#!/usr/bin/env python3
"""Suggest candidate questions for the exemplar pool.

Queries vault.db for the highest-quality questions per topic, scored by:
  - Has napkin_math (+3)
  - Has common_mistake (+2)
  - Solution length > 500 chars (+2)
  - Scenario length > 300 chars (+1)

Outputs a ranked list and optionally a shell script of `vault mark-exemplar`
commands. Questions must first have their provenance changed from 'imported'
to 'human' in the YAML file before mark-exemplar will accept them.

Usage:
    python3 interviews/vault-cli/scripts/suggest_exemplars.py \
        --vault-dir interviews/vault \
        --top 3 \
        [--emit-script]
"""

from __future__ import annotations

import argparse
import sqlite3
from collections import defaultdict
from pathlib import Path


def score_question(row: dict) -> int:
    s = 0
    if row.get("napkin_math"):
        s += 3
    if row.get("common_mistake"):
        s += 2
    sol = row.get("realistic_solution") or ""
    if len(sol) > 500:
        s += 2
    scenario = row.get("scenario") or ""
    if len(scenario) > 300:
        s += 1
    return s


def main() -> None:
    parser = argparse.ArgumentParser(description="Suggest exemplar candidates")
    parser.add_argument("--vault-dir", type=Path, default=Path("interviews/vault"))
    parser.add_argument("--top", type=int, default=3, help="Candidates per topic")
    parser.add_argument("--emit-script", action="store_true", help="Print shell commands")
    parser.add_argument("--min-topics", type=int, default=10, help="Cover at least N topics")
    args = parser.parse_args()

    db_path = args.vault_dir / "vault.db"
    if not db_path.exists():
        print(f"error: {db_path} not found. Run `vault build` first.")
        raise SystemExit(1)

    conn = sqlite3.connect(db_path)
    conn.row_factory = sqlite3.Row
    rows = conn.execute(
        "SELECT id, title, topic, track, level, zone, scenario, "
        "common_mistake, realistic_solution, napkin_math, file_path "
        "FROM questions WHERE status = 'published' ORDER BY topic, id"
    ).fetchall()

    # Group by topic and score
    by_topic: dict[str, list[dict]] = defaultdict(list)
    for r in rows:
        d = dict(r)
        d["score"] = score_question(d)
        by_topic[d["topic"]].append(d)

    # Sort each topic by score descending
    for topic in by_topic:
        by_topic[topic].sort(key=lambda x: x["score"], reverse=True)

    # Select top N per topic
    selected: list[dict] = []
    for topic in sorted(by_topic.keys()):
        candidates = by_topic[topic][: args.top]
        selected.extend(candidates)

    # Print summary
    topics_covered = len(set(q["topic"] for q in selected))
    print(f"Selected {len(selected)} candidates across {topics_covered} topics\n")

    if args.emit_script:
        print("#!/bin/bash")
        print("# Run after changing provenance to 'human' in each YAML file")
        print(f"# Generated by suggest_exemplars.py --top {args.top}\n")
        for q in selected:
            print(f"# [{q['topic']}] {q['title'][:60]} (score={q['score']})")
            print(f"vault mark-exemplar {q['id']} --vault-dir {args.vault_dir}")
            print()
    else:
        # Print table
        current_topic = None
        for q in selected:
            if q["topic"] != current_topic:
                current_topic = q["topic"]
                print(f"\n── {current_topic} ──")
            print(
                f"  [{q['score']}] {q['id']}"
                f"  {q['level']}/{q['zone']}/{q['track']}"
                f"  {q['title'][:70]}"
            )

    print(f"\nTotal: {len(selected)} candidates, {topics_covered} topics")
    print(
        "\nNext steps:"
        "\n  1. Change provenance: imported → human in each YAML"
        "\n  2. Run: vault mark-exemplar <id> --vault-dir interviews/vault"
        "\n  3. Run: vault build --local-json --vault-dir interviews/vault"
    )


if __name__ == "__main__":
    main()