Vec<String> = Vec::new();
    if result.would_generate_docs {
        stages.push("generate-docs".to_string());
    } else {
        stages.push(Theme::dim().render("generate-docs (skip)"));
    }
    if result.would_embed {
        stages.push("embed".to_string());
    } else {
        stages.push(Theme::dim().render("embed (skip)"));
    }
    println!("  {}", stages.join(" \u{b7} "));
}

fn print_dry_run_entity(label: &str, preview: &DryRunPreview) {
    section(label);
    let mode = if preview.sync_mode == "full" {
        Theme::warning().render("full")
    } else {
        Theme::success().render("incremental")
    };
    println!("  {} \u{b7} {} projects", mode, preview.projects.len());
    for project in &preview.projects {
        let sync_status = if !project.has_cursor {
            Theme::warning().render("initial sync")
        } else {
            Theme::success().render("incremental")
        };
        if project.existing_count > 0 {
            println!(
                "    {} \u{b7} {} \u{b7} {} existing",
                &project.path, sync_status, project.existing_count
            );
        } else {
            println!("    {} \u{b7} {}", &project.path, sync_status);
        }
    }
}

#[derive(Serialize)]
struct SyncDryRunJsonOutput {
    ok: bool,
    dry_run: bool,
    data: SyncDryRunJsonData,
}

#[derive(Serialize)]
struct SyncDryRunJsonData {
    stages: Vec<SyncDryRunStage>,
}

#[derive(Serialize)]
struct SyncDryRunStage {
    name: String,
    would_run: bool,
    #[serde(skip_serializing_if = "Option::is_none")]
    preview: Option<DryRunPreview>,
}

pub fn print_sync_dry_run_json(result: &SyncDryRunResult) {
    let output = SyncDryRunJsonOutput {
        ok: true,
        dry_run: true,
        data: SyncDryRunJsonData {
            stages: vec![
                SyncDryRunStage {
                    name: "ingest_issues".to_string(),
                    would_run: true,
                    preview: Some(result.issues_preview.clone()),
                },
                SyncDryRunStage {
                    name: "ingest_mrs".to_string(),
                    would_run: true,
                    preview: Some(result.mrs_preview.clone()),
                },
                SyncDryRunStage {
                    name: "generate_docs".to_string(),
                    would_run: result.would_generate_docs,
                    preview: None,
                },
                SyncDryRunStage {
                    name: "embed".to_string(),
                    would_run: result.would_embed,
                    preview: None,
                },
            ],
        },
    };

    match serde_json::to_string(&output) {
        Ok(json) => println!("{json}"),
        Err(e) => eprintln!("Error serializing to JSON: {e}"),
    }
}

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

    fn default_options() -> SyncOptions {
        SyncOptions {
            full: false,
            force: false,
            no_embed: false,
            no_docs: false,
            no_events: false,
            robot_mode: false,
            dry_run: false,
            issue_iids: vec![],
            mr_iids: vec![],
            project: None,
            preflight_only: false,
        }
    }

    #[test]
    fn append_failures_skips_zeroes() {
        let mut summary = "base".to_string();
        append_failures(&mut summary, &[("errors", 0), ("failures", 0)]);
        assert_eq!(summary, "base");
    }

    #[test]
    fn append_failures_renders_non_zero_counts() {
        let mut summary = "base".to_string();
        append_failures(&mut summary, &[("errors", 2), ("failures", 1)]);
        assert!(summary.contains("base"));
        assert!(summary.contains("2 errors"));
        assert!(summary.contains("1 failures"));
    }

    #[test]
    fn summarize_status_enrichment_reports_skipped_when_all_skipped() {
        let projects = vec![ProjectStatusEnrichment {
            path: "vs/typescript-code".to_string(),
            mode: "skipped".to_string(),
            reason: None,
            seen: 0,
            enriched: 0,
            cleared: 0,
            without_widget: 0,
            partial_errors: 0,
            first_partial_error: None,
            error: None,
        }];

        let (summary, has_errors) = summarize_status_enrichment(&projects);
        assert!(summary.contains("0 statuses updated"));
        assert!(summary.contains("skipped"));
        assert!(!has_errors);
    }

    #[test]
    fn summarize_status_enrichment_reports_errors() {
        let projects = vec![ProjectStatusEnrichment {
            path: "vs/typescript-code".to_string(),
            mode: "fetched".to_string(),
            reason: None,
            seen: 3,
            enriched: 1,
            cleared: 1,
            without_widget: 0,
            partial_errors: 2,
            first_partial_error: None,
            error: Some("boom".to_string()),
        }];

        let (summary, has_errors) = summarize_status_enrichment(&projects);
        assert!(summary.contains("1 statuses updated"));
        assert!(summary.contains("1 cleared"));
        assert!(summary.contains("3 seen"));
        assert!(summary.contains("3 errors"));
        assert!(has_errors);
    }

    #[test]
    fn should_print_timings_only_when_enabled_and_non_empty() {
        let stages = vec![StageTiming {
            name: "x".to_string(),
            elapsed_ms: 10,
            items_processed: 0,
            items_skipped: 0,
            errors: 0,
            rate_limit_hits: 0,
            retries: 0,
            project: None,
            sub_stages: vec![],
        }];

        assert!(should_print_timings(true, &stages));
        assert!(!should_print_timings(false, &stages));
        assert!(!should_print_timings(true, &[]));
    }

    #[test]
    fn issue_sub_rows_include_project_and_statuses() {
        let rows = issue_sub_rows(&[ProjectSummary {
            path: "vs/typescript-code".to_string(),
            items_upserted: 2,
            discussions_synced: 0,
            events_fetched: 0,
            events_failed: 0,
            statuses_enriched: 1,
            statuses_seen: 5,
            status_errors: 0,
            mr_diffs_fetched: 0,
            mr_diffs_failed: 0,
        }]);

        assert_eq!(rows.len(), 1);
        assert!(rows[0].contains("vs/typescript-code"));
        assert!(rows[0].contains("2 issues"));
        assert!(rows[0].contains("1 statuses updated"));
    }

    #[test]
    fn mr_sub_rows_include_project_and_diff_failures() {
        let rows = mr_sub_rows(&[ProjectSummary {
            path: "vs/python-code".to_string(),
            items_upserted: 3,
            discussions_synced: 0,
            events_fetched: 0,
            events_failed: 0,
            statuses_enriched: 0,
            statuses_seen: 0,
            status_errors: 0,
            mr_diffs_fetched: 4,
            mr_diffs_failed: 1,
        }]);

        assert_eq!(rows.len(), 1);
        assert!(rows[0].contains("vs/python-code"));
        assert!(rows[0].contains("3 MRs"));
        assert!(rows[0].contains("4 diffs"));
        assert!(rows[0].contains("1 diff failures"));
    }

    #[test]
    fn status_sub_rows_include_project_and_skip_reason() {
        let rows = status_sub_rows(&[ProjectStatusEnrichment {
            path: "vs/python-code".to_string(),
            mode: "skipped".to_string(),
            reason: Some("disabled".to_string()),
            seen: 0,
            enriched: 0,
            cleared: 0,
            without_widget: 0,
            partial_errors: 0,
            first_partial_error: None,
            error: None,
        }]);

        assert_eq!(rows.len(), 1);
        assert!(rows[0].contains("vs/python-code"));
        assert!(rows[0].contains("0 statuses updated"));
        assert!(rows[0].contains("skipped (disabled)"));
    }

    #[test]
    fn is_surgical_with_issues() {
        let opts = SyncOptions {
            issue_iids: vec![1],
            ..default_options()
        };
        assert!(opts.is_surgical());
    }

    #[test]
    fn is_surgical_with_mrs() {
        let opts = SyncOptions {
            mr_iids: vec![10],
            ..default_options()
        };
        assert!(opts.is_surgical());
    }

    #[test]
    fn is_surgical_empty() {
        let opts = default_options();
        assert!(!opts.is_surgical());
    }

    #[test]
    fn max_surgical_targets_is_100() {
        assert_eq!(SyncOptions::MAX_SURGICAL_TARGETS, 100);
    }

    #[test]
    fn sync_result_default_omits_surgical_fields() {
        let result = SyncResult::default();
        let json = serde_json::to_value(&result).unwrap();
        assert!(json.get("surgical_mode").is_none());
        assert!(json.get("surgical_iids").is_none());
        assert!(json.get("entity_results").is_none());
        assert!(json.get("preflight_only").is_none());
    }

    #[test]
    fn sync_result_with_surgical_fields_serializes_correctly() {
        let result = SyncResult {
            surgical_mode: Some(true),
            surgical_iids: Some(SurgicalIids {
                issues: vec![7, 42],
                merge_requests: vec![10],
            }),
            entity_results: Some(vec![
                EntitySyncResult {
                    entity_type: "issue".to_string(),
                    iid: 7,
                    outcome: "synced".to_string(),
                    error: None,
                    toctou_reason: None,
                },
                EntitySyncResult {
                    entity_type: "issue".to_string(),
                    iid: 42,
                    outcome: "skipped_toctou".to_string(),
                    error: None,
                    toctou_reason: Some("updated_at changed".to_string()),
                },
            ]),
            preflight_only: Some(false),
            ..SyncResult::default()
        };
        let json = serde_json::to_value(&result).unwrap();
        assert_eq!(json["surgical_mode"], true);
        assert_eq!(json["surgical_iids"]["issues"], serde_json::json!([7, 42]));
        assert_eq!(json["entity_results"].as_array().unwrap().len(), 2);
        assert_eq!(json["entity_results"][1]["outcome"], "skipped_toctou");
        assert_eq!(json["preflight_only"], false);
    }

    #[test]
    fn entity_sync_result_omits_none_fields() {
        let entity = EntitySyncResult {
            entity_type: "merge_request".to_string(),
            iid: 10,
            outcome: "synced".to_string(),
            error: None,
            toctou_reason: None,
        };
        let json = serde_json::to_value(&entity).unwrap();
        assert!(json.get("error").is_none());
        assert!(json.get("toctou_reason").is_none());
        assert!(json.get("entity_type").is_some());
    }

    #[test]
    fn is_surgical_with_both_issues_and_mrs() {
        let opts = SyncOptions {
            issue_iids: vec![1, 2],
            mr_iids: vec![10],
            ..default_options()
        };
        assert!(opts.is_surgical());
    }

    #[test]
    fn is_not_surgical_with_only_project() {
        let opts = SyncOptions {
            project: Some("group/repo".to_string()),
            ..default_options()
        };
        assert!(!opts.is_surgical());
    }
}