"""Analytics module — time-series metrics snapshots + chart data endpoints.

Records pipeline metrics every 15 minutes. Serves historical data for
Chart.js dashboard. Tracks source origin (agent/human/scraper) for
pipeline funnel visualization.

Priority 1 from Cory via Ganymede.
Epimetheus owns this module.
"""

import json
import logging
import re
from datetime import datetime, timezone

from . import config, db

logger = logging.getLogger("pipeline.analytics")


# ─── Snapshot recording ────────────────────────────────────────────────────


def record_snapshot(conn) -> dict:
    """Record a metrics snapshot. Called every 15 minutes by the pipeline daemon.

    Returns the snapshot dict for logging/debugging.
    """
    # Throughput (last hour)
    throughput = conn.execute(
        """SELECT COUNT(*) as n FROM audit_log
           WHERE timestamp > datetime('now', '-1 hour')
             AND event IN ('approved', 'changes_requested', 'merged')"""
    ).fetchone()

    # PR status counts
    statuses = conn.execute("SELECT status, COUNT(*) as n FROM prs GROUP BY status").fetchall()
    status_map = {r["status"]: r["n"] for r in statuses}

    # Approval rate (24h)
    verdicts = conn.execute(
        """SELECT COUNT(*) as total,
            SUM(CASE WHEN status IN ('merged', 'approved') THEN 1 ELSE 0 END) as passed
        FROM prs WHERE last_attempt > datetime('now', '-24 hours')"""
    ).fetchone()
    total = verdicts["total"] or 0
    passed = verdicts["passed"] or 0
    approval_rate = round(passed / total, 3) if total > 0 else None

    # Evaluated in 24h
    evaluated = conn.execute(
        """SELECT COUNT(*) as n FROM prs
           WHERE last_attempt > datetime('now', '-24 hours')
             AND domain_verdict != 'pending'"""
    ).fetchone()

    # Fix success rate
    fix_stats = conn.execute(
        """SELECT COUNT(*) as attempted,
            SUM(CASE WHEN status IN ('merged', 'approved') THEN 1 ELSE 0 END) as succeeded
        FROM prs WHERE fix_attempts > 0"""
    ).fetchone()
    fix_rate = round((fix_stats["succeeded"] or 0) / fix_stats["attempted"], 3) if fix_stats["attempted"] else None

    # Rejection reasons (24h)
    issue_rows = conn.execute(
        """SELECT eval_issues FROM prs
           WHERE eval_issues IS NOT NULL AND eval_issues != '[]'
             AND last_attempt > datetime('now', '-24 hours')"""
    ).fetchall()
    tag_counts = {}
    for row in issue_rows:
        try:
            tags = json.loads(row["eval_issues"])
            for tag in tags:
                if isinstance(tag, str):
                    tag_counts[tag] = tag_counts.get(tag, 0) + 1
        except (json.JSONDecodeError, TypeError):
            pass

    # Source origin counts (24h) — agent vs human vs scraper
    source_origins = _count_source_origins(conn)

    snapshot = {
        "throughput_1h": throughput["n"] if throughput else 0,
        "approval_rate": approval_rate,
        "open_prs": status_map.get("open", 0),
        "merged_total": status_map.get("merged", 0),
        "closed_total": status_map.get("closed", 0),
        "conflict_total": status_map.get("conflict", 0),
        "evaluated_24h": evaluated["n"] if evaluated else 0,
        "fix_success_rate": fix_rate,
        "rejection_broken_wiki_links": tag_counts.get("broken_wiki_links", 0),
        "rejection_frontmatter_schema": tag_counts.get("frontmatter_schema", 0),
        "rejection_near_duplicate": tag_counts.get("near_duplicate", 0),
        "rejection_confidence": tag_counts.get("confidence_miscalibration", 0),
        "rejection_other": sum(v for k, v in tag_counts.items()
                               if k not in ("broken_wiki_links", "frontmatter_schema",
                                            "near_duplicate", "confidence_miscalibration")),
        "extraction_model": config.EXTRACT_MODEL,
        "eval_domain_model": config.EVAL_DOMAIN_MODEL,
        "eval_leo_model": config.EVAL_LEO_STANDARD_MODEL,
        "prompt_version": config.PROMPT_VERSION,
        "pipeline_version": config.PIPELINE_VERSION,
        "source_origin_agent": source_origins.get("agent", 0),
        "source_origin_human": source_origins.get("human", 0),
        "source_origin_scraper": source_origins.get("scraper", 0),
    }

    # Write to DB
    conn.execute(
        """INSERT INTO metrics_snapshots (
            throughput_1h, approval_rate, open_prs, merged_total, closed_total,
            conflict_total, evaluated_24h, fix_success_rate,
            rejection_broken_wiki_links, rejection_frontmatter_schema,
            rejection_near_duplicate, rejection_confidence, rejection_other,
            extraction_model, eval_domain_model, eval_leo_model,
            prompt_version, pipeline_version,
            source_origin_agent, source_origin_human, source_origin_scraper
        ) VALUES (
            :throughput_1h, :approval_rate, :open_prs, :merged_total, :closed_total,
            :conflict_total, :evaluated_24h, :fix_success_rate,
            :rejection_broken_wiki_links, :rejection_frontmatter_schema,
            :rejection_near_duplicate, :rejection_confidence, :rejection_other,
            :extraction_model, :eval_domain_model, :eval_leo_model,
            :prompt_version, :pipeline_version,
            :source_origin_agent, :source_origin_human, :source_origin_scraper
        )""",
        snapshot,
    )

    logger.debug("Recorded metrics snapshot: approval=%.1f%%, throughput=%d/h",
                 (approval_rate or 0) * 100, snapshot["throughput_1h"])

    return snapshot


def _count_source_origins(conn) -> dict[str, int]:
    """Count source origins from recent PRs. Returns {agent: N, human: N, scraper: N}."""
    counts = {"agent": 0, "human": 0, "scraper": 0}

    rows = conn.execute(
        """SELECT origin, COUNT(*) as n FROM prs
           WHERE created_at > datetime('now', '-24 hours')
           GROUP BY origin"""
    ).fetchall()

    for row in rows:
        origin = row["origin"] or "pipeline"
        if origin == "human":
            counts["human"] += row["n"]
        elif origin == "pipeline":
            counts["agent"] += row["n"]
        else:
            counts["scraper"] += row["n"]

    return counts


# ─── Chart data endpoints ─────────────────────────────────────────────────


def get_snapshot_history(conn, days: int = 7) -> list[dict]:
    """Get snapshot history for charting. Returns list of snapshot dicts."""
    rows = conn.execute(
        """SELECT * FROM metrics_snapshots
           WHERE ts > datetime('now', ? || ' days')
           ORDER BY ts ASC""",
        (f"-{days}",),
    ).fetchall()

    return [dict(row) for row in rows]


def get_version_changes(conn, days: int = 30) -> list[dict]:
    """Get points where prompt_version or pipeline_version changed.

    Used for chart annotations — vertical lines marking deployments.
    """
    rows = conn.execute(
        """SELECT ts, prompt_version, pipeline_version
           FROM metrics_snapshots
           WHERE ts > datetime('now', ? || ' days')
           ORDER BY ts ASC""",
        (f"-{days}",),
    ).fetchall()

    changes = []
    prev_prompt = None
    prev_pipeline = None

    for row in rows:
        if row["prompt_version"] != prev_prompt and prev_prompt is not None:
            changes.append({
                "ts": row["ts"],
                "type": "prompt",
                "from": prev_prompt,
                "to": row["prompt_version"],
            })
        if row["pipeline_version"] != prev_pipeline and prev_pipeline is not None:
            changes.append({
                "ts": row["ts"],
                "type": "pipeline",
                "from": prev_pipeline,
                "to": row["pipeline_version"],
            })
        prev_prompt = row["prompt_version"]
        prev_pipeline = row["pipeline_version"]

    return changes