use std::{
    collections::VecDeque,
    fs::{self, File},
    io::Write as _,
    path::{Path, PathBuf},
    process::Command,
};

use anyhow::{bail, Context, Result};
use cargo::CargoAction;
use clap::ValueEnum;
use esp_metadata::Chip;
use strum::{Display, EnumIter, IntoEnumIterator as _};

use self::cargo::CargoArgsBuilder;

pub mod cargo;

#[derive(
    Debug,
    Clone,
    Copy,
    PartialEq,
    Eq,
    PartialOrd,
    Ord,
    Hash,
    Display,
    EnumIter,
    ValueEnum,
    serde::Serialize,
)]
#[serde(rename_all = "kebab-case")]
#[strum(serialize_all = "kebab-case")]
pub enum Package {
    EspAlloc,
    EspBacktrace,
    EspBuild,
    EspHal,
    EspHalEmbassy,
    EspHalProcmacros,
    EspHalSmartled,
    EspIeee802154,
    EspLpHal,
    EspMetadata,
    EspPrintln,
    EspRiscvRt,
    EspStorage,
    EspWifi,
    Examples,
    HilTest,
    XtensaLx,
    XtensaLxRt,
}

#[derive(Debug, Default, Clone)]
pub struct Metadata {
    example_path: PathBuf,
    chips: Vec<Chip>,
    features: Vec<String>,
}

impl Metadata {
    pub fn new(example_path: &Path, chips: Vec<Chip>, features: Vec<String>) -> Self {
        let chips = if chips.is_empty() {
            Chip::iter().collect()
        } else {
            chips
        };

        Self {
            example_path: example_path.to_path_buf(),
            chips,
            features,
        }
    }

    /// Absolute path to the example.
    pub fn example_path(&self) -> &Path {
        &self.example_path
    }

    /// Name of the example.
    pub fn name(&self) -> String {
        self.example_path()
            .file_name()
            .unwrap()
            .to_string_lossy()
            .replace(".rs", "")
    }

    /// A list of all features required for building a given examples.
    pub fn features(&self) -> &[String] {
        &self.features
    }

    /// If the specified chip is in the list of chips, then it is supported.
    pub fn supports_chip(&self, chip: Chip) -> bool {
        self.chips.contains(&chip)
    }
}

#[derive(Debug, Clone, Copy, Display, ValueEnum)]
#[strum(serialize_all = "lowercase")]
pub enum Version {
    Major,
    Minor,
    Patch,
}

/// Build the documentation for the specified package and device.
pub fn build_documentation(
    workspace: &Path,
    package: Package,
    chip: Chip,
    target: &str,
) -> Result<()> {
    let package_name = package.to_string();
    let package_path = windows_safe_path(&workspace.join(&package_name));

    log::info!("Building '{package_name}' documentation targeting '{chip}'");

    let mut features = vec![chip.to_string()];

    if matches!(package, Package::EspHal) {
        features.push("ci".to_owned())
    }

    // Build up an array of command-line arguments to pass to `cargo`:
    let builder = CargoArgsBuilder::default()
        .subcommand("doc")
        .target(target)
        .features(&features)
        .arg("-Zbuild-std=alloc,core")
        .arg("-Zrustdoc-map")
        .arg("--lib")
        .arg("--no-deps");

    let args = builder.build();
    log::debug!("{args:#?}");

    // Execute `cargo doc` from the package root:
    cargo::run(&args, &package_path)?;

    Ok(())
}

/// Load all examples at the given path, and parse their metadata.
pub fn load_examples(path: &Path) -> Result<Vec<Metadata>> {
    let mut examples = Vec::new();

    for entry in fs::read_dir(path)? {
        let path = windows_safe_path(&entry?.path());
        let text = fs::read_to_string(&path)
            .with_context(|| format!("Could not read {}", path.display()))?;

        let mut chips = Vec::new();
        let mut features = Vec::new();

        // We will indicate metadata lines using the `//%` prefix:
        for line in text.lines().filter(|line| line.starts_with("//%")) {
            let mut split = line
                .trim_start_matches("//%")
                .trim()
                .split_ascii_whitespace()
                .map(|s| s.to_string())
                .collect::<VecDeque<_>>();

            if split.len() < 2 {
                bail!(
                    "Expected at least two elements (key, value), found {}",
                    split.len()
                );
            }

            // The trailing ':' on metadata keys is optional :)
            let key = split.pop_front().unwrap();
            let key = key.trim_end_matches(':');

            if key == "CHIPS" {
                chips = split
                    .iter()
                    .map(|s| Chip::from_str(s, false).unwrap())
                    .collect::<Vec<_>>();
            } else if key == "FEATURES" {
                features = split.into();
            } else {
                log::warn!("Unrecognized metadata key '{key}', ignoring");
            }
        }

        examples.push(Metadata::new(&path, chips, features));
    }

    Ok(examples)
}

/// Run or build the specified test or example for the specified chip.
pub fn execute_app(
    package_path: &Path,
    chip: Chip,
    target: &str,
    app: &Metadata,
    action: CargoAction,
    mut repeat: usize,
) -> Result<()> {
    log::info!(
        "Building example '{}' for '{}'",
        app.example_path().display(),
        chip
    );
    if !app.features().is_empty() {
        log::info!("  Features: {}", app.features().join(","));
    }

    let package = app.example_path().strip_prefix(package_path)?;
    log::info!("Package: {:?}", package);
    let (bin, subcommand) = if action == CargoAction::Build {
        repeat = 1; // Do not repeat builds in a loop
        let bin = if package.starts_with("src/bin") {
            format!("--bin={}", app.name())
        } else if package.starts_with("tests") {
            format!("--test={}", app.name())
        } else {
            format!("--example={}", app.name())
        };
        (bin, "build")
    } else if package.starts_with("src/bin") {
        (format!("--bin={}", app.name()), "run")
    } else if package.starts_with("tests") {
        (format!("--test={}", app.name()), "test")
    } else {
        (format!("--example={}", app.name()), "run")
    };

    let mut features = app.features().to_vec();
    features.push(chip.to_string());

    let mut builder = CargoArgsBuilder::default()
        .subcommand(subcommand)
        .arg("--release")
        .target(target)
        .features(&features)
        .arg(bin);

    if subcommand == "test" && chip == Chip::Esp32c2 {
        builder = builder.arg("--").arg("--speed").arg("15000");
    }

    // If targeting an Xtensa device, we must use the '+esp' toolchain modifier:
    if target.starts_with("xtensa") {
        builder = builder.toolchain("esp");
        builder = builder.arg("-Zbuild-std=core,alloc")
    }

    let args = builder.build();
    log::debug!("{args:#?}");

    for _ in 0..repeat {
        cargo::run(&args, package_path)?;
    }

    Ok(())
}

/// Build the specified package, using the given toolchain/target/features if
/// provided.
pub fn build_package(
    package_path: &Path,
    features: Vec<String>,
    no_default_features: bool,
    toolchain: Option<String>,
    target: Option<String>,
) -> Result<()> {
    log::info!("Building package '{}'", package_path.display());
    if !features.is_empty() {
        log::info!("  Features: {}", features.join(","));
    }
    if let Some(ref target) = target {
        log::info!("  Target:   {}", target);
    }

    let mut builder = CargoArgsBuilder::default()
        .subcommand("build")
        .arg("--release");

    if let Some(toolchain) = toolchain {
        builder = builder.toolchain(toolchain);
    }

    if let Some(target) = target {
        // If targeting an Xtensa device, we must use the '+esp' toolchain modifier:
        if target.starts_with("xtensa") {
            builder = builder.toolchain("esp");
            builder = builder.arg("-Zbuild-std=core,alloc")
        }
        builder = builder.target(target);
    }

    if !features.is_empty() {
        builder = builder.features(&features);
    }

    if no_default_features {
        builder = builder.arg("--no-default-features");
    }

    let args = builder.build();
    log::debug!("{args:#?}");

    cargo::run(&args, package_path)?;

    Ok(())
}

/// Bump the version of the specified package by the specified amount.
pub fn bump_version(workspace: &Path, package: Package, amount: Version) -> Result<()> {
    let manifest_path = workspace.join(package.to_string()).join("Cargo.toml");
    let manifest = fs::read_to_string(&manifest_path)
        .with_context(|| format!("Could not read {}", manifest_path.display()))?;

    let mut manifest = manifest.parse::<toml_edit::DocumentMut>()?;

    let version = manifest["package"]["version"]
        .to_string()
        .trim()
        .trim_matches('"')
        .to_string();
    let prev_version = &version;

    let mut version = semver::Version::parse(&version)?;
    match amount {
        Version::Major => {
            version.major += 1;
            version.minor = 0;
            version.patch = 0;
        }
        Version::Minor => {
            version.minor += 1;
            version.patch = 0;
        }
        Version::Patch => {
            version.patch += 1;
        }
    }

    log::info!("Bumping version for package: {package} ({prev_version} -> {version})");

    manifest["package"]["version"] = toml_edit::value(version.to_string());
    fs::write(manifest_path, manifest.to_string())?;

    Ok(())
}

// File header for the generated eFuse fields.
const EFUSE_FIELDS_RS_HEADER: &str = r#"
//! eFuse fields for the $CHIP.
//!
//! This file was automatically generated, please do not edit it manually!
//!
//! For information on how to regenerate these files, please refer to the
//! `xtask` package's `README.md` file.
//!
//! Generated on:   $DATE
//! ESP-IDF Commit: $HASH

use super::EfuseBlock;
use crate::soc::efuse_field::EfuseField;
"#;

#[derive(Debug, Clone, PartialEq, serde::Deserialize)]
struct EfuseField {
    field_name: String,
    efuse_block: String,
    bit_start: u32,
    bit_count: u32,
    description: String,
}

/// Generate Rust constants for each eFuse field defined in the given CSV file.
pub fn generate_efuse_table(
    chip: &Chip,
    idf_path: impl AsRef<Path>,
    out_path: impl AsRef<Path>,
) -> Result<()> {
    let idf_path = idf_path.as_ref();
    let out_path = out_path.as_ref();

    // We will put the date of generation in the file header:
    let date = chrono::Utc::now().date_naive();

    // Determine the commit (short) hash of the HEAD commit in the
    // provided ESP-IDF repository:
    let output = Command::new("git")
        .args(["rev-parse", "HEAD"])
        .current_dir(idf_path)
        .output()?;
    let idf_hash = String::from_utf8_lossy(&output.stdout[0..=7]).to_string();

    // Read the CSV file containing the eFuse field definitions:
    let csv_path = idf_path
        .join("components")
        .join("efuse")
        .join(chip.to_string())
        .join("esp_efuse_table.csv");

    // Create the reader and writer from our source and destination file paths:
    let mut reader = csv::ReaderBuilder::new()
        .comment(Some(b'#'))
        .has_headers(false)
        .trim(csv::Trim::All)
        .from_path(csv_path)?;
    let mut writer = File::create(out_path)?;

    // Write the header to the destination file:
    writeln!(
        writer,
        "{}",
        EFUSE_FIELDS_RS_HEADER
            .trim_start()
            .replace("$CHIP", chip.pretty_name())
            .replace("$DATE", &date.to_string())
            .replace("$HASH", &idf_hash)
    )?;

    // Build a vector of parsed eFuse fields; we build this vector up first rather
    // than writing directly to the destination file, as we need to do some
    // pre-processing first:
    let mut fields = VecDeque::new();
    for result in reader.deserialize() {
        // We will print a warning and just ignore any fields which cannot be
        // successfull parsed:
        let mut efuse_field: EfuseField = match result {
            Ok(field) => field,
            Err(e) => {
                log::warn!("{e}");
                continue;
            }
        };

        // Remove any comments from the eFuse field descriptions:
        efuse_field.description.truncate(
            if let Some((prefix, _comment)) = efuse_field.description.split_once('#') {
                prefix
            } else {
                &efuse_field.description
            }
            .trim_end()
            .len(),
        );

        // Link to other eFuse fields in documentation, using code blocks:
        efuse_field.description = efuse_field
            .description
            .replace('[', "`[")
            .replace(']', "]`");

        // Convert the eFuse field name into a valid Rust iddentifier:
        efuse_field.field_name = efuse_field.field_name.replace('.', "_");

        // Replace any non-digit characters in the eFuse block:
        efuse_field.efuse_block = efuse_field
            .efuse_block
            .replace(|c: char| !c.is_ascii_digit(), "");

        fields.push_back(efuse_field);
    }

    // Now that we've parsed all eFuse field definitions, we can perform our
    // pre-processing; right now, this just means handling any multi-world
    // fields:
    let mut i = 0;
    while i < fields.len() {
        let field = fields[i].clone();

        if field.field_name.is_empty() {
            let mut prev = fields[i - 1].clone();
            prev.bit_start = field.bit_start;
            prev.bit_count += field.bit_count;
            fields[i - 1] = prev;

            fields.retain(|x| *x != field);
        } else {
            i += 1;
        }
    }

    // Finally, write out each eFuse field definition to the destination file:
    while let Some(EfuseField {
        field_name,
        efuse_block,
        bit_start,
        bit_count,
        description,
    }) = fields.pop_front()
    {
        writeln!(writer, "/// {description}")?;
        writeln!(writer,
            "pub const {field_name}: EfuseField = EfuseField::new(EfuseBlock::Block{efuse_block}, {bit_start}, {bit_count});"
        )?;
    }

    Ok(())
}

// ----------------------------------------------------------------------------
// Helper Functions

/// Return a (sorted) list of paths to each valid Cargo package in the
/// workspace.
pub fn package_paths(workspace: &Path) -> Result<Vec<PathBuf>> {
    let mut paths = Vec::new();
    for entry in fs::read_dir(workspace)? {
        let entry = entry?;
        if entry.file_type()?.is_dir() {
            if entry.path().join("Cargo.toml").exists() {
                paths.push(entry.path());
            }
        }
    }

    paths.sort();

    Ok(paths)
}

/// Parse the version from the specified package's Cargo manifest.
pub fn package_version(workspace: &Path, package: Package) -> Result<semver::Version> {
    #[derive(Debug, serde::Deserialize)]
    pub struct Manifest {
        package: Package,
    }

    #[derive(Debug, serde::Deserialize)]
    pub struct Package {
        version: semver::Version,
    }

    let path = workspace.join(package.to_string()).join("Cargo.toml");
    let path = windows_safe_path(&path);
    let manifest =
        fs::read_to_string(&path).with_context(|| format!("Could not read {}", path.display()))?;
    let manifest: Manifest = basic_toml::from_str(&manifest)?;

    Ok(manifest.package.version)
}

/// Make the path "Windows"-safe
pub fn windows_safe_path(path: &Path) -> PathBuf {
    PathBuf::from(path.to_str().unwrap().to_string().replace("\\\\?\\", ""))
}