#!/usr/bin/env bash
# Symlink centralized skills/commands/hooks/context into each agent's config dir.
# For non-Nix machines (NixOS boxes use nix/home.nix instead).
# Idempotent. Backs up any pre-existing real dir once to <name>.bak.
set -euo pipefail

REPO="$(cd "$(dirname "$0")/.." && pwd)"

# targets: agent config skill roots. Claude Code reads ~/.claude/skills,
# Pi reads ~/.agents/skills, opencode auto-loads both dirs, and Codex reads
# $CODEX_HOME/skills and nothing else -- ~/.agents/skills is invisible to it,
# which is how review sessions ended up reporting an unavailable review-pr
# skill. All four consume the same SKILL.md dirs.
CLAUDE_SKILLS="$HOME/.claude/skills"
AGENTS_SKILLS="$HOME/.agents/skills"
CODEX_SKILLS="$HOME/.codex/skills"
CLAUDE_CMDS="$HOME/.claude/commands"   # commands are Claude-only; Codex ignores
OPENCODE_CMDS="${XDG_CONFIG_HOME:-$HOME/.config}/opencode/commands"
CLAUDE_HOOKS="$HOME/.claude/hooks"     # hooks are Claude-only
CLAUDE_SCRIPTS="$HOME/.claude/scripts" # referenced by hook commands in settings.json
CLAUDE_HOME="$HOME/.claude"            # CLAUDE.md fragments, pulled in via @name.md
CLAUDE_RULES="$HOME/.claude/rules"     # path-scoped rules
CODEX_HOME="$HOME/.codex"              # Codex global config root
PI_HOME="$HOME/.pi/agent"              # Pi global config root
OPENCODE_HOME="${XDG_CONFIG_HOME:-$HOME/.config}/opencode"

# Which claude-md/machines/<name>.md to bake into Pi/opencode AGENTS.md.
MACHINE="${MACHINE:-default}"

# Per-FILE links, never a whole-dir link: ~/.claude/hooks and ~/.claude itself hold
# machine-local files this repo does not own, and a dir symlink would hide them.

# backups go OUTSIDE the skill dirs — a *.bak left inside gets discovered as a
# duplicate skill by both Claude Code and Codex.
BACKUP="$HOME/.agent-skills-backup"

link() { # link <src> <dst>
  local src="$1" dst="$2"
  if [ -e "$dst" ] && [ ! -L "$dst" ]; then
    mkdir -p "$BACKUP"
    mv "$dst" "$BACKUP/$(basename "$(dirname "$dst")")-$(basename "$dst").bak"
    echo "backed up existing $dst -> $BACKUP/"
  fi
  ln -sfn "$src" "$dst"
  echo "linked $dst -> $src"
}

gen() { # gen <dst> <fragment...> — writes a generated (concatenated) file
  local dst="$1"
  shift
  if [ -e "$dst" ] && ! grep -q "$GEN_MARK" "$dst" 2>/dev/null; then
    mkdir -p "$BACKUP"
    mv "$dst" "$BACKUP/$(basename "$(dirname "$dst")")-$(basename "$dst").bak"
    echo "backed up existing $dst -> $BACKUP/"
  fi
  {
    echo "$GEN_MARK"
    for f in "$@"; do
      echo
      cat "$f"
    done
  } >"$dst"
  echo "wrote $dst (generated from fragments)"
}

GEN_MARK="<!-- generated by agent-skills/bin/link.sh — edit fragments, re-run -->"

mkdir -p "$CLAUDE_SKILLS" "$AGENTS_SKILLS" "$CODEX_SKILLS" "$CLAUDE_CMDS" "$CLAUDE_HOOKS" "$CLAUDE_SCRIPTS" "$CLAUDE_RULES" "$CODEX_HOME" "$PI_HOME" "$OPENCODE_CMDS"

for d in "$REPO"/skills/*/; do
  name="$(basename "$d")"
  link "$d" "$CLAUDE_SKILLS/$name"
  link "$d" "$AGENTS_SKILLS/$name"
  link "$d" "$CODEX_SKILLS/$name"
done

for f in "$REPO"/commands/*.md; do
  [ -e "$f" ] || continue
  link "$f" "$CLAUDE_CMDS/$(basename "$f")"
  link "$f" "$OPENCODE_CMDS/$(basename "$f")"
done

for f in "$REPO"/hooks/*.py "$REPO"/hooks/*.sh; do
  [ -e "$f" ] || continue
  link "$f" "$CLAUDE_HOOKS/$(basename "$f")"
done

# Hook commands in settings.json call these by absolute path, so they have to
# exist under ~/.claude/scripts on every machine.
for f in "$REPO"/scripts/*; do
  [ -e "$f" ] || continue
  link "$f" "$CLAUDE_SCRIPTS/$(basename "$f")"
done

# code-comments.md is path-scoped and belongs in rules/, not here — linking it
# into ~/.claude/ as well would load it unconditionally and defeat the scoping.
# opencode-header.md is opencode-only (baked into its generated AGENTS.md).
for f in "$REPO"/claude-md/*.md; do
  [ -e "$f" ] || continue
  [ "$(basename "$f")" = "code-comments.md" ] && continue
  [ "$(basename "$f")" = "opencode-header.md" ] && continue
  link "$f" "$CLAUDE_HOME/$(basename "$f")"
done

# Per-machine section. entry/CLAUDE.md @imports it unconditionally, so it has
# to resolve even on a box with no profile of its own (MACHINE=default).
link "$REPO/claude-md/machines/$MACHINE.md" "$CLAUDE_HOME/machine.md"

# Path-scoped rules load only when Claude reads a matching file.
link "$REPO/claude-md/code-comments.md" "$CLAUDE_RULES/code-comments.md"
rm -f "$CLAUDE_HOME/code-comments.md" "$HOME/.agents/AGENTS.md"

# Entry files: machine-local sections plus @imports of the shared fragments.
# Codex supports @path the same as CLAUDE.md, so neither tool needs a copy.
mkdir -p "$CODEX_HOME"
link "$REPO/entry/CLAUDE.md" "$CLAUDE_HOME/CLAUDE.md"
link "$REPO/entry/codex-AGENTS.md" "$CODEX_HOME/AGENTS.md"
rm -f "$CODEX_HOME/RTK.md"

# Pi and opencode have no @file imports: their AGENTS.md is generated by
# concatenating the fragments (machine profile first). opencode auto-loads
# skills from ~/.claude/skills and ~/.agents/skills, so it needs no skill links.
gen "$PI_HOME/AGENTS.md" \
  "$REPO/claude-md/machines/$MACHINE.md" \
  "$REPO/claude-md/operating.md" \
  "$REPO/claude-md/writing.md" \
  "$REPO/claude-md/code-comments.md" \
  "$REPO/claude-md/intercomms.md" \
  "$REPO/claude-md/RTK.md"

gen "$OPENCODE_HOME/AGENTS.md" \
  "$REPO/claude-md/opencode-header.md" \
  "$REPO/claude-md/machines/$MACHINE.md" \
  "$REPO/claude-md/operating.md" \
  "$REPO/claude-md/writing.md" \
  "$REPO/claude-md/code-comments.md" \
  "$REPO/claude-md/intercomms.md" \
  "$REPO/claude-md/RTK.md"

# Linked but never enabled: enabling on every machine would spawn one review
# session per box for the same week.
if [ -d /run/systemd/system ]; then
  mkdir -p "$HOME/.config/systemd/user"
  for f in "$REPO"/systemd/*.service "$REPO"/systemd/*.timer; do
    [ -e "$f" ] || continue
    link "$f" "$HOME/.config/systemd/user/$(basename "$f")"
  done
fi

echo "done. (MACHINE=$MACHINE for generated Pi/opencode AGENTS.md)"
echo "hooks still need wiring in ~/.claude/settings.json — see hooks/README.md"
echo "timers (one machine only):"
echo "  systemctl --user daemon-reload"
echo "  systemctl --user enable --now week-review.timer hourlog.timer"