"""Generates Markdown report from raw benchmark rows."""
import statistics
from collections import defaultdict


def summarise(values: list[float]) -> dict:
    if not values:
        return {"avg": 0, "median": 0, "stdev": 0, "min": 0, "max": 0}
    return {
        "avg":    round(statistics.mean(values), 2),
        "median": round(statistics.median(values), 2),
        "stdev":  round(statistics.stdev(values), 2) if len(values) > 1 else 0.0,
        "min":    round(min(values), 2),
        "max":    round(max(values), 2),
    }


def build_markdown(rows: list[dict], ts: str) -> str:
    # Group by (scenario, framework)
    data: dict[str, dict[str, list[float]]] = defaultdict(lambda: defaultdict(list))
    scenario_labels: dict[str, str] = {}
    frameworks: list[str] = []

    for row in rows:
        sk = row["scenario_key"]
        sl = row["scenario"]
        fw = row["framework"]
        scenario_labels[sk] = sl
        if fw not in frameworks:
            frameworks.append(fw)
        data[sk][fw].append(row["ms"])

    lines = []
    lines.append(f"# Benchmark Results\n")
    lines.append(f"Generated: {ts}\n")
    lines.append(f"Frameworks: {' vs '.join(frameworks)}\n")

    COMMON = ["add_alert", "delete_alert", "search_filter"]
    EDGE   = ["large_list_add", "rapid_fire", "empty_search"]

    for section, keys in [("Common scenarios", COMMON), ("Edge case scenarios", EDGE)]:
        lines.append(f"\n## {section}\n")

        # Header
        header = "| Scenario |"
        sep    = "| --- |"
        for fw in frameworks:
            header += f" {fw} avg (ms) | {fw} median (ms) | {fw} stdev |"
            sep    += " ---: | ---: | ---: |"
        lines.append(header)
        lines.append(sep)

        for key in keys:
            if key not in data:
                continue
            sl = scenario_labels.get(key, key)
            row_line = f"| {sl} |"
            for fw in frameworks:
                s = summarise(data[key].get(fw, []))
                row_line += f" {s['avg']} | {s['median']} | {s['stdev']} |"
            lines.append(row_line)

    # WebSocket payload table
    lines.append("\n## WebSocket payload (avg bytes per action)\n")
    header = "| Scenario |"
    sep    = "| --- |"
    for fw in frameworks:
        header += f" {fw} sent | {fw} received |"
        sep    += " ---: | ---: |"
    lines.append(header)
    lines.append(sep)

    ws_data: dict[str, dict[str, list]] = defaultdict(lambda: defaultdict(list))
    for row in rows:
        ws_data[row["scenario_key"]][row["framework"] + "_sent"].append(row["ws_sent_b"])
        ws_data[row["scenario_key"]][row["framework"] + "_recv"].append(row["ws_recv_b"])

    for key in COMMON + EDGE:
        if key not in ws_data:
            continue
        sl = scenario_labels.get(key, key)
        row_line = f"| {sl} |"
        for fw in frameworks:
            sent_avg = round(statistics.mean(ws_data[key].get(f"{fw}_sent", [0])), 0)
            recv_avg = round(statistics.mean(ws_data[key].get(f"{fw}_recv", [0])), 0)
            row_line += f" {int(sent_avg)} B | {int(recv_avg)} B |"
        lines.append(row_line)

    lines.append("\n## Notes\n")
    lines.append("- All times are wall-clock milliseconds (action → DOM update).")
    lines.append("- Warmup iterations are discarded.")
    lines.append("- WebSocket bytes measured per interaction via Playwright.")
    lines.append("- Large list scenario pre-loads 500 alerts.")
    lines.append("- Rapid fire: 5 consecutive clicks with 50ms interval.\n")

    return "\n".join(lines)


if __name__ == "__main__":
    import sys, json
    rows = json.load(open(sys.argv[1]))
    print(build_markdown(rows, "manual"))