"""QA Agent - Handles code review, testing, linting, and merge operations."""

import os
import re
import subprocess
from pathlib import Path

import git

from app_factory.core.claude_client import ClaudeSDKClient


class QAAgent:
    """Reviews code, runs tests, handles merge conflicts, merges worktrees to main."""

    def __init__(
        self,
        repo_path: str,
        api_key: str = None,
        auth_token: str = None,
        max_retries: int = 3,
        debug: bool = False,
        observability=None,
    ):
        """Initialize QAAgent.

        Args:
            repo_path: Path to the git repository.
            api_key: Optional API key. Falls back to ANTHROPIC_API_KEY env var.
            max_retries: Maximum QA-Dev bounce retries per task.
        """
        self.repo = git.Repo(repo_path)
        self.repo_path = Path(repo_path).resolve()
        self.max_retries = max_retries
        self._retry_counts: dict[str, int] = {}
        self._prompts_dir = Path(__file__).resolve().parent.parent / "prompts"
        self.observability = observability

        resolved_key = api_key or os.environ.get("ANTHROPIC_API_KEY")
        resolved_auth = auth_token or os.environ.get("ANTHROPIC_AUTH_TOKEN")
        self.client = ClaudeSDKClient(
            api_key=resolved_key,
            auth_token=resolved_auth,
            enable_debug=debug,
        )

    async def review_and_merge(self, task_id: str, worktree_path: str, task: dict = None) -> dict:
        """Full QA pipeline: rebase, lint, test, review, merge.

        Returns:
            dict with status and details. Status is one of:
            'merged', 'rebase_failed', 'lint_failed', 'tests_failed', 'review_failed'.
        """
        # 1. Rebase feature branch onto main
        rebase_result = await self.rebase_onto_main(worktree_path, task_id)
        if not rebase_result["success"]:
            self._increment_retry(task_id)
            return {
                "status": "rebase_failed",
                "conflicts": rebase_result.get("conflicts", []),
                "retry_count": self.get_retry_count(task_id),
            }

        # 2. Run linting
        lint_result = self.run_linter(worktree_path)
        if not lint_result["passed"]:
            self._increment_retry(task_id)
            return {
                "status": "lint_failed",
                "errors": lint_result["errors"],
                "warnings": lint_result["warnings"],
                "retry_count": self.get_retry_count(task_id),
            }

        # 3. Run tests
        test_result = self.run_tests(worktree_path)
        if not test_result["passed"]:
            self._increment_retry(task_id)
            return {
                "status": "tests_failed",
                "total": test_result["total"],
                "failures": test_result["failures"],
                "errors": test_result["errors"],
                "output": test_result["output"],
                "retry_count": self.get_retry_count(task_id),
            }

        # 4. Code review via Claude
        wt_repo = git.Repo(worktree_path)
        diff = wt_repo.git.diff("main", "--", ".")
        review_result = await self.code_review(diff, task=task)
        if not review_result["approved"]:
            self._increment_retry(task_id)
            return {
                "status": "review_failed",
                "issues": review_result["issues"],
                "summary": review_result["summary"],
                "retry_count": self.get_retry_count(task_id),
            }

        # 5. Merge to main
        merge_result = self.merge_to_main(worktree_path, task_id)
        if not merge_result["success"]:
            return {
                "status": "merge_failed",
                "error": merge_result.get("error", "Unknown merge error"),
            }

        return {
            "status": "merged",
            "commit_sha": merge_result["commit_sha"],
            "review_summary": review_result["summary"],
        }

    async def rebase_onto_main(self, worktree_path: str, task_id: str) -> dict:
        """Rebase the feature branch in the worktree onto main.

        Returns:
            dict with success bool and conflicts list.
        """
        wt_repo = git.Repo(worktree_path)
        try:
            wt_repo.git.fetch("origin", "main")
        except git.GitCommandError:
            pass  # fetch may fail in local-only repos; continue with local main

        try:
            wt_repo.git.rebase("main")
            return {"success": True, "conflicts": []}
        except git.GitCommandError:
            # Rebase failed — check for conflicts
            conflicts = self._get_conflict_files(wt_repo)
            if conflicts and self.auto_resolve_conflicts(worktree_path):
                return {"success": True, "conflicts": []}
            # Abort the failed rebase
            try:
                wt_repo.git.rebase("--abort")
            except git.GitCommandError:
                pass
            return {"success": False, "conflicts": conflicts}

    def run_linter(self, worktree_path: str) -> dict:
        """Run ruff linter on the worktree.

        Returns:
            dict with passed bool, errors list, and warnings list.
        """
        try:
            result = subprocess.run(
                ["ruff", "check", "."],
                cwd=worktree_path,
                capture_output=True,
                text=True,
                timeout=120,
            )
        except FileNotFoundError:
            return {"passed": True, "errors": [], "warnings": ["ruff not found, skipping lint"]}
        except subprocess.TimeoutExpired:
            return {"passed": False, "errors": ["Linter timed out"], "warnings": []}

        errors = []
        warnings = []
        for line in result.stdout.splitlines():
            line = line.strip()
            if not line or line.startswith("Found") or line.startswith("All checks"):
                continue
            # ruff output lines contain error codes like E501, W291, etc.
            if re.search(r"\b[A-Z]\d{3,4}\b", line):
                errors.append(line)
            elif line:
                warnings.append(line)

        passed = result.returncode == 0
        return {"passed": passed, "errors": errors, "warnings": warnings}

    def run_tests(self, worktree_path: str) -> dict:
        """Run pytest in the worktree.

        Returns:
            dict with passed bool, total/failures/errors counts, and raw output.
        """
        try:
            result = subprocess.run(
                ["python", "-m", "pytest", "-v", "--tb=short"],
                cwd=worktree_path,
                capture_output=True,
                text=True,
                timeout=300,
            )
        except FileNotFoundError:
            return {"passed": False, "total": 0, "failures": 0, "errors": 1,
                    "output": "pytest not found"}
        except subprocess.TimeoutExpired:
            return {"passed": False, "total": 0, "failures": 0, "errors": 1,
                    "output": "Test execution timed out"}

        output = result.stdout + result.stderr
        parsed = self.parse_test_results(output)
        parsed["output"] = output
        return parsed

    async def code_review(self, diff: str, task: dict = None) -> dict:
        """Review a diff using Claude for quality and security issues.

        Returns:
            dict with approved bool, issues list, and summary string.
        """
        template = self._load_template("qa_review.txt")
        task_context = ""
        if task:
            task_context = (
                f"Task ID: {task.get('id', 'N/A')}\n"
                f"Title: {task.get('title', 'N/A')}\n"
                f"Description: {task.get('description', 'N/A')}"
            )

        prompt = template.format(task_context=task_context, diff=diff)

        response = await self.client.complete(
            prompt=prompt,
            model="claude-sonnet-4-6",
            max_turns=100,
            observability=self.observability,
            agent_name="qa_agent",
            task_id=str(task.get("id", task.get("task_id", "review"))) if task else "review",
        )
        if self.observability:
            self.observability.log_token_usage(
                "qa_agent",
                str(task.get("id", task.get("task_id", "review"))) if task else "review",
                input_tokens=response.input_tokens,
                output_tokens=response.output_tokens,
                model="claude-sonnet-4-6",
            )

        text = response.text
        return self._parse_review_response(text)

    def merge_to_main(self, worktree_path: str, task_id: str) -> dict:
        """Merge the feature branch into main with --no-ff.

        Returns:
            dict with success bool and commit_sha.
        """
        branch_name = f"feature/task-{task_id}"
        try:
            self.repo.git.checkout("main")
            self.repo.git.merge("--no-ff", branch_name, m=f"Merge {branch_name}")
            commit_sha = self.repo.head.commit.hexsha
            return {"success": True, "commit_sha": commit_sha}
        except git.GitCommandError as e:
            return {"success": False, "commit_sha": None, "error": str(e)}

    def auto_resolve_conflicts(self, worktree_path: str) -> bool:
        """Try to auto-resolve simple merge conflicts.

        Returns True if all conflicts were resolved.
        """
        wt_repo = git.Repo(worktree_path)
        unmerged = wt_repo.index.unmerged_blobs()
        if not unmerged:
            return True

        for path in unmerged:
            file_path = os.path.join(worktree_path, path)
            if not os.path.exists(file_path):
                continue
            try:
                with open(file_path) as f:
                    content = f.read()
                # Accept "theirs" (incoming) for simple conflicts
                if "<<<<<<< " in content and "=======" in content and ">>>>>>> " in content:
                    resolved = re.sub(
                        r"<<<<<<< [^\n]*\n.*?=======\n(.*?)>>>>>>> [^\n]*\n",
                        r"\1",
                        content,
                        flags=re.DOTALL,
                    )
                    with open(file_path, "w") as f:
                        f.write(resolved)
                    wt_repo.index.add([path])
                else:
                    return False
            except Exception:
                return False

        try:
            wt_repo.git.rebase("--continue")
            return True
        except git.GitCommandError:
            return False

    def parse_test_results(self, output: str) -> dict:
        """Parse pytest output into structured results.

        Returns:
            dict with passed bool, total int, failures int, errors int.
        """
        # Match pytest summary line like "5 passed, 2 failed, 1 error"
        passed_count = 0
        failed_count = 0
        error_count = 0

        # Look for the summary line
        summary_match = re.search(
            r"=+\s*(.*?)\s*=+\s*$",
            output,
            re.MULTILINE,
        )
        if summary_match:
            summary_line = summary_match.group(1)
            p = re.search(r"(\d+)\s+passed", summary_line)
            f = re.search(r"(\d+)\s+failed", summary_line)
            e = re.search(r"(\d+)\s+error", summary_line)
            if p:
                passed_count = int(p.group(1))
            if f:
                failed_count = int(f.group(1))
            if e:
                error_count = int(e.group(1))

        total = passed_count + failed_count + error_count
        all_passed = failed_count == 0 and error_count == 0 and total > 0

        return {
            "passed": all_passed,
            "total": total,
            "failures": failed_count,
            "errors": error_count,
        }

    def get_retry_count(self, task_id: str) -> int:
        """Return QA retry count for a task."""
        return self._retry_counts.get(task_id, 0)

    def _increment_retry(self, task_id: str):
        """Increment the retry counter for a task."""
        self._retry_counts[task_id] = self._retry_counts.get(task_id, 0) + 1

    def _load_template(self, template_name: str) -> str:
        """Load a prompt template file from app_factory/prompts/."""
        path = self._prompts_dir / template_name
        return path.read_text()

    def _get_conflict_files(self, repo: git.Repo) -> list[str]:
        """Get list of conflicting files from a repo."""
        try:
            status_output = repo.git.status("--porcelain")
            conflicts = []
            for line in status_output.splitlines():
                if line.startswith("UU ") or line.startswith("AA "):
                    conflicts.append(line[3:].strip())
            return conflicts
        except git.GitCommandError:
            return []

    def _parse_review_response(self, text: str) -> dict:
        """Parse Claude's review response into structured data."""
        approved = False
        issues = []
        summary = ""

        for line in text.splitlines():
            line = line.strip()
            if line.upper().startswith("APPROVED:"):
                value = line.split(":", 1)[1].strip().lower()
                approved = value in ("true", "yes")
            elif line.startswith("- ["):
                # Parse issue lines like "- [severity: critical] description"
                issue_match = re.match(
                    r"-\s*\[severity:\s*(critical|warning|info)\]\s*(.*)",
                    line,
                    re.IGNORECASE,
                )
                if issue_match:
                    issues.append({
                        "severity": issue_match.group(1).lower(),
                        "description": issue_match.group(2).strip(),
                    })
            elif line.upper().startswith("SUMMARY:"):
                summary = line.split(":", 1)[1].strip()

        return {"approved": approved, "issues": issues, "summary": summary}