langcodec-cli 0.12.0

use crate::formats::parse_custom_format;
use crate::transformers::custom_format_to_resource;
use crate::ui;

use langcodec::{Codec, ReadOptions, converter};
use rayon::prelude::*;

/// Strategy for handling conflicts when merging localization files.
#[derive(Debug, Clone, PartialEq, clap::ValueEnum)]
pub enum ConflictStrategy {
    /// Keep the first occurrence of a key
    First,
    /// Keep the last occurrence of a key (default)
    Last,
    /// Skip conflicting entries
    Skip,
}

fn resolve_merge_output_format(
    output: &str,
    lang: Option<&String>,
) -> Result<langcodec::FormatType, String> {
    let mut output_format = converter::infer_format_from_path(output)
        .ok_or_else(|| format!("Cannot infer format from output path: {}", output))?;

    let path_language = match &output_format {
        langcodec::FormatType::Strings(Some(language))
        | langcodec::FormatType::AndroidStrings(Some(language)) => Some(language.clone()),
        _ => None,
    };

    match &output_format {
        langcodec::FormatType::Strings(_) | langcodec::FormatType::AndroidStrings(_) => {
            if let Some(language) = lang {
                if let Some(path_language) = path_language
                    && path_language != *language
                {
                    return Err(format!(
                        "--lang '{}' conflicts with language '{}' implied by output path '{}'",
                        language, path_language, output
                    ));
                }
                output_format = output_format.with_language(Some(language.clone()));
            }
            Ok(output_format)
        }
        langcodec::FormatType::Xliff(_) => Err(
            ".xliff is not supported by `merge` in v1. Use `convert` for XLIFF generation."
                .to_string(),
        ),
        langcodec::FormatType::Xcstrings
        | langcodec::FormatType::CSV
        | langcodec::FormatType::TSV => Ok(output_format),
    }
}

/// Run the merge command: merge multiple localization files into one output file.
pub fn run_merge_command(
    inputs: Vec<String>,
    output: String,
    strategy: ConflictStrategy,
    lang: Option<String>,
    source_language_override: Option<String>,
    version_override: Option<String>,
    strict: bool,
) {
    if inputs.is_empty() {
        eprintln!(
            "{}",
            ui::status_line_stderr(
                ui::Tone::Error,
                "Error: At least one input file is required."
            )
        );
        std::process::exit(1);
    }

    // Read all input files concurrently into Codecs, then combine and merge
    println!(
        "{}",
        ui::status_line_stdout(
            ui::Tone::Info,
            &format!("Reading {} input files...", inputs.len()),
        )
    );
    let read_results: Vec<Result<Codec, String>> = inputs
        .par_iter()
        .map(|input| read_input_to_codec(input, lang.clone(), strict))
        .collect();

    let mut input_codecs: Vec<Codec> = Vec::with_capacity(read_results.len());
    for (idx, res) in read_results.into_iter().enumerate() {
        match res {
            Ok(c) => input_codecs.push(c),
            Err(e) => {
                println!(
                    "{}",
                    ui::status_line_stdout(
                        ui::Tone::Error,
                        &format!("Error reading input file {}/{}", idx + 1, inputs.len()),
                    )
                );
                eprintln!("{}", e);
                std::process::exit(1);
            }
        }
    }

    // Combine all input codecs first, then merge by language
    let mut codec = Codec::from_codecs(input_codecs);

    // Skip validation for merge operations since we expect multiple resources with potentially duplicate languages

    // Merge resources using the new lib crate method
    println!(
        "{}",
        ui::status_line_stdout(ui::Tone::Info, "Merging resources...")
    );
    let conflict_strategy = match strategy {
        ConflictStrategy::First => langcodec::types::ConflictStrategy::First,
        ConflictStrategy::Last => langcodec::types::ConflictStrategy::Last,
        ConflictStrategy::Skip => langcodec::types::ConflictStrategy::Skip,
    };

    let merge_count = codec.merge_resources(&conflict_strategy);
    println!(
        "{}",
        ui::status_line_stdout(
            ui::Tone::Success,
            &format!("Merged {} language groups", merge_count),
        )
    );

    println!(
        "{}",
        ui::status_line_stdout(ui::Tone::Info, "Writing merged output...")
    );
    match resolve_merge_output_format(&output, lang.as_ref()) {
        Ok(format) => {
            println!(
                "{}",
                ui::status_line_stdout(
                    ui::Tone::Info,
                    &format!("Converting resources to format: {:?}", format),
                )
            );
            // Set source_language field in the resources to make sure xcstrings format would not throw an error
            // First, try to get the source language from the first resource if it exists; otherwise, the first resource's language
            // would be used as the source language. If the two checks fail, the default value "en" would be used.
            let source_language = source_language_override
                .filter(|s| !s.trim().is_empty())
                .unwrap_or_else(|| {
                    codec
                        .resources
                        .first()
                        .and_then(|r| {
                            r.metadata
                                .custom
                                .get("source_language")
                                .cloned()
                                .filter(|s| !s.trim().is_empty())
                        })
                        .unwrap_or_else(|| {
                            codec
                                .resources
                                .first()
                                .map(|r| r.metadata.language.clone())
                                .unwrap_or("en".to_string())
                        })
                });

            println!(
                "{}",
                ui::status_line_stdout(
                    ui::Tone::Accent,
                    &format!("Setting metadata.source_language to: {}", source_language),
                )
            );

            // Set version field in the resources to make sure xcstrings format would not throw an error
            let version = version_override.unwrap_or_else(|| {
                codec
                    .resources
                    .first()
                    .and_then(|r| r.metadata.custom.get("version").cloned())
                    .unwrap_or_else(|| "1.0".to_string())
            });

            println!(
                "{}",
                ui::status_line_stdout(
                    ui::Tone::Accent,
                    &format!("Setting metadata.version to: {}", version),
                )
            );

            codec.iter_mut().for_each(|r| {
                r.metadata
                    .custom
                    .insert("source_language".to_string(), source_language.clone());
                r.metadata
                    .custom
                    .insert("version".to_string(), version.clone());
            });

            if let Err(e) = converter::convert_resources_to_format(codec.resources, &output, format)
            {
                println!(
                    "{}",
                    ui::status_line_stdout(ui::Tone::Error, "Error converting resources to format")
                );
                eprintln!("Error converting to {}: {}", output, e);
                std::process::exit(1);
            }
        }
        Err(e) => {
            println!(
                "{}",
                ui::status_line_stdout(ui::Tone::Error, "Error writing output file")
            );
            eprintln!("Error writing to {}: {}", output, e);
            std::process::exit(1);
        }
    }

    println!(
        "{}",
        ui::status_line_stdout(
            ui::Tone::Success,
            &format!("Successfully merged {} files into {}", inputs.len(), output),
        )
    );
}

/// Read a single input file into a vector of Resources, supporting both standard and custom formats
fn read_input_to_resources(
    input: &str,
    lang: Option<String>,
    strict: bool,
) -> Result<Vec<langcodec::Resource>, String> {
    if strict {
        if input.ends_with(".json") || input.ends_with(".yaml") || input.ends_with(".yml") {
            crate::validation::validate_custom_format_file(input)
                .map_err(|e| format!("Failed to validate {}: {}", input, e))?;

            let file_content = std::fs::read_to_string(input)
                .map_err(|e| format!("Error reading file {}: {}", input, e))?;

            crate::formats::validate_custom_format_content(input, &file_content)
                .map_err(|e| format!("Invalid custom format {}: {}", input, e))?;

            let resources = custom_format_to_resource(
                input.to_string(),
                parse_custom_format("json-language-map")
                    .map_err(|e| format!("Failed to parse custom format: {}", e))?,
            )
            .map_err(|e| format!("Failed to convert custom format {}: {}", input, e))?;

            return Ok(resources);
        }

        let mut local_codec = Codec::new();
        local_codec
            .read_file_by_extension_with_options(
                input,
                &ReadOptions::new()
                    .with_language_hint(lang)
                    .with_strict(true),
            )
            .map_err(|e| format!("Error reading {}: {}", input, e))?;
        return Ok(local_codec.resources);
    }

    // Try standard format via lib crate (uses extension + language inference)
    {
        let mut local_codec = Codec::new();
        if let Ok(()) = local_codec.read_file_by_extension(input, lang.clone()) {
            return Ok(local_codec.resources);
        }
    }

    // Try custom JSON/YAML formats (for merge, we follow the existing JSON-language-map behavior)
    if input.ends_with(".json") || input.ends_with(".yaml") || input.ends_with(".yml") {
        // Validate custom format file
        crate::validation::validate_custom_format_file(input)
            .map_err(|e| format!("Failed to validate {}: {}", input, e))?;

        // Auto-detect format based on file content
        let file_content = std::fs::read_to_string(input)
            .map_err(|e| format!("Error reading file {}: {}", input, e))?;

        // Validate file content (ignore returned format; keep parity with existing merge behavior)
        crate::formats::validate_custom_format_content(input, &file_content)
            .map_err(|e| format!("Invalid custom format {}: {}", input, e))?;

        // Convert custom format to Resource using JSON language map to match current merge behavior
        let resources = custom_format_to_resource(
            input.to_string(),
            parse_custom_format("json-language-map")
                .map_err(|e| format!("Failed to parse custom format: {}", e))?,
        )
        .map_err(|e| format!("Failed to convert custom format {}: {}", input, e))?;

        return Ok(resources);
    }

    Err(format!("Error reading {}: unsupported format", input))
}

/// Read a single input into a Codec (wrapper over read_input_to_resources)
fn read_input_to_codec(input: &str, lang: Option<String>, strict: bool) -> Result<Codec, String> {
    let resources = read_input_to_resources(input, lang, strict)?;
    Ok(Codec { resources })
}