rusty-tags 0.8.1

use std::fs::File;
use std::io::Read;
use std::path::{Path, PathBuf};
use toml;

use app_result::{AppResult, app_err_msg};

use types::{
    TagsRoot,
    TagsRoots,
    SourceKind
};

/// Reads the dependencies from the `Cargo.toml` located in `cargo_toml_dir`
pub fn read_dependencies(cargo_toml_dir: &Path) -> AppResult<TagsRoots> {
    let toml_table = {
        let mut cargo_toml = cargo_toml_dir.to_path_buf();
        cargo_toml.push("Cargo.toml");
        try!(parse_toml(&cargo_toml))
    };

    let mut tags_roots: TagsRoots = Vec::new();
    let deps = try!(collect_dependencies(&toml_table));
    if deps.is_empty() {
        tags_roots.push(TagsRoot::Proj { root_dir: cargo_toml_dir.to_path_buf(), dependencies: Vec::new() });
        return Ok(tags_roots);
    }

    let lock_table = {
        let mut cargo_lock = cargo_toml_dir.to_path_buf();
        cargo_lock.push("Cargo.lock");
        try!(parse_toml(&cargo_lock))
    };

    let packages: Vec<&toml::Table> = try!(
        lock_table.get("package")
            .and_then(toml::Value::as_slice)
            .map(|s| {
                s.iter()
                 .filter_map(toml::Value::as_table)
                 .collect()
        })
        .ok_or(app_err_msg(format!("Couldn't get Array of Tables entry for 'package'!")))
    );

    for package in packages.iter() {
        let lib_name = try!(
            package.get("name")
                .and_then(toml::Value::as_str)
                .ok_or_else(|| app_err_msg(format!("Couldn't find name string in package: '{:?}'!", package)))
        );

        let dep_names = try!(get_dependencies(*package));
        let mut dep_src_kinds: Vec<SourceKind> = Vec::new();
        for dep_name in dep_names.iter() {
            let dep_package = try!(find_package(&packages, *dep_name));
            if let Ok(src_kind) = get_source_kind(dep_package, *dep_name) {
                dep_src_kinds.push(src_kind);
            }
        }

        if let Ok(src_kind) = get_source_kind(*package, lib_name) {
            tags_roots.push(TagsRoot::Lib { src_kind: src_kind, dependencies: dep_src_kinds });
        }
    }

    let mut lib_src_kinds: Vec<SourceKind> = Vec::new();
    for (lib_name, value) in deps {
        match *value {
            // handling crates.io dependencies with a version
            toml::Value::String(_) => {
                let pkg = try!(find_package(&packages, lib_name));
                lib_src_kinds.push(try!(get_source_kind(pkg, lib_name)));
            }

            // handling of table dependencies
            toml::Value::Table(ref table) => {
                // handling of local path dependencies
                if let Some(path) = table.get("path") {
                    let mut path = try!(
                        path.as_str().ok_or_else(|| {
                            app_err_msg(format!("Expected a String for 'path' entry in '{}'", value))
                        })
                        .map(PathBuf::from)
                    );

                    if path.is_relative() {
                        let mut abs_path = cargo_toml_dir.to_path_buf();
                        abs_path.push(path);
                        path = abs_path;
                    }

                    lib_src_kinds.push(SourceKind::Path { lib_name: lib_name.clone(), path: path });
                // handling of git and crates.io dependencies (may have additional parameters set:
                // optional, etc.)
                } else if table.get("version").is_some() || table.get("git").is_some() {
                    let pkg = try!(find_package(&packages, lib_name));
                    lib_src_kinds.push(try!(get_source_kind(pkg, lib_name)));
                } else {
                    return Err(app_err_msg(format!("Couldn't find a 'path', 'version' or 'git' attribute for '{}' in '{}'",
                                                   lib_name, value)));
                }
            }

            _ => {
                return Err(app_err_msg(format!("Expected a String or a Table for the dependency with the name '{}', but got: '{}'",
                                               lib_name, value)));
            }
        }
    }

    tags_roots.push(TagsRoot::Proj { root_dir: cargo_toml_dir.to_path_buf(), dependencies: lib_src_kinds });
    Ok(tags_roots)
}

fn get_source_kind(lib_package: &toml::Table, lib_name: &str) -> AppResult<SourceKind> {
    let source = try!(
        lib_package.get("source")
            .and_then(toml::Value::as_str)
            .ok_or_else(|| app_err_msg(format!("Couldn't find source string in package: '{:?}'!", lib_package)))
    );

    let src_type = try!(
        source.split('+')
            .nth(0)
            .ok_or_else(|| app_err_msg(format!("Couldn't find source type in: '{}'!", source)))
    );

    let version = try!(
        lib_package.get("version")
            .and_then(toml::Value::as_str)
            .ok_or_else(|| app_err_msg(format!("Couldn't find version string in package: '{:?}'!", lib_package)))
    );

    match src_type {
        "git" => {
            let commit_hash = try!(
                source.split('#')
                    .last()
                    .ok_or_else(|| app_err_msg(format!("Couldn't find commit hash in source entry: '{}'!", source)))
            );

            Ok(SourceKind::Git { lib_name: lib_name.to_string(), commit_hash: commit_hash.to_string() })
        },

        "registry" => {
            Ok(SourceKind::CratesIo { lib_name: lib_name.to_string(), version: version.to_string() })
        }

        _ => {
            Err(app_err_msg(format!("Unexpected source type '{}' in package: '{:?}'!", src_type, lib_package)))
        }
    }
}

/// the name of a dependency
type DepName = String;

/// Collects all dependencies specified in the `Cargo.toml`. The dependencies might
/// be specified by `dependencies`, `build-dependencies` or `dev-dependencies`.
fn collect_dependencies(cargo_toml: &toml::Table) -> AppResult<Vec<(&DepName, &toml::Value)>> {
    let mut deps = Vec::with_capacity(50);
    for dep_type in &["dependencies", "build-dependencies", "dev-dependencies"] {
        if let Some(deps_value) = cargo_toml.get(*dep_type) {
            let deps_table = try!(
                deps_value.as_table()
                    .ok_or(app_err_msg(format!("Couldn't get toml::Table entry for '{}'! Got a '{}'!", dep_type, deps_value)))
            );

            for dep in deps_table {
                deps.push(dep);
            }
        }
    }

    Ok(deps)
}

fn get_dependencies(lib_package: &toml::Table) -> AppResult<Vec<&str>> {
    let mut dep_names: Vec<&str> = Vec::new();

    if ! lib_package.contains_key("dependencies") {
        return Ok(dep_names);
    }

    let dep_strs: Vec<&str> = try!(
        lib_package.get("dependencies")
            .and_then(toml::Value::as_slice)
            .map(|s| {
                s.iter()
                 .filter_map(toml::Value::as_str)
                 .collect()
        })
        .ok_or_else(|| app_err_msg(format!("Couldn't get Array of Strings for 'dependencies' entry: '{:?}'!", lib_package)))
    );

    for dep_str in dep_strs.iter() {
        let dep_name = try!(
            dep_str.split(' ')
                .nth(0)
                .ok_or_else(|| app_err_msg(format!("Couldn't get name from dependency: '{}'!", dep_str)))
            );

        dep_names.push(dep_name);
    }

    Ok(dep_names)
}

fn find_package<'a>(packages: &'a Vec<&toml::Table>, lib_name: &str) -> AppResult<&'a toml::Table> {
    let package = try!(
        packages.iter()
            .find(|p| p.get("name").and_then(toml::Value::as_str) == Some(lib_name))
            .ok_or_else(|| app_err_msg(format!("Couldn't find package with name = '{}'!", lib_name)))
    );

    Ok(*package)
}

fn parse_toml(path: &Path) -> AppResult<toml::Table> {
    let mut file = try!(File::open(path));
    let mut string = String::new();
    try!(file.read_to_string(&mut string));
    let mut parser = toml::Parser::new(&string);
    parser.parse().ok_or_else(|| app_err_msg(format!("Couldn't parse '{}': {:?}", path.display(), parser.errors)))
}