import logging
import os

import yaml

from lib.binary import is_binary_or_large
from lib.db import DB
from lib.git import Git
from lib.obs import OBS
from lib.proxy_sha256 import ProxySHA256, md5
from lib.tree_builder import TreeBuilder


class GitExporter:
    def __init__(self, api_url, project, package, repodir):
        self.obs = OBS()
        self.project = project
        self.package = package
        # TODO: Store the api url in the revision
        self.obs.change_url(api_url)
        self.proxy_sha256 = ProxySHA256(self.obs, enabled=True)
        self.git = Git(
            repodir,
            committer="Git OBS Bridge",
            committer_email="obsbridge@suse.de",
        ).create()
        self.state_file = os.path.join(self.git.path, ".git", "_flat_state.yaml")
        self.gc_interval = 200

    def download(self, revision):
        obs_files = self.obs.files(revision.project, revision.package, revision.srcmd5)
        git_files = {
            (f.name, f.stat().st_size, md5(f))
            for f in self.git.path.iterdir()
            if f.is_file() and f.name not in (".gitattributes")
        }

        # Overwrite ".gitattributes" with the
        self.git.add_default_lfs_gitattributes(force=True)

        # Download each file in OBS if it is not a binary (or large)
        # file
        for (name, size, file_md5) in obs_files:
            # Validate the MD5 of the downloaded file
            if md5(self.git.path / name) != file_md5:
                raise Exception(f"Download error in {name}")
            self.git.add(name)

    def set_gc_interval(self, gc):
        self.gc_interval = gc

    def export_as_git(self):
        db = DB()
        tree = TreeBuilder(db).build(self.project, self.package)
        flats = tree.as_flat_list()

        branch_state = {"factory": None, "devel": None}
        state_data = dict()
        if os.path.exists(self.state_file):
            with open(self.state_file, "r") as f:
                state_data = yaml.safe_load(f)
                if type(state_data) != dict:
                    state_data = {}
        left_to_commit = []
        for flat in reversed(flats):
            found_state = False
            for branch in ["factory", "devel"]:
                if flat.commit.dbid == state_data.get(branch):
                    branch_state[branch] = flat.commit
                    flat.commit.git_commit = self.git.branch_head(branch)
                    logging.debug(
                        f"Found {self.git.path}'s {branch} branch in state {flat}"
                    )
                    left_to_commit = []
                    found_state = True
            if not found_state:
                left_to_commit.append(flat)

        gc_cnt = self.gc_interval
        if len(left_to_commit) > 0:
            self.git.gc()
        for flat in left_to_commit:
            gc_cnt -= 1
            if gc_cnt <= 0 and self.gc_interval:
                self.git.gc()
                gc_cnt = self.gc_interval
            logging.debug(f"Committing {flat}")
            self.commit_flat(flat, branch_state)

    def commit_flat(self, flat, branch_state):
        parents = []
        self.git.checkout(flat.branch)

        # Overwrite ".gitattributes" with the
        self.git.add_default_lfs_gitattributes(force=True)

        if flat.parent1:
            parents.append(flat.parent1.git_commit)
        if flat.parent2:
            parents.append(flat.parent2.git_commit)
        to_download, to_delete = flat.commit.calc_delta(branch_state[flat.branch])
        for file in to_delete:
            self.git.remove(file)
        for file, size, md5 in to_download:
            # have such files been detected as text mimetype before?
            is_text = self.proxy_sha256.is_text(file.name)
            if not is_text and is_binary_or_large(file.name, size):
                file_sha256 = self.proxy_sha256.get_or_put(
                    flat.commit.project,
                    flat.commit.package,
                    file.name,
                    flat.commit.expanded_srcmd5,
                    md5,
                    size,
                )
                self.git.add_lfs(file.name, file_sha256["sha256"], size)
            else:
                self.obs.download(
                    flat.commit.project,
                    flat.commit.package,
                    file.name,
                    flat.commit.expanded_srcmd5,
                    self.git.path,
                    file_md5=md5,
                )
                self.git.add(file)

        commit = self.git.commit(
            f"OBS User {flat.commit.userid}",
            "null@suse.de",
            flat.commit.commit_time,
            # TODO: Normalize better the commit message
            f"{flat.commit.comment}\n\n{flat.commit}",
            allow_empty=True,
            parents=parents,
        )
        flat.commit.git_commit = commit
        branch_state[flat.branch] = flat.commit
        with open(self.state_file, "w") as f:
            data = {}
            for branch in ["factory", "devel"]:
                commit = branch_state[branch]
                if commit:
                    data[branch] = commit.dbid
            yaml.dump(data, f)