mod tool_registry;
mod tool_working_set;

use std::sync::Arc;

use anyhow::Result;
use collections::{HashMap, HashSet};
use gpui::Context;
use gpui::{App, Entity, SharedString, Task};
use language::Buffer;
use language_model::LanguageModelRequestMessage;
use project::Project;

pub use crate::tool_registry::*;
pub use crate::tool_working_set::*;

pub fn init(cx: &mut App) {
    ToolRegistry::default_global(cx);
}

#[derive(Debug, PartialEq, Eq, PartialOrd, Ord, Hash, Clone)]
pub enum ToolSource {
    /// A native tool built-in to Zed.
    Native,
    /// A tool provided by a context server.
    ContextServer { id: SharedString },
}

/// A tool that can be used by a language model.
pub trait Tool: 'static + Send + Sync {
    /// Returns the name of the tool.
    fn name(&self) -> String;

    /// Returns the description of the tool.
    fn description(&self) -> String;

    /// Returns the source of the tool.
    fn source(&self) -> ToolSource {
        ToolSource::Native
    }

    /// Returns the JSON schema that describes the tool's input.
    fn input_schema(&self) -> serde_json::Value {
        serde_json::Value::Object(serde_json::Map::default())
    }

    /// Runs the tool with the provided input.
    fn run(
        self: Arc<Self>,
        input: serde_json::Value,
        messages: &[LanguageModelRequestMessage],
        project: Entity<Project>,
        action_log: Entity<ActionLog>,
        cx: &mut App,
    ) -> Task<Result<String>>;
}

/// Tracks actions performed by tools in a thread
#[derive(Debug)]
pub struct ActionLog {
    /// Buffers that user manually added to the context, and whose content has
    /// changed since the model last saw them.
    stale_buffers_in_context: HashSet<Entity<Buffer>>,
    /// Buffers that we want to notify the model about when they change.
    tracked_buffers: HashMap<Entity<Buffer>, TrackedBuffer>,
}

#[derive(Debug, Default)]
struct TrackedBuffer {
    version: clock::Global,
}

impl ActionLog {
    /// Creates a new, empty action log.
    pub fn new() -> Self {
        Self {
            stale_buffers_in_context: HashSet::default(),
            tracked_buffers: HashMap::default(),
        }
    }

    /// Track a buffer as read, so we can notify the model about user edits.
    pub fn buffer_read(&mut self, buffer: Entity<Buffer>, cx: &mut Context<Self>) {
        let tracked_buffer = self.tracked_buffers.entry(buffer.clone()).or_default();
        tracked_buffer.version = buffer.read(cx).version();
    }

    /// Mark a buffer as edited, so we can refresh it in the context
    pub fn buffer_edited(&mut self, buffers: HashSet<Entity<Buffer>>, cx: &mut Context<Self>) {
        for buffer in &buffers {
            let tracked_buffer = self.tracked_buffers.entry(buffer.clone()).or_default();
            tracked_buffer.version = buffer.read(cx).version();
        }

        self.stale_buffers_in_context.extend(buffers);
    }

    /// Iterate over buffers changed since last read or edited by the model
    pub fn stale_buffers<'a>(&'a self, cx: &'a App) -> impl Iterator<Item = &'a Entity<Buffer>> {
        self.tracked_buffers
            .iter()
            .filter(|(buffer, tracked)| tracked.version != buffer.read(cx).version)
            .map(|(buffer, _)| buffer)
    }

    /// Takes and returns the set of buffers pending refresh, clearing internal state.
    pub fn take_stale_buffers_in_context(&mut self) -> HashSet<Entity<Buffer>> {
        std::mem::take(&mut self.stale_buffers_in_context)
    }
}