"""
PostgreSQL Database Manager — CRUD for jobs and audit logging
"""

import json
import os
import hashlib
import time
import psycopg2
from psycopg2.extras import RealDictCursor
from contextlib import contextmanager

DB_HOST = os.getenv('DB_HOST', 'localhost')
DB_PORT = int(os.getenv('DB_PORT', 5432))
DB_NAME = os.getenv('DB_NAME', 'pdf_checker')
DB_USER = os.getenv('DB_USER', 'pdf_checker')
DB_PASSWORD = os.getenv('DB_PASSWORD', 'dev_password')


@contextmanager
def get_conn():
    """Get a database connection (context manager)."""
    conn = psycopg2.connect(
        host=DB_HOST,
        port=DB_PORT,
        dbname=DB_NAME,
        user=DB_USER,
        password=DB_PASSWORD
    )
    try:
        yield conn
        conn.commit()
    except Exception:
        conn.rollback()
        raise
    finally:
        conn.close()


def create_job(job_id: str, filename: str, ip: str = None, api_key: str = None):
    """Create a new job record."""
    key_hash = hashlib.sha256(api_key.encode()).hexdigest()[:16] if api_key else None
    with get_conn() as conn:
        with conn.cursor() as cur:
            cur.execute(
                """INSERT INTO jobs (job_id, filename, status, api_key_hash, ip_address)
                   VALUES (%s, %s, 'queued', %s, %s)""",
                (job_id, filename, key_hash, ip)
            )


def update_job_status(job_id: str, status: str, result_json: dict = None,
                      score: int = None, grade: str = None,
                      total_issues: int = None, critical_count: int = None,
                      error_count: int = None, warning_count: int = None,
                      processing_time: float = None):
    """Update job status and optionally store results."""
    with get_conn() as conn:
        with conn.cursor() as cur:
            fields = ["status = %s"]
            values = [status]

            if result_json is not None:
                fields.append("result_json = %s")
                values.append(json.dumps(result_json))
            if score is not None:
                fields.append("score = %s")
                values.append(score)
            if grade is not None:
                fields.append("grade = %s")
                values.append(grade)
            if total_issues is not None:
                fields.append("total_issues = %s")
                values.append(total_issues)
            if critical_count is not None:
                fields.append("critical_count = %s")
                values.append(critical_count)
            if error_count is not None:
                fields.append("error_count = %s")
                values.append(error_count)
            if warning_count is not None:
                fields.append("warning_count = %s")
                values.append(warning_count)
            if processing_time is not None:
                fields.append("processing_time = %s")
                values.append(processing_time)
            if status == 'completed':
                fields.append("completed_at = NOW()")

            values.append(job_id)
            cur.execute(
                f"UPDATE jobs SET {', '.join(fields)} WHERE job_id = %s",
                values
            )


def get_job(job_id: str) -> dict:
    """Get a job by ID."""
    with get_conn() as conn:
        with conn.cursor(cursor_factory=RealDictCursor) as cur:
            cur.execute("SELECT * FROM jobs WHERE job_id = %s", (job_id,))
            row = cur.fetchone()
            return dict(row) if row else None


def list_jobs(limit: int = 50, offset: int = 0, status_filter: str = None) -> list:
    """List jobs with optional filtering."""
    with get_conn() as conn:
        with conn.cursor(cursor_factory=RealDictCursor) as cur:
            query = "SELECT job_id, filename, status, score, grade, total_issues, created_at, completed_at, processing_time FROM jobs"
            values = []
            if status_filter:
                query += " WHERE status = %s"
                values.append(status_filter)
            query += " ORDER BY created_at DESC LIMIT %s OFFSET %s"
            values.extend([limit, offset])
            cur.execute(query, values)
            return [dict(row) for row in cur.fetchall()]


def log_audit(job_id: str, action: str, details: dict = None, ip: str = None):
    """Log an audit event."""
    with get_conn() as conn:
        with conn.cursor() as cur:
            cur.execute(
                """INSERT INTO audit_log (job_id, action, details, ip_address)
                   VALUES (%s, %s, %s, %s)""",
                (job_id, action, json.dumps(details or {}), ip)
            )


def get_stats() -> dict:
    """Get aggregate statistics."""
    with get_conn() as conn:
        with conn.cursor(cursor_factory=RealDictCursor) as cur:
            cur.execute("""
                SELECT
                    COUNT(*) as total_jobs,
                    COUNT(*) FILTER (WHERE status = 'completed') as completed_jobs,
                    COUNT(*) FILTER (WHERE status = 'failed') as failed_jobs,
                    COUNT(*) FILTER (WHERE status = 'processing') as active_jobs,
                    ROUND(AVG(score) FILTER (WHERE score IS NOT NULL)) as avg_score,
                    ROUND(AVG(processing_time) FILTER (WHERE processing_time IS NOT NULL)::numeric, 2) as avg_processing_time
                FROM jobs
            """)
            return dict(cur.fetchone())


def dismiss_issue(job_id: str, issue_index: int, reason: str = None):
    """Record a dismissed/false-positive issue."""
    with get_conn() as conn:
        with conn.cursor() as cur:
            cur.execute(
                """INSERT INTO dismissed_issues (job_id, issue_index, reason)
                   VALUES (%s, %s, %s)
                   ON CONFLICT (job_id, issue_index) DO UPDATE
                   SET reason = EXCLUDED.reason, dismissed_at = NOW()""",
                (job_id, issue_index, reason)
            )


def undismiss_issue(job_id: str, issue_index: int):
    """Remove a dismissal record."""
    with get_conn() as conn:
        with conn.cursor() as cur:
            cur.execute(
                "DELETE FROM dismissed_issues WHERE job_id = %s AND issue_index = %s",
                (job_id, issue_index)
            )


def get_dismissed_indices(job_id: str) -> list:
    """Return list of dismissed issue indices for a job."""
    with get_conn() as conn:
        with conn.cursor() as cur:
            cur.execute(
                "SELECT issue_index FROM dismissed_issues WHERE job_id = %s ORDER BY issue_index",
                (job_id,)
            )
            return [row[0] for row in cur.fetchall()]