3 files changed, 146 insertions, 25 deletions

diff --git a/src/storage/image-manager/exif.zig b/src/storage/image-manager/exif.zig
new file mode 100644
index 0000000..02199cf
--- /dev/null
+++ b/src/storage/image-manager/exif.zig
@@ -0,0 +1,54 @@
+const std = @import("std");
+const exif = @cImport(@cInclude("libexif/exif-data.h"));
+const cstd = @cImport(@cInclude("time.h"));
+
+const tags = [_]c_uint {
+    exif.EXIF_TAG_DATE_TIME,
+    exif.EXIF_TAG_DATE_TIME_ORIGINAL,
+    exif.EXIF_TAG_DATE_TIME_DIGITIZED,
+};
+
+pub fn get_date_time(path: [*:0]const u8) ?i64 {
+    const exif_data = exif.exif_data_new_from_file(path);
+    defer exif.exif_data_unref(exif_data);
+
+    if (exif_data == null) {
+        return null;
+    }
+
+    var entry: ?[*c]exif.struct__ExifEntry = null;
+    for (0..exif.EXIF_IFD_COUNT) |index| {
+        for (tags) |tag| {
+            entry = exif.exif_content_get_entry((exif_data.*).ifd[index], tag);
+
+            if (entry) |_| { break; }
+        }
+
+        if (entry) |_| { break; }
+    }
+
+    if (entry == null) {
+        return null;
+    }
+
+    const c_data = (entry.?.*).data;
+
+    return parse_date(c_data);
+}
+
+extern fn strptime(
+   s: [*c]const u8,
+   format: [*c]const u8,
+    tm: *cstd.tm,
+) ?*const u8;
+
+extern fn timegm(tm: *cstd.tm) i64;
+
+fn parse_date(date: [*:0]const u8) ?i64 {
+    var tm: cstd.tm = std.mem.zeroes(cstd.tm);
+    if (strptime(date, "%Y:%m:%d %H:%M:%S", &tm)) |_| {
+        return timegm(&tm);
+    }
+
+    return null;
+}
diff --git a/src/storage/image-manager/image.zig b/src/storage/image-manager/image.zig
index 91a094e..b11b7b1 100644
--- a/src/storage/image-manager/image.zig
+++ b/src/storage/image-manager/image.zig
@@ -1,6 +1,8 @@
 const std = @import("std");
 const Storage = @import("../root.zig");
 
+const exif = @import("exif.zig");
+
 const id_size = 32;
 
 const log = std.log.scoped(.image);
@@ -19,6 +21,7 @@ fn new_id() [id_size]u8 {
 const Self = @This();
 
 id: []const u8,
+timestamp: ?i64,
 
 pub fn new(
     storage: *Storage,
@@ -28,8 +31,11 @@ pub fn new(
     var dir = try storage.dir.openDir("image", .{});
     defer dir.close();
 
-    var file_name: [id_size+4]u8 = undefined;
-    const self: Self = .{ .id = &new_id() };
+    var self: Self = undefined;
+
+    self.id = try storage.allocator.dupe(u8, &new_id());
+
+    var file_name: [id_size + 4]u8 = undefined;
     @memcpy(file_name[0..id_size], self.id);
     @memcpy(file_name[id_size..], ".jpg");
 
@@ -43,14 +49,17 @@ pub fn new(
 
     try file_writer.interface.flush();
 
-    log.info("uploaded {s} [{} bytes]", .{self.id, size});
+    log.info("uploaded {s} [{} bytes]", .{ self.id, size });
+
+    self.timestamp = try load_timestamp(storage, self.id);
 
     return self;
 }
 
-pub fn init(allocator: std.mem.Allocator, id: []const u8) !Self {
+pub fn init(storage: *Storage, id: []const u8) !Self {
     return .{
-        .id = try allocator.dupe(u8, id),
+        .id = try storage.allocator.dupe(u8, id),
+        .timestamp = try load_timestamp(storage, id),
     };
 }
 
@@ -61,7 +70,7 @@ pub fn file(self: *Self, storage: *Storage) !std.fs.File {
     };
     defer dir.close();
 
-    var file_name: [id_size+4]u8 = undefined;
+    var file_name: [id_size + 4]u8 = undefined;
     @memcpy(file_name[0..id_size], self.id);
     @memcpy(file_name[id_size..], ".jpg");
 
@@ -71,3 +80,20 @@ pub fn file(self: *Self, storage: *Storage) !std.fs.File {
 pub fn deinit(self: *Self, allocator: std.mem.Allocator) void {
     allocator.free(self.id);
 }
+
+fn load_timestamp(storage: *Storage, id: []const u8) !?i64 {
+    var dir = storage.dir.openDir("image", .{}) catch blk: {
+        try storage.dir.makeDir("image");
+        break :blk try storage.dir.openDir("image", .{});
+    };
+    defer dir.close();
+
+    var file_name: [id_size + 4]u8 = undefined;
+    @memcpy(file_name[0..id_size], id);
+    @memcpy(file_name[id_size..], ".jpg");
+
+    var path_buffer: [std.fs.max_path_bytes:0]u8 = std.mem.zeroes([std.fs.max_path_bytes:0]u8);
+    const path = try dir.realpath(&file_name, &path_buffer);
+
+    return exif.get_date_time(@ptrCast(path));
+}
diff --git a/src/storage/image-manager/root.zig b/src/storage/image-manager/root.zig
index 7742df2..7fa1607 100644
--- a/src/storage/image-manager/root.zig
+++ b/src/storage/image-manager/root.zig
@@ -1,24 +1,30 @@
 const std = @import("std");
 
-const Storage = @import("../root.zig");
+const memora = @import("memora");
+const Storage = memora.Storage;
 pub const Image = @import("image.zig");
 
 const Self = @This();
 
 pub const empty: Self = .{};
 
-items: std.ArrayList(Image) = .empty,
-rw_lock: std.Thread.RwLock = .{},
+const Timestamp = struct {
+    index: usize,
+    node: std.DoublyLinkedList.Node,
 
-pub const LockedImages = struct {
-    images: []Image,
-    rw_lock: *std.Thread.RwLock,
+    pub fn next(self: *Timestamp) ?*Timestamp {
+        return @fieldParentPtr("node", self.node.next orelse return null);
+    }
 
-    pub fn deinit(self: *const @This()) void {
-        self.rw_lock.unlockShared();
+    pub fn prev(self: *Timestamp) ?*Timestamp {
+        return @fieldParentPtr("node", self.node.prev orelse return null);
     }
 };
 
+items: std.ArrayList(Image) = .empty,
+rw_lock: std.Thread.RwLock = .{},
+timestamp_order: std.DoublyLinkedList = .{},
+
 pub fn init(
     self: *Self,
     storage: *Storage,
@@ -35,32 +41,67 @@ pub fn init(
 
     while (try iterator.next()) |entry| {
         if (entry.kind == .file and std.mem.endsWith(u8, entry.name, ".jpg")) {
-            try self.items.append(
+            try self.add(
                 storage.allocator,
-                try .init(storage.allocator, entry.name[0..entry.name.len - 4])
+                try .init(storage, entry.name[0..entry.name.len - 4])
             );
         }
     }
 }
 
-pub fn add(
+pub fn add(self: *Self, allocator: std.mem.Allocator, image: Image) !void {
+    self.rw_lock.lock();
+    defer self.rw_lock.unlock();
+
+    try self.items.append(
+        allocator,
+        image,
+    );
+
+    var current = self.timestamp_order.first;
+
+    if (current == null) {
+        const timestamp = try allocator.create(Timestamp);
+        timestamp.index = self.items.items.len - 1;
+        self.timestamp_order.append(&timestamp.node);
+        return;
+    }
+
+    while (current) |c| {
+        const index = @as(*Timestamp, @fieldParentPtr("node", c)).index;
+        if (image.timestamp orelse 0 > self.items.items[index].timestamp orelse 0) {
+            const timestamp = try allocator.create(Timestamp);
+            timestamp.index = self.items.items.len - 1;
+            self.timestamp_order.insertBefore(c, &timestamp.node);
+            break;
+        }
+
+        current = c.next;
+    }
+}
+
+pub fn save(
     self: *Self,
     storage: *Storage,
     reader: *std.Io.Reader,
     size: usize,
 ) !void {
-    self.rw_lock.lock();
-    defer self.rw_lock.unlock();
+    return self.add(storage.allocator, try Image.new(storage, reader, size));
+}
 
-    try self.items.append(
-        storage.allocator,
-        try Image.new(storage, reader, size),
-    );
+pub fn list(self: *Self) memora.locked.Shared([]Image) {
+    self.rw_lock.lockShared();
+    return .{
+        .value = self.items.items,
+        .rw_lock = &self.rw_lock,
+    };
 }
 
-pub fn list(self: *Self) LockedImages {
+pub fn first_by_timestamp(self: *Self) memora.locked.Shared(?*Timestamp) {
+    self.rw_lock.lockShared();
     return .{
-        .images = self.items.items,
+        .value = if (self.timestamp_order.first) |first| @fieldParentPtr("node", first)
+        else null,
         .rw_lock = &self.rw_lock,
     };
 }