use std::{
    io::Read,
    ops::Deref,
    path::{Path, PathBuf},
    sync::{Arc, Mutex},
};

use ::semver::Version;
use anyhow::Context;
use clap::{Parser, Subcommand};
use cuddle_please_frontend::{gatheres::ConfigArgs, PleaseConfigBuilder};
use cuddle_please_misc::{
    changelog_parser, get_most_significant_version, ChangeLogBuilder, ConsoleUi, DynUi,
    GiteaClient, GlobalArgs, NextVersion, StdinFn, VcsClient,
};

#[derive(Parser)]
#[command(author, version, about, long_about = None)]
pub struct Command {
    #[command(flatten)]
    global: GlobalArgs,

    #[command(flatten)]
    config: ConfigArgs,

    #[command(subcommand)]
    commands: Option<Commands>,

    #[clap(skip)]
    ui: DynUi,

    #[clap(skip)]
    stdin: StdinFn,
}

impl Default for Command {
    fn default() -> Self {
        Self::new()
    }
}

impl Command {
    pub fn new() -> Self {
        let args = std::env::args();

        Self::new_from_args_with_stdin(Some(ConsoleUi::default()), args, || {
            let mut input = String::new();
            std::io::stdin().read_to_string(&mut input)?;
            Ok(input)
        })
    }

    pub fn new_from_args<I, T, UIF>(ui: Option<UIF>, i: I) -> Self
    where
        I: IntoIterator<Item = T>,
        T: Into<std::ffi::OsString> + Clone,
        UIF: Into<DynUi>,
    {
        let mut s = Self::parse_from(i);

        if let Some(ui) = ui {
            s.ui = ui.into();
        }

        s
    }

    pub fn new_from_args_with_stdin<I, T, F, UIF>(ui: Option<UIF>, i: I, input: F) -> Self
    where
        I: IntoIterator<Item = T>,
        T: Into<std::ffi::OsString> + Clone,
        F: Fn() -> anyhow::Result<String> + Send + Sync + 'static,
        UIF: Into<DynUi>,
    {
        let mut s = Self::parse_from(i);

        if let Some(ui) = ui {
            s.ui = ui.into();
        }
        s.stdin = Some(Arc::new(Mutex::new(input)));

        s
    }

    pub fn execute(self, current_dir: Option<&Path>) -> anyhow::Result<()> {
        let config = self.build_config(current_dir)?;

        match &self.commands {
            Some(Commands::Release {}) => {
                tracing::debug!("running bare command");
                // 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)
                let git_client = self.get_git(config.get_source())?;

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

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

                // 5. Fetch git commits since last git tag
                let commits = gitea_client.get_commits_since(
                    config.get_owner(),
                    config.get_repository(),
                    significant_tag.map(|st| st.commit.sha.clone()),
                    config.get_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 = config.get_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 !self.global.dry_run {
                            gitea_client.create_release(
                                config.get_owner(),
                                config.get_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
                git_client.checkout_branch()?;

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

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

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

            Some(Commands::Config { command }) => match command {
                ConfigCommand::List { .. } => {
                    tracing::debug!("running command: config list");

                    self.ui.write_str_ln("cuddle-config");
                }
            },
            Some(Commands::Gitea { command }) => {
                let git_url = url::Url::parse(config.get_api_url())?;

                let mut url = String::new();
                url.push_str(git_url.scheme());
                url.push_str("://");
                url.push_str(&git_url.host().unwrap().to_string());
                if let Some(port) = git_url.port() {
                    url.push_str(format!(":{port}").as_str());
                }

                let client = GiteaClient::new(url, self.global.token);
                match command {
                    GiteaCommand::Connect {} => {
                        client.connect(config.get_owner(), config.get_repository())?;
                        self.ui.write_str_ln("connected succesfully go gitea");
                    }
                    GiteaCommand::Tags { command } => match command {
                        Some(GiteaTagsCommand::MostSignificant {}) => {
                            let tags =
                                client.get_tags(config.get_owner(), config.get_repository())?;

                            match get_most_significant_version(tags.iter().collect()) {
                                Some(tag) => {
                                    self.ui.write_str_ln(&format!(
                                        "found most significant tags: {}",
                                        tag.name
                                    ));
                                }
                                None => {
                                    self.ui.write_str_ln("found no tags with versioning schema");
                                }
                            }
                        }
                        None => {
                            let tags =
                                client.get_tags(config.get_owner(), config.get_repository())?;
                            self.ui.write_str_ln("got tags from gitea");
                            for tag in tags {
                                self.ui.write_str_ln(&format!("- {}", tag.name))
                            }
                        }
                    },
                    GiteaCommand::SinceCommit { sha, branch } => {
                        let commits = client.get_commits_since(
                            config.get_owner(),
                            config.get_repository(),
                            Some(sha),
                            branch,
                        )?;
                        self.ui.write_str_ln("got commits from gitea");
                        for commit in commits {
                            self.ui.write_str_ln(&format!("- {}", commit.get_title()))
                        }
                    }
                    GiteaCommand::CheckPr {} => {
                        let pr =
                            client.get_pull_request(config.get_owner(), config.get_repository())?;

                        match pr {
                            Some(index) => {
                                self.ui.write_str_ln(&format!(
                                    "found cuddle-please (index={}) pr from gitea",
                                    index
                                ));
                            }
                            None => {
                                self.ui.write_str_ln("found no cuddle-please pr from gitea");
                            }
                        }
                    }
                }
            }
            Some(Commands::Doctor {}) => {
                match std::process::Command::new("git").arg("-v").output() {
                    Ok(o) => {
                        let stdout = std::str::from_utf8(&o.stdout).unwrap_or("");
                        self.ui.write_str_ln(&format!("OK: {}", stdout));
                    }
                    Err(e) => {
                        self.ui
                            .write_str_ln(&format!("WARNING: git is not installed: {}", e));
                    }
                }
            }
            None => {}
        }

        Ok(())
    }

    fn build_config(
        &self,
        current_dir: Option<&Path>,
    ) -> Result<cuddle_please_frontend::PleaseConfig, anyhow::Error> {
        let mut builder = &mut PleaseConfigBuilder::new();
        if self.global.config_stdin {
            if let Some(stdin_fn) = self.stdin.clone() {
                let output = (stdin_fn.lock().unwrap().deref())();
                builder = builder.with_stdin(output?);
            }
        }
        let current_dir = get_current_path(current_dir, self.config.source.clone())?;
        let config = builder
            .with_config_file(&current_dir)
            .with_execution_env(std::env::vars())
            .with_cli(self.config.clone())
            .build()?;
        Ok(config)
    }

    fn get_git(&self, current_dir: &Path) -> anyhow::Result<VcsClient> {
        VcsClient::new_git(current_dir)
    }

    fn get_gitea_client(&self) -> GiteaClient {
        GiteaClient::new(
            self.config.api_url.clone().expect("api_url to be set"),
            self.global.token.clone(),
        )
    }
}

#[derive(Debug, Clone, Subcommand)]
pub enum Commands {
    /// Config is mostly used for debugging the final config output
    Release {},

    #[command(hide = true)]
    Config {
        #[command(subcommand)]
        command: ConfigCommand,
    },

    #[command(hide = true)]
    Gitea {
        #[command(subcommand)]
        command: GiteaCommand,
    },
    /// Helps you identify missing things from your execution environment for cuddle-please to function as intended
    Doctor {},
}

#[derive(Subcommand, Debug, Clone)]
pub enum ConfigCommand {
    /// List will list the final configuration
    List {},
}

#[derive(Subcommand, Debug, Clone)]
pub enum GiteaCommand {
    Connect {},
    Tags {
        #[command(subcommand)]
        command: Option<GiteaTagsCommand>,
    },
    SinceCommit {
        #[arg(long)]
        sha: String,

        #[arg(long)]
        branch: String,
    },
    CheckPr {},
}

#[derive(Subcommand, Debug, Clone)]
pub enum GiteaTagsCommand {
    MostSignificant {},
}

fn get_current_path(
    optional_current_dir: Option<&Path>,
    optional_source_path: Option<PathBuf>,
) -> anyhow::Result<PathBuf> {
    let path = optional_source_path
        .or_else(|| optional_current_dir.map(|p| p.to_path_buf())) // fall back on current env from environment
        .filter(|v| v.to_string_lossy() != "") // make sure we don't get empty values
        //.and_then(|p| p.canonicalize().ok()) // Make sure we get the absolute path
        //.context("could not find current dir, pass --source as a replacement")?;
        .unwrap_or(PathBuf::from("."));

    if !path.exists() {
        anyhow::bail!("path doesn't exist {}", path.display());
    }

    Ok(path)
}