import { MetadataRoute } from 'next'
import type { PrismaClient } from '@prisma/client'
import { getAllToolsComplete } from '@/lib/tools/index'

/**
 * Resolve the canonical site URL at runtime.
 */
function getBaseUrl(): string {
    return (
        process.env.SITE_URL ||
        process.env.NEXT_PUBLIC_APP_URL ||
        'https://open-prompt.netlify.app'
    )
}

// Revalidate sitemap every hour instead of regenerating on every request
export const revalidate = 3600

/**
 * Safely obtain a Prisma client via dynamic import.
 */
async function getPrisma(): Promise<PrismaClient | null> {
    try {
        const { prisma } = await import('@/lib/prisma')
        return prisma
    } catch (error) {
        console.error('Sitemap: failed to initialise Prisma client:', error)
        return null
    }
}

// Tool categories (static list)
const toolCategories = [
    'prompting', 'marketing', 'branding', 'copywriting', 'business',
    'email', 'product', 'hr', 'personal-brand', 'operations',
    'social-media', 'education', 'development', 'creative', 'research',
]

// Main sitemap function
export default async function sitemap(): Promise<MetadataRoute.Sitemap> {
    const BASE_URL = getBaseUrl()

    // 1. Static pages
    const staticPages: MetadataRoute.Sitemap = [
        { url: BASE_URL, lastModified: new Date(), changeFrequency: 'daily', priority: 1 },
        { url: `${BASE_URL}/explore`, lastModified: new Date(), changeFrequency: 'daily', priority: 0.9 },
        { url: `${BASE_URL}/tools`, lastModified: new Date(), changeFrequency: 'weekly', priority: 0.9 },
        { url: `${BASE_URL}/thunderdome`, lastModified: new Date(), changeFrequency: 'daily', priority: 0.8 },
        { url: `${BASE_URL}/workflows`, lastModified: new Date(), changeFrequency: 'weekly', priority: 0.8 },
        { url: `${BASE_URL}/frameworks`, lastModified: new Date(), changeFrequency: 'monthly', priority: 0.7 },
        { url: `${BASE_URL}/leaderboard`, lastModified: new Date(), changeFrequency: 'daily', priority: 0.7 },
        { url: `${BASE_URL}/image-prompts`, lastModified: new Date(), changeFrequency: 'daily', priority: 0.8 },
        { url: `${BASE_URL}/characters`, lastModified: new Date(), changeFrequency: 'weekly', priority: 0.7 },
        { url: `${BASE_URL}/categories`, lastModified: new Date(), changeFrequency: 'weekly', priority: 0.7 },
        { url: `${BASE_URL}/creators`, lastModified: new Date(), changeFrequency: 'daily', priority: 0.7 },
        { url: `${BASE_URL}/collections`, lastModified: new Date(), changeFrequency: 'daily', priority: 0.6 },
        { url: `${BASE_URL}/extension`, lastModified: new Date(), changeFrequency: 'monthly', priority: 0.6 },
        { url: `${BASE_URL}/about`, lastModified: new Date(), changeFrequency: 'monthly', priority: 0.5 },
        { url: `${BASE_URL}/pricing`, lastModified: new Date(), changeFrequency: 'monthly', priority: 0.7 },
        { url: `${BASE_URL}/blog`, lastModified: new Date(), changeFrequency: 'weekly', priority: 0.6 },
        { url: `${BASE_URL}/docs`, lastModified: new Date(), changeFrequency: 'weekly', priority: 0.6 },
        { url: `${BASE_URL}/guides`, lastModified: new Date(), changeFrequency: 'weekly', priority: 0.6 },
        { url: `${BASE_URL}/forum`, lastModified: new Date(), changeFrequency: 'daily', priority: 0.6 },
        { url: `${BASE_URL}/workflow-library`, lastModified: new Date(), changeFrequency: 'weekly', priority: 0.6 },
        { url: `${BASE_URL}/privacy`, lastModified: new Date(), changeFrequency: 'yearly', priority: 0.3 },
        { url: `${BASE_URL}/terms`, lastModified: new Date(), changeFrequency: 'yearly', priority: 0.3 },
    ]

    // 2. Tool category pages
    const toolCategoryPages: MetadataRoute.Sitemap = toolCategories.map((category) => ({
        url: `${BASE_URL}/tools/${category}`,
        lastModified: new Date(),
        changeFrequency: 'weekly' as const,
        priority: 0.7,
    }))

    // 3. Individual tool pages (177+ tools)
    let toolPages: MetadataRoute.Sitemap = []
    try {
        const allTools = getAllToolsComplete()
        toolPages = allTools.map((tool) => ({
            url: `${BASE_URL}/tools/${tool.slug}`,
            lastModified: new Date(),
            changeFrequency: 'monthly' as const,
            priority: 0.65,
        }))
    } catch {
        console.warn('Sitemap: could not load tools list')
    }

    const pages: MetadataRoute.Sitemap = [...staticPages, ...toolCategoryPages, ...toolPages]

    const prisma = await getPrisma()
    if (!prisma) {
        console.warn('Sitemap: returning static-only sitemap (no DB)')
        return pages
    }

    // 4. Dynamic DB pages
    const [promptPages, creatorPages, collectionPages, imagePromptPages, characterPages, workflowPages] =
        await Promise.all([
            fetchPromptPages(prisma, BASE_URL),
            fetchCreatorPages(prisma, BASE_URL),
            fetchCollectionPages(prisma, BASE_URL),
            fetchImagePromptPages(prisma, BASE_URL),
            fetchCharacterPages(prisma, BASE_URL),
            fetchWorkflowPages(prisma, BASE_URL),
        ])

    return [
        ...pages,
        ...promptPages,
        ...creatorPages,
        ...collectionPages,
        ...imagePromptPages,
        ...characterPages,
        ...workflowPages,
    ]
}

// Helpers

async function fetchPromptPages(prisma: PrismaClient, baseUrl: string): Promise<MetadataRoute.Sitemap> {
    try {
        const prompts = await prisma.prompt.findMany({
            where: { visibility: 'public' },
            select: { slug: true, updatedAt: true },
            orderBy: { totalRuns: 'desc' },
            take: 5000,
        })
        return prompts.map((prompt) => ({
            url: `${baseUrl}/p/${prompt.slug}`,
            lastModified: prompt.updatedAt,
            changeFrequency: 'weekly' as const,
            priority: 0.8,
        }))
    } catch (error) {
        console.error('Sitemap: error fetching prompts:', error)
        return []
    }
}

async function fetchCreatorPages(prisma: PrismaClient, baseUrl: string): Promise<MetadataRoute.Sitemap> {
    try {
        const creators = await prisma.user.findMany({
            where: {
                username: { not: null },
                prompts: { some: { visibility: 'public' } },
            },
            select: { username: true, updatedAt: true },
            take: 1000,
        })
        return creators
            .filter((c) => c.username)
            .map((creator) => ({
                url: `${baseUrl}/creator/${creator.username}`,
                lastModified: creator.updatedAt,
                changeFrequency: 'weekly' as const,
                priority: 0.65,
            }))
    } catch (error) {
        console.error('Sitemap: error fetching creators:', error)
        return []
    }
}

async function fetchCollectionPages(prisma: PrismaClient, baseUrl: string): Promise<MetadataRoute.Sitemap> {
    try {
        const collections = await prisma.collection.findMany({
            where: { isPublic: true },
            select: { id: true, updatedAt: true },
            take: 1000,
        })
        return collections.map((collection) => ({
            url: `${baseUrl}/collections/${collection.id}`,
            lastModified: collection.updatedAt,
            changeFrequency: 'weekly' as const,
            priority: 0.5,
        }))
    } catch (error) {
        console.error('Sitemap: error fetching collections:', error)
        return []
    }
}

async function fetchImagePromptPages(prisma: PrismaClient, baseUrl: string): Promise<MetadataRoute.Sitemap> {
    try {
        const imagePrompts = await prisma.imagePrompt.findMany({
            where: { visibility: 'public' },
            select: { slug: true, updatedAt: true },
            orderBy: { totalUses: 'desc' },
            take: 2000,
        })
        return imagePrompts.map((p) => ({
            url: `${baseUrl}/image-prompts/${p.slug}`,
            lastModified: p.updatedAt,
            changeFrequency: 'weekly' as const,
            priority: 0.7,
        }))
    } catch (error) {
        console.error('Sitemap: error fetching image prompts:', error)
        return []
    }
}

async function fetchCharacterPages(prisma: PrismaClient, baseUrl: string): Promise<MetadataRoute.Sitemap> {
    try {
        const characters = await prisma.character.findMany({
            where: { visibility: 'public' },
            select: { slug: true, updatedAt: true },
            orderBy: { totalChats: 'desc' },
            take: 1000,
        })
        return characters.map((c) => ({
            url: `${baseUrl}/characters/${c.slug}`,
            lastModified: c.updatedAt,
            changeFrequency: 'weekly' as const,
            priority: 0.65,
        }))
    } catch (error) {
        console.error('Sitemap: error fetching characters:', error)
        return []
    }
}

async function fetchWorkflowPages(prisma: PrismaClient, baseUrl: string): Promise<MetadataRoute.Sitemap> {
    try {
        const workflows = await prisma.workflow.findMany({
            where: { visibility: 'public' },
            select: { slug: true, updatedAt: true },
            orderBy: { totalRuns: 'desc' },
            take: 500,
        })
        return workflows.map((w) => ({
            url: `${baseUrl}/workflows/${w.slug}`,
            lastModified: w.updatedAt,
            changeFrequency: 'weekly' as const,
            priority: 0.6,
        }))
    } catch (error) {
        console.error('Sitemap: error fetching workflows:', error)
        return []
    }
}