//! Default test runner for unit tests.
const builtin = @import("builtin");
const std = @import("std");
const io = std.io;
const testing = std.testing;

pub const std_options = .{
    .logFn = log,
};

var log_err_count: usize = 0;
var fba_buffer: [8192]u8 = undefined;
var fba = std.heap.FixedBufferAllocator.init(&fba_buffer);

const crippled = switch (builtin.zig_backend) {
    .stage2_riscv64 => true,
    else => false,
};

pub fn main() void {
    @disableInstrumentation();

    if (crippled) {
        return mainSimple() catch @panic("test failure\n");
    }

    const args = std.process.argsAlloc(fba.allocator()) catch
        @panic("unable to parse command line args");

    var listen = false;

    for (args[1..]) |arg| {
        if (std.mem.eql(u8, arg, "--listen=-")) {
            listen = true;
        } else if (std.mem.startsWith(u8, arg, "--seed=")) {
            testing.random_seed = std.fmt.parseUnsigned(u32, arg["--seed=".len..], 0) catch
                @panic("unable to parse --seed command line argument");
        } else {
            @panic("unrecognized command line argument");
        }
    }

    fba.reset();

    if (listen) {
        return mainServer() catch @panic("internal test runner failure");
    } else {
        return mainTerminal();
    }
}

fn mainServer() !void {
    @disableInstrumentation();
    var server = try std.zig.Server.init(.{
        .gpa = fba.allocator(),
        .in = std.io.getStdIn(),
        .out = std.io.getStdOut(),
        .zig_version = builtin.zig_version_string,
    });
    defer server.deinit();

    while (true) {
        const hdr = try server.receiveMessage();
        switch (hdr.tag) {
            .exit => {
                return std.process.exit(0);
            },
            .query_test_metadata => {
                testing.allocator_instance = .{};
                defer if (testing.allocator_instance.deinit() == .leak) {
                    @panic("internal test runner memory leak");
                };

                var string_bytes: std.ArrayListUnmanaged(u8) = .{};
                defer string_bytes.deinit(testing.allocator);
                try string_bytes.append(testing.allocator, 0); // Reserve 0 for null.

                const test_fns = builtin.test_functions;
                const names = try testing.allocator.alloc(u32, test_fns.len);
                defer testing.allocator.free(names);
                const expected_panic_msgs = try testing.allocator.alloc(u32, test_fns.len);
                defer testing.allocator.free(expected_panic_msgs);

                for (test_fns, names, expected_panic_msgs) |test_fn, *name, *expected_panic_msg| {
                    name.* = @as(u32, @intCast(string_bytes.items.len));
                    try string_bytes.ensureUnusedCapacity(testing.allocator, test_fn.name.len + 1);
                    string_bytes.appendSliceAssumeCapacity(test_fn.name);
                    string_bytes.appendAssumeCapacity(0);
                    expected_panic_msg.* = 0;
                }

                try server.serveTestMetadata(.{
                    .names = names,
                    .expected_panic_msgs = expected_panic_msgs,
                    .string_bytes = string_bytes.items,
                });
            },

            .run_test => {
                testing.allocator_instance = .{};
                log_err_count = 0;
                const index = try server.receiveBody_u32();
                const test_fn = builtin.test_functions[index];
                var fail = false;
                var skip = false;
                is_fuzz_test = false;
                test_fn.func() catch |err| switch (err) {
                    error.SkipZigTest => skip = true,
                    else => {
                        fail = true;
                        if (@errorReturnTrace()) |trace| {
                            std.debug.dumpStackTrace(trace.*);
                        }
                    },
                };
                const leak = testing.allocator_instance.deinit() == .leak;
                try server.serveTestResults(.{
                    .index = index,
                    .flags = .{
                        .fail = fail,
                        .skip = skip,
                        .leak = leak,
                        .fuzz = is_fuzz_test,
                        .log_err_count = std.math.lossyCast(
                            @TypeOf(@as(std.zig.Server.Message.TestResults.Flags, undefined).log_err_count),
                            log_err_count,
                        ),
                    },
                });
            },
            .start_fuzzing => {
                const index = try server.receiveBody_u32();
                const test_fn = builtin.test_functions[index];
                while (true) {
                    testing.allocator_instance = .{};
                    defer if (testing.allocator_instance.deinit() == .leak) std.process.exit(1);
                    log_err_count = 0;
                    is_fuzz_test = false;
                    test_fn.func() catch |err| switch (err) {
                        error.SkipZigTest => continue,
                        else => {
                            if (@errorReturnTrace()) |trace| {
                                std.debug.dumpStackTrace(trace.*);
                            }
                            std.debug.print("failed with error.{s}\n", .{@errorName(err)});
                            std.process.exit(1);
                        },
                    };
                    if (!is_fuzz_test) @panic("missed call to std.testing.fuzzInput");
                    if (log_err_count != 0) @panic("error logs detected");
                }
            },

            else => {
                std.debug.print("unsupported message: {x}\n", .{@intFromEnum(hdr.tag)});
                std.process.exit(1);
            },
        }
    }
}

fn mainTerminal() void {
    @disableInstrumentation();
    const test_fn_list = builtin.test_functions;
    var ok_count: usize = 0;
    var skip_count: usize = 0;
    var fail_count: usize = 0;
    var fuzz_count: usize = 0;
    const root_node = std.Progress.start(.{
        .root_name = "Test",
        .estimated_total_items = test_fn_list.len,
    });
    const have_tty = std.io.getStdErr().isTty();

    var async_frame_buffer: []align(builtin.target.stackAlignment()) u8 = undefined;
    // TODO this is on the next line (using `undefined` above) because otherwise zig incorrectly
    // ignores the alignment of the slice.
    async_frame_buffer = &[_]u8{};

    var leaks: usize = 0;
    for (test_fn_list, 0..) |test_fn, i| {
        testing.allocator_instance = .{};
        defer {
            if (testing.allocator_instance.deinit() == .leak) {
                leaks += 1;
            }
        }
        testing.log_level = .warn;

        const test_node = root_node.start(test_fn.name, 0);
        if (!have_tty) {
            std.debug.print("{d}/{d} {s}...", .{ i + 1, test_fn_list.len, test_fn.name });
        }
        is_fuzz_test = false;
        if (test_fn.func()) |_| {
            ok_count += 1;
            test_node.end();
            if (!have_tty) std.debug.print("OK\n", .{});
        } else |err| switch (err) {
            error.SkipZigTest => {
                skip_count += 1;
                if (have_tty) {
                    std.debug.print("{d}/{d} {s}...SKIP\n", .{ i + 1, test_fn_list.len, test_fn.name });
                } else {
                    std.debug.print("SKIP\n", .{});
                }
                test_node.end();
            },
            else => {
                fail_count += 1;
                if (have_tty) {
                    std.debug.print("{d}/{d} {s}...FAIL ({s})\n", .{
                        i + 1, test_fn_list.len, test_fn.name, @errorName(err),
                    });
                } else {
                    std.debug.print("FAIL ({s})\n", .{@errorName(err)});
                }
                if (@errorReturnTrace()) |trace| {
                    std.debug.dumpStackTrace(trace.*);
                }
                test_node.end();
            },
        }
        fuzz_count += @intFromBool(is_fuzz_test);
    }
    root_node.end();
    if (ok_count == test_fn_list.len) {
        std.debug.print("All {d} tests passed.\n", .{ok_count});
    } else {
        std.debug.print("{d} passed; {d} skipped; {d} failed.\n", .{ ok_count, skip_count, fail_count });
    }
    if (log_err_count != 0) {
        std.debug.print("{d} errors were logged.\n", .{log_err_count});
    }
    if (leaks != 0) {
        std.debug.print("{d} tests leaked memory.\n", .{leaks});
    }
    if (fuzz_count != 0) {
        std.debug.print("{d} fuzz tests found.\n", .{fuzz_count});
    }
    if (leaks != 0 or log_err_count != 0 or fail_count != 0) {
        std.process.exit(1);
    }
}

pub fn log(
    comptime message_level: std.log.Level,
    comptime scope: @Type(.EnumLiteral),
    comptime format: []const u8,
    args: anytype,
) void {
    @disableInstrumentation();
    if (@intFromEnum(message_level) <= @intFromEnum(std.log.Level.err)) {
        log_err_count +|= 1;
    }
    if (@intFromEnum(message_level) <= @intFromEnum(testing.log_level)) {
        std.debug.print(
            "[" ++ @tagName(scope) ++ "] (" ++ @tagName(message_level) ++ "): " ++ format ++ "\n",
            args,
        );
    }
}

/// Simpler main(), exercising fewer language features, so that
/// work-in-progress backends can handle it.
pub fn mainSimple() anyerror!void {
    @disableInstrumentation();
    // is the backend capable of printing to stderr?
    const enable_print = switch (builtin.zig_backend) {
        else => false,
    };
    // is the backend capable of using std.fmt.format to print a summary at the end?
    const print_summary = switch (builtin.zig_backend) {
        else => false,
    };

    var passed: u64 = 0;
    var skipped: u64 = 0;
    var failed: u64 = 0;

    // we don't want to bring in File and Writer if the backend doesn't support it
    const stderr = if (comptime enable_print) std.io.getStdErr() else {};

    for (builtin.test_functions) |test_fn| {
        if (test_fn.func()) |_| {
            if (enable_print) {
                stderr.writeAll(test_fn.name) catch {};
                stderr.writeAll("... ") catch {};
                stderr.writeAll("PASS\n") catch {};
            }
        } else |err| if (enable_print) {
            if (enable_print) {
                stderr.writeAll(test_fn.name) catch {};
                stderr.writeAll("... ") catch {};
            }
            if (err != error.SkipZigTest) {
                if (enable_print) stderr.writeAll("FAIL\n") catch {};
                failed += 1;
                if (!enable_print) return err;
                continue;
            }
            if (enable_print) stderr.writeAll("SKIP\n") catch {};
            skipped += 1;
            continue;
        }
        passed += 1;
    }
    if (enable_print and print_summary) {
        stderr.writer().print("{} passed, {} skipped, {} failed\n", .{ passed, skipped, failed }) catch {};
    }
    if (failed != 0) std.process.exit(1);
}

const FuzzerSlice = extern struct {
    ptr: [*]const u8,
    len: usize,

    inline fn toSlice(s: FuzzerSlice) []const u8 {
        return s.ptr[0..s.len];
    }
};

var is_fuzz_test: bool = undefined;

extern fn fuzzer_next() FuzzerSlice;

pub fn fuzzInput(options: testing.FuzzInputOptions) []const u8 {
    @disableInstrumentation();
    if (crippled) return "";
    is_fuzz_test = true;
    if (builtin.fuzz) return fuzzer_next().toSlice();
    if (options.corpus.len == 0) return "";
    var prng = std.Random.DefaultPrng.init(testing.random_seed);
    const random = prng.random();
    return options.corpus[random.uintLessThan(usize, options.corpus.len)];
}
