#!/usr/bin/env python3
from __future__ import annotations

import argparse
import hashlib
import json
from http.server import BaseHTTPRequestHandler, ThreadingHTTPServer
from pathlib import Path
from urllib.parse import urlparse

def parse_args():
    p=argparse.ArgumentParser(description="CM95 MySQL vs PostgreSQL PBF comparison server")
    p.add_argument("--host",default="0.0.0.0")
    p.add_argument("--port",type=int,default=18889)
    p.add_argument("--mysql-pbf-root",required=True)
    p.add_argument("--postgres-pbf-root",required=True)
    p.add_argument("--mysql-release",default="mysql-current")
    p.add_argument("--postgres-release",default="postgres-current")
    return p.parse_args()

def sha256(path: Path) -> str:
    h=hashlib.sha256()
    with path.open("rb") as f:
        for b in iter(lambda:f.read(1024*1024),b""):
            h.update(b)
    return h.hexdigest()

def pbf_inventory(root: Path):
    return {str(p.relative_to(root)):p for p in root.rglob("*.pbf") if p.is_file()}

def main():
    args=parse_args()
    web=Path(__file__).resolve().parent
    mysql_root=Path(args.mysql_pbf_root).resolve()
    pg_root=Path(args.postgres_pbf_root).resolve()
    html=web/"mysql_postgresql_compare_north_kyushu.html"
    style=web/"resources/style.s52.json"
    assets=web/"assets"
    resources=web/"resources"
    for p in [mysql_root,pg_root,html,style,assets/"maplibre-gl.js",assets/"maplibre-gl.css",resources/"sprite.json",resources/"sprite.png"]:
        if not p.exists():
            raise SystemExit(f"missing: {p}")
    mi=pbf_inventory(mysql_root)
    pi=pbf_inventory(pg_root)
    common=sorted(set(mi)&set(pi))
    identical=0
    different=[]
    for rel in common:
        if mi[rel].stat().st_size==pi[rel].stat().st_size and sha256(mi[rel])==sha256(pi[rel]):
            identical+=1
        elif len(different)<50:
            different.append(rel)
    info={
        "mysql":{"release":args.mysql_release,"files":len(mi),"root":str(mysql_root)},
        "postgresql":{"release":args.postgres_release,"files":len(pi),"root":str(pg_root)},
        "compare":{"common":len(common),"identical":identical,"different":len(common)-identical,"different_examples":different},
    }

    class Handler(BaseHTTPRequestHandler):
        def send(self,data:bytes,ctype:str,status=200):
            self.send_response(status)
            self.send_header("Content-Type",ctype)
            self.send_header("Content-Length",str(len(data)))
            self.send_header("Cache-Control","no-cache")
            self.send_header("Access-Control-Allow-Origin","*")
            self.end_headers()
            self.wfile.write(data)
        def serve_file(self,path:Path,ctype:str):
            if not path.is_file():
                self.send_error(404)
                return
            self.send(path.read_bytes(),ctype)
        def do_GET(self):
            path=urlparse(self.path).path
            if path in ("/","/index.html","/compare"):
                return self.serve_file(html,"text/html; charset=utf-8")
            if path=="/api/info":
                return self.send(json.dumps(info,ensure_ascii=False,indent=2).encode(),"application/json; charset=utf-8")
            if path=="/style.json":
                return self.serve_file(style,"application/json; charset=utf-8")
            if path in ("/assets/maplibre-gl.js","/assets/maplibre-gl.css"):
                fn=path.rsplit("/",1)[-1]
                ct="application/javascript; charset=utf-8" if fn.endswith(".js") else "text/css; charset=utf-8"
                return self.serve_file(assets/fn,ct)
            if path in ("/sprite.json","/sprite.png","/sprite@2x.json","/sprite@2x.png"):
                fn=path[1:]
                ct="application/json; charset=utf-8" if fn.endswith(".json") else "image/png"
                return self.serve_file(resources/fn,ct)
            for prefix,root in (("/mysql/",mysql_root),("/postgres/",pg_root)):
                if path.startswith(prefix) and path.endswith(".pbf"):
                    rel=path[len(prefix):]
                    parts=rel.split("/")
                    if len(parts)!=3 or not all(x.isdigit() for x in [parts[0],parts[1],parts[2][:-4]]):
                        self.send_error(404); return
                    return self.serve_file(root/rel,"application/vnd.mapbox-vector-tile")
            self.send_error(404)
        def log_message(self,fmt,*args):
            pass

    print(json.dumps(info,ensure_ascii=False,indent=2))
    print(f"Compare: http://{args.host}:{args.port}/")
    ThreadingHTTPServer((args.host,args.port),Handler).serve_forever()

if __name__=="__main__":
    main()