const std = @import("std");
const builtin = @import("builtin");
const eql = @import("std").mem.eql;

const stdout = std.io.getStdOut().writer();
const stdin = std.io.getStdIn().reader();

pub fn main() !void {
    // Read the first argument to determine the subcommand
    const allocator = std.heap.page_allocator;
    var args = try std.process.argsWithAllocator(allocator);
    defer args.deinit();

    _ = args.next(); // Skip the first argument, which is the program name

    const firstArg = args.next() orelse {
        try stdout.print("No subcommand provided\n", .{});
        return;
    };

    if (eql(u8, firstArg, "list")) {
        try listEntries();
    } else if (eql(u8, firstArg, "create")) {
        try createNewEntry();
    } else {
        try stdout.print("Unknown subcommand: {s}\n", .{firstArg});
    }
}

fn createNewEntry() !void {
    // Open the file in append mode
    const file = try std.fs.cwd().openFile("entries.log.gmi", .{ .mode = .read_write });
    defer file.close();
    try file.seekFromEnd(0);

    //const date = try std.time.Time.nowUTC().format("yyyy-MM-dd HH:mm UTC");
    const es = std.time.epoch.EpochSeconds{ .secs = @intCast(std.time.timestamp()) };
    const ed = std.time.epoch.EpochDay{ .day = es.getEpochDay().day };
    var buf2: [256]u8 = undefined;
    const date = try std.fmt.bufPrint(&buf2, "## {d}-{d:0>2}-{d:0>2} {d:0>2}:{d:0>2} UTC\n", .{
        ed.calculateYearDay().year,
        std.time.epoch.YearAndDay.calculateMonthDay(ed.calculateYearDay()).month.numeric(),
        std.time.epoch.YearAndDay.calculateMonthDay(ed.calculateYearDay()).day_index,
        es.getDaySeconds().getHoursIntoDay(),
        es.getDaySeconds().getMinutesIntoHour(),});

    // Read the input content from STDIN and append it to the file
    var buf: [1024]u8 = undefined;
    while (try stdin.readUntilDelimiterOrEof(&buf, '\n')) |line| {
        try file.writeAll("\n");
        try file.writeAll(date);
        try file.writeAll(line);
        try file.writeAll("\n");
    }

    // Print some success message and the back link to STDOUT
    try stdout.print("Entry added successfully\n", .{});
    try stdout.print("=> / Back to the log entries", .{});
}

fn listEntries() !void {
    const file = try std.fs.cwd().openFile("entries.log.gmi", .{});
    defer file.close();

    var bufReader = std.io.bufferedReader(file.reader());
    var inStream = bufReader.reader();

    var buf: [1024]u8 = undefined;
    while (try inStream.readUntilDelimiterOrEof(&buf, '\n')) |line| {
        try stdout.print("{s}\n", .{ line });
    }
}