import { NodeOAuthClient, type ClientMetadata } from "@atproto/oauth-client-node";
import { SQL } from "bun";
import { JoseKey } from "@atproto/jwk-jose";
import { BASE_HOST } from "./constants";

export const db = new SQL(
    process.env.NODE_ENV === 'production'
        ? process.env.DATABASE_URL || (() => {
            throw new Error('DATABASE_URL environment variable is required in production');
          })()
        : process.env.DATABASE_URL || "postgres://postgres:postgres@localhost:5432/wisp"
);

await db`
    CREATE TABLE IF NOT EXISTS oauth_states (
        key TEXT PRIMARY KEY,
        data TEXT NOT NULL,
        created_at BIGINT DEFAULT EXTRACT(EPOCH FROM NOW())
    )
`;

await db`
    CREATE TABLE IF NOT EXISTS oauth_sessions (
        sub TEXT PRIMARY KEY,
        data TEXT NOT NULL,
        updated_at BIGINT DEFAULT EXTRACT(EPOCH FROM NOW()),
        expires_at BIGINT NOT NULL DEFAULT EXTRACT(EPOCH FROM NOW()) + 2592000
    )
`;

await db`
    CREATE TABLE IF NOT EXISTS oauth_keys (
        kid TEXT PRIMARY KEY,
        jwk TEXT NOT NULL,
        created_at BIGINT DEFAULT EXTRACT(EPOCH FROM NOW())
    )
`;

// Domains table maps subdomain -> DID
await db`
    CREATE TABLE IF NOT EXISTS domains (
        domain TEXT PRIMARY KEY,
        did TEXT UNIQUE NOT NULL,
        rkey TEXT,
        created_at BIGINT DEFAULT EXTRACT(EPOCH FROM NOW())
    )
`;

// Add columns if they don't exist (for existing databases)
try {
    await db`ALTER TABLE domains ADD COLUMN IF NOT EXISTS rkey TEXT`;
} catch (err) {
    // Column might already exist, ignore
}

try {
    await db`ALTER TABLE oauth_sessions ADD COLUMN IF NOT EXISTS expires_at BIGINT NOT NULL DEFAULT EXTRACT(EPOCH FROM NOW()) + 2592000`;
} catch (err) {
    // Column might already exist, ignore
}

try {
    await db`ALTER TABLE oauth_keys ADD COLUMN IF NOT EXISTS created_at BIGINT DEFAULT EXTRACT(EPOCH FROM NOW())`;
} catch (err) {
    // Column might already exist, ignore
}

try {
    await db`ALTER TABLE oauth_states ADD COLUMN IF NOT EXISTS expires_at BIGINT DEFAULT EXTRACT(EPOCH FROM NOW()) + 3600`;
} catch (err) {
    // Column might already exist, ignore
}

// Custom domains table for BYOD (bring your own domain)
await db`
    CREATE TABLE IF NOT EXISTS custom_domains (
        id TEXT PRIMARY KEY,
        domain TEXT UNIQUE NOT NULL,
        did TEXT NOT NULL,
        rkey TEXT,
        verified BOOLEAN DEFAULT false,
        last_verified_at BIGINT,
        created_at BIGINT DEFAULT EXTRACT(EPOCH FROM NOW())
    )
`;

// Migrate existing tables to make rkey nullable and remove default
try {
    await db`ALTER TABLE custom_domains ALTER COLUMN rkey DROP NOT NULL`;
} catch (err) {
    // Column might already be nullable, ignore
}
try {
    await db`ALTER TABLE custom_domains ALTER COLUMN rkey DROP DEFAULT`;
} catch (err) {
    // Default might already be removed, ignore
}

// Sites table - cache of place.wisp.fs records from PDS
await db`
    CREATE TABLE IF NOT EXISTS sites (
        did TEXT NOT NULL,
        rkey TEXT NOT NULL,
        display_name TEXT,
        created_at BIGINT DEFAULT EXTRACT(EPOCH FROM NOW()),
        updated_at BIGINT DEFAULT EXTRACT(EPOCH FROM NOW()),
        PRIMARY KEY (did, rkey)
    )
`;

const RESERVED_HANDLES = new Set([
    "www",
    "api",
    "admin",
    "static",
    "public",
    "preview"
]);

export const isValidHandle = (handle: string): boolean => {
    const h = handle.trim().toLowerCase();
    if (h.length < 3 || h.length > 63) return false;
    if (!/^[a-z0-9-]+$/.test(h)) return false;
    if (h.startsWith('-') || h.endsWith('-')) return false;
    if (h.includes('--')) return false;
    if (RESERVED_HANDLES.has(h)) return false;
    return true;
};

export const toDomain = (handle: string): string => `${handle.toLowerCase()}.${BASE_HOST}`;

export const getDomainByDid = async (did: string): Promise<string | null> => {
    const rows = await db`SELECT domain FROM domains WHERE did = ${did}`;
    return rows[0]?.domain ?? null;
};

export const getWispDomainInfo = async (did: string) => {
    const rows = await db`SELECT domain, rkey FROM domains WHERE did = ${did}`;
    return rows[0] ?? null;
};

export const getDidByDomain = async (domain: string): Promise<string | null> => {
    const rows = await db`SELECT did FROM domains WHERE domain = ${domain.toLowerCase()}`;
    return rows[0]?.did ?? null;
};

export const isDomainAvailable = async (handle: string): Promise<boolean> => {
    const h = handle.trim().toLowerCase();
    if (!isValidHandle(h)) return false;
    const domain = toDomain(h);
    const rows = await db`SELECT 1 FROM domains WHERE domain = ${domain} LIMIT 1`;
    return rows.length === 0;
};

export const isDomainRegistered = async (domain: string) => {
    const domainLower = domain.toLowerCase().trim();

    // Check wisp.place subdomains
    const wispDomain = await db`
        SELECT did, domain, rkey FROM domains WHERE domain = ${domainLower}
    `;

    if (wispDomain.length > 0) {
        return {
            registered: true,
            type: 'wisp' as const,
            domain: wispDomain[0].domain,
            did: wispDomain[0].did,
            rkey: wispDomain[0].rkey
        };
    }

    // Check custom domains
    const customDomain = await db`
        SELECT id, domain, did, rkey, verified FROM custom_domains WHERE domain = ${domainLower}
    `;

    if (customDomain.length > 0) {
        return {
            registered: true,
            type: 'custom' as const,
            domain: customDomain[0].domain,
            did: customDomain[0].did,
            rkey: customDomain[0].rkey,
            verified: customDomain[0].verified
        };
    }

    return { registered: false };
};

export const claimDomain = async (did: string, handle: string): Promise<string> => {
    const h = handle.trim().toLowerCase();
    if (!isValidHandle(h)) throw new Error('invalid_handle');
    const domain = toDomain(h);
    try {
        await db`
            INSERT INTO domains (domain, did)
            VALUES (${domain}, ${did})
        `;
    } catch (err) {
        // Unique constraint violations -> already taken or DID already claimed
        throw new Error('conflict');
    }
    return domain;
};

export const updateDomain = async (did: string, handle: string): Promise<string> => {
    const h = handle.trim().toLowerCase();
    if (!isValidHandle(h)) throw new Error('invalid_handle');
    const domain = toDomain(h);
    try {
        const rows = await db`
            UPDATE domains SET domain = ${domain}
            WHERE did = ${did}
            RETURNING domain
        `;
        if (rows.length > 0) return rows[0].domain as string;
        // No existing row, behave like claim
        return await claimDomain(did, handle);
    } catch (err) {
        // Unique constraint violations -> already taken by someone else
        throw new Error('conflict');
    }
};

export const updateWispDomainSite = async (did: string, siteRkey: string | null): Promise<void> => {
    await db`
        UPDATE domains
        SET rkey = ${siteRkey}
        WHERE did = ${did}
    `;
};

export const getWispDomainSite = async (did: string): Promise<string | null> => {
    const rows = await db`SELECT rkey FROM domains WHERE did = ${did}`;
    return rows[0]?.rkey ?? null;
};

// Session timeout configuration (30 days in seconds)
const SESSION_TIMEOUT = 30 * 24 * 60 * 60; // 2592000 seconds
// OAuth state timeout (1 hour in seconds)
const STATE_TIMEOUT = 60 * 60; // 3600 seconds

const stateStore = {
    async set(key: string, data: any) {
        console.debug('[stateStore] set', key)
        const expiresAt = Math.floor(Date.now() / 1000) + STATE_TIMEOUT;
        await db`
            INSERT INTO oauth_states (key, data, created_at, expires_at)
            VALUES (${key}, ${JSON.stringify(data)}, EXTRACT(EPOCH FROM NOW()), ${expiresAt})
            ON CONFLICT (key) DO UPDATE SET data = EXCLUDED.data, expires_at = ${expiresAt}
        `;
    },
    async get(key: string) {
        console.debug('[stateStore] get', key)
        const now = Math.floor(Date.now() / 1000);
        const result = await db`
            SELECT data, expires_at
            FROM oauth_states
            WHERE key = ${key}
        `;
        if (!result[0]) return undefined;

        // Check if expired
        const expiresAt = Number(result[0].expires_at);
        if (expiresAt && now > expiresAt) {
            console.debug('[stateStore] State expired, deleting', key);
            await db`DELETE FROM oauth_states WHERE key = ${key}`;
            return undefined;
        }

        return JSON.parse(result[0].data);
    },
    async del(key: string) {
        console.debug('[stateStore] del', key)
        await db`DELETE FROM oauth_states WHERE key = ${key}`;
    }
};

const sessionStore = {
    async set(sub: string, data: any) {
        console.debug('[sessionStore] set', sub)
        const expiresAt = Math.floor(Date.now() / 1000) + SESSION_TIMEOUT;
        await db`
            INSERT INTO oauth_sessions (sub, data, updated_at, expires_at)
            VALUES (${sub}, ${JSON.stringify(data)}, EXTRACT(EPOCH FROM NOW()), ${expiresAt})
            ON CONFLICT (sub) DO UPDATE SET
                data = EXCLUDED.data,
                updated_at = EXTRACT(EPOCH FROM NOW()),
                expires_at = ${expiresAt}
        `;
    },
    async get(sub: string) {
        console.debug('[sessionStore] get', sub)
        const now = Math.floor(Date.now() / 1000);
        const result = await db`
            SELECT data, expires_at
            FROM oauth_sessions
            WHERE sub = ${sub}
        `;
        if (!result[0]) return undefined;

        // Check if expired
        const expiresAt = Number(result[0].expires_at);
        if (expiresAt && now > expiresAt) {
            console.log('[sessionStore] Session expired, deleting', sub);
            await db`DELETE FROM oauth_sessions WHERE sub = ${sub}`;
            return undefined;
        }

        return JSON.parse(result[0].data);
    },
    async del(sub: string) {
        console.debug('[sessionStore] del', sub)
        await db`DELETE FROM oauth_sessions WHERE sub = ${sub}`;
    }
};

export { sessionStore };

// Cleanup expired sessions and states
export const cleanupExpiredSessions = async () => {
    const now = Math.floor(Date.now() / 1000);
    try {
        const sessionsDeleted = await db`
            DELETE FROM oauth_sessions WHERE expires_at < ${now}
        `;
        const statesDeleted = await db`
            DELETE FROM oauth_states WHERE expires_at IS NOT NULL AND expires_at < ${now}
        `;
        console.log(`[Cleanup] Deleted ${sessionsDeleted.length} expired sessions and ${statesDeleted.length} expired states`);
        return { sessions: sessionsDeleted.length, states: statesDeleted.length };
    } catch (err) {
        console.error('[Cleanup] Failed to cleanup expired data:', err);
        return { sessions: 0, states: 0 };
    }
};

export const createClientMetadata = (config: { domain: `http://${string}` | `https://${string}`, clientName: string }): ClientMetadata => {
    const isLocalDev = process.env.LOCAL_DEV === 'true';

    if (isLocalDev) {
        // Loopback client for local development
        // For loopback, scopes and redirect_uri must be in client_id query string
        const redirectUri = 'http://127.0.0.1:8000/api/auth/callback';
        const scope = 'atproto transition:generic';
        const params = new URLSearchParams();
        params.append('redirect_uri', redirectUri);
        params.append('scope', scope);

        return {
            client_id: `http://localhost?${params.toString()}`,
            client_name: config.clientName,
            client_uri: config.domain,
            redirect_uris: [redirectUri],
            grant_types: ['authorization_code', 'refresh_token'],
            response_types: ['code'],
            application_type: 'web',
            token_endpoint_auth_method: 'none',
            scope: scope,
            dpop_bound_access_tokens: false,
            subject_type: 'public'
        };
    }

    // Production client with private_key_jwt
    return {
        client_id: `${config.domain}/client-metadata.json`,
        client_name: config.clientName,
        client_uri: config.domain,
        logo_uri: `${config.domain}/logo.png`,
        tos_uri: `${config.domain}/tos`,
        policy_uri: `${config.domain}/policy`,
        redirect_uris: [`${config.domain}/api/auth/callback`],
        grant_types: ['authorization_code', 'refresh_token'],
        response_types: ['code'],
        application_type: 'web',
        token_endpoint_auth_method: 'private_key_jwt',
        token_endpoint_auth_signing_alg: "ES256",
        scope: "atproto transition:generic",
        dpop_bound_access_tokens: true,
        jwks_uri: `${config.domain}/jwks.json`,
        subject_type: 'public',
        authorization_signed_response_alg: 'ES256'
    };
};

const persistKey = async (key: JoseKey) => {
    const priv = key.privateJwk;
    if (!priv) return;
    const kid = key.kid ?? crypto.randomUUID();
    await db`
        INSERT INTO oauth_keys (kid, jwk, created_at)
        VALUES (${kid}, ${JSON.stringify(priv)}, EXTRACT(EPOCH FROM NOW()))
        ON CONFLICT (kid) DO UPDATE SET jwk = EXCLUDED.jwk
    `;
};

const loadPersistedKeys = async (): Promise<JoseKey[]> => {
    const rows = await db`SELECT kid, jwk, created_at FROM oauth_keys ORDER BY kid`;
    const keys: JoseKey[] = [];
    for (const row of rows) {
        try {
            const obj = JSON.parse(row.jwk);
            const key = await JoseKey.fromImportable(obj as any, (obj as any).kid);
            keys.push(key);
        } catch (err) {
            console.error('Could not parse stored JWK', err);
        }
    }
    return keys;
};

const ensureKeys = async (): Promise<JoseKey[]> => {
    let keys = await loadPersistedKeys();
    const needed: string[] = [];
    for (let i = 1; i <= 3; i++) {
        const kid = `key${i}`;
        if (!keys.some(k => k.kid === kid)) needed.push(kid);
    }
    for (const kid of needed) {
        const newKey = await JoseKey.generate(['ES256'], kid);
        await persistKey(newKey);
        keys.push(newKey);
    }
    keys.sort((a, b) => (a.kid ?? '').localeCompare(b.kid ?? ''));
    return keys;
};

// Load keys from database every time (stateless - safe for horizontal scaling)
export const getCurrentKeys = async (): Promise<JoseKey[]> => {
    return await loadPersistedKeys();
};

// Key rotation - rotate keys older than 30 days (monthly rotation)
const KEY_MAX_AGE = 30 * 24 * 60 * 60; // 30 days in seconds

export const rotateKeysIfNeeded = async (): Promise<boolean> => {
    const now = Math.floor(Date.now() / 1000);
    const cutoffTime = now - KEY_MAX_AGE;

    try {
        // Find keys older than 30 days
        const oldKeys = await db`
            SELECT kid, created_at FROM oauth_keys
            WHERE created_at IS NOT NULL AND created_at < ${cutoffTime}
            ORDER BY created_at ASC
        `;

        if (oldKeys.length === 0) {
            console.log('[KeyRotation] No keys need rotation');
            return false;
        }

        console.log(`[KeyRotation] Found ${oldKeys.length} key(s) older than 30 days, rotating oldest key`);

        // Rotate the oldest key
        const oldestKey = oldKeys[0];
        const oldKid = oldestKey.kid;

        // Generate new key with same kid
        const newKey = await JoseKey.generate(['ES256'], oldKid);
        await persistKey(newKey);

        console.log(`[KeyRotation] Rotated key ${oldKid}`);

        return true;
    } catch (err) {
        console.error('[KeyRotation] Failed to rotate keys:', err);
        return false;
    }
};

export const getOAuthClient = async (config: { domain: `http://${string}` | `https://${string}`, clientName: string }) => {
    const keys = await ensureKeys();

    return new NodeOAuthClient({
        clientMetadata: createClientMetadata(config),
        keyset: keys,
        stateStore,
        sessionStore
    });
};

export const getCustomDomainsByDid = async (did: string) => {
    const rows = await db`SELECT * FROM custom_domains WHERE did = ${did} ORDER BY created_at DESC`;
    return rows;
};

export const getCustomDomainInfo = async (domain: string) => {
    const rows = await db`SELECT * FROM custom_domains WHERE domain = ${domain.toLowerCase()}`;
    return rows[0] ?? null;
};

export const getCustomDomainByHash = async (hash: string) => {
    const rows = await db`SELECT * FROM custom_domains WHERE id = ${hash}`;
    return rows[0] ?? null;
};

export const getCustomDomainById = async (id: string) => {
    const rows = await db`SELECT * FROM custom_domains WHERE id = ${id}`;
    return rows[0] ?? null;
};

export const claimCustomDomain = async (did: string, domain: string, hash: string, rkey: string | null = null) => {
    const domainLower = domain.toLowerCase();
    try {
        await db`
            INSERT INTO custom_domains (id, domain, did, rkey, verified, created_at)
            VALUES (${hash}, ${domainLower}, ${did}, ${rkey}, false, EXTRACT(EPOCH FROM NOW()))
        `;
        return { success: true, hash };
    } catch (err) {
        console.error('Failed to claim custom domain', err);
        throw new Error('conflict');
    }
};

export const updateCustomDomainRkey = async (id: string, rkey: string | null) => {
    const rows = await db`
        UPDATE custom_domains
        SET rkey = ${rkey}
        WHERE id = ${id}
        RETURNING *
    `;
    return rows[0] ?? null;
};

export const updateCustomDomainVerification = async (id: string, verified: boolean) => {
    const rows = await db`
        UPDATE custom_domains
        SET verified = ${verified}, last_verified_at = EXTRACT(EPOCH FROM NOW())
        WHERE id = ${id}
        RETURNING *
    `;
    return rows[0] ?? null;
};

export const deleteCustomDomain = async (id: string) => {
    await db`DELETE FROM custom_domains WHERE id = ${id}`;
};

export const getSitesByDid = async (did: string) => {
    const rows = await db`SELECT * FROM sites WHERE did = ${did} ORDER BY created_at DESC`;
    return rows;
};

export const upsertSite = async (did: string, rkey: string, displayName?: string) => {
    try {
        // Only set display_name if provided (not undefined/null/empty)
        const cleanDisplayName = displayName && displayName.trim() ? displayName.trim() : null;

        await db`
            INSERT INTO sites (did, rkey, display_name, created_at, updated_at)
            VALUES (${did}, ${rkey}, ${cleanDisplayName}, EXTRACT(EPOCH FROM NOW()), EXTRACT(EPOCH FROM NOW()))
            ON CONFLICT (did, rkey)
            DO UPDATE SET
                display_name = CASE
                    WHEN EXCLUDED.display_name IS NOT NULL THEN EXCLUDED.display_name
                    ELSE sites.display_name
                END,
                updated_at = EXTRACT(EPOCH FROM NOW())
        `;
        return { success: true };
    } catch (err) {
        console.error('Failed to upsert site', err);
        return { success: false, error: err };
    }
};

export const deleteSite = async (did: string, rkey: string) => {
    try {
        await db`DELETE FROM sites WHERE did = ${did} AND rkey = ${rkey}`;
        return { success: true };
    } catch (err) {
        console.error('Failed to delete site', err);
        return { success: false, error: err };
    }
};