const std = @import("std");

pub const Routes = @import("src/Routes.zig");
pub const GenerateMimeTypes = @import("src/GenerateMimeTypes.zig");

const zmpl_build = @import("zmpl");
const Environment = enum { development, testing, production };
const builtin = @import("builtin");

const use_llvm_default = builtin.os.tag != .linux;

pub fn build(b: *std.Build) !void {
    const target = b.standardTargetOptions(.{});
    const optimize = b.standardOptimizeOption(.{});
    const templates_paths = try zmpl_build.templatesPaths(
        b.allocator,
        &.{
            .{ .prefix = "views", .path = &.{ "src", "app", "views" } },
            .{ .prefix = "mailers", .path = &.{ "src", "app", "mailers" } },
        },
    );

    const lib = b.addStaticLibrary(.{
        .name = "jetzig",
        .root_source_file = b.path("src/jetzig.zig"),
        .target = target,
        .optimize = optimize,
    });

    const mime_module = try GenerateMimeTypes.generateMimeModule(b);

    const zig_args_dep = b.dependency("args", .{ .target = target, .optimize = optimize });
    const jetzig_module = b.addModule("jetzig", .{ .root_source_file = b.path("src/jetzig.zig") });
    jetzig_module.addImport("mime_types", mime_module);
    lib.root_module.addImport("jetzig", jetzig_module);

    const zmpl_dep = b.dependency(
        "zmpl",
        .{
            .target = target,
            .optimize = optimize,
            .use_llvm = b.option(bool, "use_llvm", "Use LLVM") orelse use_llvm_default,
            .zmpl_templates_paths = templates_paths,
            .zmpl_auto_build = false,
            .zmpl_markdown_fragments = try generateMarkdownFragments(b),
            .zmpl_constants = try zmpl_build.addTemplateConstants(b, struct {
                jetzig_view: []const u8,
                jetzig_action: []const u8,
            }),
        },
    );

    const zmpl_steps = zmpl_dep.builder.top_level_steps;
    const zmpl_compile_step = zmpl_steps.get("compile").?;
    const compile_step = b.step("compile", "Compile Zmpl templates");
    compile_step.dependOn(&zmpl_compile_step.step);

    const zmpl_module = zmpl_dep.module("zmpl");

    const jetkv_dep = b.dependency("jetkv", .{ .target = target, .optimize = optimize });
    const jetquery_dep = b.dependency("jetquery", .{
        .target = target,
        .optimize = optimize,
        .jetquery_migrations_path = @as([]const u8, "src/app/database/migrations"),
        .jetquery_config_path = @as([]const u8, "config/database.zig"),
    });
    const jetcommon_dep = b.dependency("jetcommon", .{ .target = target, .optimize = optimize });
    const zmd_dep = b.dependency("zmd", .{ .target = target, .optimize = optimize });
    const httpz_dep = b.dependency("httpz", .{ .target = target, .optimize = optimize });

    // This is the way to make it look nice in the zig build script
    // If we would do it the other way around, we would have to do
    // b.dependency("jetzig",.{}).builder.dependency("zmpl",.{}).module("zmpl");
    b.modules.put("zmpl", zmpl_dep.module("zmpl")) catch @panic("Out of memory");
    b.modules.put("zmd", zmd_dep.module("zmd")) catch @panic("Out of memory");
    b.modules.put("jetquery", jetquery_dep.module("jetquery")) catch @panic("Out of memory");
    b.modules.put("jetcommon", jetcommon_dep.module("jetcommon")) catch @panic("Out of memory");
    b.modules.put("jetquery_migrate", jetquery_dep.module("jetquery_migrate")) catch @panic("Out of memory");

    const smtp_client_dep = b.dependency("smtp_client", .{
        .target = target,
        .optimize = optimize,
    });

    lib.root_module.addImport("zmpl", zmpl_module);
    jetzig_module.addImport("zmpl", zmpl_module);
    jetzig_module.addImport("args", zig_args_dep.module("args"));
    jetzig_module.addImport("zmd", zmd_dep.module("zmd"));
    jetzig_module.addImport("jetkv", jetkv_dep.module("jetkv"));
    jetzig_module.addImport("jetquery", jetquery_dep.module("jetquery"));
    jetzig_module.addImport("jetcommon", jetcommon_dep.module("jetcommon"));
    jetzig_module.addImport("smtp", smtp_client_dep.module("smtp_client"));
    jetzig_module.addImport("httpz", httpz_dep.module("httpz"));

    const main_tests = b.addTest(.{
        .root_source_file = b.path("src/tests.zig"),
        .target = target,
        .optimize = optimize,
    });

    const docs_step = b.step("docs", "Generate documentation");
    const docs_install = b.addInstallDirectory(.{
        .source_dir = lib.getEmittedDocs(),
        .install_dir = .prefix,
        .install_subdir = "docs",
    });

    docs_step.dependOn(&docs_install.step);

    main_tests.root_module.addImport("zmpl", zmpl_dep.module("zmpl"));
    main_tests.root_module.addImport("jetkv", jetkv_dep.module("jetkv"));
    main_tests.root_module.addImport("jetquery", jetquery_dep.module("jetquery"));
    main_tests.root_module.addImport("jetcommon", jetcommon_dep.module("jetcommon"));
    main_tests.root_module.addImport("httpz", httpz_dep.module("httpz"));
    main_tests.root_module.addImport("smtp", smtp_client_dep.module("smtp_client"));
    const test_build_options = b.addOptions();
    test_build_options.addOption(Environment, "environment", .testing);
    test_build_options.addOption(bool, "build_static", true);
    test_build_options.addOption(bool, "debug_console", false);
    const run_main_tests = b.addRunArtifact(main_tests);
    main_tests.root_module.addOptions("build_options", test_build_options);

    const test_step = b.step("test", "Run library tests");
    test_step.dependOn(&run_main_tests.step);
}

/// Build-time options for Jetzig.
pub const JetzigInitOptions = struct {
    zmpl_version: enum { v1, v2 } = .v2,
};

pub fn jetzigInit(b: *std.Build, exe: *std.Build.Step.Compile, options: JetzigInitOptions) !void {
    if (options.zmpl_version == .v1) {
        std.debug.print("Zmpl v1 has now been removed. Please upgrade to v2.\n", .{});
        return error.ZmplVersionNotSupported;
    }

    const target = exe.root_module.resolved_target orelse @panic("Unable to detect compile target.");
    const optimize = exe.root_module.optimize orelse .Debug;

    exe.use_llvm = exe.use_llvm orelse use_llvm_default;

    if (optimize != .Debug) exe.linkLibC();

    const environment = b.option(
        Environment,
        "environment",
        "Jetzig server environment.",
    ) orelse .development;

    const build_static = b.option(
        bool,
        "build_static",
        "Pre-render static routes. [default: false in development, true in testing/production]",
    ) orelse (environment != .development);

    const debug_console = b.option(
        bool,
        "debug_console",
        "Render a debug console on error. Default: false.",
    ) orelse false;

    if (debug_console == true and environment != .development) {
        std.debug.print("Environment must be `development` when `debug_console` is enabled.", .{});
        return error.JetzigBuildError;
    }

    const jetzig_dep = b.dependency(
        "jetzig",
        .{ .optimize = optimize, .target = target },
    );

    const jetquery_dep = jetzig_dep.builder.dependency("jetquery", .{
        .target = target,
        .optimize = optimize,
        .jetquery_migrations_path = @as([]const u8, "src/app/database/migrations"),
        .jetquery_config_path = @as([]const u8, "config/database.zig"),
    });

    const jetzig_module = jetzig_dep.module("jetzig");
    const zmpl_module = jetzig_dep.module("zmpl");
    const zmd_module = jetzig_dep.module("zmd");
    const jetquery_module = jetzig_dep.module("jetquery");
    const jetcommon_module = jetzig_dep.module("jetcommon");
    const jetquery_migrate_module = jetzig_dep.module("jetquery_migrate");
    const jetquery_reflect_module = jetquery_dep.module("jetquery_reflect");

    const build_options = b.addOptions();
    build_options.addOption(Environment, "environment", environment);
    build_options.addOption(bool, "build_static", build_static);
    build_options.addOption(bool, "debug_console", debug_console);
    jetzig_module.addOptions("build_options", build_options);

    exe.root_module.addImport("jetzig", jetzig_module);
    exe.root_module.addImport("zmpl", zmpl_module);
    exe.root_module.addImport("zmd", zmd_module);

    if (b.option(bool, "jetzig_runner", "Used internally by `jetzig server` command.")) |jetzig_runner| {
        if (jetzig_runner) {
            const file = try std.fs.cwd().createFile(".jetzig", .{ .truncate = true });
            defer file.close();
            try file.writeAll(exe.name);
        }
    }

    const root_path = if (b.build_root.path) |build_root_path|
        try std.fs.path.join(b.allocator, &.{ build_root_path, "." })
    else
        try std.fs.cwd().realpathAlloc(b.allocator, ".");
    const templates_path: []const u8 = try std.fs.path.join(
        b.allocator,
        &[_][]const u8{ root_path, "src", "app" },
    );
    const views_path: []const u8 = try std.fs.path.join(
        b.allocator,
        &[_][]const u8{ root_path, "src", "app", "views" },
    );
    const jobs_path = try std.fs.path.join(
        b.allocator,
        &[_][]const u8{ root_path, "src", "app", "jobs" },
    );
    const mailers_path = try std.fs.path.join(
        b.allocator,
        &[_][]const u8{ root_path, "src", "app", "mailers" },
    );

    const exe_routes_file = b.addExecutable(.{
        .name = "routes",
        .root_source_file = jetzig_dep.path("src/routes_file.zig"),
        .target = target,
        .optimize = optimize,
        .use_llvm = exe.use_llvm,
    });

    exe_routes_file.root_module.addImport("jetzig", jetzig_module);
    exe_routes_file.root_module.addImport("jetkv", jetzig_module);
    exe_routes_file.root_module.addImport("httpz", jetzig_module);
    exe_routes_file.root_module.addImport("zmpl", zmpl_module);

    const run_routes_file_cmd = b.addRunArtifact(exe_routes_file);
    const routes_file_path = run_routes_file_cmd.addOutputFileArg("routes.zig");
    run_routes_file_cmd.addArgs(&.{
        root_path,
        b.pathFromRoot("src"),
        templates_path,
        views_path,
        jobs_path,
        mailers_path,
    });

    const routes_module = b.createModule(.{ .root_source_file = routes_file_path });
    routes_module.addImport("jetzig", jetzig_module);
    exe.root_module.addImport("routes", routes_module);

    const exe_static_routes = b.addExecutable(.{
        .name = "static",
        .root_source_file = jetzig_dep.path("src/compile_static_routes.zig"),
        .target = target,
        .optimize = optimize,
        .use_llvm = exe.use_llvm,
    });

    const main_module = b.createModule(.{ .root_source_file = b.path("src/main.zig") });
    exe_static_routes.root_module.addImport("routes", routes_module);
    exe_static_routes.root_module.addImport("jetzig", jetzig_module);
    exe_static_routes.root_module.addImport("zmpl", zmpl_module);
    exe_static_routes.root_module.addImport("main", main_module);

    const schema_module = if (try isSourceFile(b, "src/app/database/Schema.zig"))
        b.createModule(.{ .root_source_file = b.path("src/app/database/Schema.zig") })
    else
        jetzig_dep.builder.createModule(
            .{ .root_source_file = jetzig_dep.builder.path("src/jetzig/DefaultSchema.zig") },
        );
    exe_static_routes.root_module.addImport("Schema", schema_module);
    exe.root_module.addImport("Schema", schema_module);

    schema_module.addImport("jetzig", jetzig_module);

    exe_static_routes.root_module.addImport("routes", routes_module);
    exe_static_routes.root_module.addImport("jetzig", jetzig_module);
    exe_static_routes.root_module.addImport("zmpl", zmpl_module);

    const markdown_fragments_write_files = b.addWriteFiles();
    const path = markdown_fragments_write_files.add(
        "markdown_fragments.zig",
        try generateMarkdownFragments(b),
    );
    const markdown_fragments_module = b.createModule(.{ .root_source_file = path });
    exe_static_routes.root_module.addImport("markdown_fragments", markdown_fragments_module);

    const run_static_routes_cmd = b.addRunArtifact(exe_static_routes);
    const static_outputs_path = run_static_routes_cmd.addOutputFileArg("static.zig");
    const static_module = if (build_static)
        b.createModule(.{ .root_source_file = static_outputs_path })
    else
        b.createModule(.{
            .root_source_file = jetzig_dep.builder.path("src/jetzig/development_static.zig"),
        });

    exe.root_module.addImport("static", static_module);
    run_static_routes_cmd.expectExitCode(0);

    const run_tests_file_cmd = b.addRunArtifact(exe_routes_file);
    run_tests_file_cmd.step.dependOn(&run_routes_file_cmd.step);

    const tests_file_path = run_tests_file_cmd.addOutputFileArg("tests.zig");

    run_tests_file_cmd.addArgs(&.{
        root_path,
        b.pathFromRoot("src"),
        templates_path,
        views_path,
        jobs_path,
        mailers_path,
        try randomSeed(b), // Hack to force cache skip - let's find a better way.
    });

    for (try scanSourceFiles(b)) |sub_path| {
        // XXX: We don't use these args, but they help Zig's build system to cache/bust steps.
        run_routes_file_cmd.addFileArg(.{ .src_path = .{ .owner = b, .sub_path = sub_path } });
        run_tests_file_cmd.addFileArg(.{ .src_path = .{ .owner = b, .sub_path = sub_path } });
    }

    const exe_unit_tests = b.addTest(.{
        .root_source_file = tests_file_path,
        .target = target,
        .optimize = optimize,
        .test_runner = .{ .mode = .simple, .path = jetzig_dep.path("src/test_runner.zig") },
    });
    exe_unit_tests.root_module.addImport("jetzig", jetzig_module);
    exe_unit_tests.root_module.addImport("static", static_module);
    exe_unit_tests.root_module.addImport("routes", routes_module);
    exe_unit_tests.root_module.addImport("main", main_module);

    var it = exe.root_module.import_table.iterator();
    while (it.next()) |import| {
        if (std.mem.eql(u8, import.key_ptr.*, "static")) continue;

        routes_module.addImport(import.key_ptr.*, import.value_ptr.*);
        exe_static_routes.root_module.addImport(import.key_ptr.*, import.value_ptr.*);
        exe_unit_tests.root_module.addImport(import.key_ptr.*, import.value_ptr.*);
        main_module.addImport(import.key_ptr.*, import.value_ptr.*);
    }

    if (exe.root_module.link_libc == true) {
        exe_static_routes.linkLibC();
        exe_unit_tests.linkLibC();
    }

    for (exe.root_module.link_objects.items) |link_object| {
        try exe_static_routes.root_module.link_objects.append(b.allocator, link_object);
        try exe_unit_tests.root_module.link_objects.append(b.allocator, link_object);
        try main_module.link_objects.append(b.allocator, link_object);
    }

    const run_exe_unit_tests = b.addRunArtifact(exe_unit_tests);
    const test_step = b.step("jetzig:test", "Run tests");
    test_step.dependOn(&run_exe_unit_tests.step);
    run_exe_unit_tests.step.dependOn(&run_static_routes_cmd.step);
    run_exe_unit_tests.step.dependOn(&run_routes_file_cmd.step);

    const routes_step = b.step("jetzig:routes", "List all routes in your app");
    const exe_routes = b.addExecutable(.{
        .name = "routes",
        .root_source_file = jetzig_dep.path("src/commands/routes.zig"),
        .target = target,
        .optimize = optimize,
        .use_llvm = exe.use_llvm,
    });

    const auth_user_create_step = b.step("jetzig:auth:user:create", "List all routes in your app");
    const exe_auth = b.addExecutable(.{
        .name = "auth",
        .root_source_file = jetzig_dep.path("src/commands/auth.zig"),
        .target = target,
        .optimize = optimize,
        .use_llvm = exe.use_llvm,
    });
    exe_auth.root_module.addImport("jetquery", jetquery_module);
    exe_auth.root_module.addImport("jetzig", jetzig_module);
    exe_auth.root_module.addImport("jetcommon", jetcommon_module);
    exe_auth.root_module.addImport("Schema", schema_module);
    exe_auth.root_module.addImport("main", main_module);
    const run_auth_user_create_cmd = b.addRunArtifact(exe_auth);
    auth_user_create_step.dependOn(&run_auth_user_create_cmd.step);
    run_auth_user_create_cmd.addArg("user:create");
    if (b.option([]const u8, "auth_username", "Auth username")) |username| {
        run_auth_user_create_cmd.addArg(username);
    }
    if (b.option([]const u8, "auth_password", "Auth password")) |password| {
        run_auth_user_create_cmd.addArg(password);
    }

    const exe_database = b.addExecutable(.{
        .name = "database",
        .root_source_file = jetzig_dep.path("src/commands/database.zig"),
        .target = target,
        .optimize = optimize,
        .use_llvm = exe.use_llvm,
    });
    exe_database.root_module.addImport("jetquery", jetquery_module);
    exe_database.root_module.addImport("jetzig", jetzig_module);
    exe_database.root_module.addImport("jetcommon", jetcommon_module);
    exe_database.root_module.addImport("jetquery_migrate", jetquery_migrate_module);
    exe_database.root_module.addImport("jetquery_reflect", jetquery_reflect_module);
    exe_database.root_module.addImport("Schema", schema_module);

    registerDatabaseSteps(b, exe_database);

    const option_db_exe = b.option(bool, "database_exe", "option to install 'database' executable default is false") orelse false;
    if (option_db_exe) b.installArtifact(exe_database);

    exe_routes.root_module.addImport("jetzig", jetzig_module);
    exe_routes.root_module.addImport("routes", routes_module);
    exe_routes.root_module.addImport("app", exe.root_module);
    const run_routes_cmd = b.addRunArtifact(exe_routes);
    routes_step.dependOn(&run_routes_cmd.step);
}

fn registerDatabaseSteps(b: *std.Build, exe_database: *std.Build.Step.Compile) void {
    const commands = .{
        .{ "migrate", "Migrate your Jetzig app's database." },
        .{ "rollback", "Roll back a migration in your Jetzig app's database." },
        .{ "create", "Create a database for your Jetzig app." },
        .{ "drop", "Drop your Jetzig app's database." },
        .{ "reflect", "Read your app's database and generate a JetQuery schema." },
    };

    inline for (commands) |command| {
        const action = command[0];
        const description = command[1];
        const step = b.step("jetzig:database:" ++ action, description);
        const run_cmd = b.addRunArtifact(exe_database);
        run_cmd.addArg(action);
        step.dependOn(&run_cmd.step);
    }
}

fn generateMarkdownFragments(b: *std.Build) ![]const u8 {
    const file = std.fs.cwd().openFile(b.pathJoin(&.{ "src", "main.zig" }), .{}) catch |err| {
        switch (err) {
            error.FileNotFound => return "",
            else => return err,
        }
    };
    const stat = try file.stat();
    const source = try file.readToEndAllocOptions(b.allocator, @intCast(stat.size), null, @alignOf(u8), 0);
    if (try getMarkdownFragmentsSource(b.allocator, source)) |markdown_fragments_source| {
        return try std.fmt.allocPrint(b.allocator,
            \\const std = @import("std");
            \\const zmd = @import("zmd");
            \\
            \\{s};
            \\
        , .{markdown_fragments_source});
    } else {
        return "";
    }
}

fn getMarkdownFragmentsSource(allocator: std.mem.Allocator, source: [:0]const u8) !?[]const u8 {
    var ast = try std.zig.Ast.parse(allocator, source, .zig);
    defer ast.deinit(allocator);

    for (ast.nodes.items(.tag), 0..) |tag, index| {
        switch (tag) {
            .simple_var_decl => {
                const decl = ast.simpleVarDecl(@intCast(index));
                const identifier = ast.tokenSlice(decl.ast.mut_token + 1);
                if (std.mem.eql(u8, identifier, "markdown_fragments")) {
                    return ast.getNodeSource(@intCast(index));
                }
            },
            else => continue,
        }
    }

    return null;
}

fn isSourceFile(b: *std.Build, path: []const u8) !bool {
    const dir = try std.fs.openDirAbsolute(b.build_root.path.?, .{});
    const stat = dir.statFile(path) catch |err| {
        switch (err) {
            error.FileNotFound => return false,
            else => return err,
        }
    };
    return stat.kind == .file;
}

fn scanSourceFiles(b: *std.Build) ![]const []const u8 {
    var buf = std.ArrayList([]const u8).init(b.allocator);

    var src_dir = try std.fs.openDirAbsolute(b.pathFromRoot("src"), .{ .iterate = true });
    defer src_dir.close();

    var walker = try src_dir.walk(b.allocator);
    defer walker.deinit();

    while (try walker.next()) |entry| {
        if (entry.kind == .file) try buf.append(
            try std.fs.path.join(b.allocator, &.{ "src", entry.path }),
        );
    }
    return try buf.toOwnedSlice();
}

fn randomSeed(b: *std.Build) ![]const u8 {
    const seed = try b.allocator.alloc(u8, 32);
    const chars = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
    for (0..32) |index| {
        seed[index] = chars[std.crypto.random.intRangeAtMost(u8, 0, chars.len - 1)];
    }

    return seed;
}