use std::{fmt, fs::File, io::Write, path::Path, sync::Arc};

use miden_core::{prettier::PrettyPrint, utils::Serializable};
use midenc_hir_symbol::Symbol;

use crate::{OutputMode, OutputType, Session};

pub trait Emit {
    /// The name of this item, if applicable
    fn name(&self) -> Option<Symbol>;
    /// The output type associated with this item and the given `mode`
    fn output_type(&self, mode: OutputMode) -> OutputType;
    /// Write this item to standard output, inferring the best [OutputMode] based on whether or not
    /// stdout is a tty or not
    fn write_to_stdout(&self, session: &Session) -> std::io::Result<()> {
        let stdout = std::io::stdout().lock();
        let mode = if atty::is(atty::Stream::Stdout) {
            OutputMode::Text
        } else {
            OutputMode::Binary
        };
        self.write_to(stdout, mode, session)
    }
    /// Write this item to the given file path, using `mode` to determine the output type
    fn write_to_file(
        &self,
        path: &Path,
        mode: OutputMode,
        session: &Session,
    ) -> std::io::Result<()> {
        if let Some(dir) = path.parent() {
            std::fs::create_dir_all(dir)?;
        }
        let file = File::create(path)?;
        self.write_to(file, mode, session)
    }
    /// Write this item to the given [std::io::Write] handle, using `mode` to determine the output
    /// type
    fn write_to<W: Write>(
        &self,
        writer: W,
        mode: OutputMode,
        session: &Session,
    ) -> std::io::Result<()>;
}

impl<T: Emit> Emit for Box<T> {
    #[inline]
    fn name(&self) -> Option<Symbol> {
        (**self).name()
    }

    #[inline]
    fn output_type(&self, mode: OutputMode) -> OutputType {
        (**self).output_type(mode)
    }

    #[inline]
    fn write_to_stdout(&self, session: &Session) -> std::io::Result<()> {
        (**self).write_to_stdout(session)
    }

    #[inline]
    fn write_to_file(
        &self,
        path: &Path,
        mode: OutputMode,
        session: &Session,
    ) -> std::io::Result<()> {
        (**self).write_to_file(path, mode, session)
    }

    #[inline]
    fn write_to<W: Write>(
        &self,
        writer: W,
        mode: OutputMode,
        session: &Session,
    ) -> std::io::Result<()> {
        (**self).write_to(writer, mode, session)
    }
}

impl<T: Emit> Emit for Arc<T> {
    #[inline]
    fn name(&self) -> Option<Symbol> {
        (**self).name()
    }

    #[inline]
    fn output_type(&self, mode: OutputMode) -> OutputType {
        (**self).output_type(mode)
    }

    #[inline]
    fn write_to_stdout(&self, session: &Session) -> std::io::Result<()> {
        (**self).write_to_stdout(session)
    }

    #[inline]
    fn write_to_file(
        &self,
        path: &Path,
        mode: OutputMode,
        session: &Session,
    ) -> std::io::Result<()> {
        (**self).write_to_file(path, mode, session)
    }

    #[inline]
    fn write_to<W: Write>(
        &self,
        writer: W,
        mode: OutputMode,
        session: &Session,
    ) -> std::io::Result<()> {
        (**self).write_to(writer, mode, session)
    }
}

impl Emit for miden_assembly::ast::Module {
    fn name(&self) -> Option<Symbol> {
        Some(Symbol::intern(self.path().to_string()))
    }

    fn output_type(&self, _mode: OutputMode) -> OutputType {
        OutputType::Masm
    }

    fn write_to<W: Write>(
        &self,
        mut writer: W,
        mode: OutputMode,
        _session: &Session,
    ) -> std::io::Result<()> {
        assert_eq!(mode, OutputMode::Text, "masm syntax trees do not support binary mode");
        writer.write_fmt(format_args!("{}\n", self))
    }
}

macro_rules! serialize_into {
    ($serializable:ident, $writer:ident) => {
        // NOTE: We're protecting against unwinds here due to i/o errors that will get turned into
        // panics if writing to the underlying file fails. This is because ByteWriter does not have
        // fallible APIs, thus WriteAdapter has to panic if writes fail. This could be fixed, but
        // that has to happen upstream in winterfell
        std::panic::catch_unwind(move || {
            let mut writer = $writer;
            $serializable.write_into(&mut writer)
        })
        .map_err(|p| {
            match p.downcast::<std::io::Error>() {
                // SAFETY: It is guaranteed to be safe to read Box<std::io::Error>
                Ok(err) => unsafe { core::ptr::read(&*err) },
                // Propagate unknown panics
                Err(err) => std::panic::resume_unwind(err),
            }
        })
    };
}

impl Emit for miden_assembly::Library {
    fn name(&self) -> Option<Symbol> {
        None
    }

    fn output_type(&self, mode: OutputMode) -> OutputType {
        match mode {
            OutputMode::Text => OutputType::Mast,
            OutputMode::Binary => OutputType::Masl,
        }
    }

    fn write_to<W: Write>(
        &self,
        mut writer: W,
        mode: OutputMode,
        _session: &Session,
    ) -> std::io::Result<()> {
        struct LibraryTextFormatter<'a>(&'a miden_assembly::Library);
        impl<'a> miden_core::prettier::PrettyPrint for LibraryTextFormatter<'a> {
            fn render(&self) -> miden_core::prettier::Document {
                use miden_core::prettier::*;

                let mast_forest = self.0.mast_forest();
                let mut library_doc = Document::Empty;
                for module_info in self.0.module_infos() {
                    let mut fragments = vec![];
                    for (_, info) in module_info.procedures() {
                        if let Some(proc_node_id) = mast_forest.find_procedure_root(info.digest) {
                            let proc = mast_forest
                                .get_node_by_id(proc_node_id)
                                .expect("malformed mast forest")
                                .to_pretty_print(mast_forest)
                                .render();
                            fragments.push(indent(
                                4,
                                display(format!("procedure {} ({})", &info.name, &info.digest))
                                    + nl()
                                    + proc
                                    + nl()
                                    + const_text("end"),
                            ));
                        }
                    }
                    let module_doc = indent(
                        4,
                        display(format!("module {}", module_info.path()))
                            + nl()
                            + fragments
                                .into_iter()
                                .reduce(|l, r| l + nl() + nl() + r)
                                .unwrap_or_default()
                            + const_text("end"),
                    );
                    if matches!(library_doc, Document::Empty) {
                        library_doc = module_doc;
                    } else {
                        library_doc += nl() + nl() + module_doc;
                    }
                }
                library_doc
            }
        }
        impl<'a> fmt::Display for LibraryTextFormatter<'a> {
            #[inline]
            fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
                self.pretty_print(f)
            }
        }

        match mode {
            OutputMode::Text => writer.write_fmt(format_args!("{}", LibraryTextFormatter(self))),
            OutputMode::Binary => {
                self.write_into(&mut writer);
                Ok(())
            }
        }
    }
}

impl Emit for miden_core::Program {
    fn name(&self) -> Option<Symbol> {
        None
    }

    fn output_type(&self, mode: OutputMode) -> OutputType {
        match mode {
            OutputMode::Text => OutputType::Mast,
            OutputMode::Binary => OutputType::Masl,
        }
    }

    fn write_to_file(
        &self,
        path: &Path,
        mode: OutputMode,
        session: &Session,
    ) -> std::io::Result<()> {
        if let Some(dir) = path.parent() {
            std::fs::create_dir_all(dir)?;
        }
        let mut file = std::fs::File::create(path)?;
        match mode {
            OutputMode::Text => self.write_to(&mut file, mode, session),
            OutputMode::Binary => serialize_into!(self, file),
        }
    }

    fn write_to_stdout(&self, session: &Session) -> std::io::Result<()> {
        let mut stdout = std::io::stdout().lock();
        let mode = if atty::is(atty::Stream::Stdout) {
            OutputMode::Text
        } else {
            OutputMode::Binary
        };
        match mode {
            OutputMode::Text => self.write_to(&mut stdout, mode, session),
            OutputMode::Binary => serialize_into!(self, stdout),
        }
    }

    fn write_to<W: Write>(
        &self,
        mut writer: W,
        mode: OutputMode,
        _session: &Session,
    ) -> std::io::Result<()> {
        match mode {
            OutputMode::Text => writer.write_fmt(format_args!("{}", self)),
            OutputMode::Binary => {
                self.write_into(&mut writer);
                Ok(())
            }
        }
    }
}