import { downloadUpscale } from "/upscale/image.js"

const $ = (selector, root = document) => root.querySelector(selector)
const $$ = (selector, root = document) => [...root.querySelectorAll(selector)]
const p = new URLSearchParams(location.search).get("p")
const api = (path, query = {}) => `${path}?${new URLSearchParams({ p, ...query })}`
const preview = image => api("/api/images/preview", { path: image.path, v: image.version })
const original = image => api("/api/images/original", { path: image.path, v: image.version })
const MIN_ZOOM = 1
const MAX_ZOOM = 8
const ZOOM_STEP = 1.2
const INFINITE = "*"
const FAVORITES = "favorites"
const SEARCH_DELAY = 250
const LOAD_MARGIN = "640px"
const PREVIEW_MARGIN = "320px"

class ImageExplorer extends HTMLElement {
    connectedCallback() {
        this.innerHTML = `
            <main>
                <div class="date-heading">
                    <button class="date-prev" type="button" aria-label="Previous date" hidden>←</button>
                    <h1>Image folders</h1>
                    <button class="date-next" type="button" aria-label="Next date" hidden>→</button>
                </div>
                <div class="tools">
                    <button class="back" type="button" hidden>Folders</button>
                    <input type="search" placeholder="Filter folders" aria-label="Filter folders">
                    <button class="favorites" type="button" aria-pressed="false" hidden>Favorites</button>
                    <button class="all" type="button">Select all</button>
                    <button class="clear" type="button">Clear</button>
                    <button class="download primary" type="button">Download 7z</button>
                    <button class="delete" type="button">Delete</button>
                </div>
                <div class="status">Loading</div>
                <div class="content"></div>
            </main>
            <dialog class="lightbox">
                <div class="image-actions">
                    <button class="upscale primary" type="button">Upscale</button>
                    <button class="star expanded-star" type="button" aria-label="Star image"></button>
                    <span class="upscale-status" role="status" aria-live="polite"></span>
                </div>
                <button class="close" type="button" aria-label="Close">Close</button>
                <div class="zoom-tools">
                    <button class="zoom-out" type="button" aria-label="Zoom out">−</button>
                    <button class="reset" type="button">Reset</button>
                    <button class="zoom-in" type="button" aria-label="Zoom in">+</button>
                </div>
                <pre class="prompt"></pre>
                <div class="viewer"><img alt="" draggable="false"></div>
            </dialog>`
        this.cache = new Map()
        this.setupPreviews()
        this.pageObserver = new IntersectionObserver(entries => {
            if (entries.some(entry => entry.isIntersecting)) this.loadMore()
        }, { rootMargin: LOAD_MARGIN })
        this.load()
        $(".back", this).addEventListener("click", () => this.load())
        $(".date-prev", this).addEventListener("click", () => this.navigateDate(1))
        $(".date-next", this).addEventListener("click", () => this.navigateDate(-1))
        $(".all", this).addEventListener("click", () => this.select(true))
        $(".clear", this).addEventListener("click", () => this.select(false))
        $(".favorites", this).addEventListener("click", () => this.toggleFavorites())
        $(".download", this).addEventListener("click", () => this.download())
        $(".delete", this).addEventListener("click", () => this.delete())
        $("input[type=search]", this).addEventListener("input", event => {
            this.filter(event.target.value)
        })
        this.setupLightbox()
    }

    async load(folder, favoritesOnly = false, query = "") {
        clearTimeout(this.searchTimer)
        this.controller?.abort()
        const controller = new AbortController()
        this.controller = controller
        this.folder = folder
        $(".lightbox", this).close()
        this.favoritesOnly = folder === FAVORITES || favoritesOnly
        this.searchQuery = query
        this.images = []
        this.imagePaths = new Set()
        this.groupGrids = new Map()
        this.nextOffset = folder ? 0 : null
        this.loadingPage = false
        this.more = null
        $(".status", this).textContent = "Loading"
        this.previewObserver.disconnect()
        this.pageObserver.disconnect()
        $(".content", this).replaceChildren()
        $("h1", this).textContent = folder === FAVORITES ? "Favorites"
            : folder === INFINITE ? "Infinite" : folder || "Image folders"
        $(".back", this).hidden = !folder
        $(".all", this).textContent = folder ? "Select loaded" : "Select all"
        const favorites = $(".favorites", this)
        favorites.hidden = !folder || folder === FAVORITES
        favorites.setAttribute("aria-pressed", this.favoritesOnly)
        this.updateDateNav()
        const search = $("input[type=search]", this)
        search.value = query
        search.placeholder = folder ? "Search positive prompts" : "Filter folders"
        search.setAttribute("aria-label", search.placeholder)
        if (folder) {
            if (folder !== INFINITE && folder !== FAVORITES) this.addImages([])
            this.more = document.createElement("button")
            this.more.className = "load-more"
            this.more.type = "button"
            this.more.textContent = "Load more"
            this.more.addEventListener("click", () => this.loadMore())
            $(".content", this).append(this.more)
            this.pageObserver.observe(this.more)
            await this.loadMore()
            return
        }
        try {
            let data = this.cache.get(folder)
            if (!data) {
                const response = await fetch(api("/api/images"), { signal: controller.signal })
                if (!response.ok) throw new Error("Unable to load folders")
                data = await response.json()
            }
            if (controller !== this.controller) return
            this.cache.set(folder, data)
            this.folders = [FAVORITES, INFINITE, ...data.folders.map(item => item.name)]
            this.addFolders(data.folders)
            this.update()
        } catch (error) {
            if (controller === this.controller) $(".status", this).textContent = error.message
        }
    }

    loadMore() {
        if (this.loadingPage) return this.pageTask
        if (this.nextOffset === null || !this.folder || this.pendingStars?.size) return
        this.pageTask = this.loadPage()
        return this.pageTask
    }

    async loadPage() {
        const controller = this.controller
        const grouped = this.folder === INFINITE || this.folder === FAVORITES
        const query = {
            offset: this.nextOffset,
            favorites: this.favoritesOnly,
            search: this.searchQuery,
            ...(grouped ? { infinite: true } : { folder: this.folder }),
        }
        this.loadingPage = true
        this.more.disabled = true
        this.more.textContent = "Loading"
        try {
            const response = await fetch(api("/api/images", query), { signal: controller.signal })
            if (!response.ok) throw new Error("Unable to load images")
            const data = await response.json()
            if (controller !== this.controller) return
            if (grouped) this.addGroups(data.groups)
            else this.addImages(data.images)
            this.nextOffset = data.next_offset
            this.more.hidden = this.nextOffset === null
            this.more.textContent = "Load more"
            this.update()
            this.pageObserver.unobserve(this.more)
            if (this.nextOffset !== null) this.pageObserver.observe(this.more)
        } catch (error) {
            if (controller !== this.controller) return
            this.pageObserver.unobserve(this.more)
            this.more.textContent = "Retry loading images"
            $(".status", this).textContent = error.message
        } finally {
            if (controller === this.controller) {
                this.loadingPage = false
                this.more.disabled = false
            }
        }
    }

    updateDateNav() {
        const index = this.folders?.indexOf(this.folder) ?? -1
        const previous = $(".date-prev", this)
        const next = $(".date-next", this)
        previous.hidden = index < 0
        next.hidden = index < 0
        if (index < 0) return
        previous.disabled = index === this.folders.length - 1
        next.disabled = index === 0
        previous.title = this.folders[index + 1] || ""
        next.title = this.folders[index - 1] || ""
    }

    navigateDate(step) {
        const index = this.folders.indexOf(this.folder) + step
        if (this.folders[index]) this.load(this.folders[index])
    }

    setupPreviews() {
        this.previewObserver = new IntersectionObserver(entries => {
            for (const entry of entries) {
                if (!entry.isIntersecting) continue
                const image = entry.target
                image.src = image.dataset.src
                delete image.dataset.src
                this.previewObserver.unobserve(image)
            }
        }, { rootMargin: PREVIEW_MARGIN })
    }

    addFolders(folders) {
        const grid = document.createElement("div")
        grid.className = "grid folders"
        for (const [folder, label] of [[FAVORITES, "Favorites"], [INFINITE, "Infinite"]]) {
            const card = document.createElement("div")
            card.className = "folder entry"
            card.dataset.name = label.toLowerCase()
            const open = document.createElement("button")
            open.className = "folder-open"
            open.type = "button"
            open.addEventListener("click", () => this.load(folder))
            const name = document.createElement("strong")
            name.textContent = label
            open.append(name)
            card.append(open)
            grid.append(card)
        }
        for (const folder of folders) {
            const card = document.createElement("div")
            card.className = "folder entry"
            card.dataset.name = folder.name.toLowerCase()
            const input = this.checkbox(folder.name)
            const open = document.createElement("button")
            open.className = "folder-open"
            open.type = "button"
            open.addEventListener("click", () => this.load(folder.name))
            const name = document.createElement("strong")
            name.textContent = folder.name
            open.append(name)
            card.append(input, open)
            grid.append(card)
        }
        $(".content", this).append(grid)
    }

    appendImages(grid, images) {
        const cards = document.createDocumentFragment()
        for (const image of images) {
            if (this.imagePaths.has(image.path)) continue
            this.imagePaths.add(image.path)
            this.images.push(image)
            cards.append(this.card(image))
        }
        grid.append(cards)
    }

    addImages(images) {
        let grid = $(".content > .grid", this)
        if (!grid) {
            grid = document.createElement("div")
            grid.className = "grid"
            $(".content", this).append(grid)
        }
        this.appendImages(grid, images)
    }

    addGroups(groups) {
        const content = $(".content", this)
        for (const group of groups) {
            let grid = this.groupGrids.get(group.name)
            if (!grid) {
                const section = document.createElement("section")
                section.className = "date-group"
                const heading = document.createElement("h2")
                heading.textContent = group.name
                grid = document.createElement("div")
                grid.className = "grid"
                section.append(heading, grid)
                content.insertBefore(section, this.more)
                this.groupGrids.set(group.name, grid)
            }
            this.appendImages(grid, group.images)
            grid.parentElement.hidden = !$(".entry:not([hidden])", grid)
        }
    }

    checkbox(path) {
        const input = document.createElement("input")
        input.type = "checkbox"
        input.className = "item"
        input.dataset.path = path
        input.setAttribute("aria-label", `Select ${path}`)
        input.addEventListener("change", () => this.update())
        return input
    }

    card(image) {
        const card = document.createElement("div")
        card.className = "image entry"
        card.classList.toggle("favorite", image.starred)
        card.dataset.name = image.name.toLowerCase()
        card.dataset.prompt = image.prompt.toLowerCase()
        card.dataset.path = image.path
        const open = document.createElement("button")
        open.className = "preview"
        open.type = "button"
        open.addEventListener("click", () => this.openImage(image))
        const picture = document.createElement("img")
        picture.alt = image.name
        picture.decoding = "async"
        picture.dataset.src = preview(image)
        this.previewObserver.observe(picture)
        open.append(picture)
        const star = this.starButton(image, "card-star")
        const info = document.createElement("label")
        info.className = "image-info"
        const input = this.checkbox(image.path)
        const name = document.createElement("strong")
        name.className = "name"
        name.textContent = image.name
        info.append(input, name)
        card.append(open, star, info)
        return card
    }

    starButton(image, className) {
        const button = document.createElement("button")
        button.className = `star ${className}`
        button.type = "button"
        button.dataset.path = image.path
        button.addEventListener("click", () => this.toggleStar(image))
        this.renderStar(button, image.starred)
        return button
    }

    renderStar(button, starred) {
        button.textContent = starred ? "★" : "☆"
        button.setAttribute("aria-pressed", starred)
        button.setAttribute("aria-label", `${starred ? "Unstar" : "Star"} image`)
    }

    setStar(path, starred) {
        for (const image of this.images) {
            if (image.path === path) image.starred = starred
        }
        for (const button of $$(".star", this)) {
            if (button.dataset.path === path) this.renderStar(button, starred)
        }
        for (const card of $$(".image", this)) {
            if (card.dataset.path !== path) continue
            card.classList.toggle("favorite", starred)
            card.hidden = this.favoritesOnly && !starred
            if (card.hidden) $(".item", card).checked = false
        }
        for (const group of $$(".date-group", this)) {
            group.hidden = !$(".entry:not([hidden])", group)
        }
        this.update()
    }

    async toggleStar(image) {
        this.pendingStars ||= new Set()
        if (this.pendingStars.has(image.path)) return
        this.pendingStars.add(image.path)
        const controller = this.controller
        const buttons = $$(".star", this).filter(button => (
            button.dataset.path === image.path
        ))
        for (const button of buttons) button.disabled = true
        const starred = !image.starred
        try {
            await this.pageTask
            if (controller !== this.controller) return
            this.setStar(image.path, starred)
            const response = await fetch(api("/api/images/star"), {
                method: "POST",
                headers: { "Content-Type": "application/json" },
                body: JSON.stringify({ path: image.path, starred }),
            })
            if (!response.ok) throw new Error("Unable to update star")
            if (controller === this.controller && this.favoritesOnly && !starred
                && this.nextOffset !== null) {
                this.nextOffset = Math.max(0, this.nextOffset - 1)
            }
        } catch (error) {
            this.setStar(image.path, !starred)
            $(".status", this).textContent = error.message
        } finally {
            this.pendingStars.delete(image.path)
            for (const button of buttons) button.disabled = false
            if (this.more && this.nextOffset !== null) {
                this.pageObserver.unobserve(this.more)
                this.pageObserver.observe(this.more)
            }
        }
    }

    select(checked) {
        for (const input of $$(".entry:not([hidden]) .item", this)) input.checked = checked
        this.update()
    }

    update() {
        const count = $$(".item:checked", this).length
        $(".status", this).textContent = `${count} selected`
    }

    toggleFavorites() {
        this.load(this.folder, !this.favoritesOnly, $("input[type=search]", this).value)
    }

    filter(value) {
        clearTimeout(this.searchTimer)
        if (this.folder) {
            this.searchTimer = setTimeout(() => {
                this.load(this.folder, this.favoritesOnly, value)
            }, SEARCH_DELAY)
            return
        }
        const query = value.trim().toLowerCase()
        for (const entry of $$(".entry", this)) {
            entry.hidden = !entry.dataset.name.includes(query)
        }
    }

    async download() {
        const items = $$(".item:checked", this).map(input => input.dataset.path)
        if (!items.length) return
        const button = $(".download", this)
        button.disabled = true
        $(".status", this).textContent = "Building archive"
        try {
            const response = await fetch(api("/api/images/download"), {
                method: "POST",
                headers: { "Content-Type": "application/json" },
                body: JSON.stringify({ items }),
            })
            if (!response.ok) throw new Error("Archive failed")
            const url = URL.createObjectURL(await response.blob())
            const link = document.createElement("a")
            link.href = url
            link.download = "images.7z"
            link.click()
            URL.revokeObjectURL(url)
        } catch (error) {
            $(".status", this).textContent = error.message
            return
        } finally {
            button.disabled = false
        }
        this.update()
    }

    async delete() {
        const items = $$(".item:checked", this).map(input => input.dataset.path)
        if (!items.length || !confirm(`Delete ${items.length} selected item(s)?`)) return
        const button = $(".delete", this)
        button.disabled = true
        $(".status", this).textContent = "Deleting"
        try {
            const response = await fetch(api("/api/images/delete"), {
                method: "POST",
                headers: { "Content-Type": "application/json" },
                body: JSON.stringify({ items }),
            })
            if (!response.ok) throw new Error("Delete failed")
            this.cache.clear()
            await this.load(this.folder, this.favoritesOnly, $("input[type=search]", this).value)
        } catch (error) {
            $(".status", this).textContent = error.message
        } finally {
            button.disabled = false
        }
    }

    async upscale() {
        const image = this.images[this.imageIndex]
        const button = $(".upscale", this)
        const status = $(".upscale-status", this)
        button.disabled = true
        status.textContent = "Upscaling…"
        try {
            await downloadUpscale({ path: image.path, name: image.name })
            status.textContent = "Downloaded"
        } catch (error) {
            status.textContent = error.message
        } finally {
            button.disabled = false
        }
    }

    setupLightbox() {
        const dialog = $(".lightbox", this)
        const viewer = $(".viewer", dialog)
        const image = $("img", viewer)
        $(".close", dialog).addEventListener("click", () => dialog.close())
        $(".upscale", dialog).addEventListener("click", () => this.upscale())
        $(".expanded-star", dialog).addEventListener("click", () => {
            this.toggleStar(this.images[this.imageIndex])
        })
        $(".zoom-out", dialog).addEventListener("click", () => this.zoom(1 / ZOOM_STEP))
        $(".reset", dialog).addEventListener("click", () => this.resetView())
        $(".zoom-in", dialog).addEventListener("click", () => this.zoom(ZOOM_STEP))
        dialog.addEventListener("click", event => {
            if (event.target === dialog) dialog.close()
        })
        dialog.addEventListener("keydown", event => {
            if (event.key === "ArrowLeft") this.moveImage(-1)
            else if (event.key === "ArrowRight") this.moveImage(1)
            else if (event.key === "+" || event.key === "=") this.zoom(ZOOM_STEP)
            else if (event.key === "-") this.zoom(1 / ZOOM_STEP)
            else if (event.key === "0") this.resetView()
            else return
            event.preventDefault()
        })
        dialog.addEventListener("close", () => image.removeAttribute("src"))
        image.addEventListener("load", () => this.resetView())
        viewer.addEventListener("wheel", event => this.zoomWheel(event), {
            passive: false,
        })
        viewer.addEventListener("pointerdown", event => this.startPan(event))
        viewer.addEventListener("pointermove", event => this.pan(event))
        viewer.addEventListener("pointerup", event => this.stopPan(event))
        viewer.addEventListener("pointercancel", event => this.stopPan(event))
        viewer.addEventListener("dblclick", () => this.resetView())
    }

    openImage(image) {
        this.imageIndex = this.images.indexOf(image)
        this.showImage(image)
        $(".lightbox", this).showModal()
    }

    showImage(image) {
        const dialog = $(".lightbox", this)
        $("img", dialog).src = original(image)
        $("img", dialog).alt = image.name
        $(".prompt", dialog).textContent = this.formatPrompt(image)
        $(".upscale-status", dialog).textContent = ""
        const star = $(".expanded-star", dialog)
        star.dataset.path = image.path
        this.renderStar(star, image.starred)
    }

    async moveImage(step) {
        const controller = this.controller
        const current = this.images[this.imageIndex]
        if (step > 0 && this.imageIndex === this.images.length - 1
            && this.nextOffset !== null) await this.loadMore()
        if (controller !== this.controller) return
        const images = this.images.filter(image => !this.favoritesOnly || image.starred)
        if (!images.length) {
            $(".lightbox", this).close()
            return
        }
        const index = images.indexOf(current)
        const image = images[(index + step + images.length) % images.length]
        this.imageIndex = this.images.indexOf(image)
        this.showImage(image)
    }

    formatPrompt(image) {
        if (!image.prompt) return "Prompt unavailable"
        const lines = [`1:${image.prompt}`]
        if (image.second_prompt) {
            lines.push(`2:${image.second_prompt}`)
        }
        return lines.join("\n")
    }

    resetView() {
        const viewer = $(".viewer", this)
        const image = $("img", viewer)
        this.baseZoom = Math.min(
            viewer.clientWidth / image.naturalWidth,
            viewer.clientHeight / image.naturalHeight,
            MIN_ZOOM,
        )
        this.zoomLevel = this.baseZoom
        this.panX = 0
        this.panY = 0
        this.renderView()
    }

    zoomWheel(event) {
        event.preventDefault()
        const viewer = $(".viewer", this)
        const box = viewer.getBoundingClientRect()
        const x = event.clientX - box.left - box.width / 2
        const y = event.clientY - box.top - box.height / 2
        this.zoom(event.deltaY < 0 ? ZOOM_STEP : 1 / ZOOM_STEP, x, y)
    }

    zoom(step, x = 0, y = 0) {
        const level = Math.min(
            Math.max(this.zoomLevel * step, this.baseZoom),
            MAX_ZOOM,
        )
        const ratio = level / this.zoomLevel
        this.panX = x - (x - this.panX) * ratio
        this.panY = y - (y - this.panY) * ratio
        this.zoomLevel = level
        this.renderView()
    }

    startPan(event) {
        event.currentTarget.setPointerCapture(event.pointerId)
        this.dragX = event.clientX
        this.dragY = event.clientY
    }

    pan(event) {
        if (!event.currentTarget.hasPointerCapture(event.pointerId)) return
        this.panX += event.clientX - this.dragX
        this.panY += event.clientY - this.dragY
        this.dragX = event.clientX
        this.dragY = event.clientY
        this.renderView()
    }

    stopPan(event) {
        if (event.currentTarget.hasPointerCapture(event.pointerId)) {
            event.currentTarget.releasePointerCapture(event.pointerId)
        }
    }

    renderView() {
        $("img", $(".viewer", this)).style.transform = `
            translate(-50%, -50%)
            translate(${this.panX}px, ${this.panY}px)
            scale(${this.zoomLevel})
        `
    }
}

customElements.define("image-explorer", ImageExplorer)