#!/usr/bin/env bash
# install.sh — install pi-extensions
#
# Symlinks each extension in extensions/ into ~/.pi/agent/extensions/ so pi
# loads them automatically on every session. Idempotent and non-destructive.
#
# Usage:
#   ./install.sh                          install all extensions
#   ./install.sh --only ssh-controlmaster install one extension
#   ./install.sh --only "ext1,ext2"       install a subset
#   ./install.sh --skip "ext1,ext2"       install all except these
#   ./install.sh --yes                    skip confirmation prompt
#   ./install.sh --uninstall              remove symlinks that point into this repo

set -euo pipefail

SCRIPT_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
EXTENSIONS_SRC="${SCRIPT_DIR}/extensions"
EXTENSIONS_DEST="${HOME}/.pi/agent/extensions"
PI_AGENT_DIR="${HOME}/.pi/agent"

# ── helpers ──────────────────────────────────────────
ok()   { printf ' \e[32m✓\e[0m  %s\n' "$*"; }
note() { printf '==> %s\n' "$*"; }
warn() { printf ' \e[33m!\e[0m  %s\n' "$*" >&2; }
err()  { printf ' \e[31m✗\e[0m  %s\n' "$*" >&2; }

confirm() {
    [[ "$ASSUME_YES" == "yes" ]] && return 0
    read -r -p "Proceed? [y/N] " ans
    [[ "$ans" =~ ^[Yy]$ ]]
}

link_into_repo() {
    local target
    [[ -L "$1" ]] || return 1
    target=$(readlink -f "$1" 2>/dev/null || true)
    [[ "$target" == "$SCRIPT_DIR"/* ]]
}

require_pi_installed() {
    if [[ ! -d "$PI_AGENT_DIR" ]]; then
        err "pi not detected at $PI_AGENT_DIR"
        printf '    Install pi first: https://github.com/mariozechner/pi-coding-agent\n'
        printf '    Re-run after `pi --help` (first run creates ~/.pi/agent/).\n'
        exit 4
    fi
    mkdir -p "$EXTENSIONS_DEST"
    ok "pi detected at $PI_AGENT_DIR"
}

# ── args ─────────────────────────────────────────────
ACTION="install"
ASSUME_YES="no"
ONLY=""     # comma-separated names to include  (empty = all)
SKIP=""     # comma-separated names to exclude  (empty = none)

while [[ $# -gt 0 ]]; do
    case "$1" in
        --uninstall)  ACTION="uninstall"; shift ;;
        -y|--yes)     ASSUME_YES="yes"; shift ;;
        --only)       ONLY="$2"; shift 2 ;;
        --only=*)     ONLY="${1#--only=}"; shift ;;
        --skip)       SKIP="$2"; shift 2 ;;
        --skip=*)     SKIP="${1#--skip=}"; shift ;;
        -h|--help)
            cat <<EOF
install.sh — install pi-extensions

Usage:
  ./install.sh                          install all extensions
  ./install.sh --only ssh-controlmaster install one extension
  ./install.sh --only "ext1,ext2"       install a subset
  ./install.sh --skip "ext1,ext2"       install all except these
  ./install.sh --yes                    skip confirmation prompt
  ./install.sh --uninstall              remove symlinks that point into this repo

--only and --skip accept comma-separated extension names (without .ts suffix).
--only takes precedence over --skip if both are given.

Each .ts file in extensions/ is symlinked into ~/.pi/agent/extensions/.
Existing files already symlinked into this repo are left alone.
Existing real files or foreign symlinks are backed up with a timestamp.
EOF
            exit 0 ;;
        *) echo "Unknown flag: $1" >&2; exit 2 ;;
    esac
done

# ── build install set ─────────────────────────────────
# INSTALL_SET: space-delimited bare names (no .ts suffix). Bash 3 compatible.
INSTALL_SET=""

in_install_set() { [[ " $INSTALL_SET " == *" $1 "* ]]; }

build_install_set() {
    local n f bare entry new
    if [[ -n "$ONLY" ]]; then
        # Explicit allowlist — only install what's named
        IFS=',' read -ra names <<< "$ONLY"
        for n in "${names[@]}"; do
            INSTALL_SET="${INSTALL_SET:+$INSTALL_SET }${n%.ts}"
        done
    else
        # Start with everything present on disk, then remove --skip entries
        for f in "${EXTENSIONS_SRC}"/*.ts; do
            [[ -e "$f" ]] && INSTALL_SET="${INSTALL_SET:+$INSTALL_SET }$(basename "$f" .ts)"
        done
        if [[ -n "$SKIP" ]]; then
            IFS=',' read -ra names <<< "$SKIP"
            for n in "${names[@]}"; do
                bare="${n%.ts}"
                new=""
                for entry in $INSTALL_SET; do
                    [[ "$entry" == "$bare" ]] || new="${new:+$new }$entry"
                done
                INSTALL_SET="$new"
            done
        fi
    fi
}

# ── install ──────────────────────────────────────────
do_install() {
    echo
    echo "pi-extensions installer"
    echo "Repository: $SCRIPT_DIR"
    echo

    require_pi_installed
    build_install_set

    if [[ -z "$INSTALL_SET" ]]; then
        warn "No extensions selected — nothing to install."
        exit 0
    fi

    echo "==> Extensions to symlink into ${EXTENSIONS_DEST}/:"
    for n in $INSTALL_SET; do
        printf '       %s.ts\n' "$n"
    done
    echo
    confirm || { echo "Aborted."; exit 0; }
    echo

    for src in "${EXTENSIONS_SRC}"/*.ts; do
        [[ -e "$src" ]] || continue
        local name
        name="$(basename "$src")"
        local bare="${name%.ts}"
        in_install_set "$bare" || continue

        local dest="${EXTENSIONS_DEST}/${name}"
        local disabled="${dest}.off"

        note "Linking ${name}"

        # Respect a prior /ext disable: if <name>.ts.off exists and points
        # into this repo, leave it alone. ext-toggle will flip it back.
        if [[ -L "$disabled" ]] && link_into_repo "$disabled"; then
            ok "${name} kept disabled (${name}.off present)"
            continue
        fi

        if [[ -e "$dest" || -L "$dest" ]]; then
            if link_into_repo "$dest"; then
                ok "${name} already linked"
                continue
            fi
            local backup="${dest}.bak.$(date +%Y%m%d-%H%M%S)"
            mv "$dest" "$backup"
            warn "Existing ${dest} backed up to ${backup}"
        fi

        ln -s "$src" "$dest"
        ok "Linked ${name} → ${src}"
    done

    echo
    ok "Done. Reload pi with /reload or restart to pick up new extensions."
}

# ── uninstall ────────────────────────────────────────
do_uninstall() {
    echo
    echo "pi-extensions uninstaller"
    echo "Repository: $SCRIPT_DIR"
    echo
    confirm || { echo "Aborted."; exit 0; }
    echo

    local removed=0
    # Match both active (.ts) and disabled (.ts.off) symlinks — the ext-toggle
    # extension can rename a link to .ts.off to disable it, and uninstall
    # should still clean those up.
    for pattern in "*.ts" "*.ts.off"; do
        for dest in "${EXTENSIONS_DEST}"/$pattern; do
            [[ -e "$dest" || -L "$dest" ]] || continue
            if link_into_repo "$dest"; then
                rm "$dest"
                ok "Removed $(basename "$dest")"
                (( removed++ )) || true
            fi
        done
    done

    if [[ $removed -eq 0 ]]; then
        ok "No symlinks pointing into this repo found — nothing removed."
    else
        echo
        ok "Done. Removed ${removed} symlink(s)."
    fi
}

case "$ACTION" in
    install)   do_install ;;
    uninstall) do_uninstall ;;
esac