//! Admin provider model and request/response types.
//!
//! Represents the admin-curated catalog of LLM providers and their models.
//! Users select from this catalog when configuring their settings.

use chrono::{DateTime, Utc};
use serde::{Deserialize, Serialize};
use uuid::Uuid;

/// A single model within a provider's model list (stored as JSONB).
#[derive(Debug, Clone, Serialize, Deserialize, PartialEq)]
pub struct ProviderModel {
    pub model_id: String,
    pub display_name: String,
    #[serde(default)]
    pub is_default: bool,
}

/// An admin provider record from the database.
#[derive(Debug, Clone, Serialize)]
pub struct AdminProvider {
    pub id: Uuid,
    pub provider_name: String,
    pub display_name: String,
    pub models_scraping: Vec<ProviderModel>,
    pub models_websearch: Vec<ProviderModel>,
    pub is_enabled: bool,
    pub created_at: DateTime<Utc>,
    pub updated_at: DateTime<Utc>,
}

/// Request body for `POST /api/v1/admin/providers` (create or update).
#[derive(Debug, Deserialize)]
pub struct CreateProviderRequest {
    pub provider_name: String,
    pub display_name: String,
    pub models_scraping: Vec<ProviderModel>,
    pub models_websearch: Vec<ProviderModel>,
    #[serde(default = "default_true")]
    pub is_enabled: bool,
}

fn default_true() -> bool {
    true
}

/// Known provider names.
///
/// Also used by `models::api_key` for validating user API key requests.
pub const VALID_PROVIDERS: &[&str] = &["gemini", "openai", "anthropic"];

/// Valid provider names for user API key storage (includes non-LLM services).
pub const VALID_API_KEY_PROVIDERS: &[&str] = &["gemini", "openai", "anthropic", "brave_search"];

impl CreateProviderRequest {
    /// Validate the provider creation request.
    ///
    /// Returns `Ok(())` if all fields are valid, or `Err(message)`
    /// describing the first validation failure.
    pub fn validate(&self) -> Result<(), String> {
        let name = self.provider_name.trim();
        if name.is_empty() {
            return Err("Provider name cannot be empty".into());
        }
        if name.len() > 50 {
            return Err("Provider name must be at most 50 characters".into());
        }
        if !VALID_PROVIDERS.contains(&name) {
            return Err(format!(
                "Invalid provider name '{}'. Must be one of: {}",
                name,
                VALID_PROVIDERS.join(", ")
            ));
        }

        validate_display_name(&self.display_name)?;
        validate_models(&self.models_scraping)?;
        validate_models(&self.models_websearch)?;

        Ok(())
    }
}

/// Request body for updating an existing provider.
#[derive(Debug, Deserialize)]
pub struct UpdateProviderRequest {
    pub display_name: Option<String>,
    pub models_scraping: Option<Vec<ProviderModel>>,
    pub models_websearch: Option<Vec<ProviderModel>>,
    pub is_enabled: Option<bool>,
}

impl UpdateProviderRequest {
    /// Validate the provider update request.
    pub fn validate(&self) -> Result<(), String> {
        if let Some(ref display) = self.display_name {
            validate_display_name(display)?;
        }
        if let Some(ref models) = self.models_scraping {
            validate_models(models)?;
        }
        if let Some(ref models) = self.models_websearch {
            validate_models(models)?;
        }
        Ok(())
    }
}

/// Validate a provider display name.
fn validate_display_name(display_name: &str) -> Result<(), String> {
    if display_name.trim().is_empty() {
        return Err("Display name cannot be empty".into());
    }
    if display_name.len() > 100 {
        return Err("Display name must be at most 100 characters".into());
    }
    Ok(())
}

/// Validate a list of provider models.
fn validate_models(models: &[ProviderModel]) -> Result<(), String> {
    if models.is_empty() {
        return Err("At least one model must be provided".into());
    }

    let default_count = models.iter().filter(|m| m.is_default).count();
    if default_count > 1 {
        return Err("At most one model can be marked as default".into());
    }

    for model in models {
        if model.model_id.trim().is_empty() {
            return Err("Model ID cannot be empty".into());
        }
        if model.model_id.len() > 100 {
            return Err("Model ID must be at most 100 characters".into());
        }
        if model.display_name.trim().is_empty() {
            return Err("Model display name cannot be empty".into());
        }
        if model.display_name.len() > 200 {
            return Err("Model display name must be at most 200 characters".into());
        }
    }

    Ok(())
}

/// Public response for enabled providers (no admin-only data).
///
/// Returned by `GET /api/v1/config/providers` for authenticated (non-admin) users.
#[derive(Debug, Serialize)]
pub struct ProviderConfigResponse {
    pub provider_name: String,
    pub display_name: String,
    pub models_scraping: Vec<PublicModelInfo>,
    pub models_websearch: Vec<PublicModelInfo>,
}

/// Public model info (subset of `ProviderModel`).
#[derive(Debug, Serialize)]
pub struct PublicModelInfo {
    pub model_id: String,
    pub display_name: String,
    pub is_default: bool,
}

impl From<ProviderModel> for PublicModelInfo {
    fn from(m: ProviderModel) -> Self {
        Self {
            model_id: m.model_id,
            display_name: m.display_name,
            is_default: m.is_default,
        }
    }
}

/// Full admin response for a provider (includes all fields).
#[derive(Debug, Serialize)]
pub struct AdminProviderResponse {
    pub id: Uuid,
    pub provider_name: String,
    pub display_name: String,
    pub models_scraping: Vec<ProviderModel>,
    pub models_websearch: Vec<ProviderModel>,
    pub is_enabled: bool,
    pub created_at: DateTime<Utc>,
    pub updated_at: DateTime<Utc>,
}

impl From<AdminProvider> for AdminProviderResponse {
    fn from(p: AdminProvider) -> Self {
        Self {
            id: p.id,
            provider_name: p.provider_name,
            display_name: p.display_name,
            models_scraping: p.models_scraping,
            models_websearch: p.models_websearch,
            is_enabled: p.is_enabled,
            created_at: p.created_at,
            updated_at: p.updated_at,
        }
    }
}

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

    /// Helper to create a sample model list for tests.
    fn sample_models() -> Vec<ProviderModel> {
        vec![ProviderModel {
            model_id: "m1".into(),
            display_name: "Model 1".into(),
            is_default: true,
        }]
    }

    #[test]
    fn test_valid_create_request() {
        let req = CreateProviderRequest {
            provider_name: "gemini".into(),
            display_name: "Google Gemini".into(),
            models_scraping: vec![ProviderModel {
                model_id: "gemini-2.5-pro".into(),
                display_name: "Gemini 2.5 Pro".into(),
                is_default: true,
            }],
            models_websearch: vec![ProviderModel {
                model_id: "gemini-2.5-pro".into(),
                display_name: "Gemini 2.5 Pro".into(),
                is_default: true,
            }],
            is_enabled: true,
        };
        assert!(req.validate().is_ok());
    }

    #[test]
    fn test_invalid_provider_name() {
        let req = CreateProviderRequest {
            provider_name: "unknown_provider".into(),
            display_name: "Unknown".into(),
            models_scraping: sample_models(),
            models_websearch: sample_models(),
            is_enabled: true,
        };
        let err = req.validate().unwrap_err();
        assert!(err.contains("Invalid provider name"));
    }

    #[test]
    fn test_empty_provider_name() {
        let req = CreateProviderRequest {
            provider_name: "  ".into(),
            display_name: "Some Provider".into(),
            models_scraping: sample_models(),
            models_websearch: sample_models(),
            is_enabled: true,
        };
        let err = req.validate().unwrap_err();
        assert!(err.contains("cannot be empty"));
    }

    #[test]
    fn test_empty_models_scraping_list() {
        let req = CreateProviderRequest {
            provider_name: "openai".into(),
            display_name: "OpenAI".into(),
            models_scraping: vec![],
            models_websearch: sample_models(),
            is_enabled: true,
        };
        let err = req.validate().unwrap_err();
        assert!(err.contains("At least one model"));
    }

    #[test]
    fn test_empty_models_websearch_list() {
        let req = CreateProviderRequest {
            provider_name: "openai".into(),
            display_name: "OpenAI".into(),
            models_scraping: sample_models(),
            models_websearch: vec![],
            is_enabled: true,
        };
        let err = req.validate().unwrap_err();
        assert!(err.contains("At least one model"));
    }

    #[test]
    fn test_multiple_defaults_rejected() {
        let req = CreateProviderRequest {
            provider_name: "openai".into(),
            display_name: "OpenAI".into(),
            models_scraping: vec![
                ProviderModel {
                    model_id: "gpt-4o".into(),
                    display_name: "GPT-4o".into(),
                    is_default: true,
                },
                ProviderModel {
                    model_id: "gpt-4o-mini".into(),
                    display_name: "GPT-4o Mini".into(),
                    is_default: true,
                },
            ],
            models_websearch: sample_models(),
            is_enabled: true,
        };
        let err = req.validate().unwrap_err();
        assert!(err.contains("At most one model"));
    }

    #[test]
    fn test_empty_model_id_rejected() {
        let req = CreateProviderRequest {
            provider_name: "anthropic".into(),
            display_name: "Anthropic".into(),
            models_scraping: vec![ProviderModel {
                model_id: "".into(),
                display_name: "Claude".into(),
                is_default: false,
            }],
            models_websearch: sample_models(),
            is_enabled: true,
        };
        let err = req.validate().unwrap_err();
        assert!(err.contains("Model ID cannot be empty"));
    }

    #[test]
    fn test_update_request_all_none() {
        let req = UpdateProviderRequest {
            display_name: None,
            models_scraping: None,
            models_websearch: None,
            is_enabled: None,
        };
        assert!(req.validate().is_ok());
    }

    #[test]
    fn test_update_request_empty_display_name() {
        let req = UpdateProviderRequest {
            display_name: Some("".into()),
            models_scraping: None,
            models_websearch: None,
            is_enabled: None,
        };
        let err = req.validate().unwrap_err();
        assert!(err.contains("Display name cannot be empty"));
    }

    #[test]
    fn test_provider_model_deserialization() {
        let json = r#"{"model_id": "gpt-4o", "display_name": "GPT-4o"}"#;
        let model: ProviderModel = serde_json::from_str(json).unwrap();
        assert_eq!(model.model_id, "gpt-4o");
        assert!(!model.is_default); // default is false
    }
}