# slosh in a browser tab.
#
# Bellard's TinyEMU compiled to wasm boots a riscv64 Linux; we hand it a root
# filesystem with a cross-compiled slosh in it. `make` builds the whole thing
# into build/site, `make serve` puts it on a port.
#
# Run this from web/demo (or `make -C web/demo`), not from the
# repository root: it is a separate build with a separate target triple and it
# deliberately shares nothing with the top-level one but the source files.

ROOT     := ../..
ZIG      ?= $(HOME)/zig-0.16.0/zig
CC       := $(ZIG) cc
TARGET   := riscv64-linux-musl

VT       := $(ROOT)/vendor/libghostty-vt
VT_OUT   := build/vt
VT_LIB   := $(VT_OUT)/lib/libghostty-vt.a
VT_INC   := $(VT_OUT)/include

SRC      := $(wildcard $(ROOT)/src/*.c)
OBJ      := $(patsubst $(ROOT)/src/%.c,build/obj/%.o,$(SRC))
DEPS     := $(OBJ:.o=.d)
GUEST    := build/slosh-riscv64

# -Os, no -g: every byte of this binary is pulled through a virtio block device
# by somebody's browser, 256 KiB at a time.
CFLAGS   := -target $(TARGET) -std=c23 -Os -Wall -Wextra -Wno-unused-parameter \
            -MMD -MP -I$(VT_INC) -I$(ROOT)/include -Ibuild
# The same derivation as every other artifact (contrib/version: the tag is
# the single source of truth), so the demo cannot fall behind a release the
# way a hand-written number here once did. +webdemo, because this binary is
# the riscv64 guest build and should say so when someone asks it.
VERSION  := $(shell cd $(ROOT) && contrib/version)

SITE     := build/site
IMAGE    := build/rootfs.bin
IMAGE_MB ?= 48
PORT     ?= 8000

# What the browser downloads, beyond our own page. The emulator comes from
# emulator/dist -- ours, built from Bellard's source -- not from vendor/:
# his prebuilt blob wedges on disks larger than 16 MiB (see emulator/).
VENDOR_SITE := bbl64.bin kernel-riscv64.bin xterm.js xterm.css
EMU_SITE    := emulator/dist/riscvemu64-wasm.js emulator/dist/riscvemu64-wasm.wasm
WEB_SITE    := index.html demo.js demo.css slosh.cfg

V ?= 0
ifeq ($(V),0)
  Q   := @
  say  = @printf '  %-5s %s\n' '$(1)' '$(2)'
else
  Q   :=
  say  = @:
endif

.PHONY: all vendor guest rootfs site serve check clean distclean help
.DEFAULT_GOAL := help

help: ## show this
	@grep -hE '^[a-z-]+:.*##' $(MAKEFILE_LIST) | sed 's/:.*##/\t/' | expand -t14
	@printf '\n%-13s %s\n' 'PORT=8080' 'which port `make serve` uses'
	@printf '%-13s %s\n' 'IMAGE_MB=64' 'how big the guest filesystem is'

all: site ## build everything into build/site

# ── the third-party half ────────────────────────────────────────────────────

vendor: vendor/.stamp ## download the emulator, kernel, base image and xterm.js

vendor/.stamp: fetch-vendor
	$(Q)./fetch-vendor
	@touch $@

# ── slosh, for a machine nobody here owns ─────────────────────────────────
#
# -Dsimd=false is not a size choice: Google Highway, which libghostty-vt uses
# for SIMD, does not compile for rv64gc -- it emits RVV intrinsics for a vector
# extension this target does not have. The scalar paths are the same code
# without the hand-vectorised fast path, which for a demo VM is free.
# -Dversion-string, as at the top level: the vendored tree has no .git, so
# upstream's version detection runs `git describe` in *our* repository -- and
# on a tag checkout (exactly where web/publish builds a release site) it
# finds a slosh tag, which upstream treats as a fatal mismatch. The manifest
# prerequisite is the top level's too: a vendor bump must rebuild this lib,
# or the demo compiles new code against the old headers. Both stayed hidden
# behind a stale build/vt until v0.1.7 cleared it.
VT_VERSION := $(shell sed -n 's/^[[:space:]]*\.version = "\([^"]*\)".*/\1/p' $(VT)/build.zig.zon | head -1)

$(VT_LIB): $(VT).vendor.json
	$(call say,[ZIG],libghostty-vt $(TARGET))
	$(Q)cd $(VT) && PATH="$(dir $(ZIG)):$$PATH" zig build \
	    -Demit-lib-vt -Dsimd=false -Doptimize=ReleaseFast -Dtarget=$(TARGET) \
	    -Dversion-string=$(VT_VERSION) \
	    --prefix $(abspath $(VT_OUT)) --cache-dir $(abspath build/vt-cache)

# FORCE, as at the top level: rewritten only when the value actually changes,
# so a new commit rebuilds and `make` twice in a row does not.
.PHONY: FORCE
build/version.h: FORCE | build
	@printf '/* generated by web/demo/Makefile */\n#define SLOSH_VERSION "%s+webdemo"\n' \
	  '$(VERSION)' > $@.tmp
	@cmp -s $@.tmp $@ || mv $@.tmp $@
	@rm -f $@.tmp

build build/obj:
	@mkdir -p build/obj

# The logo, exactly as the top-level Makefile bakes it: logo.txt is the
# source of truth and the splash includes this.
build/logo.h: $(ROOT)/logo.txt | build
	$(call say,[GEN],$@)
	$(Q){ printf '/* generated from logo.txt; edit that, not this */\n'; \
	  printf 'static const char *const LOGO[] = {\n'; \
	  sed -e 's/\\\\/\\\\\\\\/g' -e 's/"/\\\\"/g' -e 's/^/    "/' -e 's/$$/",/' $(ROOT)/logo.txt; \
	  printf '};\n'; } > $@

# The embedded terminfo entry, exactly as the top-level Makefile bakes it:
# pty.c includes it, and this Makefile compiles pty.c with its own rules.
build/terminfo.h: $(ROOT)/contrib/terminfo/xterm-ghostty.terminfo | build
	$(call say,[GEN],$@)
	$(Q){ printf '/* generated from contrib/terminfo/xterm-ghostty.terminfo */\n'; \
	  printf 'static const unsigned char TERMINFO_GHOSTTY[] = {\n'; \
	  od -An -v -tx1 $< | sed -e 's/ \([0-9a-f][0-9a-f]\)/0x\1,/g'; \
	  printf '};\n'; } > $@

build/obj/%.o: $(ROOT)/src/%.c build/version.h build/logo.h build/terminfo.h $(VT_LIB) | build/obj
	$(call say,[CC],$(notdir $<))
	$(Q)$(CC) $(CFLAGS) -c $< -o $@

# stb_image is third-party and does not build clean under our warnings.
build/obj/png.o: $(ROOT)/src/png.c build/version.h $(VT_LIB) | build/obj
	$(call say,[CC],$(notdir $<))
	$(Q)$(CC) $(CFLAGS) -I$(VT)/src/stb -Wno-unused-function -c $< -o $@

# Static, because the guest has glibc 2.24 and we built against musl. It also
# means the binary is the only thing that has to land in the image.
$(GUEST): $(OBJ) $(VT_LIB)
	$(call say,[LD],$@)
	$(Q)$(CC) -target $(TARGET) -Os $(OBJ) $(VT_LIB) -o $@ -s

guest: $(GUEST) ## cross-compile slosh for riscv64

# ── the guest filesystem ────────────────────────────────────────────────────
#
# The kernel we use has no initramfs support (CONFIG_BLK_DEV_INITRD is off: it
# ignores an initrd and panics for want of a root), so the root filesystem is an
# ext2 image on a virtio disk, split into 256 KiB blocks that the emulator
# fetches over HTTP as the guest touches them. A visitor downloads the parts of
# the image they use, not all of it.
rootfs: $(IMAGE) ## build and split the guest filesystem

# find -L: overlay contains a symlink (the theme, pointing into contrib/themes)
# and -type f without -L skips symlinks -- editing the theme would not rebuild
# the image. With -L the prereq is the symlink path, and make stats through it,
# so the target's mtime is the one compared.
$(IMAGE): $(GUEST) build-rootfs vendor/.stamp $(shell find -L overlay -type f 2>/dev/null)
	$(Q)./build-rootfs --base vendor/alpine-minirootfs-riscv64.tar.gz --slosh $(GUEST) \
	    --apks vendor/apks --overlay overlay --out $@ --split $(SITE)/rootfs --size $(IMAGE_MB)M

# Everything except the page can be checked without a browser: same emulator,
# same kernel, same image, driven over a pty. `make check` before you open
# devtools, always.
check: $(IMAGE) ## boot the image in a native emulator and check slosh runs
	$(Q)./boot-check

# ── the page ────────────────────────────────────────────────────────────────

site: $(IMAGE) ## assemble build/site
	@mkdir -p $(SITE)
	$(Q)cp $(addprefix web/,$(WEB_SITE)) $(SITE)/
	$(Q)cp $(addprefix vendor/,$(VENDOR_SITE)) $(SITE)/
	$(Q)cp $(EMU_SITE) $(SITE)/
	$(Q)cp vendor/TINYEMU-MIT-LICENSE.txt $(SITE)/
	$(Q)for f in kernel-riscv64.bin bbl64.bin riscvemu64-wasm.js riscvemu64-wasm.wasm \
	             xterm.js xterm.css demo.js demo.css; do \
	    gzip -9 -n -c $(SITE)/$$f > $(SITE)/$$f.gz; \
	done
	@printf '  site  %s (%s; %s gzipped)\n' "$(SITE)" \
	  "$$(du -sh $(SITE) | cut -f1)" \
	  "$$(du -shc $(SITE)/*.gz $(SITE)/rootfs/*.gz 2>/dev/null | tail -1 | cut -f1)"

serve: site ## serve build/site on http://localhost:$(PORT)
	./serve --dir $(SITE) --port $(PORT)

clean: ## remove build/ (keeps the downloads)
	rm -rf build

distclean: clean ## also remove vendor/
	rm -rf vendor

-include $(DEPS)