//! Shared utility functions used by tool implementations: JSON argument
//! extraction, command execution, path resolution, and edit-log persistence.

use crate::utils::CastOr;
use anyhow::Result;
use serde_json::Value;
use sha2::Digest;
use std::path::PathBuf;
use tracing::{debug, info, instrument, warn};

/// Extract a required string argument from a JSON args map.
pub fn arg_str(args: &Value, name: &str) -> Result<String> {
    args.get(name)
        .and_then(|v| v.as_str())
        .map(std::string::ToString::to_string)
        .ok_or_else(|| anyhow::anyhow!("missing required argument: {name}"))
}

/// Execute a `std::process::Command` and return its combined stdout/stderr.
///
/// Flow: spawn \u{2192} collect stdout + stderr \u{2192} check exit code \u{2192} return
/// combined output or bail with the error message.
#[instrument(skip(cmd))]
pub fn execute_cmd(cmd: &mut std::process::Command) -> Result<String> {
    let output = cmd
        .output()
        .map_err(|e| anyhow::anyhow!("command execution failed: {e}"))?;
    let stdout = String::from_utf8_lossy(&output.stdout).trim().to_string();
    let stderr = String::from_utf8_lossy(&output.stderr).trim().to_string();
    let stdout_len = stdout.len();
    let stderr_len = stderr.len();
    let combined = if stderr.is_empty() {
        stdout
    } else {
        format!("{}\n{}", stdout, stderr)
            .trim()
            .to_string()
    };
    let code = output.status.code().unwrap_or(-1);
    if output.status.success() {
        info!(exit_code = code, stdout_len, "command succeeded");
        Ok(combined)
    } else {
        warn!(exit_code = code, stderr_len, "command failed");
        anyhow::bail!("command failed with exit code {code}:\n{combined}")
    }
}

/// Resolve a tool-supplied relative path to an absolute path within a workspace
/// root, rejecting escapes.
///
/// Flow: parse optional `[idx]` prefix \u{2192} join with workspace root \u{2192}
/// canonicalize \u{2192} verify result is inside one of the workspace roots.
#[instrument(skip(workspaces))]
pub fn resolve_path(workspaces: &[PathBuf], rel: &str) -> Result<PathBuf> {
    let (ws_idx, path) = if rel.starts_with('[') {
        let close = rel
            .find(']')
            .ok_or_else(|| anyhow::anyhow!("invalid workspace prefix"))?;
        let idx: usize = rel[1..close]
            .parse()
            .map_err(|_| anyhow::anyhow!("invalid workspace index"))?;
        (idx, &rel[close + 1..])
    } else {
        (0, rel)
    };
    let base = workspaces
        .get(ws_idx)
        .ok_or_else(|| anyhow::anyhow!("workspace index {ws_idx} out of range"))?;
    let abs = if path.is_empty() {
        base.clone()
    } else {
        base.join(path)
    };
    let canon = if let Ok(c) = abs.canonicalize() {
        c
    } else {
        let base_canon = workspaces
            .iter()
            .find_map(|w| w.canonicalize().ok())
            .unwrap_or_else(|| base.clone());
        let mut resolved = base_canon.clone();
        if let Ok(rel_components) = abs.strip_prefix(&base_canon) {
            for comp in rel_components.components() {
                match comp {
                    std::path::Component::ParentDir => {
                        resolved.pop();
                    }
                    std::path::Component::CurDir => {}
                    c => resolved.push(c),
                }
            }
        }
        resolved
    };
    debug!(resolved = %canon.display(), "path resolved within workspace");
    if workspaces.iter().any(|w| canon.starts_with(w)) {
        Ok(canon)
    } else {
        warn!(path = %canon.display(), rel = rel, "path is outside all workspace roots");
        anyhow::bail!("path '{rel}' is outside all workspace roots")
    }
}

/// After a successful write/edit tool run, compute content hash and byte
/// delta, then persist an `EditLogEntry` to the session's edit log.
///
/// Flow: extract path/content/reason from args \u{2192} compute SHA-256 of content
/// \u{2192} compute byte delta \u{2192} build `EditLogEntry` \u{2192} open repo \u{2192} append entry.
#[instrument(skip(args, session_dir))]
pub fn log_write_edit_tool(
    args: &serde_json::Value,
    tool_name: &str,
    origin_tag: &str,
    session_dir: &std::path::Path,
    session_id: &str,
) {
    let reason = args
        .get("reason")
        .and_then(|v| v.as_str())
        .unwrap_or("unnamed");
    let path = args
        .get("path")
        .and_then(|v| v.as_str())
        .unwrap_or("unknown");
    let content = args.get("content").or_else(|| args.get("new"));
    let content_str = content.and_then(|v| v.as_str()).unwrap_or("");
    let content_sha256 = hex::encode(sha2::Sha256::digest(content_str.as_bytes()));
    let bytes_delta = if tool_name == "write" {
        content_str.len().cast_or(0i64)
    } else {
        let old = args.get("old").and_then(|v| v.as_str()).unwrap_or("");
        let new = args.get("new").and_then(|v| v.as_str()).unwrap_or("");
        let new_len: i64 = new.len().cast_or(0i64);
        let old_len: i64 = old.len().cast_or(0i64);
        (new_len - old_len).abs()
    };
    let entry = zesdex_domain::cms::EditLogEntry {
        ts: chrono::Utc::now().timestamp_millis(),
        tool: tool_name.to_string(),
        path: path.to_string(),
        reason: reason.to_string(),
        content_sha256,
        bytes_delta,
        origin: origin_tag.to_string(),
        session_id: session_id.to_string(),
    };
    use zesdex_domain::cms::repository::EditLogRepository;
    let repo = crate::persistence::cms::edit_log_repo::JsonlEditLogRepository::new();
    if let Ok(mut el) = repo.open(session_dir) {
        let _ = repo.append(session_dir, &mut el, entry);
        debug!(tool = tool_name, path = path, "edit-log entry persisted");
    } else {
        warn!(tool = tool_name, path = path, "failed to open edit-log repository");
    }
}