#!/usr/bin/env python3
"""按分支改动选择最小直接检查：host 实施中的 make 目标子集（完整套件仍以 CI 为准）。

用法：test_affected.py [--base REF] [--dry-run]
  base：--base，否则环境变量 BASE，否则当前分支卡片的 immediate_target（task_pr_check 助手），
  再否则 origin/main；裸分支名在 origin/<name> 存在时解析为 origin/<name>。

改动路径 = `git diff <merge-base>...HEAD` ∪ 未提交的已跟踪改动（相对 HEAD）。路径到目标：
  scripts/** tests/** .gitea/** policy/** Makefile AGENTS.md AGENT-EXECUTION.md PROJECT.md → test-governance
  modules/{core,backend,frontend,ui} → test-{core,backend,frontend,ui}；deps/agent-command → test-agentcmd；
  deps/agent-{intent,native,squad} → test-libs；gitlink 本身或 .gitmodules → test-pins；
  modules/** 或 scripts/lint-boundaries.sh → test-boundaries；其余（.task/**、docs/**、其他 *.md）不选。
选中任一目标时先跑 test-worktree；单次 `make <targets>` 执行，退出码随 make。

退出码：make 的退出码；无目标或 --dry-run 为 0；用法/ref 错误为 2。仅使用标准库。
"""
import argparse
import os
import subprocess
import sys

DEFAULT_BASE = "origin/main"
EXIT_USAGE = 2
GITLINK_MODE = "160000"
ORDER = ("test-governance", "test-boundaries", "test-pins", "test-libs", "test-core",
         "test-backend", "test-frontend", "test-ui", "test-agentcmd")
GOVERNANCE_DIRS = ("scripts/", "tests/", ".gitea/", "policy/")
GOVERNANCE_FILES = ("Makefile", "AGENTS.md", "AGENT-EXECUTION.md", "PROJECT.md")
COMPONENTS = {
    "modules/core": "test-core",
    "modules/backend": "test-backend",
    "modules/frontend": "test-frontend",
    "modules/ui": "test-ui",
    "deps/agent-command": "test-agentcmd",
    "deps/agent-intent": "test-libs",
    "deps/agent-native": "test-libs",
    "deps/agent-squad": "test-libs",
}


class Stop(Exception):
    pass


def git(*args):
    proc = subprocess.run(["git", *args], capture_output=True, text=True, encoding="utf-8", errors="replace")
    if proc.returncode != 0:
        raise Stop(f"git {' '.join(args)} failed: {proc.stderr.strip() or proc.returncode}")
    return proc.stdout


def ref_exists(ref):
    return subprocess.run(["git", "rev-parse", "--verify", "--quiet", f"{ref}^{{commit}}"],
                          capture_output=True).returncode == 0


def card_target():
    """当前分支卡片的 immediate_target；无分支/无助手/无卡时返回 None。"""
    try:
        sys.path.insert(0, os.path.dirname(os.path.abspath(__file__)))
        import task_pr_check
        meta, text = task_pr_check.branch_meta(task_pr_check.current_branch(), "main")
    except Exception:
        return None
    return meta.get("immediate_target") if text is not None else None


def resolve_base(requested):
    name = (requested or os.environ.get("BASE", "")).strip() or card_target() or DEFAULT_BASE
    if not name.startswith("origin/") and ref_exists(f"refs/remotes/origin/{name}"):
        name = f"origin/{name}"
    if not ref_exists(name):
        raise Stop(f"base {name} does not resolve to a commit")
    return name


def raw_changes(*diff_args):
    """{path: is_gitlink}，取自 `git diff --raw -z --no-renames`。"""
    out = git("diff", "--raw", "-z", "--no-renames", *diff_args)
    fields = out.split("\0")
    changes = {}
    for meta, path in zip(fields[0::2], fields[1::2]):
        modes = meta.lstrip(":").split()[:2]
        changes[path] = changes.get(path, False) or GITLINK_MODE in modes
    return changes


def changed_paths(base):
    merge_base = git("merge-base", base, "HEAD").strip()
    changes = raw_changes(merge_base, "HEAD")
    for path, gitlink in raw_changes("HEAD").items():
        changes[path] = changes.get(path, False) or gitlink
    return changes


def targets_for(path, gitlink):
    found = set()
    if path.startswith(GOVERNANCE_DIRS) or path in GOVERNANCE_FILES:
        found.add("test-governance")
    for prefix, target in COMPONENTS.items():
        if path == prefix or path.startswith(prefix + "/"):
            found.add(target)
    if gitlink or path == ".gitmodules":
        found.add("test-pins")
    if path.startswith("modules/") or path == "scripts/lint-boundaries.sh":
        found.add("test-boundaries")
    return found


def select(changes):
    found = set()
    for path, gitlink in changes.items():
        found |= targets_for(path, gitlink)
    return ["test-worktree", *(t for t in ORDER if t in found)] if found else []


def main(argv=None):
    parser = argparse.ArgumentParser(prog="test_affected.py", description="按分支改动运行最小直接检查")
    parser.add_argument("--base")
    parser.add_argument("--dry-run", action="store_true")
    args = parser.parse_args(argv)
    try:
        os.chdir(git("rev-parse", "--show-toplevel").strip())
        base = resolve_base(args.base)
        changes = changed_paths(base)
    except Stop as stop:
        print(f"[affected] ERROR {stop}")
        return EXIT_USAGE
    targets = select(changes)
    print(f"[affected] base={base} changed={len(changes)} targets={','.join(targets) or 'none'}", flush=True)
    if not targets:
        print("[affected] nothing to test")
        return 0
    if args.dry_run:
        print(f"[affected] dry-run: make {' '.join(targets)}")
        return 0
    return subprocess.run(["make", *targets]).returncode


if __name__ == "__main__":
    sys.exit(main())