//LICENSE Portions Copyright 2019-2021 ZomboDB, LLC.
//LICENSE
//LICENSE Portions Copyright 2021-2023 Technology Concepts & Design, Inc.
//LICENSE
//LICENSE Portions Copyright 2023-2023 PgCentral Foundation, Inc. <contact@pgcentral.org>
//LICENSE
//LICENSE All rights reserved.
//LICENSE
//LICENSE Use of this source code is governed by the MIT license that can be found in the LICENSE file.
use crate::command::stop::stop_postgres;
use crate::command::version::pgrx_default;
use crate::CommandExecute;
use bzip2::bufread::BzDecoder;
use eyre::{eyre, WrapErr};
use owo_colors::OwoColorize;
use pgrx_pg_config::{
    get_c_locale_flags, prefix_path, ConfigToml, PgConfig, PgConfigSelector, Pgrx, PgrxHomeError,
};
use tar::Archive;

use std::collections::HashMap;
use std::fs::File;
use std::io::{Read, Write};
use std::num::NonZeroUsize;
use std::path::{Path, PathBuf};
use std::process::{Command, Stdio};
use std::sync::OnceLock;

static PROCESS_ENV_DENYLIST: &[&str] = &[
    "DEBUG",
    "MAKEFLAGS",
    "MAKELEVEL",
    "MFLAGS",
    "DYLD_FALLBACK_LIBRARY_PATH",
    "OPT_LEVEL",
    "TARGET",
    "PROFILE",
    "OUT_DIR",
    "HOST",
    "NUM_JOBS",
    "LIBRARY_PATH", // see https://github.com/pgcentralfoundation/pgrx/issues/16
];

/// Initialize pgrx development environment for the first time
#[derive(clap::Args, Debug)]
#[clap(author)]
pub(crate) struct Init {
    /// If installed locally, the path to PG12's `pgconfig` tool, or `download` to have pgrx download/compile/install it
    #[clap(env = "PG12_PG_CONFIG", long)]
    pg12: Option<String>,
    /// If installed locally, the path to PG13's `pgconfig` tool, or `download` to have pgrx download/compile/install it
    #[clap(env = "PG13_PG_CONFIG", long)]
    pg13: Option<String>,
    /// If installed locally, the path to PG14's `pgconfig` tool, or `download` to have pgrx download/compile/install it
    #[clap(env = "PG14_PG_CONFIG", long)]
    pg14: Option<String>,
    /// If installed locally, the path to PG15's `pgconfig` tool, or `download` to have pgrx download/compile/install it
    #[clap(env = "PG15_PG_CONFIG", long)]
    pg15: Option<String>,
    /// If installed locally, the path to PG16's `pgconfig` tool, or `download` to have pgrx download/compile/install it
    #[clap(env = "PG16_PG_CONFIG", long)]
    pg16: Option<String>,
    /// If installed locally, the path to PG17's `pgconfig` tool, or `download` to have pgrx download/compile/install it
    #[clap(env = "PG17_PG_CONFIG", long)]
    pg17: Option<String>,
    #[clap(from_global, action = ArgAction::Count)]
    verbose: u8,
    #[clap(long, help = "Base port number")]
    base_port: Option<u16>,
    #[clap(long, help = "Base testing port number")]
    base_testing_port: Option<u16>,
    #[clap(long, help = "Additional flags to pass to the configure script")]
    configure_flag: Vec<String>,
    /// Compile PostgreSQL with the necessary flags to detect a good amount of
    /// memory errors when run under Valgrind.
    ///
    /// Building PostgreSQL with these flags requires that Valgrind be
    /// installed, but the resulting build is usable without valgrind.
    #[clap(long)]
    valgrind: bool,
    #[clap(long, short, help = "Allow N make jobs at once")]
    jobs: Option<usize>,
    #[clap(skip)]
    jobserver: OnceLock<jobslot::Client>,
}

impl CommandExecute for Init {
    #[tracing::instrument(level = "error", skip(self))]
    fn execute(self) -> eyre::Result<()> {
        self.jobserver
            .set(
                jobslot::Client::new(
                    self.jobs
                        .or_else(|| {
                            std::thread::available_parallelism().map(NonZeroUsize::get).ok()
                        })
                        .unwrap_or(1),
                )
                .expect("failed to create jobserver"),
            )
            .unwrap();

        let mut versions = HashMap::new();

        if let Some(ref version) = self.pg12 {
            versions.insert("pg12", version.clone());
        }
        if let Some(ref version) = self.pg13 {
            versions.insert("pg13", version.clone());
        }
        if let Some(ref version) = self.pg14 {
            versions.insert("pg14", version.clone());
        }
        if let Some(ref version) = self.pg15 {
            versions.insert("pg15", version.clone());
        }
        if let Some(ref version) = self.pg16 {
            versions.insert("pg16", version.clone());
        }
        if let Some(ref version) = self.pg17 {
            versions.insert("pg17", version.clone());
        }

        if versions.is_empty() {
            // no arguments specified, so we'll just install our defaults
            init_pgrx(&pgrx_default()?, &self)
        } else {
            // user specified arguments, so we'll only install those versions of Postgres
            let mut default_pgrx = None;
            let mut pgrx = Pgrx::default();

            for (pgver, pg_config_path) in versions {
                let config = if pg_config_path == "download" {
                    if default_pgrx.is_none() {
                        default_pgrx = Some(pgrx_default()?);
                    }
                    default_pgrx
                        .as_ref()
                        .unwrap() // We just set this
                        .get(pgver)
                        .wrap_err_with(|| format!("{pgver} is not a known Postgres version"))?
                        .clone()
                } else {
                    let config = PgConfig::new_with_defaults(pg_config_path.as_str().into());
                    let label = config.label().ok();
                    // We allow None in case it's configured via the environment or something.
                    if label.is_some() && label.as_deref() != Some(pgver) {
                        return Err(eyre!(
                            "wrong `pg_config` given to `--{pgver}` `{pg_config_path:?}` is for PostgreSQL {}",
                            config.major_version()?,
                        ));
                    }
                    config
                };
                pgrx.push(config);
            }

            init_pgrx(&pgrx, &self)
        }
    }
}

#[tracing::instrument(skip_all)]
pub(crate) fn init_pgrx(pgrx: &Pgrx, init: &Init) -> eyre::Result<()> {
    let pgrx_home = match Pgrx::home() {
        Ok(path) => path,
        Err(e) => match e {
            PgrxHomeError::NoHomeDirectory => return Err(e.into()),
            PgrxHomeError::IoError(e) => return Err(e.into()),
            PgrxHomeError::MissingPgrxHome(path) => {
                // $PGRX_HOME doesn't exist, but that's okay as `cargo pgrx init` is the right time
                // to try and create it
                println!("{} PGRX_HOME at `{}`", "     Creating".bold().green(), path.display());
                std::fs::create_dir_all(&path)?;
                path
            }
        },
    };

    let mut output_configs = std::thread::scope(|s| -> eyre::Result<Vec<_>> {
        let span = tracing::Span::current();
        let mut threads = Vec::new();
        // This selector does not necessarily match the support expressed in a project's Cargo.toml
        // the user will template or handwrite. We may wish to check and emit errors then, but we
        // do not require a project at pgrx init time, so permit these oddities for now.
        for pg_config in pgrx.iter(PgConfigSelector::All) {
            let pg_config = pg_config?;
            let span = span.clone();
            let pgrx_home = pgrx_home.clone();
            threads.push(s.spawn(move || {
                let _span = span.entered();
                let mut pg_config = pg_config.clone();
                stop_postgres(&pg_config).ok(); // no need to fail on errors trying to stop postgres while initializing
                if !pg_config.is_real() {
                    pg_config = match download_postgres(&pg_config, &pgrx_home, init) {
                        Ok(pg_config) => pg_config,
                        Err(e) => return Err(eyre!(e)),
                    }
                }

                Ok(pg_config)
            }));
        }

        let mut output_configs = Vec::with_capacity(threads.len());
        for thread in threads {
            let pg_config = thread.join().map_err(|_| eyre!("thread panicked"))??;
            output_configs.push(pg_config);
        }

        Ok(output_configs)
    })?;

    output_configs.sort_by(|a, b| {
        a.major_version()
            .unwrap_or_else(|e| panic!("{e}:  could not determine major version for: `{a:?}`"))
            .cmp(&b.major_version().expect("could not determine major version"))
    });
    for pg_config in output_configs.iter() {
        validate_pg_config(pg_config)?;

        if is_root_user() {
            println!("{} initdb as current user is root user", "   Skipping".bold().green());
        } else {
            let datadir = pg_config.data_dir()?;
            let bindir = pg_config.bin_dir()?;
            if !datadir.try_exists()? {
                initdb(&bindir, &datadir)?;
            }
        }
    }

    write_config(&output_configs, init)?;
    Ok(())
}

#[tracing::instrument(level = "error", skip_all, fields(pg_version = %pg_config.version()?, pgrx_home))]
fn download_postgres(
    pg_config: &PgConfig,
    pgrx_home: &Path,
    init: &Init,
) -> eyre::Result<PgConfig> {
    use crate::command::build_agent_for_url;

    println!(
        "{} Postgres v{} from {}",
        "  Downloading".bold().green(),
        pg_config.version()?,
        pg_config.url().expect("no url"),
    );
    let url = pg_config.url().expect("no url for pg_config").as_str();
    tracing::debug!(url = %url, "Fetching");
    let http_client = build_agent_for_url(url)?;
    let mut http_response = http_client.get(url).call()?;
    let mut buf = Vec::new();
    let _count = http_response.body_mut().as_reader().read_to_end(&mut buf)?;

    let status = http_response.status();
    tracing::trace!(status_code = %status, url = %url, "Fetched");
    if status != 200 {
        return Err(eyre!(
            "Problem downloading {}:\ncode={status}\n{}",
            pg_config.url().unwrap().to_string().yellow().bold(),
            String::from_utf8_lossy(&buf),
        ));
    }

    let pgdir = untar(&buf, pgrx_home, pg_config, init)?;
    configure_postgres(pg_config, &pgdir, init)?;
    make_postgres(pg_config, &pgdir, init)?;
    make_install_postgres(pg_config, &pgdir, init) // returns a new PgConfig object
}

fn untar(bytes: &[u8], pgrxdir: &Path, pg_config: &PgConfig, init: &Init) -> eyre::Result<PathBuf> {
    let _token = init.jobserver.get().unwrap().acquire().unwrap();

    let mut unpackdir = pgrxdir.to_path_buf();
    unpackdir.push(format!("{}_unpack", pg_config.version()?));
    if unpackdir.exists() {
        // delete everything at this path if it already exists
        println!("{} {}", "     Removing".bold().green(), unpackdir.display());
        std::fs::remove_dir_all(&unpackdir)?;
    }
    std::fs::create_dir_all(&unpackdir)?;

    println!(
        "{} Postgres v{} to {}",
        "    Untarring".bold().green(),
        pg_config.version()?,
        unpackdir.display()
    );
    let mut tar_decoder = Archive::new(BzDecoder::new(bytes));
    tar_decoder.unpack(&unpackdir)?;

    let mut pgdir = pgrxdir.to_path_buf();
    pgdir.push(&pg_config.version()?);
    if pgdir.exists() {
        // delete everything at this path if it already exists
        println!("{} {}", "     Removing".bold().green(), pgdir.display());
        std::fs::remove_dir_all(&pgdir)?;
    }

    let first_level_dirs = std::fs::read_dir(&unpackdir)?
        .filter(|entry| {
            entry
                .as_ref()
                .expect("failed to read entry in unpacked dir")
                .metadata()
                .expect("failed to stat entry in unpacked dir")
                .is_dir()
        })
        .collect::<Result<Vec<_>, _>>()?;
    if first_level_dirs.len() != 1 {
        return Err(eyre!(
            "Expected exactly one directory in tarball, found {}",
            first_level_dirs.len()
        ));
    }
    // UNWRAP: length-checked above
    let first_level_dir = first_level_dirs.first().unwrap().path();
    println!(
        "{} {} -> {}",
        "     Renaming".bold().green(),
        first_level_dir.display(),
        pgdir.display()
    );
    std::fs::rename(first_level_dir, &pgdir)?;

    Ok(pgdir)
}

fn fixup_homebrew_for_icu(configure_cmd: &mut Command) {
    // See if it's disabled via an argument
    if configure_cmd.get_args().any(|a| a == "--without-icu") {
        return;
    }
    // Check if the user has manually configured the vars that `./configure`
    // understands.
    // (ideally these vars should be read off of `configure_cmd.get_envs()`
    // before falling back to the system env, but this is involved enough)
    let icu_cflags = std::env::var_os("ICU_CFLAGS").is_some();
    let icu_libs = std::env::var_os("ICU_LIBS").is_some();
    if icu_cflags || icu_libs {
        return;
    }
    // Check if pkg-config knows where they are. (note: `$PKG_CONFIG` is a var
    // respected by `./configure`)
    let pkg_config = std::env::var_os("PKG_CONFIG").unwrap_or_else(|| "pkg-config".into());
    let exists_result =
        Command::new(pkg_config).arg("--exists").arg("\"icu-uc icu-i18n\"").output();
    if exists_result.map(|out| out.status.success()).unwrap_or_default() {
        // pkg-config knows where they are already, so we don't have to do
        // anything.
        return;
    }
    // See if they use homebrew, and have `icu4c` installed.
    let res = Command::new("brew").arg("--prefix").arg("icu4c").output();
    let Ok(output) = res else {
        // They aren't a brew user (or `brew` errored for some other reason), so
        // we can't help them.
        return;
    };
    let icu4c_pkgconfig_path =
        PathBuf::from(String::from_utf8_lossy(&output.stdout).trim()).join("lib").join("pkgconfig");

    if !output.status.success()
        || !icu4c_pkgconfig_path.exists()
        || !icu4c_pkgconfig_path.is_absolute()
    {
        let msg = "\
            Homebrew seems to be in use, but the `icu4c` does not appear to be \
            installed. Without this, the build of PostgreSQL 16 may fail. You \
            may be able to fix this by installing it using:\n\
            \n\
            $ brew install icu4c\n\
            \n\
            before retrying. Alternatively, if you are certain you do not need it \
            you may disable ICU support by invoking `cargo pgrx init` with the \
            `--configure-flags=--without-icu` argument, as follows:\n\
            \n\
            $ cargo pgrx init --configure-flag=--without-icu\n\
            \n\
            However, this is not recommended.\
        ";
        static COMPLAINED: std::sync::Once = std::sync::Once::new();
        COMPLAINED.call_once(|| {
            println!("{}: {msg}", "warning".bold().yellow());
        });
    }
    // Build a new `PKG_CONFIG_PATH`, with our value at the end.
    let mut v = vec![];
    let old = std::env::var_os("PKG_CONFIG_PATH");
    if let Some(old) = old.as_ref() {
        v.extend(std::env::split_paths(old).map(|p| p.to_path_buf()));
    }
    v.push(icu4c_pkgconfig_path);
    let new_var = std::env::join_paths(v).map(|s| s.to_string_lossy().to_string());

    if let Ok(path) = new_var {
        configure_cmd.env("PKG_CONFIG_PATH", path);
    }
}

fn configure_postgres(pg_config: &PgConfig, pgdir: &Path, init: &Init) -> eyre::Result<()> {
    let _token = init.jobserver.get().unwrap().acquire().unwrap();

    println!("{} Postgres v{}", "  Configuring".bold().green(), pg_config.version()?);
    let mut configure_path = pgdir.to_path_buf();
    configure_path.push("configure");
    let mut command = std::process::Command::new(configure_path);
    // Some of these are redundant with `--enable-debug`.
    let mut existing_cppflags = std::env::var("CPPFLAGS").unwrap_or_default();
    existing_cppflags += " -DUSE_ASSERT_CHECKING=1 -DRANDOMIZE_ALLOCATED_MEMORY=1 ";
    if init.valgrind {
        // `USE_VALGRIND` allows valgrind to understand PG's memory context
        // shenanigans. It requires Valgrind be installed (since it causes
        // `postgres` to include a valgrind header), but uses macros which
        // expand to asm statements that ultimately do nothing when valgrind is
        // not connected, so using valgrind is not required even if the build is
        // performed with `-DUSE_VALGRIND`.
        let valgrind_flags = "-DUSE_VALGRIND=1 ";
        existing_cppflags += valgrind_flags;
    }

    command
        .env("CPPFLAGS", existing_cppflags)
        .arg(format!("--prefix={}", get_pg_installdir(pgdir).display()))
        .arg(format!("--with-pgport={}", pg_config.port()?))
        .arg("--enable-debug")
        .arg("--enable-cassert");
    for flag in init.configure_flag.iter() {
        command.arg(flag);
    }
    command
        .stdout(std::process::Stdio::piped())
        .stderr(std::process::Stdio::piped())
        .stdin(std::process::Stdio::null())
        .env("PATH", prefix_path(pgdir))
        .current_dir(pgdir);
    for var in PROCESS_ENV_DENYLIST {
        command.env_remove(var);
    }
    // Work around the fact that pg16 requires icu to be installed and available
    // via pkg-config, but doesn't add it to the pkg-config path. (Does a decent
    // number of checks to try to avoid causing trouble when things were
    // actually fine).
    if cfg!(target_os = "macos") && pg_config.major_version().unwrap_or(0) == 16 {
        fixup_homebrew_for_icu(&mut command);
    }
    let command_str = format!("{command:?}");
    tracing::debug!(command = %command_str, "Running");
    let child = command.spawn()?;
    let output = child.wait_with_output()?;
    tracing::trace!(status_code = %output.status, command = %command_str, "Finished");

    if output.status.success() {
        Ok(())
    } else {
        Err(std::io::Error::other(format!(
            "{}\n{}{}",
            command_str,
            String::from_utf8(output.stdout).unwrap(),
            String::from_utf8(output.stderr).unwrap()
        )))?
    }
}

fn make_postgres(pg_config: &PgConfig, pgdir: &Path, init: &Init) -> eyre::Result<()> {
    println!("{} Postgres v{}", "    Compiling".bold().green(), pg_config.version()?);
    let mut command = std::process::Command::new("make");

    command
        .arg("world-bin")
        .stdout(std::process::Stdio::piped())
        .stderr(std::process::Stdio::piped())
        .stdin(std::process::Stdio::null())
        .current_dir(pgdir);

    for var in PROCESS_ENV_DENYLIST {
        command.env_remove(var);
    }

    let command_str = format!("{command:?}");
    tracing::debug!(command = %command_str, "Running");
    let child = init.jobserver.get().unwrap().configure_and_run(&mut command, |cmd| cmd.spawn())?;
    let output = child.wait_with_output()?;
    tracing::trace!(status_code = %output.status, command = %command_str, "Finished");

    if output.status.success() {
        Ok(())
    } else {
        Err(eyre!(
            "{}\n{}{}",
            command_str,
            String::from_utf8(output.stdout)?,
            String::from_utf8(output.stderr)?
        ))
    }
}

fn make_install_postgres(version: &PgConfig, pgdir: &Path, init: &Init) -> eyre::Result<PgConfig> {
    println!(
        "{} Postgres v{} to {}",
        "   Installing".bold().green(),
        version.version()?,
        get_pg_installdir(pgdir).display()
    );
    let mut command = std::process::Command::new("make");

    command
        .arg("install-world-bin")
        .stdout(std::process::Stdio::piped())
        .stderr(std::process::Stdio::piped())
        .stdin(std::process::Stdio::null())
        .current_dir(pgdir);
    for var in PROCESS_ENV_DENYLIST {
        command.env_remove(var);
    }

    let command_str = format!("{command:?}");
    tracing::debug!(command = %command_str, "Running");
    let child = init.jobserver.get().unwrap().configure_and_run(&mut command, |cmd| cmd.spawn())?;
    let output = child.wait_with_output()?;
    tracing::trace!(status_code = %output.status, command = %command_str, "Finished");

    if output.status.success() {
        let mut pg_config = get_pg_installdir(pgdir);
        pg_config.push("bin");
        pg_config.push("pg_config");
        Ok(PgConfig::new_with_defaults(pg_config))
    } else {
        Err(eyre!(
            "{}\n{}{}",
            command_str,
            String::from_utf8(output.stdout).unwrap(),
            String::from_utf8(output.stderr).unwrap()
        ))
    }
}

fn validate_pg_config(pg_config: &PgConfig) -> eyre::Result<()> {
    println!(
        "{} {}",
        "   Validating".bold().green(),
        pg_config.path().expect("no path for pg_config").display()
    );

    pg_config.includedir_server()?;
    pg_config.pkglibdir()?;
    Ok(())
}

fn write_config(pg_configs: &Vec<PgConfig>, init: &Init) -> eyre::Result<()> {
    let config_path = Pgrx::config_toml()?;
    let mut config = match std::fs::read_to_string(&config_path) {
        Ok(file) => toml::from_str::<ConfigToml>(&file)?,
        Err(e) => {
            if e.kind() == std::io::ErrorKind::NotFound {
                ConfigToml::default()
            } else {
                Err(e)?
            }
        }
    };

    config.base_port = init.base_port;
    config.base_testing_port = init.base_testing_port;
    for pg_config in pg_configs {
        config
            .configs
            .insert(pg_config.label()?, pg_config.path().ok_or(eyre!("no path for pg_config"))?);
    }

    let mut file = File::create(&config_path)?;
    file.write_all(toml::to_string(&config)?.as_bytes())?;

    Ok(())
}

fn get_pg_installdir(pgdir: &Path) -> PathBuf {
    let mut dir = pgdir.to_path_buf();
    dir.push("pgrx-install");
    dir
}

#[cfg(unix)]
fn is_root_user() -> bool {
    // SAFETY: No, the `nix` crate does not do anything more clever:
    // check if effective user ID is 0, AKA "root"
    unsafe { libc::geteuid() == 0 }
}

/// Incorrectly answers false, reverting pgrx to pre-root-aware behavior,
/// which is likely incorrect even if the system lacks "root" semantics.
#[cfg(not(unix))]
fn is_root_user() -> bool {
    false
}

pub(crate) fn initdb(bindir: &Path, datadir: &Path) -> eyre::Result<()> {
    println!(" {} data directory at {}", "Initializing".bold().green(), datadir.display());
    let mut command = std::process::Command::new(format!("{}/initdb", bindir.display()));
    command
        .stdout(Stdio::piped())
        .stderr(Stdio::piped())
        .args(get_c_locale_flags())
        .arg("-D")
        .arg(datadir);

    let command_str = format!("{command:?}");
    tracing::debug!(command = %command_str, "Running");

    let output = command.output().wrap_err_with(|| eyre!("unable to execute: {command_str}"))?;
    tracing::trace!(command = %command_str, status_code = %output.status, "Finished");

    if !output.status.success() {
        return Err(eyre!(
            "problem running initdb: {}\n{}",
            command_str,
            String::from_utf8(output.stderr).unwrap()
        ));
    }

    Ok(())
}
