const std = @import("std");
const langs = @import("lang.zig");
const runners = @import("runner.zig");
const printer = @import("printer.zig");

test "scritcher" {
    _ = @import("lang.zig");
    _ = @import("runner.zig");
}

pub fn doRepl(allocator: *std.mem.Allocator, args_it: var) !void {
    var stdout_file = try std.io.getStdOut();
    const stdout = &stdout_file.outStream().stream;

    const scri_path = try (args_it.next(allocator) orelse @panic("expected scri path"));

    var file = try std.fs.File.openWrite(scri_path);
    defer file.close();

    var out = file.outStream();
    var stream = &out.stream;

    // the thing here is that 'load :0' would load the scri_path, since we
    // now have a 'repl' argument right before it. to counteract that, the
    // initial repl buffer contains 'load :1' instead.

    var cmds = langs.CommandList.init(allocator);
    defer cmds.deinit();

    var loadargs = langs.ArgList.init(allocator);
    defer loadargs.deinit();

    try loadargs.append(":1");

    try cmds.append(langs.Command{
        .command = .Load,
        .args = loadargs,
    });

    // TODO start a runner and keep it hot

    var lang = langs.Lang.init(allocator);
    defer lang.deinit();

    while (true) {
        try stdout.print("> ");

        var buffer = try std.Buffer.init(allocator, ""[0..]);
        var line = std.io.readLine(&buffer) catch |err| {
            if (err == error.EndOfStream) break;
            return err;
        };

        var cmds_parsed = lang.parse(line) catch |err| {
            std.debug.warn("repl: error while parsing: {}\n", err);
            continue;
        };
        try cmds.append(cmds_parsed.at(0));

        lang.reset();

        // TODO save the line to scri_file? or should we have a special `push`
        // to do so?

        try file.seekTo(0);
        try printer.printList(cmds, stream);
    }
}

pub fn main() !void {
    const allocator = std.heap.direct_allocator;

    var lang = langs.Lang.init(allocator);
    defer lang.deinit();

    var runner = runners.Runner.init(allocator);
    defer runner.deinit();

    var args_it = std.process.args();

    // TODO print help

    _ = try (args_it.next(allocator) orelse @panic("expected exe name"));
    const scri_path = try (args_it.next(allocator) orelse @panic("expected scri path"));

    if (std.mem.eql(u8, scri_path, "repl")) {
        return try doRepl(allocator, &args_it);
    }

    var file = try std.fs.File.openRead(scri_path);
    defer file.close();

    // sadly, we read it all into memory. such is life
    const total_bytes = try file.getEndPos();

    var data = try allocator.alloc(u8, total_bytes);
    defer allocator.free(data);
    _ = try file.read(data);

    var cmds = try lang.parse(data);
    defer cmds.deinit();

    try runner.runCommands(cmds, true);
}