patchloom 0.1.4

use crate::backup::BackupSession;
use crate::cli::global::GlobalFlags;
use crate::diff::{DiffResult, format_diff_result_colored, unified_diff};
use crate::exit;
use crate::write::{atomic_create_new, atomic_write, policy_from_flags};
use anyhow::bail;
use clap::Args;
use serde::Serialize;
use std::fs;

#[derive(Debug, Args)]
#[command(after_help = "\
EXAMPLES:
  patchloom create src/config.json --content '{\"version\": 1}' --apply
  echo 'hello' | patchloom create greeting.txt --stdin --apply")]
pub struct CreateArgs {
    /// Path of the file to create.
    pub file: String,
    /// Content to write (alternative to --stdin).
    #[arg(long)]
    pub content: Option<String>,
    // ref:create-mode:stdin
    /// Read content from stdin.
    #[arg(long)]
    pub stdin: bool,
    // ref:create-mode:force
    /// Overwrite if file already exists.
    #[arg(long)]
    pub force: bool,
    #[command(flatten)]
    pub write: crate::cli::global::WriteFlags,
}

#[derive(Debug, Serialize)]
struct CreateOutput {
    ok: bool,
    path: String,
    #[serde(skip_serializing_if = "Option::is_none")]
    diff: Option<String>,
    #[serde(skip_serializing_if = "Option::is_none")]
    applied: Option<bool>,
}

fn make_diff_output(path: &str, content: &str, color: bool) -> String {
    let diff = unified_diff(path, "", content);
    let total_files_changed = usize::from(diff.has_changes);
    let diff_result = DiffResult {
        diffs: vec![diff],
        total_files_changed,
    };
    format_diff_result_colored(&diff_result, color)
}

fn create_with_backup(
    path: &std::path::Path,
    content: &str,
    force: bool,
    cwd: &std::path::Path,
    policy: &crate::write::WritePolicy,
) -> anyhow::Result<()> {
    let mut backup = BackupSession::new(cwd)?;
    backup.save_before_write(path)?;
    if force {
        atomic_write(path, content, policy)?;
    } else {
        atomic_create_new(path, content, policy)?;
    }
    backup.finalize()?;
    Ok(())
}

/// Create a file, without writing to stdout.
/// Used by the MCP server for direct in-process file creation.
#[cfg(feature = "mcp")]
pub(crate) fn apply_create(
    path: &std::path::Path,
    content: &str,
    force: bool,
) -> anyhow::Result<()> {
    if path.exists() && !path.is_file() {
        bail!("target is not a file: {}", path.display());
    }

    // Ensure parent directories exist.
    if let Some(parent) = path.parent()
        && !parent.as_os_str().is_empty()
    {
        fs::create_dir_all(parent)?;
    }

    let policy = crate::write::WritePolicy::default();
    if force {
        atomic_write(path, content, &policy)?;
    } else {
        atomic_create_new(path, content, &policy)?;
    }
    Ok(())
}

pub fn run(args: CreateArgs, global: &GlobalFlags) -> anyhow::Result<u8> {
    let cwd = global.resolve_cwd()?;

    if args.content.is_some() && args.stdin {
        bail!("--content and --stdin cannot be combined");
    }

    // Resolve content from --content or --stdin.
    let content = if let Some(ref c) = args.content {
        c.clone()
    } else if args.stdin {
        std::io::read_to_string(std::io::stdin())?
    } else {
        bail!("either --content or --stdin must be provided");
    };

    let path = cwd.join(&args.file);

    if path.exists() && !path.is_file() {
        bail!("target is not a file: {}", args.file);
    }

    // For non-write modes, an early exists check is fine (no TOCTOU concern).
    // The --apply path below uses File::create_new for race-free creation.
    if !global.apply && !global.confirm && !args.force && path.exists() {
        bail!("file already exists: {}", args.file);
    }

    // --check mode: report that file would be created.
    // Parent directory creation is handled transparently by --apply,
    // so --check does not reject missing parents.
    if global.check {
        let output = CreateOutput {
            ok: true,
            path: args.file.clone(),
            diff: None,
            applied: None,
        };
        if !global.emit_json(&output)? && !global.quiet {
            println!("would create {}", args.file);
        }
        return Ok(exit::CHANGES_DETECTED);
    }

    // --apply mode: write file.
    if global.apply {
        let policy = policy_from_flags(global, Some(&path));

        // Ensure parent directories exist.
        if let Some(parent) = path.parent()
            && !parent.as_os_str().is_empty()
        {
            fs::create_dir_all(parent)?;
        }

        create_with_backup(&path, &content, args.force, &cwd, &policy)?;

        let diff_text = if global.diff {
            Some(make_diff_output(&args.file, &content, false))
        } else {
            None
        };
        let output = CreateOutput {
            ok: true,
            path: args.file.clone(),
            diff: diff_text,
            applied: None,
        };
        if !global.emit_json(&output)? {
            if global.diff {
                print!(
                    "{}",
                    make_diff_output(&args.file, &content, global.should_color())
                );
            } else if !global.quiet {
                println!("created {}", args.file);
            }
        }
        return Ok(exit::SUCCESS);
    }

    // Default / --diff mode: show unified diff of changes.
    let diff_text = make_diff_output(&args.file, &content, false);

    if global.confirm && (global.json || global.jsonl) {
        let applied = global.should_apply();
        if applied {
            let policy = policy_from_flags(global, Some(&path));
            if let Some(parent) = path.parent()
                && !parent.as_os_str().is_empty()
            {
                fs::create_dir_all(parent)?;
            }
            create_with_backup(&path, &content, args.force, &cwd, &policy)?;
        }
        let output = CreateOutput {
            ok: true,
            path: args.file.clone(),
            diff: Some(diff_text),
            applied: Some(applied),
        };
        global.emit_json(&output)?;
        return Ok(exit::SUCCESS);
    }

    let output = CreateOutput {
        ok: true,
        path: args.file.clone(),
        diff: Some(diff_text),
        applied: None,
    };
    if !global.emit_json(&output)? {
        print!(
            "{}",
            make_diff_output(&args.file, &content, global.should_color())
        );
    }

    // --confirm: prompt after showing diff, then apply if confirmed.
    if global.should_apply() {
        let policy = policy_from_flags(global, Some(&path));
        if let Some(parent) = path.parent()
            && !parent.as_os_str().is_empty()
        {
            fs::create_dir_all(parent)?;
        }
        create_with_backup(&path, &content, args.force, &cwd, &policy)?;
    }

    Ok(exit::SUCCESS)
}

#[cfg(test)]
mod tests {
    use super::*;
    use std::fs;
    use tempfile::TempDir;

    fn default_global() -> GlobalFlags {
        GlobalFlags::default()
    }

    #[test]
    fn create_writes_file_with_correct_content() {
        let dir = TempDir::new().unwrap();
        let file = dir.path().join("new.txt");

        let args = CreateArgs {
            file: file.to_string_lossy().into_owned(),
            content: Some("hello world\n".to_string()),
            stdin: false,
            force: false,
            write: Default::default(),
        };
        let mut global = default_global();
        global.apply = true;

        let code = run(args, &global).unwrap();
        assert_eq!(code, exit::SUCCESS);

        let content = fs::read_to_string(&file).unwrap();
        assert_eq!(content, "hello world\n");
    }

    #[test]
    fn create_refuses_to_overwrite_existing_file_without_force() {
        let dir = TempDir::new().unwrap();
        let file = dir.path().join("existing.txt");
        fs::write(&file, "original\n").unwrap();

        let args = CreateArgs {
            file: file.to_string_lossy().into_owned(),
            content: Some("new content\n".to_string()),
            stdin: false,
            force: false,
            write: Default::default(),
        };
        let mut global = default_global();
        global.apply = true;

        let err = run(args, &global).unwrap_err();
        assert!(err.to_string().contains("file already exists:"));

        // Original content should be unchanged.
        let content = fs::read_to_string(&file).unwrap();
        assert_eq!(content, "original\n");
    }

    #[test]
    fn create_with_force_overwrites_existing_file() {
        let dir = TempDir::new().unwrap();
        let file = dir.path().join("existing.txt");
        fs::write(&file, "original\n").unwrap();

        let args = CreateArgs {
            file: file.to_string_lossy().into_owned(),
            content: Some("overwritten\n".to_string()),
            stdin: false,
            force: true,
            write: Default::default(),
        };
        let mut global = default_global();
        global.apply = true;

        let code = run(args, &global).unwrap();
        assert_eq!(code, exit::SUCCESS);

        let content = fs::read_to_string(&file).unwrap();
        assert_eq!(content, "overwritten\n");
    }

    #[test]
    fn create_rejects_directory_target_even_with_force() {
        let dir = TempDir::new().unwrap();
        let target = dir.path().join("folder");
        fs::create_dir(&target).unwrap();

        let args = CreateArgs {
            file: target.to_string_lossy().into_owned(),
            content: Some("hello\n".to_string()),
            stdin: false,
            force: true,
            write: Default::default(),
        };

        let err = run(args, &default_global()).unwrap_err();
        assert!(err.to_string().contains("target is not a file"));
    }

    #[test]
    fn create_with_check_returns_exit_2() {
        let dir = TempDir::new().unwrap();
        let file = dir.path().join("check.txt");

        let args = CreateArgs {
            file: file.to_string_lossy().into_owned(),
            content: Some("content\n".to_string()),
            stdin: false,
            force: false,
            write: Default::default(),
        };
        let mut global = default_global();
        global.check = true;

        let code = run(args, &global).unwrap();
        assert_eq!(code, exit::CHANGES_DETECTED);

        // File should NOT have been created.
        assert!(!file.exists());
    }

    #[test]
    fn create_default_mode_shows_diff() {
        let dir = TempDir::new().unwrap();
        let file = dir.path().join("diff_preview.txt");

        let args = CreateArgs {
            file: file.to_string_lossy().into_owned(),
            content: Some("hello world\n".to_string()),
            stdin: false,
            force: false,
            write: Default::default(),
        };
        // Default mode: no --apply, no --check.
        let global = default_global();

        let code = run(args, &global).unwrap();
        assert_eq!(code, exit::SUCCESS);

        // File should NOT be created in default diff-preview mode.
        assert!(!file.exists());
    }

    #[test]
    fn create_with_no_content_source_returns_error() {
        let dir = TempDir::new().unwrap();
        let file = dir.path().join("no_content.txt");

        let args = CreateArgs {
            file: file.to_string_lossy().into_owned(),
            content: None,
            stdin: false,
            force: false,
            write: Default::default(),
        };
        let global = default_global();

        let err = run(args, &global).unwrap_err();
        assert!(err.to_string().contains("--content or --stdin"));
    }

    #[test]
    fn create_apply_creates_backup_session() {
        let dir = TempDir::new().unwrap();
        let file = dir.path().join("new.txt");

        let args = CreateArgs {
            file: file.to_string_lossy().into_owned(),
            content: Some("backup test\n".to_string()),
            stdin: false,
            force: false,
            write: Default::default(),
        };
        let mut global = GlobalFlags {
            cwd: Some(dir.path().to_string_lossy().into_owned()),
            apply: true,
            ..GlobalFlags::default()
        };
        global.apply = true;

        let code = run(args, &global).unwrap();
        assert_eq!(code, exit::SUCCESS);

        // A backup session should exist.
        let backup_dir = dir.path().join(".patchloom/backups");
        assert!(backup_dir.exists(), "backup directory should be created");

        let sessions: Vec<_> = fs::read_dir(&backup_dir)
            .unwrap()
            .filter_map(|e| e.ok())
            .filter(|e| e.path().is_dir())
            .collect();
        assert_eq!(sessions.len(), 1, "exactly one backup session expected");
    }

    #[test]
    fn create_force_apply_creates_backup_session() {
        let dir = TempDir::new().unwrap();
        let file = dir.path().join("existing.txt");
        fs::write(&file, "original\n").unwrap();

        let args = CreateArgs {
            file: file.to_string_lossy().into_owned(),
            content: Some("overwritten\n".to_string()),
            stdin: false,
            force: true,
            write: Default::default(),
        };
        let global = GlobalFlags {
            cwd: Some(dir.path().to_string_lossy().into_owned()),
            apply: true,
            ..GlobalFlags::default()
        };

        let code = run(args, &global).unwrap();
        assert_eq!(code, exit::SUCCESS);

        // Backup session should exist with the original content.
        let backup_dir = dir.path().join(".patchloom/backups");
        assert!(backup_dir.exists(), "backup directory should be created");

        let sessions: Vec<_> = fs::read_dir(&backup_dir)
            .unwrap()
            .filter_map(|e| e.ok())
            .filter(|e| e.path().is_dir())
            .collect();
        assert_eq!(sessions.len(), 1, "exactly one backup session expected");
    }

    #[test]
    fn create_rejects_content_and_stdin_together() {
        let dir = TempDir::new().unwrap();
        let file = dir.path().join("dual_source.txt");

        let args = CreateArgs {
            file: file.to_string_lossy().into_owned(),
            content: Some("inline\n".to_string()),
            stdin: true,
            force: false,
            write: Default::default(),
        };
        let global = default_global();

        let err = run(args, &global).unwrap_err();
        assert!(
            err.to_string()
                .contains("--content and --stdin cannot be combined")
        );
    }
}