const std = @import("std");

const Allocator = std.mem.Allocator;
const Scanner = @import("scanner.zig").Scanner;

pub var hadError = false;

fn run(allocator: *Allocator, data: []u8) !void {
    var stdout_file = try std.io.getStdOut();
    const stdout = &stdout_file.outStream().stream;

    var scanner = try Scanner.init(allocator, data);
    var tokens = try scanner.scanTokens();
    var it = tokens.iterator();

    while (it.next()) |token| {
        switch (token) {
            .Simple => |value| {
                try value.printToken(stdout);
            },
            .Slice => |value| {
                try value.printToken(stdout);
            },
            .Number => |value| {
                try value.printToken(stdout);
            },
        }

        hadError = false;
    }
}

pub fn doError(line: usize, message: []const u8) !void {
    try errorReport(line, "", message);
}

pub fn errorReport(line: usize, where: []const u8, message: []const u8) !void {
    var stdout_file = try std.io.getStdOut();
    const stdout = &stdout_file.outStream().stream;

    try stdout.print("[line {}] Error {}: {}\n", line, where, message);
    hadError = true;
}

fn runFile(allocator: *Allocator, path: []const u8) !void {
    var lox_file = try std.fs.File.openRead(path);
    defer lox_file.close();

    const total_bytes = try lox_file.getEndPos();
    var slice = try allocator.alloc(u8, total_bytes);
    _ = try lox_file.read(slice);

    try run(allocator, slice);
    if (hadError) std.os.exit(65);
}

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

    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) return;
            return err;
        };

        try run(allocator, line);
    }
}

pub fn main() anyerror!void {
    var da = std.heap.DirectAllocator.init();
    var arena = std.heap.ArenaAllocator.init(&da.allocator);
    var allocator = &arena.allocator;

    var args_it = std.process.args();

    const jorts_arg0 = try (args_it.next(allocator) orelse {
        // if you ever reach this, tell me what is your os lmao
        unreachable;
    });

    const lox_path = try (args_it.next(allocator) orelse {
        try runPrompt(allocator);
        return;
    });

    try runFile(allocator, lox_path);
}