const std = @import("std");

pub fn main() !void {
    var gpa = std.heap.GeneralPurposeAllocator(.{}){};
    defer _ = gpa.deinit();

    const argv = try std.process.argsAlloc(gpa.allocator());
    defer std.process.argsFree(gpa.allocator(), argv);

    const filename = argv[1];

    const contents = try std.fs.cwd().readFileAlloc(gpa.allocator(), filename, 50 * 1024 * 1024);
    defer gpa.allocator().free(contents);

    const stdout = std.io.getStdOut();
    const out = stdout.writer();

    try out.writeAll(
        \\/* AUTOMATICALLY GENERATED by gen_table_fourcc.py. You should modify
        \\   that script instead of adding here entries manually! */
        \\static const struct drmFormatModifierInfo drm_format_modifier_table[] = {
        \\    { DRM_MODIFIER_INVALID(NONE, INVALID) },
        \\    { DRM_MODIFIER_LINEAR(NONE, LINEAR) },
        \\
    );
    var line_iter = std.mem.splitScalar(u8, contents, '\n');
    check_each_line: while (line_iter.next()) |line| {
        errdefer std.log.debug("line = \"{}\"", .{std.zig.fmtEscapes(line)});
        if (matchStart(line, "#define I915_FORMAT_MOD_")) |after| {
            const modifier_end = std.mem.indexOfAny(u8, after, "\t ") orelse return error.Invalid;
            const modifier = after[0..modifier_end];
            for (modifier) |character| {
                if (character != '_' and !std.ascii.isAlphanumeric(character)) {
                    continue :check_each_line;
                }
            }
            try out.print(
                \\    {{ DRM_MODIFIER_INTEL({[modifier]s}, {[modifier]s}) }},
                \\
            , .{
                .modifier = modifier,
            });
        } else if (matchStart(line, "#define DRM_FORMAT_MOD_")) |after| {
            const end_of_identifier = std.mem.indexOfAny(u8, after, "\t ") orelse return error.Invalid;
            const identifier = after[0..end_of_identifier];

            const end_of_vendor = std.mem.indexOfScalar(u8, identifier, '_') orelse continue;
            const vendor_str = identifier[0..end_of_vendor];
            const modifier = identifier[end_of_vendor + 1 ..];

            for (modifier) |character| {
                if (character != '_' and !std.ascii.isAlphanumeric(character)) {
                    continue :check_each_line;
                }
            }

            const Vendor = enum { ARM, SAMSUNG, QCOM, VIVANTE, NVIDIA, BROADCOM, ALLWINNER };

            const vendor = std.meta.stringToEnum(Vendor, vendor_str) orelse continue;

            if (vendor == .ARM) {
                if (std.mem.eql(u8, modifier, "TYPE_AFBC")) continue;
                if (std.mem.eql(u8, modifier, "TYPE_MISC")) continue;
                if (std.mem.eql(u8, modifier, "TYPE_AFRC")) continue;
            }

            try out.print(
                \\    {{ DRM_MODIFIER({[vendor]s}, {[modifier]s}, {[modifier]s}) }},
                \\
            , .{
                .vendor = @tagName(vendor),
                .modifier = modifier,
            });
        }
    }
    try out.writeAll(
        \\};
        \\static const struct drmFormatModifierVendorInfo drm_format_modifier_vendor_table[] = {
        \\
    );

    line_iter.reset();
    check_each_line: while (line_iter.next()) |line| {
        if (matchStart(line, "#define DRM_FORMAT_MOD_VENDOR_")) |after| {
            const modifier_end = std.mem.indexOfAny(u8, after, "\t ") orelse return error.Invalid;
            const modifier = after[0..modifier_end];

            for (modifier) |character| {
                if (character != '_' and !std.ascii.isAlphanumeric(character)) {
                    continue :check_each_line;
                }
            }

            try out.print(
                \\    {{ DRM_FORMAT_MOD_VENDOR_{[modifier]s}, "{[modifier]s}" }},
                \\
            , .{
                .modifier = modifier,
            });
        }
    }
    try out.writeAll(
        \\};
        \\
    );
}

fn matchStart(haystack: []const u8, needle: []const u8) ?[]const u8 {
    if (std.mem.startsWith(u8, haystack, needle)) {
        return haystack[needle.len..];
    }
    return null;
}