#!/usr/bin/env bash
#
# Set up shared agent state for agent-container.
#
# Moves agent state (Claude Code, Pi, OpenCode) from the real $HOME into the
# container home and symlinks it back, so the containerized tools (claude, pi,
# opencode) and the local variants (claude-local, pi-local, opencode-local)
# share logins, settings, and history. See README.md, section "Sharing agent
# state between host and container via symlinks".
#
# Safe to re-run: already shared items are detected and left alone.

set -euo pipefail

XDG_DATA_HOME="${XDG_DATA_HOME:-$HOME/.local/share}"
CONTAINER_HOME="$XDG_DATA_HOME/agent-container/container-home"

# State directories to share. Created in the container home (and linked into
# $HOME) even if they don't exist yet, so both sides share from the start.
DIRS=(
    .claude
    .pi
    .agents
    .config/opencode
    .local/share/opencode
)

# Single files to share. Only linked when they exist on one side, tools create
# them on first use.
FILES=(
    .claude.json
)

info() { printf '  %s\n' "$*"; }
warn() { printf '  warning: %s\n' "$*" >&2; }

# Print the action taken for an item, shared by both helpers below.
_report() {
    local action="$1" item="$2"
    case "$action" in
        moved)   info "moved   $item into the container home, symlinked from \$HOME" ;;
        linked)  info "linked  $item (container home already had it)" ;;
        created) info "created $item in the container home, symlinked from \$HOME" ;;
        ok)      info "ok      $item (already shared)" ;;
        skip)    info "skip    $item (does not exist yet, the tool will create it)" ;;
    esac
}

share_item() {
    local item="$1" must_exist="$2"
    local host="$HOME/$item" target="$CONTAINER_HOME/$item"

    if [ -L "$host" ]; then
        case "$(readlink -f "$host")" in
            "$CONTAINER_HOME"/*)
                _report ok "$item"
                return
                ;;
            *)
                warn "$item is a symlink to $(readlink "$host"), not touching it"
                return
                ;;
        esac
    fi

    if [ -e "$host" ] && [ -e "$target" ]; then
        warn "$item exists in both \$HOME and the container home"
        warn "reconcile the two copies manually, then re-run this script"
        return
    fi

    if [ ! -e "$host" ] && [ ! -e "$target" ]; then
        if [ "$must_exist" = "yes" ]; then
            _report skip "$item"
            return
        fi
        mkdir -p "$target"
        _report created "$item"
    elif [ -e "$host" ]; then
        mkdir -p "$(dirname "$target")"
        mv "$host" "$target"
        _report moved "$item"
    else
        _report linked "$item"
    fi

    mkdir -p "$(dirname "$host")"
    ln -s "$target" "$host"
}

main() {
    printf 'Sharing agent state via %s\n\n' "$CONTAINER_HOME"

    local item
    for item in "${DIRS[@]}";  do share_item "$item" no;  done
    for item in "${FILES[@]}"; do share_item "$item" yes; done

    if [ -f "$HOME/.gitconfig" ] && [ ! -e "$CONTAINER_HOME/.gitconfig" ]; then
        printf '\n'
        info "Tip: share your git config too (see README):"
        info "  ln $HOME/.gitconfig $CONTAINER_HOME/.gitconfig"
    fi
}

main "$@"