#![allow(dead_code)]

use diesel::prelude::*;
use diesel::sqlite::SqliteConnection;
use std::ops::DerefMut;
use std::sync::{Arc, Mutex};

use crate::database::models::{InsertPersona, Persona};
use crate::database::schema;
use crate::database::{DbError, DbErrorKind, connect};
use crate::otel::trace_db_call;

/// Patch shape for update_persona. None = leave field alone. Built-ins are
/// allowed to flip `include_all_memories` but should reject name/prompt
/// edits at the handler layer (built-in copy lives in the migration).
pub struct PersonaPatch {
    pub name: Option<String>,
    pub system_prompt: Option<String>,
    pub include_all_memories: Option<bool>,
}

/// One row of a bulk migration upload. Fields named to match the JSON
/// shape the mobile client uploads (`POST /personas/migrate`).
pub struct ImportPersona {
    pub persona_id: String,
    pub name: String,
    pub system_prompt: String,
    pub is_built_in: bool,
    pub created_at: i64,
}

pub trait PersonaDao: Sync + Send {
    fn list_personas(
        &mut self,
        cx: &opentelemetry::Context,
        user_id: i32,
    ) -> Result<Vec<Persona>, DbError>;

    fn get_persona(
        &mut self,
        cx: &opentelemetry::Context,
        user_id: i32,
        persona_id: &str,
    ) -> Result<Option<Persona>, DbError>;

    fn create_persona(
        &mut self,
        cx: &opentelemetry::Context,
        user_id: i32,
        persona_id: &str,
        name: &str,
        system_prompt: &str,
        is_built_in: bool,
        include_all_memories: bool,
    ) -> Result<Persona, DbError>;

    fn update_persona(
        &mut self,
        cx: &opentelemetry::Context,
        user_id: i32,
        persona_id: &str,
        patch: PersonaPatch,
    ) -> Result<Option<Persona>, DbError>;

    fn delete_persona(
        &mut self,
        cx: &opentelemetry::Context,
        user_id: i32,
        persona_id: &str,
    ) -> Result<bool, DbError>;

    /// Idempotent bulk import. INSERT OR IGNORE on (user_id, persona_id)
    /// — re-uploading the same set is a no-op. Returns the number of rows
    /// actually inserted (skipped duplicates don't count).
    fn bulk_import(
        &mut self,
        cx: &opentelemetry::Context,
        user_id: i32,
        personas: &[ImportPersona],
    ) -> Result<usize, DbError>;
}

pub struct SqlitePersonaDao {
    connection: Arc<Mutex<SqliteConnection>>,
}

impl Default for SqlitePersonaDao {
    fn default() -> Self {
        Self::new()
    }
}

impl SqlitePersonaDao {
    pub fn new() -> Self {
        Self {
            connection: Arc::new(Mutex::new(connect())),
        }
    }

    pub fn from_connection(conn: Arc<Mutex<SqliteConnection>>) -> Self {
        Self { connection: conn }
    }
}

impl PersonaDao for SqlitePersonaDao {
    fn list_personas(
        &mut self,
        cx: &opentelemetry::Context,
        uid: i32,
    ) -> Result<Vec<Persona>, DbError> {
        trace_db_call(cx, "query", "list_personas", |_span| {
            use schema::personas::dsl::*;
            let mut conn = self.connection.lock().expect("PersonaDao lock");
            personas
                .filter(user_id.eq(uid))
                .order(created_at.asc())
                .load::<Persona>(conn.deref_mut())
                .map_err(|e| anyhow::anyhow!("Query error: {}", e))
        })
        .map_err(|_| DbError::new(DbErrorKind::QueryError))
    }

    fn get_persona(
        &mut self,
        cx: &opentelemetry::Context,
        uid: i32,
        pid: &str,
    ) -> Result<Option<Persona>, DbError> {
        trace_db_call(cx, "query", "get_persona", |_span| {
            use schema::personas::dsl::*;
            let mut conn = self.connection.lock().expect("PersonaDao lock");
            personas
                .filter(user_id.eq(uid))
                .filter(persona_id.eq(pid))
                .first::<Persona>(conn.deref_mut())
                .optional()
                .map_err(|e| anyhow::anyhow!("Query error: {}", e))
        })
        .map_err(|_| DbError::new(DbErrorKind::QueryError))
    }

    fn create_persona(
        &mut self,
        cx: &opentelemetry::Context,
        uid: i32,
        pid: &str,
        nm: &str,
        prompt: &str,
        builtin: bool,
        include_all: bool,
    ) -> Result<Persona, DbError> {
        trace_db_call(cx, "insert", "create_persona", |_span| {
            use schema::personas::dsl::*;
            let mut conn = self.connection.lock().expect("PersonaDao lock");
            let now = chrono::Utc::now().timestamp_millis();

            diesel::insert_into(personas)
                .values(InsertPersona {
                    user_id: uid,
                    persona_id: pid,
                    name: nm,
                    system_prompt: prompt,
                    is_built_in: builtin,
                    include_all_memories: include_all,
                    created_at: now,
                    updated_at: now,
                })
                .execute(conn.deref_mut())
                .map_err(|e| anyhow::anyhow!("Insert error: {}", e))?;

            personas
                .filter(user_id.eq(uid))
                .filter(persona_id.eq(pid))
                .first::<Persona>(conn.deref_mut())
                .map_err(|e| anyhow::anyhow!("Query error: {}", e))
        })
        .map_err(|_| DbError::new(DbErrorKind::InsertError))
    }

    fn update_persona(
        &mut self,
        cx: &opentelemetry::Context,
        uid: i32,
        pid: &str,
        patch: PersonaPatch,
    ) -> Result<Option<Persona>, DbError> {
        trace_db_call(cx, "update", "update_persona", |_span| {
            use schema::personas::dsl::*;
            let mut conn = self.connection.lock().expect("PersonaDao lock");
            let now = chrono::Utc::now().timestamp_millis();

            // Apply each field as its own UPDATE — keeps types simple
            // (Diesel's tuple updates don't compose cleanly across optional
            // columns) and matches the pattern already in use for entities
            // (knowledge_dao.rs::update_entity).
            if let Some(ref new_name) = patch.name {
                diesel::update(personas.filter(user_id.eq(uid)).filter(persona_id.eq(pid)))
                    .set((name.eq(new_name), updated_at.eq(now)))
                    .execute(conn.deref_mut())
                    .map_err(|e| anyhow::anyhow!("Update name error: {}", e))?;
            }
            if let Some(ref new_prompt) = patch.system_prompt {
                diesel::update(personas.filter(user_id.eq(uid)).filter(persona_id.eq(pid)))
                    .set((system_prompt.eq(new_prompt), updated_at.eq(now)))
                    .execute(conn.deref_mut())
                    .map_err(|e| anyhow::anyhow!("Update prompt error: {}", e))?;
            }
            if let Some(new_include_all) = patch.include_all_memories {
                diesel::update(personas.filter(user_id.eq(uid)).filter(persona_id.eq(pid)))
                    .set((include_all_memories.eq(new_include_all), updated_at.eq(now)))
                    .execute(conn.deref_mut())
                    .map_err(|e| anyhow::anyhow!("Update include_all error: {}", e))?;
            }

            personas
                .filter(user_id.eq(uid))
                .filter(persona_id.eq(pid))
                .first::<Persona>(conn.deref_mut())
                .optional()
                .map_err(|e| anyhow::anyhow!("Query error: {}", e))
        })
        .map_err(|_| DbError::new(DbErrorKind::UpdateError))
    }

    fn delete_persona(
        &mut self,
        cx: &opentelemetry::Context,
        uid: i32,
        pid: &str,
    ) -> Result<bool, DbError> {
        trace_db_call(cx, "delete", "delete_persona", |_span| {
            use schema::personas::dsl::*;
            let mut conn = self.connection.lock().expect("PersonaDao lock");
            let n = diesel::delete(personas.filter(user_id.eq(uid)).filter(persona_id.eq(pid)))
                .execute(conn.deref_mut())
                .map_err(|e| anyhow::anyhow!("Delete error: {}", e))?;
            Ok(n > 0)
        })
        .map_err(|_| DbError::new(DbErrorKind::QueryError))
    }

    fn bulk_import(
        &mut self,
        cx: &opentelemetry::Context,
        uid: i32,
        rows: &[ImportPersona],
    ) -> Result<usize, DbError> {
        trace_db_call(cx, "insert", "bulk_import_personas", |_span| {
            let mut conn = self.connection.lock().expect("PersonaDao lock");
            let now = chrono::Utc::now().timestamp_millis();
            let mut inserted = 0usize;

            // INSERT OR IGNORE on the (user_id, persona_id) UNIQUE so
            // re-running migrate is a no-op for personas already on the
            // server.
            for p in rows {
                let n = diesel::sql_query(
                    "INSERT OR IGNORE INTO personas (user_id, persona_id, name, system_prompt, \
                     is_built_in, include_all_memories, created_at, updated_at) \
                     VALUES (?, ?, ?, ?, ?, 0, ?, ?)",
                )
                .bind::<diesel::sql_types::Integer, _>(uid)
                .bind::<diesel::sql_types::Text, _>(&p.persona_id)
                .bind::<diesel::sql_types::Text, _>(&p.name)
                .bind::<diesel::sql_types::Text, _>(&p.system_prompt)
                .bind::<diesel::sql_types::Bool, _>(p.is_built_in)
                .bind::<diesel::sql_types::BigInt, _>(p.created_at)
                .bind::<diesel::sql_types::BigInt, _>(now)
                .execute(conn.deref_mut())
                .map_err(|e| anyhow::anyhow!("Insert error: {}", e))?;
                inserted += n;
            }
            Ok(inserted)
        })
        .map_err(|_| DbError::new(DbErrorKind::InsertError))
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::database::test::in_memory_db_connection;

    fn dao_with_user(username: &str) -> (SqlitePersonaDao, i32) {
        use crate::database::schema::users::dsl as u;
        let conn = Arc::new(Mutex::new(in_memory_db_connection()));
        diesel::insert_into(u::users)
            .values((u::username.eq(username), u::password.eq("x")))
            .execute(conn.lock().unwrap().deref_mut())
            .unwrap();
        let user_id: i32 = u::users
            .filter(u::username.eq(username))
            .select(u::id)
            .first(conn.lock().unwrap().deref_mut())
            .unwrap();
        (SqlitePersonaDao::from_connection(conn), user_id)
    }

    #[test]
    fn create_and_list_round_trip() {
        let cx = opentelemetry::Context::new();
        let (mut dao, uid) = dao_with_user("alice");

        // The migration seeds 3 built-ins for any existing user; alice
        // was created post-migration so she starts empty.
        let p = dao
            .create_persona(&cx, uid, "custom-1", "Custom A", "prompt A", false, false)
            .unwrap();
        assert_eq!(p.persona_id, "custom-1");
        assert_eq!(p.user_id, uid);
        assert!(!p.is_built_in);

        let list = dao.list_personas(&cx, uid).unwrap();
        assert_eq!(list.len(), 1);
        assert_eq!(list[0].persona_id, "custom-1");
    }

    #[test]
    fn unique_constraint_blocks_duplicate_persona_id() {
        let cx = opentelemetry::Context::new();
        let (mut dao, uid) = dao_with_user("bob");

        dao.create_persona(&cx, uid, "x", "X", "p", false, false)
            .unwrap();
        let err = dao.create_persona(&cx, uid, "x", "X2", "p2", false, false);
        assert!(
            err.is_err(),
            "second insert with same persona_id should fail"
        );
    }

    #[test]
    fn bulk_import_is_idempotent() {
        let cx = opentelemetry::Context::new();
        let (mut dao, uid) = dao_with_user("carol");

        let rows = vec![
            ImportPersona {
                persona_id: "custom-a".into(),
                name: "A".into(),
                system_prompt: "p1".into(),
                is_built_in: false,
                created_at: 1,
            },
            ImportPersona {
                persona_id: "custom-b".into(),
                name: "B".into(),
                system_prompt: "p2".into(),
                is_built_in: false,
                created_at: 2,
            },
        ];

        let first = dao.bulk_import(&cx, uid, &rows).unwrap();
        assert_eq!(first, 2);
        let second = dao.bulk_import(&cx, uid, &rows).unwrap();
        assert_eq!(second, 0, "re-import should insert nothing");

        assert_eq!(dao.list_personas(&cx, uid).unwrap().len(), 2);
    }

    #[test]
    fn dao_update_does_not_block_built_ins() {
        // Documenting contract: the DAO is intentionally permissive —
        // `update_persona` will apply name/system_prompt edits to ANY
        // row, including built-ins. The guard against editing built-in
        // identity (name + systemPrompt) lives in the HTTP handler
        // (src/personas.rs::update_persona). If you find yourself
        // wanting to add the guard here too, prefer that — defence in
        // depth — but keep this test passing so anyone who removes
        // the handler guard gets a failing call site, not silent data
        // corruption.
        let cx = opentelemetry::Context::new();
        let (mut dao, uid) = dao_with_user("eve");

        dao.create_persona(&cx, uid, "default", "Default", "old", true, false)
            .unwrap();
        let updated = dao
            .update_persona(
                &cx,
                uid,
                "default",
                PersonaPatch {
                    name: Some("Renamed".into()),
                    system_prompt: Some("new prompt".into()),
                    include_all_memories: None,
                },
            )
            .unwrap()
            .unwrap();
        assert_eq!(updated.name, "Renamed");
        assert_eq!(updated.system_prompt, "new prompt");
        assert!(
            updated.is_built_in,
            "is_built_in flag should be unchanged by patch"
        );
    }

    #[test]
    fn update_toggles_include_all_memories() {
        let cx = opentelemetry::Context::new();
        let (mut dao, uid) = dao_with_user("dan");

        dao.create_persona(&cx, uid, "j", "Journal", "p", true, false)
            .unwrap();
        let updated = dao
            .update_persona(
                &cx,
                uid,
                "j",
                PersonaPatch {
                    name: None,
                    system_prompt: None,
                    include_all_memories: Some(true),
                },
            )
            .unwrap()
            .unwrap();
        assert!(updated.include_all_memories);
    }
}