#!/usr/bin/env python3
"""
Ralph DAG + tag-validation helpers (W3 smart gates).

Două responsabilități:
1. Tag validation heuristic — anti-silent-regression. Forțează tags pe baza
   diff content (chiar dacă Opus le-a omis). Rulat ÎNAINTE de smart gate dispatch.
2. DAG topological sort — alege următorul story eligibil (passes/failed/blocked
   propagation). Rulat de ralph.sh la începutul fiecărei iterații.

CLI subcommands (apelate din ralph.sh):

    python3 ralph_dag.py infer-tags <story_id> <project_dir>
        → printează tags inferate (newline-separated) pe baza git diff HEAD~1.

    python3 ralph_dag.py next-story <prd.json>
        → printează story_id eligibil (DAG-aware) sau exit 1 dacă nimic.

    python3 ralph_dag.py mark-failed <prd.json> <story_id> <reason>
        → marchează story.failed=true cu motiv; propagă blocked la dependenți.

    python3 ralph_dag.py incr-retry <prd.json> <story_id>
        → +1 retries; dacă >=3, mark failed cu reason="max_retries"; print new count.

    python3 ralph_dag.py force-tags <prd.json> <story_id> <project_dir>
        → adaugă tags inferate DIN DIFF în story.tags (idempotent, deduplicat);
          dacă tags sunt vide după → fallback la "run-all" (NU modifică, doar print "EMPTY").
"""

import json
import re
import subprocess
import sys
from pathlib import Path
from typing import List, Optional


VALID_TAGS = {"ui", "db", "vercel", "refactor", "docs", "backend", "infra"}

# Heuristici diff → tag. Sortate stabil pentru determinism în teste.
UI_PATTERN = re.compile(r'\.(vue|tsx|jsx|html|css|scss|svelte)$', re.IGNORECASE)
DB_MIGRATIONS = re.compile(r'(^|/)migrations?/', re.IGNORECASE)
DB_SQL = re.compile(r'\.sql$', re.IGNORECASE)


def infer_tags_from_paths(paths: List[str], has_vercel_json: bool = False) -> List[str]:
    """Pure function: dat list de file paths atinse + flag vercel.json, întoarce tags inferate.

    Returnează lista deduplicată, ordonată: ui, db, vercel.
    """
    tags = set()
    for p in paths:
        if not p:
            continue
        if UI_PATTERN.search(p):
            tags.add("ui")
        if DB_MIGRATIONS.search(p) or DB_SQL.search(p):
            tags.add("db")
    if has_vercel_json:
        tags.add("vercel")

    # Ordine stabilă pentru determinism (teste + diff-uri reproducibile)
    return sorted(tags, key=lambda t: ("ui", "db", "vercel").index(t) if t in ("ui", "db", "vercel") else 99)


def force_include_tags(existing_tags: List[str], diff_paths: List[str], has_vercel_json: bool) -> List[str]:
    """Combinator: existing tags ∪ inferred din diff. Filtrează la VALID_TAGS.

    Garanție anti-silent-regression: chiar dacă Opus a marcat story=docs, dacă diff
    atinge .vue/.tsx → ui e forțat. Story=docs care realmente atinge UI ar fi avut
    silent skip /qa.
    """
    inferred = infer_tags_from_paths(diff_paths, has_vercel_json)
    combined = []
    seen = set()
    for t in list(existing_tags) + inferred:
        if t in VALID_TAGS and t not in seen:
            combined.append(t)
            seen.add(t)
    return combined


def get_diff_paths(project_dir: Path, ref: str = "HEAD~1") -> List[str]:
    """Întoarce file paths din `git diff --name-only <ref>` în project_dir.

    Lista vidă dacă git nu e disponibil sau nu există commit anterior.
    """
    try:
        result = subprocess.run(
            ["git", "-C", str(project_dir), "diff", "--name-only", ref],
            capture_output=True, text=True, timeout=10,
        )
        if result.returncode != 0:
            # Fallback: diff vs HEAD (uncommitted changes) — util pe primul commit
            result = subprocess.run(
                ["git", "-C", str(project_dir), "diff", "--name-only", "HEAD"],
                capture_output=True, text=True, timeout=10,
            )
            if result.returncode != 0:
                return []
        return [p.strip() for p in result.stdout.splitlines() if p.strip()]
    except (subprocess.TimeoutExpired, FileNotFoundError):
        return []


def topological_eligible(stories: List[dict]) -> Optional[dict]:
    """Întoarce primul story eligibil (DAG-aware) — sau None dacă nimic.

    Eligibil = !passes ∧ !failed ∧ !blocked ∧ toate `dependsOn` au `passes==True`.
    Dacă story.dependsOn conține un ID `failed` → story-ul DEVINE blocked (mutat in-place).
    Sortare: priority asc.
    """
    by_id = {s.get("id"): s for s in stories}

    # Pas 1: propagă blocked dacă vreun dep e failed
    changed = True
    while changed:
        changed = False
        for s in stories:
            if s.get("passes") or s.get("failed") or s.get("blocked"):
                continue
            for dep_id in s.get("dependsOn") or []:
                dep = by_id.get(dep_id)
                if dep and (dep.get("failed") or dep.get("blocked")):
                    s["blocked"] = True
                    s["failureReason"] = f"blocked_by:{dep_id}"
                    changed = True
                    break

    # Pas 2: găsește story eligibil cu cea mai mică priority
    eligible = []
    for s in stories:
        if s.get("passes") or s.get("failed") or s.get("blocked"):
            continue
        deps = s.get("dependsOn") or []
        if all(by_id.get(d, {}).get("passes") for d in deps):
            eligible.append(s)

    if not eligible:
        return None
    eligible.sort(key=lambda s: (s.get("priority", 999), s.get("id", "")))
    return eligible[0]


def _load_prd(prd_path: Path) -> dict:
    with open(prd_path, encoding="utf-8") as f:
        return json.load(f)


def _save_prd(prd_path: Path, data: dict) -> None:
    """Atomic write — temp file + rename, evită corruption mid-write."""
    tmp = prd_path.with_suffix(".json.tmp")
    with open(tmp, "w", encoding="utf-8") as f:
        json.dump(data, f, indent=2, ensure_ascii=False)
    tmp.replace(prd_path)


def cmd_next_story(prd_path: Path) -> int:
    data = _load_prd(prd_path)
    stories = data.get("userStories", [])
    chosen = topological_eligible(stories)
    # Salvăm dacă topological_eligible a propagat blocked (mutație in-place)
    _save_prd(prd_path, data)
    if not chosen:
        return 1
    print(chosen.get("id", ""))
    return 0


def cmd_mark_failed(prd_path: Path, story_id: str, reason: str) -> int:
    data = _load_prd(prd_path)
    found = False
    for s in data.get("userStories", []):
        if s.get("id") == story_id:
            s["failed"] = True
            s["passes"] = False
            s["failureReason"] = reason or "unknown"
            found = True
            break
    if not found:
        print(f"Story {story_id} not found", file=sys.stderr)
        return 1
    # Propagate blocked la dependenți
    topological_eligible(data.get("userStories", []))
    _save_prd(prd_path, data)
    print(f"failed: {story_id} ({reason})")
    return 0


def cmd_incr_retry(prd_path: Path, story_id: str) -> int:
    data = _load_prd(prd_path)
    for s in data.get("userStories", []):
        if s.get("id") == story_id:
            s["retries"] = int(s.get("retries", 0)) + 1
            new = s["retries"]
            if new >= 3:
                s["failed"] = True
                s["failureReason"] = "max_retries"
                topological_eligible(data.get("userStories", []))
            _save_prd(prd_path, data)
            print(new)
            return 0
    print(f"Story {story_id} not found", file=sys.stderr)
    return 1


def cmd_force_tags(prd_path: Path, story_id: str, project_dir: Path) -> int:
    data = _load_prd(prd_path)
    diff_paths = get_diff_paths(project_dir)
    has_vercel = (project_dir / "vercel.json").exists()

    for s in data.get("userStories", []):
        if s.get("id") == story_id:
            existing = s.get("tags") or []
            forced = force_include_tags(existing, diff_paths, has_vercel)
            s["tags"] = forced
            _save_prd(prd_path, data)
            if not forced:
                print("EMPTY")  # ralph.sh interpretează ca run-all-gates fallback
            else:
                for t in forced:
                    print(t)
            return 0
    print(f"Story {story_id} not found", file=sys.stderr)
    return 1


def cmd_infer_tags(story_id: str, project_dir: Path) -> int:
    """Variant care NU modifică prd.json — doar print tags inferate din diff curent."""
    diff_paths = get_diff_paths(project_dir)
    has_vercel = (project_dir / "vercel.json").exists()
    inferred = infer_tags_from_paths(diff_paths, has_vercel)
    for t in inferred:
        print(t)
    return 0 if inferred else 1


def main() -> int:
    if len(sys.argv) < 2:
        print(__doc__)
        return 2
    cmd = sys.argv[1]
    args = sys.argv[2:]
    try:
        if cmd == "next-story" and len(args) == 1:
            return cmd_next_story(Path(args[0]))
        if cmd == "mark-failed" and len(args) == 3:
            return cmd_mark_failed(Path(args[0]), args[1], args[2])
        if cmd == "incr-retry" and len(args) == 2:
            return cmd_incr_retry(Path(args[0]), args[1])
        if cmd == "force-tags" and len(args) == 3:
            return cmd_force_tags(Path(args[0]), args[1], Path(args[2]))
        if cmd == "infer-tags" and len(args) == 2:
            return cmd_infer_tags(args[0], Path(args[1]))
        print(f"Unknown command: {cmd}", file=sys.stderr)
        print(__doc__, file=sys.stderr)
        return 2
    except FileNotFoundError as exc:
        print(f"File not found: {exc}", file=sys.stderr)
        return 3
    except json.JSONDecodeError as exc:
        print(f"Invalid JSON: {exc}", file=sys.stderr)
        return 3


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