"""Precomputed example presets shown in the app so a visitor can try the tool WITHOUT
signing in and WITHOUT running any real HF job.

Each example's output WARC(s) were produced once by ``scripts/build_examples.py`` and
uploaded to a public HF bucket, so the "Download" link is a real, working file URL. The
app streams *simulated* (but realistic) job logs and renders the precomputed estimate and
result — no ``JobRunner`` call, no OAuth token needed.

The record counts / byte sizes / filenames below come from the actual build; update them
whenever the datasets are rebuilt. `n_records` for the capped examples equals `max_records`.
"""
from __future__ import annotations

from dataclasses import dataclass, field
from typing import List

from . import config
from .estimate import Estimate, format_estimate
from .jobs import bucket_file_url, bucket_web_url

# Public bucket that holds the precomputed example outputs (must be public-readable).
EXAMPLES_BUCKET = "malteos/cc-repackage-examples"


@dataclass(frozen=True)
class Example:
    key: str
    title: str
    description: str
    # Form values the button fills in (mirrors the live filter fields).
    sql_where: str = ""
    domains: List[str] = field(default_factory=list)
    hostnames: List[str] = field(default_factory=list)
    languages: List[str] = field(default_factory=list)
    crawls: List[str] = field(default_factory=list)
    name: str = "repackaged"
    max_records: int = 0
    # Precomputed results (from the build) — n_records/total_bytes drive the estimate.
    n_records: int = 0
    total_bytes: int = 0
    # Hosting on the public examples bucket.
    bucket: str = EXAMPLES_BUCKET
    path: str = ""
    files: List[str] = field(default_factory=list)  # e.g. ["commoncrawl-org-001.warc.gz"]
    # Representative count for the "N parquet file(s) to scan" log line (from the build).
    scan_files: int = 300

    def download_urls(self) -> List[tuple]:
        """(filename, resolve-url) for each produced WARC — real, direct downloads."""
        return [(f, bucket_file_url(self.bucket, self.path, f)) for f in self.files]

    def folder_url(self) -> str:
        return bucket_web_url(self.bucket, self.path)


# The "from build" values below were produced by scripts/build_examples.py and uploaded to
# EXAMPLES_BUCKET; re-run that script and refresh them whenever the datasets are rebuilt.
_CRAWL = "CC-MAIN-2026-21"

EXAMPLES: List[Example] = [
    Example(
        key="commoncrawl-org",
        title="All commoncrawl.org pages",
        description="Every capture of commoncrawl.org in one crawl — uses just the "
                    "Registered domains field, no record cap.",
        domains=["commoncrawl.org"],
        crawls=[_CRAWL],
        name="commoncrawl-org",
        max_records=0,
        n_records=307,        # from build
        total_bytes=2_494_825,  # from build
        path="commoncrawl-org",
        files=["commoncrawl-org-001.warc.gz"],  # from build
        scan_files=300,       # from build
    ),
    Example(
        key="wikipedia-fr",
        title="10 French Wikipedia pages",
        description="French-language pages under wikipedia.org — uses the Registered domains "
                    "+ Content languages fields with a Max records cap (no SQL).",
        domains=["wikipedia.org"],
        languages=["fra"],
        crawls=[_CRAWL],
        name="wikipedia-fr",
        max_records=10,
        n_records=10,
        total_bytes=334_225,  # from build
        path="wikipedia-fr",
        files=["wikipedia-fr-001.warc.gz"],  # from build
        scan_files=300,       # from build
    ),
    Example(
        key="pdfs",
        title="10 PDF documents from one crawl",
        description="The first 10 records the index detected as application/pdf in one crawl.",
        sql_where="content_mime_detected = 'application/pdf'",
        crawls=[_CRAWL],
        name="pdfs",
        max_records=10,
        n_records=10,
        total_bytes=19_857_520,  # from build
        path="pdfs",
        files=["pdfs-001.warc.gz"],  # from build
        scan_files=8,         # from build (capped via --max-files)
    ),
    Example(
        key="homepages",
        title="500 homepages from one crawl",
        description="The first 500 records whose URL path is '/' (site homepages) in one crawl.",
        sql_where="url_path = '/'",
        crawls=[_CRAWL],
        name="homepages",
        max_records=500,
        n_records=500,
        total_bytes=12_263_615,  # from build
        path="homepages",
        files=["homepages-001.warc.gz"],  # from build
        scan_files=4,         # from build (capped via --max-files)
    ),
]

EXAMPLES_BY_KEY = {ex.key: ex for ex in EXAMPLES}


# --- Human-readable helpers --------------------------------------------------

def _fmt_bytes(n: int) -> str:
    step = 1024.0
    val = float(n)
    for unit in ("B", "KiB", "MiB", "GiB", "TiB"):
        if val < step or unit == "TiB":
            return f"{val:.0f} {unit}" if unit == "B" else f"{val:.1f} {unit}"
        val /= step
    return f"{n} B"


# --- Rendered markdown (reuses the real estimate/link builders) --------------

def estimate_markdown(ex: Example) -> str:
    """The same cost-estimate block a real estimate job would produce."""
    return format_estimate(Estimate(ex.n_records, ex.total_bytes, config.DEFAULT_FLAVOR))


def result_markdown(ex: Example) -> str:
    """The 'repackaging complete' panel — with REAL download links to the hosted WARC(s)."""
    downloads = "\n".join(
        f"- **[⬇️ Download `{fname}`]({url})**" for fname, url in ex.download_urls()
    )
    return (
        "### ✅ Repackaging complete\n"
        "🧪 _This is a **precomputed example** — no HF Job ran and no sign-in was needed. "
        "Sign in above to run your own repackaging._\n\n"
        f"**{ex.n_records:,} records · {_fmt_bytes(ex.total_bytes)}** in the public "
        "examples bucket:\n\n"
        f"{downloads}\n\n"
        f"**[📂 Browse the example folder]({ex.folder_url()})**"
    )


# --- Simulated (but realistic) job logs, streamed line-by-line ---------------

def estimate_log_lines(ex: Example) -> List[str]:
    """Mirror src/index_query.py's real estimate-job output (SQL vs structured filter)."""
    limit_note = f" limit={ex.max_records}" if ex.max_records > 0 else ""
    if ex.sql_where:
        filter_line = f"[index] mode=cdn crawls=['{ex.crawls[0]}'] sql_where={ex.sql_where!r}{limit_note}"
    else:
        filter_line = (
            f"[index] mode=cdn crawls=['{ex.crawls[0]}'] hostnames={ex.hostnames} "
            f"domains={ex.domains} languages={ex.languages}{limit_note}"
        )
    lines = [
        "+ pip install --quiet duckdb huggingface_hub",
        "Successfully installed duckdb huggingface_hub",
        filter_line,
        "[index] enumerating index parquet files via the bucket API…",
        f"[index] {ex.scan_files} parquet file(s) to scan",
    ]
    if ex.sql_where:
        lines.append("[index] validating SQL filter…")
    lines += [
        "[index] running query + writing range-jobs CSV…",
        f"ESTIMATE n_records={ex.n_records} total_bytes={ex.total_bytes}",
    ]
    return lines


def fetch_log_lines(ex: Example) -> List[str]:
    """Mirror `cdxt -v repackage` fetch-job output."""
    out = ex.files[0] if ex.files else f"{ex.name}-001.warc.gz"
    return [
        f"+ cdxt -v repackage --target-source csv --csv-path ranges.csv "
        f"--warc-download-prefix hf://buckets/{config.CC_BUCKET} --hf-reader cdn "
        f"--prefix hf://buckets/{ex.bucket}/{ex.path}/{ex.name}",
        "INFO:cdx_toolkit:reading range jobs from ranges.csv",
        f"INFO:cdx_toolkit:{ex.n_records} records to fetch",
        "INFO:cdx_toolkit:fetching WARC ranges via hf-cdn (parallel_readers=48)",
        f"INFO:cdx_toolkit:{ex.n_records} records extracted",
        f"INFO:cdx_toolkit:wrote {out} ({_fmt_bytes(ex.total_bytes)})",
        "INFO:cdx_toolkit:execution time: 6s",
    ]