clauth 0.5.3

use std::path::{Path, PathBuf};

use anyhow::{Context, Result};

use crate::lock::with_state_lock;
use crate::profile::{
    AppConfig, ClaudeCredentials, Profile, atomic_write, claude_dir, profile_dir, read_json_file,
    save_profile,
};

fn claude_credentials_path() -> Result<PathBuf> {
    Ok(claude_dir()?.join(".credentials.json"))
}

fn claude_settings_path() -> Result<PathBuf> {
    Ok(claude_dir()?.join("settings.json"))
}

/// State of `~/.claude/.credentials.json` relative to a profile's stored credentials.
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub(crate) enum LinkState {
    /// Symlink resolves to the profile's stored credentials.
    LinkedTo,
    /// Path exists but is not our symlink — CC re-logged, user edited, or stale copy.
    Diverged,
    /// Path does not exist.
    Missing,
}

pub(crate) fn classify_credentials_link(active: &str) -> Result<LinkState> {
    let link = claude_credentials_path()?;
    let expected = profile_dir(active)?.join("credentials.json");
    classify_link_at(&link, &expected)
}

/// Classify a symlink at `link` against `expected`; canonical paths when resolvable.
pub(crate) fn classify_link_at(link: &Path, expected: &Path) -> Result<LinkState> {
    let meta = match link.symlink_metadata() {
        Ok(m) => m,
        Err(e) if e.kind() == std::io::ErrorKind::NotFound => return Ok(LinkState::Missing),
        Err(e) => return Err(e).context("Failed to stat .credentials.json"),
    };
    if !meta.file_type().is_symlink() {
        return Ok(LinkState::Diverged);
    }
    let target = std::fs::read_link(link).context("Failed to read .credentials.json link")?;
    if paths_equivalent(&target, expected) {
        Ok(LinkState::LinkedTo)
    } else {
        Ok(LinkState::Diverged)
    }
}

fn paths_equivalent(a: &Path, b: &Path) -> bool {
    match (std::fs::canonicalize(a), std::fs::canonicalize(b)) {
        (Ok(a), Ok(b)) => a == b,
        _ => a == b,
    }
}

/// True when the profile has no stored credentials but the live path is a regular
/// file with a completed OAuth login — first login after blank profile creation.
/// clauth adopts this rather than treating it as divergence.
pub(crate) fn is_first_login(active: &str) -> Result<bool> {
    let link = claude_credentials_path()?;
    let expected = profile_dir(active)?.join("credentials.json");
    Ok(is_first_login_at(&link, &expected))
}

/// Path-based core of [`is_first_login`], split for testing. The OAuth check
/// rejects partial writes (e.g. `{}`) so adoption waits for a completed login.
fn is_first_login_at(link: &Path, expected: &Path) -> bool {
    if expected.exists() {
        return false;
    }
    let Ok(meta) = link.symlink_metadata() else {
        return false;
    };
    if meta.file_type().is_symlink() {
        return false;
    }
    std::fs::read(link)
        .ok()
        .and_then(|bytes| serde_json::from_slice::<ClaudeCredentials>(&bytes).ok())
        .is_some_and(|creds| creds.claude_ai_oauth.is_some())
}

pub(crate) fn read_claude_credentials() -> Result<Option<ClaudeCredentials>> {
    let path = claude_credentials_path()?;
    if !path.exists() {
        return Ok(None);
    }
    read_json_file(&path).map(Some)
}

#[cfg(unix)]
pub(crate) fn create_symlink(target: &Path, link: &Path) -> Result<()> {
    std::os::unix::fs::symlink(target, link).context("Failed to create credential symlink")
}

#[cfg(windows)]
pub(crate) fn create_symlink(target: &Path, link: &Path) -> Result<()> {
    match std::os::windows::fs::symlink_file(target, link) {
        Ok(()) => Ok(()),
        Err(_) => std::fs::copy(target, link)
            .map(|_| ())
            .context("Failed to copy credentials"),
    }
}

#[cfg(not(any(unix, windows)))]
pub(crate) fn create_symlink(target: &Path, link: &Path) -> Result<()> {
    std::fs::copy(target, link)
        .map(|_| ())
        .context("Failed to copy credentials")
}

/// Symlink `~/.claude/.credentials.json` → profile's `credentials.json` (copy on
/// Windows). Refuses to overwrite a non-matching regular file — that would silently
/// drop a CC re-login the user hasn't resolved yet.
pub(crate) fn link_profile_credentials(name: &str) -> Result<()> {
    with_state_lock(|| {
        let link = claude_credentials_path()?;
        let target = profile_dir(name)?.join("credentials.json");

        if let Ok(meta) = link.symlink_metadata() {
            if !meta.file_type().is_symlink() {
                let live_bytes = std::fs::read(&link).ok();
                let target_bytes = std::fs::read(&target).ok();
                if live_bytes != target_bytes {
                    anyhow::bail!(
                        "refusing to replace .credentials.json — live file differs from profile '{name}'; resolve divergence first"
                    );
                }
            }
            std::fs::remove_file(&link).context("Failed to remove old .credentials.json")?;
        }

        if target.exists() {
            if let Some(parent) = link.parent() {
                std::fs::create_dir_all(parent)?;
            }
            create_symlink(&target, &link)?;
        }

        Ok(())
    })
}

pub(crate) fn clear_claude_credentials() -> Result<()> {
    with_state_lock(|| {
        let link = claude_credentials_path()?;
        if link.symlink_metadata().is_ok() {
            std::fs::remove_file(&link).context("Failed to remove .credentials.json")?;
        }
        Ok(())
    })
}

pub(crate) struct ClaudeEndpoint {
    pub(crate) base_url: Option<String>,
    pub(crate) api_key: Option<String>,
}

pub(crate) fn read_claude_endpoint_config() -> Result<ClaudeEndpoint> {
    let path = claude_settings_path()?;
    if !path.exists() {
        return Ok(ClaudeEndpoint {
            base_url: None,
            api_key: None,
        });
    }
    let settings: serde_json::Value = read_json_file(&path)?;
    Ok(ClaudeEndpoint {
        base_url: settings["env"]["ANTHROPIC_BASE_URL"]
            .as_str()
            .map(str::to_owned),
        api_key: settings["env"]["ANTHROPIC_AUTH_TOKEN"]
            .as_str()
            .map(str::to_owned),
    })
}

/// Patch `settings.json` `env` with profile's endpoint keys and env map;
/// strip `prev_env_keys` the new profile doesn't carry to clear stale entries.
pub(crate) fn apply_profile_to_claude_settings(
    profile: &Profile,
    prev_env_keys: &[String],
) -> Result<()> {
    with_state_lock(|| apply_profile_to_claude_settings_inner(profile, prev_env_keys))
}

fn apply_profile_to_claude_settings_inner(
    profile: &Profile,
    prev_env_keys: &[String],
) -> Result<()> {
    let path = claude_settings_path()?;

    let has_anything = profile.base_url.is_some()
        || profile.api_key.is_some()
        || !profile.env.is_empty()
        || !prev_env_keys.is_empty();
    if !has_anything && !path.exists() {
        return Ok(());
    }

    let content = build_claude_settings_json(&path, profile, prev_env_keys)?;
    if let Some(parent) = path.parent() {
        std::fs::create_dir_all(parent)?;
    }
    atomic_write(&path, content).context("Failed to write settings.json")
}

/// Build the merged settings.json content. `prev_env_keys` are stripped before
/// the new profile's env is applied; pass `&[]` on start to leave existing keys.
pub(crate) fn build_claude_settings_json(
    base_path: &Path,
    profile: &Profile,
    prev_env_keys: &[String],
) -> Result<String> {
    let mut settings: serde_json::Value = if base_path.exists() {
        read_json_file(base_path)?
    } else {
        serde_json::json!({})
    };

    if settings.get("env").is_none() {
        settings["env"] = serde_json::json!({});
    }

    let env = settings["env"]
        .as_object_mut()
        .context("settings.json `env` is not an object")?;

    for key in prev_env_keys {
        if !profile.env.contains_key(key) {
            env.remove(key);
        }
    }

    match profile.base_url.as_deref() {
        Some(url) => {
            env.insert("ANTHROPIC_BASE_URL".into(), url.into());
        }
        None => {
            env.remove("ANTHROPIC_BASE_URL");
        }
    }
    match profile.api_key.as_deref() {
        Some(key) => {
            env.insert("ANTHROPIC_AUTH_TOKEN".into(), key.into());
        }
        None => {
            env.remove("ANTHROPIC_AUTH_TOKEN");
        }
    }

    // Profile env last: explicit ANTHROPIC_* entries win over base_url/api_key.
    for (k, v) in &profile.env {
        env.insert(k.clone(), v.clone().into());
    }

    serde_json::to_string_pretty(&settings).context("Failed to serialize settings.json")
}

/// Save live `.credentials.json` into the active profile. No-op on divergence
/// (would silently overwrite stored identity); divergence is resolved via
/// `force_snapshot_active_credentials` after user confirmation. First-login
/// on a credential-less profile is adopted instead.
pub(crate) fn snapshot_active_credentials(config: &mut AppConfig) -> Result<()> {
    with_state_lock(|| {
        let Some(active) = config.state.active_profile.clone() else {
            return Ok(());
        };
        if matches!(classify_credentials_link(&active)?, LinkState::Diverged) {
            if is_first_login(&active)? {
                adopt_first_login(config, &active)?;
            }
            return Ok(());
        }
        snapshot_active_credentials_unchecked(config, &active)
    })
}

/// Store the live `.credentials.json` into the profile then replace it with a
/// symlink. Must only be called after `is_first_login` returns true.
pub(crate) fn adopt_first_login(config: &mut AppConfig, active: &str) -> Result<()> {
    with_state_lock(|| {
        snapshot_active_credentials_unchecked(config, active)?;
        force_link_profile_credentials(active)
    })
}

fn snapshot_active_credentials_unchecked(config: &mut AppConfig, active: &str) -> Result<()> {
    let credentials = read_claude_credentials()?;
    if let Some(profile) = config.find_mut(active) {
        profile.credentials = credentials;
        save_profile(profile)?;
    }
    Ok(())
}

/// Snapshot the live `.credentials.json` into the active profile unconditionally.
pub(crate) fn force_snapshot_active_credentials(config: &mut AppConfig) -> Result<()> {
    with_state_lock(|| {
        let Some(active) = config.state.active_profile.clone() else {
            return Ok(());
        };
        snapshot_active_credentials_unchecked(config, &active)
    })
}

/// Re-link `.credentials.json` to `name`'s stored credentials, overwriting the live path.
pub(crate) fn force_link_profile_credentials(name: &str) -> Result<()> {
    with_state_lock(|| {
        let link = claude_credentials_path()?;
        if link.symlink_metadata().is_ok() {
            std::fs::remove_file(&link).context("Failed to remove .credentials.json")?;
        }
        let target = profile_dir(name)?.join("credentials.json");
        if target.exists() {
            if let Some(parent) = link.parent() {
                std::fs::create_dir_all(parent)?;
            }
            create_symlink(&target, &link)?;
        }
        Ok(())
    })
}

/// True when both sides have an OAuth block and access or refresh token differs.
/// Missing data on either side returns false (snapshot/skip is safer than guessing).
pub(crate) fn credentials_diverged(
    stored: Option<&ClaudeCredentials>,
    live: Option<&ClaudeCredentials>,
) -> bool {
    let Some(stored) = stored.and_then(|c| c.claude_ai_oauth.as_ref()) else {
        return false;
    };
    let Some(live) = live.and_then(|c| c.claude_ai_oauth.as_ref()) else {
        return false;
    };
    stored.access_token != live.access_token || stored.refresh_token != live.refresh_token
}

/// Replace the symlink at `.credentials.json` with a regular file (same bytes).
/// No-op if already a regular file or absent. Prevents CC writes from bleeding
/// into the profile's storage after the user disowns the active profile.
pub(crate) fn detach_credentials_link() -> Result<()> {
    with_state_lock(|| {
        let path = claude_credentials_path()?;
        let Ok(meta) = path.symlink_metadata() else {
            return Ok(());
        };
        if !meta.file_type().is_symlink() {
            return Ok(());
        }
        let content =
            std::fs::read(&path).context("Failed to read .credentials.json before detach")?;
        std::fs::remove_file(&path).context("Failed to remove .credentials.json symlink")?;
        atomic_write(&path, content).context("Failed to write detached .credentials.json")?;
        Ok(())
    })
}

#[cfg(test)]
#[path = "../tests/inline/claude.rs"]
mod tests;