#!/usr/bin/env bash
# Builds SQLite from its amalgamation into a prefix: <prefix>/lib/libsqlite3.a,
# <prefix>/include/sqlite3.h and a pkg-config file, which the sqlite3 opam
# package then finds. The source tarball is downloaded once into .cache/src,
# checked against sqlite.org's SHA3-256, and kept by make clean-deps.
#   tools/sqlite.sh fetch          (on the host)
#   tools/sqlite.sh build <prefix> (with the target's C compiler)
set -euo pipefail
app=$(cd "$(dirname "$0")/.." && pwd)
version=3540100
sha3=b6ced585c750916b1052667239a12c25a7ff34e7f06e1e6e01ecb0427657d9c4
tarball=$app/.cache/src/sqlite-autoconf-$version.tar.gz

case $1 in
fetch)
  [ -f "$tarball" ] && exit 0
  mkdir -p "$(dirname "$tarball")"
  curl -sSfo "$tarball.part" "https://sqlite.org/2026/sqlite-autoconf-$version.tar.gz"
  got=$(python3 -c 'import hashlib,sys; print(hashlib.sha3_256(open(sys.argv[1],"rb").read()).hexdigest())' "$tarball.part")
  [ "$got" = "$sha3" ] || { echo "sqlite: SHA3-256 mismatch: $got" >&2; rm -f "$tarball.part"; exit 1; }
  mv "$tarball.part" "$tarball"
  ;;
build)
  prefix=$2
  [ -f "$prefix/lib/libsqlite3.a" ] && exit 0
  rm -rf "$prefix" && mkdir -p "$prefix/build" "$prefix/lib/pkgconfig" "$prefix/include"
  tar xzf "$tarball" -C "$prefix/build" --strip-components=1 \
    "sqlite-autoconf-$version/sqlite3.c" "sqlite-autoconf-$version/sqlite3.h" "sqlite-autoconf-$version/sqlite3ext.h"
  # -fPIC: the x86 build also links it into the OCaml stubs' shared library.
  cc -c -O2 -fPIC -DSQLITE_THREADSAFE=1 -DSQLITE_DQS=0 -DSQLITE_DEFAULT_MEMSTATUS=0 \
    -DSQLITE_OMIT_DEPRECATED -DSQLITE_OMIT_SHARED_CACHE \
    -o "$prefix/build/sqlite3.o" "$prefix/build/sqlite3.c"
  ar rcs "$prefix/lib/libsqlite3.a" "$prefix/build/sqlite3.o"
  cp "$prefix/build/sqlite3.h" "$prefix/build/sqlite3ext.h" "$prefix/include/"
  rm -rf "$prefix/build"
  cat > "$prefix/lib/pkgconfig/sqlite3.pc" <<EOS
Name: SQLite
Description: SQL database engine, built by tools/sqlite.sh
Version: ${version:0:1}.${version:1:2}.${version:4:1}
Cflags: -I$prefix/include
Libs: -L$prefix/lib -lsqlite3
Libs.private: -lm -lpthread
EOS
  ;;
esac