dkp-gen-core 0.3.0

use serde_json::Value;

use crate::error::GenResult;
use crate::pipeline::context::PipelineContext;
use crate::prompt::{extract_json, templates};

/// Fill in audience/intended_use/known_limitations via LLM and refresh update_date.
pub async fn update_meta(ctx: &PipelineContext) -> GenResult<()> {
    let manifest_path = ctx.pack_dir.join("manifest.json");
    if !manifest_path.exists() {
        return Ok(());
    }

    let content = std::fs::read_to_string(&manifest_path)?;
    let mut manifest: Value = serde_json::from_str(&content)?;

    let needs_fill = ["audience", "intended_use", "known_limitations"]
        .iter()
        .any(|f| {
            manifest[f]
                .as_str()
                .map(|s| s.trim().is_empty() || s.starts_with("TODO"))
                .unwrap_or(true)
        });

    if needs_fill {
        let (sys, user) = templates::prompt_manifest_meta(&ctx.domain, &ctx.pack_name);
        let raw = ctx.generate("manifest_meta", &sys, &user).await?;
        if let Ok(meta) = extract_json(&raw) {
            for field in ["audience", "intended_use", "known_limitations"] {
                if let Some(v) = meta[field].as_str() {
                    if !v.trim().is_empty() {
                        manifest[field] = Value::String(v.to_string());
                    }
                }
            }
        }
    }

    // Refresh update_date
    manifest["update_date"] = Value::String(today_iso8601());
    ctx.write_json(&manifest_path, &manifest)
}

fn today_iso8601() -> String {
    use std::time::{SystemTime, UNIX_EPOCH};
    let secs = SystemTime::now()
        .duration_since(UNIX_EPOCH)
        .map(|d| d.as_secs())
        .unwrap_or(0);
    let days = secs / 86400;
    let z = days as i64 + 719468;
    let era = if z >= 0 { z } else { z - 146096 } / 146097;
    let doe = z - era * 146097;
    let yoe = (doe - doe / 1460 + doe / 36524 - doe / 146096) / 365;
    let y = yoe + era * 400;
    let doy = doe - (365 * yoe + yoe / 4 - yoe / 100);
    let mp = (5 * doy + 2) / 153;
    let d = doy - (153 * mp + 2) / 5 + 1;
    let m = if mp < 10 { mp + 3 } else { mp - 9 };
    let y = if m <= 2 { y + 1 } else { y };
    format!("{y:04}-{m:02}-{d:02}")
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::config::GenConfig;
    use crate::llm::mock::MockClient;
    use std::collections::HashMap;
    use std::sync::Arc;
    use tempfile::TempDir;

    fn test_ctx(tmp: &TempDir, fixtures: HashMap<String, String>) -> PipelineContext {
        PipelineContext {
            pack_dir: tmp.path().to_path_buf(),
            domain: "testing".to_string(),
            pack_name: "test-pack".to_string(),
            config: GenConfig::default(),
            client: Arc::new(MockClient::new(fixtures, "")),
            progress: None,
            verbose: false,
        }
    }

    #[tokio::test]
    async fn update_meta_no_manifest_is_noop() {
        let tmp = TempDir::new().unwrap();
        let ctx = test_ctx(&tmp, HashMap::new());
        // No manifest.json exists; should return Ok without erroring.
        update_meta(&ctx).await.unwrap();
        assert!(!tmp.path().join("manifest.json").exists());
    }

    #[tokio::test]
    async fn update_meta_skips_llm_when_fields_already_filled() {
        let tmp = TempDir::new().unwrap();
        std::fs::write(
            tmp.path().join("manifest.json"),
            r#"{"audience": "engineers", "intended_use": "support", "known_limitations": "none", "update_date": "2020-01-01"}"#,
        )
        .unwrap();
        // No fixtures registered; if the LLM were called this would error out.
        let ctx = test_ctx(&tmp, HashMap::new());

        update_meta(&ctx).await.unwrap();

        let content = std::fs::read_to_string(tmp.path().join("manifest.json")).unwrap();
        let manifest: Value = serde_json::from_str(&content).unwrap();
        assert_eq!(manifest["audience"], "engineers");
        assert_ne!(manifest["update_date"], "2020-01-01");
    }

    #[tokio::test]
    async fn update_meta_fills_empty_fields_via_llm() {
        let tmp = TempDir::new().unwrap();
        std::fs::write(
            tmp.path().join("manifest.json"),
            r#"{"audience": "", "intended_use": "TODO", "known_limitations": "", "update_date": "2020-01-01"}"#,
        )
        .unwrap();
        let mut fixtures = HashMap::new();
        fixtures.insert(
            "manifest".to_string(),
            r#"{"audience": "filled audience", "intended_use": "filled use", "known_limitations": "filled limits"}"#.to_string(),
        );
        let ctx = test_ctx(&tmp, fixtures);

        update_meta(&ctx).await.unwrap();

        let content = std::fs::read_to_string(tmp.path().join("manifest.json")).unwrap();
        let manifest: Value = serde_json::from_str(&content).unwrap();
        assert_eq!(manifest["audience"], "filled audience");
        assert_eq!(manifest["intended_use"], "filled use");
        assert_eq!(manifest["known_limitations"], "filled limits");
    }

    #[test]
    fn today_iso8601_produces_well_formed_date() {
        let date = today_iso8601();
        assert_eq!(date.len(), 10);
        assert_eq!(date.chars().nth(4), Some('-'));
        assert_eq!(date.chars().nth(7), Some('-'));
    }
}