From 66c3667bc36a4d6f133dd934fb0166265a1cecd2 Mon Sep 17 00:00:00 2001
From: Martin Ashby <martin@ashbysoft.com>
Date: Sat, 7 Oct 2023 22:23:33 +0100
Subject: Implement main application

---
 src/main.zig | 82 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 82 insertions(+)

diff --git a/src/main.zig b/src/main.zig
index ca1fcd8..3e5bd80 100644
--- a/src/main.zig
+++ b/src/main.zig
@@ -1,6 +1,88 @@
 const std = @import("std");
+const Zip = @import("zip");
 const SeekableHttpRange = @import("seekable_http_range.zig");
 
+pub fn main() !void {
+    var gpa = std.heap.GeneralPurposeAllocator(.{}){};
+    defer _ = gpa.deinit();
+    const a = gpa.allocator();
+
+    var args = try std.process.argsAlloc(a);
+    defer std.process.argsFree(a, args);
+    if (args.len < 2) {
+        try printHelpAndExit("No URL specified");
+        return;
+    }
+    if (args.len < 3) {
+        try printHelpAndExit("No FILES specified");
+        return;
+    }
+    const url = args[1];
+    const files = args[2..];
+    
+    // TODO general purpose options handling
+    if (std.mem.eql(u8, url, "-h") or std.mem.eql(u8, url, "--help")) {
+        try printHelpAndExit(null);
+        return;
+    }
+
+    var client = std.http.Client{.allocator = a};
+    defer client.deinit();
+
+    var range = try SeekableHttpRange.init(.{
+        .allocator = a,
+        .client = &client,
+        .url = url,
+        .buffer_size = 8192,
+    });
+    defer range.deinit();
+
+    var zip = try Zip.from(a, &range);
+    defer zip.deinit();
+
+    var at_least_one_success = false;
+    for (files) |file| {
+        cdhlp: for (zip.central_directory_headers.items, 0..) |cdh, ix| {
+            if (std.mem.eql(u8, file, cdh.file_name)) {
+                const cwd = std.fs.cwd();
+                if (std.fs.path.dirname(file)) |dirname| {
+                    try cwd.makePath(dirname);
+                }
+                var outfile = try cwd.createFile(cdh.file_name, .{});
+                defer outfile.close();
+                try zip.extract(ix, &range, outfile.writer());
+                at_least_one_success = true;
+                break :cdhlp;
+            }
+        } else {
+            try std.fmt.format(std.io.getStdErr().writer(), "File {s} not found in zip\n", .{file});
+        }
+    }
+    if (!at_least_one_success) {
+        try std.io.getStdErr().writeAll("No files successfully downloded\n");
+        std.os.exit(1);
+    }
+}
+
+fn printHelpAndExit(comptime errmsg: ?[]const u8) !void {
+    const usage = \\Usage:
+        \\zipdl URL FILES...
+        \\  URL is the http(s) URL of a ZIP file 
+        \\  FILES are the files to be extracted from the remote ZIP
+        \\
+        ;
+    if (errmsg) |err| {
+        try std.io.getStdErr().writeAll(err);
+        try std.io.getStdErr().writeAll("\n\n");
+        try std.io.getStdErr().writeAll(usage);
+        std.os.exit(2);
+    } else {
+        try std.io.getStdErr().writeAll(usage);
+        std.os.exit(0);
+    }
+    unreachable;
+}
+
 test {
     _ = SeekableHttpRange;
 }
\ No newline at end of file
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