#!/bin/bash

# Path: Scripts/r.sh
set -e

BLUE='\033[1;34m'
YELLOW='\033[1;33m'
GREEN='\033[1;32m'
RED='\033[1;31m'
NC='\033[0m'

SCRIPT_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
source "$SCRIPT_DIR/lib/distro.sh"

PROG_DIR="$HOME/.programming"
R_ROOT="$PROG_DIR/r"
R_BIN_DIR="$R_ROOT/bin"
R_LIB_DIR="$R_ROOT/library"

mkdir -p "$R_BIN_DIR" "$R_LIB_DIR"

write_r_wrapper() {
    local target_name="$1"
    local command_body="$2"

    cat > "$R_BIN_DIR/$target_name" <<EOF
#!/bin/bash
set -e
export R_LIBS_USER="$R_LIB_DIR"
$command_body "\$@"
EOF

    chmod +x "$R_BIN_DIR/$target_name"
}

resolve_non_wrapper_command() {
    local target_name="$1"
    local original_path="$PATH"
    local filtered_parts=()
    local filtered_path=""
    local resolved_path=""
    local part

    IFS=':' read -r -a filtered_parts <<< "$PATH"

    local kept_parts=()
    for part in "${filtered_parts[@]}"; do
        if [ -n "$part" ] && [ "$part" != "$R_BIN_DIR" ]; then
            kept_parts+=("$part")
        fi
    done

    filtered_path=$(IFS=:; printf '%s' "${kept_parts[*]}")
    resolved_path=$(PATH="$filtered_path" command -v "$target_name" 2>/dev/null || true)

    PATH="$original_path"

    if [ -z "$resolved_path" ]; then
        echo -e "${RED}    ERROR:${NC} Could not resolve system command for $target_name outside $R_BIN_DIR"
        exit 1
    fi

    printf '%s\n' "$resolved_path"
}

echo -e "${BLUE}    LOG:${YELLOW} Detecting R installation strategy for $OS...${NC}"

if is_arch_family; then
    
    echo -e "${BLUE}    LOG:${YELLOW} Arch Linux detected. Using system R (Pacman)...${NC}"
    
    # Install R + Build Tools
    install_status=0
    install_packages r gcc-fortran curl tar || install_status=$?
    if [ "$install_status" -eq 42 ]; then
        exit 0
    elif [ "$install_status" -ne 0 ]; then
        exit "$install_status"
    fi
    
    echo -e "${GREEN}    SUCCESS:${NC} R installed via Pacman."
    
    R_BIN="R"
    SYSTEM_R_BIN="$(resolve_non_wrapper_command R)"
    SYSTEM_RSCRIPT_BIN="$(resolve_non_wrapper_command Rscript)"
    write_r_wrapper "R" "exec \"$SYSTEM_R_BIN\""
    write_r_wrapper "Rscript" "exec \"$SYSTEM_RSCRIPT_BIN\""

elif is_debian_family; then

    echo -e "${BLUE}    LOG:${YELLOW} Installing Debian build dependencies...${NC}"
    install_status=0
    install_packages gfortran curl tar ca-certificates || install_status=$?
    if [ "$install_status" -eq 42 ]; then
        exit 0
    elif [ "$install_status" -ne 0 ]; then
        exit "$install_status"
    fi

    if ! command -v rig >/dev/null 2>&1; then
        echo -e "${BLUE}    LOG:${YELLOW} Installing Rig for Debian/Ubuntu...${NC}"

        DEB_ARCH=$(dpkg --print-architecture)
        case "$DEB_ARCH" in
            amd64|arm64)
                ;;
            *)
                echo -e "${RED}    ERROR:${NC} Unsupported Debian architecture for Rig: $DEB_ARCH"
                exit 1
                ;;
        esac

        LATEST_REL_DATA=$(curl -fsSL https://api.github.com/repos/r-lib/rig/releases/latest)
        RIG_URL=$(echo "$LATEST_REL_DATA" | grep -o "https://[^\"]*r-rig_[^\"]*_${DEB_ARCH}\.deb" | head -n 1)

        if [ -z "$RIG_URL" ]; then
            echo -e "${RED}    ERROR:${NC} Could not find Rig .deb download URL for architecture: $DEB_ARCH"
            exit 1
        fi

        TEMP_DEB=$(mktemp --suffix=.deb)
        curl -fLsS "$RIG_URL" -o "$TEMP_DEB"
        sudo apt-get install -y "$TEMP_DEB"
        rm -f "$TEMP_DEB"
    fi

    TARGET_VER="release"
    if ! rig list | grep -q "release"; then
        echo -e "${BLUE}    LOG:${YELLOW} Installing R (${TARGET_VER})...${NC}"
        sudo rig add "$TARGET_VER" --without-cran-mirror
        sudo rig default "$TARGET_VER"
    fi
    
    R_BIN="R"
    SYSTEM_R_BIN="$(resolve_non_wrapper_command R)"
    SYSTEM_RSCRIPT_BIN="$(resolve_non_wrapper_command Rscript)"
    write_r_wrapper "R" "exec \"$SYSTEM_R_BIN\""
    write_r_wrapper "Rscript" "exec \"$SYSTEM_RSCRIPT_BIN\""

elif is_fedora_family; then

    echo -e "${BLUE}    LOG:${YELLOW} Fedora detected. Using system R...${NC}"
    install_status=0
    install_packages R-core R-core-devel gcc-gfortran curl tar || install_status=$?
    if [ "$install_status" -eq 42 ]; then
        exit 0
    elif [ "$install_status" -ne 0 ]; then
        exit "$install_status"
    fi

    R_BIN="R"
    SYSTEM_R_BIN="$(resolve_non_wrapper_command R)"
    SYSTEM_RSCRIPT_BIN="$(resolve_non_wrapper_command Rscript)"
    write_r_wrapper "R" "exec \"$SYSTEM_R_BIN\""
    write_r_wrapper "Rscript" "exec \"$SYSTEM_RSCRIPT_BIN\""

elif is_macos; then

    echo -e "${BLUE}    LOG:${YELLOW} macOS detected. Using Homebrew R...${NC}"
    install_status=0
    install_packages r || install_status=$?
    if [ "$install_status" -ne 0 ]; then
        exit "$install_status"
    fi

    R_BIN="R"
    SYSTEM_R_BIN="$(resolve_non_wrapper_command R)"
    SYSTEM_RSCRIPT_BIN="$(resolve_non_wrapper_command Rscript)"
    write_r_wrapper "R" "exec \"$SYSTEM_R_BIN\""
    write_r_wrapper "Rscript" "exec \"$SYSTEM_RSCRIPT_BIN\""

else
    echo -e "${RED}    ERROR:${NC} Unsupported OS: $OS"
    exit 1
fi

export R_LIBS_USER="$R_LIB_DIR"

if compgen -G "$R_LIB_DIR/00LOCK*" >/dev/null 2>&1; then
    echo -e "${RED}    ERROR:${NC} Detected existing R package lock(s) in $R_LIB_DIR"
    find "$R_LIB_DIR" -maxdepth 1 -type d -name '00LOCK*' -print | sed 's/^/      - /'
    echo -e "${YELLOW}    LOG:${NC} This usually means a previous R package install was interrupted."
    echo -e "${YELLOW}    LOG:${NC} Remove the stale lock directory/directories above, then rerun the command."
    exit 1
fi

echo -e "${BLUE}    LOG:${YELLOW} Installing 'renv' package in the user R library...${NC}"
echo -e "${BLUE}    LOG:${YELLOW} R user library: $R_LIB_DIR${NC}"
echo -e "${BLUE}    LOG:${YELLOW} R executable: $R_BIN_DIR/Rscript${NC}"

"$R_BIN_DIR/Rscript" --vanilla - <<'EOF'
user_lib <- path.expand(Sys.getenv("R_LIBS_USER", unset = "~/.programming/r/library"))
dir.create(user_lib, recursive = TRUE, showWarnings = FALSE)
.libPaths(c(user_lib, .libPaths()))

cat("R user library:", user_lib, "\n")
cat("R library paths:", paste(.libPaths(), collapse = " | "), "\n")

if (requireNamespace("renv", quietly = TRUE)) {
  cat("renv is already installed.\n")
  quit(save = "no", status = 0)
}

cat("Installing renv from CRAN...\n")
install.packages(
  "renv",
  lib = user_lib,
  repos = "https://cloud.r-project.org",
  quiet = FALSE
)

cat("Verifying renv installation...\n")
if (!requireNamespace("renv", quietly = TRUE)) {
  stop("renv install finished but the package is still unavailable.")
}

cat("renv installation verified.\n")
EOF

echo -e "${GREEN}    SUCCESS:${NC} R setup completed."