#!/usr/bin/env python3

# vim: sw=2 ts=2 ex:

import os

import glob

from .run import run;

from .sha256 import sha256, sha256_file;

def build(args):
  os.makedirs(".build-cache/", exist_ok = 1);

  cc = "gcc";

  cppflags = ("-D", "_GNU_SOURCE");
  
  cppflags += ("-I", ".");
  
  cflags = ();
  
  match args.build_type:
    case "debug":
      cppflags += ("-D", "DEBUG_BUILD_TYPE");
      
      cflags += ("-g", );
      
      cflags += ("-Werror", );
      cflags += ("-Wall", );
      cflags += ("-Wextra", );
      cflags += ("-Wconversion", );
      cflags += ("-Wsign-conversion", );
      cflags += ("-Wfloat-conversion", );
      cflags += ("-Warith-conversion", );
      cflags += ("-Wno-strict-prototypes", );
      cflags += ("-Wfatal-errors", );
      
      cflags += ("-Wno-unused", );
    
    case "release":
      cppflags += ("-D", "RELEASE_BUILD_TYPE");
      
      cflags += ("-Werror", );
      cflags += ("-Wall", );
      cflags += ("-Wextra", );
      cflags += ("-Wstrict-prototypes", );
      cflags += ("-Wconversion", );
      cflags += ("-Wsign-conversion", );
      cflags += ("-Wfloat-conversion", );
      cflags += ("-Warith-conversion", );
      cflags += ("-Wstrict-prototypes", );
      cflags += ("-Wfatal-errors", );
    
    case _:
      print("unknown build type {repr(args.build_type)}");
      exit(1);
  
  objs = [];

  for src in sorted(glob.glob("**/*.c", recursive = 1)):
    command = (cc, ) + ("-MM", ) + cppflags + (src, );
    
    shas = (sha256_file(src), );
    
    dep = ".build-cache/" + sha256((command, *shas)) + ".dep";
    
    if not os.path.exists(dep):
      command += ("-MF", dep);
    
      run(command);
    
    with open(dep) as stream:
      for header in stream.read().replace("\\\n", " ").split()[2:]:
        shas += (sha256_file(header), );
    
    command = (cc, ) + ("-c", ) + cppflags + cflags + (src, );
    
    sha = sha256((command, *shas));
    
    obj = ".build-cache/" + sha + ".o";
    
    if not os.path.exists(obj):
      print(f"Compiling {src} ...");
      
      command += ("-o", obj);
      
      run(command);
    
    objs.append(obj);

  ld = "gcc";

  ldflags = ();

  ldlibs = ("-lm", "-lreadline");

  command = (ld, *ldflags, *objs, *ldlibs)

  exe = ".build-cache/" + sha256((command, ));

  if not os.path.exists(exe):
    print(f"Linking ...");
    
    command += ("-o", exe);
    
    run(command);
  
  return exe;