use cuddle_please_frontend::PleaseConfig;

use ::semver::Version;
use anyhow::Context;

use cuddle_please_misc::{
    changelog_parser, get_most_significant_version, ChangeLogBuilder, DynRemoteGitClient,
    NextVersion, VcsClient,
};

pub struct ReleaseCommandHandler {
    config: PleaseConfig,
    git_client: VcsClient,
    gitea_client: DynRemoteGitClient,
}

impl ReleaseCommandHandler {
    pub fn new(
        config: PleaseConfig,
        git_client: VcsClient,
        gitea_client: DynRemoteGitClient,
    ) -> Self {
        Self {
            config,
            git_client,
            gitea_client,
        }
    }

    pub fn execute(&self, dry_run: bool) -> anyhow::Result<()> {
        tracing::debug!("running command: release");
        let owner = self.config.get_owner();
        let repository = self.config.get_repository();
        let branch = self.config.get_branch();
        let source = self.config.get_source();

        // 2. Parse the cuddle.please.yaml let cuddle.please.yaml take precedence
        // 2a. if not existing use default.
        // 2b. if not in a git repo abort. (unless --no-vcs is turned added)

        // 3. Create gitea client and do a health check
        self.gitea_client
            .connect(owner, repository)
            .context("failed to connect to gitea repository")?;
        // 4. Fetch git tags for the current repository
        let tags = self.gitea_client.get_tags(owner, repository)?;

        let significant_tag = get_most_significant_version(tags.iter().collect());

        // 5. Fetch git commits since last git tag
        let commits = self.gitea_client.get_commits_since(
            owner,
            repository,
            significant_tag.map(|st| st.commit.sha.as_str()),
            branch,
        )?;

        // 7. Create a versioning client
        let current_version = significant_tag
            .map(|st| Version::try_from(st).unwrap())
            .unwrap_or(Version::new(0, 1, 0));

        // 8. Parse conventional commits and determine next version

        let commit_strs = commits
            .iter()
            .map(|c| c.commit.message.as_str())
            .collect::<Vec<&str>>();

        if commit_strs.is_empty() {
            tracing::info!("no commits to base release on");
            return Ok(());
        }

        let next_version = current_version.next(&commit_strs);

        // Compose changelog
        let builder = ChangeLogBuilder::new(&commit_strs, next_version.to_string()).build();

        let changelog_placement = source.join("CHANGELOG.md");

        let changelog = match std::fs::read_to_string(&changelog_placement).ok() {
            Some(existing_changelog) => builder.prepend(existing_changelog)?,
            None => builder.generate()?,
        };

        let changelog_last_changes = changelog_parser::last_changes(&changelog)?;

        // 9b. check for release commit and release, if release exists continue
        // 10b. create release
        if let Some(first_commit) = commit_strs.first() {
            if first_commit.contains("chore(release): ") {
                if !dry_run {
                    self.gitea_client.create_release(
                        owner,
                        repository,
                        &next_version.to_string(),
                        &changelog_last_changes.unwrap(),
                        !next_version.pre.is_empty(),
                    )?;
                } else {
                    tracing::debug!("creating release (dry_run)");
                }

                return Ok(());
            }
        }

        // 9a. Create / Update Pr
        // Create or update branch
        self.git_client.checkout_branch()?;

        std::fs::write(changelog_placement, changelog.as_bytes())?;

        self.git_client
            .commit_and_push(next_version.to_string(), dry_run)?;

        let _pr_number = match self.gitea_client.get_pull_request(owner, repository)? {
            Some(existing_pr) => {
                if !dry_run {
                    self.gitea_client.update_pull_request(
                        owner,
                        repository,
                        &next_version.to_string(),
                        &changelog_last_changes.unwrap(),
                        existing_pr,
                    )?
                } else {
                    tracing::debug!("updating pull request (dry_run)");
                    1
                }
            }
            None => {
                if !dry_run {
                    self.gitea_client.create_pull_request(
                        owner,
                        repository,
                        &next_version.to_string(),
                        &changelog,
                        branch,
                    )?
                } else {
                    tracing::debug!("creating pull request (dry_run)");
                    1
                }
            }
        };

        Ok(())
    }
}