/**
 * Panel.js
 *
 * @author realor
 */

import { I18N } from '../i18n/I18N.js'

class Panel {
    static LARGE_SCREEN_WIDTH = 768
    static POSITIONS = ['left', 'right', 'bottom']
    static HEADER_HEIGHT = 24
    static MARGIN = 6

    constructor(application) {
        this.application = application
        this.panelManager = null
        this.minimumHeight = 100 // greater than HEADER_HEIGHT
        this.preferredHeight = 0 // 0: all available space, > 0: height in pixels

        this.element = document.createElement('div')
        this.element.className = 'panel'
        this.element.style.margin = Panel.MARGIN + 'px'

        this.headerElem = document.createElement('div')
        this.headerElem.className = 'header'
        this.element.appendChild(this.headerElem)

        this.bodyElem = document.createElement('div')
        this.bodyElem.className = 'body'
        this.element.appendChild(this.bodyElem)

        this.minimizeButtonElem = document.createElement('button')
        this.minimizeButtonElem.className = 'minimize'
        I18N.set(this.minimizeButtonElem, 'aria-label', 'button.minimize')
        I18N.set(this.minimizeButtonElem, 'alt', 'button.minimize')
        I18N.set(this.minimizeButtonElem, 'title', 'button.minimize')
        this.headerElem.appendChild(this.minimizeButtonElem)

        this.maximizeButtonElem = document.createElement('button')
        this.maximizeButtonElem.className = 'maximize'
        I18N.set(this.maximizeButtonElem, 'aria-label', 'button.maximize')
        I18N.set(this.maximizeButtonElem, 'alt', 'button.maximize')
        I18N.set(this.maximizeButtonElem, 'title', 'button.maximize')
        this.headerElem.appendChild(this.maximizeButtonElem)

        this.titleElem = document.createElement('a')
        this.titleElem.className = 'title'
        this.titleElem.href = '#'
        this.headerElem.appendChild(this.titleElem)

        this.closeButtonElem = document.createElement('button')
        this.closeButtonElem.className = 'close'
        I18N.set(this.closeButtonElem, 'aria-label', 'button.close')
        I18N.set(this.closeButtonElem, 'alt', 'button.close')
        I18N.set(this.closeButtonElem, 'title', 'button.close')
        this.headerElem.appendChild(this.closeButtonElem)

        this.titleElem.addEventListener(
            'click',
            event => {
                event.preventDefault()
                this.zoom()
            },
            false
        )

        this.minimizeButtonElem.addEventListener('click', event => (this.minimized = true), false)

        this.maximizeButtonElem.addEventListener('click', event => (this.minimized = false), false)

        this.closeButtonElem.addEventListener('click', event => (this.visible = false), false)

        this._position = null
        this.position = 'left'
        this.opacity = application.panelOpacity
    }

    get title() {
        return this.titleElem.innerHTML
    }

    set title(title) {
        this.titleElem.innerHTML = title
        I18N.set(this.titleElem, 'innerHTML', title)
    }

    get position() {
        return this._position
    }

    set position(position) {
        if (position !== this._position) {
            var element = this.element
            if (this._position) {
                element.classList.remove(this._position)
            }
            this._position = position
            element.classList.add(position)
            if (this.panelManager) this.panelManager.updateLayout()
        }
    }

    get visible() {
        return this.element.classList.contains('show')
    }

    set visible(visible) {
        if (this.panelManager) this.panelManager.setAnimationEnabled(false)

        let prevVisible = this.visible
        if (visible && !prevVisible) {
            this.element.classList.add('show')
            if (this.panelManager) {
                this.element.classList.remove('minimized')
                this.panelManager.preferredPanel = this
                this.panelManager.updateLayout()
            }
            this.onShow()
        } else if (!visible && prevVisible) {
            this.element.classList.remove('show')
            if (this.panelManager) this.panelManager.updateLayout()
            this.onHide()
        }
    }

    get minimized() {
        return this.element.classList.contains('minimized')
    }

    set minimized(minimized) {
        if (this.panelManager) {
            this.panelManager.setAnimationEnabled(true)
            if (minimized === false) {
                this.panelManager.preferredPanel = this
            }
        }

        let prevMinimized = this.minimized
        if (minimized && !prevMinimized) {
            this.element.classList.add('minimized')
            if (this.panelManager) this.panelManager.updateLayout()
            this.onMinimize()
        } else if (!minimized && prevMinimized) {
            this.element.classList.remove('minimized')
            if (this.panelManager) this.panelManager.updateLayout()
            this.onMaximize()
        }
    }

    setTitle(title) {
        this.title = title
        return this
    }

    setPosition(position) {
        this.position = position
        return this
    }

    setClassName(className) {
        this.element.classList.add(className)
        return this
    }

    zoom() {
        if (this.panelManager) {
            let position = this.panelManager.isLargeScreen() ? this.position : null
            let panels = this.panelManager.getPanels(position, true)
            for (let panel of panels) {
                if (panel !== this) {
                    panel.element.classList.add('minimized')
                }
            }
            this.element.classList.remove('minimized')
            this.panelManager.setAnimationEnabled(true)
            this.panelManager.updateLayout()
        }
    }

    get opacity() {
        return this._opacity
    }

    set opacity(opacity) {
        this._opacity = opacity
        this.element.style.background = 'rgba(255,255,255,' + opacity + ')'

        let headerOpacity = Math.min(opacity + 0.2, 1)
        this.headerElem.style.background = 'rgba(255,255,255,' + headerOpacity + ')'
    }

    onShow() {}

    onHide() {}

    onMinimize() {}

    onMaximize() {}
}

class PanelManager {
    constructor(container) {
        this.container = container || document.body
        this.margin = 0
        this.headerHeight = Panel.HEADER_HEIGHT
        this.panels = []
        this.preferredPanel = null

        this.resizers = {}
        this.resizers.left = new PanelResizer(this, 'left')
        this.resizers.right = new PanelResizer(this, 'right')

        window.addEventListener(
            'resize',
            event => {
                this.setAnimationEnabled(false)
                this.updateLayout()
            },
            false
        )
    }

    addPanel(panel) {
        let index = this.panels.indexOf(panel)
        if (index === -1) {
            panel.panelManager = this
            this.panels.push(panel)
            this.container.appendChild(panel.element)
        }
    }

    removePanel(panel) {
        let index = this.panels.indexOf(panel)
        if (index !== -1) {
            panel.panelManager = null
            this.panels.splice(index, 1)
            this.container.removeChild(panel.element)
        }
    }

    getPanels(position = null, visible = null) {
        let selection = []
        for (let i = 0; i < this.panels.length; i++) {
            let panel = this.panels[i]
            if (position === null || panel.position === position) {
                if (visible === null || panel.visible === visible) {
                    selection.push(panel)
                }
            }
        }
        return selection
    }

    isAnimationEnabled() {
        return this.container.classList.contains('animate')
    }

    setAnimationEnabled(enabled) {
        if (enabled) {
            this.container.classList.add('animate')
        } else {
            this.container.classList.remove('animate')
        }
    }

    updateLayout() {
        const container = this.container
        const height = container.clientHeight - Panel.MARGIN - 1
        if (this.isLargeScreen()) {
            this.resizers.left.enabled = true
            this.resizers.right.enabled = true

            let positions = Panel.POSITIONS
            for (var i = 0; i < positions.length; i++) {
                let position = positions[i]
                let panels = this.getPanels(position, true)
                let maxHeight = this.layoutElements(panels, height)
                let resizer = this.resizers[position]
                if (resizer) {
                    resizer.height = maxHeight
                    resizer.updateBar()
                    resizer.saveWidth()
                }
            }
        } else {
            this.resizers.left.enabled = false
            this.resizers.right.enabled = false

            let panels = this.getPanels(null, true)
            this.layoutElements(panels, Math.floor(height / 2))
        }
    }

    layoutElements(panels, height) {
        let minimumHeight = 0

        // calculate minimumHeight
        for (let panel of panels) {
            if (panel.minimized) {
                minimumHeight += this.headerHeight
            } else {
                minimumHeight += panel.minimumHeight
            }
            minimumHeight += Panel.MARGIN
        }

        // minimize required panels to fit all
        let total = panels.length
        let remainingHeight = height - minimumHeight
        let i = 0
        while (remainingHeight < 0 && i < total) {
            let j = total - i - 1
            let panel = panels[j]
            if (!panel.minimized && panel !== this.preferredPanel) {
                panel.element.classList.add('minimized')
                remainingHeight += panel.minimumHeight - this.headerHeight
            }
            i++
        }

        // calculate largePanelExtraHeight
        let largePanelCount = 0
        let smallPanelRequiredHeight = 0

        for (let panel of panels) {
            if (!panel.minimized) {
                if (panel.preferredHeight === 0) {
                    largePanelCount++
                } else if (panel.preferredHeight > panel.minimumHeight) {
                    smallPanelRequiredHeight += panel.preferredHeight - panel.minimumHeight
                }
            }
        }

        let largePanelExtraHeight = 0
        let largePanelRemainingHeight = remainingHeight - smallPanelRequiredHeight
        if (largePanelRemainingHeight > 0 && largePanelCount > 0) {
            largePanelExtraHeight = Math.floor(largePanelRemainingHeight / largePanelCount)
        }

        // layout panels
        let bottom = this.margin
        for (let i = 0; i < total; i++) {
            let j = total - i - 1
            let panel = panels[j]

            // set panel bottom
            panel.element.style.bottom = bottom + 'px'

            // set panel width
            if (this.isLargeScreen()) {
                let resizer = this.resizers[panel.position]
                if (resizer) {
                    panel.element.style.width = resizer.width - Panel.MARGIN + 'px'
                }
            } else {
                panel.element.style.width = ''
            }

            // set panel height
            let currentPanelHeight
            if (panel.minimized) {
                currentPanelHeight = this.headerHeight
            } else if (panel.preferredHeight === 0) {
                // large panel
                currentPanelHeight = panel.minimumHeight + largePanelExtraHeight
                remainingHeight -= largePanelExtraHeight
            } // small panel
            else {
                currentPanelHeight = panel.minimumHeight

                let requiredHeight = panel.preferredHeight - panel.minimumHeight
                if (requiredHeight > 0) {
                    let extraHeight = Math.min(remainingHeight, requiredHeight)

                    currentPanelHeight += extraHeight
                    remainingHeight -= extraHeight
                }
            }
            panel.element.style.height = currentPanelHeight + 'px'

            bottom += currentPanelHeight + Panel.MARGIN
        }
        return bottom
    }

    isLargeScreen() {
        return this.container.clientWidth > Panel.LARGE_SCREEN_WIDTH
    }
}

class PanelResizer {
    constructor(panelManager, side) {
        this.panelManager = panelManager
        this.side = side
        this.height = 0
        this.width = 0

        this.element = document.createElement('div')
        const element = this.element
        const container = panelManager.container

        element.className = 'resizer'
        container.appendChild(element)

        this.restoreWidth()
        this.updateBar()

        const move = event => {
            this.width = this.getCurrentWidth(event)
            this.updateBar()
            this.panelManager.updateLayout()
        }

        const reset = event => {
            element.removeEventListener('pointermove', move, false)
            element.removeEventListener('pointerup', reset, false)
            element.releasePointerCapture(event.pointerId)
        }

        element.addEventListener('pointerdown', event => {
            element.addEventListener('pointermove', move, false)
            element.addEventListener('pointerup', reset, false)
            element.setPointerCapture(event.pointerId)
        })
    }

    updateBar() {
        this.element.style.height = this.height + 'px'
        this.element.style[this.side] = this.width + 'px'
    }

    get enabled() {
        return this.element.style.display === ''
    }

    set enabled(enabled) {
        this.element.style.display = enabled ? '' : 'none'
    }

    restoreWidth() {
        let value = window.localStorage.getItem('bimrocket.resizer.' + this.side)
        this.width = parseInt(value) || 250
    }

    saveWidth() {
        window.localStorage.setItem('bimrocket.resizer.' + this.side, this.width)
    }

    getCurrentWidth(event) {
        const rect = this.panelManager.container.getBoundingClientRect()
        let curWidth = 0
        if (this.side === 'left') {
            curWidth = event.clientX - rect.left
        } else if (this.side === 'right') {
            curWidth = rect.left + rect.width - event.clientX
        }
        return curWidth
    }
}

export { Panel, PanelManager }