import argparse
import enum
import glob
import hashlib
import os
import requests
import sys
import tempfile
import time
import yaml

from pathlib import Path
from PIL import Image
from urllib import parse

import dump_trace_images

TRACES_DB_PATH = os.getcwd() + "/traces-db/"
RESULTS_PATH = os.getcwd() + "/results/"

def replay(trace_path, device_name):
    success = dump_trace_images.dump_from_trace(trace_path, [], device_name)

    if not success:
        print("[check_image] Trace %s couldn't be replayed. See above logs for more information." % (str(trace_path)))
        return None, None, None
    else:
        base_path = trace_path.parent
        file_name = trace_path.name
        files = glob.glob(str(base_path / "test" / device_name / (file_name + "-*" + ".png")))
        assert(files)
        image_file = files[0]
        files = glob.glob(str(base_path / "test" / device_name / (file_name + ".log")))
        assert(files)
        log_file = files[0]
        return hashlib.md5(Image.open(image_file).tobytes()).hexdigest(), image_file, log_file

def download_metadata(repo_url, repo_commit, trace_path):
    # The GitLab API doesn't want the .git postfix
    url = repo_url
    if url.endswith(".git"):
        url = url[:-4]
    url = parse.urlparse(url)

    url_path = url.path
    if url_path.startswith("/"):
        url_path = url_path[1:]

    gitlab_api_url = url.scheme + "://" + url.netloc + "/api/v4/projects/" + parse.quote_plus(url_path)

    r = requests.get(gitlab_api_url + "/repository/files/%s/raw?ref=%s" % (parse.quote_plus(trace_path), repo_commit))
    metadata_raw = r.text.strip().split('\n')
    metadata = dict(line.split(' ', 1) for line in metadata_raw[1:])
    oid = metadata["oid"][7:] if metadata["oid"].startswith('sha256:') else metadata["oid"]
    size = int(metadata['size'])

    return oid, size

def download_trace(repo_url, repo_commit, trace_path, oid, size):
    headers = {
        "Accept": "application/vnd.git-lfs+json",
        "Content-Type": "application/vnd.git-lfs+json"
    }
    json = {
        "operation": "download",
        "transfers": [ "basic" ],
        "ref": { "name": "refs/heads/%s" % repo_commit },
        "objects": [
            {
                "oid": oid,
                "size": size
            }
        ]
    }

    # The LFS API really wants the .git postfix...
    if not repo_url.endswith(".git"):
        repo_url += ".git"

    r = requests.post(repo_url + "/info/lfs/objects/batch", headers=headers, json=json)
    url = r.json()["objects"][0]["actions"]["download"]["href"]
    open(TRACES_DB_PATH + trace_path, "wb").write(requests.get(url).content)

def checksum(filename, hash_factory=hashlib.sha256, chunk_num_blocks=128):
    h = hash_factory()
    with open(filename,'rb') as f:
        for chunk in iter(lambda: f.read(chunk_num_blocks*h.block_size), b''):
            h.update(chunk)
    return h.digest()

def ensure_trace(repo_url, repo_commit, trace):
    trace_path = TRACES_DB_PATH + trace['path']
    if repo_url is None:
        assert(repo_commit is None)
        assert(os.path.exists(trace_path))
        return

    os.makedirs(os.path.dirname(trace_path), exist_ok=True)

    if os.path.exists(trace_path):
        local_oid = checksum(trace_path)

    remote_oid, size = download_metadata(repo_url, repo_commit, trace['path'])

    if not os.path.exists(trace_path) or local_oid != remote_oid:
        print("[check_image] Downloading trace %s" % (trace['path']), end=" ", flush=True)
        download_time = time.time()
        download_trace(repo_url, repo_commit, trace['path'], remote_oid, size)
        print("took %ds." % (time.time() - download_time), flush=True)

def check_trace(repo_url, repo_commit, device_name, trace, expectation):
    ensure_trace(repo_url, repo_commit, trace)

    trace_path = Path(TRACES_DB_PATH + trace['path'])
    checksum, image_file, log_file = replay(trace_path, device_name)
    if checksum is None:
            return False
    elif checksum == expectation['checksum']:
            print("[check_image] Images match for %s" % (trace['path']))
            ok = True
    else:
            print("[check_image] Images differ for %s (expected: %s, actual: %s)" %
                  (trace['path'], expectation['checksum'], checksum))
            print("[check_image] For more information see "
                  "https://gitlab.freedesktop.org/mesa/mesa/blob/master/.gitlab-ci/tracie/README.md")
            ok = False

    trace_dir = os.path.split(trace['path'])[0]
    results_path = os.path.join(RESULTS_PATH, trace_dir, "test", device_name)
    os.makedirs(results_path, exist_ok=True)
    os.rename(log_file, os.path.join(results_path, os.path.split(log_file)[1]))
    if not ok or os.environ.get('TRACIE_STORE_IMAGES', '0') == '1':
            os.rename(image_file, os.path.join(results_path, os.path.split(image_file)[1]))

    return ok

def main():
    parser = argparse.ArgumentParser()
    parser.add_argument('--file', required=True,
                        help='the name of the traces.yml file listing traces and their checksums for each device')
    parser.add_argument('--device-name', required=True,
                        help="the name of the graphics device used to replay traces")

    args = parser.parse_args()

    with open(args.file, 'r') as f:
        y = yaml.safe_load(f)

    if "traces-db" in y:
        repo = y["traces-db"]["repo"]
        commit_id = y["traces-db"]["commit"]
    else:
        repo = None
        commit_id = None

    traces = y['traces']
    all_ok = True
    for trace in traces:
        for expectation in trace['expectations']:
                if expectation['device'] == args.device_name:
                        ok = check_trace(repo, commit_id, args.device_name, trace, expectation)
                        all_ok = all_ok and ok

    sys.exit(0 if all_ok else 1)

if __name__ == "__main__":
    main()