#!/usr/bin/env bash
#
# Verify prerequisites for every recipe. For each missing item, prints the
# EXACT command to install it on the detected platform. Exits non-zero if
# any hard requirement is missing; warns but continues for PATH hygiene
# and the web-browser check (headless systems can still use login-headless).

set -euo pipefail

here="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd -P)"
# shellcheck disable=SC1091
. "$here/common.sh"

# ---------------------------------------------------------------------------
# Platform detection
# ---------------------------------------------------------------------------
uname_s="$(uname -s 2>/dev/null || echo unknown)"
pm=""   # one of: apt dnf pacman zypper brew ""
case "$uname_s" in
    Linux)
        if [ -r /etc/os-release ]; then
            # shellcheck disable=SC1091
            . /etc/os-release
            id_all=" ${ID:-} ${ID_LIKE:-} "
            case "$id_all" in
                *' debian '*|*' ubuntu '*)              pm=apt ;;
                *' fedora '*|*' rhel '*|*' centos '*)   pm=dnf ;;
                *' arch '*)                             pm=pacman ;;
                *' opensuse '*|*' suse '*)              pm=zypper ;;
            esac
        fi
        if [ -z "$pm" ]; then
            for candidate in apt-get dnf pacman zypper; do
                if command -v "$candidate" >/dev/null 2>&1; then
                    case "$candidate" in
                        apt-get) pm=apt ;;
                        dnf)     pm=dnf ;;
                        pacman)  pm=pacman ;;
                        zypper)  pm=zypper ;;
                    esac
                    break
                fi
            done
        fi
        ;;
    Darwin)
        pm=brew
        ;;
esac

# ---------------------------------------------------------------------------
# Render a package-install command for the current platform.
#   pkg_cmd <apt> <dnf> <pacman> <brew> <upstream-url>
# ---------------------------------------------------------------------------
pkg_cmd() {
    local apt_pkg="$1" dnf_pkg="$2" pac_pkg="$3" brew_pkg="$4" url="$5"
    case "$pm" in
        apt)    echo "sudo apt-get update && sudo apt-get install -y $apt_pkg" ;;
        dnf)    echo "sudo dnf install -y $dnf_pkg" ;;
        pacman) echo "sudo pacman -S --noconfirm $pac_pkg" ;;
        zypper) echo "sudo zypper install -y $dnf_pkg" ;;
        brew)   echo "brew install $brew_pkg" ;;
        *)      echo "# install manually from: $url" ;;
    esac
}

# ---------------------------------------------------------------------------
# Accumulators
# ---------------------------------------------------------------------------
missing=0
fix_commands=()

record_miss() {
    local name="$1" detail="$2" fix="$3"
    printf '  %s %-12s -> %s\n' "$(_fc_tag "$_FC_RED" miss)" "$name" "$detail"
    printf '         fix: %s\n' "$fix"
    fix_commands+=("$fix")
    missing=$((missing + 1))
}

check_cmd() {
    local cmd="$1" fix="$2"
    if command -v "$cmd" >/dev/null 2>&1; then
        printf '  %s %-12s -> %s\n' "$(_fc_tag "$_FC_GREEN" ok)" "$cmd" "$(command -v "$cmd")"
    else
        record_miss "$cmd" "not found on PATH" "$fix"
    fi
}

info 'checking prerequisites...'

# ---------------------------------------------------------------------------
# Required tools
# ---------------------------------------------------------------------------
check_cmd git     "$(pkg_cmd git       git       git       git       https://git-scm.com/)"
check_cmd bash    "$(pkg_cmd bash      bash      bash      bash      https://www.gnu.org/software/bash/)"
check_cmd curl    "$(pkg_cmd curl      curl      curl      curl      https://curl.se/)"
check_cmd install "$(pkg_cmd coreutils coreutils coreutils coreutils https://www.gnu.org/software/coreutils/)"
check_cmd python3 "$(pkg_cmd python3   python3   python    python3   https://www.python.org/)"

# just and uv do not ship in most package managers, so prefer the upstream
# installers (no sudo, land binaries in ~/.local/bin / ~/.cargo/bin).
check_cmd just 'curl --proto "=https" --tlsv1.2 -LsSf https://just.systems/install.sh | bash -s -- --to "$HOME/.local/bin"'
check_cmd uv   'curl -LsSf https://astral.sh/uv/install.sh | sh'

# ---------------------------------------------------------------------------
# Web browser (warning only: headless is supported via login-headless)
# ---------------------------------------------------------------------------
if command -v xdg-open >/dev/null 2>&1 || command -v open >/dev/null 2>&1; then
    printf '  %s %-12s -> (detected)\n' "$(_fc_tag "$_FC_GREEN" ok)" 'web browser'
else
    printf '  %s %-12s -> no xdg-open/open on PATH.\n' "$(_fc_tag "$_FC_YELLOW" warn)" 'web browser'
    printf '         headless mode: just login-headless\n'
    case "$pm" in
        apt)    printf '         otherwise install:  sudo apt-get install -y xdg-utils\n' ;;
        dnf)    printf '         otherwise install:  sudo dnf install -y xdg-utils\n' ;;
        pacman) printf '         otherwise install:  sudo pacman -S --noconfirm xdg-utils\n' ;;
    esac
fi

# ---------------------------------------------------------------------------
# Python 3.11+ : accepted via system python3 OR uv-managed interpreter
# ---------------------------------------------------------------------------
py_ok=0
py_via=""
if command -v python3 >/dev/null 2>&1; then
    if python3 - <<'PY' >/dev/null 2>&1
import sys
sys.exit(0 if sys.version_info >= (3, 11) else 1)
PY
    then
        py_ok=1
        py_via="$(python3 -V 2>&1)"
    fi
fi
if [ "$py_ok" -eq 0 ] && command -v uv >/dev/null 2>&1; then
    if uv_py_path="$(uv python find '>=3.11' 2>/dev/null)" && [ -n "$uv_py_path" ]; then
        py_ok=1
        py_via="$uv_py_path (via uv)"
    fi
fi

if [ "$py_ok" -eq 1 ]; then
    printf '  %s %-12s -> %s\n' "$(_fc_tag "$_FC_GREEN" ok)" 'python>=3.11' "$py_via"
else
    detail='python3 missing'
    if command -v python3 >/dev/null 2>&1; then
        detail="python3 is $(python3 -V 2>&1 | awk '{print $2}'); need 3.11+"
    fi
    # Primary fix: uv-managed Python. Works on every platform, no sudo, and
    # the orchestrator (a uv project) will resolve it automatically via
    # `uv run` / `uv sync`.
    py_fix='uv python install 3.11'
    # Per-distro alternative (commented so users can copy one or the other):
    case "$pm" in
        apt)
            py_alt='sudo add-apt-repository -y ppa:deadsnakes/ppa && sudo apt-get update && sudo apt-get install -y python3.11 python3.11-venv'
            ;;
        dnf)
            py_alt='sudo dnf install -y python3.11'
            ;;
        pacman)
            py_alt='sudo pacman -S --noconfirm python'
            ;;
        zypper)
            py_alt='sudo zypper install -y python311'
            ;;
        brew)
            py_alt='brew install python@3.11'
            ;;
        *)
            py_alt=''
            ;;
    esac
    printf '  %s %-12s -> %s\n' "$(_fc_tag "$_FC_RED" miss)" 'python>=3.11' "$detail"
    printf '         fix: %s\n' "$py_fix"
    if [ -n "$py_alt" ]; then
        printf '         alt: %s\n' "$py_alt"
    fi
    fix_commands+=("$py_fix")
    missing=$((missing + 1))
fi

# ---------------------------------------------------------------------------
# PATH hygiene: warning, not a hard miss.
# ---------------------------------------------------------------------------
case ":$PATH:" in
    *":$LOCAL_BIN:"*)
        printf '  %s %-12s -> %s is on PATH\n' "$(_fc_tag "$_FC_GREEN" ok)" 'PATH' "$LOCAL_BIN"
        ;;
    *)
        rc='~/.bashrc'
        [ -n "${ZSH_VERSION:-}" ] && rc='~/.zshrc'
        printf '  %s %-12s -> %s is NOT on PATH.\n' "$(_fc_tag "$_FC_YELLOW" warn)" 'PATH' "$LOCAL_BIN"
        # shellcheck disable=SC2016
        printf "         fix: echo 'export PATH=\"%s:\$PATH\"' >> %s && exec \$SHELL -l\n" "$LOCAL_BIN" "$rc"
        ;;
esac

# ---------------------------------------------------------------------------
# Summary
# ---------------------------------------------------------------------------
if [ "$missing" -gt 0 ]; then
    printf '\n'
    warn "$missing prerequisite(s) missing. Run the following to fix them:"
    printf '\n'
    # De-duplicate while preserving order.
    seen=''
    for c in "${fix_commands[@]}"; do
        case "$seen" in
            *"<<$c>>"*) continue ;;
        esac
        seen="$seen<<$c>>"
        printf '    %s\n' "$c"
    done
    printf '\n'
    warn 're-run: just doctor'
    exit 1
fi

info 'all prerequisites present'