// SPDX-License-Identifier: Apache-2.0
// SPDX-FileCopyrightText: 2021 The Gleam contributors

use camino::{Utf8Path, Utf8PathBuf};
use std::fmt::Write as _;

use gleam_core::{
    Error, Result,
    error::{FileIoAction, FileKind},
    paths::ProjectPaths,
};
use hexpm::version::{Identifier, Version};

use crate::{
    cli,
    dependencies::{self, parse_gleam_add_specifier},
    fs,
};

pub fn command(paths: &ProjectPaths, packages_to_add: Vec<String>, dev: bool) -> Result<()> {
    let config = crate::config::root_config(paths)?;
    if packages_to_add.iter().any(|name| name == &config.name) {
        return Err(Error::CannotAddSelfAsDependency { name: config.name });
    }

    let mut new_package_requirements = Vec::with_capacity(packages_to_add.len());
    for specifier in packages_to_add {
        new_package_requirements.push(parse_gleam_add_specifier(&specifier)?);
    }

    // Insert the new packages into the manifest and perform dependency
    // resolution to determine suitable versions
    let manifest = dependencies::resolve_and_download(
        paths,
        cli::Reporter::new(),
        Some((new_package_requirements.clone(), dev)),
        Vec::new(),
        dependencies::DependencyManagerConfig {
            use_manifest: dependencies::UseManifest::Yes,
            check_major_versions: dependencies::CheckMajorVersions::No,
        },
    )?;

    // Read gleam.toml and manifest.toml so we can insert new deps into it
    let mut gleam_toml = read_toml_edit(&paths.root_config())?;
    let mut manifest_toml = read_toml_edit(&paths.manifest())?;

    // Insert the new deps
    for (added_package, _) in new_package_requirements {
        let added_package = added_package.to_string();

        // Pull the selected version out of the new manifest so we know what it is
        let version = &manifest
            .packages
            .iter()
            .find(|package| package.name == *added_package)
            .expect("Added package not found in resolved manifest")
            .version;

        tracing::info!(version=%version, "new_package_version_resolved");

        // Produce a version requirement locked to the major version.
        // i.e. if 1.2.3 is selected we want >= 1.2.3 and < 2.0.0
        let range = format!(
            ">= {} and < {}.0.0",
            version_to_string(version),
            version.major + 1
        );

        // False positive. This package doesn't use the indexing API correctly.
        #[allow(clippy::indexing_slicing)]
        {
            if dev {
                let canonical_name = "dev_dependencies";
                let deprecated_name = "dev-dependencies";
                let has_canonical = gleam_toml.as_table().contains_key(canonical_name);
                let has_deprecated = gleam_toml.as_table().contains_key(deprecated_name);
                if !has_canonical && !has_deprecated {
                    gleam_toml["dev_dependencies"] = toml_edit::table();
                }
                let name = if has_deprecated {
                    deprecated_name
                } else {
                    canonical_name
                };
                gleam_toml[name][&added_package] = toml_edit::value(range.clone());
            } else {
                if !gleam_toml.as_table().contains_key("dependencies") {
                    gleam_toml["dependencies"] = toml_edit::table();
                }
                gleam_toml["dependencies"][&added_package] = toml_edit::value(range.clone());
            }
            manifest_toml["requirements"][&added_package]["version"] = range.into();
        }
    }

    // Write the updated config
    fs::write(&paths.root_config(), &gleam_toml.to_string())?;
    fs::write(&paths.manifest(), &manifest_toml.to_string())?;

    Ok(())
}

fn read_toml_edit(name: &Utf8Path) -> Result<toml_edit::DocumentMut, Error> {
    fs::read(name)?
        .parse::<toml_edit::DocumentMut>()
        .map_err(|e| Error::FileIo {
            kind: FileKind::File,
            action: FileIoAction::Parse,
            path: Utf8PathBuf::from("gleam.toml"),
            err: Some(e.to_string()),
        })
}

fn version_to_string(version: &Version) -> String {
    let mut text = String::new();
    write!(
        text,
        "{}.{}.{}",
        version.major, version.minor, version.patch
    )
    .expect("write to a string");

    if !version.pre.is_empty() {
        text.push('-');
        for (i, identifier) in version.pre.iter().enumerate() {
            if i != 0 {
                text.push('.');
            }
            match *identifier {
                Identifier::Numeric(ref id) => text.push_str(&id.to_string()),
                Identifier::AlphaNumeric(ref id) => text.push_str(id),
            }
        }
    }
    if let Some(build) = version.build.as_ref() {
        text.push('+');
        text.push_str(build);
    }
    text
}

#[test]
fn displays_simple_version_correctly() {
    let version = Version {
        major: 1,
        minor: 23,
        patch: 4,
        pre: vec![],
        build: None,
    };

    let displayed = version_to_string(&version);

    assert_eq!(displayed, "1.23.4");
}

#[test]
fn displays_full_version_correctly() {
    let version = Version {
        major: 1,
        minor: 23,
        patch: 4,
        pre: vec![
            Identifier::Numeric(123),
            Identifier::AlphaNumeric("123abc".to_string()),
        ],
        build: Some("12345abc".to_string()),
    };

    let displayed = version_to_string(&version);

    assert_eq!(displayed, "1.23.4-123.123abc+12345abc");
}