#!/usr/bin/env python

import os
import platform
import sys
import subprocess
from binding_generator import scons_generate_bindings, scons_emit_files
from SCons.Errors import UserError

EnsureSConsVersion(4, 0)


def add_sources(sources, dir, extension):
    for f in os.listdir(dir):
        if f.endswith("." + extension):
            sources.append(dir + "/" + f)


def normalize_path(val):
    return val if os.path.isabs(val) else os.path.join(env.Dir("#").abspath, val)


def validate_api_file(key, val, env):
    if not os.path.isfile(normalize_path(val)):
        raise UserError("GDExtension API file ('%s') does not exist: %s" % (key, val))


def validate_gdextension_dir(key, val, env):
    if not os.path.isdir(normalize_path(val)):
        raise UserError("GDExtension directory ('%s') does not exist: %s" % (key, val))


def get_gdextension_dir(env):
    return normalize_path(env.get("gdextension_dir", env.Dir("gdextension").abspath))


def get_api_file(env):
    return normalize_path(env.get("custom_api_file", os.path.join(get_gdextension_dir(env), "extension_api.json")))


# Try to detect the host platform automatically.
# This is used if no `platform` argument is passed
if sys.platform.startswith("linux"):
    default_platform = "linux"
elif sys.platform == "darwin":
    default_platform = "macos"
elif sys.platform == "win32" or sys.platform == "msys":
    default_platform = "windows"
elif ARGUMENTS.get("platform", ""):
    default_platform = ARGUMENTS.get("platform")
else:
    raise ValueError("Could not detect platform automatically, please specify with platform=<platform>")

# Default tools with no platform defaults to gnu toolchain.
# We apply platform specific toolchains via our custom tools.
env = Environment(tools=["default"], PLATFORM="")

# Default num_jobs to local cpu count if not user specified.
# SCons has a peculiarity where user-specified options won't be overridden
# by SetOption, so we can rely on this to know if we should use our default.
initial_num_jobs = env.GetOption("num_jobs")
altered_num_jobs = initial_num_jobs + 1
env.SetOption("num_jobs", altered_num_jobs)
if env.GetOption("num_jobs") == altered_num_jobs:
    cpu_count = os.cpu_count()
    if cpu_count is None:
        print("Couldn't auto-detect CPU count to configure build parallelism. Specify it with the -j argument.")
    else:
        safer_cpu_count = cpu_count if cpu_count <= 4 else cpu_count - 1
        print(
            "Auto-detected %d CPU cores available for build parallelism. Using %d cores by default. You can override it with the -j argument."
            % (cpu_count, safer_cpu_count)
        )
        env.SetOption("num_jobs", safer_cpu_count)

# Custom options and profile flags.
customs = ["custom.py"]
profile = ARGUMENTS.get("profile", "")
if profile:
    if os.path.isfile(profile):
        customs.append(profile)
    elif os.path.isfile(profile + ".py"):
        customs.append(profile + ".py")
opts = Variables(customs, ARGUMENTS)

platforms = ("linux", "macos", "windows", "android", "ios", "javascript")
opts.Add(
    EnumVariable(
        "platform",
        "Target platform",
        default_platform,
        allowed_values=platforms,
        ignorecase=2,
    )
)

# Editor and template_debug are compatible (i.e. you can use the same binary for Godot editor builds and Godot debug templates).
# Godot release templates are only compatible with "template_release" builds.
# For this reason, we default to template_debug builds, unlike Godot which defaults to editor builds.
opts.Add(
    EnumVariable("target", "Compilation target", "template_debug", ("editor", "template_release", "template_debug"))
)
opts.Add(
    PathVariable(
        "gdextension_dir",
        "Path to a custom directory containing GDExtension interface header and API JSON file",
        None,
        validate_gdextension_dir,
    )
)
opts.Add(
    PathVariable(
        "custom_api_file",
        "Path to a custom GDExtension API JSON file (takes precedence over `gdextension_dir`)",
        None,
        validate_api_file,
    )
)
opts.Add(
    BoolVariable("generate_bindings", "Force GDExtension API bindings generation. Auto-detected by default.", False)
)
opts.Add(BoolVariable("generate_template_get_node", "Generate a template version of the Node class's get_node.", True))

opts.Add(BoolVariable("build_library", "Build the godot-cpp library.", True))
opts.Add(EnumVariable("precision", "Set the floating-point precision level", "single", ("single", "double")))

# Add platform options
tools = {}
for pl in platforms:
    tool = Tool(pl, toolpath=["tools"])
    if hasattr(tool, "options"):
        tool.options(opts)
    tools[pl] = tool

# CPU architecture options.
architecture_array = ["", "universal", "x86_32", "x86_64", "arm32", "arm64", "rv64", "ppc32", "ppc64", "wasm32"]
architecture_aliases = {
    "x64": "x86_64",
    "amd64": "x86_64",
    "armv7": "arm32",
    "armv8": "arm64",
    "arm64v8": "arm64",
    "aarch64": "arm64",
    "rv": "rv64",
    "riscv": "rv64",
    "riscv64": "rv64",
    "ppcle": "ppc32",
    "ppc": "ppc32",
    "ppc64le": "ppc64",
}
opts.Add(EnumVariable("arch", "CPU architecture", "", architecture_array, architecture_aliases))

# Targets flags tool (optimizations, debug symbols)
target_tool = Tool("targets", toolpath=["tools"])
target_tool.options(opts)

opts.Update(env)
Help(opts.GenerateHelpText(env))

# Process CPU architecture argument.
if env["arch"] == "":
    # No architecture specified. Default to arm64 if building for Android,
    # universal if building for macOS or iOS, wasm32 if building for web,
    # otherwise default to the host architecture.
    if env["platform"] in ["macos", "ios"]:
        env["arch"] = "universal"
    elif env["platform"] == "android":
        env["arch"] = "arm64"
    elif env["platform"] == "javascript":
        env["arch"] = "wasm32"
    else:
        host_machine = platform.machine().lower()
        if host_machine in architecture_array:
            env["arch"] = host_machine
        elif host_machine in architecture_aliases.keys():
            env["arch"] = architecture_aliases[host_machine]
        elif "86" in host_machine:
            # Catches x86, i386, i486, i586, i686, etc.
            env["arch"] = "x86_32"
        else:
            print("Unsupported CPU architecture: " + host_machine)
            Exit()

tool = Tool(env["platform"], toolpath=["tools"])

if tool is None or not tool.exists(env):
    raise ValueError("Required toolchain not found for platform " + env["platform"])

tool.generate(env)
target_tool.generate(env)

# Detect and print a warning listing unknown SCons variables to ease troubleshooting.
unknown = opts.UnknownVariables()
if unknown:
    print("WARNING: Unknown SCons variables were passed and will be ignored:")
    for item in unknown.items():
        print("    " + item[0] + "=" + item[1])

print("Building for architecture " + env["arch"] + " on platform " + env["platform"])

# Require C++17
if env.get("is_msvc", False):
    env.Append(CXXFLAGS=["/std:c++17"])
else:
    env.Append(CXXFLAGS=["-std=c++17"])

if env["precision"] == "double":
    env.Append(CPPDEFINES=["REAL_T_IS_DOUBLE"])

# Generate bindings
env.Append(BUILDERS={"GenerateBindings": Builder(action=scons_generate_bindings, emitter=scons_emit_files)})

bindings = env.GenerateBindings(
    env.Dir("."),
    [get_api_file(env), os.path.join(get_gdextension_dir(env), "gdextension_interface.h"), "binding_generator.py"],
)

scons_cache_path = os.environ.get("SCONS_CACHE")
if scons_cache_path is not None:
    CacheDir(scons_cache_path)
    Decider("MD5")

# Forces bindings regeneration.
if env["generate_bindings"]:
    AlwaysBuild(bindings)
    NoCache(bindings)

# Includes
env.Append(CPPPATH=[[env.Dir(d) for d in [get_gdextension_dir(env), "include", os.path.join("gen", "include")]]])

# Sources to compile
sources = []
add_sources(sources, "src", "cpp")
add_sources(sources, "src/classes", "cpp")
add_sources(sources, "src/core", "cpp")
add_sources(sources, "src/variant", "cpp")
sources.extend([f for f in bindings if str(f).endswith(".cpp")])

suffix = ".{}.{}".format(env["platform"], env["target"])
if env.dev_build:
    suffix += ".dev"
if env["precision"] == "double":
    suffix += ".double"
suffix += "." + env["arch"]
if env["ios_simulator"]:
    suffix += ".simulator"

# Expose it when included from another project
env["suffix"] = suffix

library = None
env["OBJSUFFIX"] = suffix + env["OBJSUFFIX"]
library_name = "libgodot-cpp{}{}".format(suffix, env["LIBSUFFIX"])

if env["build_library"]:
    library = env.StaticLibrary(target=env.File("bin/%s" % library_name), source=sources)
    Default(library)

env.Append(LIBPATH=[env.Dir("bin")])
env.Append(LIBS=library_name)
Return("env")