use crate::color;
use crate::section::{RenderContext, SectionOutput};
use crate::shell;
use std::time::Duration;

/// Cached format: "open:N,wip:N,ready:N,closed:N"
pub fn render(ctx: &RenderContext) -> Option<SectionOutput> {
    if !ctx.config.sections.beads.base.enabled {
        return None;
    }

    // Check if .beads/ exists in project dir
    if !ctx.project_dir.join(".beads").is_dir() {
        return None;
    }

    // --no-shell: serve stale cache only
    if ctx.no_shell {
        return render_from_summary(ctx, &ctx.cache.get_stale("beads_stats")?);
    }

    let ttl = Duration::from_secs(ctx.config.sections.beads.ttl);

    let cached = ctx.cache.get("beads_stats", ttl);
    let summary = cached.or_else(|| {
        let out = ctx.shell_results.get("beads").cloned().unwrap_or_else(|| {
            shell::exec_gated(
                ctx.shell_config,
                "br",
                &["stats", "--json"],
                Some(ctx.project_dir.to_str()?),
            )
        })?;
        let summary = parse_stats(&out)?;
        ctx.cache.set("beads_stats", &summary);
        Some(summary)
    })?;

    render_from_summary(ctx, &summary)
}

/// Parse `br stats --json` output into "open:N,wip:N,ready:N,closed:N"
fn parse_stats(json: &str) -> Option<String> {
    let v: serde_json::Value = serde_json::from_str(json).ok()?;
    let s = v.get("summary")?;
    let open = s.get("open_issues")?.as_u64().unwrap_or(0);
    let wip = s.get("in_progress_issues")?.as_u64().unwrap_or(0);
    let ready = s.get("ready_issues")?.as_u64().unwrap_or(0);
    let closed = s.get("closed_issues")?.as_u64().unwrap_or(0);
    Some(format!(
        "open:{open},wip:{wip},ready:{ready},closed:{closed}"
    ))
}

fn render_from_summary(ctx: &RenderContext, summary: &str) -> Option<SectionOutput> {
    let mut open = 0u64;
    let mut wip = 0u64;
    let mut ready = 0u64;
    let mut closed = 0u64;

    for part in summary.split(',') {
        if let Some((key, val)) = part.split_once(':') {
            let n: u64 = val.parse().unwrap_or(0);
            match key {
                "open" => open = n,
                "wip" => wip = n,
                "ready" => ready = n,
                "closed" => closed = n,
                _ => {}
            }
        }
    }

    let cfg = &ctx.config.sections.beads;
    let mut parts: Vec<String> = Vec::new();

    if cfg.show_ready_count && ready > 0 {
        parts.push(format!("{ready} ready"));
    }
    if cfg.show_wip_count && wip > 0 {
        parts.push(format!("{wip} wip"));
    }
    if cfg.show_open_count && open > 0 {
        parts.push(format!("{open} open"));
    }
    if cfg.show_closed_count && closed > 0 {
        parts.push(format!("{closed} done"));
    }

    if parts.is_empty() {
        return None;
    }

    let raw = parts.join(" ");
    let ansi = if ctx.color_enabled {
        format!("{}{raw}{}", color::DIM, color::RESET)
    } else {
        raw.clone()
    };

    Some(SectionOutput { raw, ansi })
}