local fs = require("@lune/fs")
local process = require("@lune/process")
local serde = require("@lune/serde")

export type TreeProperties = {
    Name: never?,
    Parent: never?,
}

export type TreeBase = {
    ["$className"]: string?,
    ["$ignoreUnknownInstances"]: boolean?,
    ["$path"]: string | { optional: string }?,
    ["$properties"]: TreeProperties?,
}

export type TreeNormal = TreeBase & {
    [string]: TreeNormal,
} & ({ ["$className"]: string } | {
    ["$path"]: string | { optional: string },
})

export type TreeService = TreeBase & {
    [string]: TreeNormal,
}

export type DataModelTree = TreeBase & {
    StarterPlayer: (TreeBase & {
        StarterPlayerScripts: TreeService?,
        StarterCharacterScripts: TreeService?,
        [string]: TreeNormal,
    })?,
    [string]: TreeService,
}

export type Tree = (DataModelTree & {
    ["$className"]: "DataModel",
}) | TreeNormal

export type SyncConfig = {
    name: string,
    servePort: number?,
    servePlaceIds: { number }?,
    placeId: number?,
    gameId: number?,
    serveAddress: string?,
    globIgnorePaths: { string }?,
    tree: Tree,
}

local PLATFORM_SEP = if process.os == "windows" then "\\" else "/"

--- Generates a Rojo sync configuration file (`default.project.json`) from a list of
--- input files to be included.

--- ## Errors
--- * The current process lacks permissions to a file
--- * Any I/O error occurs
return function(packageDirectory: string?, files: { string }, options: {
    writeToFile: boolean?,
    force: boolean?,
}): (boolean, string?)
    packageDirectory = packageDirectory or process.cwd
    local syncConfigPath = `{packageDirectory}{PLATFORM_SEP}default.project.json`
    if fs.isFile(syncConfigPath) and not options.force then
        return true, nil
    end

    local syncConfigTree = {} :: Tree

    for _, file in files do
        -- Remove the `.lua` or `.luau` file extension from the file name
        local name = string.gsub(file, ".luau?$", "")

        if name == "init" then
            syncConfigTree["$path"] = name
            continue
        end

        syncConfigTree[name] = {
            ["$path"] = file,
        }
    end

    -- If there isn't a top level path, we mark the entire thing as a Folder
    if not syncConfigTree["$path"] then
        syncConfigTree["$className"] = "Folder"
    end

    -- If the config tree does not include pesde's downloaded roblox dependencies
    -- directory, we add it as an optional one for the future, once dependencies
    -- are installed
    if not syncConfigTree["roblox_packages"] then
        syncConfigTree["roblox_packages"] = {
            ["$path"] = {
                optional = "roblox_packages",
            },
        }
    end

    -- Finally, we serialize the config to a JSON string and optionally write it
    -- to the sync config path
    local serializedConfig = serde.encode("json", { tree = syncConfigTree }, true)
    if options.writeToFile then
        fs.writeFile(syncConfigPath, serializedConfig)
    end

    return true, serializedConfig
end