//! Demo mail: the labels and threads parcel shows until it syncs with
//! Gmail, ages counted back from when they load.

const std = @import("std");
const Contacts = @import("Contacts.zig");
const Mailbox = @import("Mailbox.zig");
const cards = @import("cards.zig");
const ascii = std.ascii;
const mem = std.mem;
const testing = std.testing;
const Allocator = std.mem.Allocator;
const Io = std.Io;
const Rgb = Mailbox.Rgb;
const Writer = Io.Writer;

/// The labels the threads use: Gmail's system ones, named as Mailbox
/// names them, then the user's.
const L = enum {
    inbox,
    starred,
    sent,
    drafts,
    spam,
    trash,
    work,
    hiring,
    family,
    receipts,
    travel,
    newsletters,
    waiting,
    someday,
};

/// The user's labels: which, Gmail id, name, and colour as 0xRRGGBB.
const user_labels = [_]struct { L, []const u8, []const u8, u24 }{
    .{ .work, "Label_1", "Work", 0x2563eb },
    .{ .hiring, "Label_2", "Work/Hiring", 0x7c3aed },
    .{ .family, "Label_3", "Family", 0x16a34a },
    .{ .receipts, "Label_4", "Receipts", 0xea580c },
    .{ .travel, "Label_5", "Travel", 0x0891b2 },
    .{ .newsletters, "Label_6", "Newsletters", 0xdb2777 },
    .{ .waiting, "Label_7", "Waiting", 0xca8a04 },
    .{ .someday, "Label_8", "Someday", 0x64748b },
};

const Sample = struct {
    from: []const u8,
    subject: []const u8,
    snippet: []const u8,
    minutes_ago: u32,
    messages: u8,
    labels: []const L,
    unread: bool,
};

const hour = 60;
const day = 24 * hour;

fn t(
    from: []const u8,
    subject: []const u8,
    snippet: []const u8,
    minutes_ago: u32,
    messages: u8,
    labels: []const L,
    unread: bool,
) Sample {
    return .{
        .from = from,
        .subject = subject,
        .snippet = snippet,
        .minutes_ago = minutes_ago,
        .messages = messages,
        .labels = labels,
        .unread = unread,
    };
}

/// Adds the labels and threads to `mail`, dated back from `now`, in
/// seconds since the epoch.
/// Made-up messages for a sample thread, so the reader has something to
/// show without Gmail: its people in turn, three hours apart, the newest
/// saying the snippet over a quote of the one before.
pub fn conversation(arena: Allocator, thread: *const Mailbox.Thread) ![]const Mailbox.Message {
    var names: std.ArrayList([]const u8) = .empty;
    var it = mem.splitSequence(u8, thread.participants, ", ");
    while (it.next()) |name| try names.append(arena, name);
    const out = try arena.alloc(Mailbox.Message, thread.messages);
    for (out, 0..) |*m, i| {
        const newest = i + 1 == out.len;
        const from = names.items[i % names.items.len];
        const said = if (newest)
            thread.snippet
        else
            try arena.print("Message {d} of “{s}”.", .{ i + 1, thread.subject });
        var html: Writer.Allocating = .init(arena);
        try html.writer.writeAll("<p>");
        try escape(&html.writer, said);
        try html.writer.writeAll("</p><p>Thanks,<br>");
        try escape(&html.writer, from);
        try html.writer.writeAll("</p>");
        if (newest and i > 0) {
            try html.writer.writeAll("<blockquote type=\"cite\"><p>");
            try escape(&html.writer, out[i - 1].snippet);
            try html.writer.writeAll("</p></blockquote>");
        }
        const back: i64 = @intCast(out.len - 1 - i);
        // An agenda comes with one, to open.
        const files: []const Mailbox.Attachment = if (newest and mem.find(u8, thread.subject, "agenda") != null)
            try arena.dupe(Mailbox.Attachment, &.{.{
                .name = "agenda.txt",
                .mime = "text/plain",
                .content_id = "",
                .id = "",
                .data = try arena.print("{s}\n\n{s}\n", .{ thread.subject, thread.snippet }),
                .inline_shown = false,
            }})
        else
            &.{};
        m.* = .{
            .id = try arena.print("{s}.{d}", .{ thread.id, i }),
            .from = from,
            .address = if (mem.eql(u8, from, "me")) "me@example.com" else try arena.print("{s}@example.com", .{from}),
            .date = thread.date - back * 3 * 3600,
            .html = html.written(),
            .text = try arena.print("{s}\n\nThanks,\n{s}", .{ said, from }),
            .snippet = said,
            .attachments = files,
            .unread = newest and thread.unread,
            .message_id = try arena.print("<{s}.{d}@sample>", .{ thread.id, i }),
            .references = "",
            .reply_to = if (mem.eql(u8, from, "me"))
                "me@example.com"
            else
                try arena.print("{s} <{s}@example.com>", .{ from, from }),
            .to = "me@example.com",
            .cc = "",
            .sent = mem.eql(u8, from, "me"),
            // A newsletter can be left by mail.
            .unsubscribe = if (mem.eql(u8, from, "Zig Weekly"))
                "<mailto:leave@zig-weekly.example?subject=unsubscribe>, <https://zig-weekly.example/leave>"
            else
                "",
            .one_click = false,
            // GitHub's mail links its page, and lunch comes with an invitation.
            .action = if (mem.eql(u8, from, "GitHub"))
                .{ .name = "View workflow run", .url = "https://github.com/rockorager/siv/actions" }
            else
                null,
            .invite = if (i == 0 and mem.eql(u8, thread.subject, "Lunch tomorrow"))
                try cards.invite(arena, try lunch(arena, thread.date))
            else
                null,
        };
    }
    return out;
}

/// An invitation to lunch at noon the day after `date`.
fn lunch(arena: Allocator, date: i64) ![]const u8 {
    const epoch = std.time.epoch;
    const seconds: epoch.EpochSeconds = .{ .secs = @intCast(@max(date + 24 * 3600, 0)) };
    const year_day = seconds.getEpochDay().calculateYearDay();
    const month_day = year_day.calculateMonthDay();
    const ymd = try arena.print("{d:0>4}{d:0>2}{d:0>2}", .{
        year_day.year,
        @backingInt(month_day.month),
        month_day.day_index + 1,
    });
    return arena.print(
        "BEGIN:VCALENDAR\r\nMETHOD:REQUEST\r\nBEGIN:VEVENT\r\nSUMMARY:Lunch\r\n" ++
            "DTSTART;TZID=America/Chicago:{s}T120000\r\nDTEND;TZID=America/Chicago:{s}T130000\r\n" ++
            "LOCATION:Taco place on Lake St\r\nORGANIZER;CN=Sam Torres:mailto:sam@example.com\r\n" ++
            "END:VEVENT\r\nEND:VCALENDAR\r\n",
        .{ ymd, ymd },
    );
}

fn escape(w: *Writer, text: []const u8) !void {
    for (text) |b| try switch (b) {
        '&' => w.writeAll("&amp;"),
        '<' => w.writeAll("&lt;"),
        '>' => w.writeAll("&gt;"),
        else => w.writeByte(b),
    };
}

/// The user, on the threads' messages.
const me: Mailbox.Person = .{ .name = "", .address = "me@example.com" };

pub fn load(mail: *Mailbox, now: i64) !void {
    var map: std.EnumArray(L, Mailbox.Label) = .initUndefined();
    inline for (.{ .inbox, .starred, .sent, .drafts, .spam, .trash }) |system| map.set(system, system);
    for (user_labels) |u| {
        const rgb: Rgb = .{ .r = @truncate(u[3] >> 16), .g = @truncate(u[3] >> 8), .b = @truncate(u[3]) };
        map.set(u[0], try mail.addLabel(.{ .id = u[1], .name = u[2], .kind = .user, .color = rgb }));
    }
    for (threads, 0..) |s, i| {
        var labels: [user_labels.len + 6]Mailbox.Label = undefined;
        for (s.labels, 0..) |l, k| labels[k] = map.get(l);
        var id_buf: [16]u8 = undefined;
        var people_buf: [64]u8 = undefined;
        // A thread of more than one message is the sender and the replies.
        const first_name = s.from[0 .. mem.findScalar(u8, s.from, ' ') orelse s.from.len];
        const participants = if (s.messages == 1) s.from else try mem.print(&people_buf, "{s}, me", .{first_name});
        // The sender wrote to the user, who answered three hours before
        // where a thread has more than one message.
        const date = now - @as(i64, s.minutes_ago) * 60;
        var address_buf: [96]u8 = undefined;
        const sender: Mailbox.Person = .{ .name = s.from, .address = try address(&address_buf, s.from) };
        const notes = [_]Mailbox.NewNote{
            .{ .date = date - 3 * 3600, .from = me, .to = &.{sender}, .cc = &.{} },
            .{ .date = date, .from = sender, .to = &.{me}, .cc = &.{} },
        };
        _ = try mail.addThread(.{
            .id = try mem.print(&id_buf, "sample-{d}", .{i}),
            .participants = participants,
            .subject = s.subject,
            .snippet = s.snippet,
            .date = date,
            .messages = s.messages,
            .labels = labels[0..s.labels.len],
            .unread = s.unread,
            .notes = if (s.messages > 1) &notes else notes[1..],
        });
    }
}

/// Tells `contacts` who is on the threads, as `load` notes them.
pub fn people(contacts: *Contacts, now: i64) !void {
    for (threads) |s| {
        var address_buf: [96]u8 = undefined;
        var buf: [192]u8 = undefined;
        const entry = try mem.print(&buf, "{s} <{s}>", .{ s.from, try address(&address_buf, s.from) });
        const ms = (now - @as(i64, s.minutes_ago) * 60) * 1000;
        try contacts.note(.heard, entry, ms);
        if (s.messages > 1) try contacts.note(.wrote, entry, ms - 3 * 3600 * 1000);
    }
}

/// An address made from a name: Maya Okafor is maya.okafor@example.com.
fn address(buf: *[96]u8, name: []const u8) ![]const u8 {
    var w: Writer = .fixed(buf);
    var dot = false;
    for (name) |c| {
        if (c == ' ') dot = true;
        if (!ascii.isAlphanumeric(c)) continue;
        if (dot) try w.writeByte('.');
        dot = false;
        try w.writeByte(ascii.toLower(c));
    }
    try w.writeAll("@example.com");
    return w.buffered();
}

const threads = [_]Sample{
    t(
        "Maya Okafor",
        "Offsite agenda, final",
        "Moved the roadmap session to Thursday morning so Ravi can join from Lisbon.",
        7,
        4,
        &.{ .inbox, .work, .starred },
        true,
    ),
    t(
        "GitHub",
        "[siv] CI failed on main",
        "The test-render-vulkan job failed after 14m 02s: validation error in vkQueueSubmit2.",
        22,
        1,
        &.{ .inbox, .work },
        true,
    ),
    t(
        "Mom",
        "Sunday dinner?",
        "Your dad is making the lamb again. Bring the kids, and the good bread if you pass the bakery.",
        41,
        3,
        &.{ .inbox, .family },
        true,
    ),
    t(
        "Priya Raman",
        "Candidate packet: Jonas Weber",
        "Attached his take-home and the panel notes. Strong on systems, quiet in the design round.",
        1 * hour + 10,
        2,
        &.{ .inbox, .work, .hiring },
        true,
    ),
    t(
        "Delta",
        "Your trip to Lisbon is confirmed",
        "Confirmation HX7K2P. Departs Tue 6:05 PM from MSP, arrives Wed 10:40 AM.",
        2 * hour,
        1,
        &.{ .inbox, .travel, .receipts },
        false,
    ),
    t(
        "Ravi Menon",
        "Re: render thread priorities",
        "I tried SCHED_FIFO for the compositor thread and frame pacing got worse, not better.",
        3 * hour,
        6,
        &.{ .inbox, .work },
        false,
    ),
    t(
        "Zig Weekly",
        "Issue 212: the 0.17 build system",
        "This week: addPassthruArgs, cache poisoning, and why @cImport had to go.",
        5 * hour,
        1,
        &.{ .inbox, .newsletters },
        true,
    ),
    t(
        "Sam Torres",
        "Lunch tomorrow",
        "Taco place on Lake St at noon? I'll grab a table if I'm early.",
        6 * hour,
        2,
        &.{.inbox},
        false,
    ),
    t(
        "Stripe",
        "Receipt from Fastmail",
        "Amount paid $60.00. Standard plan, 12 months. Card ending 4242.",
        9 * hour,
        1,
        &.{.receipts},
        false,
    ),
    t(
        "Lena Fischer",
        "Re: offer letter",
        "Thank you! I've signed and sent it back. Looking forward to starting on the 1st.",
        1 * day,
        5,
        &.{ .inbox, .work, .hiring, .starred },
        false,
    ),
    t(
        "Dad",
        "Photos from the lake",
        "Finally got these off the camera. The one of Ada with the fish is my favorite.",
        1 * day + 2 * hour,
        1,
        &.{ .family, .starred },
        false,
    ),
    t(
        "Hotel Avenida",
        "Your reservation request",
        "We are pleased to confirm 3 nights, arriving 12 Nov. Breakfast is included.",
        1 * day + 5 * hour,
        2,
        &.{ .inbox, .travel },
        false,
    ),
    t(
        "Jonas Weber",
        "Question about the take-home",
        "Should the parser stream, or is it fine to read the whole file first?",
        1 * day + 8 * hour,
        3,
        &.{ .work, .hiring, .waiting },
        false,
    ),
    t(
        "Linear",
        "3 issues assigned to you",
        "PAR-12 Message list virtualization, PAR-14 Label picker, PAR-15 Undo archive.",
        2 * day,
        1,
        &.{ .inbox, .work },
        true,
    ),
    t(
        "Maya Okafor",
        "Budget numbers for Q1",
        "Can you sanity check the infra line? It looks high but I might be double counting.",
        2 * day + 3 * hour,
        4,
        &.{ .work, .waiting },
        false,
    ),
    t(
        "Amazon",
        "Your order has shipped",
        "Keychron Q1 Pro will arrive Friday. Track your package.",
        2 * day + 6 * hour,
        1,
        &.{.receipts},
        false,
    ),
    t(
        "Ada's school",
        "Field trip permission slip",
        "Please sign and return by Friday. The trip to the science museum is on the 14th.",
        3 * day,
        1,
        &.{ .inbox, .family, .waiting },
        true,
    ),
    t(
        "This Week in Rust",
        "Issue 571",
        "Rust 1.92 ships async closures in traits, plus a look at the new trait solver.",
        3 * day + 4 * hour,
        1,
        &.{.newsletters},
        false,
    ),
    t(
        "Ravi Menon",
        "Lisbon dinner spots",
        "Cervejaria Ramiro is a must. Book ahead or come at 5 and wait with everyone else.",
        4 * day,
        2,
        &.{ .travel, .starred },
        false,
    ),
    t(
        "Ana Lima",
        "Re: siv accessibility review",
        "Orca reads the sidebar fine, but the table headers announce twice. Notes inline.",
        4 * day + 2 * hour,
        7,
        &.{ .work, .starred },
        false,
    ),
    t(
        "Fastmail",
        "Your storage is 80% full",
        "You're using 24 GB of 30 GB. Upgrade or clear out old messages.",
        5 * day,
        1,
        &.{.inbox},
        false,
    ),
    t(
        "Grandma",
        "Recipe you asked for",
        "Two cups flour, one of sugar, a pinch of salt, and the secret is the browned butter.",
        6 * day,
        2,
        &.{ .family, .someday },
        false,
    ),
    t(
        "Priya Raman",
        "Panel schedule next week",
        "Can you take the systems round on Tuesday at 2? Two candidates back to back.",
        6 * day + 5 * hour,
        3,
        &.{ .work, .hiring },
        false,
    ),
    t(
        "Kickstarter",
        "A project you backed has an update",
        "Production is two weeks behind, but the first units ship in March.",
        8 * day,
        1,
        &.{ .newsletters, .someday },
        false,
    ),
    t(
        "Sam Torres",
        "Climbing Saturday?",
        "The new gym in Northeast has a bouldering wall. Want to try it?",
        9 * day,
        4,
        &.{.someday},
        false,
    ),
    t(
        "City of Minneapolis",
        "Water bill available",
        "Your bill of $84.12 is due on the 28th. Pay online or by phone.",
        10 * day,
        1,
        &.{ .receipts, .waiting },
        false,
    ),
    t(
        "Mom",
        "Thanksgiving plans",
        "We're doing it at your aunt's this year. Can you bring pie? Two, maybe three.",
        11 * day,
        9,
        &.{.family},
        false,
    ),
    t(
        "Lobste.rs Digest",
        "Top stories this week",
        "A tour of io_uring, Zig's new std.Io, and why your terminal is slow.",
        12 * day,
        1,
        &.{.newsletters},
        false,
    ),
    t(
        "Maya Okafor",
        "Re: performance reviews",
        "Drafts are due on the 30th. I'll send the template this week.",
        14 * day,
        3,
        &.{.work},
        false,
    ),
    t(
        "Unknown sender",
        "You have won a gift card",
        "Claim your $500 reward now. Click the link below before it expires.",
        15 * day,
        1,
        &.{.spam},
        true,
    ),
    t(
        "Me",
        "Notes to self: parcel",
        "Keyboard first. Every action has a key and a click. Labels are first class.",
        2 * hour,
        1,
        &.{ .sent, .starred, .someday },
        false,
    ),
    t("Me", "Re: Lunch tomorrow", "Sounds good, see you at noon.", 5 * hour, 2, &.{.sent}, false),
    t(
        "Me",
        "Draft: reply to Ana",
        "Thanks for the review. On the double announcement, I think the header cell",
        30,
        1,
        &.{.drafts},
        false,
    ),
};