use std::{fmt::Display, process::Command};

use crate::{config::Config, error::*};

/// Represents a changelog that is currently under construction.
#[derive(Clone, Debug)]
pub struct Changelog {
    git_log: Option<String>,
}

impl Changelog {
    pub fn build(cfg: &Config) -> Result<Self> {
        if !cfg.yaml.changelog.enable {
            return Err(ChangelogError::IsDisabledButUsed.into());
        }
        let git_log = Self::make_git_log(cfg)?;
        Ok(Changelog { git_log })
    }

    fn make_git_log(cfg: &Config) -> Result<Option<String>> {
        if !cfg.yaml.changelog.enable {
            return Ok(None);
        }
        let mut cmd = Command::new("git");
        cmd.arg("log")
            .arg(format!("{}..HEAD", Self::get_last_tag()?,))
            .arg("--oneline");
        let out = cmd.output()?;
        // FIXME: this does not catch fancy colors, those are from the shell as it seems? I don't
        // get it.
        let buf = String::from_utf8(out.stdout).map_err(ChangelogError::GitUTF8Error)?;
        if !out.status.success() {
            // TODO: get the stderr for error reporting
            // TODO: Make the error more understandable for the user
            return Err(ChangelogError::GitBadStatus(out.status, buf).into());
        }

        dbg!(&buf);
        Ok(Some(buf))
    }

    fn get_last_tag() -> Result<String> {
        let mut cmd = Command::new("git");
        cmd.arg("describe").arg("--tags").arg("--abbrev=0");
        let out = cmd.output()?;
        let buf = String::from_utf8(out.stdout).map_err(ChangelogError::GitUTF8Error)?;
        if !out.status.success() {
            // TODO: get the stderr for error reporting
            // TODO: Make the error more understandable for the user
            return Err(ChangelogError::GitBadStatus(out.status, buf).into());
        }
        let buf = buf.replace('\n', "");
        Ok(buf)
    }
}

impl Display for Changelog {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        let mut full: String = String::new();
        full += "Changelog";
        if self.git_log.is_some() {
            full += format!("\n\n{}", self.git_log.clone().unwrap()).as_str();
        }
        write!(f, "{full}")
    }
}