// tools/memory.rs — Native memory graph operations
//
// Direct library calls into the store — no subprocess spawning.
// One function per tool for use in the Tool registry.

use anyhow::{Context, Result};
use serde_json::json;

use crate::hippocampus::memory::MemoryNode;
use crate::store::StoreView;
use super::ToolDef;
use crate::store::Store;

// ── Helpers ────────────────────────────────────────────────────

fn get_str<'a>(args: &'a serde_json::Value, name: &'a str) -> Result<&'a str> {
    args.get(name).and_then(|v| v.as_str()).context(format!("{} is required", name))
}

fn get_f64(args: &serde_json::Value, name: &str) -> Result<f64> {
    args.get(name).and_then(|v| v.as_f64()).context(format!("{} is required", name))
}

fn load_store() -> Result<Store> {
    Store::load().map_err(|e| anyhow::anyhow!("{}", e))
}

fn provenance() -> &'static str { "manual" }

// ── Definitions ────────────────────────────────────────────────

pub fn memory_tools() -> Vec<super::Tool> {
    use super::Tool;
    vec![
        Tool { def: render_def(),     handler: |_a, v| Box::pin(async move { render(&v) }) },
        Tool { def: write_def(),      handler: |_a, v| Box::pin(async move { write(&v) }) },
        Tool { def: search_def(),     handler: |_a, v| Box::pin(async move { search(&v) }) },
        Tool { def: links_def(),      handler: |_a, v| Box::pin(async move { links(&v) }) },
        Tool { def: link_set_def(),   handler: |_a, v| Box::pin(async move { link_set(&v) }) },
        Tool { def: link_add_def(),   handler: |_a, v| Box::pin(async move { link_add(&v) }) },
        Tool { def: used_def(),       handler: |_a, v| Box::pin(async move { used(&v) }) },
        Tool { def: weight_set_def(), handler: |_a, v| Box::pin(async move { weight_set(&v) }) },
        Tool { def: rename_def(),     handler: |_a, v| Box::pin(async move { rename(&v) }) },
        Tool { def: supersede_def(),  handler: |_a, v| Box::pin(async move { supersede(&v) }) },
        Tool { def: query_def(),      handler: |_a, v| Box::pin(async move { query(&v) }) },
        Tool { def: output_def(),     handler: |_a, v| Box::pin(async move { output(&v) }) },
    ]
}

pub fn journal_tools() -> Vec<super::Tool> {
    use super::Tool;
    vec![
        Tool { def: journal_tail_def(),   handler: |_a, v| Box::pin(async move { journal_tail(&v) }) },
        Tool { def: journal_new_def(),    handler: |_a, v| Box::pin(async move { journal_new(&v) }) },
        Tool { def: journal_update_def(), handler: |_a, v| Box::pin(async move { journal_update(&v) }) },
    ]
}

// ── Memory tools ───────────────────────────────────────────────

fn render_def() -> ToolDef {
    ToolDef::new("memory_render",
        "Read a memory node's content and links.",
        json!({"type":"object","properties":{"key":{"type":"string","description":"Node key"}},"required":["key"]}))
}

fn render(args: &serde_json::Value) -> Result<String> {
    let key = get_str(args, "key")?;
    Ok(MemoryNode::load(key)
        .ok_or_else(|| anyhow::anyhow!("node not found: {}", key))?
        .render())
}

fn write_def() -> ToolDef {
    ToolDef::new("memory_write",
        "Create or update a memory node.",
        json!({"type":"object","properties":{"key":{"type":"string","description":"Node key"},"content":{"type":"string","description":"Full content (markdown)"}},"required":["key","content"]}))
}

fn write(args: &serde_json::Value) -> Result<String> {
    let key = get_str(args, "key")?;
    let content = get_str(args, "content")?;
    let mut store = load_store()?;
    let result = store.upsert_provenance(key, content, provenance())
        .map_err(|e| anyhow::anyhow!("{}", e))?;
    store.save().map_err(|e| anyhow::anyhow!("{}", e))?;
    Ok(format!("{} '{}'", result, key))
}

fn search_def() -> ToolDef {
    ToolDef::new("memory_search",
        "Search the memory graph via spreading activation. Give 2-4 seed \
         node keys related to what you're looking for. Returns nodes ranked \
         by how strongly they connect to your seeds — bridging nodes score \
         highest. This finds conceptual connections, not just keyword matches.",
        json!({"type":"object","properties":{"keys":{"type":"array","items":{"type":"string"},"description":"Seed node keys to activate from"}},"required":["keys"]}))
}

fn search(args: &serde_json::Value) -> Result<String> {
    let keys: Vec<String> = args.get("keys")
        .and_then(|v| v.as_array())
        .map(|arr| arr.iter().filter_map(|v| v.as_str().map(String::from)).collect())
        .unwrap_or_default();
    if keys.is_empty() {
        anyhow::bail!("memory_search requires at least one seed key");
    }
    let store = load_store()?;
    let graph = crate::graph::build_graph_fast(&store);
    let params = store.params();
    let seeds: Vec<(String, f64)> = keys.iter()
        .filter_map(|k| {
            let resolved = store.resolve_key(k).ok()?;
            Some((resolved, 1.0))
        })
        .collect();
    if seeds.is_empty() {
        anyhow::bail!("no valid seed keys found");
    }
    let seed_set: std::collections::HashSet<&str> = seeds.iter()
        .map(|(k, _)| k.as_str()).collect();
    let results = crate::search::spreading_activation(
        &seeds, &graph, &store,
        params.max_hops, params.edge_decay, params.min_activation,
    );
    Ok(results.iter()
        .filter(|(k, _)| !seed_set.contains(k.as_str()))
        .take(20)
        .map(|(key, score)| format!("  {:.2}  {}", score, key))
        .collect::<Vec<_>>().join("\n"))
}

fn links_def() -> ToolDef {
    ToolDef::new("memory_links",
        "Show a node's neighbors with link strengths.",
        json!({"type":"object","properties":{"key":{"type":"string","description":"Node key"}},"required":["key"]}))
}

fn links(args: &serde_json::Value) -> Result<String> {
    let key = get_str(args, "key")?;
    let node = MemoryNode::load(key)
        .ok_or_else(|| anyhow::anyhow!("node not found: {}", key))?;
    let mut out = format!("Neighbors of '{}':\n", key);
    for (target, strength, is_new) in &node.links {
        let tag = if *is_new { " (new)" } else { "" };
        out.push_str(&format!("  ({:.2}) {}{}\n", strength, target, tag));
    }
    Ok(out)
}

fn link_set_def() -> ToolDef {
    ToolDef::new("memory_link_set",
        "Set link strength between two nodes.",
        json!({"type":"object","properties":{"source":{"type":"string"},"target":{"type":"string"},"strength":{"type":"number","description":"0.01 to 1.0"}},"required":["source","target","strength"]}))
}

fn link_set(args: &serde_json::Value) -> Result<String> {
    let mut store = load_store()?;
    let s = store.resolve_key(get_str(args, "source")?).map_err(|e| anyhow::anyhow!("{}", e))?;
    let t = store.resolve_key(get_str(args, "target")?).map_err(|e| anyhow::anyhow!("{}", e))?;
    let strength = get_f64(args, "strength")? as f32;
    let old = store.set_link_strength(&s, &t, strength).map_err(|e| anyhow::anyhow!("{}", e))?;
    store.save().map_err(|e| anyhow::anyhow!("{}", e))?;
    Ok(format!("{} ↔ {} strength {:.2} → {:.2}", s, t, old, strength))
}

fn link_add_def() -> ToolDef {
    ToolDef::new("memory_link_add",
        "Add a new link between two nodes.",
        json!({"type":"object","properties":{"source":{"type":"string"},"target":{"type":"string"}},"required":["source","target"]}))
}

fn link_add(args: &serde_json::Value) -> Result<String> {
    let mut store = load_store()?;
    let s = store.resolve_key(get_str(args, "source")?).map_err(|e| anyhow::anyhow!("{}", e))?;
    let t = store.resolve_key(get_str(args, "target")?).map_err(|e| anyhow::anyhow!("{}", e))?;
    let strength = store.add_link(&s, &t, provenance()).map_err(|e| anyhow::anyhow!("{}", e))?;
    store.save().map_err(|e| anyhow::anyhow!("{}", e))?;
    Ok(format!("linked {} → {} (strength={:.2})", s, t, strength))
}

fn used_def() -> ToolDef {
    ToolDef::new("memory_used",
        "Mark a node as useful (boosts weight).",
        json!({"type":"object","properties":{"key":{"type":"string","description":"Node key"}},"required":["key"]}))
}

fn used(args: &serde_json::Value) -> Result<String> {
    let key = get_str(args, "key")?;
    let mut store = load_store()?;
    if !store.nodes.contains_key(key) {
        anyhow::bail!("node not found: {}", key);
    }
    store.mark_used(key);
    store.save().map_err(|e| anyhow::anyhow!("{}", e))?;
    Ok(format!("marked {} as used", key))
}

fn weight_set_def() -> ToolDef {
    ToolDef::new("memory_weight_set",
        "Set a node's weight directly (0.01 to 1.0).",
        json!({"type":"object","properties":{"key":{"type":"string"},"weight":{"type":"number","description":"0.01 to 1.0"}},"required":["key","weight"]}))
}

fn weight_set(args: &serde_json::Value) -> Result<String> {
    let mut store = load_store()?;
    let key = store.resolve_key(get_str(args, "key")?).map_err(|e| anyhow::anyhow!("{}", e))?;
    let weight = get_f64(args, "weight")? as f32;
    let (old, new) = store.set_weight(&key, weight).map_err(|e| anyhow::anyhow!("{}", e))?;
    store.save().map_err(|e| anyhow::anyhow!("{}", e))?;
    Ok(format!("weight {} {:.2} → {:.2}", key, old, new))
}

fn rename_def() -> ToolDef {
    ToolDef::new("memory_rename",
        "Rename a node key in place. Same content, same links, new key.",
        json!({"type":"object","properties":{"old_key":{"type":"string"},"new_key":{"type":"string"}},"required":["old_key","new_key"]}))
}

fn rename(args: &serde_json::Value) -> Result<String> {
    let old_key = get_str(args, "old_key")?;
    let new_key = get_str(args, "new_key")?;
    let mut store = load_store()?;
    let resolved = store.resolve_key(old_key).map_err(|e| anyhow::anyhow!("{}", e))?;
    store.rename_node(&resolved, new_key).map_err(|e| anyhow::anyhow!("{}", e))?;
    store.save().map_err(|e| anyhow::anyhow!("{}", e))?;
    Ok(format!("Renamed '{}' → '{}'", resolved, new_key))
}

fn supersede_def() -> ToolDef {
    ToolDef::new("memory_supersede",
        "Mark a node as superseded by another (sets weight to 0.01).",
        json!({"type":"object","properties":{"old_key":{"type":"string"},"new_key":{"type":"string"},"reason":{"type":"string"}},"required":["old_key","new_key"]}))
}

fn supersede(args: &serde_json::Value) -> Result<String> {
    let old_key = get_str(args, "old_key")?;
    let new_key = get_str(args, "new_key")?;
    let reason = args.get("reason").and_then(|v| v.as_str()).unwrap_or("superseded");
    let mut store = load_store()?;
    let content = store.nodes.get(old_key)
        .map(|n| n.content.clone())
        .ok_or_else(|| anyhow::anyhow!("node not found: {}", old_key))?;
    let notice = format!("**SUPERSEDED** by `{}` — {}\n\n---\n\n{}",
        new_key, reason, content.trim());
    store.upsert_provenance(old_key, &notice, provenance())
        .map_err(|e| anyhow::anyhow!("{}", e))?;
    store.set_weight(old_key, 0.01).map_err(|e| anyhow::anyhow!("{}", e))?;
    store.save().map_err(|e| anyhow::anyhow!("{}", e))?;
    Ok(format!("superseded {} → {} ({})", old_key, new_key, reason))
}

fn query_def() -> ToolDef {
    ToolDef::new("memory_query",
        "Run a structured query against the memory graph. Supports filtering, \
         sorting, field selection. Examples: \"degree > 10 | sort weight | limit 5\", \
         \"neighbors('identity') | select strength\", \"key ~ 'journal.*' | count\"",
        json!({"type":"object","properties":{"query":{"type":"string","description":"Query expression"}},"required":["query"]}))
}

fn query(args: &serde_json::Value) -> Result<String> {
    let query_str = get_str(args, "query")?;
    let store = load_store()?;
    let graph = store.build_graph();
    crate::query_parser::query_to_string(&store, &graph, query_str)
        .map_err(|e| anyhow::anyhow!("{}", e))
}

fn output_def() -> ToolDef {
    ToolDef::new("output",
        "Produce a named output value. Use this to pass structured results \
         between steps — subsequent prompts can see these in the conversation history.",
        json!({"type":"object","properties":{
            "key":{"type":"string","description":"Output name (e.g. 'relevant_memories')"},
            "value":{"type":"string","description":"Output value"}
        },"required":["key","value"]}))
}

fn output(args: &serde_json::Value) -> Result<String> {
    let key = get_str(args, "key")?;
    if key.starts_with("pid-") || key.contains('/') || key.contains("..") {
        anyhow::bail!("invalid output key: {}", key);
    }
    let value = get_str(args, "value")?;
    let dir = std::env::var("POC_AGENT_OUTPUT_DIR")
        .map_err(|_| anyhow::anyhow!("no output directory set"))?;
    let path = std::path::Path::new(&dir).join(key);
    std::fs::write(&path, value)
        .with_context(|| format!("writing output {}", path.display()))?;
    Ok(format!("{}: {}", key, value))
}

// ── Journal tools ──────────────────────────────────────────────

fn journal_tail_def() -> ToolDef {
    ToolDef::new("journal_tail",
        "Read the last N journal entries (default 1).",
        json!({"type":"object","properties":{
            "count":{"type":"integer","description":"Number of entries (default 1)"}
        }}))
}

fn journal_tail(args: &serde_json::Value) -> Result<String> {
    let count = args.get("count").and_then(|v| v.as_u64()).unwrap_or(1) as usize;
    let store = load_store()?;
    let mut entries: Vec<&crate::store::Node> = store.nodes.values()
        .filter(|n| n.node_type == crate::store::NodeType::EpisodicSession)
        .collect();
    entries.sort_by_key(|n| n.created_at);
    let start = entries.len().saturating_sub(count);
    if entries[start..].is_empty() {
        Ok("(no journal entries)".into())
    } else {
        Ok(entries[start..].iter()
            .map(|n| n.content.as_str())
            .collect::<Vec<_>>()
            .join("\n\n"))
    }
}

fn journal_new_def() -> ToolDef {
    ToolDef::new("journal_new",
        "Start a new journal entry.",
        json!({"type":"object","properties":{
            "name":{"type":"string","description":"Short node name (becomes the key)"},
            "title":{"type":"string","description":"Descriptive title for the heading"},
            "body":{"type":"string","description":"Entry body (2-3 paragraphs)"}
        },"required":["name","title","body"]}))
}

fn journal_new(args: &serde_json::Value) -> Result<String> {
    let name = get_str(args, "name")?;
    let title = get_str(args, "title")?;
    let body = get_str(args, "body")?;
    let ts = chrono::Local::now().format("%Y-%m-%dT%H:%M");
    let content = format!("## {} — {}\n\n{}", ts, title, body);

    let base_key: String = name.split_whitespace()
        .map(|w| w.to_lowercase()
            .chars().filter(|c| c.is_alphanumeric() || *c == '-')
            .collect::<String>())
        .filter(|s| !s.is_empty())
        .collect::<Vec<_>>()
        .join("-");
    let base_key = if base_key.len() > 80 { &base_key[..80] } else { base_key.as_str() };

    let mut store = load_store()?;
    let key = if store.nodes.contains_key(base_key) {
        let mut n = 2;
        loop {
            let candidate = format!("{}-{}", base_key, n);
            if !store.nodes.contains_key(&candidate) { break candidate; }
            n += 1;
        }
    } else {
        base_key.to_string()
    };
    let mut node = crate::store::new_node(&key, &content);
    node.node_type = crate::store::NodeType::EpisodicSession;
    node.provenance = provenance().to_string();
    store.upsert_node(node).map_err(|e| anyhow::anyhow!("{}", e))?;
    store.save().map_err(|e| anyhow::anyhow!("{}", e))?;
    let word_count = body.split_whitespace().count();
    Ok(format!("New entry '{}' ({} words)", title, word_count))
}

fn journal_update_def() -> ToolDef {
    ToolDef::new("journal_update",
        "Append text to the most recent journal entry (same thread continuing).",
        json!({"type":"object","properties":{
            "body":{"type":"string","description":"Text to append to the last entry"}
        },"required":["body"]}))
}

fn journal_update(args: &serde_json::Value) -> Result<String> {
    let body = get_str(args, "body")?;
    let mut store = load_store()?;
    let latest_key = store.nodes.values()
        .filter(|n| n.node_type == crate::store::NodeType::EpisodicSession)
        .max_by_key(|n| n.created_at)
        .map(|n| n.key.clone());
    let Some(key) = latest_key else {
        anyhow::bail!("no journal entry to update — use journal_new first");
    };
    let existing = store.nodes.get(&key).unwrap().content.clone();
    let new_content = format!("{}\n\n{}", existing.trim_end(), body);
    store.upsert_provenance(&key, &new_content, provenance())
        .map_err(|e| anyhow::anyhow!("{}", e))?;
    store.save().map_err(|e| anyhow::anyhow!("{}", e))?;
    let word_count = body.split_whitespace().count();
    Ok(format!("Updated last entry (+{} words)", word_count))
}