"""FYN-LLM quality assurance toolkit.

Subcommands:
  fitness   — Run LLM fitness tests across four categories
  score     — Score a Stage 5 technique page across 5 quality dimensions
  optimize  — Automated prompt optimization loop with leaderboard output

Run with: python -m pipeline.quality <command>
"""
from __future__ import annotations

import argparse
import json
import sys
from datetime import datetime, timezone
from pathlib import Path

from config import get_settings
from pipeline.llm_client import LLMClient

from .chat_eval import ChatEvalRunner
from .chat_scorer import ChatScoreRunner
from .fitness import FitnessRunner
from .optimizer import OptimizationLoop, OptimizationResult
from .scorer import DIMENSIONS, STAGE_CONFIGS, ScoreRunner


# ── Reporting helpers ────────────────────────────────────────────────────────


def print_leaderboard(result: OptimizationResult, stage: int = 5) -> None:
    """Print a formatted leaderboard of top 5 variants by composite score."""
    dims = STAGE_CONFIGS[stage].dimensions if stage in STAGE_CONFIGS else DIMENSIONS

    # Filter to entries that actually scored (no errors)
    scored = [h for h in result.history if not h.get("error")]
    if not scored:
        print("\n  No successfully scored variants to rank.\n")
        return

    ranked = sorted(scored, key=lambda h: h["composite"], reverse=True)[:5]

    print(f"\n{'='*72}")
    print(f"  LEADERBOARD — Top 5 Variants by Composite Score (Stage {stage})")
    print(f"{'='*72}")

    # Header
    dim_headers = "  ".join(f"{d[:5]:>5s}" for d in dims)
    sep_segments = "  ".join("─" * 5 for _ in dims)
    print(f"  {'#':>2s}  {'Label':<16s}  {'Comp':>5s}  {dim_headers}")
    print(f"  {'─'*2}  {'─'*16}  {'─'*5}  {sep_segments}")

    for i, entry in enumerate(ranked, 1):
        label = entry.get("label", "?")[:16]
        comp = entry["composite"]
        dim_vals = "  ".join(
            f"{entry['scores'].get(d, 0.0):5.2f}" for d in dims
        )
        bar = "█" * int(comp * 20) + "░" * (20 - int(comp * 20))
        print(f"  {i:>2d}  {label:<16s}  {comp:5.3f}  {dim_vals}  {bar}")

    print(f"{'='*72}\n")


def print_trajectory(result: OptimizationResult) -> None:
    """Print an ASCII chart of composite score across iterations."""
    scored = [h for h in result.history if not h.get("error")]
    if len(scored) < 2:
        print("  (Not enough data points for trajectory chart)\n")
        return

    # Get the best composite per iteration
    iter_best: dict[int, float] = {}
    for h in scored:
        it = h["iteration"]
        if it not in iter_best or h["composite"] > iter_best[it]:
            iter_best[it] = h["composite"]

    iterations = sorted(iter_best.keys())
    values = [iter_best[it] for it in iterations]

    # Chart dimensions
    chart_height = 15
    min_val = max(0.0, min(values) - 0.05)
    max_val = min(1.0, max(values) + 0.05)
    val_range = max_val - min_val
    if val_range < 0.01:
        val_range = 0.1
        min_val = max(0.0, values[0] - 0.05)
        max_val = min_val + val_range

    print(f"  {'─'*50}")
    print("  SCORE TRAJECTORY — Best Composite per Iteration")
    print(f"  {'─'*50}")
    print()

    # Render rows top to bottom
    for row in range(chart_height, -1, -1):
        threshold = min_val + (row / chart_height) * val_range
        # Y-axis label every 5 rows
        if row % 5 == 0:
            label = f"{threshold:.2f}"
        else:
            label = "     "
        line = f"  {label} │"

        for vi, val in enumerate(values):
            normalized = (val - min_val) / val_range
            filled_rows = int(normalized * chart_height)
            if filled_rows >= row:
                line += " ● "
            else:
                line += " · "

        print(line)

    # X-axis
    print(f"  ───── ┼{'───' * len(values)}")
    x_labels = "  " + "      "
    for it in iterations:
        x_labels += f"{it:>2d} "
    print(x_labels)
    print("        " + "  iteration →")
    print()


def write_results_json(
    result: OptimizationResult,
    output_dir: str,
    stage: int,
    iterations: int,
    variants_per_iter: int,
    fixture_path: str,
) -> str:
    """Write optimization results to a timestamped JSON file. Returns the path."""
    out_path = Path(output_dir)
    out_path.mkdir(parents=True, exist_ok=True)

    timestamp = datetime.now(timezone.utc).strftime("%Y%m%d_%H%M%S")
    filename = f"optimize_stage{stage}_{timestamp}.json"
    filepath = out_path / filename

    dims = STAGE_CONFIGS[stage].dimensions if stage in STAGE_CONFIGS else DIMENSIONS

    payload = {
        "config": {
            "stage": stage,
            "iterations": iterations,
            "variants_per_iter": variants_per_iter,
            "fixture_path": fixture_path,
        },
        "best_prompt": result.best_prompt,
        "best_scores": {
            "composite": result.best_score.composite,
            **{d: result.best_score.scores.get(d, 0.0) for d in dims},
        },
        "elapsed_seconds": result.elapsed_seconds,
        "history": result.history,
    }

    filepath.write_text(json.dumps(payload, indent=2), encoding="utf-8")
    return str(filepath)


# ── CLI ──────────────────────────────────────────────────────────────────────


def main() -> int:
    parser = argparse.ArgumentParser(
        prog="pipeline.quality",
        description="FYN-LLM quality assurance toolkit",
    )
    sub = parser.add_subparsers(dest="command")

    # -- fitness subcommand --
    sub.add_parser("fitness", help="Run LLM fitness tests across four categories")

    # -- score subcommand --
    score_parser = sub.add_parser(
        "score",
        help="Score a Stage 5 technique page across 5 quality dimensions",
    )
    source_group = score_parser.add_mutually_exclusive_group(required=True)
    source_group.add_argument(
        "--file",
        type=str,
        help="Path to a moments JSON file (creator_name, moments array)",
    )
    source_group.add_argument(
        "--slug",
        type=str,
        help="Technique slug to load from the database",
    )
    score_parser.add_argument(
        "--voice-level",
        type=float,
        default=None,
        help="Voice preservation dial (0.0=clinical, 1.0=maximum voice). Triggers re-synthesis before scoring.",
    )

    # -- optimize subcommand --
    opt_parser = sub.add_parser(
        "optimize",
        help="Automated prompt optimization loop with leaderboard output",
    )

    # -- apply subcommand --
    apply_parser = sub.add_parser(
        "apply",
        help="Apply a winning prompt from optimization results to the stage's prompt file",
    )
    apply_parser.add_argument(
        "results_file",
        type=str,
        help="Path to an optimization results JSON file",
    )
    apply_parser.add_argument(
        "--dry-run",
        action="store_true",
        default=False,
        help="Show what would change without writing",
    )
    opt_parser.add_argument(
        "--stage",
        type=int,
        default=5,
        help="Pipeline stage to optimize (default: 5)",
    )
    opt_parser.add_argument(
        "--iterations",
        type=int,
        default=10,
        help="Number of optimization iterations (default: 10)",
    )
    opt_parser.add_argument(
        "--variants-per-iter",
        type=int,
        default=2,
        help="Variants generated per iteration (default: 2)",
    )
    opt_source = opt_parser.add_mutually_exclusive_group(required=True)
    opt_source.add_argument(
        "--file",
        type=str,
        help="Path to moments JSON fixture file",
    )
    opt_source.add_argument(
        "--video-id",
        type=str,
        help="Video UUID — exports fixture from DB automatically (requires DATABASE_URL, REDIS_URL)",
    )
    opt_parser.add_argument(
        "--output-dir",
        type=str,
        default="backend/pipeline/quality/results/",
        help="Directory to write result JSON (default: backend/pipeline/quality/results/)",
    )
    opt_parser.add_argument(
        "--apply",
        action="store_true",
        default=False,
        help="Write the winning prompt back to the stage's prompt file (backs up the original first)",
    )

    # -- chat_eval subcommand --
    chat_parser = sub.add_parser(
        "chat_eval",
        help="Evaluate chat quality across a test suite of queries",
    )
    chat_parser.add_argument(
        "--suite",
        type=str,
        required=True,
        help="Path to a chat test suite YAML/JSON file",
    )
    chat_parser.add_argument(
        "--base-url",
        type=str,
        default="http://localhost:8096",
        help="Chat API base URL (default: http://localhost:8096)",
    )
    chat_parser.add_argument(
        "--output",
        type=str,
        default="backend/pipeline/quality/results/",
        help="Output path for results JSON (default: backend/pipeline/quality/results/)",
    )
    chat_parser.add_argument(
        "--timeout",
        type=float,
        default=120.0,
        help="Request timeout in seconds (default: 120)",
    )

    args = parser.parse_args()

    if args.command is None:
        parser.print_help()
        return 1

    if args.command == "fitness":
        settings = get_settings()
        client = LLMClient(settings)
        runner = FitnessRunner(client)
        return runner.run_all()

    if args.command == "score":
        return _run_score(args)

    if args.command == "optimize":
        return _run_optimize(args)

    if args.command == "apply":
        return _run_apply(args)

    if args.command == "chat_eval":
        return _run_chat_eval(args)

    return 0


def _run_score(args: argparse.Namespace) -> int:
    """Execute the score subcommand."""
    # -- Load source data --
    if args.slug:
        print("DB loading not yet implemented", file=sys.stderr)
        return 1

    try:
        with open(args.file) as f:
            data = json.load(f)
    except FileNotFoundError:
        print(f"File not found: {args.file}", file=sys.stderr)
        return 1
    except json.JSONDecodeError as exc:
        print(f"Invalid JSON in {args.file}: {exc}", file=sys.stderr)
        return 1

    moments = data.get("moments", [])
    creator_name = data.get("creator_name", "Unknown")

    if not moments:
        print("No moments found in input file", file=sys.stderr)
        return 1

    settings = get_settings()
    client = LLMClient(settings)
    runner = ScoreRunner(client)

    # -- Voice-level mode: re-synthesize then score --
    if args.voice_level is not None:
        voice_level = args.voice_level
        if not (0.0 <= voice_level <= 1.0):
            print("--voice-level must be between 0.0 and 1.0", file=sys.stderr)
            return 1

        print(f"\nRe-synthesizing + scoring for '{creator_name}' ({len(moments)} moments, voice_level={voice_level})...")
        result = runner.synthesize_and_score(moments, creator_name, voice_level)

        if result.error:
            runner.print_report(result)
            return 1

        runner.print_report(result)
        return 0

    # -- Standard mode: build page stub from moments, score directly --
    page_json = {
        "title": f"{creator_name} — Technique Page",
        "creator_name": creator_name,
        "summary": f"Technique page synthesized from {len(moments)} key moments.",
        "body_sections": [
            {
                "heading": m.get("topic_tags", ["Technique"])[0] if m.get("topic_tags") else "Technique",
                "content": m.get("summary", "") + "\n\n" + m.get("transcript_excerpt", ""),
            }
            for m in moments
        ],
    }

    print(f"\nScoring page for '{creator_name}' ({len(moments)} moments)...")

    result = runner.score_page(page_json, moments)

    if result.error:
        runner.print_report(result)
        return 1

    runner.print_report(result)
    return 0


def _run_optimize(args: argparse.Namespace) -> int:
    """Execute the optimize subcommand."""
    # Stage validation — stages 2-5 are supported
    if args.stage not in STAGE_CONFIGS:
        print(
            f"Error: unsupported stage {args.stage}. Valid stages: {sorted(STAGE_CONFIGS)}",
            file=sys.stderr,
        )
        return 1

    # Resolve fixture: either from --file or auto-export from --video-id
    fixture_path: str
    if args.file:
        fixture_path = args.file
    else:
        # Auto-export from database
        print(f"\n[OPTIMIZE] Exporting fixture from video_id={args.video_id}...", file=sys.stderr)
        import tempfile
        from pipeline.export_fixture import export_fixture

        settings = get_settings()
        tmp = tempfile.NamedTemporaryFile(suffix=".json", prefix="optimize_fixture_", delete=False)
        tmp.close()
        exit_code = export_fixture(
            database_url=settings.database_url,
            redis_url=settings.redis_url,
            video_id=args.video_id,
            output_path=tmp.name,
        )
        if exit_code != 0:
            print(f"Error: fixture export failed (exit code {exit_code})", file=sys.stderr)
            return 1
        fixture_path = tmp.name
        print(f"[OPTIMIZE] Fixture exported to: {fixture_path}", file=sys.stderr)

    fixture = Path(fixture_path)
    if not fixture.exists():
        print(f"Error: fixture file not found: {fixture_path}", file=sys.stderr)
        return 1

    # Ensure output dir
    Path(args.output_dir).mkdir(parents=True, exist_ok=True)

    settings = get_settings()
    client = LLMClient(settings)

    loop = OptimizationLoop(
        client=client,
        stage=args.stage,
        fixture_path=fixture_path,
        iterations=args.iterations,
        variants_per_iter=args.variants_per_iter,
        output_dir=args.output_dir,
    )

    try:
        result = loop.run()
    except KeyboardInterrupt:
        print("\n  Optimization interrupted by user.", file=sys.stderr)
        return 130
    except Exception as exc:
        print(f"\nError: optimization failed: {exc}", file=sys.stderr)
        return 1

    # If the loop returned an error on baseline, report and exit
    if result.best_score.error and not result.history:
        print(f"\nError: {result.best_score.error}", file=sys.stderr)
        return 1

    # Reporting
    print_leaderboard(result, stage=args.stage)
    print_trajectory(result)

    # Write results JSON
    try:
        json_path = write_results_json(
            result=result,
            output_dir=args.output_dir,
            stage=args.stage,
            iterations=args.iterations,
            variants_per_iter=args.variants_per_iter,
            fixture_path=fixture_path,
        )
        print(f"  Results written to: {json_path}")
    except OSError as exc:
        print(f"  Warning: failed to write results JSON: {exc}", file=sys.stderr)

    # Apply winning prompt if requested
    if args.apply:
        baseline_composite = 0.0
        for h in result.history:
            if h.get("label") == "baseline" and not h.get("error"):
                baseline_composite = h["composite"]
                break

        if result.best_score.composite <= baseline_composite:
            print("\n  --apply: Best prompt did not beat baseline — skipping apply.")
        elif result.best_score.error:
            print("\n  --apply: Best result has an error — skipping apply.")
        else:
            print("\n  --apply: Winning prompt beat baseline — applying...")
            success, msg = apply_prompt(args.stage, result.best_prompt)
            print(f"  {msg}")
            if not success:
                return 1

    return 0


def apply_prompt(stage: int, new_prompt: str, dry_run: bool = False) -> tuple[bool, str]:
    """Apply a new prompt to a stage's prompt file. Returns (success, message).

    Creates a timestamped backup of the original before overwriting.
    """
    if stage not in STAGE_CONFIGS:
        return False, f"Unsupported stage {stage}. Valid: {sorted(STAGE_CONFIGS)}"

    config = STAGE_CONFIGS[stage]
    settings = get_settings()
    prompt_path = Path(settings.prompts_path) / config.prompt_file

    if not prompt_path.exists():
        return False, f"Prompt file not found: {prompt_path}"

    original = prompt_path.read_text(encoding="utf-8")

    if original.strip() == new_prompt.strip():
        return True, "No change — winning prompt is identical to current prompt."

    # Show diff summary
    orig_lines = original.strip().splitlines()
    new_lines = new_prompt.strip().splitlines()
    print(f"\n  Prompt file: {prompt_path}")
    print(f"  Original: {len(orig_lines)} lines, {len(original)} chars")
    print(f"  New:      {len(new_lines)} lines, {len(new_prompt)} chars")

    # Simple line-level diff summary
    import difflib
    diff = list(difflib.unified_diff(orig_lines, new_lines, lineterm="", n=2))
    added = sum(1 for l in diff if l.startswith("+") and not l.startswith("+++"))
    removed = sum(1 for l in diff if l.startswith("-") and not l.startswith("---"))
    print(f"  Changes:  +{added} lines, -{removed} lines")

    if dry_run:
        print("\n  [DRY RUN] Would write to:", prompt_path)
        if len(diff) <= 40:
            print()
            for line in diff:
                print(f"  {line}")
        else:
            print(f"\n  (diff is {len(diff)} lines — showing first 30)")
            for line in diff[:30]:
                print(f"  {line}")
            print("  ...")
        return True, "Dry run — no files modified."

    # Backup original
    timestamp = datetime.now(timezone.utc).strftime("%Y%m%d_%H%M%S")
    backup_path = prompt_path.with_suffix(f".{timestamp}.bak")
    backup_path.write_text(original, encoding="utf-8")
    print(f"  Backup:   {backup_path}")

    # Write new prompt
    prompt_path.write_text(new_prompt, encoding="utf-8")
    print(f"  ✓ Written: {prompt_path}")

    return True, f"Prompt applied. Backup at {backup_path}"


def _run_apply(args: argparse.Namespace) -> int:
    """Execute the apply subcommand — read a results JSON and apply the winning prompt."""
    results_path = Path(args.results_file)
    if not results_path.exists():
        print(f"Error: results file not found: {args.results_file}", file=sys.stderr)
        return 1

    try:
        data = json.loads(results_path.read_text(encoding="utf-8"))
    except json.JSONDecodeError as exc:
        print(f"Error: invalid JSON in {args.results_file}: {exc}", file=sys.stderr)
        return 1

    stage = data.get("config", {}).get("stage")
    best_prompt = data.get("best_prompt", "")
    best_scores = data.get("best_scores", {})

    if not stage:
        print("Error: results JSON missing config.stage", file=sys.stderr)
        return 1
    if not best_prompt:
        print("Error: results JSON missing best_prompt or it's empty", file=sys.stderr)
        return 1

    composite = best_scores.get("composite", 0)
    print(f"\n  Applying results from: {results_path}")
    print(f"  Stage: {stage}")
    print(f"  Best composite score: {composite:.3f}")

    success, msg = apply_prompt(stage, best_prompt, dry_run=args.dry_run)
    print(f"\n  {msg}")
    return 0 if success else 1


def _run_chat_eval(args: argparse.Namespace) -> int:
    """Execute the chat_eval subcommand — evaluate chat quality across a test suite."""
    suite_path = Path(args.suite)
    if not suite_path.exists():
        print(f"Error: suite file not found: {args.suite}", file=sys.stderr)
        return 1

    # Load test cases
    try:
        cases = ChatEvalRunner.load_suite(suite_path)
    except Exception as exc:
        print(f"Error loading test suite: {exc}", file=sys.stderr)
        return 1

    if not cases:
        print("Error: test suite contains no queries", file=sys.stderr)
        return 1

    print(f"\n  Chat Evaluation: {len(cases)} queries from {suite_path}")
    print(f"  Endpoint: {args.base_url}")

    # Build scorer and runner
    settings = get_settings()
    client = LLMClient(settings)
    scorer = ChatScoreRunner(client)
    runner = ChatEvalRunner(
        scorer=scorer,
        base_url=args.base_url,
        timeout=args.timeout,
    )

    # Execute
    results = runner.run_suite(cases)

    # Print summary
    runner.print_summary(results)

    # Write results
    try:
        json_path = runner.write_results(results, args.output)
        print(f"  Results written to: {json_path}")
    except OSError as exc:
        print(f"  Warning: failed to write results: {exc}", file=sys.stderr)

    # Exit code: 0 if at least one scored, 1 if all errored
    scored = [r for r in results if r.score and not r.score.error and not r.request_error]
    return 0 if scored else 1


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