"""Combined speed + quality report (markdown + json side-cars)."""

from __future__ import annotations

import datetime as dt
import json
import os
from typing import Any

from .config import DEFAULT_SYSTEMS


def _fmt(x: float, nd: int = 1) -> str:
    if x is None or x < 0:
        return "—"
    return f"{x:.{nd}f}"


def _speed_table(rows: list[dict[str, Any]]) -> str:
    if not rows:
        return "_(no speed results)_\n"

    # scenarios in stable order
    scenarios: list[str] = []
    for r in rows:
        if r["scenario"] not in scenarios:
            scenarios.append(r["scenario"])
    systems: list[str] = []
    for r in rows:
        if r["system"] not in systems:
            systems.append(r["system"])

    by = {(r["system"], r["scenario"]): r for r in rows}
    out = []
    out.append("| scenario | metric | " + " | ".join(systems) + " | speedup (xserv ÷ llama.cpp) |")
    out.append("|---|---|" + "|".join(["---"] * (len(systems) + 1)) + "|")

    metrics = [
        ("ttft_ms_p50", "TTFT p50 (ms)", "lower"),
        ("ttft_ms_p95", "TTFT p95 (ms)", "lower"),
        ("tpot_ms_p50", "TPOT p50 (ms/tok)", "lower"),
        ("throughput_tok_s", "Throughput (tok/s)", "higher"),
    ]
    for sc in scenarios:
        for key, label, direction in metrics:
            cells = []
            vals = {}
            for s in systems:
                row = by.get((s, sc))
                v = row[key] if row else -1.0
                vals[s] = v
                cells.append(_fmt(v, 2 if "tpot" in key else 1))
            x = vals.get("xserv", -1.0)
            l = vals.get("llama.cpp", -1.0)
            if x > 0 and l > 0:
                ratio = (x / l) if direction == "higher" else (l / x)
                cells.append(f"{ratio:.2f}×")
            else:
                cells.append("—")
            out.append(f"| {sc} | {label} | " + " | ".join(cells) + " |")
    return "\n".join(out) + "\n"


def _quality_table(rows: list[dict[str, Any]]) -> str:
    if not rows:
        return "_(no quality results)_\n"
    by_task: dict[str, list[dict[str, Any]]] = {}
    for r in rows:
        by_task.setdefault(r["task"], []).append(r)
    out: list[str] = []
    out.append("| task | system | n | correct | accuracy | mean tokens | TTFT (ms) | TPOT (ms/tok) | wall (s) |")
    out.append("|---|---|---|---|---|---|---|---|---|")
    for task, task_rows in by_task.items():
        for r in task_rows:
            out.append(
                f"| {task} | {r['system']} | {r['n_total']} | {r['n_correct']} | "
                f"{r['accuracy'] * 100:.1f}% | {r['mean_completion_tokens']:.0f} | "
                f"{_fmt(r['mean_ttft_ms'])} | {_fmt(r['mean_tpot_ms'], 2)} | {r['wall_s']:.1f} |"
            )
    return "\n".join(out) + "\n"


def write_report(
    out_dir: str,
    speed_rows: list[dict[str, Any]],
    speed_raw: list[dict[str, Any]],
    quality_rows: list[dict[str, Any]],
    quality_cases: list[dict[str, Any]],
    env: dict[str, Any],
) -> str:
    os.makedirs(out_dir, exist_ok=True)
    stamp = dt.datetime.now().strftime("%Y%m%d-%H%M%S")
    md_path = os.path.join(out_dir, f"comparison-{stamp}.md")
    json_path = os.path.join(out_dir, f"comparison-{stamp}.json")

    with open(json_path, "w") as f:
        json.dump({
            "stamp": stamp,
            "env": env,
            "speed": {"summary": speed_rows, "raw": speed_raw},
            "quality": {"summary": quality_rows, "cases": quality_cases},
        }, f, indent=2)

    lines: list[str] = []
    lines.append(f"# xserv vs llama.cpp — comparison\n")
    lines.append(f"_Generated: {stamp}_\n")
    lines.append("## Environment\n")
    for k, v in env.items():
        lines.append(f"- **{k}**: {v}")
    lines.append("")
    lines.append("## Speed\n")
    lines.append(_speed_table(speed_rows))
    lines.append("\n## Quality\n")
    lines.append(_quality_table(quality_rows))
    lines.append(f"\n_Raw results: `{os.path.basename(json_path)}`_\n")

    with open(md_path, "w") as f:
        f.write("\n".join(lines))

    print(f"\n[report] wrote {md_path}")
    print(f"[report] wrote {json_path}")
    return md_path