eval/score_generation.py

"""Score one generation task: Content Faithfulness (CF), Instruction Following (IF), Aesthetic Quality (AQ).

Run `run_ocr.py` first. Predictions are read from <pred_dir>/<task>/<id>.png.

    python eval/score_generation.py --task multi_image --pred_dir outputs/my_model --workers 16

CF   text: GPT-4.1 extracts the slide text the instruction requires; OCR lines
           are re-joined against those strings; each required string is matched
           to its closest OCR line by Levenshtein distance;
           S_text = max(10 - 9 * sum(dist) / sum(len), 1).
     multi_image adds an input-image preservation score (judge `overall_score`)
           and CF = (S_text + S_image) / 2.
IF   unweighted mean of six sub-dimensions (text or style_json prompt;
     template cases also show the reference slide).
AQ   unweighted mean of four sub-dimensions, judged from the output image only.
"""

import argparse
import json
import os
import re
from concurrent.futures import ThreadPoolExecutor
from itertools import combinations
from pathlib import Path

from rapidfuzz import fuzz

from common import (bench_path, chat, get_client, image_part, load_jsonl, load_prompt, mean,
                    subdimension_mean, text_part, write_jsonl)

EXTRACT_PROMPT = (
    "From the following PPT instruction, extract ALL text strings that are explicitly written out and are required "
    "to appear on the PPT page. This includes any quoted text, statements, captions, labels, or any other text that "
    "is directly specified in the instruction as content to be displayed on the slide. DO NOT infer or generate new "
    "text. Only extract what is explicitly present in the instruction and is required to be shown on the PPT. "
    "Return ONLY a JSON array (Python list) of strings, each string is a text to be displayed. Do not output "
    "anything except the JSON array."
)


# ----------------------------------------------------------------- CF (text)
def levenshtein(a, b):
    if a == b:
        return 0
    if not a or not b:
        return len(a) or len(b)
    prev = list(range(len(b) + 1))
    for i, ca in enumerate(a, 1):
        cur = [i]
        for j, cb in enumerate(b, 1):
            cur.append(min(cur[j - 1] + 1, prev[j] + 1, prev[j - 1] + (ca != cb)))
        prev = cur
    return prev[-1]


def _norm(s):
    return "".join(s.lower().split())


def rejoin_lines(lines, targets, max_extra=3):
    """Join OCR lines that together spell a required string (RapidFuzz ratio > 90)."""
    target_norms = [_norm(t) for t in targets]
    out, used = [], set()
    for i, line in enumerate(lines):
        if i in used:
            continue
        cur = _norm(line)
        if cur in target_norms:
            out.append(line)
            used.add(i)
            continue
        joined = None
        for tn in target_norms:
            if fuzz.ratio(cur, tn[: len(cur)]) <= 90:
                continue
            for r in range(1, max_extra + 1):
                for combo in combinations(range(i + 1, len(lines)), r):
                    cand = " ".join(lines[k] for k in (i,) + combo)
                    if fuzz.ratio(_norm(cand), tn) > 90:
                        joined = (cand, (i,) + combo)
                        break
                if joined:
                    break
            if joined:
                break
        if joined:
            out.append(joined[0])
            used.update(joined[1])
        else:
            out.append(line)
            used.add(i)
    return out


def text_score(targets, ocr_lines):
    dist = sum(min(levenshtein(t, g) for g in ocr_lines) for t in targets)
    total = sum(len(t) for t in targets)
    return round(max(10 - 9 * dist / total, 1), 2)


def extract_style_json(instruction):
    """Return the JSON block of a style_json instruction (text after '### SLIDE JSON:')."""
    idx = instruction.find("### SLIDE JSON:")
    if idx < 0:
        idx = instruction.find("```json")
    if idx < 0:
        return instruction
    rest = instruction[idx:]
    m = re.search(r"```json\s*\n(.*?)```", rest, re.DOTALL)
    if m:
        return m.group(1).strip()
    s, e = rest.find("{"), rest.rfind("}")
    return rest[s : e + 1] if 0 <= s < e else rest


# ------------------------------------------------------------------- scoring
def score_cf(client, task, case, img, ocr_file):
    targets = chat(client, EXTRACT_PROMPT, case["instruction"], temperature=0.2, max_tokens=800)
    targets = [str(t).strip() for t in targets if str(t).strip()] if isinstance(targets, list) else []
    lines = [l.strip() for l in open(ocr_file, encoding="utf-8")] if os.path.exists(ocr_file) else []
    lines = [l for l in lines if l]
    if not targets or not lines:
        return {"cf_error": "no required text extracted" if not targets else "no OCR text"}
    out = {"cf_text": text_score(targets, rejoin_lines(lines, targets))}
    out["cf"] = out["cf_text"]
    if task == "multi_image":
        content = [text_part("Generated PPT:"), image_part(img), text_part("Sub-Image List (required sub-images):")]
        for k, p in enumerate(case["input_images"], 1):
            content += [text_part(f"Sub-Image {k}:"), image_part(bench_path(p))]
        res = chat(client, load_prompt("content_faithfulness.txt"), content, temperature=0.2, max_tokens=1200)
        out["cf_image"] = float(res["overall_score"])
        out["cf"] = round((out["cf_text"] + out["cf_image"]) / 2, 2)
    return out


def score_if(client, task, case, img):
    is_json = "JSON" in case["instruction"]
    if is_json:
        content = [text_part(f"## Style JSON Specification\n\n```json\n{extract_style_json(case['instruction'])}\n```\n\n")]
    else:
        content = [text_part(f"## Style Description\n\n{case['instruction']}\n\n")]
    if task == "template":
        content += [
            text_part(
                "## Reference Slide Image (for style only)\n\nThe following image is a reference slide from the same "
                "presentation. Use it only to infer the visual style (palette, typography, background, decorative "
                "motifs, etc.), not for layout or content placement.\n"
            ),
            image_part(bench_path(case["input_images"][0])),
        ]
    content += [
        text_part("## Generated Slide Image\n\nThe image below is the AI-generated slide. Evaluate how well it follows the style instructions above."),
        image_part(img),
    ]
    prompt = "style_instruction_following_json.txt" if is_json else "style_instruction_following_text.txt"
    return {"if": subdimension_mean(chat(client, load_prompt(prompt), content, temperature=0.2, max_tokens=2000))}


def score_aq(client, img):
    content = [text_part("## Generated Slide Image\n\nThe image below is the AI-generated slide. Evaluate its aesthetic quality."), image_part(img)]
    return {"aq": subdimension_mean(chat(client, load_prompt("aesthetic_quality.txt"), content, temperature=0.2, max_tokens=2000))}


def score_case(client, task, case, img, ocr_file):
    """Each metric is scored independently; a failure leaves only that metric empty."""
    out = {"id": case["id"], "source": case["source"], "prompt_type": case["prompt_type"]}
    for name, fn in (("cf", lambda: score_cf(client, task, case, img, ocr_file)),
                     ("if", lambda: score_if(client, task, case, img)),
                     ("aq", lambda: score_aq(client, img))):
        try:
            out.update(fn())
        except Exception as e:
            out[f"{name}_error"] = repr(e)
    return out


def main():
    ap = argparse.ArgumentParser()
    ap.add_argument("--task", required=True, choices=["t2i", "template", "multi_image"])
    ap.add_argument("--pred_dir", required=True)
    ap.add_argument("--ocr_dir", default=None, help="Defaults to <pred_dir>/ocr.")
    ap.add_argument("--out", default=None, help="Defaults to <pred_dir>/scores/<task>.jsonl.")
    ap.add_argument("--workers", type=int, default=8)
    args = ap.parse_args()

    client = get_client()
    ocr_dir = Path(args.ocr_dir or os.path.join(args.pred_dir, "ocr")) / args.task
    cases = load_jsonl(bench_path(f"data/{args.task}.jsonl"))

    def run(case):
        img = Path(args.pred_dir) / args.task / f"{case['id']}.png"
        if not img.exists():
            return {"id": case["id"], "error": "missing prediction"}
        return score_case(client, args.task, case, str(img), str(ocr_dir / f"{case['id']}.txt"))

    with ThreadPoolExecutor(args.workers) as ex:
        rows = list(ex.map(run, cases))

    out = args.out or os.path.join(args.pred_dir, "scores", f"{args.task}.jsonl")
    write_jsonl(out, rows)
    summary = {m: mean(r[m] for r in rows if r.get(m) is not None) for m in ("cf", "if", "aq")}
    summary["n_scored"] = {m: sum(r.get(m) is not None for r in rows) for m in ("cf", "if", "aq")}
    print(json.dumps({"task": args.task, **summary}, indent=1))


if __name__ == "__main__":
    main()