#!/usr/bin/env bash

# The manual this machine hands an agent.
#
# skills/ and .agents/skills/panama exist because an agent asked to do anything
# on a Panama desktop will otherwise infer it from the source and get half of it
# wrong. That only helps if what the skills say is true -- and a skill is worse
# than no skill when it is stale, because an agent believes it verbatim and does
# not check. Prose about design cannot be pinned; the things a skill names can
# be, so this checks every one of them:
#
#   1. The three skills load: SKILL.md with frontmatter whose name is the
#      directory's, and a description, which is the only part of a skill the
#      loader reads before deciding to open it.
#   2. Every command, path and variable a skill names in backticks resolves.
#      That is a convention on the prose -- name things exactly, in backticks --
#      and it is how they should be written anyway.
#   3. The delivery works: link-skills is a stage, in the right place, and the
#      personal manifest hands both shared skill homes to the linkdir kind.
#
# Sections 1 and 2 report clearly and keep going when a skill is not written
# yet, so this contract is useful while the skills are still being authored.

set -uo pipefail

repo_dir="$(cd "$(dirname "${BASH_SOURCE[0]}")/../.." && pwd)"
installer="$repo_dir/install"
linker="$repo_dir/setup/scripts/link-skills"
user_linker="$repo_dir/setup/scripts/link-user"
manifest="$repo_dir/user/manifest"

findings=()
note() { findings+=("$1"); }

# Every directory under skills/ ships to every machine. The project-level
# panama skill stays in this repository and needs no home-directory delivery.
SKILL_DIRS=()
for directory in "$repo_dir"/skills/*; do
    [[ -d "$directory" ]] && SKILL_DIRS+=("${directory#"$repo_dir"/}")
done
SKILL_DIRS+=(.agents/skills/panama)

# The project skill has one agent-neutral source. Claude gets a compatibility
# symlink, while Codex and other Agent Skills readers use .agents directly.
[[ -L "$repo_dir/.claude/skills/panama" ]] \
    || note '.claude/skills/panama is not a compatibility symlink to the agent-neutral source'
[[ "$(readlink -f "$repo_dir/.claude/skills/panama" 2>/dev/null)" == \
   "$(readlink -f "$repo_dir/.agents/skills/panama" 2>/dev/null)" ]] \
    || note '.claude and .agents resolve the project panama skill differently'

# ── 1. Each skill loads ─────────────────────────────────────────────────────

present=()
for relative in "${SKILL_DIRS[@]}"; do
    directory="$repo_dir/$relative"
    file="$directory/SKILL.md"

    if [[ ! -d "$directory" ]]; then
        note "$relative does not exist yet, so nothing there can be checked"
        continue
    fi
    if [[ ! -r "$file" ]]; then
        note "$relative has no readable SKILL.md, so the loader ignores it"
        continue
    fi
    present+=("$directory")

    # Frontmatter is the first --- delimited block, and a skill without one is
    # not a skill: agent loaders skip the directory entirely.
    frontmatter="$(awk 'NR==1 { if ($0 != "---") exit 1; next } $0 == "---" { exit } { print }' "$file")"
    if [[ -z "$frontmatter" ]]; then
        note "$relative/SKILL.md does not open with a --- frontmatter block"
        continue
    fi

    declared="$(sed -n 's/^name:[[:space:]]*//p' <<<"$frontmatter" | head -1)"
    description="$(sed -n 's/^description:[[:space:]]*//p' <<<"$frontmatter" | head -1)"

    [[ "$declared" == "$(basename "$directory")" ]] \
        || note "$relative/SKILL.md declares name '$declared', which is not its directory"
    [[ -n "$description" ]] \
        || note "$relative/SKILL.md has no description, so nothing ever decides to load it"
done

# ── 2. Every claim resolves ─────────────────────────────────────────────────
#
# A skill points rather than duplicates, so almost everything it says is a
# pointer -- and a pointer is exactly the kind of claim that rots silently. The
# rule: anything in backticks that looks like a command, a path in this
# repository, an environment variable or a panama-action verb must exist.

if (( ${#present[@]} == 0 )); then
    printf 'skills contract: no skill is written yet; claim checking skipped\n' >&2
else
    while IFS= read -r claim; do
        [[ -n "$claim" ]] && note "$claim"
    done < <(python3 - "$repo_dir" "${present[@]}" <<'PY'
import os
import re
import subprocess
import sys

repo, directories = sys.argv[1], sys.argv[2:]
findings = []


def read(path):
    with open(path, encoding="utf-8") as handle:
        return handle.read()


# What bin/panama actually dispatches, read from the dispatcher itself rather
# than from usage(), which is prose and can drift the same way a skill can.
subcommands = set(re.findall(r"^\s+([a-z][a-z-]*)\)\s*shift", read(os.path.join(repo, "bin/panama")), re.M))

# panama-action's verbs, from the one case statement that dispatches them.
action = read(os.path.join(repo, "config/dot/quickshell/scripts/panama-action"))
verbs = set()
for match in re.finditer(r"^\s+([a-z][a-z0-9|-]*)\)", action.split('case "$action" in', 1)[-1], re.M):
    verbs.update(match.group(1).split("|"))

tools = set(os.listdir(os.path.join(repo, "bin")))
tools |= set(os.listdir(os.path.join(repo, "config/dot/quickshell/scripts")))

# Every tracked file, so a path written the way the surrounding sentence reads
# -- `services/SettingsRoutes.qml`, not the whole path from the root -- still
# has to resolve to exactly one real file.
tracked = []
for root, names, files in os.walk(repo):
    names[:] = [n for n in names if n not in (".git", "__pycache__", "node_modules")]
    for name in files:
        tracked.append(os.path.relpath(os.path.join(root, name), repo))

seen_variables = {}


def used_outside_the_skills(name):
    """An environment variable a skill names has to be one the tree reads."""
    if name not in seen_variables:
        found = subprocess.run(
            ["grep", "-rlF", "--exclude-dir=.git", "--", name, repo],
            capture_output=True, text=True,
        ).stdout.split()
        seen_variables[name] = any(
            not any(path.startswith(directory) for directory in directories) for path in found
        )
    return seen_variables[name]


def check(token, where):
    token = token.strip()
    if not token:
        return
    words = token.split()
    head = words[0]

    for variable in re.findall(r"\bPANAMA_[A-Z0-9_]+\b", token):
        if not used_outside_the_skills(variable):
            findings.append(f"{where} names {variable}, which nothing in the tree reads")

    if head == "panama" and len(words) > 1:
        subcommand = words[1]
        if re.fullmatch(r"[a-z][a-z-]*", subcommand) and subcommand not in subcommands:
            findings.append(f"{where} names `panama {subcommand}`, which the dispatcher does not handle")
        return

    if head == "panama-action" and len(words) > 1:
        verb = words[1]
        if re.fullmatch(r"[a-z][a-z0-9-]*", verb) and verb not in verbs:
            findings.append(f"{where} names the panama-action verb '{verb}', which it does not dispatch")
        return

    if re.fullmatch(r"panama-[a-z0-9-]+", head) and head not in tools:
        # An invocation has to be a command. A bare name may be something else
        # Panama calls by that name -- a doctor check group, a systemd unit --
        # and then it only has to be real somewhere in the tree.
        if len(words) > 1:
            findings.append(f"{where} runs `{head}`, which is not in bin/ or the quickshell scripts")
        elif not used_outside_the_skills(head):
            findings.append(f"{where} names '{head}', which appears nowhere else in the tree")
        return

    # A repository path. Home paths and URLs are runtime, not tracked here, and
    # a glob is a description of several files rather than one claim.
    if "/" in head and not head.startswith(("~", "/", "http", "$")):
        path = re.sub(r"/\*+$", "", head.rstrip("/"))
        if "*" in path or not path:
            return
        if os.path.exists(os.path.join(repo, path)):
            return
        matches = [candidate for candidate in tracked if candidate.endswith("/" + path)]
        if not matches:
            findings.append(f"{where} points at {path}, which is not in the repository")
        elif len(matches) > 1:
            findings.append(f"{where} points at {path}, which is several files; name it from the root")


backticked = re.compile(r"`([^`\n]+)`")
for directory in directories:
    for root, _, names in os.walk(directory):
        for name in sorted(names):
            if not name.endswith(".md"):
                continue
            path = os.path.join(root, name)
            where = os.path.relpath(path, repo)
            for token in backticked.findall(read(path)):
                check(token, where)

print("\n".join(sorted(set(findings))))
PY
    )
fi

# ── 3. The stage exists and does what it says ───────────────────────────────

if [[ ! -x "$linker" ]]; then
    note 'setup/scripts/link-skills is missing or not executable, so no machine gets the skills'
else
    work="$(mktemp -d)"
    trap 'rm -rf "$work"' EXIT

    # A checkout and a home of its own. Never the real ones: these are somebody's
    # live agent setup, and a contract that broke them mid-session would be worse
    # than the bug it was looking for.
    checkout="$work/Panama"
    home="$work/home"
    mkdir -p "$checkout/setup/scripts" "$checkout/skills/shipped" "$home/.claude" "$home/.agents"
    cp "$linker" "$checkout/setup/scripts/link-skills"
    printf 'a shipped skill\n' >"$checkout/skills/shipped/SKILL.md"

    # The machine as it is before this stage ever ran: one whole-directory
    # symlink, which is what link-user used to leave here.
    mkdir -p "$work/personal"
    ln -s "$work/personal" "$home/.claude/skills"
    ln -s "$work/personal" "$home/.agents/skills"

    run() { HOME="$home" PANAMA_PATH="$checkout" "$checkout/setup/scripts/link-skills" >"$work/log" 2>&1; }

    if ! run; then
        note "link-skills failed against a throwaway home: $(tail -1 "$work/log")"
    fi

    [[ -d "$home/.claude/skills" && ! -L "$home/.claude/skills" ]] \
        || note 'link-skills left ~/.claude/skills a symlink, so nothing else can be linked into it'
    [[ -L "$home/.claude/skills/shipped" ]] \
        || note 'link-skills did not link each shipped skill as a child of ~/.claude/skills'
    [[ -d "$home/.agents/skills" && ! -L "$home/.agents/skills" ]] \
        || note 'link-skills left ~/.agents/skills a symlink, so shipped and personal skills cannot coexist'
    [[ -L "$home/.agents/skills/shipped" ]] \
        || note 'link-skills did not link each shipped skill as a child of ~/.agents/skills'
    grep -q 'Agent skills: 1 linked' "$work/log" \
        || note 'link-skills does not report how many skills it linked'

    # A real directory at a shipped skill's name is somebody's work: it moves to
    # config/old rather than being deleted, the same promise the other stages
    # make. A symlink is not, and must not accumulate there.
    for skill_home in "$home/.claude/skills" "$home/.agents/skills"; do
        rm -f "$skill_home/shipped"
        mkdir -p "$skill_home/shipped"
        printf 'installed by hand\n' >"$skill_home/shipped/SKILL.md"
        mkdir -p "$skill_home/untouched"
    done

    run
    [[ "$(grep -rl 'installed by hand' "$checkout/config/old" 2>/dev/null | wc -l)" == 2 ]] \
        || note 'link-skills did not preserve real skills from both agent homes'
    for skill_home in "$home/.claude/skills" "$home/.agents/skills"; do
        [[ -d "$skill_home/untouched" ]] \
            || note "link-skills removed an unshipped skill from $skill_home"
    done

    before="$(find "$checkout/config/old" | wc -l)"
    run
    after="$(find "$checkout/config/old" | wc -l)"
    [[ "$before" == "$after" ]] \
        || note 'link-skills backs up its own symlinks, so config/old grows on every upgrade'
fi

# ── The stage runs, in the one order that gives personal skills precedence ──

# Checked against every literal per-role stage list. The server list carries
# no link-skills at all (its three skills operate the desktop), so the demand
# is: at least one list runs it, and any list that runs it runs it between
# link-dotfiles and link-user.
python3 - "$installer" <<'PY' || note 'link-skills is not in STAGES between link-dotfiles and link-user'
import re, sys
lines = [l.strip() for l in open(sys.argv[1], encoding="utf-8")
         if l.strip().startswith("STAGES=(") and "upgrade_stages" not in l]
anywhere = False
for line in lines:
    stages = re.findall(r"[\w-]+", line)
    if "link-skills" not in stages:
        continue
    anywhere = True
    if not stages.index("link-dotfiles") < stages.index("link-skills") < stages.index("link-user"):
        raise SystemExit(1)
if not anywhere:
    raise SystemExit(1)
PY

# An upgrade drops stages by name. link-skills must not be one of them --
# update-command-contract proves that by running the installer; this says why.
if sed -n '/upgrade_stages=()/,/STAGES=("${upgrade_stages\[@\]}")/p' "$installer" | grep -q 'link-skills'; then
    note 'install --upgrade filters link-skills out, so an existing machine never gets the skills'
fi

# ── The personal half hands the directory over ──────────────────────────────

grep -qE '^\s*linkdir\s+agents/skills\s+~/\.claude/skills\s*$' "$manifest" \
    || note 'the manifest does not use linkdir for ~/.claude/skills, so personal skills would replace the directory'
grep -qE '^\s*linkdir\s+agents/skills\s+~/\.agents/skills\s*$' "$manifest" \
    || note 'the manifest does not use linkdir for ~/.agents/skills, so personal skills would replace shipped skills'
grep -q 'linkdir)' "$user_linker" \
    || note 'link-user does not implement the linkdir kind the manifest asks for'
grep -q 'linkdir' "$repo_dir/user/README.md" \
    || note 'user/README.md does not document the linkdir kind'

if (( ${#findings[@]} > 0 )); then
    printf 'skills contract: %d finding(s)\n' "${#findings[@]}" >&2
    printf '  - %s\n' "${findings[@]}" >&2
    exit 1
fi

printf 'skills contract: PASS (%d skill(s) checked)\n' "${#present[@]}"