#!/usr/bin/env python
#
# Pre-build script: gzip webui/index.html into a PROGMEM C header so the
# webconfig portal can serve the page straight from flash with
# Content-Encoding: gzip. The generated header is tracked so ESP32 targets
# that replace extra_scripts still compile from a clean checkout; this script
# refreshes it whenever the source page (or this script) is newer.
#
# Output: src/helpers/esp32/WebConfigHtml.h
#   WEBCONFIG_HTML_GZ[]   - gzipped page (PROGMEM)
#   WEBCONFIG_HTML_GZ_LEN - byte length
#   WEBCONFIG_HTML_ETAG   - quoted strong ETag (sha256 prefix of the gz body)

import gzip
import hashlib
import os
import sys

# PlatformIO/SCons injects Import(). Keep the generator directly runnable as
# well so maintainers can refresh and verify the tracked header without first
# starting a firmware build.
try:
    Import("env")  # noqa: F821
except NameError:
    pass

SOURCE = os.path.join("webui", "index.html")
OUTPUT = os.path.join("src", "helpers", "esp32", "WebConfigHtml.h")
# __file__ is not defined inside PIO/SCons-executed extra_scripts
SCRIPT = os.path.join("scripts", "generate_webconfig_html.py")


def status(msg):
    sys.stderr.write("WebConfig HTML: %s\n" % msg)


def needs_rebuild():
    if not os.path.isfile(OUTPUT):
        return True
    out_mtime = os.path.getmtime(OUTPUT)
    if os.path.getmtime(SOURCE) > out_mtime:
        return True
    if os.path.isfile(SCRIPT) and os.path.getmtime(SCRIPT) > out_mtime:
        return True
    return False


def main():
    if not os.path.isfile(SOURCE):
        status("ERROR: %s not found" % SOURCE)
        sys.exit(2)

    if not needs_rebuild():
        return

    with open(SOURCE, "rb") as f:
        raw = f.read()

    # mtime=0 keeps the gzip output (and therefore the ETag) deterministic
    gz = gzip.compress(raw, compresslevel=9, mtime=0)
    etag = hashlib.sha256(gz).hexdigest()[:16]

    lines = []
    lines.append("// Auto-generated by scripts/generate_webconfig_html.py from %s" % SOURCE.replace(os.sep, "/"))
    lines.append("// DO NOT EDIT - edit webui/index.html instead.")
    lines.append("#pragma once")
    lines.append("#include <stdint.h>")
    lines.append("#include <pgmspace.h>")
    lines.append("")
    lines.append("const uint32_t WEBCONFIG_HTML_GZ_LEN = %d;" % len(gz))
    lines.append('const char WEBCONFIG_HTML_ETAG[] = "\\"%s\\"";' % etag)
    lines.append("const uint8_t WEBCONFIG_HTML_GZ[] PROGMEM = {")
    for i in range(0, len(gz), 16):
        chunk = gz[i:i + 16]
        lines.append("  " + "".join("0x%02x," % b for b in chunk))
    lines.append("};")
    lines.append("")

    os.makedirs(os.path.dirname(OUTPUT), exist_ok=True)
    with open(OUTPUT, "w") as f:
        f.write("\n".join(lines))

    status("%s -> %s (%d bytes raw, %d bytes gzipped)" % (SOURCE, OUTPUT, len(raw), len(gz)))


# This script is attached only to esp32_base. Generate unconditionally here:
# CPPDEFINES is not fully resolved when PlatformIO loads pre-scripts, so trying
# to detect the final role at this point can leave a stale embedded page.
# Non-WebConfig ESP32 builds do not compile the generated data into firmware.
main()