#!/usr/bin/env python3

"""
This script should use a very simple, functional programming style.
Avoid Jinja macros in favor of native Python functions.

Don't go overboard on code generation; use Python only to generate
content that can't be easily declared statically using CircleCI's YAML API.

Data declarations (e.g. the nested loops for defining the configuration matrix)
should be at the top of the file for easy updating.

See this comment for design rationale:
https://github.com/pytorch/vision/pull/1321#issuecomment-531033978
"""

import os.path

import jinja2
import yaml
from jinja2 import select_autoescape


PYTHON_VERSIONS = ["3.7", "3.8", "3.9", "3.10"]
CU_VERSIONS_DICT = {
    "linux": ["cpu", "cu102", "cu116", "cu117", "rocm5.1.1", "rocm5.2"],
    "windows": ["cpu", "cu116", "cu117"],
    "macos": ["cpu"],
}


DOC_VERSION = ("linux", "3.8")


def build_workflows(prefix="", upload=False, filter_branch=None, indentation=6):
    w = []
    w += build_download_job(filter_branch)
    for os_type in ["linux", "macos", "windows"]:
        w += build_ffmpeg_job(os_type, filter_branch)
    for btype in ["wheel", "conda"]:
        for os_type in ["linux", "macos", "windows"]:
            for python_version in PYTHON_VERSIONS:
                for cu_version in CU_VERSIONS_DICT[os_type]:
                    fb = filter_branch
                    if cu_version.startswith("rocm") and btype == "conda":
                        continue
                    if not fb and (
                        os_type == "linux" and btype == "wheel" and python_version == "3.8" and cu_version == "cpu"
                    ):
                        # the fields must match the build_docs "requires" dependency
                        fb = "/.*/"
                    w += build_workflow_pair(btype, os_type, python_version, cu_version, fb, prefix, upload)

    if not filter_branch:
        # Build on every pull request, but upload only on nightly and tags
        w += build_doc_job("/.*/")
        w += upload_doc_job("nightly")
        w += docstring_parameters_sync_job(None)

    return indent(indentation, w)


def build_download_job(filter_branch):
    job = {
        "name": "download_third_parties",
    }

    if filter_branch:
        job["filters"] = gen_filter_branch_tree(filter_branch)
    return [{"download_third_parties": job}]


def build_ffmpeg_job(os_type, filter_branch):
    job = {
        "name": f"build_ffmpeg_{os_type}",
        "requires": ["download_third_parties"],
    }

    if filter_branch:
        job["filters"] = gen_filter_branch_tree(filter_branch)
    job["python_version"] = "foo"
    return [{f"build_ffmpeg_{os_type}": job}]


def build_workflow_pair(btype, os_type, python_version, cu_version, filter_branch, prefix="", upload=False):

    w = []
    base_workflow_name = f"{prefix}binary_{os_type}_{btype}_py{python_version}_{cu_version}"
    w.append(generate_base_workflow(base_workflow_name, python_version, cu_version, filter_branch, os_type, btype))

    if upload:

        w.append(generate_upload_workflow(base_workflow_name, filter_branch, os_type, btype, cu_version))

    if os_type != "macos":
        pydistro = "pip" if btype == "wheel" else "conda"
        w.append(
            generate_smoketest_workflow(
                pydistro, base_workflow_name, filter_branch, python_version, cu_version, os_type
            )
        )

    return w


def build_doc_job(filter_branch):
    job = {
        "name": "build_docs",
        "python_version": "3.8",
        "cuda_version": "cu116",
        "requires": [
            "binary_linux_conda_py3.8_cu116",
        ],
    }

    if filter_branch:
        job["filters"] = gen_filter_branch_tree(filter_branch)
    return [{"build_docs": job}]


def upload_doc_job(filter_branch):
    job = {
        "name": "upload_docs",
        "context": "org-member",
        "python_version": "3.8",
        "requires": [
            "build_docs",
        ],
    }

    if filter_branch:
        job["filters"] = gen_filter_branch_tree(filter_branch)
    return [{"upload_docs": job}]


def docstring_parameters_sync_job(filter_branch):
    job = {
        "name": "docstring_parameters_sync",
        "python_version": "3.8",
        "requires": [
            "binary_linux_wheel_py3.8_cpu",
        ],
    }

    if filter_branch:
        job["filters"] = gen_filter_branch_tree(filter_branch)
    return [{"docstring_parameters_sync": job}]


def generate_base_workflow(base_workflow_name, python_version, cu_version, filter_branch, os_type, btype):

    d = {
        "name": base_workflow_name,
        "python_version": python_version,
        "cuda_version": cu_version,
        "requires": [f"build_ffmpeg_{os_type}"],
    }

    if btype == "conda":
        d["conda_docker_image"] = f'pytorch/conda-builder:{cu_version.replace("cu1","cuda1")}'
    elif cu_version.startswith("cu"):
        d["wheel_docker_image"] = f'pytorch/manylinux-{cu_version.replace("cu1","cuda1")}'
    elif cu_version.startswith("rocm"):
        d["wheel_docker_image"] = f"pytorch/manylinux-rocm:{cu_version[len('rocm'):]}"

    if filter_branch:
        d["filters"] = gen_filter_branch_tree(filter_branch)

    return {f"binary_{os_type}_{btype}": d}


def gen_filter_branch_tree(*branches):
    return {
        "branches": {
            "only": list(branches),
        },
        "tags": {
            # Using a raw string here to avoid having to escape
            # anything
            "only": r"/v[0-9]+(\.[0-9]+)*-rc[0-9]+/"
        },
    }


def generate_upload_workflow(base_workflow_name, filter_branch, os_type, btype, cu_version):
    d = {
        "name": "{base_workflow_name}_upload".format(base_workflow_name=base_workflow_name),
        "context": "org-member",
        "requires": [base_workflow_name],
    }

    if btype == "wheel":
        d["subfolder"] = "" if os_type == "macos" else cu_version + "/"

    if filter_branch:
        d["filters"] = gen_filter_branch_tree(filter_branch)

    return {"binary_{btype}_upload".format(btype=btype): d}


def generate_smoketest_workflow(pydistro, base_workflow_name, filter_branch, python_version, cu_version, os_type):

    smoke_suffix = f"smoke_test_{pydistro}".format(pydistro=pydistro)
    d = {
        "name": f"{base_workflow_name}_{smoke_suffix}",
        "requires": [base_workflow_name],
        "python_version": python_version,
        "cuda_version": cu_version,
    }

    if filter_branch:
        d["filters"] = gen_filter_branch_tree(filter_branch)

    smoke_name = f"smoke_test_{os_type}_{pydistro}"
    if pydistro == "conda" and (os_type == "linux" or os_type == "windows") and cu_version != "cpu":
        smoke_name += "_gpu"
    return {smoke_name: d}


def indent(indentation, data_list):
    return ("\n" + " " * indentation).join(yaml.dump(data_list).splitlines())


def unittest_python_versions(os):
    return {
        "windows": PYTHON_VERSIONS[:1],
        "macos": PYTHON_VERSIONS[:1],
        "linux": PYTHON_VERSIONS,
    }.get(os)


def unittest_workflows(indentation=6):
    jobs = []
    jobs += build_download_job(None)
    for os_type in ["linux", "windows", "macos"]:
        for device_type in ["cpu", "gpu"]:
            if os_type == "macos" and device_type == "gpu":
                continue

            for i, python_version in enumerate(unittest_python_versions(os_type)):
                job = {
                    "name": f"unittest_{os_type}_{device_type}_py{python_version}",
                    "python_version": python_version,
                    "cuda_version": "cpu" if device_type == "cpu" else "cu116",
                    "requires": ["download_third_parties"],
                }

                jobs.append({f"unittest_{os_type}_{device_type}": job})

                if i == 0 and os_type == "linux" and device_type == "cpu":
                    jobs.append(
                        {
                            "stylecheck": {
                                "name": f"stylecheck_py{python_version}",
                                "python_version": python_version,
                                "cuda_version": "cpu",
                            }
                        }
                    )
    return indent(indentation, jobs)


if __name__ == "__main__":
    d = os.path.dirname(__file__)
    env = jinja2.Environment(
        loader=jinja2.FileSystemLoader(d),
        lstrip_blocks=True,
        autoescape=select_autoescape(enabled_extensions=("html", "xml")),
    )

    with open(os.path.join(d, "config.yml"), "w") as f:
        f.write(
            env.get_template("config.yml.in").render(
                build_workflows=build_workflows,
                unittest_workflows=unittest_workflows,
            )
        )
        f.write("\n")
