const std = @import("std");

pub fn main() !void {
    var arena = std.heap.ArenaAllocator.init(std.heap.page_allocator);
    defer arena.deinit();
    const allocator = arena.allocator();

    // Get output filename from build system
    const args = try std.process.argsAlloc(allocator);
    if (args.len < 3) @panic("Missing output filename");
    const out_path = args[1];

    // Generate a startup module function that invokes
    // startup module for each zig function
    // and generates an api
    var writer = std.ArrayList(u8){};
    const moduleList = args[2..];

    for (moduleList) |mod| {
        try writer.print(allocator, "pub const {s} = @import(\"{s}\").module;\n", .{ mod, mod });
    }

    try writer.print(allocator, "pub const moduleList:[]const []const u8 = &.{{\n", .{});
    for (moduleList) |mod| {
        try writer.print(allocator, "\"{s}\",\n", .{mod});
    }
    try writer.print(allocator, "}};\n", .{});

    try writer.print(allocator,
        \\var shutdownList: std.ArrayListUnmanaged(*const fn (std.mem.Allocator) void) = .{{}};
        \\var shutdownModuleNames: std.ArrayListUnmanaged([]const u8) = .{{}};
        \\
        \\ pub const NwArgs = struct {{
        \\     useGPA: bool = false, // slower zig based memory allocator, provides detailed tracking of leaks and memory violations
        \\     vulkanValidation: bool = true,
        \\     fastTest: bool = false,
        \\     dmt: bool = false, // detailed memory tracking, implements a timeline for tracking all memory allocations
        \\     fatDump: bool = false, // takes a full fat minidump on crash, very large files are produced
        \\ }};
        \\ 
        \\ pub fn getArgs() !NwArgs {{
        \\     const a = try core.ParseArgs(NwArgs);
        \\ 
        \\     return a;
        \\ }}
    , .{});
    try writer.print(allocator, "pub fn start_modules_(spec: *core.SpecVariantMap, maybeArgs: ?NwArgs, allocator: std.mem.Allocator) !void {{", .{});

    try writer.print(allocator,
        \\
        \\ var z = core.tracy.ZoneN(@src(), "Starting all Modules");
        \\ defer z.End();
        \\ inline for (moduleList) |feature| {{
        \\     if (@hasDecl(@This(), feature)) {{
        \\         const Struct = @field(@This(), feature);
        \\         if (core.isModuleEnabled(Struct.Module, spec)) {{
        \\             var z1 = core.tracy.ZoneN(@src(), @ptrCast("Initializing Module"));
        \\             defer z1.End();
        \\             core.tracy.Message(Struct.Module.name);
        \\             if (maybeArgs) |args| {{
        \\                 try Struct.start_module(spec, args, allocator);
        \\             }} else {{
        \\                 try Struct.start_module(spec, NwArgs{{}}, allocator);
        \\             }}
        \\             if(core.MemoryTracker.MTGet()) |_|
        \\             {{
        \\                core.MemoryTracker.MTPrintStatsDelta();
        \\             }}
        \\             try shutdownList.append(allocator, Struct.shutdown_module);
        \\             try shutdownModuleNames.append(allocator, feature);
        \\             core.engine_logs("module started >>>> " ++ feature ++ " <<<<");
        \\         }}
        \\     }}
        \\ }} }}
        \\pub fn start_modules(spec: *core.SpecVariantMap, maybeArgs: ?NwArgs, allocator: std.mem.Allocator) bool {{ start_modules_(spec, maybeArgs, allocator) catch return false; return true;}}
        \\
        \\ pub fn shutdown_modules(allocator: std.mem.Allocator) void {{
        \\     var i: isize = @intCast(shutdownList.items.len - 1);
        \\     while (i >= 0) : (i -= 1) {{
        \\         core.engine_log("module shutting down >>>> {{s}} <<<<", .{{shutdownModuleNames.items[@intCast(i)]}});
        \\         shutdownList.items[@intCast(i)](allocator);
        \\     }}
        \\     shutdownList.deinit(allocator);
        \\     shutdownModuleNames.deinit(allocator);
        \\ }}
        \\
    , .{});

    _ = try writer.appendSlice(allocator,
        \\ pub fn startEngine(vtable: *core.EngineObjectVTable, spec: *core.SpecVariantMap) bool {
        \\     const args = getArgs() catch return false;
        \\ 
        \\     var backingAllocator: std.mem.Allocator = std.heap.smp_allocator;
        \\     var gpa: std.heap.GeneralPurposeAllocator(.{
        \\         .stack_trace_frames = 20,
        \\     }) = .{};
        \\ 
        \\     defer {
        \\         const cleanupStatus = gpa.deinit();
        \\         if (cleanupStatus == .leak) {
        \\             std.debug.print("gpa cleanup leaked memory\n", .{});
        \\         }
        \\     }
        \\ 
        \\     if (spec.get("useGPA")) |arg| {
        \\         if (arg.boolean == true) {
        \\             backingAllocator = gpa.allocator();
        \\         }
        \\     }
        \\ 
        \\     const memory = core.MemoryTracker;
        \\     memory.MTSetup(backingAllocator, .{ .timeline = args.dmt });
        \\     defer memory.MTShutdown();
        \\ 
        \\     var tracker = memory.MTGet().?;
        \\     const allocator = tracker.allocator();
        \\
        \\     _ = core.createNameRegistry(allocator) catch return false;
        \\     core.maybeInitPackerFs(allocator) catch return false;
        \\      
        \\     if(core.BuildOption("static_build"))
        \\     {
        \\          core.engine_log("static build, using embedded shaders", .{});
        \\          const loader = @import("staticShaderLoader");
        \\          loader.installStaticResources() catch return false;
        \\     }
        \\ 
        \\     if (!start_modules(spec, args, allocator)) return false;
        \\     defer shutdown_modules(allocator);
        \\ 
        \\     run_everything_vtable(vtable) catch return false;
        \\ 
        \\     return true;
        \\ }
        \\
        \\
        \\ pub const loadDynamicModules = @import("loadDynamics").loadDynamicModules;
        \\
        \\   pub fn run_everything_vtable(gameVtable: *core.EngineObjectVTable) !void {
        \\       core.engine_logs("creating Game context");
        \\   
        \\       //_ = try core.createObject(GameContext, .{});
        \\       _ = try core.createObjectVTable(gameVtable, .{});
        \\   
        \\       core.engine_logs("calling gEngine.run");
        \\   
        \\       try core.getEngine().run();
        \\   
        \\       while (!core.getEngine().exitFinished()) {
        \\           const z = core.tracy.ZoneN(@src(), "shutdown poll");
        \\           z.End();
        \\       }
        \\   }
        \\
        \\   pub fn getSpec(comptime name:[]const u8) !core.SpecVariantMap {
        \\      return try core.createSpecVariant(.{
        \\          .useGPA = true,
        \\          .name = name,
    );

    for (moduleList) |mod| {
        try writer.print(allocator, ".{s} = true,\n", .{mod});
    }

    try writer.print(allocator, "}},  std.heap.smp_allocator); }}\n", .{});

    try writer.print(allocator, "const std = @import(\"std\");\n\n", .{});

    // Write to specified output file
    // Open or create the file for writing (overwrites if it exists)
    const file = try std.fs.cwd().createFile(out_path, .{});
    defer file.close();

    try writer.append(allocator, 0);

    var ast = try std.zig.Ast.parse(allocator, @as([:0]const u8, @ptrCast(writer.items[0 .. writer.items.len - 1])), .zig);
    // std.debug.print("output=\n{s}", .{content.items[0 .. content.items.len - 1]});
    defer ast.deinit(allocator);
    const out = try ast.renderAlloc(allocator);

    // Write the content to the file
    try file.writeAll(out);
}