// identity.rs — Identity file discovery and context assembly
//
// Discovers and loads the agent's identity: instruction files (CLAUDE.md,
// POC.md), memory nodes, and the system prompt.

use anyhow::Result;
use std::path::{Path, PathBuf};

use crate::agent::tools::memory::memory_render;

/// Walk from cwd to git root collecting instruction files (CLAUDE.md / POC.md).
///
/// On Anthropic models, loads CLAUDE.md. On other models, prefers POC.md
/// (omits Claude-specific RLHF corrections). If only one exists, it's
/// always loaded regardless of model.
fn find_context_files(cwd: &Path, prompt_file: &str) -> Vec<PathBuf> {
    let prefer_poc = prompt_file == "POC.md";

    let mut found = Vec::new();
    let mut dir = Some(cwd);
    while let Some(d) = dir {
        for name in ["POC.md", "CLAUDE.md", ".claude/CLAUDE.md"] {
            let path = d.join(name);
            if path.exists() {
                found.push(path);
            }
        }
        if d.join(".git").exists() { break; }
        dir = d.parent();
    }

    if let Some(home) = dirs::home_dir() {
        let global = home.join(".claude/CLAUDE.md");
        if global.exists() && !found.contains(&global) {
            found.push(global);
        }
    }

    // Filter: when preferring POC.md, skip bare CLAUDE.md (keep .claude/CLAUDE.md).
    // When preferring CLAUDE.md, skip POC.md entirely.
    let has_poc = found.iter().any(|p| p.file_name().map_or(false, |n| n == "POC.md"));
    if !prefer_poc {
        found.retain(|p| p.file_name().map_or(true, |n| n != "POC.md"));
    } else if has_poc {
        found.retain(|p| match p.file_name().and_then(|n| n.to_str()) {
            Some("CLAUDE.md") => p.parent().and_then(|par| par.file_name())
                .map_or(true, |n| n == ".claude"),
            _ => true,
        });
    }

    found.reverse(); // global first, project-specific overrides
    found
}

/// Load memory nodes from the store.
async fn load_memory_nodes(keys: &[String]) -> Vec<(String, String)> {
    let mut memories: Vec<(String, String)> = Vec::new();

    for key in keys {
        if let Ok(c) = memory_render(None, key, Some(true)).await {
            if !c.trim().is_empty() {
                memories.push((key.clone(), c));
            }
        }
    }

    memories
}

/// Context message: instruction files + memory nodes.
pub async fn assemble_context_message(cwd: &Path, prompt_file: &str, _memory_project: Option<&Path>, personality_nodes: &[String]) -> Result<(Vec<(String, String)>, usize, usize)> {
    let mut parts: Vec<(String, String)> = vec![
        ("Preamble".to_string(),
         "Everything below is already loaded — your identity, instructions, \
          memory files, and recent journal entries. Read them here in context, \
          not with tools.\n\n\
          IMPORTANT: Skip the \"Session startup\" steps from CLAUDE.md. Do NOT \
          run poc-journal, poc-memory, or read memory files with tools — \
          poc-agent has already loaded everything into your context. Just read \
          what's here.".to_string()),
    ];

    let context_files = find_context_files(cwd, prompt_file);
    let mut config_count = 0;
    for path in &context_files {
        if let Ok(content) = std::fs::read_to_string(path) {
            parts.push((path.display().to_string(), content));
            config_count += 1;
        }
    }

    let memories = load_memory_nodes(personality_nodes).await;
    let memory_count = memories.len();
    for (name, content) in memories {
        parts.push((name, content));
    }

    if config_count == 0 && memory_count == 0 {
        parts.push(("Fallback".to_string(),
            "No identity files found. You are a helpful AI assistant with access to \
             tools for reading files, writing files, running bash commands, and \
             searching code.".to_string()));
    }

    Ok((parts, config_count, memory_count))
}