# Copyright 2017 The Bazel Authors. All rights reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#    http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

"TypeScript compilation"

# pylint: disable=unused-argument
# pylint: disable=missing-docstring
load(":common/compilation.bzl", "COMMON_ATTRIBUTES", "compile_ts", "ts_providers_dict_to_struct")
load(":common/tsconfig.bzl", "create_tsconfig")
load(":ts_config.bzl", "TsConfigInfo")

def _compile_action(ctx, inputs, outputs, tsconfig_file, node_opts, description = "prodmode"):
    externs_files = []
    action_outputs = []
    for output in outputs:
        if output.basename.endswith(".externs.js"):
            externs_files.append(output)
        elif output.basename.endswith(".es5.MF"):
            ctx.actions.write(output, content = "")
        else:
            action_outputs.append(output)

    # TODO(plf): For now we mock creation of files other than {name}.js.
    for externs_file in externs_files:
        ctx.actions.write(output = externs_file, content = "")

    # A ts_library that has only .d.ts inputs will have no outputs,
    # therefore there are no actions to execute
    if not action_outputs:
        return struct()

    action_inputs = inputs + [
        f
        for f in ctx.files.node_modules
        if f.path.endswith(".js") or f.path.endswith(".ts") or f.path.endswith(".json")
    ]
    if ctx.file.tsconfig:
        action_inputs += [ctx.file.tsconfig]
        if TsConfigInfo in ctx.attr.tsconfig:
            action_inputs += ctx.attr.tsconfig[TsConfigInfo].deps

    # Pass actual options for the node binary in the special "--node_options" argument.
    arguments = ["--node_options=%s" % opt for opt in node_opts]

    # One at-sign makes this a params-file, enabling the worker strategy.
    # Two at-signs escapes the argument so it's passed through to tsc_wrapped
    # rather than the contents getting expanded.
    if ctx.attr.supports_workers:
        arguments.append("@@" + tsconfig_file.path)
        mnemonic = "TypeScriptCompile"
    else:
        arguments.append("-p")
        arguments.append(tsconfig_file.path)
        mnemonic = "tsc"

    ctx.actions.run(
        progress_message = "Compiling TypeScript (%s) %s" % (description, ctx.label),
        mnemonic = mnemonic,
        inputs = action_inputs,
        outputs = action_outputs,
        # Use the built-in shell environment
        # Allow for users who set a custom shell that can locate standard binaries like tr and uname
        # See https://github.com/NixOS/nixpkgs/issues/43955#issuecomment-407546331
        use_default_shell_env = True,
        arguments = arguments,
        executable = ctx.executable.compiler,
        execution_requirements = {
            "supports-workers": str(int(ctx.attr.supports_workers)),
        },
    )

    # Enable the replay_params in case an aspect needs to re-build this library.
    return struct(
        label = ctx.label,
        tsconfig = tsconfig_file,
        inputs = action_inputs,
        outputs = action_outputs,
        compiler = ctx.executable.compiler,
    )

def _devmode_compile_action(ctx, inputs, outputs, tsconfig_file, node_opts):
    _compile_action(
        ctx,
        inputs,
        outputs,
        tsconfig_file,
        node_opts,
        description = "devmode",
    )

def tsc_wrapped_tsconfig(
        ctx,
        files,
        srcs,
        devmode_manifest = None,
        jsx_factory = None,
        **kwargs):
    """Produce a tsconfig.json that sets options required under Bazel.
    """

    # The location of tsconfig.json is interpreted as the root of the project
    # when it is passed to the TS compiler with the `-p` option:
    #   https://www.typescriptlang.org/docs/handbook/tsconfig-json.html.
    # Our tsconfig.json is in bazel-foo/bazel-out/local-fastbuild/bin/{package_path}
    # because it's generated in the execution phase. However, our source files are in
    # bazel-foo/ and therefore we need to strip some parent directories for each
    # f.path.

    config = create_tsconfig(
        ctx,
        files,
        srcs,
        devmode_manifest = devmode_manifest,
        **kwargs
    )
    config["bazelOptions"]["nodeModulesPrefix"] = "/".join([p for p in [
        ctx.attr.node_modules.label.workspace_root,
        ctx.attr.node_modules.label.package,
        "node_modules",
    ] if p])

    # If the user gives a tsconfig attribute, the generated file should extend
    # from the user's tsconfig.
    # See https://github.com/Microsoft/TypeScript/issues/9876
    # We subtract the ".json" from the end before handing to TypeScript because
    # this gives extra error-checking.
    if ctx.file.tsconfig:
        workspace_path = config["compilerOptions"]["rootDir"]
        config["extends"] = "/".join([workspace_path, ctx.file.tsconfig.path[:-len(".json")]])

    if jsx_factory:
        config["compilerOptions"]["jsxFactory"] = jsx_factory

    return config

# ************ #
# ts_library   #
# ************ #

def _ts_library_impl(ctx):
    """Implementation of ts_library.

    Args:
      ctx: the context.

    Returns:
      the struct returned by the call to compile_ts.
    """
    ts_providers = compile_ts(
        ctx,
        is_library = True,
        compile_action = _compile_action,
        devmode_compile_action = _devmode_compile_action,
        tsc_wrapped_tsconfig = tsc_wrapped_tsconfig,
    )
    return ts_providers_dict_to_struct(ts_providers)

ts_library = rule(
    _ts_library_impl,
    attrs = dict(COMMON_ATTRIBUTES, **{
        "srcs": attr.label_list(
            doc = "The TypeScript source files to compile.",
            allow_files = [".ts", ".tsx"],
            mandatory = True,
        ),

        # TODO(alexeagle): reconcile with google3: ts_library rules should
        # be portable across internal/external, so we need this attribute
        # internally as well.
        "tsconfig": attr.label(
            doc = """A tsconfig.json file containing settings for TypeScript compilation.
            Note that some properties in the tsconfig are governed by Bazel and will be
            overridden, such as `target` and `module`.

            The default value is set to `//:tsconfig.json` by a macro. This means you must
            either:

            - Have your `tsconfig.json` file in the workspace root directory
            - Use an alias in the root BUILD.bazel file to point to the location of tsconfig:
              `alias(name="tsconfig.json", actual="//path/to:tsconfig-something.json")`
            - Give an explicit `tsconfig` attribute to all `ts_library` targets
            """,
            allow_single_file = True,
        ),
        "compiler": attr.label(
            doc = """Intended for internal use only.
            Sets a different TypeScript compiler binary to use for this library.
            For example, we use the vanilla TypeScript tsc.js for bootstrapping,
            and Angular compilations can replace this with `ngc`.""",
            default = Label("//internal:tsc_wrapped_bin"),
            allow_files = True,
            executable = True,
            cfg = "host",
        ),
        "supports_workers": attr.bool(
            doc = """Intended for internal use only.
            Allows you to disable the Bazel Worker strategy for this library.
            Typically used together with the "compiler" setting when using a
            non-worker aware compiler binary.""",
            default = True,
        ),
        "tsickle_typed": attr.bool(default = True),
        "internal_testing_type_check_dependencies": attr.bool(default = False, doc = "Testing only, whether to type check inputs that aren't srcs."),
        # @// is special syntax for the "main" repository
        # The default assumes the user specified a target "node_modules" in their
        # root BUILD file.
        "node_modules": attr.label(default = Label("@//:node_modules")),
    }),
    outputs = {
        "tsconfig": "%{name}_tsconfig.json",
    },
)
"""
`ts_library` type-checks and compiles a set of TypeScript sources to JavaScript.

It produces declarations files (`.d.ts`) which are used for compiling downstream
TypeScript targets and JavaScript for the browser and Closure compiler.
"""

def ts_library_macro(tsconfig = None, **kwargs):
    """Wraps `ts_library` to set the default for the `tsconfig` attribute.

    This must be a macro so that the string is converted to a label in the context of the
    workspace that declares the `ts_library` target, rather than the workspace that defines
    `ts_library`, or the workspace where the build is taking place.

    This macro is re-exported as `ts_library` in the public API.

    Args:
      tsconfig: the label pointing to a tsconfig.json file
      **kwargs: remaining args to pass to the ts_library rule
    """
    if not tsconfig:
        tsconfig = "//:tsconfig.json"

    ts_library(tsconfig = tsconfig, **kwargs)