use router::xrpc::{ProcedureInput, Response, error};
use serde::{Deserialize, Serialize};
use http::status::StatusCode;
use tracing::{event, instrument, Level};
use atproto::types::Handle;
use std::str::FromStr;

#[derive(Deserialize, Debug)]
pub struct CreateAccountInput {
    pub email: Option<String>,
    pub handle: String,
    pub did: Option<String>,
    pub invite_code: Option<String>,
    pub verification_code: Option<String>,
    pub verification_phone: Option<String>,
    pub password: Option<String>,
    pub recovery_key: Option<String>,
    pub plc_op: Option<String>,
}

#[derive(Serialize, Debug)]
pub struct CreateAccountResponse {
    pub handle: String,
    pub did: String,
    // pub did_doc: Option<DidDocument>, // TODO: Define DidDocument type
    pub access_jwt: String,
    pub refresh_jwt: String,
}

#[instrument]
pub async fn create_account(data: ProcedureInput<CreateAccountInput>) -> Response {
    event!(Level::INFO, "Creating account for handle: {}", data.input.handle);
    
    // TODO: Implement the following steps based on the TypeScript reference:
    
    // 1. Input validation
    let validated_input = match validate_inputs(&data.input).await {
        Ok(input) => input,
        Err(err) => return err,
    };
    
    // 2. Check handle and email availability
    if let Err(err) = check_availability(&validated_input).await {
        return err;
    }
    
    // 3. Generate DID and signing key
    let (did, signing_key, plc_op) = match generate_identity(&validated_input).await {
        Ok(identity) => identity,
        Err(err) => return err,
    };
    
    // 4. Create actor store entry
    if let Err(err) = create_actor_store(&did, &signing_key).await {
        return err;
    }
    
    // 5. Create repository
    let repo_commit = match create_repository(&did).await {
        Ok(commit) => commit,
        Err(err) => return err,
    };
    
    // 6. Submit PLC operation (if needed)
    if let Some(op) = plc_op {
        if let Err(err) = submit_plc_operation(&did, &op).await {
            return err;
        }
    }
    
    // 7. Create account and session
    let credentials = match create_account_and_session(&validated_input, &did, &repo_commit).await {
        Ok(creds) => creds,
        Err(err) => return err,
    };
    
    // 8. Sequence events (identity, account, commit, sync)
    if let Err(err) = sequence_events(&did, &validated_input.handle, &repo_commit).await {
        return err;
    }
    
    // 9. Update repo root
    if let Err(err) = update_repo_root(&did, &repo_commit).await {
        return err;
    }
    
    // Return success response
    let response = CreateAccountResponse {
        handle: validated_input.handle,
        did: did.clone(),
        access_jwt: credentials.access_jwt,
        refresh_jwt: credentials.refresh_jwt,
    };
    
    event!(Level::INFO, "Account created successfully for DID: {}", did);
    
    // TODO: Replace with proper JSON response encoding
    error(StatusCode::OK, "success", "Account created successfully")
}

// Maximum password length (matches atproto TypeScript implementation)
const NEW_PASSWORD_MAX_LENGTH: usize = 256;

// TODO: Implement these helper functions

async fn validate_inputs(input: &CreateAccountInput) -> Result<ValidatedInput, Response> {
    // Based on validateInputsForLocalPds in the TypeScript version
    
    // Validate email is provided and has basic format
    let email = match &input.email {
        Some(e) if !e.is_empty() => e.clone(),
        _ => {
            return Err(error(
                StatusCode::BAD_REQUEST,
                "InvalidRequest",
                "Email is required"
            ));
        }
    };
    
    // Validate email format (basic validation for now)
    // TODO: Improve email validation - add proper RFC validation and disposable email checking
    // TypeScript version uses @hapi/address for validation and disposable-email-domains-js for disposable check
    if !is_valid_email(&email) {
        return Err(error(
            StatusCode::BAD_REQUEST,
            "InvalidRequest", 
            "This email address is not supported, please use a different email."
        ));
    }
    
    // Validate password length if provided
    if let Some(password) = &input.password {
        if password.len() > NEW_PASSWORD_MAX_LENGTH {
            return Err(error(
                StatusCode::BAD_REQUEST,
                "InvalidRequest",
                &format!("Password too long. Maximum length is {} characters.", NEW_PASSWORD_MAX_LENGTH)
            ));
        }
    }
    
    // Validate and normalize handle using atproto types
    let handle = Handle::from_str(&input.handle).map_err(|_| {
        error(
            StatusCode::BAD_REQUEST,
            "InvalidRequest",
            "Invalid handle format"
        )
    })?;
    
    // TODO: Invite codes - not supported for now but leave placeholder
    if input.invite_code.is_some() {
        event!(Level::INFO, "Invite codes not yet supported, ignoring");
    }
    
    Ok(ValidatedInput {
        handle: handle.to_string(),
        email: email.to_lowercase(), // Normalize email to lowercase
        password: input.password.clone(),
        invite_code: input.invite_code.clone(),
    })
}

// Basic email validation - checks for @ and . in reasonable positions
// TODO: Replace with proper email validation library like email-address crate
fn is_valid_email(email: &str) -> bool {
    // Very basic email validation
    let at_pos = email.find('@');
    let last_dot_pos = email.rfind('.');
    
    match (at_pos, last_dot_pos) {
        (Some(at), Some(dot)) => {
            // @ must come before the last dot
            // Must have content before @, between @ and dot, and after dot
            at > 0 && dot > at + 1 && dot < email.len() - 1
        }
        _ => false,
    }
}

async fn check_availability(input: &ValidatedInput) -> Result<(), Response> {
    // Check that handle and email are not already taken
    todo!("Implement availability checking")
}

async fn generate_identity(input: &ValidatedInput) -> Result<(String, SigningKey, Option<PlcOp>), Response> {
    // Generate signing key
    // Create DID and PLC operation if not provided
    todo!("Implement identity generation")
}

async fn create_actor_store(did: &str, signing_key: &SigningKey) -> Result<(), Response> {
    // Create actor store entry for the new account
    todo!("Implement actor store creation")
}

async fn create_repository(did: &str) -> Result<RepoCommit, Response> {
    // Create empty repository for the account
    todo!("Implement repository creation")
}

async fn submit_plc_operation(did: &str, plc_op: &PlcOp) -> Result<(), Response> {
    // Submit PLC operation to register/update DID
    todo!("Implement PLC operation submission")
}

async fn create_account_and_session(
    input: &ValidatedInput,
    did: &str,
    repo_commit: &RepoCommit,
) -> Result<Credentials, Response> {
    // Create account record and initial session
    // Generate JWT tokens
    todo!("Implement account and session creation")
}

async fn sequence_events(did: &str, handle: &str, repo_commit: &RepoCommit) -> Result<(), Response> {
    // Sequence identity, account, commit, and sync events
    todo!("Implement event sequencing")
}

async fn update_repo_root(did: &str, repo_commit: &RepoCommit) -> Result<(), Response> {
    // Update repository root reference
    todo!("Implement repo root update")
}

// TODO: Define these types based on our implementation needs

#[derive(Debug)]
struct ValidatedInput {
    handle: String,
    email: String,
    password: Option<String>,
    invite_code: Option<String>,
}

#[derive(Debug)]
struct SigningKey {
    // TODO: Define signing key structure
}

#[derive(Debug)]
struct PlcOp {
    // TODO: Define PLC operation structure
}

#[derive(Debug)]
struct RepoCommit {
    cid: String,
    rev: String,
}

#[derive(Debug)]
struct Credentials {
    access_jwt: String,
    refresh_jwt: String,
}