#!/usr/bin/env python

import argparse
import json
import sys

from urllib.parse import parse_qs, urlencode, urlparse, urlunparse


def validate_schema(schema):
    if "format" not in schema:
        raise ValueError("No format")
    if schema["format"] != "clicks":
        raise ValueError(f"Unsupported format: {schema['format']}")
    if "version" not in schema:
        raise ValueError("No version")
    if schema["version"] != "1.0":
        raise ValueError(f"Unsupported version: {schema['version']}")


def cleanup_url(url):
    parts = urlparse(url)
    query = parse_qs(parts.query, keep_blank_values=True)
    if "activeTab" in query:
        new_query = urlencode({"activeTab": query["activeTab"]})
    else:
        new_query = ""
    parts = parts._replace(query=new_query)
    return urlunparse(parts)


def bad_event(event):
    # There is a confusing causing "header" event to be reported as click events
    # "header" events can be reconized by containing brands in tag or x > 1
    return "Chromium" in event["tag"] or event["x"] > 1.0


def merge(input_files, output_fh):
    merged = {
        "format": "clicks",
        "version": "1.0",
    }

    schemas = []
    for input_file in input_files:
        with open(input_file, "r", encoding="utf-8") as in_fh:
            try:
                schema = json.load(in_fh)
                validate_schema(schema)
                schemas.append(schema)
            except json.JSONDecodeError:
                print(f"{input_file}: Invalid JSON, ignored", file=sys.stderr)
                continue
            except ValueError:
                print(f"{input_file}: Invalid JSON, ignored", file=sys.stderr)
                continue

    max_width = 0.0
    max_height = 0.0
    for schema in schemas:
        if schema["width"] > max_width:
            max_width = schema["width"]
        if schema["height"] > max_height:
            max_height = schema["height"]

    merged["width"] = max_width
    merged["height"] = max_height
    url_events = {}

    for schema in schemas:
        events = None
        for event in schema["events"]:
            if "url" in event:
                url = cleanup_url(event["url"])
                events = url_events.get(url, None)
                if events is None:
                    events = []
                    url_events[url] = {
                        "url": event["url"],
                        "events": events,
                    }
                else:
                    events = events["events"]
            elif not bad_event(event):
                # x and y in event is already in percentage of width so should scale
                events.append(event)

    merged["events"] = []
    for url, events in url_events.items():
        merged["events"].append(
            {
                "url": events["url"],
            }
        )
        merged["events"].extend(events["events"])

    json.dump(merged, output_fh)


def main():
    parser = argparse.ArgumentParser(
        prog="merge",
        description="Merges multiple session reports into one",
    )
    parser.add_argument(
        "-o",
        "--output",
        nargs="?",
        help="output to FILE instead of stdout",
        metavar="FILE",
    )
    parser.add_argument("filename", nargs="+", help="input files")

    args = parser.parse_args()

    if args.output is not None:
        with open(args.output, "w", encoding="utf-8") as out:
            merge(args.filename, out)
    else:
        merge(args.filename, sys.stdout)


if __name__ == "__main__":
    main()