use anyhow::Result;
use serde_json::{Map, Value};
use sqlx::PgPool;
use std::collections::{BTreeSet, HashSet};
use std::fs;
use uuid::Uuid;

use crate::crypto;
use crate::db;
use crate::error::{AppError, DbErrorContext};
use crate::models::EntryRow;
use crate::taxonomy;

// ── Key/value parsing helpers ─────────────────────────────────────────────────

pub fn parse_kv(entry: &str) -> Result<(Vec<String>, Value)> {
    if let Some((key, json_str)) = entry.split_once(":=") {
        let val: Value = serde_json::from_str(json_str).map_err(|e| {
            anyhow::anyhow!(
                "Invalid JSON value for key '{}': {} (use key=value for plain strings)",
                key,
                e
            )
        })?;
        return Ok((parse_key_path(key)?, val));
    }

    if let Some((key, raw_val)) = entry.split_once('=') {
        let value = if let Some(path) = raw_val.strip_prefix('@') {
            fs::read_to_string(path)
                .map_err(|e| anyhow::anyhow!("Failed to read file '{}': {}", path, e))?
        } else {
            raw_val.to_string()
        };
        return Ok((parse_key_path(key)?, Value::String(value)));
    }

    if let Some((key, path)) = entry.split_once('@') {
        let value = fs::read_to_string(path)
            .map_err(|e| anyhow::anyhow!("Failed to read file '{}': {}", path, e))?;
        return Ok((parse_key_path(key)?, Value::String(value)));
    }

    anyhow::bail!(
        "Invalid format '{}'. Expected: key=value, key=@file, nested:key@file, or key:=<json>",
        entry
    )
}

pub fn build_json(entries: &[String]) -> Result<Value> {
    let mut map = Map::new();
    for entry in entries {
        let (path, value) = parse_kv(entry)?;
        insert_path(&mut map, &path, value)?;
    }
    Ok(Value::Object(map))
}

pub fn key_path_to_string(path: &[String]) -> String {
    path.join(":")
}

pub fn collect_key_paths(entries: &[String]) -> Result<Vec<String>> {
    entries
        .iter()
        .map(|entry| parse_kv(entry).map(|(path, _)| key_path_to_string(&path)))
        .collect()
}

pub fn collect_field_paths(entries: &[String]) -> Result<Vec<String>> {
    entries
        .iter()
        .map(|entry| parse_key_path(entry).map(|path| key_path_to_string(&path)))
        .collect()
}

pub fn parse_key_path(key: &str) -> Result<Vec<String>> {
    let path: Vec<String> = key
        .split(':')
        .map(str::trim)
        .map(ToOwned::to_owned)
        .collect();

    if path.is_empty() || path.iter().any(|part| part.is_empty()) {
        anyhow::bail!(
            "Invalid key path '{}'. Use non-empty segments like 'credentials:content'.",
            key
        );
    }
    Ok(path)
}

pub fn insert_path(map: &mut Map<String, Value>, path: &[String], value: Value) -> Result<()> {
    if path.is_empty() {
        anyhow::bail!("Key path cannot be empty");
    }
    if path.len() == 1 {
        map.insert(path[0].clone(), value);
        return Ok(());
    }
    let head = path[0].clone();
    let tail = &path[1..];
    match map.entry(head.clone()) {
        serde_json::map::Entry::Vacant(entry) => {
            let mut child = Map::new();
            insert_path(&mut child, tail, value)?;
            entry.insert(Value::Object(child));
        }
        serde_json::map::Entry::Occupied(mut entry) => match entry.get_mut() {
            Value::Object(child) => insert_path(child, tail, value)?,
            _ => {
                anyhow::bail!(
                    "Cannot set nested key '{}' because '{}' is already a non-object value",
                    key_path_to_string(path),
                    head
                );
            }
        },
    }
    Ok(())
}

pub fn remove_path(map: &mut Map<String, Value>, path: &[String]) -> Result<bool> {
    if path.is_empty() {
        anyhow::bail!("Key path cannot be empty");
    }
    if path.len() == 1 {
        return Ok(map.remove(&path[0]).is_some());
    }
    let Some(value) = map.get_mut(&path[0]) else {
        return Ok(false);
    };
    let Value::Object(child) = value else {
        return Ok(false);
    };
    let removed = remove_path(child, &path[1..])?;
    if child.is_empty() {
        map.remove(&path[0]);
    }
    Ok(removed)
}

pub fn flatten_json_fields(prefix: &str, value: &Value) -> Vec<(String, Value)> {
    match value {
        Value::Object(map) => {
            let mut out = Vec::new();
            for (k, v) in map {
                let full_key = if prefix.is_empty() {
                    k.clone()
                } else {
                    format!("{}.{}", prefix, k)
                };
                out.extend(flatten_json_fields(&full_key, v));
            }
            out
        }
        other => vec![(prefix.to_string(), other.clone())],
    }
}

// ── AddResult ─────────────────────────────────────────────────────────────────

#[derive(Debug, serde::Serialize)]
pub struct AddResult {
    pub name: String,
    pub folder: String,
    #[serde(rename = "type")]
    pub entry_type: String,
    pub tags: Vec<String>,
    pub meta_keys: Vec<String>,
    pub secret_keys: Vec<String>,
}

pub struct AddParams<'a> {
    pub name: &'a str,
    pub folder: &'a str,
    pub entry_type: &'a str,
    pub notes: &'a str,
    pub tags: &'a [String],
    pub meta_entries: &'a [String],
    pub secret_entries: &'a [String],
    pub secret_types: &'a std::collections::HashMap<String, String>,
    pub link_secret_names: &'a [String],
    /// Optional user_id for multi-user isolation (None = single-user CLI mode)
    pub user_id: Option<Uuid>,
}

pub async fn run(pool: &PgPool, params: AddParams<'_>, master_key: &[u8; 32]) -> Result<AddResult> {
    let Value::Object(mut metadata_map) = build_json(params.meta_entries)? else {
        unreachable!("build_json always returns a JSON object");
    };
    let normalized_entry_type =
        taxonomy::normalize_entry_type_and_metadata(params.entry_type, &mut metadata_map);
    let metadata = Value::Object(metadata_map);
    let secret_json = build_json(params.secret_entries)?;
    let meta_keys = collect_key_paths(params.meta_entries)?;
    let secret_keys = collect_key_paths(params.secret_entries)?;
    let flat_fields = flatten_json_fields("", &secret_json);
    let new_secret_names: BTreeSet<String> =
        flat_fields.iter().map(|(name, _)| name.clone()).collect();
    let link_secret_names =
        validate_link_secret_names(params.link_secret_names, &new_secret_names)?;

    let mut tx = pool.begin().await?;

    // Fetch existing entry by (user_id, folder, name) — the natural unique key
    let existing: Option<EntryRow> = if let Some(uid) = params.user_id {
        sqlx::query_as(
            "SELECT id, version, folder, type, tags, metadata, notes FROM entries \
             WHERE user_id = $1 AND folder = $2 AND name = $3",
        )
        .bind(uid)
        .bind(params.folder)
        .bind(params.name)
        .fetch_optional(&mut *tx)
        .await?
    } else {
        sqlx::query_as(
            "SELECT id, version, folder, type, tags, metadata, notes FROM entries \
             WHERE user_id IS NULL AND folder = $1 AND name = $2",
        )
        .bind(params.folder)
        .bind(params.name)
        .fetch_optional(&mut *tx)
        .await?
    };

    if let Some(ref ex) = existing
        && let Err(e) = db::snapshot_entry_history(
            &mut tx,
            db::EntrySnapshotParams {
                entry_id: ex.id,
                user_id: params.user_id,
                folder: params.folder,
                entry_type: &normalized_entry_type,
                name: params.name,
                version: ex.version,
                action: "add",
                tags: &ex.tags,
                metadata: &ex.metadata,
            },
        )
        .await
    {
        tracing::warn!(error = %e, "failed to snapshot entry history before upsert");
    }

    let entry_id: Uuid = if let Some(uid) = params.user_id {
        sqlx::query_scalar(
            r#"INSERT INTO entries (user_id, folder, type, name, notes, tags, metadata, version, updated_at)
               VALUES ($1, $2, $3, $4, $5, $6, $7, 1, NOW())
               ON CONFLICT (user_id, folder, name) WHERE user_id IS NOT NULL
               DO UPDATE SET
                   folder     = EXCLUDED.folder,
                   type       = EXCLUDED.type,
                   notes      = EXCLUDED.notes,
                   tags       = EXCLUDED.tags,
                   metadata   = EXCLUDED.metadata,
                   version    = entries.version + 1,
                   updated_at = NOW()
               RETURNING id"#,
        )
        .bind(uid)
        .bind(params.folder)
        .bind(&normalized_entry_type)
        .bind(params.name)
        .bind(params.notes)
        .bind(params.tags)
        .bind(&metadata)
        .fetch_one(&mut *tx)
        .await?
    } else {
        sqlx::query_scalar(
            r#"INSERT INTO entries (folder, type, name, notes, tags, metadata, version, updated_at)
               VALUES ($1, $2, $3, $4, $5, $6, 1, NOW())
               ON CONFLICT (folder, name) WHERE user_id IS NULL
               DO UPDATE SET
                   folder     = EXCLUDED.folder,
                   type       = EXCLUDED.type,
                   notes      = EXCLUDED.notes,
                   tags       = EXCLUDED.tags,
                   metadata   = EXCLUDED.metadata,
                   version    = entries.version + 1,
                   updated_at = NOW()
               RETURNING id"#,
        )
        .bind(params.folder)
        .bind(&normalized_entry_type)
        .bind(params.name)
        .bind(params.notes)
        .bind(params.tags)
        .bind(&metadata)
        .fetch_one(&mut *tx)
        .await?
    };

    let current_entry_version: i64 =
        sqlx::query_scalar("SELECT version FROM entries WHERE id = $1")
            .bind(entry_id)
            .fetch_one(&mut *tx)
            .await?;

    if existing.is_none()
        && let Err(e) = db::snapshot_entry_history(
            &mut tx,
            db::EntrySnapshotParams {
                entry_id,
                user_id: params.user_id,
                folder: params.folder,
                entry_type: &normalized_entry_type,
                name: params.name,
                version: current_entry_version,
                action: "create",
                tags: params.tags,
                metadata: &metadata,
            },
        )
        .await
    {
        tracing::warn!(error = %e, "failed to snapshot entry history on create");
    }

    if existing.is_some() {
        #[derive(sqlx::FromRow)]
        struct ExistingField {
            id: Uuid,
            name: String,
            encrypted: Vec<u8>,
        }
        let existing_fields: Vec<ExistingField> = sqlx::query_as(
            "SELECT s.id, s.name, s.encrypted \
             FROM entry_secrets es \
             JOIN secrets s ON s.id = es.secret_id \
             WHERE es.entry_id = $1",
        )
        .bind(entry_id)
        .fetch_all(&mut *tx)
        .await?;

        for f in &existing_fields {
            if let Err(e) = db::snapshot_secret_history(
                &mut tx,
                db::SecretSnapshotParams {
                    secret_id: f.id,
                    name: &f.name,
                    encrypted: &f.encrypted,
                    action: "add",
                },
            )
            .await
            {
                tracing::warn!(error = %e, "failed to snapshot secret field history");
            }
        }

        let orphan_candidates: Vec<Uuid> = existing_fields.iter().map(|f| f.id).collect();

        sqlx::query("DELETE FROM entry_secrets WHERE entry_id = $1")
            .bind(entry_id)
            .execute(&mut *tx)
            .await?;

        if !orphan_candidates.is_empty() {
            sqlx::query(
                "DELETE FROM secrets s \
                 WHERE s.id = ANY($1) \
                   AND NOT EXISTS (SELECT 1 FROM entry_secrets es WHERE es.secret_id = s.id)",
            )
            .bind(&orphan_candidates)
            .execute(&mut *tx)
            .await?;
        }
    }

    for (field_name, field_value) in &flat_fields {
        let encrypted = crypto::encrypt_json(master_key, field_value)?;
        let secret_type = params
            .secret_types
            .get(field_name)
            .map(|s| s.as_str())
            .unwrap_or("text");
        let secret_id: Uuid = sqlx::query_scalar(
            "INSERT INTO secrets (user_id, name, type, encrypted) VALUES ($1, $2, $3, $4) RETURNING id",
        )
            .bind(params.user_id)
            .bind(field_name)
            .bind(secret_type)
            .bind(&encrypted)
            .fetch_one(&mut *tx)
            .await
            .map_err(|e| AppError::from_db_error(e, DbErrorContext::secret_name(field_name)))?;
        sqlx::query("INSERT INTO entry_secrets (entry_id, secret_id) VALUES ($1, $2)")
            .bind(entry_id)
            .bind(secret_id)
            .execute(&mut *tx)
            .await?;
    }

    for link_name in &link_secret_names {
        let secret_ids: Vec<Uuid> = if let Some(uid) = params.user_id {
            sqlx::query_scalar("SELECT id FROM secrets WHERE user_id = $1 AND name = $2")
                .bind(uid)
                .bind(link_name)
                .fetch_all(&mut *tx)
                .await?
        } else {
            sqlx::query_scalar("SELECT id FROM secrets WHERE user_id IS NULL AND name = $1")
                .bind(link_name)
                .fetch_all(&mut *tx)
                .await?
        };

        match secret_ids.len() {
            0 => anyhow::bail!("Not found: secret named '{}'", link_name),
            1 => {
                sqlx::query(
                    "INSERT INTO entry_secrets (entry_id, secret_id) VALUES ($1, $2) ON CONFLICT DO NOTHING",
                )
                .bind(entry_id)
                .bind(secret_ids[0])
                .execute(&mut *tx)
                .await?;
            }
            n => anyhow::bail!(
                "Ambiguous: {} secrets named '{}' found. Please deduplicate names first.",
                n,
                link_name
            ),
        }
    }

    crate::audit::log_tx(
        &mut tx,
        params.user_id,
        "add",
        params.folder,
        &normalized_entry_type,
        params.name,
        serde_json::json!({
            "tags": params.tags,
            "meta_keys": meta_keys,
            "secret_keys": secret_keys,
        }),
    )
    .await;

    tx.commit().await?;

    Ok(AddResult {
        name: params.name.to_string(),
        folder: params.folder.to_string(),
        entry_type: normalized_entry_type,
        tags: params.tags.to_vec(),
        meta_keys,
        secret_keys,
    })
}

fn validate_link_secret_names(
    link_secret_names: &[String],
    new_secret_names: &BTreeSet<String>,
) -> Result<Vec<String>> {
    let mut deduped = Vec::new();
    let mut seen = HashSet::new();

    for raw in link_secret_names {
        let trimmed = raw.trim();
        if trimmed.is_empty() {
            anyhow::bail!("link_secret_names contains an empty name");
        }
        if new_secret_names.contains(trimmed) {
            anyhow::bail!(
                "Conflict: secret '{}' is provided both in secrets/secrets_obj and link_secret_names",
                trimmed
            );
        }
        if seen.insert(trimmed.to_string()) {
            deduped.push(trimmed.to_string());
        }
    }

    Ok(deduped)
}

#[cfg(test)]
mod tests {
    use super::*;
    use sqlx::PgPool;
    use std::collections::BTreeSet;

    #[test]
    fn parse_nested_file_shorthand() {
        use std::io::Write;
        let mut f = tempfile::NamedTempFile::new().unwrap();
        writeln!(f, "line1\nline2").unwrap();
        let path = f.path().to_str().unwrap().to_string();
        let entry = format!("credentials:content@{}", path);
        let (path_parts, value) = parse_kv(&entry).unwrap();
        assert_eq!(key_path_to_string(&path_parts), "credentials:content");
        assert!(matches!(value, Value::String(_)));
    }

    #[test]
    fn flatten_json_fields_nested() {
        let v = serde_json::json!({
            "username": "root",
            "credentials": {
                "type": "ssh",
                "content": "pem"
            }
        });
        let mut fields = flatten_json_fields("", &v);
        fields.sort_by(|a, b| a.0.cmp(&b.0));
        assert_eq!(fields[0].0, "credentials.content");
        assert_eq!(fields[1].0, "credentials.type");
        assert_eq!(fields[2].0, "username");
    }

    #[test]
    fn validate_link_secret_names_conflict_with_new_secret() {
        let mut new_names = BTreeSet::new();
        new_names.insert("password".to_string());
        let err = validate_link_secret_names(&[String::from("password")], &new_names)
            .expect_err("must fail on overlap");
        assert!(
            err.to_string()
                .contains("provided both in secrets/secrets_obj and link_secret_names")
        );
    }

    #[test]
    fn validate_link_secret_names_dedup_and_trim() {
        let names = vec![
            " shared_key ".to_string(),
            "shared_key".to_string(),
            "runner_token".to_string(),
        ];
        let deduped = validate_link_secret_names(&names, &BTreeSet::new()).unwrap();
        assert_eq!(deduped, vec!["shared_key", "runner_token"]);
    }

    async fn maybe_test_pool() -> Option<PgPool> {
        let Ok(url) = std::env::var("SECRETS_DATABASE_URL") else {
            eprintln!("skip add linkage tests: SECRETS_DATABASE_URL is not set");
            return None;
        };
        let Ok(pool) = PgPool::connect(&url).await else {
            eprintln!("skip add linkage tests: cannot connect to database");
            return None;
        };
        if let Err(e) = crate::db::migrate(&pool).await {
            eprintln!("skip add linkage tests: migrate failed: {e}");
            return None;
        }
        Some(pool)
    }

    async fn cleanup_test_rows(pool: &PgPool, marker: &str) -> Result<()> {
        sqlx::query(
            "DELETE FROM entries WHERE user_id IS NULL AND (name LIKE $1 OR folder LIKE $1)",
        )
        .bind(format!("%{marker}%"))
        .execute(pool)
        .await?;
        sqlx::query(
            "DELETE FROM secrets WHERE user_id IS NULL AND name LIKE $1 \
             AND NOT EXISTS (SELECT 1 FROM entry_secrets es WHERE es.secret_id = secrets.id)",
        )
        .bind(format!("%{marker}%"))
        .execute(pool)
        .await?;
        Ok(())
    }

    #[tokio::test]
    async fn add_links_existing_secret_by_unique_name() -> Result<()> {
        let Some(pool) = maybe_test_pool().await else {
            return Ok(());
        };
        let suffix = Uuid::from_u128(rand::random()).to_string();
        let marker = format!("link_unique_{}", &suffix[..8]);
        let secret_name = format!("{}_secret", marker);
        let entry_name = format!("{}_entry", marker);

        cleanup_test_rows(&pool, &marker).await?;

        let secret_id: Uuid = sqlx::query_scalar(
            "INSERT INTO secrets (user_id, name, type, encrypted) VALUES (NULL, $1, 'text', $2) RETURNING id",
        )
        .bind(&secret_name)
        .bind(vec![1_u8, 2, 3])
        .fetch_one(&pool)
        .await?;

        run(
            &pool,
            AddParams {
                name: &entry_name,
                folder: &marker,
                entry_type: "service",
                notes: "",
                tags: &[],
                meta_entries: &[],
                secret_entries: &[],
                secret_types: &Default::default(),
                link_secret_names: std::slice::from_ref(&secret_name),
                user_id: None,
            },
            &[0_u8; 32],
        )
        .await?;

        let linked: bool = sqlx::query_scalar(
            "SELECT EXISTS( \
               SELECT 1 FROM entry_secrets es \
               JOIN entries e ON e.id = es.entry_id \
               WHERE e.user_id IS NULL AND e.name = $1 AND es.secret_id = $2 \
             )",
        )
        .bind(&entry_name)
        .bind(secret_id)
        .fetch_one(&pool)
        .await?;
        assert!(linked);

        cleanup_test_rows(&pool, &marker).await?;
        Ok(())
    }

    #[tokio::test]
    async fn add_link_secret_name_not_found_fails() -> Result<()> {
        let Some(pool) = maybe_test_pool().await else {
            return Ok(());
        };
        let suffix = Uuid::from_u128(rand::random()).to_string();
        let marker = format!("link_missing_{}", &suffix[..8]);
        let secret_name = format!("{}_secret", marker);
        let entry_name = format!("{}_entry", marker);

        cleanup_test_rows(&pool, &marker).await?;

        let err = run(
            &pool,
            AddParams {
                name: &entry_name,
                folder: &marker,
                entry_type: "service",
                notes: "",
                tags: &[],
                meta_entries: &[],
                secret_entries: &[],
                secret_types: &Default::default(),
                link_secret_names: std::slice::from_ref(&secret_name),
                user_id: None,
            },
            &[0_u8; 32],
        )
        .await
        .expect_err("must fail when linked secret is not found");
        assert!(err.to_string().contains("Not found: secret named"));

        cleanup_test_rows(&pool, &marker).await?;
        Ok(())
    }

    #[tokio::test]
    async fn add_link_secret_name_ambiguous_fails() -> Result<()> {
        let Some(pool) = maybe_test_pool().await else {
            return Ok(());
        };
        let suffix = Uuid::from_u128(rand::random()).to_string();
        let marker = format!("link_amb_{}", &suffix[..8]);
        let secret_name = format!("{}_dup_secret", marker);
        let entry_name = format!("{}_entry", marker);

        cleanup_test_rows(&pool, &marker).await?;

        sqlx::query(
            "INSERT INTO secrets (user_id, name, type, encrypted) VALUES (NULL, $1, 'text', $2)",
        )
        .bind(&secret_name)
        .bind(vec![1_u8])
        .execute(&pool)
        .await?;
        sqlx::query(
            "INSERT INTO secrets (user_id, name, type, encrypted) VALUES (NULL, $1, 'text', $2)",
        )
        .bind(&secret_name)
        .bind(vec![2_u8])
        .execute(&pool)
        .await?;

        let err = run(
            &pool,
            AddParams {
                name: &entry_name,
                folder: &marker,
                entry_type: "service",
                notes: "",
                tags: &[],
                meta_entries: &[],
                secret_entries: &[],
                secret_types: &Default::default(),
                link_secret_names: std::slice::from_ref(&secret_name),
                user_id: None,
            },
            &[0_u8; 32],
        )
        .await
        .expect_err("must fail on ambiguous linked secret name");
        assert!(err.to_string().contains("Ambiguous:"));

        cleanup_test_rows(&pool, &marker).await?;
        Ok(())
    }

    #[tokio::test]
    async fn add_duplicate_secret_name_returns_conflict_error() -> Result<()> {
        let Some(pool) = maybe_test_pool().await else {
            return Ok(());
        };
        let suffix = Uuid::from_u128(rand::random()).to_string();
        let marker = format!("dup_secret_{}", &suffix[..8]);
        let entry_name = format!("{}_entry", marker);
        let secret_name = "shared_token";

        cleanup_test_rows(&pool, &marker).await?;

        // First add succeeds
        run(
            &pool,
            AddParams {
                name: &entry_name,
                folder: &marker,
                entry_type: "service",
                notes: "",
                tags: &[],
                meta_entries: &[],
                secret_entries: &[format!("{}=value1", secret_name)],
                secret_types: &Default::default(),
                link_secret_names: &[],
                user_id: None,
            },
            &[0_u8; 32],
        )
        .await?;

        // Second add with same secret name under same user_id should fail with ConflictSecretName
        let entry_name2 = format!("{}_entry2", marker);
        let err = run(
            &pool,
            AddParams {
                name: &entry_name2,
                folder: &marker,
                entry_type: "service",
                notes: "",
                tags: &[],
                meta_entries: &[],
                secret_entries: &[format!("{}=value2", secret_name)],
                secret_types: &Default::default(),
                link_secret_names: &[],
                user_id: None,
            },
            &[0_u8; 32],
        )
        .await
        .expect_err("must fail on duplicate secret name");

        let app_err = err
            .downcast_ref::<crate::error::AppError>()
            .expect("error should be AppError");
        assert!(
            matches!(app_err, crate::error::AppError::ConflictSecretName { .. }),
            "expected ConflictSecretName, got: {}",
            app_err
        );

        cleanup_test_rows(&pool, &marker).await?;
        Ok(())
    }
}