#!/usr/bin/env python3
"""
Script that generates a changelog for the repository and its submodules, and outputs it in the current directory.

NOTE: This script can be downloaded as-is and run from your repository.

Repos using this script:
 - ActivityWatch/activitywatch
 - ErikBjare/gptme

Manual actions needed to clean up for changelog:
 - Reorder modules in a logical order (aw-webui, aw-server, aw-server-rust, aw-watcher-window, aw-watcher-afk, ...)
 - Remove duplicate aw-webui entries
"""

import argparse
import logging
import os
import re
import shlex
from collections import defaultdict
from collections.abc import Collection
from dataclasses import dataclass
from pathlib import Path
from subprocess import PIPE, STDOUT
from subprocess import run as _run
from time import sleep
from typing import (
    Dict,
    List,
    Optional,
    Tuple,
)

import requests

logging.basicConfig(level=logging.DEBUG)
logger = logging.getLogger(__name__)


script_dir = Path(__file__).parent.resolve()


def main():
    parser = argparse.ArgumentParser(description="Generate changelog from git history")

    # repo info
    parser.add_argument("--org", default="ActivityWatch", help="GitHub organization")
    parser.add_argument("--repo", default="activitywatch", help="GitHub repository")
    parser.add_argument(
        "--project-title", default="ActivityWatch", help="Project title"
    )

    # settings
    last_tag = run("git describe --tags --abbrev=0").strip()  # get latest tag
    branch = run("git rev-parse --abbrev-ref HEAD").strip()  # get current branch name
    parser.add_argument(
        "--range", default=f"{last_tag}...{branch}", help="Git commit range"
    )
    parser.add_argument("--path", default=".", help="Path to git repo")

    # output
    parser.add_argument(
        "--output", default="changelog.md", help="Path to output changelog"
    )
    parser.add_argument(
        "--add-version-header",
        action="store_true",
        help="Add version header and adjust heading levels for docs",
    )

    # parse args
    args = parser.parse_args()
    since, until = args.range.split("...", 1)

    # preferred output order for submodules
    repo_order = [
        "activitywatch",
        "aw-server",
        "aw-server-rust",
        "aw-webui",
        "aw-watcher-afk",
        "aw-watcher-window",
        "aw-qt",
        "aw-core",
        "aw-client",
    ]

    build(
        args.org,
        args.repo,
        args.project_title,
        commit_range=(since, until),
        output_path=args.output,
        repo_order=repo_order,
        add_version_header=args.add_version_header,
    )


class CommitMsg:
    type: str
    subtype: str
    msg: str


@dataclass
class Commit:
    id: str
    msg: str
    org: str
    repo: str

    @property
    def msg_processed(self) -> str:
        """Generates links from commit and issue references (like 0c14d77, #123) to correct repo and such"""
        s = self.msg
        s = re.sub(
            rf"[^(-]https://github.com/{self.org}/([\-\w\d]+)/(issues|pulls)/(\d+)",
            rf"[#\3](https://github.com/{self.org}/\1/issues/\3)",
            s,
        )
        s = re.sub(
            r"#(\d+)",
            rf"[#\1](https://github.com/{self.org}/{self.repo}/issues/\1)",
            s,
        )
        s = re.sub(
            r"[\s\(][0-9a-f]{7}[\s\)]",
            rf"[`\0`](https://github.com/{self.org}/{self.repo}/issues/\0)",
            s,
        )
        # wrap html elements in backticks, if not already wrapped
        s = re.sub(r"(?<!`)<([^>]+)>(?!`)", r"`<\1>`", s)
        return s

    def parse_type(self) -> Optional[Tuple[str, str]]:
        # Needs to handle '!' indicating breaking change
        match = re.search(r"^(\w+)(\((.+)\))?[!]?:", self.msg)
        if match:
            type = match.group(1)
            subtype = match.group(3)
            if type in ["build", "ci", "fix", "feat"]:
                return type, subtype
        return None

    @property
    def type(self) -> Optional[str]:
        _type, _ = self.parse_type() or (None, None)
        return _type

    @property
    def subtype(self) -> Optional[str]:
        _, subtype = self.parse_type() or (None, None)
        return subtype

    def type_str(self) -> str:
        _type, subtype = self.parse_type() or (None, None)
        return f"{_type}" + (f"({subtype})" if subtype else "")

    def format(self) -> str:
        commit_link = commit_linkify(self.id, self.org, self.repo) if self.id else ""

        return f"{self.msg_processed}" + (f" ({commit_link})" if commit_link else "")


def run(cmd, cwd=".") -> str:
    logger.debug(f"Running in {cwd}: {cmd}")
    p = _run(shlex.split(cmd), stdout=PIPE, stderr=STDOUT, encoding="utf8", cwd=cwd)
    if p.returncode != 0:
        print(p.stdout)
        print(p.stderr)
        raise Exception
    return p.stdout


def pr_linkify(prid: str, org: str, repo: str) -> str:
    return f"[#{prid}](https://github.com/{org}/{repo}/pulls/{prid})"


def commit_linkify(commitid: str, org: str, repo: str) -> str:
    return f"[`{commitid}`](https://github.com/{org}/{repo}/commit/{commitid})"


def wrap_details(title, body, wraplines=5):
    """Wrap lines into a <details> element if body is longer than `wraplines`"""
    out = f"\n\n### {title}"
    wrap = body.strip().count("\n") > wraplines
    if wrap:
        out += "\n<details><summary>Click to expand</summary>\n<p>"
    out += f"\n{body.rstrip()}"
    if wrap:
        out += "\n\n</p>\n</details>"
    return out


contributor_emails = set()


def summary_repo(
    org: str,
    repo: str,
    path: str,
    commit_range: Tuple[str, str],
    filter_types: List[str],
    repo_order: List[str],
) -> str:
    if commit_range[1] == "0000000":
        # Happens when a submodule has been removed
        return ""
    if commit_range[0] == "0000000":
        # Happens when a submodule has been added
        commit_range = ("", "")  # no range = all commits for new submodule

    out = f"\n## 📦 {repo}"

    feats = ""
    fixes = ""
    misc = ""
    hidden = 0

    # pretty format is modified version of: https://stackoverflow.com/a/1441062/965332
    summary_bundle = run(
        f"git log {'...'.join(commit_range) if any(commit_range) else ''} --no-decorate --pretty=format:'%h%x09%an%x09%ae%x09%s'",
        cwd=path,
    )
    print(f"Found {len(summary_bundle.splitlines())} commits in {repo}")
    for line in summary_bundle.split("\n"):
        if line:
            _id, _author, email, msg = line.split("\t")
            # will add author email to contributor list
            # the `contributor_emails` is global and collected later
            contributor_emails.add(email)
            commit = Commit(id=_id, msg=msg, org=org, repo=repo)

            entry = f"\n - {commit.format()}"
            if commit.type == "feat":
                feats += entry
            elif commit.type == "fix":
                fixes += entry
            elif commit.type not in filter_types:
                misc += entry
            else:
                hidden += 1

    for name, entries in (
        ("✨ Features", feats),
        ("🐛 Fixes", fixes),
        ("🔨 Misc", misc),
    ):
        if entries:
            _count = len(entries.strip().split("\n"))
            title = f"{name} ({_count})"
            if "Misc" in name or "Fixes" in name:
                out += wrap_details(title, entries)
            else:
                out += f"\n\n### {title}\n"
                out += entries
    if hidden > 1:
        full_history_url = f"https://github.com/{org}/{repo}/compare/{commit_range[0]}...{commit_range[1]}"
        out += f"\n\n*(excluded {hidden} less relevant [commits]({full_history_url}))*"

    # NOTE: For now, these TODOs can be manually fixed for each changelog.
    # TODO: Fix issue where subsubmodules can appear twice (like aw-webui)
    # TODO: Use specific order (aw-webui should be one of the first, for example)
    summary_subrepos = run(
        f"git submodule summary --cached {commit_range[0]}", cwd=path
    )
    subrepos = {}
    for header, *_ in [s.split("\n") for s in summary_subrepos.split("\n\n")]:
        if header.startswith("fatal: not a git repository"):
            # Happens when a submodule has been removed
            continue
        if header.strip():
            if len(header.split(" ")) < 4:
                # Submodule may have been deleted
                continue

            _, name, crange, count = header.split(" ")
            commit_range = tuple(crange.split("...", 1))  # type: ignore
            count = count.strip().lstrip("(").rstrip("):")
            logger.info(
                f"Found {name}, looking up range: {commit_range} ({count} commits)"
            )
            name = name.strip(".").strip("/")

            subrepos[name] = summary_repo(
                org,
                name,
                f"{path}/{name}",
                commit_range,
                filter_types=filter_types,
                repo_order=repo_order,
            )

    # filter out subrepos with no commits (single line after stripping whitespace)
    subrepos = {
        name: output
        for name, output in subrepos.items()
        if len(output.strip().splitlines()) > 1
    }

    # pick subrepos in repo_order, and remove from dict
    for name in repo_order:
        if name in subrepos:
            out += "\n"
            out += subrepos[name]
            logger.info(f"{name:12} length: \t{len(subrepos[name])}")
            del subrepos[name]

    # add remaining repos
    for output in subrepos.values():
        out += "\n"
        out += output

    return out


# FIXME: Doesn't work, messy af, just gonna have to remove the aw-webui section by hand
def remove_duplicates(s: List[str], minlen=10, only_sections=True) -> List[str]:
    """
    Removes the longest sequence of repeated elements (they don't have to be adjacent), if sequence if longer than `minlen`.
    Preserves order of elements.
    """
    if len(s) < minlen:
        return s
    out = []
    longest: List[str] = []
    for i in range(len(s)):
        if i == 0 or s[i] not in out:
            # Not matching any previous line,
            # so add longest and new line to output, and reset longest
            if len(longest) < minlen:
                out.extend(longest)
            else:
                duplicate = "\n".join(longest)
                print(f"Removing duplicate '{duplicate[:80]}...'")
            out.append(s[i])
            longest = []
        else:
            # Matches a previous line, so add to longest
            # If longest is empty and only_sections is True, check that the line is a section start
            if only_sections:
                if not longest and s[i].startswith("#"):
                    longest.append(s[i])
                else:
                    out.append(s[i])
            else:
                longest.append(s[i])

    return out


def build(
    org: str,
    repo: str,
    project_name: str,
    commit_range: Tuple[str, str],
    output_path: str,
    repo_order: List[str],
    filter_types: Optional[List[str]] = None,
    add_version_header: bool = False,
):
    # provides a commit summary for the repo and subrepos, recursively looking up subrepos
    # NOTE: this must be done *before* `get_all_contributors` is called,
    #       as the latter relies on summary_repo looking up all users and storing in a global.
    if not filter_types:
        filter_types = ["build", "ci", "tests", "test"]

    logger.info("Generating commit summary")
    since, tag = commit_range
    output_changelog = summary_repo(
        org,
        repo,
        ".",
        commit_range=commit_range,
        filter_types=filter_types,
        repo_order=repo_order,
    )

    output_changelog = f"""
# Changelog

Changes since [{since}](https://github.com/{org}/{repo}/releases/tag/{since}):

{output_changelog}
    """.strip()

    # Would ideally sort by number of commits or something, but that's tricky
    usernames = sorted(get_all_contributors(), key=str.casefold)
    usernames = [u for u in usernames if not u.endswith("[bot]")]
    twitter_handles = get_twitter_of_ghusers(usernames)
    print(
        "Twitter handles: "
        + ", ".join("@" + handle for handle in twitter_handles.values() if handle),
    )

    output_contributors = f"""# Contributors

Thanks to everyone who contributed to this release:

{', '.join(('@' + username for username in usernames))}"""

    # Header starts here
    logger.info("Building final output")
    output = f"These are the release notes for {project_name} version {tag}.".strip()
    output += "\n\n"

    # hardcoded for now
    if repo == "activitywatch":
        output += "**New to ActivityWatch?** Check out the [website](https://activitywatch.net) and the [README](https://github.com/ActivityWatch/activitywatch/blob/master/README.md)."
        output += "\n\n"
        output += """# Installation

See the [getting started guide in the documentation](https://docs.activitywatch.net/en/latest/getting-started.html).
        """.strip()
        output += "\n\n"
        output += f"""# Downloads

 - [**Windows**](https://github.com/ActivityWatch/activitywatch/releases/download/{tag}/activitywatch-{tag}-windows-x86_64-setup.exe) (.exe, installer)
 - [**macOS**](https://github.com/ActivityWatch/activitywatch/releases/download/{tag}/activitywatch-{tag}-macos-x86_64.dmg) (.dmg)
 - [**Linux**](https://github.com/ActivityWatch/activitywatch/releases/download/{tag}/activitywatch-{tag}-linux-x86_64.zip) (.zip)
     """.strip()
        output += "\n\n"

    output += output_contributors.strip() + "\n\n"
    output += output_changelog.strip() + "\n\n"
    output += (
        f"**Full Changelog**: https://github.com/{org}/{repo}/compare/{since}...{tag}"
    )

    if repo == "activitywatch":
        output = output.replace("# activitywatch", "# activitywatch (bundle repo)")

    if add_version_header:
        output = f"# {tag}\n\n" + output
        output = output.replace("\n# Contributors\n", "\n## Contributors\n")
        output = output.replace("\n# Changelog\n", "\n## Changelog\n")

    with open(output_path, "w") as f:
        f.write(output)
    print(f"Wrote {len(output.splitlines())} lines to {output_path}")


def _resolve_email(email: str) -> Optional[str]:
    if "users.noreply.github.com" in email:
        username = email.split("@")[0]
        if "+" in username:
            username = username.split("+")[1]
        # TODO: Verify username is valid using the GitHub API
        print(f"Contributor: @{username}")
        return username
    else:
        resp = None
        backoff = 0
        max_backoff = 2
        while resp is None:
            if backoff >= max_backoff:
                logger.warning(f"Backed off {max_backoff} times, giving up")
                break
            try:
                logger.info(f"Sending request for {email}")
                _resp = requests.get(
                    f"https://api.github.com/search/users?q={email}+in%3Aemail"
                )
                _resp.raise_for_status()
                resp = _resp
                backoff = 0
            # if rate limit exceeded, back off
            except requests.exceptions.RequestException as e:
                if isinstance(e, requests.exceptions.HTTPError):
                    if e.response.status_code == 403:
                        logger.warning("Rate limit exceeded, backing off...")
                        backoff += 1
                        sleep(3)
                        continue
                else:
                    raise e
            finally:
                # Just to respect API limits...
                sleep(1)

        if resp:
            data = resp.json()
            if data["total_count"] == 0:
                logger.info(f"No match for email: {email}")
            if data["total_count"] > 1:
                logger.warning(f"Multiple matches for email: {email}")
            if data["total_count"] >= 1:
                username = data["items"][0]["login"]
                logger.info(f"Contributor: @{username}  (by email: {email})")
                return username
    return None


def get_all_contributors() -> set[str]:
    # TODO: Merge with contributor-stats?
    logger.info("Getting all contributors")

    # We will commit this file, to act as a cache (preventing us from querying GitHub API every time)
    filename = script_dir / "changelog_contributors.csv"

    # mapping from username to one or more emails
    usernames: Dict[str, set] = defaultdict(set)

    # some hardcoded ones, some that don't resolve...
    usernames["erikbjare"] |= {"erik.bjareholt@gmail.com", "erik@bjareho.lt"}
    usernames["iloveitaly"] |= {"iloveitaly@gmail.com"}
    usernames["kewde"] |= {"kewde@particl.io"}
    usernames["victorwinberg"] |= {"victor.m.winberg@gmail.com"}
    usernames["NicoWeio"] |= {"nico.weio@gmail.com"}
    usernames["2e3s"] |= {"2e3s19@gmail.com"}
    usernames["alwinator"] |= {"accounts@alwinschuster.at"}

    # read existing contributors, to avoid extra calls to the GitHub API
    if os.path.exists(filename):
        with open(filename, "r") as f:
            s = f.read()
        for line in s.split("\n"):
            if not line:
                continue
            username, *emails = line.split("\t")
            for email in emails:
                usernames[username].add(email)
        logger.info(f"Read {len(usernames)} contributors from {filename}")

    resolved_emails = set(
        email for email_set in usernames.values() for email in email_set
    )
    unresolved_emails = contributor_emails - resolved_emails
    for email in unresolved_emails:
        username_opt = _resolve_email(email)
        if username_opt:
            usernames[username_opt].add(email)

    with open(filename, "w") as f:
        for username, email_set in sorted(usernames.items()):
            emails_str = "\t".join(sorted(email_set))
            f.write(f"{username}\t{emails_str}")
            f.write("\n")

    logger.info(f"Wrote {len(usernames)} contributors to {filename}")

    email_to_username = {
        email: username for username, emails in usernames.items() for email in emails
    }

    return set(
        email_to_username[email]
        for email in contributor_emails
        if email in email_to_username
    )


def get_twitter_of_ghusers(ghusers: Collection[str]):
    logger.info("Getting twitter of GitHub usernames")

    # We will commit this file, to act as a cache (preventing us from querying GitHub API every time)
    filename = script_dir / "changelog_contributors_twitter.csv"

    twitter = {}

    # read existing contributors, to avoid extra calls to the GitHub API
    if os.path.exists(filename):
        with open(filename, "r") as f:
            s = f.read()
        for line in s.split("\n"):
            if not line:
                continue
            gh_username, twitter_username = line.split("\t")
            twitter[gh_username] = twitter_username
        logger.info(f"Read {len(twitter)} Twitter handles from {filename}")

    for username in ghusers:
        if username in twitter:
            continue
        try:
            resp = requests.get(f"https://api.github.com/users/{username}")
            resp.raise_for_status()
            data = resp.json()
        except Exception as e:
            logger.warning(f"Failed to get twitter of {username}: {e}")
            continue

        twitter_username = data["twitter_username"]
        if twitter_username:
            twitter[username] = twitter_username

    with open(filename, "w") as f:
        for username, twitter_username in sorted(twitter.items()):
            f.write(f"{username}\t{twitter_username}")
            f.write("\n")

    return twitter


if __name__ == "__main__":
    main()