mkt-google 0.3.0

//! [`MarketingProvider`] implementation for Google Ads.

use mkt_core::error::{MktError, Result};
use mkt_core::models::{
    Campaign, CampaignFilters, CampaignId, CreateCampaignInput, InsightsQuery, InsightsReport,
    Paginated, ProviderHealth, UpdateCampaignInput,
};
use mkt_core::provider::{MarketingProvider, ProviderCapabilities};
use tracing::instrument;

use crate::client::GoogleClient;

/// Upper bound on insights pages fetched per query (defense against
/// runaway cursors; each page holds thousands of rows).
const MAX_PAGES: usize = 100;
use crate::mapping;

/// Google Ads marketing provider.
///
/// Wraps a [`GoogleClient`] and implements [`MarketingProvider`] using the
/// Google Ads REST API: GAQL for reads, `:mutate` endpoints for writes.
#[derive(Debug)]
pub struct GoogleProvider {
    client: GoogleClient,
}

impl GoogleProvider {
    /// Create a new Google Ads provider.
    pub const fn new(client: GoogleClient) -> Self {
        Self { client }
    }

    /// Fetch one campaign by numeric ID via GAQL.
    async fn fetch_campaign(&self, id: &str) -> Result<Campaign> {
        let query = format!(
            "SELECT {} FROM campaign WHERE campaign.id = {id}",
            mapping::CAMPAIGN_GAQL_FIELDS
        );
        let resp = self.client.search(&query).await?;
        let row = resp["results"]
            .as_array()
            .and_then(|rows| rows.first())
            .ok_or_else(|| MktError::ApiError {
                provider: "google".into(),
                status: 404,
                message: format!("campaign {id} not found"),
                retry_after: None,
            })?;
        mapping::google_row_to_campaign(row)
    }
}

impl MarketingProvider for GoogleProvider {
    fn name(&self) -> &'static str {
        "google"
    }

    fn display_name(&self) -> &'static str {
        "Google Ads"
    }

    fn capabilities(&self) -> ProviderCapabilities {
        ProviderCapabilities {
            campaigns: true,
            adsets: false,
            ads: false,
            creatives: false,
            audiences: false,
            insights: true,
            organic_posts: false,
            dark_posts: false,
            video_upload: false,
            image_upload: false,
            workflow_templates: false,
        }
    }

    // ── Campaigns ──────────────────────────────────────

    #[instrument(skip(self))]
    fn list_campaigns(
        &self,
        filters: &CampaignFilters,
    ) -> impl std::future::Future<Output = Result<Paginated<Campaign>>> + Send {
        async move {
            let mut query = format!("SELECT {} FROM campaign", mapping::CAMPAIGN_GAQL_FIELDS);

            let mut conditions: Vec<String> = Vec::new();
            if let Some(status) = &filters.status {
                conditions.push(format!(
                    "campaign.status = '{}'",
                    mapping::domain_status_to_google(status)
                ));
            }
            if let Some(name) = &filters.name_contains {
                // GAQL LIKE: quotes escaped, %/_/[ neutralized so user
                // input matches literally.
                let escaped = mapping::escape_gaql_like(name);
                conditions.push(format!("campaign.name LIKE '%{escaped}%'"));
            }
            if !conditions.is_empty() {
                query.push_str(" WHERE ");
                query.push_str(&conditions.join(" AND "));
            }
            if let Some(limit) = filters.limit {
                query = format!("{query} LIMIT {limit}");
            }

            let resp = self
                .client
                .search_page(&query, filters.cursor.as_deref())
                .await?;

            let items = resp["results"]
                .as_array()
                .unwrap_or(&Vec::new())
                .iter()
                .map(mapping::google_row_to_campaign)
                .collect::<Result<Vec<_>>>()?;

            let next_cursor = resp["nextPageToken"].as_str().map(String::from);

            Ok(Paginated {
                data: items,
                next_cursor,
                total: None,
            })
        }
    }

    #[instrument(skip(self))]
    fn get_campaign(
        &self,
        id: &CampaignId,
    ) -> impl std::future::Future<Output = Result<Campaign>> + Send {
        async move { self.fetch_campaign(&id.0).await }
    }

    #[instrument(skip(self, input))]
    fn create_campaign(
        &self,
        input: &CreateCampaignInput,
    ) -> impl std::future::Future<Output = Result<Campaign>> + Send {
        async move {
            // Budget and campaign go out in ONE atomic googleAds:mutate
            // request: the budget is created under a temporary negative ID
            // and referenced by the campaign, so a campaign failure can no
            // longer leave an orphaned budget behind.
            let ops = mapping::atomic_create_operations(input, self.client.customer_id())?;
            let resp = self.client.mutate_atomic(&ops).await?;
            let new_id = mapping::campaign_id_from_atomic_mutate(&resp)?;

            self.fetch_campaign(&new_id).await
        }
    }

    #[instrument(skip(self, input))]
    fn update_campaign(
        &self,
        id: &CampaignId,
        input: &UpdateCampaignInput,
    ) -> impl std::future::Future<Output = Result<Campaign>> + Send {
        async move {
            let ops = mapping::campaign_update_operation(self.client.customer_id(), &id.0, input);
            let _resp = self.client.mutate("campaigns", &ops).await?;
            self.fetch_campaign(&id.0).await
        }
    }

    #[instrument(skip(self))]
    fn delete_campaign(
        &self,
        id: &CampaignId,
    ) -> impl std::future::Future<Output = Result<()>> + Send {
        async move {
            let resource = mapping::campaign_resource_name(self.client.customer_id(), &id.0);
            let ops = serde_json::json!([{ "remove": resource }]);
            let _resp = self.client.mutate("campaigns", &ops).await?;
            Ok(())
        }
    }

    // ── Insights ─────────────────────────────────────────

    #[instrument(skip(self, query))]
    fn get_insights(
        &self,
        query: &InsightsQuery,
    ) -> impl std::future::Future<Output = Result<InsightsReport>> + Send {
        async move {
            let metrics = if query.metrics.is_empty() {
                "metrics.impressions, metrics.clicks, metrics.cost_micros, metrics.ctr".to_string()
            } else {
                query
                    .metrics
                    .iter()
                    .map(|m| format!("metrics.{m}"))
                    .collect::<Vec<_>>()
                    .join(", ")
            };

            let gaql = format!(
                "SELECT campaign.id, campaign.name, segments.date, {metrics} FROM campaign"
            );

            // GAQL requires a finite date range whenever a core date
            // segment is selected, so an unbounded query must not be sent.
            let gaql = query.date_range.as_ref().map_or_else(
                || format!("{gaql} WHERE segments.date DURING LAST_30_DAYS"),
                |range| {
                    format!(
                        "{gaql} WHERE segments.date BETWEEN '{}' AND '{}'",
                        range.start.format("%Y-%m-%d"),
                        range.end.format("%Y-%m-%d")
                    )
                },
            );

            // Aggregate every page: a truncated report silently loses
            // spend data. Page count is bounded by the API's 10k rows/page.
            let mut report: Option<InsightsReport> = None;
            let mut page_token: Option<String> = None;
            for _ in 0..MAX_PAGES {
                let resp = self
                    .client
                    .search_page(&gaql, page_token.as_deref())
                    .await?;
                let page = mapping::google_insights_to_domain(&resp)?;
                report = Some(match report.take() {
                    None => page,
                    Some(mut acc) => {
                        acc.rows.extend(page.rows);
                        acc
                    }
                });
                page_token = resp["nextPageToken"].as_str().map(String::from);
                if page_token.is_none() {
                    break;
                }
            }
            report.ok_or_else(|| MktError::ApiError {
                provider: "google".into(),
                status: 0,
                message: "insights search returned no pages".into(),
                retry_after: None,
            })
        }
    }

    // ── Health check ───────────────────────────────────

    async fn health_check(&self) -> Result<ProviderHealth> {
        let start = std::time::Instant::now();
        let result = self
            .client
            .search("SELECT customer.id FROM customer LIMIT 1")
            .await;
        #[allow(clippy::cast_possible_truncation)] // health-check latency fits in u64
        let latency = start.elapsed().as_millis() as u64;

        match result {
            Ok(_) => Ok(ProviderHealth {
                provider: "google".into(),
                healthy: true,
                latency_ms: latency,
                message: None,
            }),
            Err(e) => Ok(ProviderHealth {
                provider: "google".into(),
                healthy: false,
                latency_ms: latency,
                message: Some(e.to_string()),
            }),
        }
    }
}