nxtgauge-backend-rust/apps/users/src/handlers/ai.rs

use crate::AppState;
use axum::{
    extract::State,
    http::StatusCode,
    response::IntoResponse,
    routing::{get, post},
    Json, Router,
};
use contracts::auth_middleware::AuthUser;
use serde::{Deserialize, Serialize};
use std::sync::Arc;
use uuid::Uuid;

#[derive(sqlx::FromRow)]
struct KbArticleRow {
    id: Uuid,
    title: String,
    slug: String,
    summary: Option<String>,
    category_name: String,
}

pub fn ai_router() -> Router<AppState> {
    Router::new()
        .route("/chat/message", post(ai_chat_message))
        .route("/tickets/create", post(ai_create_ticket))
        .route("/tickets/{id}", get(ai_get_ticket))
        .route("/forms/extract", post(ai_extract_form))
        .route("/generate-job-field", post(ai_generate_job_field))
        .route("/generate-cover-letter", post(ai_generate_cover_letter))
        .route("/tailor-resume", post(ai_tailor_resume))
        .route("/auto-apply", post(ai_auto_apply))
        .route("/auto-respond-to-lead", post(ai_auto_respond_to_lead))
        .route("/usage", get(ai_usage_status))
}

#[derive(Debug, Clone, Deserialize, Serialize)]
pub struct OllamaChatRequest {
    pub model: Option<String>,
    pub message: String,
    pub conversation_id: Option<String>,
    pub user_id: Option<String>,
}

#[derive(Debug, Clone, Deserialize, Serialize)]
pub struct OllamaChatResponse {
    pub message: String,
    pub conversation_id: String,
    pub intent: String,
    pub confidence: f32,
}

#[derive(Debug, Clone, Deserialize, Serialize)]
struct OllamaGenerateRequest {
    model: String,
    prompt: String,
    stream: bool,
}

#[derive(Debug, Clone, Deserialize, Serialize)]
struct OllamaGenerateResponse {
    response: String,
}

async fn call_ollama(_state: &AppState, model: &str, prompt: &str) -> Result<String, String> {
    let base_url = std::env::var("OLLAMA_BASE_URL").unwrap_or_else(|_| "http://ollama.nxtgauge-ai.svc.cluster.local:11434".to_string());
    let url = format!("{}/api/generate", base_url);

    let req = OllamaGenerateRequest {
        model: model.to_string(),
        prompt: prompt.to_string(),
        stream: false,
    };

    let client = reqwest::Client::new();
    let response = client
        .post(&url)
        .json(&req)
        .send()
        .await
        .map_err(|e| format!("ollama request failed: {}", e))?;

    if !response.status().is_success() {
        return Err(format!("ollama returned status: {}", response.status()));
    }

    let result: OllamaGenerateResponse = response
        .json()
        .await
        .map_err(|e| format!("failed to parse ollama response: {}", e))?;

    Ok(result.response)
}

async fn classify_intent(message: &str, ollama_base: &str, model: &str) -> (String, f32) {
    let prompt = format!(
        "Classify this user message into one intent category. Categories: ticket_creation, form_filling, help_search, job_description_generation, general. \
         Return ONLY the intent name, nothing else.\n\nMessage: {}",
        message
    );

    match call_ollama_inline(ollama_base, model, &prompt).await {
        Ok(response) => {
            let intent = response.trim().to_lowercase();
            let confidence = if intent.is_empty() { 0.5 } else { 0.85 };
            let intent = match intent.as_str() {
                "ticket_creation" => "ticket_creation",
                "form_filling" => "form_filling",
                "help_search" => "help_search",
                "job_description_generation" => "job_description_generation",
                _ => "general",
            };
            (intent.to_string(), confidence)
        }
        Err(_) => ("general".to_string(), 0.5),
    }
}

async fn call_ollama_inline(base_url: &str, model: &str, prompt: &str) -> Result<String, String> {
    let url = format!("{}/api/generate", base_url);
    let req = OllamaGenerateRequest {
        model: model.to_string(),
        prompt: prompt.to_string(),
        stream: false,
    };

    let client = reqwest::Client::new();
    let response = client
        .post(&url)
        .json(&req)
        .send()
        .await
        .map_err(|e| format!("ollama request failed: {}", e))?;

    if !response.status().is_success() {
        return Err(format!("ollama returned status: {}", response.status()));
    }

    let result: OllamaGenerateResponse = response
        .json()
        .await
        .map_err(|e| format!("failed to parse ollama response: {}", e))?;

    Ok(result.response)
}

async fn ai_chat_message(
    State(state): State<AppState>,
    Json(body): Json<OllamaChatRequest>,
) -> impl IntoResponse {
    let ollama_base = std::env::var("OLLAMA_BASE_URL").unwrap_or_else(|_| "http://ollama.nxtgauge-ai.svc.cluster.local:11434".to_string());
    let model = std::env::var("OLLAMA_CHAT_MODEL").unwrap_or_else(|_| "gemma3:270m".to_string());
    let default_conversation = Uuid::new_v4().to_string();

    let conversation_id = body.conversation_id.unwrap_or_else(|| default_conversation);

    let (intent, confidence) = classify_intent(&body.message, &ollama_base, &model).await;

    let response_text = match intent.as_str() {
        "help_search" => {
            let q = body.message.to_lowercase();
            let rows = sqlx::query_as::<_, KbArticleRow>(
                r#"
                SELECT a.id, a.title, a.slug, a.summary, c.name AS category_name
                FROM kb_articles a
                JOIN kb_categories c ON c.id = a.category_id
                WHERE a.status = 'PUBLISHED'
                  AND c.is_active = true
                  AND (LOWER(a.title) LIKE '%' || $1 || '%'
                       OR LOWER(COALESCE(a.summary, '')) LIKE '%' || $1 || '%')
                ORDER BY a.updated_at DESC
                LIMIT 5
                "#,
            )
            .bind(&q)
            .fetch_all(&state.pool)
            .await;

            match rows {
                Ok(articles) if !articles.is_empty() => {
                    let links: Vec<String> = articles
                        .iter()
                        .map(|a| {
                            format!(
                                "- **{}** ({})\n  {}\n  /help-center/article/{}",
                                a.title,
                                a.category_name,
                                a.summary.as_deref().unwrap_or(""),
                                a.slug
                            )
                        })
                        .collect();
                    format!(
                        "I found {} help article(s) for you:\n\n{}\n\nIs any of these what you were looking for?",
                        articles.len(),
                        links.join("\n\n")
                    )
                }
                _ => {
                    "I couldn't find any help articles matching your question. \
                     Try rephrasing or contact support if you need further assistance."
                        .to_string()
                }
            }
        }
        "job_description_generation" => {
            let jd_prompt = format!(
                "Generate a professional job description with the following sections: \
                 **Job Title**, **Summary**, **Key Responsibilities**, **Required Skills & Qualifications**, \
                 **Preferred Qualifications**, **What We Offer**. \
                 Format each section clearly with bullet points where appropriate.\n\n\
                 User's request: {}\n\n\
                 Job Description:",
                body.message
            );
            match call_ollama(&state, &model, &jd_prompt).await {
                Ok(r) => r,
                Err(e) => {
                    tracing::error!("Ollama JD generation error: {}", e);
                    "I'm having trouble generating a job description right now. Please try again.".to_string()
                }
            }
        }
        "ticket_creation" => {
            let system_prompt = "You are a support ticket assistant. Help users create clear, actionable support tickets. \
             Ask for: subject, description of issue, category, priority if not provided. \
             Summarize the ticket in a structured way.";
            let full_prompt = format!("{}\n\nUser: {}\nAssistant:", system_prompt, body.message);
            match call_ollama(&state, &model, &full_prompt).await {
                Ok(r) => r,
                Err(e) => {
                    tracing::error!("Ollama error: {}", e);
                    "I'm having trouble processing your request right now. Please try again or contact support.".to_string()
                }
            }
        }
        "form_filling" => {
            let system_prompt = "You are a form filling assistant. Help users fill out forms by extracting relevant information \
             from their message. Extract key:value pairs when possible.";
            let full_prompt = format!("{}\n\nUser: {}\nAssistant:", system_prompt, body.message);
            match call_ollama(&state, &model, &full_prompt).await {
                Ok(r) => r,
                Err(e) => {
                    tracing::error!("Ollama error: {}", e);
                    "I'm having trouble processing your request right now. Please try again or contact support.".to_string()
                }
            }
        }
        _ => {
            let system_prompt = "You are a helpful AI assistant for Nxtgauge platform. Provide clear, concise responses. \
             If the user needs support, guide them to create a ticket.";
            let full_prompt = format!("{}\n\nUser: {}\nAssistant:", system_prompt, body.message);
            match call_ollama(&state, &model, &full_prompt).await {
                Ok(r) => r,
                Err(e) => {
                    tracing::error!("Ollama error: {}", e);
                    "I'm having trouble processing your request right now. Please try again or contact support.".to_string()
                }
            }
        }
    };

    (
        StatusCode::OK,
        Json(OllamaChatResponse {
            message: response_text,
            conversation_id,
            intent,
            confidence,
        }),
    )
        .into_response()
}

async fn ai_create_ticket(
    State(state): State<AppState>,
    Json(body): Json<serde_json::Value>,
) -> impl IntoResponse {
    let subject = body.get("subject").and_then(|v| v.as_str()).unwrap_or("AI Assisted Request");
    let description = body.get("description").and_then(|v| v.as_str());
    let category = body.get("category").and_then(|v| v.as_str()).unwrap_or("ai_assisted");
    let priority = body.get("priority").and_then(|v| v.as_str()).unwrap_or("medium");
    let user_id = body.get("user_id").and_then(|v| v.as_str())
        .and_then(|s| Uuid::parse_str(s).ok())
        .unwrap_or_else(Uuid::nil);

    let result = sqlx::query_as::<_, TicketRow>(
        r#"
        INSERT INTO support_tickets (user_id, subject, description, category, priority, status)
        VALUES ($1, $2, $3, $4, $5, 'new')
        RETURNING id, subject, description, category, priority, status,
                  requester_name, requester_email, assigned_to, created_at, updated_at
        "#,
    )
    .bind(user_id)
    .bind(subject)
    .bind(description)
    .bind(category)
    .bind(priority)
    .fetch_one(&state.pool)
    .await;

    match result {
        Ok(r) => (
            StatusCode::CREATED,
            Json(serde_json::json!({
                "id": r.id,
                "subject": r.subject,
                "status": r.status,
                "ticket_id": r.id,
            })),
        )
            .into_response(),
        Err(e) => {
            tracing::error!("AI ticket creation failed: {}", e);
            (StatusCode::INTERNAL_SERVER_ERROR, Json(serde_json::json!({ "error": "Failed to create ticket" }))).into_response()
        }
    }
}

async fn ai_get_ticket(
    State(state): State<AppState>,
    axum::extract::Path(id): axum::extract::Path<Uuid>,
) -> impl IntoResponse {
    let result = sqlx::query_as::<_, TicketRow>(
        r#"
        SELECT id, subject, description, category, priority, status,
               requester_name, requester_email, assigned_to, created_at, updated_at
        FROM support_tickets WHERE id = $1
        "#,
    )
    .bind(id)
    .fetch_optional(&state.pool)
    .await;

    match result {
        Ok(Some(r)) => (
            StatusCode::OK,
            Json(serde_json::json!({
                "id": r.id,
                "subject": r.subject,
                "description": r.description,
                "category": r.category,
                "priority": r.priority,
                "status": r.status,
                "requester_name": r.requester_name,
                "requester_email": r.requester_email,
                "assigned_to": r.assigned_to,
                "created_at": r.created_at,
                "updated_at": r.updated_at,
            })),
        )
            .into_response(),
        Ok(None) => (StatusCode::NOT_FOUND, Json(serde_json::json!({ "error": "Ticket not found" }))).into_response(),
        Err(e) => {
            tracing::error!("Failed to fetch ticket {}: {}", id, e);
            (StatusCode::INTERNAL_SERVER_ERROR, Json(serde_json::json!({ "error": "Failed to fetch ticket" }))).into_response()
        }
    }
}

#[derive(Debug, Deserialize)]
struct FormExtractBody {
    message: String,
    form_type: Option<String>,
}

#[derive(Debug, Serialize)]
struct FormExtractResponse {
    fields: Vec<ExtractedField>,
    missing_fields: Vec<String>,
    confidence: f32,
}

#[derive(Debug, Serialize)]
struct ExtractedField {
    key: String,
    value: String,
    confidence: f32,
}

async fn ai_extract_form(
    State(_state): State<AppState>,
    Json(body): Json<FormExtractBody>,
) -> impl IntoResponse {
    let ollama_base = std::env::var("OLLAMA_BASE_URL").unwrap_or_else(|_| "http://ollama.nxtgauge-ai.svc.cluster.local:11434".to_string());
    let model = std::env::var("OLLAMA_CHAT_MODEL").unwrap_or_else(|_| "gemma3:270m".to_string());

    let form_type = body.form_type.unwrap_or_else(|| "generic".to_string());

    let prompt = format!(
        "Extract key:value pairs from this message for a {} form. \
         Return ONLY a JSON object with the fields you can identify. \
         Use camelCase for field names.\n\nMessage: {}",
        form_type, body.message
    );

    let response_text = match call_ollama_inline(&ollama_base, &model, &prompt).await {
        Ok(r) => r,
        Err(e) => {
            tracing::error!("Ollama form extraction error: {}", e);
            return (StatusCode::INTERNAL_SERVER_ERROR, Json(serde_json::json!({ "error": "Form extraction failed" }))).into_response();
        }
    };

    let extracted: serde_json::Value = serde_json::from_str(&response_text)
        .unwrap_or_else(|_| serde_json::json!({}));

    let mut fields = Vec::new();
    let missing_fields = Vec::new();

    if let Some(obj) = extracted.as_object() {
        for (key, value) in obj {
            fields.push(ExtractedField {
                key: key.clone(),
                value: value.to_string(),
                confidence: 0.8,
            });
        }
    }

    let confidence = if fields.is_empty() { 0.3 } else { 0.75 };

    (StatusCode::OK, Json(FormExtractResponse {
        fields,
        missing_fields,
        confidence,
    })).into_response()
}

#[derive(sqlx::FromRow)]
struct TicketRow {
    id: Uuid,
    subject: String,
    description: Option<String>,
    category: String,
    priority: String,
    status: String,
    requester_name: Option<String>,
    requester_email: Option<String>,
    assigned_to: Option<Uuid>,
    created_at: chrono::DateTime<chrono::Utc>,
    updated_at: chrono::DateTime<chrono::Utc>,
}

// ── AI Pack & Rate Limit Helpers ────────────────────────────────────────────────

const BASE_AI_LIMIT: i32 = 5;

fn get_ai_limit_for_package(features: &serde_json::Value) -> i32 {
    features
        .get("ai_generations_per_day")
        .and_then(|v| v.as_i64())
        .map(|v| v as i32)
        .unwrap_or(BASE_AI_LIMIT)
}

async fn has_active_ai_pack(
    pool: &sqlx::PgPool,
    user_role_profile_id: Uuid,
    role_key: &str,
) -> (bool, i32) {
    let now = chrono::Utc::now();
    let result = sqlx::query_as::<_, (Option<serde_json::Value>,)>(
        r#"
        SELECT pp.features
        FROM pricing_packages pp
        JOIN payments p ON p.package_id = pp.id
        WHERE pp.package_type = 'AI_PACK'
          AND pp.is_active = true
          AND p.user_role_profile_id = $1
          AND $2 = ANY(pp.applicable_roles)
          AND p.tracecoins_credited > 0
          AND (pp.valid_from IS NULL OR pp.valid_from <= $3)
          AND (pp.valid_until IS NULL OR pp.valid_until >= $3)
        ORDER BY p.created_at DESC
        LIMIT 1
        "#,
    )
    .bind(user_role_profile_id)
    .bind(role_key)
    .bind(now)
    .fetch_optional(pool)
    .await;

    match result {
        Ok(Some((Some(features),))) => {
            let limit = get_ai_limit_for_package(&features);
            (true, limit)
        }
        _ => (false, BASE_AI_LIMIT),
    }
}

async fn check_and_increment_usage(
    pool: &sqlx::PgPool,
    profile_id: Uuid,
    is_company: bool,
    daily_limit: i32,
) -> Result<(i32, i32), String> {
    let today = chrono::Utc::now().date_naive();
    let table = if is_company { "company_ai_usage" } else { "job_seeker_ai_usage" };
    let id_col = if is_company { "company_id" } else { "job_seeker_id" };

    let current: Option<i32> = sqlx::query_scalar(&format!(
        "SELECT generations_used FROM {} WHERE {} = $1 AND usage_date = $2",
        table, id_col
    ))
    .bind(profile_id)
    .bind(today)
    .fetch_optional(pool)
    .await
    .map_err(|e| e.to_string())?;

    let used = current.unwrap_or(0);
    if used >= daily_limit {
        return Err("Daily AI generation limit reached".to_string());
    }

    sqlx::query(&format!(
        r#"
        INSERT INTO {} ({} , usage_date, generations_used)
        VALUES ($1, $2, 1)
        ON CONFLICT ({}, usage_date)
        DO UPDATE SET generations_used = {}.generations_used + 1, updated_at = NOW()
        "#,
        table, id_col, id_col, table
    ))
    .bind(profile_id)
    .bind(today)
    .execute(pool)
    .await
    .map_err(|e| e.to_string())?;

    Ok((used + 1, daily_limit))
}

// ── Job Field Generation (Companies) ──────────────────────────────────────────

#[derive(Debug, Deserialize)]
struct GenerateJobFieldBody {
    field: String,
    context: String,
}

#[derive(Debug, Serialize)]
struct GenerateFieldResponse {
    generated_text: String,
    remaining_today: i32,
    daily_limit: i32,
    has_ai_pack: bool,
}

async fn ai_generate_job_field(
    State(state): State<AppState>,
    auth: AuthUser,
    Json(body): Json<GenerateJobFieldBody>,
) -> impl IntoResponse {
    let company: Option<Uuid> = sqlx::query_scalar(
        "SELECT id FROM company_profiles WHERE user_id = $1"
    )
    .bind(auth.user_id)
    .fetch_optional(&state.pool)
    .await
    .map_err(|e| e.to_string())
    .ok()
    .flatten();

    let Some(company_id) = company else {
        return (StatusCode::FORBIDDEN, Json(serde_json::json!({ "error": "No company profile found" }))).into_response();
    };

    let (has_pack, daily_limit) = {
        let profile_id: Option<Uuid> = sqlx::query_scalar(
            "SELECT id FROM user_role_profiles WHERE user_id = $1 AND role_key = 'COMPANY'"
        )
        .bind(auth.user_id)
        .fetch_optional(&state.pool)
        .await
        .ok()
        .flatten();

        match profile_id {
            Some(pid) => has_active_ai_pack(&state.pool, pid, "COMPANY").await,
            None => (false, BASE_AI_LIMIT),
        }
    };

    let (used, limit) = match check_and_increment_usage(&state.pool, company_id, true, daily_limit).await {
        Ok((u, l)) => (u, l),
        Err(msg) => {
            return (StatusCode::TOO_MANY_REQUESTS, Json(serde_json::json!({ "error": msg }))).into_response();
        }
    };

    let ollama_base = std::env::var("OLLAMA_BASE_URL").unwrap_or_else(|_| "http://ollama.nxtgauge-ai.svc.cluster.local:11434".to_string());
    let model = std::env::var("OLLAMA_CHAT_MODEL").unwrap_or_else(|_| "gemma3:270m".to_string());

    let field_prompt = match body.field.as_str() {
        "title" => format!(
            "Generate a concise, engaging job title (max 80 chars) for: {}. \
             Only return the title, nothing else.",
            body.context
        ),
        "description" => format!(
            "Generate a professional job description with sections: **Summary**, **Key Responsibilities**, **Required Skills**, **Preferred Qualifications**, **What We Offer**. \
             Use markdown formatting. Based on: {}\n\nJob Description:",
            body.context
        ),
        "skills" => format!(
            "List 6-10 relevant skills for this role, as a comma-separated string (no descriptions): {}",
            body.context
        ),
        "category" => format!(
            "Suggest a single job category/department name (max 50 chars) for: {}. Only return the category name.",
            body.context
        ),
        _ => {
            return (StatusCode::BAD_REQUEST, Json(serde_json::json!({ "error": "Invalid field. Use: title, description, skills, category" }))).into_response();
        }
    };

    let generated = match call_ollama_inline(&ollama_base, &model, &field_prompt).await {
        Ok(r) => r.trim().to_string(),
        Err(e) => {
            tracing::error!("Ollama job field generation error: {}", e);
            return (StatusCode::INTERNAL_SERVER_ERROR, Json(serde_json::json!({ "error": "Generation failed" }))).into_response();
        }
    };

    (
        StatusCode::OK,
        Json(GenerateFieldResponse {
            generated_text: generated,
            remaining_today: limit - used,
            daily_limit: limit,
            has_ai_pack: has_pack,
        }),
    ).into_response()
}

// ── Cover Letter Generation (Job Seekers) ──────────────────────────────────────

#[derive(Debug, Deserialize)]
struct CoverLetterBody {
    job_id: Uuid,
    additional_notes: Option<String>,
}

async fn ai_generate_cover_letter(
    State(state): State<AppState>,
    auth: AuthUser,
    Json(body): Json<CoverLetterBody>,
) -> impl IntoResponse {
    let seeker: Option<(Uuid, String, Option<String>, i32, Vec<String>)> = sqlx::query_as(
        "SELECT id, full_name, summary, experience_years, skills FROM job_seeker_profiles WHERE user_id = $1"
    )
    .bind(auth.user_id)
    .fetch_optional(&state.pool)
    .await
    .map_err(|e| e.to_string())
    .ok()
    .and_then(|r| r);

    let Some((seeker_id, full_name, summary, experience, skills)) = seeker else {
        return (StatusCode::FORBIDDEN, Json(serde_json::json!({ "error": "No job seeker profile found" }))).into_response();
    };

    let job: Option<(String, String, String)> = sqlx::query_as(
        "SELECT title, description, location FROM jobs WHERE id = $1"
    )
    .bind(body.job_id)
    .fetch_optional(&state.pool)
    .await
    .map_err(|e| e.to_string())
    .ok()
    .and_then(|r| r);

    let Some((job_title, job_desc, location)) = job else {
        return (StatusCode::NOT_FOUND, Json(serde_json::json!({ "error": "Job not found" }))).into_response();
    };

    let (has_pack, daily_limit) = {
        let profile_id: Option<Uuid> = sqlx::query_scalar(
            "SELECT id FROM user_role_profiles WHERE user_id = $1 AND role_key = 'JOB_SEEKER'"
        )
        .bind(auth.user_id)
        .fetch_optional(&state.pool)
        .await
        .ok()
        .flatten();

        match profile_id {
            Some(pid) => has_active_ai_pack(&state.pool, pid, "JOB_SEEKER").await,
            None => (false, BASE_AI_LIMIT),
        }
    };

    let (used, limit) = match check_and_increment_usage(&state.pool, seeker_id, false, daily_limit).await {
        Ok((u, l)) => (u, l),
        Err(msg) => {
            return (StatusCode::TOO_MANY_REQUESTS, Json(serde_json::json!({ "error": msg }))).into_response();
        }
    };

    let ollama_base = std::env::var("OLLAMA_BASE_URL").unwrap_or_else(|_| "http://ollama.nxtgauge-ai.svc.cluster.local:11434".to_string());
    let model = std::env::var("OLLAMA_CHAT_MODEL").unwrap_or_else(|_| "gemma3:270m".to_string());

    let notes = body.additional_notes.as_deref().unwrap_or("");
    let skills_str = skills.join(", ");

    let prompt = format!(
        "Write a personalized, professional cover letter for a job application.\n\n\
         IMPORTANT: Do NOT include phone number, email, or any contact information. \
         Only use the information provided below. Companies pay to view candidate contact details through the platform.\n\n\
         CANDIDATE INFO:\n\
         Name: {}\n\
         Experience: {} years\n\
         Summary: {}\n\
         Skills: {}\n\
         Notes: {}\n\n\
         JOB INFO:\n\
         Title: {}\n\
         Description: {}\n\
         Location: {}\n\n\
         Write a compelling cover letter that highlights how the candidate's experience and skills match the role. \
         Use a professional tone, 3-4 short paragraphs.",
        full_name, experience, summary.as_deref().unwrap_or("N/A"), skills_str, notes, job_title, job_desc, location
    );

    let generated = match call_ollama_inline(&ollama_base, &model, &prompt).await {
        Ok(r) => r.trim().to_string(),
        Err(e) => {
            tracing::error!("Ollama cover letter generation error: {}", e);
            return (StatusCode::INTERNAL_SERVER_ERROR, Json(serde_json::json!({ "error": "Generation failed" }))).into_response();
        }
    };

    (
        StatusCode::OK,
        Json(GenerateFieldResponse {
            generated_text: generated,
            remaining_today: limit - used,
            daily_limit: limit,
            has_ai_pack: has_pack,
        }),
    ).into_response()
}

// ── Tailor Resume (Job Seekers) ─────────────────────────────────────────────────

#[derive(Debug, Deserialize)]
struct TailorResumeBody {
    job_id: Uuid,
    resume_text: Option<String>,
}

async fn ai_tailor_resume(
    State(state): State<AppState>,
    auth: AuthUser,
    Json(body): Json<TailorResumeBody>,
) -> impl IntoResponse {
    let seeker: Option<(Uuid, String, Option<String>, i32, Vec<String>)> = sqlx::query_as(
        "SELECT id, full_name, summary, experience_years, skills FROM job_seeker_profiles WHERE user_id = $1"
    )
    .bind(auth.user_id)
    .fetch_optional(&state.pool)
    .await
    .map_err(|e| e.to_string())
    .ok()
    .and_then(|r| r);

    let Some((seeker_id, full_name, summary, experience, skills)) = seeker else {
        return (StatusCode::FORBIDDEN, Json(serde_json::json!({ "error": "No job seeker profile found" }))).into_response();
    };

    let job: Option<(String, String)> = sqlx::query_as(
        "SELECT title, description FROM jobs WHERE id = $1"
    )
    .bind(body.job_id)
    .fetch_optional(&state.pool)
    .await
    .map_err(|e| e.to_string())
    .ok()
    .and_then(|r| r);

    let Some((job_title, job_desc)) = job else {
        return (StatusCode::NOT_FOUND, Json(serde_json::json!({ "error": "Job not found" }))).into_response();
    };

    let (has_pack, daily_limit) = {
        let profile_id: Option<Uuid> = sqlx::query_scalar(
            "SELECT id FROM user_role_profiles WHERE user_id = $1 AND role_key = 'JOB_SEEKER'"
        )
        .bind(auth.user_id)
        .fetch_optional(&state.pool)
        .await
        .ok()
        .flatten();

        match profile_id {
            Some(pid) => has_active_ai_pack(&state.pool, pid, "JOB_SEEKER").await,
            None => (false, BASE_AI_LIMIT),
        }
    };

    let (used, limit) = match check_and_increment_usage(&state.pool, seeker_id, false, daily_limit).await {
        Ok((u, l)) => (u, l),
        Err(msg) => {
            return (StatusCode::TOO_MANY_REQUESTS, Json(serde_json::json!({ "error": msg }))).into_response();
        }
    };

    let ollama_base = std::env::var("OLLAMA_BASE_URL").unwrap_or_else(|_| "http://ollama.nxtgauge-ai.svc.cluster.local:11434".to_string());
    let model = std::env::var("OLLAMA_CHAT_MODEL").unwrap_or_else(|_| "gemma3:270m".to_string());

    let existing_resume = body.resume_text.as_deref().unwrap_or("Not provided");
    let skills_str = skills.join(", ");

    let prompt = format!(
        "Rewrite the following resume to better match the target job role. \
         IMPORTANT: Do NOT add phone number, email, or any contact information. \
         Only use the information provided. Companies pay to view candidate contact details through the platform.\n\n\
         CANDIDATE:\n\
         Name: {}\n\
         Experience: {} years\n\
         Summary: {}\n\
         Skills: {}\n\
         Current Resume:\n{}\n\n\
         TARGET JOB:\n\
         Title: {}\n\
         Description: {}\n\n\
         Rewrite the resume to emphasize relevant experience and skills for this role. \
         Keep the same format (bullet points, sections). Do not add contact info.",
        full_name, experience, summary.as_deref().unwrap_or("N/A"), skills_str, existing_resume, job_title, job_desc
    );

    let generated = match call_ollama_inline(&ollama_base, &model, &prompt).await {
        Ok(r) => r.trim().to_string(),
        Err(e) => {
            tracing::error!("Ollama resume tailoring error: {}", e);
            return (StatusCode::INTERNAL_SERVER_ERROR, Json(serde_json::json!({ "error": "Generation failed" }))).into_response();
        }
    };

    (
        StatusCode::OK,
        Json(GenerateFieldResponse {
            generated_text: generated,
            remaining_today: limit - used,
            daily_limit: limit,
            has_ai_pack: has_pack,
        }),
    ).into_response()
}

// ── Auto Apply (Job Seekers) ───────────────────────────────────────────────────

#[derive(Debug, Deserialize)]
struct AutoApplyBody {
    job_ids: Vec<Uuid>,
}

#[derive(Debug, Serialize)]
struct AutoApplyResponse {
    applications_created: i32,
    already_applied: Vec<Uuid>,
    failed: Vec<Uuid>,
    remaining_today: i32,
    daily_limit: i32,
}

async fn ai_auto_apply(
    State(state): State<AppState>,
    auth: AuthUser,
    Json(body): Json<AutoApplyBody>,
) -> impl IntoResponse {
    if body.job_ids.is_empty() || body.job_ids.len() > 10 {
        return (StatusCode::BAD_REQUEST, Json(serde_json::json!({ "error": "Select 1-10 jobs at a time" }))).into_response();
    }

    let seeker: Option<(Uuid, String, Option<String>, i32, Vec<String>)> = sqlx::query_as(
        "SELECT id, full_name, summary, experience_years, skills FROM job_seeker_profiles WHERE user_id = $1"
    )
    .bind(auth.user_id)
    .fetch_optional(&state.pool)
    .await
    .map_err(|e| e.to_string())
    .ok()
    .and_then(|r| r);

    let Some((seeker_id, full_name, summary, experience, skills)) = seeker else {
        return (StatusCode::FORBIDDEN, Json(serde_json::json!({ "error": "No job seeker profile found" }))).into_response();
    };

    if full_name.is_empty() || skills.is_empty() {
        return (StatusCode::BAD_REQUEST, Json(serde_json::json!({ "error": "Complete your profile (name and skills required) before auto-applying" }))).into_response();
    }

    let (has_pack, daily_limit) = {
        let profile_id: Option<Uuid> = sqlx::query_scalar(
            "SELECT id FROM user_role_profiles WHERE user_id = $1 AND role_key = 'JOB_SEEKER'"
        )
        .bind(auth.user_id)
        .fetch_optional(&state.pool)
        .await
        .ok()
        .flatten();

        match profile_id {
            Some(pid) => has_active_ai_pack(&state.pool, pid, "JOB_SEEKER").await,
            None => (false, BASE_AI_LIMIT),
        }
    };

    let remaining = daily_limit - {
        let today = chrono::Utc::now().date_naive();
        let used: Option<i32> = sqlx::query_scalar(
            "SELECT generations_used FROM job_seeker_ai_usage WHERE job_seeker_id = $1 AND usage_date = $2"
        )
        .bind(seeker_id)
        .bind(today)
        .fetch_optional(&state.pool)
        .await
        .ok()
        .flatten();
        used.unwrap_or(0)
    };

    if remaining < body.job_ids.len() as i32 {
        return (StatusCode::TOO_MANY_REQUESTS, Json(serde_json::json!({ "error": format!("Only {} generations left today", remaining) }))).into_response();
    }

    let ollama_base = std::env::var("OLLAMA_BASE_URL").unwrap_or_else(|_| "http://ollama.nxtgauge-ai.svc.cluster.local:11434".to_string());
    let model = std::env::var("OLLAMA_CHAT_MODEL").unwrap_or_else(|_| "gemma3:270m".to_string());
    let skills_str = skills.join(", ");

    let mut created = 0;
    let mut already = vec![];
    let mut failed = vec![];

    for job_id in &body.job_ids {
        let existing: Option<Uuid> = sqlx::query_scalar(
            "SELECT id FROM job_applications WHERE job_id = $1 AND applicant_user_id = $2"
        )
        .bind(job_id)
        .bind(auth.user_id)
        .fetch_optional(&state.pool)
        .await
        .ok()
        .flatten();

        if existing.is_some() {
            already.push(*job_id);
            continue;
        }

        let job: Option<(String, String)> = sqlx::query_as(
            "SELECT title, description FROM jobs WHERE id = $1"
        )
        .bind(job_id)
        .fetch_optional(&state.pool)
        .await
        .ok()
        .and_then(|r| r);

        let Some((job_title, job_desc)) = job else {
            failed.push(*job_id);
            continue;
        };

        let cover_prompt = format!(
            "Write a brief, professional cover letter (max 200 words).\n\n\
             IMPORTANT: Do NOT include phone number, email, or any contact information. \
             Only use the information provided below.\n\n\
             CANDIDATE: Name: {}, Experience: {} years, Skills: {}, Summary: {}\n\
             JOB: Title: {}, Description: {}\n\n\
             Cover Letter:",
            full_name, experience, skills_str, summary.as_deref().unwrap_or(""), job_title, job_desc
        );

        let cover_letter = match call_ollama_inline(&ollama_base, &model, &cover_prompt).await {
            Ok(r) => r.trim().to_string(),
            Err(_) => "I am excited to apply for this position.".to_string(),
        };

        let result = sqlx::query(
            r#"
            INSERT INTO job_applications (job_id, applicant_user_id, cover_letter, applied_via_ai)
            VALUES ($1, $2, $3, true)
            ON CONFLICT (job_id, applicant_user_id) DO NOTHING
            "#
        )
        .bind(job_id)
        .bind(auth.user_id)
        .bind(&cover_letter)
        .execute(&state.pool)
        .await;

        match result {
            Ok(r) => {
                if r.rows_affected() > 0 {
                    created += 1;
                    let _ = check_and_increment_usage(&state.pool, seeker_id, false, daily_limit).await;
                } else {
                    already.push(*job_id);
                }
            }
            Err(_) => {
                failed.push(*job_id);
            }
        }
    }

    let new_remaining = remaining - created;

    (
        StatusCode::OK,
        Json(AutoApplyResponse {
            applications_created: created,
            already_applied: already,
            failed,
            remaining_today: new_remaining.max(0),
            daily_limit,
        }),
    ).into_response()
}

// ── Auto Respond to Lead (Professionals) ───────────────────────────────────────

#[derive(Debug, Deserialize)]
struct AutoRespondToLeadBody {
    lead_id: Uuid,
    profession_key: String,
}

async fn ai_auto_respond_to_lead(
    State(state): State<AppState>,
    auth: AuthUser,
    Json(body): Json<AutoRespondToLeadBody>,
) -> impl IntoResponse {
    let leads_service_url = std::env::var("LEADS_SERVICE_URL")
        .unwrap_or_else(|_| "http://localhost:9118".to_string());

    let profile_id: Option<Uuid> = sqlx::query_scalar(
        "SELECT id FROM user_role_profiles WHERE user_id = $1"
    )
    .bind(auth.user_id)
    .fetch_optional(&state.pool)
    .await
    .map_err(|e| e.to_string())
    .ok()
    .flatten();

    let Some(profile_id) = profile_id else {
        return (StatusCode::FORBIDDEN, Json(serde_json::json!({ "error": "Profile not found" }))).into_response();
    };

    let today = chrono::Utc::now().date_naive();
    let used: Option<i32> = sqlx::query_scalar(
        "SELECT generations_used FROM job_seeker_ai_usage WHERE job_seeker_id = $1 AND usage_date = $2"
    )
    .bind(profile_id)
    .bind(today)
    .fetch_optional(&state.pool)
    .await
    .ok()
    .flatten();

    let daily_limit = 10;
    if used.unwrap_or(0) >= daily_limit {
        return (StatusCode::TOO_MANY_REQUESTS, Json(serde_json::json!({ "error": "Daily AI auto-respond limit reached (10/day)" }))).into_response();
    }

    let url = format!("{}/api/lead-requests/send-ai", leads_service_url.trim_end_matches('/'));
    let client = reqwest::Client::new();
    let payload = serde_json::json!({
        "lead_id": body.lead_id.to_string(),
        "user_id": auth.user_id.to_string(),
        "profession_key": body.profession_key
    });

    let res = client
        .post(&url)
        .json(&payload)
        .send()
        .await
        .map_err(|e| e.to_string());

    let Ok(res) = res else {
        return (StatusCode::BAD_GATEWAY, Json(serde_json::json!({ "error": "Failed to reach leads service" }))).into_response();
    };

    let status = res.status();
    if !status.is_success() {
        let body = res.text().await.unwrap_or_default();
        return (StatusCode::from_u16(status.as_u16()).unwrap_or(StatusCode::BAD_GATEWAY), Json(serde_json::json!({ "error": body }))).into_response();
    }

    let _ = sqlx::query(
        r#"
        INSERT INTO job_seeker_ai_usage (job_seeker_id, usage_date, generations_used)
        VALUES ($1, $2, 1)
        ON CONFLICT (job_seeker_id, usage_date)
        DO UPDATE SET generations_used = job_seeker_ai_usage.generations_used + 1, updated_at = NOW()
        "#
    )
    .bind(profile_id)
    .bind(today)
    .execute(&state.pool)
    .await;

    let remaining = daily_limit - used.unwrap_or(0) - 1;

    (StatusCode::OK, Json(serde_json::json!({
        "success": true,
        "remaining_today": remaining.max(0),
        "daily_limit": daily_limit,
        "message": "AI response sent successfully"
    }))).into_response()
}

// ── Usage Status ───────────────────────────────────────────────────────────────

#[derive(Debug, Serialize)]
struct UsageStatusResponse {
    remaining_today: i32,
    daily_limit: i32,
    has_ai_pack: bool,
}

async fn ai_usage_status(
    State(state): State<AppState>,
    auth: AuthUser,
) -> impl IntoResponse {
    let (is_company, profile_id) = {
        if let Some(cid) = sqlx::query_scalar::<_, Uuid>("SELECT id FROM company_profiles WHERE user_id = $1")
            .bind(auth.user_id)
            .fetch_optional(&state.pool)
            .await
            .ok()
            .flatten()
        {
            (true, cid)
        } else if let Some(sid) = sqlx::query_scalar::<_, Uuid>("SELECT id FROM job_seeker_profiles WHERE user_id = $1")
            .bind(auth.user_id)
            .fetch_optional(&state.pool)
            .await
            .ok()
            .flatten()
        {
            (false, sid)
        } else {
            return (StatusCode::NOT_FOUND, Json(serde_json::json!({ "error": "No profile found" }))).into_response();
        }
    };

    let today = chrono::Utc::now().date_naive();
    let used: Option<i32> = if is_company {
        sqlx::query_scalar("SELECT generations_used FROM company_ai_usage WHERE company_id = $1 AND usage_date = $2")
            .bind(profile_id)
            .bind(today)
            .fetch_optional(&state.pool)
            .await
            .ok()
            .flatten()
    } else {
        sqlx::query_scalar("SELECT generations_used FROM job_seeker_ai_usage WHERE job_seeker_id = $1 AND usage_date = $2")
            .bind(profile_id)
            .bind(today)
            .fetch_optional(&state.pool)
            .await
            .ok()
            .flatten()
    };

    let role_key = if is_company { "COMPANY" } else { "JOB_SEEKER" };
    let (has_pack, daily_limit) = {
        let urp_id: Option<Uuid> = sqlx::query_scalar(
            "SELECT id FROM user_role_profiles WHERE user_id = $1 AND role_key = $2"
        )
        .bind(auth.user_id)
        .bind(role_key)
        .fetch_optional(&state.pool)
        .await
        .ok()
        .flatten();

        match urp_id {
            Some(pid) => has_active_ai_pack(&state.pool, pid, role_key).await,
            None => (false, BASE_AI_LIMIT),
        }
    };

    let remaining = daily_limit - used.unwrap_or(0);

    (StatusCode::OK, Json(UsageStatusResponse {
        remaining_today: remaining.max(0),
        daily_limit,
        has_ai_pack: has_pack,
    })).into_response()
}

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

    #[test]
    fn test_generate_field_request_deserialization() {
        let json = serde_json::json!({
            "field": "title",
            "context": "Senior Rust Developer"
        });
        let body: GenerateJobFieldBody = serde_json::from_value(json).unwrap();
        assert_eq!(body.field, "title");
        assert_eq!(body.context, "Senior Rust Developer");
    }

    #[test]
    fn test_generate_field_request_all_fields() {
        for field in ["title", "description", "skills", "category"] {
            let json = serde_json::json!({
                "field": field,
                "context": "Test context"
            });
            let body: GenerateJobFieldBody = serde_json::from_value(json).unwrap();
            assert_eq!(body.field, field);
        }
    }

    #[test]
    fn test_generate_field_response_serialization() {
        let response = GenerateFieldResponse {
            generated_text: "Senior Rust Developer".to_string(),
            remaining_today: 4,
            daily_limit: 5,
            has_ai_pack: false,
        };
        let json = serde_json::to_value(&response).unwrap();
        assert_eq!(json["generated_text"], "Senior Rust Developer");
        assert_eq!(json["remaining_today"], 4);
        assert_eq!(json["daily_limit"], 5);
        assert_eq!(json["has_ai_pack"], false);
    }

    #[test]
    fn test_generate_field_response_with_ai_pack() {
        let response = GenerateFieldResponse {
            generated_text: "Generated content".to_string(),
            remaining_today: 15,
            daily_limit: 20,
            has_ai_pack: true,
        };
        let json = serde_json::to_value(&response).unwrap();
        assert_eq!(json["has_ai_pack"], true);
        assert_eq!(json["daily_limit"], 20);
    }

    #[test]
    fn test_cover_letter_body_deserialization() {
        let json = serde_json::json!({
            "job_id": "550e8400-e29b-41d4-a716-446655440000",
            "additional_notes": "Available from next month"
        });
        let body: CoverLetterBody = serde_json::from_value(json).unwrap();
        assert_eq!(body.job_id.to_string(), "550e8400-e29b-41d4-a716-446655440000");
        assert_eq!(body.additional_notes, Some("Available from next month".to_string()));
    }

    #[test]
    fn test_cover_letter_body_without_notes() {
        let json = serde_json::json!({
            "job_id": "550e8400-e29b-41d4-a716-446655440000"
        });
        let body: CoverLetterBody = serde_json::from_value(json).unwrap();
        assert_eq!(body.additional_notes, None);
    }

    #[test]
    fn test_tailor_resume_body_deserialization() {
        let json = serde_json::json!({
            "job_id": "550e8400-e29b-41d4-a716-446655440000",
            "resume_text": "My existing resume..."
        });
        let body: TailorResumeBody = serde_json::from_value(json).unwrap();
        assert_eq!(body.job_id.to_string(), "550e8400-e29b-41d4-a716-446655440000");
        assert_eq!(body.resume_text, Some("My existing resume...".to_string()));
    }

    #[test]
    fn test_tailor_resume_body_without_resume() {
        let json = serde_json::json!({
            "job_id": "550e8400-e29b-41d4-a716-446655440000"
        });
        let body: TailorResumeBody = serde_json::from_value(json).unwrap();
        assert_eq!(body.resume_text, None);
    }

    #[test]
    fn test_auto_apply_body_deserialization() {
        let json = serde_json::json!({
            "job_ids": [
                "550e8400-e29b-41d4-a716-446655440000",
                "550e8400-e29b-41d4-a716-446655440001"
            ]
        });
        let body: AutoApplyBody = serde_json::from_value(json).unwrap();
        assert_eq!(body.job_ids.len(), 2);
    }

    #[test]
    fn test_auto_apply_response_serialization() {
        let response = AutoApplyResponse {
            applications_created: 2,
            already_applied: vec![],
            failed: vec![],
            remaining_today: 8,
            daily_limit: 10,
        };
        let json = serde_json::to_value(&response).unwrap();
        assert_eq!(json["applications_created"], 2);
        assert_eq!(json["remaining_today"], 8);
        assert_eq!(json["daily_limit"], 10);
    }

    #[test]
    fn test_usage_status_response_serialization() {
        let response = UsageStatusResponse {
            remaining_today: 3,
            daily_limit: 5,
            has_ai_pack: false,
        };
        let json = serde_json::to_value(&response).unwrap();
        assert_eq!(json["remaining_today"], 3);
        assert_eq!(json["daily_limit"], 5);
        assert_eq!(json["has_ai_pack"], false);
    }

    #[test]
    fn test_base_ai_limit_constant() {
        assert_eq!(BASE_AI_LIMIT, 5);
    }

    #[test]
    fn test_get_ai_limit_from_features_with_value() {
        let features = serde_json::json!({"ai_generations_per_day": 20});
        let limit = get_ai_limit_for_package(&features);
        assert_eq!(limit, 20);
    }

    #[test]
    fn test_get_ai_limit_from_features_defaults_to_base() {
        let features = serde_json::json!({});
        assert_eq!(get_ai_limit_for_package(&features), BASE_AI_LIMIT);

        let features_null = serde_json::json!({"ai_generations_per_day": null});
        assert_eq!(get_ai_limit_for_package(&features_null), BASE_AI_LIMIT);

        let features_wrong_type = serde_json::json!({"ai_generations_per_day": "unlimited"});
        assert_eq!(get_ai_limit_for_package(&features_wrong_type), BASE_AI_LIMIT);
    }

    #[test]
    fn test_invalid_field_error() {
        let json = serde_json::json!({
            "field": "invalid_field",
            "context": "test"
        });
        let body: GenerateJobFieldBody = serde_json::from_value(json).unwrap();
        assert_eq!(body.field, "invalid_field");
    }
}