wscript

#
# Beep — build rules for a Pebble app written completely in Zig.
#
# Instead of compiling C from src/c/, we compile Zig source files to ARM
# objects (matching the emery/obelix ABI) and hand the resulting .o files to
# the Pebble SDK's normal link step (pbl_build), which links them against
# libpebble and the generated app linker script to produce the .pbw.
#

import os.path

top = '.'
out = 'build'

# Path to the Zig compiler. Override with the ZIG environment variable.
ZIG = os.environ.get('ZIG', '/home/kanna/.local/zig/zig')

# Emery apps are Cortex-M3, Thumb, soft-float, position independent (-fPIE on
# the C side -> -fPIC for the relocatable Zig object). Unwind tables are
# disabled so we don't pull in libgcc's C++ unwinder.
ZIG_FLAGS = [
    'build-obj',
    '-target', 'thumb-freestanding-eabi',
    '-mcpu', 'cortex_m3',
    '-fPIC',
    '-fno-unwind-tables',
    '-O', 'ReleaseSmall',
]


def options(ctx):
    ctx.load('pebble_sdk')


def configure(ctx):
    ctx.load('pebble_sdk')
    ctx.env.ZIG = ZIG


def _zig_object(ctx, root_zig, out_name):
    """Compile `root_zig` (+ the shared pebble module) into a single ARM .o for
    the current platform, and return the resulting build Node."""
    pebble_mod = ctx.path.find_node('src/pebble.zig')
    root_node = ctx.path.find_node(root_zig)
    obj = ctx.path.get_bld().make_node('{}/{}'.format(ctx.env.BUILD_DIR, out_name))

    # Global flags MUST come before the -M module declarations, otherwise Zig
    # ignores -target and builds a host object.
    rule = ('${ZIG} ' + ' '.join(ZIG_FLAGS) +
            ' -femit-bin=${TGT}'
            ' --dep pebble -Mroot=${SRC[0]} -Mpebble=${SRC[1]}')
    ctx(rule=rule, source=[root_node, pebble_mod], target=obj)
    return obj


def build(ctx):
    ctx.load('pebble_sdk')

    build_worker = os.path.exists('worker_src')
    binaries = []

    cached_env = ctx.env
    for platform in ctx.env.TARGET_PLATFORMS:
        ctx.env = ctx.all_envs[platform]
        ctx.set_group(ctx.env.PLATFORM_NAME)

        app_obj = _zig_object(ctx, 'src/main.zig', 'zig-app.o')
        app_elf = '{}/pebble-app.elf'.format(ctx.env.BUILD_DIR)
        ctx.pbl_build(source=[app_obj], target=app_elf, bin_type='app')

        if build_worker:
            wkr_obj = _zig_object(ctx, 'worker_src/worker.zig', 'zig-worker.o')
            worker_elf = '{}/pebble-worker.elf'.format(ctx.env.BUILD_DIR)
            ctx.pbl_build(source=[wkr_obj], target=worker_elf, bin_type='worker')
            binaries.append({'platform': platform, 'app_elf': app_elf, 'worker_elf': worker_elf})
        else:
            binaries.append({'platform': platform, 'app_elf': app_elf})
    ctx.env = cached_env

    ctx.set_group('bundle')
    ctx.pbl_bundle(binaries=binaries, js=ctx.path.ant_glob(['src/pkjs/**/*.js']))