#!/usr/bin/env bash
set -e

# Set default variables
if [ -z "$SECP_VENDOR_GIT_ROOT" ]; then
    SECP_VENDOR_GIT_ROOT="$(git rev-parse --show-toplevel)"
else
    SECP_VENDOR_GIT_ROOT="$(realpath "$SECP_VENDOR_GIT_ROOT")"
fi
SECP_SYS="$SECP_VENDOR_GIT_ROOT"/secp256k1-sys
DEFAULT_VERSION_CODE=$(grep version "$SECP_SYS/Cargo.toml" | sed 's/\./_/g' | sed 's/.*"\(.*\)".*/\1/')
DEFAULT_DEPEND_DIR="$SECP_SYS/depend"
DEFAULT_SECP_REPO=https://github.com/bitcoin-core/secp256k1.git

: "${SECP_VENDOR_VERSION_CODE:=$DEFAULT_VERSION_CODE}"
: "${SECP_VENDOR_DEPEND_DIR:=$DEFAULT_DEPEND_DIR}"
: "${SECP_VENDOR_SECP_REPO:=$DEFAULT_SECP_REPO}"
# CP_NOT_CLONE lets us just copy a directory rather than git cloning.
# This is usually a bad idea, since it will bring in build artifacts or any other
# junk from the source directory, but may be useful during development or CI.
: "${SECP_VENDOR_CP_NOT_CLONE:=no}"

echo "Using version code $SECP_VENDOR_VERSION_CODE. Set SECP_VENDOR_VERSION_CODE to override."
echo "Using depend directory $SECP_VENDOR_DEPEND_DIR. Set SECP_VENDOR_DEPEND_DIR to override."
echo "Using secp repository $SECP_VENDOR_SECP_REPO. Set SECP_VENDOR_SECP_REPO to override."

# Parse command-line options
SECP_REV=""
FORCE=no
while (( "$#" )); do
    case "$1" in
    -f)
        FORCE=yes
        ;;
    *)
        if [ -z "$SECP_REV" ]; then
            echo "Using secp256k1 revision $SECP_REV."
            SECP_REV="$1"
        else
            echo "WARNING: ignoring unknown command-line argument $1"
        fi
        ;;
    esac
    shift
done

if [ -z "$SECP_REV" ]; then
    echo "WARNING: No secp256k1 revision specified. Will use whatever we find at the git repo."
fi
echo

# Check if we will do anything destructive.

if [ "$FORCE" == "no" ]; then
    if ! git diff --quiet -- "*.rs"; then
        echo "ERROR: There appear to be modified source files. Check these in or pass -f (some source files will be modified to have symbols renamed)."
        exit 2
    fi
    if ! git diff --quiet -- "$SECP_VENDOR_DEPEND_DIR"; then
        echo "ERROR: The depend directory appears to be modified. Check it in or pass -f (this directory will be deleted)."
        exit 2
    fi
fi

DIR=./secp256k1

pushd "$SECP_VENDOR_DEPEND_DIR" > /dev/null
rm -rf "$DIR" || true

# Clone the repo. As a special case, if the repo is a local path and we have
# not specified a revision, just copy the directory rather than using 'git clone'.
# This lets us use non-git repos or dirty source trees as secp sources.
if [ "$SECP_VENDOR_CP_NOT_CLONE" == "yes" ]; then
    cp -r "$SECP_VENDOR_SECP_REPO" "$DIR"
    chmod -R +w "$DIR" # cp preserves write perms, which if missing will cause patch to fail
else
    git clone "$SECP_VENDOR_SECP_REPO" "$DIR"
fi

# Check out specified revision
pushd "$DIR" > /dev/null
if [ -n "$SECP_REV" ]; then
    git checkout "$SECP_REV"
fi
SOURCE_REV=$(git rev-parse HEAD || echo "[unknown revision from $SECP_VENDOR_SECP_REPO]")
rm -rf .git/ || true
popd

# Record revision
echo "# This file was automatically created by $(basename "$0")" > ./secp256k1-HEAD-revision.txt
echo "$SOURCE_REV" >> ./secp256k1-HEAD-revision.txt

# Patch source files

# To support compiling for WASM, we need to remove all methods that use malloc.
# To compensate, the secp_context_create and _destroy methods are redefined in Rust.
patch "$DIR/include/secp256k1.h" "./secp256k1.h.patch"
patch "$DIR/src/secp256k1.c" "./secp256k1.c.patch"
patch "$DIR/src/scratch_impl.h" "./scratch_impl.h.patch"
patch "$DIR/src/util.h" "./util.h.patch"

# Fix a linking error while cross-compiling to windowns with mingw
patch "$DIR/contrib/lax_der_parsing.c" "./lax_der_parsing.c.patch"

# Prefix all methods with rustsecp and a version prefix
find "$DIR" \
    -not -path '*/\.*' \
    -not -name "CHANGELOG.md" \
    -type f \
    -print0 | xargs -0 sed -i "/^#include/! s/secp256k1_/rustsecp256k1_v${SECP_VENDOR_VERSION_CODE}_/g"
# special rule for a method that is not prefixed in libsecp
find "$DIR" \
    -not -path '*/\.*' \
    -type f \
    -print0 | xargs -0 sed -i "/^#include/! s/ecdsa_signature_parse_der_lax/rustsecp256k1_v${SECP_VENDOR_VERSION_CODE}_ecdsa_signature_parse_der_lax/g"

cd "$SECP_SYS"
# Update the `links = ` in the manifest file.
sed -i -r "s/^links = \".*\"$/links = \"rustsecp256k1_v${SECP_VENDOR_VERSION_CODE}\"/" Cargo.toml
# Update the extern references in the Rust FFI source files.
find "./src/" \
    -name "*.rs" \
    -type f \
    -print0 | xargs -0 sed -i -r "s/rustsecp256k1_v[0-9]+_[0-9]+_[0-9]+_(.*)([\"\(])/rustsecp256k1_v${SECP_VENDOR_VERSION_CODE}_\1\2/g"

popd > /dev/null