"""
Unified sync script: agent-config/ is the source of truth.

Synchronizes:
- agent-config/ -> .cursor/, .agents/ (for Cursor / Antigravity)
- agent-config/rules/ -> CLAUDE.md, CLAUDE.local.md
- agent-config/skills/ -> .claude/skills/
- agent-config/ignore -> .cursorignore, .aiignore, .claudeignore

Run: make sync
"""

import re
import shutil
import sys
from pathlib import Path

FRONTMATTER_PATTERN = re.compile(r"^---\n.*?\n---\n?", re.DOTALL)

ORDERED_RULES = [
    "base.mdc",
    "node.mdc",
    "web.mdc",
    "api-routing-and-module-layout.mdc",
    "architecture-map.mdc",
    "ui/css-policy.mdc",
    "ui/keybinding-propagation-policy.mdc",
    "ui/modal-escape-policy.mdc",
    "ui/z-index-layer-policy.mdc",
]

CLAUDE_MD_HEADER = """\
<!-- This file is auto-generated by scripts/sync_agent_config.py from agent-config/rules/ -->
<!-- Do not edit directly. To update, run: make sync -->
"""


def sync_directories(src_dir: Path, dst_dir: Path) -> None:
    """
    Synchronize src_dir to dst_dir, mirroring its content.
    Similar to rsync -av --delete.
    """
    if not src_dir.exists():
        print(f"Error: Source directory {src_dir} does not exist.")
        sys.exit(1)

    dst_dir.mkdir(parents=True, exist_ok=True)

    src_items = {p.relative_to(src_dir) for p in src_dir.rglob("*")}
    dst_items = {p.relative_to(dst_dir) for p in dst_dir.rglob("*")}

    for item in sorted(dst_items - src_items, reverse=True):
        p = dst_dir / item
        if p.is_dir():
            shutil.rmtree(p)
            print(f"Removed directory: {p}")
        else:
            p.unlink()
            print(f"Removed file: {p}")

    for item in sorted(src_items):
        src_p = src_dir / item
        dst_p = dst_dir / item

        if src_p.is_dir():
            dst_p.mkdir(parents=True, exist_ok=True)
        else:
            src_stat = src_p.stat()
            dst_stat = dst_p.stat() if dst_p.exists() else None
            if dst_stat is None or src_stat.st_mtime > dst_stat.st_mtime or src_stat.st_size != dst_stat.st_size:
                dst_p.parent.mkdir(parents=True, exist_ok=True)
                shutil.copy2(src_p, dst_p)
                print(f"Synced: {item}")


def strip_frontmatter(text: str) -> str:
    return FRONTMATTER_PATTERN.sub("", text, count=1).strip()


def build_claude_md(rules_dir: Path, output_path: Path) -> None:
    sections = []
    for rule_rel in ORDERED_RULES:
        rule_path = rules_dir / rule_rel
        if not rule_path.exists():
            print(f"Error: Rule file not found: {rule_path}", file=sys.stderr)
            sys.exit(1)
        content = strip_frontmatter(rule_path.read_text(encoding="utf-8"))
        if content:
            sections.append(content)

    body = "\n\n".join(sections)
    output = CLAUDE_MD_HEADER + "\n" + body + "\n"
    output_path.write_text(output, encoding="utf-8", newline="\n")
    print(f"Generated: {output_path.name}")


def build_claude_local_md(rules_dir: Path, output_path: Path) -> None:
    local_rule = rules_dir / "base.local.mdc"
    if not local_rule.exists():
        return
    content = strip_frontmatter(local_rule.read_text(encoding="utf-8"))
    output_path.write_text(content + "\n", encoding="utf-8", newline="\n")
    print(f"Generated: {output_path.name}")


def copy_ignore_file(project_root: Path, src: Path, dst_name: str) -> None:
    """Copy agent-config/ignore (master) to dst_name at project root."""
    dst = project_root / dst_name
    if src.exists():
        shutil.copy2(src, dst)
        print(f"Copied: agent-config/ignore -> {dst_name}")
    elif dst.exists():
        dst.unlink()
        print(f"Removed: {dst_name} (source agent-config/ignore missing)")


def main() -> None:
    project_root = Path(__file__).resolve().parent.parent
    agent_config = project_root / "agent-config"
    rules_dir = agent_config / "rules"
    skills_src = agent_config / "skills"
    ignore_src = agent_config / "ignore"

    if not agent_config.exists():
        print(f"Error: agent-config/ not found at {agent_config}")
        sys.exit(1)

    print("Synchronizing from agent-config/ (source of truth)...")

    # agent-config/rules/ -> .cursor/rules/, .agents/rules/
    cursor_rules = project_root / ".cursor" / "rules"
    agent_rules = project_root / ".agents" / "rules"
    sync_directories(rules_dir, cursor_rules)
    print("Synced: agent-config/rules/ -> .cursor/rules/")
    sync_directories(rules_dir, agent_rules)
    print("Synced: agent-config/rules/ -> .agents/rules/")

    # agent-config/skills/ -> .cursor/skills/, .agents/skills/, .claude/skills/
    cursor_skills = project_root / ".cursor" / "skills"
    agent_skills = project_root / ".agents" / "skills"
    claude_skills = project_root / ".claude" / "skills"
    sync_directories(skills_src, cursor_skills)
    print("Synced: agent-config/skills/ -> .cursor/skills/")
    sync_directories(skills_src, agent_skills)
    print("Synced: agent-config/skills/ -> .agents/skills/")
    sync_directories(skills_src, claude_skills)
    print("Synced: agent-config/skills/ -> .claude/skills/")

    # agent-config/rules/ -> CLAUDE.md, CLAUDE.local.md
    build_claude_md(rules_dir, project_root / "CLAUDE.md")
    build_claude_local_md(rules_dir, project_root / "CLAUDE.local.md")

    # agent-config/ignore -> .cursorignore, .aiignore, .claudeignore
    copy_ignore_file(project_root, ignore_src, ".cursorignore")
    copy_ignore_file(project_root, ignore_src, ".aiignore")
    copy_ignore_file(project_root, ignore_src, ".claudeignore")

    print("Done.")


if __name__ == "__main__":
    main()