--- Database module for screw.nvim collaboration
---
--- This module handles database connections and operations for real-time
--- collaboration features. Supports RethinkDB for real-time updates.
---

local utils = require("screw.utils")

local M = {}

--- Create a new database connection
---@param config table Collaboration configuration
---@return table Database instance
function M.new(config)
  local db = {}

  db.config = config
  db.connected = false
  db.connection = nil
  db.change_listeners = {}

  --- Connect to the database
  ---@return boolean Success status
  function db:connect()
    -- Parse database URL
    local url = self.config.database_url
    if not url then
      utils.error("Database URL not configured")
      return false
    end

    -- For now, this is a placeholder implementation
    -- Real RethinkDB integration would require additional dependencies
    utils.warn("RethinkDB integration not fully implemented - using mock connection")

    -- Mock connection for development
    self.connected = true
    self.connection = {
      url = url,
      mock = true,
    }

    return true
  end

  --- Disconnect from the database
  function db:disconnect()
    if self.connection then
      -- TODO: Close actual RethinkDB connection
      self.connection = nil
    end
    self.connected = false
  end

  --- Check if connected to database
  ---@return boolean
  function db:is_connected()
    return self.connected
  end

  --- Broadcast a note change to other users
  ---@param change table Change data
  ---@return boolean Success status
  function db:broadcast_change(change)
    if not self.connected then
      return false
    end

    -- TODO: Implement actual RethinkDB broadcast
    -- For now, just store the change locally
    if not self.pending_changes then
      self.pending_changes = {}
    end

    table.insert(self.pending_changes, change)
    return true
  end

  --- Get pending changes from other users
  ---@return table[] Changes
  function db:get_changes()
    if not self.connected then
      return {}
    end

    -- TODO: Implement actual RethinkDB change feed
    -- For now, return empty changes
    return {}
  end

  --- Store a note in the database
  ---@param note ScrewNote
  ---@return boolean Success status
  function db:store_note(note)
    if not self.connected then
      return false
    end

    -- TODO: Implement actual RethinkDB storage
    return true
  end

  --- Retrieve notes from the database
  ---@param filter table? Filter criteria
  ---@return ScrewNote[] Notes
  function db:get_notes(filter)
    if not self.connected then
      return {}
    end

    -- TODO: Implement actual RethinkDB retrieval
    return {}
  end

  --- Delete a note from the database
  ---@param note_id string
  ---@return boolean Success status
  function db:delete_note(note_id)
    if not self.connected then
      return false
    end

    -- TODO: Implement actual RethinkDB deletion
    return true
  end

  --- Set up real-time change feeds
  function db:setup_change_feeds()
    if not self.connected then
      return
    end

    -- TODO: Implement RethinkDB change feeds
    -- This would listen for changes in real-time and call callbacks
  end

  --- Add a change listener
  ---@param callback function
  function db:add_change_listener(callback)
    table.insert(self.change_listeners, callback)
  end

  --- Remove a change listener
  ---@param callback function
  function db:remove_change_listener(callback)
    for i, listener in ipairs(self.change_listeners) do
      if listener == callback then
        table.remove(self.change_listeners, i)
        break
      end
    end
  end

  --- Notify all change listeners
  ---@param changes table[]
  function db:notify_listeners(changes)
    for _, callback in ipairs(self.change_listeners) do
      pcall(callback, changes)
    end
  end

  --- Get database statistics
  ---@return table
  function db:get_stats()
    return {
      connected = self.connected,
      url = self.config.database_url,
      pending_changes = self.pending_changes and #self.pending_changes or 0,
      listeners = #self.change_listeners,
      mock_mode = self.connection and self.connection.mock or false,
    }
  end

  return db
end

--- Create RethinkDB table schema (called during setup)
---@param connection table RethinkDB connection
function M.create_schema(connection)
  -- TODO: Implement RethinkDB schema creation
  -- This would create tables for notes, changes, and user presence
  local schema = {
    tables = {
      "notes",
      "changes",
      "user_presence",
      "projects",
    },
    indexes = {
      notes = { "file_path", "line_number", "author", "timestamp" },
      changes = { "timestamp", "session_id", "note_id" },
      user_presence = { "user_id", "last_seen" },
    },
  }

  return schema
end

return M
