//! Epic work-item creation operations.
//!
//! Epics are shared-context containers that group related stories, bugs, spikes, and
//! refactors under a common goal. They are stored in the CRDT items list with
//! `type: epic` and are not pipeline-driven (no stage advancement).

use std::path::Path;

use super::super::{next_item_number, slugify_name, write_story_content};

/// Create an epic file and store it in the database.
///
/// Returns the epic_id (e.g. `"880"`).
pub fn create_epic_file(
    root: &Path,
    name: &str,
    goal: &str,
    motivation: Option<&str>,
    key_files: Option<&str>,
    success_criteria: Option<&[String]>,
) -> Result<String, String> {
    let epic_number = next_item_number(root)?;
    let slug = slugify_name(name);

    if slug.is_empty() {
        return Err("Name must contain at least one alphanumeric character.".to_string());
    }

    let epic_id = format!("{epic_number}");

    let mut content = String::new();
    content.push_str("---\n");
    content.push_str("type: epic\n");
    content.push_str(&format!("name: \"{}\"\n", name.replace('"', "\\\"")));
    content.push_str("---\n\n");
    content.push_str(&format!("# Epic {epic_number}: {name}\n\n"));

    content.push_str("## Goal\n\n");
    content.push_str(goal);
    content.push_str("\n\n");

    content.push_str("## Motivation\n\n");
    if let Some(m) = motivation {
        content.push_str(m);
        content.push('\n');
    } else {
        content.push_str("- TBD\n");
    }
    content.push('\n');

    content.push_str("## Key Files\n\n");
    if let Some(kf) = key_files {
        content.push_str(kf);
        content.push('\n');
    } else {
        content.push_str("- TBD\n");
    }
    content.push('\n');

    content.push_str("## Success Criteria\n\n");
    match success_criteria {
        Some(criteria) if !criteria.is_empty() => {
            for c in criteria {
                content.push_str(&format!("- {c}\n"));
            }
        }
        _ => {
            content.push_str("- TBD\n");
        }
    }

    // Epics are stored in backlog (no pipeline advancement).
    write_story_content(root, &epic_id, "1_backlog", &content);

    Ok(epic_id)
}