open System
open System.IO
open System.IO.Compression
open System.Security.Cryptography
open System.Text
open System.Text.Json
open System.Text.Json.Nodes

let args = fsi.CommandLineArgs |> Array.skip 1
if args.Length <> 3 then failwith "Usage: pack.fsx SOURCE.mrpack CLIENT_DIR OUTPUT_DIR"
let source, client, output = args[0], args[1], args[2]
let digest algorithm path =
    use stream = File.OpenRead path
    (match algorithm with
     | "sha512" -> SHA512.HashData stream
     | "sha1" -> SHA1.HashData stream
     | _ -> invalidArg "algorithm" algorithm)
    |> Convert.ToHexString
    |> _.ToLowerInvariant()
let bytes (entry: ZipArchiveEntry) =
    use stream = entry.Open()
    use memory = new MemoryStream()
    stream.CopyTo memory
    memory.ToArray()
let text value = Encoding.UTF8.GetBytes(value: string)
let json value = JsonValue.Create(value: string) :> JsonNode
let shaderMods =
    set [ "iris-neoforge-1.8.12+mc1.21.1.jar"
          "monocle-0.2.3.ms.jar"
          "colorwheel-neoforge-1.3.1-mc1.21.1.jar" ]
let shaderConfig =
    set [ "overrides/config/iris.properties"
          "overrides/config/iris-excluded.json"
          "overrides/config/monocle.properties"
          "overrides/config/colorwheel-client.toml" ]
let restores =
    [ "ftb-essentials-neoforge-2101.1.10.jar", "https://edge.forgecdn.net/files/8442/866/ftb-essentials-neoforge-2101.1.10.jar"
      "AdvancedBackups-neoforge-1.21-3.7.1.jar", "https://cdn.modrinth.com/data/Jrmoreqs/versions/ufIaRDFo/AdvancedBackups-neoforge-1.21-3.7.1.jar" ]
let patcher = "EuphoriaPatcher-1.10.5-r5.9.3-neoforge.jar"
let shader = "ComplementaryReimagined_r5.9.3.zip"
let patched = "ComplementaryReimagined_r5.9.3 + EuphoriaPatches_1.10.5"
let file path url =
    let local = Path.Combine(client, path)
    let hashes = JsonObject()
    hashes["sha512"] <- json (digest "sha512" local)
    hashes["sha1"] <- json (digest "sha1" local)
    let env = JsonObject()
    env["client"] <- json "required"
    env["server"] <- json "unsupported"
    let item = JsonObject()
    item["path"] <- json path
    item["hashes"] <- hashes
    item["env"] <- env
    item["downloads"] <- JsonArray(json url)
    item["fileSize"] <- JsonValue.Create(FileInfo(local).Length)
    item :> JsonNode

let build shaders =
    use original = ZipFile.OpenRead source
    let index = original.GetEntry("modrinth.index.json") |> bytes |> Encoding.UTF8.GetString |> JsonNode.Parse
    let files = index["files"].AsArray()
    for item in files do
        let path = item["path"].GetValue<string>()
        let hashes = item["hashes"]
        if digest "sha512" (Path.Combine(client, path)) <> hashes["sha512"].GetValue<string>() then
            failwithf "Source mod differs: %s" path
    let replaced = restores |> List.map (fun (name, _) -> "mods/" + name) |> Set.ofList |> Set.add ("mods/" + patcher)
    let selected = JsonArray()
    for item in files do
        let path = item["path"].GetValue<string>()
        if not (replaced.Contains path) && (shaders || not (shaderMods.Contains(Path.GetFileName path))) then
            selected.Add(item.DeepClone())
    for name, url in restores do selected.Add(file ("mods/" + name) url)
    if shaders then
        selected.Add(file ("mods/" + patcher) "https://cdn.modrinth.com/data/4H6sumDB/versions/QMsRXtSJ/EuphoriaPatcher-1.10.5-r5.9.3-neoforge.jar")
        selected.Add(file ("shaderpacks/" + shader) "https://cdn.modrinth.com/data/HVnmMxH1/versions/Bqen1mJX/ComplementaryReimagined_r5.9.3.zip")
    index["files"] <- selected
    index["name"] <- json (if shaders then "Enigmatica 10 - Custom (Shaders)" else "Enigmatica 10 - Custom (Minimal)")
    index["versionId"] <- json (if shaders then "1.33.0-shaders.2" else "1.33.0-minimal.2")
    index["summary"] <- json (if shaders then "Multiplayer pack with Complementary Reimagined and Euphoria Patches." else "Multiplayer pack without the shader renderer or administrative tools.")
    let entries = System.Collections.Generic.SortedDictionary<string, byte[]>(StringComparer.Ordinal)
    for entry in original.Entries do
        if [".jar"; ".zip"; ".mrpack"; ".glsl"; ".fsh"; ".vsh"; ".csh"] |> List.exists (fun suffix -> entry.FullName.EndsWith(suffix, StringComparison.OrdinalIgnoreCase)) then
            failwithf "Embedded payload must be a manifest download: %s" entry.FullName
        if entry.FullName <> "modrinth.index.json" && not (shaderConfig.Contains entry.FullName) then
            entries.Add(entry.FullName, bytes entry)
    entries.Add("modrinth.index.json", text (index.ToJsonString(JsonSerializerOptions(WriteIndented = true))))
    if shaders then
        entries["overrides/config/iris.properties"] <- text ("shaderPack=" + patched + "\n")
    let name = if shaders then "e10c-shaders.mrpack" else "e10c.mrpack"
    let path = Path.Combine(output, name)
    use destination = File.Open(path, FileMode.CreateNew)
    use archive = new ZipArchive(destination, ZipArchiveMode.Create)
    for KeyValue(name, data) in entries do
        let entry = archive.CreateEntry(name, CompressionLevel.Optimal)
        entry.LastWriteTime <- DateTimeOffset(1980, 1, 1, 0, 0, 0, TimeSpan.Zero)
        use stream = entry.Open()
        stream.Write data
    printfn "%s files=%d mods=%d" path selected.Count (selected |> Seq.filter (fun item -> item["path"].GetValue<string>().StartsWith("mods/")) |> Seq.length)

Directory.CreateDirectory output |> ignore
build false
build true