/**
 * model-snapshots.ts — `model_snapshots` table (active model/provider per repo).
 */
import { getStateDir } from "../../store.js";
import { openStore } from "./utils.js";

/** A captured model/provider snapshot (for cost estimation + dashboard). */
export interface ModelSnapshot {
	provider: string;
	providerName: string | null;
	modelId: string;
	modelName: string | null;
	inputRate: number; // USD per input token
	outputRate: number; // USD per output token
	contextWindow: number;
	maxTokens: number;
	reasoning: boolean;
	capturedAt: number;
}

/** Persist the active model/provider for a repo (latest row wins per repo). */
export function recordModelSnapshot(
	repoRoot: string,
	snap: Omit<ModelSnapshot, "capturedAt">,
	stateDir: string = getStateDir(),
): void {
	const db = openStore(stateDir);
	db.prepare(
		`INSERT INTO model_snapshots
       (repo_root, provider, provider_name, model_id, model_name, input_rate,
        output_rate, context_window, max_tokens, reasoning, captured_at)
     VALUES (@repo_root, @provider, @provider_name, @model_id, @model_name,
             @input_rate, @output_rate, @context_window, @max_tokens, @reasoning, @captured_at)`,
	).run({
		repo_root: repoRoot,
		provider: snap.provider,
		provider_name: snap.providerName,
		model_id: snap.modelId,
		model_name: snap.modelName,
		input_rate: snap.inputRate,
		output_rate: snap.outputRate,
		context_window: snap.contextWindow,
		max_tokens: snap.maxTokens,
		reasoning: snap.reasoning ? 1 : 0,
		captured_at: Date.now(),
	});
}

/** Most recent model/provider snapshot for a repo, or undefined. */
export function latestModelSnapshot(
	stateDir: string = getStateDir(),
): ModelSnapshot | undefined {
	const db = openStore(stateDir);
	const row = db
		.prepare(`SELECT * FROM model_snapshots ORDER BY captured_at DESC LIMIT 1`)
		.get() as
		| {
				repo_root: string;
				provider: string;
				provider_name: string | null;
				model_id: string;
				model_name: string | null;
				input_rate: number;
				output_rate: number;
				context_window: number;
				max_tokens: number;
				reasoning: number;
				captured_at: number;
		  }
		| undefined;
	if (!row) return undefined;
	return {
		provider: row.provider,
		providerName: row.provider_name,
		modelId: row.model_id,
		modelName: row.model_name,
		inputRate: row.input_rate,
		outputRate: row.output_rate,
		contextWindow: row.context_window,
		maxTokens: row.max_tokens,
		reasoning: row.reasoning === 1,
		capturedAt: row.captured_at,
	};
}

/** All model snapshots (for the dashboard Thresholds table — deduped by
 *  caller). Returns NULL columns as-is; callers should default missing
 *  context_window/max_tokens to 0. */
export function listModelSnapshots(
	stateDir: string = getStateDir(),
): ModelSnapshot[] {
	const db = openStore(stateDir);
	const rows = db
		.prepare(`SELECT * FROM model_snapshots ORDER BY captured_at DESC`)
		.all() as Array<{
		repo_root: string;
		provider: string;
		provider_name: string | null;
		model_id: string;
		model_name: string | null;
		input_rate: number;
		output_rate: number;
		context_window: number;
		max_tokens: number;
		reasoning: number;
		captured_at: number;
	}>;
	return rows.map((row) => ({
		provider: row.provider,
		providerName: row.provider_name,
		modelId: row.model_id,
		modelName: row.model_name,
		inputRate: row.input_rate,
		outputRate: row.output_rate,
		contextWindow: row.context_window,
		maxTokens: row.max_tokens,
		reasoning: row.reasoning === 1,
		capturedAt: row.captured_at,
	}));
}