package chromedp

import (
	"time"

	"github.com/knq/chromedp/cdp"
)

const (
	// DefaultNewTargetTimeout is the default time to wait for a new target to
	// be started.
	DefaultNewTargetTimeout = 3 * time.Second

	// DefaultCheckDuration is the default time to sleep between a check.
	DefaultCheckDuration = 50 * time.Millisecond

	// DefaultPoolStartPort is the default start port number.
	DefaultPoolStartPort = 9000

	// DefaultPoolEndPort is the default end port number.
	DefaultPoolEndPort = 10000

	// textJS is a javascript snippet that returns the concatenated textContent
	// of all visible (ie, offsetParent !== null) children.
	textJS = `(function(a) {
		var s = '';
		for (var i = 0; i < a.length; i++) {
			if (a[i].offsetParent !== null) {
				s += a[i].textContent;
			}
		}
		return s;
	})($x("%s/node()"))`

	// blurJS is a javscript snippet that blurs the specified element.
	blurJS = `(function(a) {
		a[0].blur();
		return true;
	})($x('%s'))`

	// scrollJS is a javascript snippet that scrolls the window to the
	// specified x, y coordinates and then returns the actual window x/y after
	// execution.
	scrollJS = `(function(x, y) {
		window.scrollTo(x, y);
		return [window.scrollX, window.scrollY];
	})(%d, %d)`

	// submitJS is a javascript snippet that will call the containing form's
	// submit function, returning true or false if the call was successful.
	submitJS = `(function(a) {
		if (a[0].nodeName === 'FORM') {
			a[0].submit();
			return true;
		} else if (a[0].form !== null) {
			a[0].form.submit();
			return true;
		}
		return false;
	})($x('%s'))`

	// resetJS is a javascript snippet that will call the containing form's
	// reset function, returning true or false if the call was successful.
	resetJS = `(function(a) {
		if (a[0].nodeName === 'FORM') {
			a[0].reset();
			return true;
		} else if (a[0].form !== null) {
			a[0].form.reset();
			return true;
		}
		return false;
	})($x('%s'))`

	// valueJS is a javascript snippet that returns the value of a specified
	// node.
	valueJS = `(function(a) {
		return a[0].value;
	})($x('%s'))`

	// setValueJS is a javascript snippet that sets the value of the specified
	// node, and returns the value.
	setValueJS = `(function(a, val) {
		return a[0].value = val;
	})($x('%s'), '%s')`

	// visibleJS is a javascript snippet that returns true or false depending
	// on if the specified node's offsetParent is not null.
	visibleJS = `(function(a) {
		return a[0].offsetParent !== null
	})($x('%s'))`
)

// frameOp is a frame manipulation operation.
type frameOp func(*cdp.Frame)

/*func domContentEventFired(f *cdp.Frame) {
}

func loadEventFired(f *cdp.Frame) {
}*/

func frameAttached(id cdp.FrameID) frameOp {
	return func(f *cdp.Frame) {
		f.ParentID = id
		setFrameState(f, cdp.FrameAttached)
	}
}

/*func frameNavigated(f *cdp.Frame) {
	setFrameState(f, cdp.FrameNavigated)
}*/

func frameDetached(f *cdp.Frame) {
	f.ParentID = cdp.EmptyFrameID
	clearFrameState(f, cdp.FrameAttached)
}

func frameStartedLoading(f *cdp.Frame) {
	setFrameState(f, cdp.FrameLoading)
}

func frameStoppedLoading(f *cdp.Frame) {
	clearFrameState(f, cdp.FrameLoading)
}

func frameScheduledNavigation(f *cdp.Frame) {
	setFrameState(f, cdp.FrameScheduledNavigation)
}

func frameClearedScheduledNavigation(f *cdp.Frame) {
	clearFrameState(f, cdp.FrameScheduledNavigation)
}

/*func frameResized(f *cdp.Frame) {
	// TODO
}*/

// setFrameState sets the frame state via bitwise or (|).
func setFrameState(f *cdp.Frame, fs cdp.FrameState) {
	f.State |= fs
}

// clearFrameState clears the frame state via bit clear (&^).
func clearFrameState(f *cdp.Frame, fs cdp.FrameState) {
	f.State &^= fs
}

// nodeOp is a node manipulation operation.
type nodeOp func(*cdp.Node)

func walk(m map[cdp.NodeID]*cdp.Node, n *cdp.Node) {
	n.RLock()
	defer n.RUnlock()
	m[n.NodeID] = n

	for _, c := range n.Children {
		c.Lock()
		c.Parent = n
		c.Invalidated = n.Invalidated
		c.Unlock()

		walk(m, c)
	}

	for _, c := range n.ShadowRoots {
		c.Lock()
		c.Parent = n
		c.Invalidated = n.Invalidated
		c.Unlock()

		walk(m, c)
	}

	for _, c := range n.PseudoElements {
		c.Lock()
		c.Parent = n
		c.Invalidated = n.Invalidated
		c.Unlock()

		walk(m, c)
	}

	for _, c := range []*cdp.Node{n.ContentDocument, n.TemplateContent, n.ImportedDocument} {
		if c == nil {
			continue
		}

		c.Lock()
		c.Parent = n
		c.Invalidated = n.Invalidated
		c.Unlock()

		walk(m, c)
	}
}

func setChildNodes(m map[cdp.NodeID]*cdp.Node, nodes []*cdp.Node) nodeOp {
	return func(n *cdp.Node) {
		n.Lock()
		n.Children = nodes
		n.Unlock()

		walk(m, n)
	}
}

func attributeModified(name, value string) nodeOp {
	return func(n *cdp.Node) {
		n.Lock()
		defer n.Unlock()

		var found bool
		var i int
		for ; i < len(n.Attributes); i += 2 {
			if n.Attributes[i] == name {
				found = true
				break
			}
		}

		if found {
			n.Attributes[i] = name
			n.Attributes[i+1] = value
		} else {
			n.Attributes = append(n.Attributes, name, value)
		}
	}
}

func attributeRemoved(name string) nodeOp {
	return func(n *cdp.Node) {
		n.Lock()
		defer n.Unlock()

		var a []string
		for i := 0; i < len(n.Attributes); i += 2 {
			if n.Attributes[i] == name {
				continue
			}
			a = append(a, n.Attributes[i], n.Attributes[i+1])
		}
		n.Attributes = a
	}
}

func inlineStyleInvalidated(ids []cdp.NodeID) nodeOp {
	return func(n *cdp.Node) {
	}
}

func characterDataModified(characterData string) nodeOp {
	return func(n *cdp.Node) {
		n.Lock()
		defer n.Unlock()

		n.Value = characterData
	}
}

func childNodeCountUpdated(count int64) nodeOp {
	return func(n *cdp.Node) {
		n.Lock()
		defer n.Unlock()

		n.ChildNodeCount = count
	}
}

func childNodeInserted(m map[cdp.NodeID]*cdp.Node, prevID cdp.NodeID, c *cdp.Node) nodeOp {
	return func(n *cdp.Node) {
		n.Lock()
		n.Children = insertNode(n.Children, prevID, c)
		n.Unlock()

		walk(m, n)
	}
}

func childNodeRemoved(m map[cdp.NodeID]*cdp.Node, id cdp.NodeID) nodeOp {
	return func(n *cdp.Node) {
		n.Lock()
		defer n.Unlock()

		n.Children = removeNode(n.Children, id)
		delete(m, id)
	}
}

func shadowRootPushed(m map[cdp.NodeID]*cdp.Node, c *cdp.Node) nodeOp {
	return func(n *cdp.Node) {
		n.Lock()
		n.ShadowRoots = append(n.ShadowRoots, c)
		n.Unlock()

		walk(m, n)
	}
}

func shadowRootPopped(m map[cdp.NodeID]*cdp.Node, id cdp.NodeID) nodeOp {
	return func(n *cdp.Node) {
		n.Lock()
		defer n.Unlock()

		n.ShadowRoots = removeNode(n.ShadowRoots, id)
		delete(m, id)
	}
}

func pseudoElementAdded(m map[cdp.NodeID]*cdp.Node, c *cdp.Node) nodeOp {
	return func(n *cdp.Node) {
		n.Lock()
		n.PseudoElements = append(n.PseudoElements, c)
		n.Unlock()

		walk(m, n)
	}
}

func pseudoElementRemoved(m map[cdp.NodeID]*cdp.Node, id cdp.NodeID) nodeOp {
	return func(n *cdp.Node) {
		n.Lock()
		defer n.Unlock()

		n.PseudoElements = removeNode(n.PseudoElements, id)
		delete(m, id)
	}
}

func distributedNodesUpdated(nodes []*cdp.BackendNode) nodeOp {
	return func(n *cdp.Node) {
		n.Lock()
		defer n.Unlock()

		n.DistributedNodes = nodes
	}
}

func nodeHighlightRequested(n *cdp.Node) {
	// TODO
}

func insertNode(n []*cdp.Node, prevID cdp.NodeID, c *cdp.Node) []*cdp.Node {
	var i int
	var found bool
	for ; i < len(n); i++ {
		if n[i].NodeID == prevID {
			found = true
			break
		}
	}

	if !found {
		return append(n, c)
	}

	i++
	n = append(n, nil)
	copy(n[i+1:], n[i:])
	n[i] = c

	return n
}

func removeNode(n []*cdp.Node, id cdp.NodeID) []*cdp.Node {
	if len(n) == 0 {
		return n
	}

	var found bool
	var i int
	for ; i < len(n); i++ {
		if n[i].NodeID == id {
			found = true
			break
		}
	}

	if !found {
		return n
	}

	return append(n[:i], n[i+1:]...)
}

// isCouldNotComputeBoxModelError unwraps err as a MessageError and determines
// if it is a compute box model error.
func isCouldNotComputeBoxModelError(err error) bool {
	e, ok := err.(*cdp.MessageError)
	return ok && e.Code == -32000 && e.Message == "Could not compute box model."
}