namespace Rezoom.SQL.Provider

open System

open System.Collections.Generic

open System.IO

open Rezoom.SQL.Compiler

type private UserModelCache() as this =

let watchers = Dictionary()

let cache = Dictionary()

let invalidated = Event<EventHandler, EventArgs>()

let addWatcher path invalidateKey =

let succ, watcher = watchers.TryGetValue(path)

let watcher =

if succ then watcher else

let watcher = new Watcher(path)

watcher.Invalidated.Add(fun _ -> invalidated.Trigger(this, EventArgs.Empty))

watchers.Add(path, watcher)

watcher

watcher.Invalidating.Add(fun _ -> ignore <| cache.Remove(invalidateKey)) // remove from cache on changes

[<CLIEvent>]

member __.Invalidated = invalidated.Publish

member this.Load(resolutionFolder, modelPath) =

let key = (resolutionFolder, modelPath)

let succ, cachedModel = cache.TryGetValue(key)

if succ then cachedModel else

let model = UserModel.Load(resolutionFolder, modelPath)

cache.[key] <- model

addWatcher model.ConfigDirectory key

addWatcher model.MigrationsDirectory key

model

member this.Dispose() =

for KeyValue(_, w) in watchers do

w.Dispose()

watchers.Clear()

interface IDisposable with

member this.Dispose() = this.Dispose()