use crate::cfg::config::Config;
use std::{
    fs::create_dir_all,
    path::{Path, PathBuf},
    process::Command,
};

use glob::glob;
use num_cpus;

use super::archive::ArchiveOperations;
use super::types::{Build, BuildSystems, Package};

pub trait BuildOperations {
    fn execute_build(&self, build_meta: &Build) -> Result<(), std::io::Error>;
    fn build(&mut self) -> Result<bool, std::io::Error>;
    fn find_makefile(
        &self,
        build_meta: &Build,
        search_dir: &Path,
    ) -> std::io::Result<Option<PathBuf>>;
    fn run_command(cmd: std::process::Command, context: &str) -> Result<(), std::io::Error>;

    fn run_build_system(
        source_dir: &Path,
        required_file: &str,
        configure_cmd: &[&str],
        build_cmd: &[&str],
        work_dir: &Path,
        envs: &[(String, String)],
        context: &str,
    ) -> Result<(), std::io::Error>;
}

#[allow(dead_code)]
impl BuildOperations for Package {
    /// Runs a command and checks if it was successful.
    /// If the command fails, it returns an error with the command's
    /// stdout and stderr.
    ///
    /// # Arguments
    ///
    /// * `cmd`: The command to run.
    /// * `context`: A string to prefix the error message with if the command fails.
    fn run_command(mut cmd: std::process::Command, context: &str) -> Result<(), std::io::Error> {
        let output = cmd
            .output()
            .map_err(|e| std::io::Error::other(format!("{} failed: {}", context, e)))?;

        if !output.status.success() {
            let stderr = String::from_utf8_lossy(&output.stderr);
            let stdout = String::from_utf8_lossy(&output.stdout);
            return Err(std::io::Error::other(format!(
                "{} failed:\nStdout: {}\nStderr: {}",
                context, stdout, stderr
            )));
        }
        Ok(())
    }

    /// Runs a build system given the following parameters:
    ///
    /// `source_dir`: The directory containing the source code
    /// `required_file`: The file that must exist in the source directory
    /// `configure_cmd`: The command to run for configure step
    /// `build_cmd`: The command to run for build step
    /// `work_dir`: The directory where the build process will take place
    /// `envs`: A list of environment variables to set during the build process
    /// `context`: A string context to provide for error messages
    fn run_build_system(
        source_dir: &Path,
        required_file: &str,
        configure_cmd: &[&str],
        build_cmd: &[&str],
        work_dir: &Path,
        envs: &[(String, String)],
        context: &str,
    ) -> Result<(), std::io::Error> {
        let required_path = source_dir.join(required_file);
        if !required_path.exists() {
            return Err(std::io::Error::other(format!(
                "{} file not found: {}",
                context,
                required_path.display()
            )));
        }

        if !work_dir.exists() {
            create_dir_all(work_dir)?;
        }

        // Configure step
        let mut config_cmd = std::process::Command::new(configure_cmd[0]);
        config_cmd.args(&configure_cmd[1..]).current_dir(source_dir);
        for (key, value) in envs {
            config_cmd.env(key, value);
        }
        log::info!("Running {} configuration: {:?}", context, config_cmd);
        Self::run_command(config_cmd, &format!("{} config", context))?;

        // Build step
        let mut build_cmd_inner = std::process::Command::new(build_cmd[0]);
        build_cmd_inner.args(&build_cmd[1..]).current_dir(work_dir);
        for (key, value) in envs {
            build_cmd_inner.env(key, value);
        }
        log::info!("Running {} build: {:?}", context, build_cmd_inner);
        Self::run_command(build_cmd_inner, &format!("{} build", context))?;

        Ok(())
    }

    /// Finds the build system file (e.g. Makefile, meson.build, CMakeLists.txt, Cargo.toml)
    /// based on the build system specified in the build metadata.
    ///
    /// # Arguments
    ///
    /// * `build_meta`: The build metadata containing the build system type.
    /// * `search_dir`: The directory to search in for the build system file.
    ///
    /// # Returns
    ///
    /// A `Result` containing an `Option<PathBuf>` which is `Some` if the build
    /// system file is found, and `None` otherwise.
    fn find_makefile(
        &self,
        build_meta: &Build,
        search_dir: &Path,
    ) -> std::io::Result<Option<PathBuf>> {
        let (patterns, recursive) = match build_meta.build_system {
            BuildSystems::Make => (vec!["Makefile", "makefile", "GNUmakefile"], false),
            BuildSystems::Meson => (vec!["meson.build", "meson_options.txt"], true),
            BuildSystems::CMake => (vec!["CMakeLists.txt"], true),
            BuildSystems::Cargo => (vec!["Cargo.toml"], false),
        };

        for pattern in &patterns {
            let glob_pattern = if recursive {
                search_dir
                    .join("**")
                    .join(pattern)
                    .to_string_lossy()
                    .into_owned()
            } else {
                search_dir.join(pattern).to_string_lossy().into_owned()
            };

            let entries = glob(&glob_pattern)
                .map_err(|e| std::io::Error::other(format!("Invalid glob pattern: {}", e)))?;

            for entry in entries {
                let path =
                    entry.map_err(|e| std::io::Error::other(format!("Glob error: {}", e)))?;
                return Ok(Some(path));
            }
        }

        Ok(None)
    }

    /// Execute the build script for the package.
    ///
    /// This function takes the `Build` meta information as an argument and
    /// executes the build script accordingly. It also handles the different
    /// build systems supported (Make, CMake, Meson, Cargo).
    ///
    /// # Errors
    ///
    /// Returns an error if the build command fails.
    fn execute_build(&self, build_meta: &Build) -> Result<(), std::io::Error> {
        let config = Config::parse().map_err(|e| std::io::Error::other(e.to_string()))?;
        let build_dir =
            Path::new(&config.paths.cache_dir).join(format!("{}-{}", self.name, self.version));
        if !build_dir.exists() {
            return Err(std::io::Error::other(format!(
                "Build directory not found: {}",
                build_dir.display()
            )));
        }

        let mut cmd_envs: Vec<(String, String)> = Vec::new();
        if let Some(ref env_vars) = build_meta.env {
            for env_line in env_vars.lines() {
                if let Some((key, value)) = env_line.split_once('=') {
                    cmd_envs.push((key.trim().to_string(), value.trim().to_string()));
                }
            }
        }

        if let Some(ref script) = build_meta.script {
            log::info!("Executing custom build script: {}", script);
            Self::validate_custom_script(script)?;
            let mut cmd = if script.starts_with("./") || script.starts_with('/') {
                let script_path = build_dir.join(script);
                if !script_path.exists() {
                    return Err(std::io::Error::other(format!(
                        "Custom script file not found: {}",
                        script_path.display()
                    )));
                }
                let mut inner_cmd = Command::new("/bin/sh");
                inner_cmd.arg("-c");
                inner_cmd.arg(script_path.to_str().unwrap());
                let _ = inner_cmd.output();
                inner_cmd
            } else {
                let mut inner_cmd = Command::new("/bin/sh");
                inner_cmd.arg("-c");
                inner_cmd.arg(script);
                let _ = inner_cmd.output();
                inner_cmd
            };
            cmd.current_dir(&build_dir);
            for (key, value) in &cmd_envs {
                cmd.env(key, value);
            }

            let output = cmd
                .output()
                .map_err(|e| std::io::Error::other(format!("Custom build script failed: {}", e)))?;
            if !output.status.success() {
                let stderr = String::from_utf8_lossy(&output.stderr);
                let stdout = String::from_utf8_lossy(&output.stdout);
                return Err(std::io::Error::other(format!(
                    "Custom build script failed:\nStdout: {}\nStderr: {}",
                    stdout, stderr
                )));
            }
            log::info!(
                "Custom build script completed successfully for package: {}",
                self.name
            );
            return Ok(());
        }

        // No custom script, proceed with build system
        match build_meta.build_system {
            BuildSystems::Make => {
                let found = self
                    .find_makefile(&build_meta, &build_dir)
                    .map_err(|e| {
                        std::io::Error::other(format!("Failed to search for Makefile: {}", e))
                    })?
                    .ok_or_else(|| std::io::Error::other("Makefile not found"))?;

                if !found.exists() {
                    return Err(std::io::Error::other(format!(
                        "Makefile not found: {}",
                        found.display()
                    )));
                }

                let mut cmd = Command::new("make");
                cmd.current_dir(&build_dir);
                cmd.arg("all");
                for (key, value) in &cmd_envs {
                    cmd.env(key, value);
                }
                log::info!("Running Make build: {:?}", cmd);
                Self::run_command(cmd, "Make build")?;
            }
            BuildSystems::CMake => {
                let found = self
                    .find_makefile(&build_meta, &build_dir)
                    .map_err(|e| {
                        std::io::Error::other(format!("Failed to search for CMakeLists: {}", e))
                    })?
                    .ok_or_else(|| std::io::Error::other("Makefile not found"))?;

                if !found.exists() {
                    return Err(std::io::Error::other(format!(
                        "Makefile not found: {}",
                        found.display()
                    )));
                }
                Self::run_build_system(
                    &build_dir,
                    "CMakeLists.txt",
                    &["cmake", "-S", ".", "-B", "build"],
                    &["make", "-j", &num_cpus::get().to_string()],
                    &build_dir.join("build"),
                    &cmd_envs,
                    "CMake",
                )?;
            }
            BuildSystems::Meson => {
                Self::run_build_system(
                    &build_dir,
                    "meson.build",
                    &["meson", "setup", "build"],
                    &["ninja", "-j", &num_cpus::get().to_string()],
                    &build_dir.join("build"),
                    &cmd_envs,
                    "Meson",
                )?;
            }
            BuildSystems::Cargo => {
                Self::run_build_system(
                    &build_dir,
                    "Cargo.toml",
                    &["cargo", "build", "--release"],
                    &[],
                    &build_dir,
                    &cmd_envs,
                    "Cargo",
                )?;
            }
        }

        log::info!("Build completed successfully for package: {}", self.name);
        Ok(())
    }

    /// Builds the package according to the BUILD file in the archive.
    ///
    /// There are two strategies for building the package. If the BUILD file is empty, the package is assumed to be a binary package and the default install hook is skipped. If the BUILD file is not empty, the package is assumed to be a source package and the default build hook is skipped.
    ///
    /// If the BUILD file is empty and the INSTALL file contains a custom script, the custom script is run instead of the default install hook.
    /// If the BUILD file is not empty and the INSTALL file contains a custom script, the custom script is ignored.
    ///
    ///
    /// # Errors
    ///
    /// Returns an error if the BUILD file is invalid or if the build or install hook fails.
    fn build(&mut self) -> Result<bool, std::io::Error> {
        let meta = Self::loadmeta(self)?;
        let install_meta = meta.0;
        // let setts_meta = meta.1;
        let build_meta = meta.2;

        // BUILD NOT EMPTY. SOURCE: -> BUILD -> INSTALL -> SETTS
        // BUILD EMPTY. BIN: -> INSTALL -> SETTS
        enum Strategies {
            Bin,
            Source,
        }

        let strategy; //default

        if build_meta.is_none() {
            log::info!("BUILD file is empty. Skipping build, preparing to install");
            strategy = Strategies::Bin;
        } else {
            strategy = Strategies::Source;
            log::info!("BUILD file is not empty. Skipping install, preparing to build");
        }

        match strategy {
            Strategies::Bin => {
                if install_meta.install.custom_script.is_none() {
                    log::info!("Strategy: BIN; No custom script. Running default install hook.");
                } else {
                    log::info!("Strategy: BIN; Running custom script.");
                    let script = install_meta.install.custom_script.as_ref().unwrap();

                    // Validate script before execution
                    Self::validate_custom_script(script)?;

                    if self.arch.as_str().to_lowercase()
                        != install_meta.package.arch.as_str().to_lowercase()
                    {
                        return Err(std::io::Error::other(format!(
                            "Package arch mismatch. Expected: {}, Actual: {}",
                            install_meta.package.arch.as_str(),
                            self.arch.as_str().to_lowercase()
                        )));
                    }

                    if !script.starts_with("./") {
                        let output = std::process::Command::new(script).output().map_err(|e| {
                            std::io::Error::other(format!("Failed to execute custom script: {}", e))
                        })?;

                        if !output.status.success() {
                            let stderr = String::from_utf8_lossy(&output.stderr);
                            return Err(std::io::Error::other(format!(
                                "Custom script failed:\n{}",
                                stderr
                            )));
                        }
                    } else {
                        let output = std::process::Command::new("/bin/sh")
                            .arg("-c")
                            .arg(script)
                            .output()
                            .map_err(|e| {
                                std::io::Error::other(format!(
                                    "Failed to execute custom script: {}",
                                    e
                                ))
                            })?;

                        if !output.status.success() {
                            let stderr = String::from_utf8_lossy(&output.stderr);
                            return Err(std::io::Error::other(format!(
                                "Custom script failed:\n{}",
                                stderr
                            )));
                        }
                    }
                }
            }

            Strategies::Source => {
                log::info!("Strategy: SOURCE; Running default build hook.");
                if let Err(e) = self.execute_build(&build_meta.unwrap()) {
                    return Err(std::io::Error::other(format!("Build failed: {}", e)));
                }
            }
        }

        Ok(true)
    }
}